A Concise Guide to Current in-Flight Medical Incidents

Lack of oxygen and legroom can cause serious health problems. Farrol Kahn explains the issues

The era of ever longer non-stop flights could herald a dramatic increase in in-flight medical incidents, a situation already considered by the airline which has installed body lockers in their Airbus fleet.

Medical experts are concerned about the impact on the body of long, unbroken flights where passengers breathe a mix of outside and recycled air and up to 25 per cent less oxygen. As the cabin environment has a low relative humidity of 2-20 per cent, viral infections such as colds and flu tend to proliferate.

Travelling greater distances is a significant contributing risk factor for pulmonary embolism in air transport. In one study, 91 per cent of passengers who died from pulmonary embolism were in flight for more than 18 hours. The US National Research Council in its report, the Airliner Cabin Environment and the Health of Passengers and Crew (2002), expressed great concern about the serious health effects on passengers with cardiorespiratory disease and infants, due to reduced oxygen pressure. Another major concern was the respiratory irritant, ozone.

Care shortfall

The recent BMA report on passenger health, ‘Impact on Flying’, highlighted the lack of medical care for air travellers.

Better in-flight medical equipment and improved staff training in emergency care were required.

British Airways, which carried 36 million passengers in 1997-8, had an incident rate of one in 12,000 passengers while Virgin had a higher rate of one in 1,400, with 3.6 million passengers (1999). Some 19 per cent of the BA incidents were cardiovascular, including heart attack and stroke, and there were 10 deaths a year. The main condition on Virgin was disorder of circulation, accounting for 39 per cent of all incidents.

In another study carried out by the Federal Aviation Administration into 1,132 in-flight medical incidents (1996-1997), it was found that although vasovagal syncope occurred with the greatest frequency, the most common categories of in-flight medical incidents were cardiac (20 per cent),neurological (12 percent) and respiratory (8 per cent).

The number of doctors responding to medical incidents varied from 8 to 85 per cent. Such a varied response in spite of the protection from defence societies reveals an inherent caution.This is something that the airlines should try to overcome. They should inform GPs of the contents of medical kits, supply them with a standard form and pay them an honorarium for attendance. About 47 per cent of the patients from diverted flights were admitted to hospital.

The most common cause of death was cardiac (80 per cent) followed by pre-existing medical conditions. A Qantas airline study listed MI as the leading cause of in-flight death, followed by cerebral vascular accident.

Flight conditions could be improved by the reduction of the cabin altitude to 6,000ft as is now being proposed in the new Boeing 7E7.The return to 100 per cent fresh air in-flight and a doctor’s presence on all ultra-long-haul flights will also help.

Medical clearance

GPs should obtain medical clearance for passengers with pre- existing conditions from airline medical departments. Another measure is for airlines to publish medical in-flight incidents in peer-reviewed journals, which will give the medical profession accurate data.

GPs should advise patients that there are health risks in air travel because of the pressurized cabin. Most people are fit to fly. An unfit passenger is anyone who has a disease that impairs cardiac output, the lung’s ability to oxygenate blood, the flow of blood through the circulatory system, the blood’s oxygen carrying capacity, or who has blood that might clot easily.

A comprehensive GP guide can be found on the AHI website www.aviation-health.org under the Medical Centre for Health Professionals.

At risk: 91 per cent of passengers who died from pulmonary embolism were in flight for more than 18 hours

Which patients mayfly and when

Patients may fly with:

* Ml – wait until three weeks have elapsed and normal activities have been resumed. A symptom-linked treadmill test is prudent. In the US travel after 10-14 days has been recently allowed.

* Complicated Ml – wait until stable on treatment.

* Coronary artery bypass graft and other chest surgery – wait about two weeks so that any air introduced into the chest will have been absorbed. Confirm the condition is stable with no congestive cardiac failure, serious arrhythmia or ischaemia.

* Percutaneous transluminal coronary angioplasty – when stable and back to usual daily activities.

Patients should not fly with:

* Severe congestive cardiac failure.

* Unstable angina or uncontrolled arrhythmias.

* Decompensated major valvular disease, congenital heart disease, and cardiomyopathy.

* Uncontrolled severe hypertension.

* Eisenmenger syndrome (pulmonary hypertension).

Source: Aviation Health Institute

Mr Kahn is director of the Aviation Health Institute

Copyright Haymarket Business Publications Ltd. Oct 8, 2004