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Introduction

Kay, Sharon.  Correspondence: medical@netiag.com

The International Assistance Group (IAG) Fit-to-Fly Guidelines (F2F) 2025 have been written by medical professionals within the IAG who have volunteered their time and knowledge. 

These guidelines pertain to commercial air travel only. The patient is fit to travel unescorted once they meet all criteria. Should they fall short, a medical escort is recommended.

It is not intended as a training course in aviation medicine or repatriation.  This document does not cover the physical laws of altitude and flight.  

Although highly specialized in patients’ in-hospital care, many physicians are not well versed in the pathophysiological impact of air travel.  IAG recommends engaging with specialists when there is a large discrepancy in F2F recommendations, which may place the patients’ well-being at risk or prejudice the funder. 

Patients must be Individualised; multiple diagnoses, comorbidities and physical reserve need to be considered when deciding fitness-to-fly.  Medical professionals are urged to refer to multiple sections of this document when dealing with complicated cases.

IAG F2F Guidelines 2025 are intended to assist medical professionals make evidence-based decisions when coordinating commercial flight/s for patients who have been acutely ill / injured.  The patient’s clinical state combined with these guidelines determines a delayed date of departure, seating position, need for in-flight oxygen and medical or non-medical escorts.    

The guidelines are based on evidence extracted from internationally published guidelines, as well as journal articles dealing with aeromedical concepts, medical conditions and how these impact each other. 

Ultimately the responsibility to deem a patient F2F is up to the treating doctor.

How to use these guidelines:

Each section has the following subsections:

1. Physiological Considerations Relevant to the System

  • Consider these physiological factors in conjunction with the primary diagnosis

2. Universal Guidelines for Patients flying after an Acute Event of that System

  • These guidelines apply to all conditions of that system
  • Take these into account in conjunction with diagnoses of that system

3. Recommendations for Specific Acute Diagnoses

It is important to refer to all system recommendations when a patient has been diagnosed with multiple pathologies. It is prudent to take the recommendation with the longest interval from date of diagnosis to F2F.

Definitions

Term Definition 
  50m Walk Test (1) A patient can walk 50m at normal pace without developing subjective / objective cardiopulmonary distress.  Simple and valid test showing sufficient cardiopulmonary reserve for inflight conditions. 
Assists when considering inflight supplemental O2. 
May be performed as an inpatient / outpatient. 
Barometric pressure Also known as air pressure or atmospheric pressure.   
Hospital-Associated Deconditioning (2) Patient’s physical, mental, and psychological functioning may be reduced because of acute hospitalization.  Risk factors are the geriatric age group, life-threatening diagnoses, course of admission, social situation, and patients with pre-existing cognitive decline. 
Haemodynamically stable Vital signs are with normal limits, not subject to unexpected changes.  
Hypobaric hypoxia Environmental condition of low O2 concentration at high altitudes. 
Medical Escort Medical professional providing care during patient travel; typically providing a bed-to-bed service 
Non-medical Escort Lay person assisting patients with activities of daily living.  Typically, the patient has completed all treatment and has been discharged from hospital.  May be a family member / friend.  
Long haul flight Continuous flight longer than 4 hours. 
Stable patient (3) The patient’s medical condition is not expected to develop sudden deterioration and does not require frequent or intensive medical treatment. 
  1. Tzani, P. Pisi, G. Aiello, M et al Flying with Respiratory Disease. Respiration 2010;80:161-170 Available from: DOI: 10.1159/000313425
  2. Chen, Y. Almirall-Sanchez, A. Mockler, D. et al. Hospital-associated deconditioning: Not only physical, but also cognitive. Int J Geriatr Psychiatry. 2022;1-13 Available from:doi:10.1002/gps.5687
  3. Vincent, J. Cecconi. M. Saugel, B. Is this patient really “(un)stable”? How to describe cardiovascular dynamic in critically ill patients. Critical Care (2019) 23:272 Available from: http://doi.org/10.1186/s13054-019-2551-1
General Recommendations

These guidelines are not intended to cover flight physiology.  Rather, they apply flight physiology to the pathophysiological process of diseases and the patient’s course of management.

Individualise patient’s prophylactic anticoagulation and graded compression stockings for DVT prevention in high-risk patients. 

At cruising altitude, the cabin is a hypobaric hypoxic environment.  

Inflight, passengers will be breathing the equivalent of FiO2 0.15 at sea level. 

Hospital-Associated-Decompensation (HAD) may occur at any age.  Patient diagnosis, length of stay and course of admission all contribute to HAD.  Physical, psychological, and cognitive functioning may decline. Recovery to baseline functioning may take months. Consider lie-flat seating, and non-medical escort. (2) 

Patients requiring supplemental O2 at altitude require approximately 1-2 L/min additional continuous flow to maintain ground respiratory status. 

Airline Medical Clearance

Kay, Sharon L Correspondence: medical@netiag.com 

Medical clearance from the intended airline will need to be obtained from that medical department.   

Application will need to be submitted in writing on the respective MEDIF form at least 72 hours before departure.  The airline’s medical department may request additional medical information other than stated on the MEDIF. 

Application for stretcher transport may take a couple weeks’ lead time.  

Compulsory Applications 

  • Stretcher transport 
  • Medical escort 
  • Medical equipment: incubator, upper airway suction, nebuliser, medications 
  • Airport / inflight / layover oxygen 
  • Airport clinic admission during layovers 
  • Medical condition / recovery from such which may be adversely affected by the flight environment 
  • Special seating arrangement: bulkhead, additional leg room, infant cot.  Patients may not be seated at emergency exits. 
  • Patient’s condition may be a hazard / cause discomfort to other passengers  
  • Patient who is incapable of performing activities of day living 
  • Non-medical escort 

General criteria for patient acceptance

  • Good prognosis for the trip
  • Patient is able to remain seated upright for at least 45 minutes unaided
  • Clinical condition will not be offensive to other passengers – for example odour
  • Patient is not a danger to themselves nor the aircraft / other passengers
  • Toileting is managed appropriately and discretely, no bed pans / urinary bottles are permitted
  • Medical equipment must be battery operated with 150% battery capacity

The airline and the pilot of the aircraft hold the ultimate decision for accepting or rejecting the application.

Inflight Physiological Considerations Relevant to all Systems
Kay, Sharon L Correspondence: medical@netiag.com 

These guidelines are not intended to cover flight physiology.  Rather, they apply flight physiology to the pathophysiological process of diseases and the patient’s course of management.  

  • At cruising altitude, the cabin is a hypobaric hypoxic environment.   
  • Inflight, passengers will be breathing the equivalent of FiO2 0.15 at sea level.  
  • Hospital-Associated-Decompensation (HAD) may occur at any age.  Patient diagnosis, length of stay and course of admission all contribute to HAD.  Physical, psychological, and cognitive functioning may decline. Recovery to baseline functioning may take months. Consider lie-flat seating, and non-medical escort. (2)  
  • Patients requiring supplemental O2 at altitude require approximately 1-2 L/min additional continuous flow to maintain ground respiratory status.  
  • Individualise patient’s prophylactic anticoagulation and graded compression stockings for DVT prevention in high-risk patients.  
Commercial Medical Escort
Kay, Sharon L Correspondence: medical@netiag.com 

Medical Escort Capabilities

IAG recommends selecting a Service Provider with international accreditation.   

  1. European Aero-Medical Institute (EURAMI)  
  2. Commission on Accreditation of Medical Transport Systems (CAMTS)
  3. National Accreditation Alliance of Medical Transport Applications (NAAMTA Global) 

Levels of Care  

A commercial medical escort transport mission is defined as the transport of a patient whose condition warrants monitoring and minimal medical attention on a commercial aircraft.  Transfer may include multiple flights including airport layovers.   

Patients’ level of care should be individualised according to their clinical status, medical needs and HAD.  

The medical attendant must be certified to practice independently with ability to attend to the patient should they complicate.  All administration of medication and procedures should be well within their scope of practice.  

Commercial Airline Medical Escort Standard Care 

A stable patient requiring basic medical care for the duration of the transfer.  One medical attendant is appropriate. 

Commercial Airline Medical Escort Advanced Care  

  • Stable patients who require nursing care on the transfer such as (but not limited to): 
    • O2 supplementation 
    • Drainage bags – urinary catheter, surgical drains, NG tube bags 
    • Dressing changes of open wounds 
    • Medication administration / supervision of self-administration 
    • Dietary supervision 
    • Potential cardiac deterioration requiring emergency medical care 
    • Potential diabetic complications requiring emergency medical care 
    • Potential respiratory complications requiring emergency medical care. 
  • At least one medical attendant is permitted. 

Commercial Airline Medical Escort Paediatrics 

  • Transfer of neonates by commercial medical escort is not recommended. 
  • Stable paediatric patients requiring nursing care such as (but not limited to): 
    • O2 supplementation 
    • Drainage bags – urinary catheter, surgical drains, NG tube bags 
    • Dressing changes of open wounds 
    • Medication administration 
    • Potential cardiac deterioration requiring emergency medical care 
    • Potential respiratory complications requiring emergency medical care 
  • Medical personnel with additional qualifications in paediatric intensive care are recommended. 

Commercial Medical Escort Stretcher Transport 

  • Stable patients with limited mobility. 
  • Patients who are unable to obtain or maintain an upright position for longer than 45 minutes. 
  • Patient examples are (but not limited to): 
    • Paralysis 
    • Neurological deficit post stroke 
    • Back injuries / recent surgery 
  • A urinary catheter is recommended. 
  • Bowel prep is recommended no closer than 24 hours prior to departure. 
  • Two medical escorts are recommended. 

