Guide for General Practitioners.

(1) Cardiovascular Disease.

A		Myocardial Infarction - until 3 weeks have elapsed and normal activities have been resumed. Symptom-linked treadmill test prudent. (Lately in USA travel after 10-14 days has been allowed without incident) (1).
B		Complicated myocardial infarction - wait till stable on treatment.
C		Coronary artery bypass graft and other chest surgery - wait about 2 weeks so that any air introduced into chest will have become absorbed. (Examine before travel to confirm condition stable with no congestive cardiac failure, serious arrhythmia or ischaemia).
D		Percutaneous transluminal coronary angioplasty - until stable and back to usual daily activities.
E		Severe congestive cardiac failure.
F		Unstable angina or uncontrolled arrhythmias.
G		Decompensated major valvular disease, congenital heart disease, and cardiomyopathy.
H		Uncontrolled severe hypertension.
I		Eisenmenger Syndrome.

(2) Central Nervous System and Psychiatric Disorders.

A		Stroke - until convalescence completed.
B		Poorly controlled disorders including epilepsy
C		Active psychosis

(3) Respiratory System.

A		Asthma - where labile, severe, or hospitalisation recently required.
B		Pneumothorax - (risk of tension pneumothorax) - until 2-3 weeks after successful drainage or surgery.
C		Pneumomediastinum, subcutaneous emphysema (marker of extra-alveolar air).
D		Pleural Effusion.
E		Active or contagious chest infections, including active tuberculosis until documented control (negative cultures) and clinical improvement.
F		Severe chronic obstructive airways disease and other pulmonary disease with hypoxia - prior assessment with pulmonary function tests and blood gas analysis required.
G		Lung cysts and bullae - unless connected with airways.

(4) ENT.

A		Surgery involving opening of inner ear e.g. stapedectomy (risk of perilymph fistula) - most surgeons advise wait at least 2 weeks (2).
B		Middle ear effusions and infections, and acute sinusitis, until resolved.

(5) Following Surgery involving introduction of Air or Gas.

A		e.g. laparoscopy and colonoscopy - till 24 hours elapsed and bloating absent.
B		Surgery for retinal detachment with introduction of gas (for 2 weeks using sulphur hexafluoride, 6 weeks with perfluoropropane).
C		Air introduced into skull incidentally following surgery or trauma: confirm reabsorption by X-ray or scan - or wait at least one week.

(6) Skilled medical attention likely to be urgently needed,

A		Unstable poorly controlled Diabetes.
B		Significant anaemia.
C		Rapidly progressive renal or liver failure.
D		Post-operatively following any major surgery. Post-abdominal surgery patients have relative ileus for several days - risk of tearing suture lines, bleeding, and perforation. Discourage flight for 1-2 weeks (1 week if intestinal lumen not opened)
E		Peripheral vascular surgery in preceding 2 weeks. (Risk of thrombosis affecting graft (3)).

(7) Miscellaneous.

A		After diving: single dives wait 12 hours; allow at least 24 hours after multiple dives or staged decompression..(4).
B		'Ethical' contraindications: patients with infections may be a hazard to fellow passengers. Children with chickenpox may infect susceptible adults - with possibly even fatal results.
C		Delay flying after spinal anaesthetic. (Air may have been introduced. Severe headache has been reported 7 days after spinal anaesthesia possibly from dural leak associated with lowered cabin pressure).
D		Dental abscess (may be associated with gas production).
E		Pregnancy after 36 weeks.

(8) Relative Contraindications.

A		Symptomatic valvular heart disease. Assessment required of symptoms, functional status, left ventricular function and pulmonary hypertension. In-flight oxygen may be required.
B		History of deep vein thrombosis. Recommend frequent leg movement during flight, adequate fluid intake, support stockings, and prophylactic low molecular weight heparin before boarding and after arrival.
C		Chronic obstructive airways disease. Most patients requiring long-term domiciliary oxygen therapy are on flow rates of 1 or 2 l/min. and can be supported comfortably in-flight with flow rates of 4 l/min. which airline companies can usually supply with face masks.
D		Other pulmonary diseases with hypoxia. Pre-flight assessment includes history, physical examination, pulmonary function tests, and blood gas analysis. Abnormal test results call for further consideration and arterial oxygen tension (PaO2) is single most helpful predictor of level in flight. Ground level PaO2 less than 70mm Hg (9.31 kPa) is likely to call for in-flight oxygen. Raised arterial PCO2 indicates poor pulmonary reserve and increased risk even with in-flight oxygen. PaO2 may be measured while breathing a mixture simulating cabin environment at altitude: if PaO2 is less than 55mmHg (7.315 kPa) oxygen is likely to be needed. In practice if passenger can walk 50 yards or climb one flight of stairs without severe dyspnoea, difficulties are unlikely.
E		Asthma is the commonest chronic respiratory disease amongst the travelling public. Important to remind patients to keep their medication, including inhalers and reserve oral steroids, with them in hand luggage.
F		Pulmonary hypertension symptoms may be seriously aggravated in flight.
G		Children with cystic fibrosis are liable to marked oxygen desaturation (<90%) during flight: consider aerosolysed enzyme deoxyribonuclease pre- and in-flight to reduce sputum viscosity, and pulse oximetry to monitor PaO2.

(9) Procedure for Passengers with Medical Problems.

'MEDIF' form (a medical questionnaire on the patient's condition which can be obtained from the airline's medical department) should be completed and returned to the medical department for comment. They will give advice including whether the patient should fly with supplementary oxygen- or not at all.

References:

Recommendations based on Aviation Medicine 1999 Oxford. Butterworth-Heinemann, edited by Ernsting, Nicholson and Rainford, and Medical Guidelines for Air Travel 1996 Aviation, Space, and Environmental Medicine - Vol.67, No. 10,11 - October 1996; and:-

(1) Allen Parmet (personal communication).
(2) Hazell JPW 1983 Ear problems and flying: what should we tell patients? Modern Medicine October 16.
(3) Scurr JH 1999 (personal communication).
(4) Mecklenburg RL 1989 Flying and Diving. Aviation Medicine Quarterly. 3 141-4.

Edited by Gordon Hickish