Background As many as 1000 lives are lost annually from cardiac arrest in commercial aircraft. Ventricular fibrillation (VF), the most common mechanism, can be treated effectively only with prompt defibrillation, whereas the current policy of most airlines is to continue cardiopulmonary resuscitation pending aircraft diversion. The objective of this study was to assess the impact of making semiautomatic external defibrillators (AEDs) available for use on airline passengers with cardiac arrest.
Methods and Results AEDs were installed on international Qantas aircraft and at major terminals, selected crew were trained in their use, and all crew members were trained in cardiopulmonary resuscitation. Supervision was provided by medical volunteers or (remotely) by airline physicians. During a 64-month period, AEDs were used on 109 occasions: 63 times for monitoring an acutely ill passenger and 46 times for cardiac arrest. Twenty-seven episodes of cardiac arrest occurred in aircraft, often (11 of 27 [41%]) unwitnessed, and they were usually (21 of 27 [78%]) associated with asystole or pulseless idioventricular rhythm. All 19 arrests in terminals were witnessed; VF was present in 17 (89%). Overall, defibrillation was initially successful in 21 of 23 cases (91%). Long-term survival from VF was achieved in 26% (2 of 6 in aircraft and 4 of 17 in terminals). The ability to monitor cardiac rhythm aided decisions on diversion, which was avoided in most passengers with asystole or idioventricular rhythm.
Conclusions AEDs in aircraft and terminals, with appropriate crew training, are helpful in the management of cardiac emergencies. Survival from VF is practicable and is comparable with the most effective prehospital ambulance emergency services. Costly aircraft diversions can be avoided in clearly futile situations, enhancing the cost-effectiveness of the program.
VF is the most common mechanism of sudden unexpected death in Western society.1 2 This event frequently is the first manifestation of coronary artery disease.3 VF is eminently treatable with electrical defibrillation. Under ideal circumstances (electrophysiology laboratory), reversion approximates 100%. In the coronary care ward, the occurrence of VF has minimal if any effect on survival.4 In the prehospital setting, successful reversion with long-term survival has been reported in up to 30% in large series.5 Survival from VF is critically dependent on the time from onset to first defibrillatory shock; if the shock is applied within 3 minutes, most patients survive; if the shock delayed beyond 16 minutes, survival rates are minuscule, even with effective CPR.2 6 Death from cardiac arrest in commercial airliners has been underreported in the past,7 8 but as many as 1000 have been estimated to have occurred annually in IATA carriers.8 9 This figure is substantially higher than deaths from crashes in the same carriers.8 One may reasonably assume that most such deaths are due to potentially correctable VF.1 2 In the past, it has been standard practice for cardiac arrest on board to be managed by prompt diversion to a nearby major airport for definitive treatment.8 Diversion from cruise altitude, however, cannot be accomplished in <20 minutes except under highly unusual circumstances. Because survival is minuscule after 16 minutes, even with effective CPR, this policy cannot reasonably be defended as a logical approach.10 A more logical and practicable approach is to place an AED on board the aircraft and train the cabin crew to assist in its use and in CPR.11 The use of such devices by EMTs outside the hospital has resulted in survival rates from VF comparable with those achieved by paramedics delivering all components of ALS.12 13 Experience with AEDs has prompted recent interest in PAD,14 of which aircraft use is a specific example. We describe such a system as it has operated on the Australian airline Qantas since 1991. Results to date are comparable with those of conventional emergency prehospital services, whereas experience gained appears to have lessened diversions in futile situations and improved operational performance. The system operates in conformity with guidelines set by AHA for PAD.14
In 1991, AEDs (Laerdal Heartstart 3000) were installed in the major international Australian terminals and into each of the 55 international Boeing 747 and 767 fleet. All such aircraft were so equipped by August 1992, and all 380 FSDs (equivalent to chief pursers) were trained to operate the device and supervise the management of cardiac arrest. All cabin crew (≈4000) were trained in the expeditious extrication of unconscious passengers from their seats and in CPR. Handling of cardiac arrest was incorporated into regular scheduled retraining programs, and defibrillator testing was incorporated into routine maintenance. Flight crew received instruction in the program, and facilities were upgraded for improved communication between personnel on board and Qantas medical staff in Sydney.