Advanced Life Support (ALS) or Registered Nurse with ICU diploma 

  • Scope of practice for a Registered Nurse, Critical Care Attendant (Paramedic) or Respiratory Therapist  
    • Stable patient  
    • Medical care including (but not limited to): 
      • Basic airway management  
      • Supplemental oxygen   
      • Blood glucose control  
      • Fluid drainage bags  
      • Dressing changes   
      • Administration of oral / intermuscular medication  
      • Dietary supervision  

Medical Doctors as Escorts 

  • Medical doctor escorts are not required in most cases – think about in the case of ALS 
  • Consider an AA should the patient require complex care. 

References 

  1. CAMTS Medical Escort Accreditation Standards 7th Edition (2023) Commission on Accreditation of Medica Transport Systems.  Available from https://www.camts.org/standards/ 
The Cardiovascular System
Sharon Kay, Gabriella Hosea, Julien Marrel, Annelieke Hulzebosch, Michelle Nathan Correspondence: medical@netiag.com 
  • Consult other organ systems for patients with multiple comorbidities. 
  • Consider the longest delay for a safe departure for patients following a complicated course of illness. 
Physiological Considerations Relevant to the Cardiovascular System  
  • At cruising altitude, the cabin is a hypobaric hypoxic environment.  
  • Passengers will be breathing the equivalent of FiO2 0,15 at sea level.  
  • Heart rate, respiratory rate and blood pressure will increase as a compensatory measure to hypobaric hypoxia. (3)  
  • Increased heart rate with greater myocardial contraction results in an increased cardiac output, leading to higher O2 demand.  O2 demand may outstrip oxygen supply. (3)  
  • A Hb < 4,34 mmol/L (7 g/dL), cardiac output may increase in response to lower O2 carrying capacity.  A Hb 4,34 – 10 mmol/L (7 – 10g/dL) should be targeted and individualised according to patient pathology and cardiopulmonary reserve. (4,5,17)  
  • Blood pressure may increase with acceleration and deceleration forces on take-off and landing respectively. (3)  
  • Noise and vibration may increase systolic and diastolic blood pressure. (3)  
  • Hypobaric hypoxia may increase the frequency of PVC’s.  Prolonged mild to moderate hypoxia may cause sustained PVCs with possible degradation into clinically significant ventricular arrythmias. (6)  
  • The volume of intrathoracic free air post thoracic surgery increases at altitude.  Respiratory and cardiac function may be adversely affected by the greater volume. (1)  
  • The 50m Walk Test is a simple and validated test to demonstrate cardiopulmonary reserve (1).  Should the patient not be able to complete the entire 50m without stopping, then they are not FTF independently.     
  • Patients’ cardiopulmonary reserve may be adversely affected by HAD.  
  • Rupture of arterial aneurysms at altitude has not been proven in the clinical setting.  In-flight aortic aneurysm rupture has not been reported in the literature. (8)  
  • Hypobaric hypoxia may influence tissue oxygenation in peripheral vascular diseases.  

Assessment of Cardiopulmonary Reserve
  • The Hypoxic Challenge Test is the gold standard to predicting hypoxaemia inflight, but this test is not widely available. (1)  The patient is exposed to FiO2 0.15 for 20 minutes.  At this point, an ABG is taken.  If the Pa O2 > 50mmHg and SpO2 > 85%, then the patient may not require supplemental O2 at altitude.   
  • The 50m Walk-Test is a reliable and easy test to run.  The patient walks 50 m at a brisk pace, if the patient can complete the 50 m without stopping and has not desaturated SpO2 < 85%, then they may not require supplemental O2 at altitude.  then demonstrates sufficient cardiopulmonary reserve. (1, 2, 6).  Alternatively, the patient can climb 12 stairs. 
  • The 6-Minute-Walk-Test is more accurate than the 50m Walk-Test to predict in-flight O2 desaturations. (1,2) The patient may start the walk is SpO2 > 95% at rest.  They attempt to walk for 6 minutes at their own pace, if the SpO2 remains >84%, the patient may not require supplemental O2 at altitude. (1, 2) 
  • Resting SpO2 at sea level does not reliably predict respiratory decompensation in the cabin environment in patients with respiratory disease/s. (1,3,6) 
  • FEV1 does not reliably predict respiratory decompensation in the cabin environment in patients with respiratory disease/s. (1,6) 
  • Predictive equations estimating the degree of desaturation in-flight are not reliable. (1,3) 
         Universal Guidelines for Patients Flying after an Acute Cardiovascular Insult 
RecommendationPatient / Member
WCHS – All patients   
Anaemia– Assess patient’s baseline Hb
– Assess Hb within patient’s context of acute / chronic disease
– Hb > 5,3 mmol/L (> 8,5 g/dL) is acceptable for patients with no cardiac comorbidities (5, 7)
– Patients suffering from cardiorespiratory comorbidities, Hb > 6,0 mmol/L (> 9 g/dL) is acceptable (5, 7)  
Supplemental O2 – Poor cardiopulmonary reserve
– Significant pulmonary comorbidities 
– Anaemia 
– Post significant cardiac insult
– Venous thromboembolism 
– Peripheral vascular disease 
– Congenital cardiac disease   
Graded compression stockings   – All patients 
Seating with additional leg room – Supplemental O2 
– Medical escort rendering medical assistance
– Accidental injury may occur if patient seated in a confined space   
Lie-flat seating – Poor cardiopulmonary reserve
– Acute vascular conditions 
– Supplemental O2 
– Prolonged upright seating may be detrimental to recovery / acute clinical state 
– Immediate post-operative phase of recovery 
– Medical escort rendering medical assistance
– HAD   
Medical Escort – Supplemental O2  
– Recovery after acute CCF 
– Return before recommended FTF date   
Non-medical Escort – HAD 
– Discharge instruction to limit specific physical movement – e.g. pacemaker/ICD patients may not lift the ipsilateral arm above the shoulder
– Unable to complete activities of daily living  
Recommendations for Specific Acute Cardiovascular Conditions  
 
Acute Coronary Syndrome  
Condition  Assessment  Recommendation  
STEMI  or  NSTEMI  or  Unstable Angina  or  Angioplasty Low Risk (4, 1)  
All of the following criteria must be met to qualify as low risk 
– Treatment complete / discharged AND  
– Successful reperfusion AND  
– No complications AND  
– LVEF > 45% AND  
– Age < 65 years AND  
– First event    		– 3 days after completing treatment  
– Refer to universal cardiac considerations      
 Medium Risk (4, 1)  
Medium risk are patients not classified as low or high risk  
– Treatment complete / discharged  
– Successful reperfusion  
– No complications  
– LVEF > 40%  
– No signs / symptoms of provocable ischemia   		Medium Risk 
– 10 days after completing treatment  
– Assess cardiopulmonary reserve 
– Supplemental O2 if required 
– Refer to universal cardiac considerations  
– If considering traveling 3 – 9 days after completing treatment, a medical escort is recommended   
Definition of High-Risk Patients 
Only one of the following is required 
– Cardiogenic shock  
– LVEF < 40%  
– Ventricular arrythmias  
– Acute CCF  
– CABG / ICD / pacemaker indicated  
Assessment of high-risk  
– Treatment complete / discharged  
– Successful reperfusion  
– Any complications managed and stabilised    
– Rhythm controlled  
– No signs / symptoms of acute CCF  
– No signs / symptoms of provocable ischemia  		High Risk  
– 14 days after completing treatment  
– Medical escort with scope of practise to managed acute cardiac emergencies 
– Assess cardiopulmonary reserve 
– Supplemental O2  
– Individualise lie-flat seating according to cardiopulmonary reserve 
– Refer to universal cardiac considerations    
Coronary Artery Bypass Graft (CABG) Uncomplicated / Elective CABG (4, 12)  
– Assess Hb and refer to Anaemia – – – Recommendations  
– No residual intrathoracic air on CXR  
– No signs / symptoms of acute CCF  
– Rate and rhythm controlled    
Complicated CABG defined as, (but not limited to):  
– Surgical complications  
– Anaesthetic complications  
– Post-operative complications    		– 10 days after treatment completed  
– Medical escort with scope to manage acute cardiac emergencies 
– Assess cardiopulmonary reserve 
– Supplemental O2  
– Lie-flat seating   
– Refer to universal cardiac considerations      
– Individualise FTF according to type and severity of complication/s  
– Refer to universal cardiac considerations  
Cardiac Arrythmia  
Condition  Assessment  Recommendation  
Supraventricular tachycardia (SVT) (14)    – No signs or symptoms of acute coronary syndrome  
– Haemodynamically stable  
– No signs / symptoms of acute cardiac failure  
– Rate controlled  
– Appropriately anticoagulated    		– Individualise according precipitant of SVT and co-morbidities  
– Refer to universal cardiac considerations    
Ventricular Arrythmias  VT or VF (14)  – Uncomplicated cardioversion  
– No ICD indicated   
– Underlying structural disease investigated and managed if indicated  
– Reversible causes treated  
– Haemodynamically stable    		– 2 days after normal rhythm restored (6)  
– Refer to universal cardiac considerations   
– If ICD inserted, refer to relevant section   
Symptomatic Bradycardia  – Appropriate workup completed  
– Reversible causes treated   
– Asymptomatic   
– No further episodes for 24 hours   		– 2 days after acceptable rate obtained  
– Refer to universal cardiac considerations  
– If pacemaker inserted, refer to relevant section     
Pacemaker Inserted  – Permanent pacemaker inserted   
– Uncomplicated procedure  
– Pacemaker fully functional  
– Rate controlled  
– No iatrogenic pneumothorax    
– Temporary pacemaker inserted  		– 2 days after insertion (15,4,7,16)  
– Non-medical escort  
– Refer to universal cardiac considerations  
– Travel with device ID card on their person   
– Consider AA     
ICD Inserted  – Uncomplicated cardioversion  
– Uncomplicated procedure  
– ICD confirmed as fully functional  		– 3 days after insertion (15,4,7,16)  
– Non-medical escort – patient will have limited upper limb movement 
– Refer to universal cardiac considerations  
– Travel with device ID card on their person   
Cardiac Valve Conditions  
Condition  Assessment  Recommendation  
Open Cardiac Valve Replacement or Repair  – Treatment completed  
– Uncomplicated surgery (8)  
– No signs / symptoms of acute CCF (8)  
– LVEF > 45% (25)   
– All intra-thoracic drains removed  
– No intrathoracic free air on CXR    		– 10 days post-surgery (18,19,20)  
– Assess cardiopulmonary reserve 
– Supplemental O2  
– Assess Hb and refer to Anaemia Recommendations 
– Medical escort if travelling < 10 days post-surgery with scope of managing acute cardiac emergencies 
– Lie-flat seating 
– Refer to universal cardiac considerations   
Transcatheter Aortic Valve Implantation (TAVI)  – Treatment complete  
– Uncomplicated procedure  
– No signs or symptoms of CCF (8)  
– LVEF > 45% (8)  
– No complications at arterial access point  
– No pulmonary hypertension   		– 7 days post-surgery (10, 11, 12)  
– Assess cardiopulmonary reserve 
– Supplemental O2  
– Assess Hb and refer to Anaemia – Recommendations 
– Medical escort if travelling < 7 days post-surgery  
– Refer to universal cardiac considerations   
Cardiac Function  
Condition  Assessment  Recommendation  
Acute CCF   or   Acute-on-chronic cardiac failure      – Underlying aetiology identified (10)  
– Aetiology managed appropriately and stabilised (10)  
– Complications managed appropriately and stabilised (21)  
– Cardiac markers showing downward trend   		– Individualise FTF according to type and severity  
– Assess cardiopulmonary reserve 
– Supplemental O2  
– Assess Hb and refer to Anaemia Recommendations  
– Medical escort with scope to manage acute decompensated CCF 
– Refer to universal cardiac considerations    
Acute Pulmonary Oedema  – Cardiogenic pulmonary oedema  – Refer to guidelines according to underlying pathology    
– Non-cardiogenic pulmonary oedema  – Refer to guidelines according to underlying pathology    
Hypertensive Emergencies  
Condition  Assessment  Recommendation  
Hypertensive Urgency (25,26)  – No headache, dizziness, chest pain, dyspnea, vomiting, visual changes, or other symptoms  
– No evidence of worsening / new end-organ dysfunction   
– Reversible causes identified and addressed (non-compliance / changes of time zones)  
– Medication/s finalised  
– BP stable     		– 2 days after BP stable   
– Refer to universal cardiac considerations  
Hypertensive  Emergency (25,26)  – End-organ insult diagnosed and treated appropriately  – Individualise FTF according to the severity and type of end-organ insult   
– Refer to universal cardiac considerations    
     Congenital Cardiac Conditions 
– Distinguish risk factors between cyanotic and acyanotic congenital cardiac conditions 
– For patients requiring an upgrade of care, consider AA transfer 
– Consult the referring / receiving cardiologist for expert opinion if needed   
Cyanotic Congenital Cardiac Conditions (22,23,24,27) – Universal congenital cardiac condition recommendations: 
– O2 supplementation for cyanotic congenital cardiac conditions  
– O2 supplementation for all long-haul flights 
– Refer to universal cardiac considerations   
– Pulmonary Atresia, Tricuspid Atresia, Tetralogy of Fallot, Critical Pulmonary Stenosis 
– Cyanotic conditions 
– Decreased pulmonary flow 
– PDA dependent for pulmonary blood flow 
– Right to left shunting through PFO / VSD 		Individualise keeping in mind the following:  
– Hypobaric hypoxia causes pulmonary vasoconstriction with higher pulmonary vascular pressure  
– High pulmonary vascular pressure decreases pulmonary blood flow  
– Right atrial pressure increases which inhibits closure of PFO    
– Hypoplastic Left Heart Syndrome, Coarctation of the Aorta, Critical Aortic Stenosis 
– Left to right intracardiac shunting 
– Excess flow of blood into pulmonary vasculature 
– Decreased systemic blood flow    		Individualise keeping in mind the following:  
– Hypobaric hypoxia causes pulmonary vasoconstriction with higher pulmonary vascular pressure 
– High pulmonary vascular pressure decreases pulmonary blood flow 
– Transposition of the Great Arteries, Truncus Arteriosus 
– Mixed pulmonary and systemic blood flow   		– Individualise according to severity of condition and clinical status  
Vascular Conditions  
Condition  Assessment  Recommendation  
Aortic aneurysm (28,29)  Physiological considerations at altitude: 
– HR and BP increase    

Theoretical risk of rupture  
– Hypertension increases the risk for aneurysm rupture  
– Rate of increase in size of the aneurysm is directly related to the risk of rupture; be it on the ground or in-flight     

Theoretical risk of rupture at altitude: 
Literature does not have compelling evidence demonstrating an increased risk of rupture for a stable aortic aneurysm at altitude    		– Individualise FTF according to aneurysm type   
– Individualise FTF according to cardiovascular co-morbidities  
– Refer to universal cardiac considerations        
DVT (1,30)  Uncomplicated DVT  
– Mobilising without pain  
– No signs / symptoms of PE  
– Local symptoms / signs improving       




   
Large burden / Proximal DVT   
Defined as thrombus proximal to popliteal vein    

Inpatient management with 
– Oral anticoagulation or   
– IV UFH or  
– Thrombolytics, endovascular intervention with or without placement of IVC filter    

Assessment  
– Mobilising   
– Haemodynamically stable  
– No signs / symptoms of PE  
– No complication at puncture site (if applicable)    		 - Appropriately anticoagulated (5)  
– LMWH 24 hours after first dose  
– NOAC 24 hours after first dose  
– Warfarin when INR 2 – 3 may take up to 2 weeks  
– Lie-flat seating with limb elevation  
– Facilitate education for LMWH self-administration (if required)  
– Refer to universal cardiac considerations      

– Individualise based on patient management   
– Oral anticoagulation  
– 5 days after first dose of anticoagulant (excepting warfarin)  
– Thrombolytics or endovascular intervention  
– 5 days after starting appropriate oral anticoagulants (may not be the same say as the intervention was performed)  

– Lie-flat seating with limb elevation  
– Facilitate education for LMWH self-administration (if needed)  
– Refer to universal cardiac considerations    
Acute Pulmonary Embolism (PE)  
(31,32,33)  		Haemodynamically stable PE – small burden  
– No pulmonary hypertension AND  
– No RV strain AND  
– No respiratory failure AND  
– No supplemental oxygen  
– Appropriate anticoagulation (except warfarin)  
   
Haemodynamically stable PE – with right heart strain defined as 
– Haemodynamically stable with  
– RV strain OR 
– Myocardial ischemia OR  
– RV dilatation OR  
– RV dysfunction   
Assessment  
– Appropriate anticoagulation  
– No signs of clinical deterioration since first dose of anticoagulation   
– No signs / symptoms of RV strain   
– Cardiopulmonary comorbidities controlled  
– Vital signs consistent   
– Cardiac enzymes stable / decreasing trend  
  
Haemodynamically unstable PE (massive PE) defined as  
– Hypotensive 
– Shocked state requiring vasopressor support  
– Persistent bradycardia  
– Cardiac arrest with ROSC  
 
Transcatheter intervention  
– Appropriately anticoagulated  
– Cardiopulmonary comorbidities controlled  
 
Surgical embolectomy  
– No residual intrathoracic air   
– Asymptomatic  
– Cardiopulmonary comorbidities controlled		Haemodynamically stable PE – small burden  
– LMWH 48 hours after first dose  
– NOAC 48 hours after first dose  
– Warfarin when INR 2 – 3 may take up to 2 weeks  
– Refer to universal cardiac considerations  
  
Haemodynamically stable – with right heart strain  
– 5 days after first dose of anti-coagulant  
– Assess Hb and refer to Anaemia Recommendations  
– Assess cardiopulmonary reserve 
Supplemental O2  
– Medical escort with scope of practise to administer O2 
– Refer to universal cardiac considerations  
  
Transcatheter intervention  
– 10 days after intervention  
– Assess Hb and refer to Anaemia Recommendations  
– Assess cardiopulmonary reserve 
– Supplemental O2  
– Medical escort with scope of practise to administer O2 
– Lie-flat seating  
– Refer to universal cardiac considerations  
 
Surgical embolectomy  
– 14 days post procedure  
– Assess Hb and refer to Anaemia Recommendations  
– Assess cardiopulmonary reserve 
– Supplemental O2  
– Medical escort with scope of practise to administer O2 
Lie-flat seating  
– Refer to universal cardiac considerations  
Arterial thrombus  – Individualised based on location, management and sequalae.    
– Refer to relevant organ system  
– Refer to universal cardiac considerations
Peripheral vascular disease  – Open wounds suitably dressed  
– No foul odour  
– Any acute infection resolved / resolving  
– No threatened limb  
– Cardiac conditions controlled  		– Open wounds suitably dressed  
– No foul odour  
– Any acute infection resolved / resolving  

References

1. 
Ahmendzai, S. Balfour-Lynn, M. Bewick, T. Buchdahl, R. Coker, RK. (2011). Managing Passengers with Stable Respiratory Disease Planning Air Travel: British Thoracic Society recommendations. Thorax An International Journal of Respiratory Medicine. Journal of the British Thoracic Society. Volume 66 Supplement September 2011. ISSN 0040-6376 (print) ISSN 1468-3296 (online)  
 
2. 
Chen Y, Almirall-Sánchez A, Mockler D, Adrion E, Domínguez-Vivero C, Romero-Ortuño R. (2022) Hospital-associated Deconditioning: Not only physical, but also cognitive. Int J Geriatr Psychiatry. 2022 Mar;37(3):10.1002/gps.5687. doi: 10.1002/gps.5687. PMID: 35142397; PMCID: PMC9303382.  
 
3. 
Okyay, K. (2021). Systemic Arterial Hypertension and Flight. Anatol J Cardiol. 2021; 25(Suppl 1): S7-S9. Published 2021 Aug 1. Available from doi: 10.5152/Anatol JCardiol.2021.S104  
 
4. 
Smith, D. Toff, W. Joy, M. Dowdall, N. Johnston, R. et al. (2010) Fitness to Fly for Passengers with Cardiovascular Disease. The report of a working group of the British Cardiovascular Society. Heart. 2010 Aug; 96 Suppl 2:ii1-16. Available from https://heart.bmj.com/content/96/Suppl_2/ii1 . Last visited 11 April 2025 
 
5. 
Chang, D. (2013). What are the Indications for a Blood Transfusion? The Hospitalist. Society of hospital Medicine. September 1, 2013. Available from https://www.the-hospitalist.org/hospitalist/article/125662/what-are-indications-blood-transfusion Last visited 11 April 2025 
 
6. 
Meyer, MJ. Mordukhovich, I. Coull, BA. McCracken, J. Wellenius, GA. et al (2023) Impact of Simulated Flight Conditions on Supraventricular and Ventricular Ectopy. Sci Rep 13, 481 Available from: https://doi.org/10.1038/s41598-022-27113-x  
 
7. 
Erkan, AF. (2021) Is Air Travel Safe for Patients with Cardiac Implantable Electronic Devices? The Anatolian Journal of Cardiology. Turkish Society of Cardiology. Anatol J Cardiol. 2021; 25(Suppl 1):S26-S28. Published online 2021 Aug 1. Available from doi: 10.5152/Anatol JCardiol.2021.S110  
 
8. 
UK Civil Aviation Authority. Passenger Health FAQs Am I fit to fly. Frequently asked questions about passenger health. [online] Last visited August 2024. Available from www.caa.co.uk/passengers-and-public/before-you-fly/am-i-fit-to-fly/health-information-for-passengers/passenger-health-faqs-am-i-fit-to-fly/#. Last visited August 2024  
 
9. 
IATA Medical Advisory Group (2020) Medical Manual Edition 12 IATA Available upon request from https://www.iata.org/en/publications/medical-manual/ 
 
10. 
Green, B. Hulzebosch, A. Guikema, P. Nyhof, P. Manten, B. et al (2023) Guidelines Indications and Requirements of Patient Transportation by Air 2023. 7th Edition Available from https://omar.nl/?lang=en  
 
11. 
Alves, P. Dowdall, N. Evans, AD. Hudson, MF. Thibeault, C. et al (2014) Medical Considerations for Airline Travel. Aerospace Medical Association (2014 – 2016) Available from https://www.asma.org/publications/medical-publications-for-airline-travel/medical-considerations-for-airline-travel  
 
12. 
Canadian Cardiovascular Society. (2003) Drive and Fly (2003) 8. Flying: Cardiovascular Conditions. Available on https://ccs.ca/guideline/drive-and-fly-2003/chapter-8-flying-cardiovascular-conditions/ Last visited August 2024  
 
13. 
Shrikrishna, D. Coker, RK. (2011). Managing Passengers with Stable Respiratory Disease Planning Air Travel: Bristish Thoracic Society Recommendations. Thorax 2011 66: 831-833. First published online July 31, 2011. Available from doi: 10,1136/thoraxjnl-2011-200694  
 
14. 
Katkat F. Flight Safety in Patients with Arrhythmia. (2021) Anatol J Cardiol. 2021 Aug;25(Suppl 1):24-25. Available from: doi: 10.5152/AnatolJCardiol.2021.S109.  
 
15. 
IAG (2015) International Assistance group Fitness to Fly Guideline (2015) Available from online membership site  
 
16. 
Przilille, O. Weise, FK. Nowak, B. 2019 Mit Herzschrittmacher oder Defibrillator auf reisen [Travelling with a Pacemaker or Implanted Defibrillator]. Herzschrittmacher Elektrophysiol. 2019 Jun;30(2):144-149. German. doi: 10.1007/s00399-019-0624-0. PMID:31025098  
 
17. 
Tanimura,M. Dohi,K. Fujimoto, N. Moriwaki, K. Omori, T. et al. (2017) Effect of Anemia on Cardiovascular Hemodynamics, Therapeutic Strategy and Clinical Outcomes in Patients with Heart Failure and Hemodynamic Congestion. Circulation Journal Volume 81 Issue 11  doi: 10.1253/circj.CJ-17-0171. Epub 2017 Jun 17 
 
18. 
NHS Barts Health NHS Trust. (2024). Transcatheter Aortic Valve Implantation (TAVI) Service. Going home after your TAVI. [online] Available from https://www.bartshealth.nhs.uk/tavi/ Last visited August 2024.  
 
19. 
Transcatheter Aortic Valve Implantation (TAVI). Ed 2 (v1) The Leeds Teaching Hospitals NHS Trust. Medical Illustration Services. 2023 
 
20. 
Medical Tourism International (2024) Transcatheter Aortic Valve Replacement Information and International Destinations. [online] Available from https://www.medicaltourismdoctors.com/specialties/cardiology/transcatheter-aortic-valve-replacement Last visited August 2024  
 
21. 
Njoroge, JN. Teerlink, JR. (2021) Pathophysiology and Therapeutic Approaches to Acute Decompensated Heart Failure. American Heart Association. Circulation Research volume 128, Issue 10, 14 May 2021; Pages 1468 – 1486 Available from https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.121.318186#sec-12  
 
22. 
Hasan, A. 2016 Relationship between High Altitude and Congenital Heart Disease. Cardiovascular Society of India. Published by Elsevier B. V. 19 January 2016. Available from http://dx.doi.org/10.1016/j.ihj.2015.12.015  
 
23. 
Laird, R, Jnr. 2014 Effects of Altitude on Children with Congenital Heart Disease. Pediatric Heart Specialists. Available from https://pediatricheartspecialists.com/heart-education/blog/64-effects-of-altitude-on-children-with-congenital-heart-disease Last visited August 2024  
 
24. 
Tacoy, G. 2021 Congenital Heart Disease and Air Travel. Anatol J Cardiol. 2021; 25(Suppl 1): S18-19 Published online 2021 Aug 1. Available from doi: 10,5152/AnatolJCardiol.2021.S107  
 
25. 
Okyay, K. 2021. Systemic Arterial Hypertension and Flight. Anatol J Cardiol. 2021; 25(Suppl 1): S7-S9. Published 2021 Aug 1. Available from doi: 10.5152/AnatolJCardiol.2021.S104  
 
26. 
Breu, AC. Axon, RN. Acute Treatment of Hypertensive Urgency. Journal of Hospital Medicine Vol 13, No 12, December 2018. Society of Hospital Medicine. Available from doi: 10.12788/jhm.3086  
 
27. 
Ossa Galvis, MM. Bhakta, RT. Tarmahomed, A. et al. Cyanotic Heart Disease. [Updated 2023 Jun 26] In: StatPearls [Internet]. treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from https://www.ncbi.nlm.nih.gov/book/NBK500001/  Last visited 11 April 2025 
 
28. 
Mutlu, O. Salman, HE. Al-Thani, H. El-Menyar, A et al. 2023 How does Hemodynamics Effect Rupture Tissue Mechanics in Abdominal Aortic Aneurysm: Focus on Wall Shear Stress Derived Parameters, Time-average Wall Shear Stress, Oscillatory Shear Index, Endothelial Cell Activation Potential, and Relative Residence Time. Computers in Biology and Medicine. Volume 154, March 2023, 106609 Available from: https://doi.org/10.1016/j.compbiomed.2023.106609  
 
29. 
Penning de Vries, BBL. Kolbert, JL. Meerwaldt, R. Groenwold, RHH. 2017. Atmospheric Pressure and Abdominal Aortic Aneurysm Rupture: results from a time series analysis and case-crossover study. Vasc Endovascular Surg. 2017 Oct; 51(7): 441-446. Published online 2017 Jul 25. Available from doi: 10.1177/1538574417713909  
 
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Moll, S. Acute DVT/PE and Airline Travel. [Updated March 21, 2020]. Clot Connect. University of North Carolina Blood Research. Available from: https://clotconnect.org/2020/03/21/acute-dvt-pe-and-airline-travel/ Last visited August 2024  
 
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Russel, C. Keshavamurthy, S. Saha, S. Classification and Stratification of Pulmonary Embolism. Int J Angiol. 2022 Sep 2;31(3):12 – 165. Available from doi: 10,1055/s-0042-1756218  
 
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Respiratory System
Kay, S. Hosea, G.  Marrel, J. Hulzebosch, A.  Contributions from The Medical Stream Delegates at IAG Global Forum November 2024, Bratislava, Slovakia. Correspondence: medical@netiag.com 
  • Consult other organ systems for patients with multiple comorbidities.  
  • Consider the longest delay for a safe departure for patients following a complicated course of illness. 

Physiological Considerations Relevant to the Respiratory System  

  • Generating a higher Minute Volume (MV) is the physiological response to hypobaric hypoxia. Creating a greater Tidal Volume (TV) contributes more than a higher Respiratory Rate (RR) in this compensation. (4) 
  • Cardiac compensation to hypoxia causes pulmonary vasoconstriction, blood flow is diverted to the apexes. (4) This generates a ventilation-perfusion (V/Q) mismatch.  Masses or diseases located in the apexes, will heighten the mismatch, causing early respiratory compromise. Other diseases affected by V/Q mismatch are Chronic Obstructive Pulmonary Disease (COPD), pulmonary embolism (PE), pulmonary fibrosis, cystic lung disease, pulmonary lobe resection. (4) 
  • Pulmonary vasoconstriction may cause clinically significant increases in pulmonary vascular pressure. (1)   
  • Hospital-Associated-Deconditioning (HAD) will cause respiratory distress due to wasted respiratory musculature. (4) 
  • Patients with neuromuscular disease / chest wall disease will tire quickly with the higher respiratory workload. 
  • An arterial blood gas measurement for chronic lung disease patients of PaO2 < 67 mmHg on the ground, can be expected to drop to PaO2 < 50 mmHg in-flight. (4) 
  • At cruising altitude, free air in the thoracic cavity increases approximately 30%. (4) 
  • Cabin humidity is approximately 10%. Dry air may lead to airway irritation, and regression of symptoms in particular diseases. 
  • Respiratory conditions can negatively impact cardiac functioning, special consideration should be given to patients with cardiopulmonary diseases. (1) 
  • Respiratory decompensation can be accelerated by multiple comorbidities. 

Assessment of Cardiopulmonary Reserve 

  • The Hypoxic Challenge Test is the gold standard to predicting hypoxaemia in-flight, but this test is not widely available. (1)  The patient is exposed to FiO2 0.15 for 20 minutes.  At this point, an ABG is taken.  If the Pa O2 > 50mmHg and SpO2 > 85%, then the patient may not require supplemental O2 at altitude.   
  • The 50m Walk-Test is a reliable and easy test to run.  The patient walks 50 m at a brisk pace, if the patient can complete the 50 m without stopping and has not desaturated SpO2 < 85%, then they may not require supplemental O2 at altitude. (1, 2, 6).  Alternatively, the patient can climb 12 stairs. 
  • The 6-Minute-Walk-Test is more accurate than the 50m Walk-Test to predict in-flight O2 desaturations. (1,2) The patient may start the walk is SpO2 > 95% at rest.  They attempt to walk for 6 minutes at their own pace, if the SpO2 remains >84%, the patient may not require supplemental O2 at altitude. (1, 2) 
  • Resting SpO2 at sea level does not reliably predict respiratory decompensation in the cabin environment in patients with respiratory disease/s. (1,3,6) 
  • FEV1 does not reliably predict respiratory decompensation in the cabin environment in patients with respiratory disease/s. (1,6) 
  • Predictive equations estimating the degree of desaturation in-flight are not reliable. (1,3) 
         Universal Guidelines for Patients flying after a Respiratory Illness 
Recommendation Patient / Member 
WCHS  – All patients   
Graded compression stockings   – All patients  
Anaemia – Assess patient’s baseline Hb 
– Assess Hb within patient’s context of acute / chronic disease  
– Hb > 5,3 mmol/L (> 8,5 g/dL) is acceptable for patients with no cardiac comorbidities (5, 7) 
– Patients suffering from cardiorespiratory comorbidities, Hb > 6,0 mmol/L (> 9 g/dL) is acceptable (5, 7)  
Supplemental O2  – Poor cardiopulmonary reserve 
– Cardiovascular comorbidities 
– Acute exacerbations of chronic lung diseases 
– Acute infection on the background of chronic lung disease  
– Hospital-Associated-Decompensation   
Medical escort – Supplemental O2 
– Upper airway care 
– Recent tracheostomy requiring care 
– Patient flying before recommended fit-to-fly date  
Seating with additional leg room  – Supplemental O2  
– Medical escort  
– Accidental injury may occur if patient seated in a confined space    
Lie-flat seating – Hospital-Associated-Decompensation 
– Supplemental O2  
– Medical escort 
– Poor cardiorespiratory reserve  
– Immediate post-operative phase  
Non-medical escort – Unable to complete activities of daily living  
   Recommendations for Specific Acute Respiratory Conditions  
Condition  Assessment  Recommendation  
Acute bronchitis (4,8) – Cardiac comorbidities at baseline 
– No longer infectious 
– 4 days after completing treatment  
– Cardiopulmonary reserve assessed  		– Individualise supplemental O2  
– Medical escort with scope to titrate O2 and administer nebulisation 
– Refer to universal respiratory guidelines  
Acute exacerbation of non-cystic fibrosis bronchiectasis (6,9) – Cardiopulmonary reserve assessed 
– Assess Hb and refer to Anaemia Recommendations 
– Reached near clinical baseline state 
– Underlying trigger resolved 
– Airway suctioning no longer required 
– Mucous clearance manageable by patient   		– Individualise supplemental O2  
– Individualise medical escort with scope to clear upper airway obstruction and titrate O2 therapy 
– Refer to universal respiratory guidelines  
Acute Exacerbation of Chronic Obstructive Pulmonary Disease / Chronic Obstructive Airway Disease – Underlying cause resolved, see relevant section if applicable  
– O2 requirements returned to near clinical baseline 
– 5 days after returning to near clinical baseline 
– Cardiac comorbidities controlled 
– Cardiopulmonary reserve assessed 
– Assess Hb and refer to Anaemia Recommendations  

– ABG results on the ground and at rest are not reliable for predicting desaturation during flight (7)  		– Supplemental O2 
– Medical escort with scope to titrate O2 according to COPD severity, administer nebulisation 
– Consider lie-flat seating  
– Refer to universal respiratory guidelines  
Acute exacerbation of pulmonary fibrosis or first diagnosis – Assess Hb and refer to Anaemia Recommendations 
– Hb > 5,3 mmol/L (8,5 g/dL) (4,5,9) 
– < 2 min/L continuous O2  
– Mobilizing 
– Cardiopulmonary reserve assessed 
– Cardiac comorbidities controlled 
– Underlying trigger resolved – see LRTI guidelines if applicable  		– Supplemental O2 
– Medical escort with scope to titrate O2 
– Consider PRC transfusion if Hb < 5,3 mmol/L (8,5 g/dL) (4,5,9) 
– Refer to universal respiratory guidelines   
Asthma No admission 
– returned to clinical baseline  
 
 		 – FTF with no restrictions 
– Carry MDI in hand luggage 
– Refer to universal respiratory guidelines  
Ward Admission 
– Treatment complete 
– Underlying trigger resolved; see relevant section if applicable 
– 5 days after oxygen therapy is discontinued 
– Cardiopulmonary reserve assessed  		 – Carry MDI in hand luggage 
– Individualise need for nebuliser Medical escort with scope to administer nebulisation required 
ICU Admission with NIV / IPPV 
– Treatment complete 
– Underlying trigger resolved; see relevant section if applicable 
– 5 days after oxygen therapy discontinued 
– Cardiopulmonary reserve assessed  		– Supplemental O2 
– MDI in hand luggage 
– Medical escort with scope administer nebulisation required  
– Refer to universal respiratory guidelines 
Cystic Lung Diseases  Individualise based on:  
– Size of cyst/s  
– Number of cyst/s 
– Location of cyst/s  
– Wall thickness of large cyst/s 
– Communication with normal lung tissue / bonchioli (5)  		– Large intraparenchymal lesions are a relative contra-indication to fly 
– Medical escort with scope to manage a pneumothorax 
– Refer to universal respiratory guidelines  
Lower Respiratory Tract Infections (LRTI) Managed with Low Flow O2 
– O2 discontinued 
– 5 days after starting appropriate antibiotics 
– Mobilizing 
– Underlying pulmonary comorbidities controlled; see relevant section if applicable 
– Cardiopulmonary reserve assessed   		– Stable patients with sufficient cardiopulmonary reserve may be flown with a short line to bolus antibiotic dosing 
– Individualise O2 supplementation 
– Medical escort with scope to titrate O2, and administer IV antibiotics 
– Refer to universal respiratory guidelines 
Managed with High Flow O2 / NIV / IPPV 
– Care downgraded to general ward 
– < 2 min/L continuous O2 
– Acute treatment complete 
– Mucous production self-cleared 
– Underlying pulmonary comorbidities controlled; see relevant section if applicable 
– Mobilizing 
– Cardiopulmonary reserve assessed  		– Supplemental O2 
– Medical escort with scope to titrate O2 
– Lie-flat seating  
– Refer to universal respiratory guidelines  
Lung Cancer / Space Occupying Lesions – Individualise based on burden of pulmonary parenchymal involvement and systemic involvement 
– Assess Hb and refer to Anaemia Recommendations  

– Hb > 5,3 mmol/L (8,5 g/dl) (4,5,9) 
– Electrolytes within normal ranges; Ca2+, Na+, K+ 
– O2 < 2L/min continuous flow 
– No major haemoptysis; defined as life threatening, large and rapid bleed   		– Consider PRC transfusion if Hb < 5,3 mmol/L (8,5 g/dL) (4,5,9) 
– Pleural effusion drained prior to departure (take into consideration rate of reaccumulation) 
– Supplemental O2 
– Medical escort with scope to drain pleural effusion and titrate O2 therapy 
– Lie flat seating  
Pleural Effusion – Drains removed 
– No pneumothorax 
– O2 < 2 L/min on ground 
– Assess the rate of reaccumulation 
– Consider other system involvement (e.g. malignancy) 
– Cardiopulmonary reserve assessed  

Infectious aetiology  
– Completed 5 days of appropriate antimicrobials; see relevant section if applicable  

Non-infectious aetiology 
rate of reaccumulation must not cause respiratory distress during travels  		– Supplemental O2 
– Medical escort to titrate O2 therapy with scope to manage a pleural effusion  
– Refer to universal respiratory guidelines  
Pulmonary Hypertension – Evaluate underlying cause of pulmonary hypertension, refer to corresponding section 
– Cardiac echo does not show right ventricular strain  

– Beware at altitude there is pulmonary vasoconstriction which will impact on RV function   		– Individualise FTF 
– No RV strain 
– Refer to universal respiratory guidelines  
Pulmonary Tuberculosis – Assess aetiology of immune compromise  
– Refer to corresponding section if applicable 
 
Drug sensitive TB  
– 2 weeks of appropriate medication  
Multi-drug Resistant / Extensive Drug Resistant / Totally Drug Resistance TB 
– only once 2 consecutive negative sputum tests have been returned  		– Patient to wear surgical mask 
– Refer to universal respiratory guidelines  
Spontaneous Pneumothorax (excluding trauma) (4,5) – Underlying cause controlled / resolved 
– ICD removed 
– 7 days after pneumothorax resolution on CXR 
– Mobilizing 
– No super added infection 
– No further surgical intervention required 
– Cardiopulmonary reserve assessed  		– If flying < 7days after radiological resolution, consider medical escort and O2 
– Individualise O2  
– Medical escort to titrate O2 therapy with scope to manage pneumothorax 
– Refer to universal respiratory guidelines  
Thoracotomy (4,5) – No post-operative complications 
– Treatment complete 
– < 2 L/min continuous O2 
– Mobilizing 
– Cardiopulmonary reserve assessed 
– 10 days after no intrathoracic free air on CXR  		– Supplemental O2 
– Lie-flat seating  
– Medical escort to titrate O2 therapy with scope to manage pneumothorax 
– Refer to universal respiratory guidelines  
Video Assisted Thoracoscope (VATS) – Uncomplicated procedure 
– No post-operative complications 
– Mobilizing 
– Cardiopulmonary reserve assessed  		– Individualise O2  
– Medical escort to titrate O2 therapy with scope to manage pneumothorax 
– Lie-flat seating  
– Refer to universal respiratory guidelines  

References

  1. Ahmendzai, S. Balfour-Lynn, M. Bewick, T. Buchdahl, R. Coker, RK. (2011). Managing Passengers with Stable Respiratory Disease Planning Air Travel: British Thoracic Society recommendations. Thorax An International Journal of Respiratory Medicine. Journal of the British Thoracic Society. Volume 66 Supplement September 2011. ISSN 0040-6376 (print) ISSN 1468-3296 (online)  
  2. Chen Y, Almirall-Sánchez A, Mockler D, Adrion E, Domínguez-Vivero C, Romero-Ortuño R. (2022) Hospital-associated Deconditioning: Not only physical, but also cognitive. Int J Geriatr Psychiatry. 2022 Mar;37(3):10.1002/gps.5687. doi: 10.1002/gps.5687. PMID: 35142397; PMCID: PMC9303382.  
  3. Okyay, K. (2021). Systemic Arterial Hypertension and Flight. Anatol J Cardiol. 2021; 25(Suppl 1): S7-S9. Published 2021 Aug 1. Available from doi: 10.5152/Anatol JCardiol.2021.S104  
  4. Chang, D. (2013). What are the indications for a blood transfusion? The Hospitalist. Society of hospital Medicine. September 1, 2013. Available from https://www.the-hospitalist.org/hospitalist/article/125662/what-are-indications-blood-transfusion 
  5. Tanimura,M. Dohi,K. Fujimoto, N. Moriwaki, K. Omori, T. et al. (2017) Effect of Anemia on Cardiovascular Hemodynamics, Therapeutic Strategy and Clinical Outcomes in Patients With Heart Failure and Hemodynamic Congestion. Circulation Journal Volume 81 Issue 11 Pages 1670-1677 https://doi.org/10.1253/ 
  6. Josephs LK, Coker RK, Thomas M; BTS Air Travel Working Group; British Thoracic Society. Managing patients with stable respiratory disease planning air travel: a primary care summary of the British Thoracic Society recommendations. Prim Care Respir J. 2013 Jun;22(2):234-8. doi: 10.4104/pcrj.2013.00046. PMID: 23732637; PMCID: PMC6442792. 
  7. Ergan, B. Akgun, M. Pacilli, AMG. Nava, S. Should I stay or should I go? COPD and Air Travel. Eur Respir Rev 2018; 27: 180030 [https://doi.org/10.1183/16000617.0030-2018].
  8. Singh A, Avula A, Zahn E. Acute Bronchitis. [Updated 2024 Mar 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448067/ 
  9. Choi H, Chalmers JD. Bronchiectasis exacerbation: a narrative review of causes, risk factors, management and prevention. Ann Transl Med. 2023 Jan 15;11(1):25. doi: 10.21037/atm-22-3437. Epub 2022 Nov 16. PMID: 36760239; PMCID: PMC9906191. 
     
    Additional Sources 
    i.Coker, RK. Armstrong, A. Church, AC. et al.. BTS Clinical Statement on air travel for passengers with respiratory disease. BMJ Journals 2021 Volume 77, Issue 4. https://doi.org/10,1136/thoraxjnl-2021-218110 
     
    ii. Tzani, P. Pisi, G. Aiello, M. et al. Flying with Respiratory Care. Respiration (2010) 80(2): 161-171. Available from https://doi.org/10.1159/000313425 
     
    iii. Nicholson, TT. Sznajder, JI. Fitness to Fly in Patients with Lung Disease. Annals of the American Thoracic Society. 2014 Volume 11, Issue 10. https://doi.org/10.1513/AnnalsATS.201406-234PS 
     
    iv. Bellinghausen, AL. Mandel, J. Assessing Patients for Air Travel. Chest 2021 May; 159(5): 1961-1967. Published online 2020 Nov Available from: 10.1016/j.chest.2020.11.002 
     
    v. Powel-Dunford, N. Adams, JR. Medical Advice for Commercial Air Travel. American Academy of Family Physicians October 2021. Volume 104, Number 4 
     
    vi. Raoof, S. Bondalapati, P. Vydyula, R. Et al. Cystic Lung Diseases. Chest 2016 Oct; 150(4): 945-965. Published online 2016 May 13. Available from doi: 10.1016/j.chest2016.04.026 
     
    vii. Chetta, Alfredo & Castagnetti, Claudia & Marina, Aiello & Sergio, Francesco & Fabiano, Nicola & Tzani, Panagiota & Marangio, Emilio & Olivieri, Dario. (2007). Walking capacity and fitness to fly in patients with chronic respiratory disease. Aviation, space, and environmental medicine. 78. 789-92. Abstract available from https://pubmed.ncbi.nlm.nih.gov/1776 
     
    viii. American Thoracic Society ATS Statement: guidelines for the Six-Minute Walk Test. March 2002. American Journal of Respiratory and Critical Care Medicine, Volume 166, Issue 1. Available from https://doi.org/10.1164/ajrccm.166.1.at1102 
      
Neurological System

Kay, S. Hosea, G.  Marrel, J. Hulzebosch, A.  Blake, H. Nathan, M.   Correspondence: medical@netiag.com 
  • Consult general recommendations for fit-to-fly. 
  • Consult other organ systems for patients with multiple diagnoses. 
  • Consult other organ systems for patients with multiple comorbidities.  
  • Consider the longest delay for a safe departure for patients following a complicated course of illness.  

      Physiological Considerations Relevant to the Neurological System  

      • Raised intracranial pressure is a relative contradiction to commercial flight.  FTF is dependent on chronicity, aetiology, and clinical condition of the patient.  Consult with the treating neurologist.  
      • Pneumocephalus is a relative contradiction to commercial flight – FTF depends on the volume of free air. 
      • Evidence shows a pneumocephalus volume < 11ml is safe to fly commercially. (8) 
      • Cerebral perfusion pressure is auto regulated.  With prolonged exposure to a hypobaric hypoxic environment, cerebral blood flow increases, which can increase raised intracranial pressure. (4) 
      • An internal CSF shunt is not a contra-indication to commercial flight. (1)  The shunt must not be obstructed. 
      • Patients with a ventriculoperitoneal (VP) or lumboperitoneal (LP) shunt should obtain additional specialist evaluation as pressure changes could impact on shunt functioning, thus impacting on raised intracranial pressure. (17)  
      • When cerebral oxygen demand outstrips supply, cerebral oedema may arise. (4)  
      • Travelling by air lowers the seizure threshold.  The patient is exposed to multiple triggers, a breakthrough seizure may occur. (3) 
      • Sleep deprivation is a major trigger for breakthrough seizures.  Epileptics should aim to obtain normal / near normal sleep while travelling. (3) 
      • Changes in time zones must be factored when taking chronic medications for neurological conditions. 
               Universal Guidelines for Patients flying with / after an Acute Neurological Insult 
      Recommendation Patient / Member 
      WCHS  – All patients   
      Graded compression stockings   – All patients  
      Supplemental O2  – Patients with cardiopulmonary comorbidities 
      – Disease / condition complicated by raised intracranial pressure during admission    
      Medical escort – Supplemental O2 
      – Monitoring swallowing with prevention of aspiration 
      – Recent tracheostomy requiring care 
      – Patient flying before recommended fit-to-fly date  
      Seating with additional leg room  – Supplemental O2  
      – Medical escort  
      – Accidental injury may occur if patient seated in a confined space 
      – Patients with mild cognitive impairment   
      Lie-flat seating – Hospital-Associated-Decompensation 
      – Poor cardiorespiratory reserve  
      – Patients with 3 – 4 / 5 power muscle in upper / lower limbs 
      – Supplemental O2  
      – Medical escort 
      – Immediate post-operative phase  
      Stretcher – Extensive neurological fallout 
      – Spinal fractures 
      – Post spinal column surgery 
      – Pelvic fractures – unstable / ORIF performed   
      Non-medical escort – Unable to complete activities of daily living 
      – Patients with mild cognitive impairment 
      – Patients with communication fallout (aphasia / dysarthria)  
         Recommendations for Specific Neurological Conditions  
      Condition  Assessment  Recommendation  
      Cerebral tumor/s or space occupying lesion Solid Mass, Non-Haemorrhagic 
      – No clinical evidence of raised intracranial pressure 
      – Condition stable or improving       		– Minimum of 5 days after stabilisation 
      – Individualise seating according to patient 
      – Individualise medical escort according to clinical condition  
      Solid Mass, Haemorrhagic 
      – No clinical evidence of raised intracranial pressure 
      – Bleeding controlled and clinically stable        		– 14 days after bleeding controlled 
      – If treated surgically refer to neurosurgery section 
      – Individualise seating according to patient 
      – Individualise medical escort according to clinical condition  
      CVA – Haemorrhagic Minimal Residual Effects 
      – Appropriate workup completed 
      – Aetiology identified and treated appropriately 
      – No signs of raised intracranial pressure 
      – Oral anti-hypertensives started if appropriate        		– At least 4 days after diagnosis 
      – Individualise non-medical escort depending on the patient’s ability to complete activities of daily living 
      CVA – Haemorrhagic Continued Clinically Significant Residual Effects 
      – No further neurological decline 
      – Appropriate workup completed 
      – Aetiology identified and treated appropriately 
      – Clotting profile within normal limits 
      – No signs of raised intracranial pressure 
      – Oral anti-hypertensives started if appropriate         		– 7 days after diagnosis 
      – Individualise supplemental O2 according to cardiopulmonary comorbidities 
      – Individual seating position according to clinical condition 
      – Individualise medical escort according to residual fallout, escort capable of monitoring vital signs and administering O2  
      Severe Residual Effects 
      – No further neurological decline 
      – Other systems stable 
      – Appropriate workup completed 
      – Aetiology identified and treated appropriately 
      – Clotting profile within normal limits 
      – No signs of raised intracranial pressure 
      – Oral anti-hypertensives started if appropriate        		– 14 days after diagnosis 
      – Individual position according to clinical condition (stretcher / AA)    
      CVA – Ischemia Minimal Residual Effects 
      – Appropriate workup completed 
      – Aetiology identified and treated appropriately 
      – No signs of raised intracranial pressure 
      – Started oral secondary stroke prevention medication        		– At least 2 days after diagnosis 
      – Refer to relevant sections if aetiology is confirmed (e.g. AF) 
      Clinically Significant Residual Effects 
      – Appropriate workup completed 
      – Aetiology identified and treated appropriately 
      – No signs of raised intracranial pressure 
      – No further neurological decline 
      – Started oral secondary stroke prevention medication        		– 7 days after diagnosis 
      – Refer to relevant sections if aetiology is confirmed (e.g. AF) 
      – Individualise seating position according to clinical deficit 
      – Individualise supplemental O2 according to cardiopulmonary comorbidities 
      – Individualise medical escort according to O2 requirements.  Escort capable of monitoring vital signs and administering O2  
       Clinically Severe Residual Effects
      – Appropriate workup completed 
      – Aetiology identified and treated appropriately 
      – No signs of raised intracranial pressure 
      – No further neurological decline 
      – Started oral secondary stroke prevention medication        		– 14 days after diagnosis 
      – Refer to relevant sections if aetiology is confirmed (e.g. AF) 
      – Individualise seating position according to clinical deficit 
      – Stretcher / AA if deficit includes artificial ventilation  
      TIA – Appropriate workup completed 
      – Aetiology identified and treated appropriately 
      – Prescribed oral secondary stroke prevention medication        		– At least 2 days after diagnosis 
      – Refer to relevant sections if aetiology is confirmed (e.g. AF) 
      Dementia – Appropriate workup to exclude acute infectious process 
      – Appropriate workup for psychiatric disorder completed 
      – Mild cognitive impairment only 
      – No aggression / agitation 
      – Locus of control intact        		– Refer to psychiatric conditions for further recommendations 
      – Individualise seating position dependent on state need to sleep / mild sedation 
      – As per flight schedule 
      – Non-medical escort  
      Epilepsy / Seizures General recommendations for seizures: 
      – Optimise medication compliance with time zone changes.  
      – Optimise environmental triggers characteristic of air travel. (3,5)   
      – Optimise sleep on long haul flights. (3,5)   
      – Individualise supplemental oxygen for patients with cardiopulmonary comorbidities. (3) 
      – Consider prophylactic oral benzodiazepines prior to travel.  The following medications are recommended clonzepam, lorazepam, diazepam. (6) Medication must be taken as advised by the local treating medical doctor.  
      First Seizure/s 
      – Cardiac comorbidities at baseline 
      – No longer infectious 
      – 4 days after completing treatment  
      – Cardiopulmonary reserve assessed        		– No seizures or neurological symptom/s for 3 consecutive days 
      – Lying position to facilitate maximal sleep 
      – Medical escort with scope to manage seizures  
      Breakthrough Seizure/s 
      – Likely trigger identified and corrected 
      – Appropriate workup if required (cases other than poor-compliance etc.) 
      – No new neurological symptoms        		– No seizures for 2 consecutive days 
      – Lying position to facilitate maximal sleep 
      Guillen Barré Syndrome – Appropriate work up completed 
      – Symptoms stabilized, no further progression 
      – No respiratory muscle involvement        		– 1 week after stabilization 
      – Individualise: 
      – seating position according to clinical condition 
      – medical escort according to clinical condition  
      – non-medical escort according to ability to perform activities of daily living  
      Meningitis – Completed treatment 
      – No signs of raised intracranial pressure  
      – Mobilising       		– As per flight schedule 
      – Assess cardiopulmonary reserve 
      – Individualise seating according to clinical condition 
      – Individualise medical escort according to clinical condition 
      – If travelling before completing IV antimicrobials, patient must be afebrile with evidence of downward trend of infective markers.  Medical escort with scope to administer IV therapy  
      Non-traumatic Subarachnoid Haemorrhage – Management complete 
      – No signs of raised raised intracranial pressure 
      – Blood pressure stable  
      – Taking oral antihypertensives if appropriate 
      – No seizures / seizures controlled 
      – Cognitive state stable 
      – Mobilising 
      – Cerebral vasospasm resolved        		– If haemorrhage managed surgically, refer to neurosurgical section 
      – 14 days after haemorrhage controlled / stabilized 
      – Lying position 
      – Medical escort with scope of practice to monitor vital signs, control BP and administer therapeutic O2  

      1. Righospitalet, Copenhagen University Hospital, Danish Aeronautical Medical Association, SOS International.  Central Nervous system Disorders.  Air Travel and Transportation of Patients a guide for physicians.  2020  Available from https://dfdms.dk/ 


      2. Trevorrow, T.  Air travel and seizure frequency for individuals with epilepsy.  Seizure (2006) 15, 320 – 327 Chaminade University of Honolulu, Behavioural Science.  https://www.sciencedirect.com/science/article/pii/S1059131106000616 

      3. Rands, G.  McCabe, T.  Imray, C.  Post-flight confusion: does flying affect the brain?  BJPSYCH INTERNATIONAL Volume 17 Number 3. August 2020 https://pmc.ncbi.nlm.nih.gov/articles/PMC8281225/ 
       
      4. Biller, A.  Badde, S.  Heckel, S.  Exposure to 16h of normobaric hypoxia induces ionic edema in the healthy brain.  Nature Communications.  (2021) 12:5987 https://doi.org/10.1038/s4167-021-26116-y 
       
      5. 
      Devkota, AR.  Karki, AR.  Seizure precipitated during long haul flight.  Journal of Institute of Medicine, December, 2010; 32:3 59-61 https://jiomnepal.edu.np/index.php/jiomnepal/article/download/528/499/988 
       
      6. 
      Beran RG. Use of Interval Therapy with Benzodiazepines to Prevent Seizure Recurrence in Stressful Situations. Brain Sci. 2022 Apr 19;12(5):512. doi: 10.3390/brainsci12050512. PMID: 35624899; PMCID: PMC9138519. 
       
      7. 
      Tariq, A.  Aquilar-Salinas, P et al.  The role of ICP monitoring.  JNS Journal of Neurosurgery. 2017 Volume 43: Issue 5.  Available from https://doi.org/10.3171/2017.8.FOCUS17419 
       
      8. 
      Brandstrom et al.  Risk for intracranial pressure increase related to enclosed air in post-craniotomy patients during air ambulance transport: a retrospective cohort study with simulation.  Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2017) 25:50 DOI 10.1186/s13049-017-0394-9 
       
      9. 
      Hoiland, RL.  Bain, AR.  Reiger, MG.  Hypoxaemia, oxygen content, and regulation of cerebral blood flow.  2016 Americal Journal of Physiology-Regulatory, Integrative and Comparative Physiology 310:5, R398-R413 
       
      10. 
      Falla, M.  Giardini, G.  Angelini, C.  Recommendations for traveling to altitude with neurological disorders.  2021.  Journal of Central Nervious System Disease Volume 13: 1 – 18  DOI 10.1177/11795735211053448 
       
      11. 
      St George, D.  Gray, B.  Steenberg, M.  Transferring Fixed Wing Air Medical Patients with Intracranial Haemorrhages.  2020 Air Medical Journal 39(2020) 249 – 250.  DOI 10.1016/j.amj.2020.04.018 
       
      12. 
      Phillips, M., Saria, M., Eisenberg, A. et al. Safety of commercial airflight in patients with brain tumors: a case series. J Neurooncol 139, 617–623 (2018). https://doi.org/10.1007/s11060-018-2905-6 
       
      13. 
      Pinto VL, Tadi P, Adeyinka A. Increased Intracranial Pressure. [Updated 2023 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482119/ 
       
      14. 
      Leonhard, S.E., Mandarakas, M.R., Gondim, F.A.A. et al. Diagnosis and management of Guillain–Barré syndrome in ten steps. Nat Rev Neurol 15, 671–683 (2019). https://doi.org/10.1038/s41582-019-0250-9 
       
      15. 
      Amin, HP.  Madesen, TE.  Bravata, DM.  Diagnosis, workup, risk reduction of transient ischemic attack in the emergency department setting: a scientific statement from the American Heart Association.  March 2023.  Stroke Volume 54, Issue 3, March 2023; Pages e109-e121.  https://doi.org/10.1161/STR.0000000000000418 
       
      16. 
      British Airways Health Services.  Your patient and air travel.  A guide to physicians.   Available from https://www.britishairways.com/health/docs/before/airtravel_guide.pdf 
       
      17. 
      Goldemund, D.  Air travel considerations after a stroke.  Stroke Manual.  Published 19/09/2024 Available from https://www.stroke-manual.com/air-travel-considerations-after-stroke/  Last visited December 2024 
       
      18. 
      Alvarez-Velasco, R.  Masjuan, J.  DeFelipe, A.  Stroke in Commercial Flights.  AHA / ASA Journals.  Stroke  Volume 47, Number 4.  2024  Originally published 18 February 2016.  Pg 1117 – 1119 http://stroke.ahajournals.org/ 
      Other Resources  
      i. 
      Aerospace Medical Association.  Medical Guidelines for Airline Travel 
      Available from: https://www.asma.org/publications/medical-publications-for-airline-travel 
       
      ii. 
      IATA Medical Manual Edition 12 July 2020 
      Available from: https://www.iata.org/en/publications/medical-manual/ 
       
      iii. 
      International Assistance Group.  Fitness to Fly Guideline October 2015 
       
      iv. 
      OMAR Guidelines Indications and Requirements of patients transportation by air 2023 
      Available from: https://omar.nl/?lang=en 
       

      Recreational Diving and Decompression Illness
      Sharon Kay Correspondence: medical@netiag.com 
      • These guidelines refer to recreational diving only. 
      • All information and considerations for FTF are taken directly from the DAN Guidelines. 
      • Other documents published by DAN have been considered. 
      • Important resources:  
        1. DAN Health and Medicine https://dan.org/health-medicine/ 
        2. Undersea and Hyperbaric Medical Society Chamber Directory https://www.uhms.org/resources/other-links/chamber-directory.html 
      • Consider and combine guidelines relevant to patient comorbidities. 
      • Consider the longest delay for safe departure in divers with complications. 

      Pathophysiological Factors at play in Recreational Diving Injuries 

      • Symptoms of decompression illness (DCI) most often present within 24 hours of resurfacing.  The earlier the presentation, the worse the pathology and clinical course. (1) 
      • Flying in a commercial aircraft before the recommended rest period can increase the diver’s risk of developing DCI in- or post-flight. (2) 
      • At cruising altitude, the cabin is a hypobaric hypoxic environment, passengers will be breathing the equivalent of FiO2 0,15 at sea level.  Consider supplemental O2.  
               Definitions of Diving Injuries 
      Condition Definition 
      Decompression Illness (DCI) (3) – DCI is divided into 2 diseases 
      1. Decompression Sickness (DCS) 
      2. Arterial Gas Embolism (AGE) 
      – Management 
      – Conservative – symptoms resolve spontaneously 
      – Admission to medical facility for low flow O2 therapy 
      – Admission to medical facility for hyperbaric chamber sessions 
      – FTF depends on the severity, management, and course of illness  
      Decompression Sickness (DCS) (3) – “A potentially life-threatening condition that occurs when dissolved gases (commonly nitrogen) form bubbles in the bloodstream and tissues.” (11) 
      – Also known as “The Bends” 
      – Typically develops within 24 hours of resurfacing 
      – Can develop in- or post-flight if a diver flies too soon after diving 
      – Signs and symptoms may be (but not limited to) joint pain, skin itch, dizziness, muscle weakness, confusion  
      Arterial Gas Embolism (AGE) (4) – Medical emergency when nitrogen enters the arterial blood system.   
      – Gas emboli lodge in arterioles / capillaries causing a reduction of blood flow to organs and peripheral tissues 
      – May develop signs / symptoms while still underwater 
      – Typically signs and symptoms develop within 15 min of resurfacing 
      – Presentation may be (but not limited to) loss of consciousness, confusion, seizures, pulmonary oedema, weakness, or paralysis  
      – Emergency evacuation to hyperbaric chamber is essential  
      Universal Guidelines for Divers Flying after a Recreational Diving Injury 
      Recommendation Diver 
      Supplemental O2 – O2 required on the ground 
      – Unable to complete 50m Walk Test 
      – Significant pulmonary comorbidities 
      – Anaemia (Hb < 5,3 mmol/L or 8,5 g/dL) 
      – Venous thromboembolism  
      Additional leg room – Supplemental O2 in-flight 
      – Medical escort  
      Lie-flat seating – Supplemental O2 in-flight 
      – Prolonged upright seating may be detrimental to recovery / acute medical condition 
      – Medical escort 
      – HAD  
      Stretcher  Significant neurological fallout – paralysis  
      Medical escort – Supplemental O2 in-flight  
      – Diver returning before recommended FTF date 
      Non-medical escort  HAD  
      Fitness to Fly after Diving and Decompression Illness 
      Recreational Diving without Complication/s 
      Dive Pattern Recommendation 
      Single dive – Minimum of 12 hours after resurfacing 
      – Recommend more than 24 hours  
      Multiple dives per day or Multiple consecutive days diving  – Minimum of 18 hours after resurfacing 
      – Recommend more than 36 hours 
      Dives requiring decompression stops  – Minimum of 48 hours after resurfacing 
         Decompression Illnesses 
      Dive Injury Recommendation 
      Decompression Sickness  – Minimum of 72 hours after fully recovered or  
      – Minimum of 72 hours after last hyperbaric chamber session 
      Arterial Gas Embolism – Minimum of 1 week after last hyperbaric chamber session 
      – Consider other organ system recommendations should there be ongoing dysfunction  

      References

      1. Danish Aviation and Diving Medical Company. Air Travel and transportation of Patients 2024. Available from https://aeromedicalguidelines.com/   
      2. Feldman J, Cooper JS. Flying After Diving. [Updated 2023 Nov 23]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499855/ 
      3. Thalmann, E. Divers Alert Network. Decompression Illness. Available from https://dan.org/health-medicine/health-resources/diseases-conditions/decompression-illness-what-is-it-and-what-is-the-treatment/  Last visited September 2024  
      4. Divers Alert Network 2020 How to Avoid Rapid Ascents and Arterial Gas Embolism.  August 4, 2020.  Available from https://dan.org/safety-prevention/diver-safety/divers-blog/how-to-avoid-rapid-ascents-and-arterial-gas-embolism/  Last visited September 2024  
         
      Abbreviations
      Sharon Kay Correspondence: medical@netiag.com 
      Abbreviation  
      > Greater than 
      < Less than 
      AA Air Ambulance 
      ABG Arterial Blood Gas 
      BP Blood Pressure 
      DAN Divers Alert Network 
      CABG Coronary Artery Bypass Graft 
      CN Cranial Nerve 
      COAD Chronic Obstruction Airways Disease 
      COPD Chronic Obstructive Pulmonary Disease 
      CSF Cerebrospinal Fluid 
      CXR Chest X-ray 
      DVT Deep Vein Thrombosis 
      ECG Electrocardiogram 
      FEV1 Forced Expiratory Volume exhaled within the first second  
      FTF Fit-to-Fly 
      HAD Hospital-Associated Deconditioning 
      Hb Hemoglobin 
      HR Heart Rate 
      INR International Normalized Ratio 
      LMWH Low Molecular Weight Heparin 
      LRTI Lower Respiratory Tract Infection 
      LV Left Ventricle 
      LVEF Left Ventricular Ejection Fraction 
      MV Minute Volume 
      NOAC Non-vitamin K oral antagonist anticoagulant 
      NSTEMI Non-ST-Elevation Myocardial Infarction 
      PaO2 Partial Pressure of Oxygen 
      PAU Patient Assist Unit 
      PDA        Patent Ductus Arteriosus 
      PFO Patent Foramen Ovale 
      PE Pulmonary Embolism 
      O2 Oxygen 
      ROSC Return of Spontaneous Circulation 
      RR Respiratory Rate 
      RV Right Ventricle 
      Sats / SpO2 Oxygen saturation  
      STEMI ST-Elevation Myocardial Infarction 
      TV Tidal Volume 
      VSD Ventricular Septal Defect 
      WCOB Wheelchair assistance on board aircraft  Patient unable to walk; consider stretcher 
      WCHC Wheelchair assistance to aircraft seat   Patient unable to walk; consider stretcher 
      WCHS Wheelchair assistance to aircraft door   Patient unable to climb stairs 
      WCHR Wheelchair assistance to boarding ramp  Patients able to climb stairs