Steps involved in the emergency procedure are as follows: (1) problem noted by fellow passenger; cabin crew member alerted; (2) crew member approaches and notes problem; FSD is notified; (3) FSD collects AED and medical kit and proceeds to patient; (4) crew members arrange extrication to door bay and commence CPR; (5) call is made for physician on public address, and the pilot is advised; (6) FSD directs resuscitation and opens AED; (7) clothes are cut off patient with scissors, and pads are applied; (8) rhythm interrogation occurs; if VF, AED is charged and shock is delivered; (9) defibrillation is repeated with CPR according to AHA guidelines15 ; intravenously administered drugs (epinephrine, bicarbonate, lidocaine) are available, as is equipment for endotracheal intubation, suction, and ventilation with 100% oxygen; (10) physician volunteer, if available, is informed of protocol and facilities; (11) pilot is advised of progress and of FSD and physician opinion; (12) pilot considers advice and options for diversion; and (13) pilot contacts Qantas medical in Sydney and discusses options.
The Qantas medical kit is extensive8 and contains all equipment for ALS15 if a medical practitioner volunteers and wishes to use them. Qantas staff training is limited to use of face mask, Guedel’s airway, pharyngeal suction, and operation of the AED. The procedure is intended to be initiated so expeditiously that rhythm interrogation and first shocks (if required) have been delivered before a medical volunteer is identified. The aim in training and in practice is to have steps 2 through 8 carried out within 6 minutes and steps 6 through 8 within 1 minute. This has been achieved, as indicated in Fig 1⇓.
Qantas medical staff in Sydney are available on a 24-hour basis to discuss medical problems with the FSD or medical volunteers through the flight crew. Communication improvements will soon enable the FSD or medical volunteer as well as the flight crew to speak directly with Sydney medical staff. On rare occasions, Qantas medical staff seek further cardiological advice in Sydney. Medical discussions never involve the initial procedures (to step 8) but are usually concerned with discontinuation of resuscitation or options for diversion. Such advice is also available for other medical problems.
In Sydney and Melbourne terminals, the Qantas registered nurse is responsible for the dedicated AED. In other terminals, rapid defibrillation depends on availability of an on-board AED.
Reports are prepared by the FSD on all medical emergencies in aircraft. Medical volunteers are invited to add to this report. The Heartstart summary is printed from the machine on return to Sydney. All documents are collated and scrutinized by supervisors of the program (E.D. and M.O.). In preparation of this report, a pioneer of prehospital care (J.S.G.),16 formerly of Belfast, agreed to audit all original documents and assist in its preparation.
Over the 65-month study period, Qantas flew 203 191 flight sectors (take-offs and landing) and carried ≈31 million passengers for 201 billion passenger miles in its 55 B747 and B767 international airliners. Passengers carried on Qantas over the period accounted for 1.6% of all IATA airlines. Over this period, there were 27 episodes of sudden death on aircraft and 19 in the major Australian international terminals, attended by Qantas staff. The AED was used in all of these episodes and with 63 other acutely ill persons (54 in aircraft and 9 in terminals) for monitoring purposes. Cardiac emergencies were by far the most common serious conditions encountered; most occurred in persons previously in apparent good health. Only 1 of the 27 patients who experienced cardiac arrest on the aircraft was known to be ill at check-in, and this individual was traveling with a medical escort. Of persons with cardiac arrest in aircraft whose age was known, the average age was 68 years, with the youngest being 29 years old.
Problems in Aircraft
There were 27 episodes of cardiac arrest that necessitated CPR and use of the AED with a view to possible defibrillation (Table 1⇓). On 16 occasions, loss of consciousness was witnessed. Eight passengers could not be roused from apparent sleep; of these, 7 were found to be in asystole. Six passengers (all with witnessed arrest) were in VF. This was successfully terminated in 5; 1 passenger remained in VF despite the application of eight shocks. In all 6 passengers with VF, the aircraft was diverted, expedited to its destination, or (if on the ground) promptly brought to the terminal, with early alert of ground personnel and request for paramedic takeover on arrival. Two of the 6 were long-term survivors (≥2 years), with no residual cerebral defect. Another might have survived but the ambulance takeover was ineffective.
Case reports of the 2 survivors have been published.11 The first, a 67-year-old male Texan tourist, developed VF over the north Pacific Ocean at 1000 miles from Los Angeles on a direct flight to Sydney. Three shocks were required before stable sinus rhythm was restored (Fig 1⇑); the first was delivered 35 seconds after the AED was opened. The aircraft was diverted to Honolulu, where the passenger was fully conscious on arrival. The second survivor, a 79-year-old woman, experienced VF over Germany on a flight from Singapore to London. She reverted with a single shock delivered 58 seconds after the AED was opened, and the aircraft was expedited into London.
Other rhythms in cardiac arrest were asystole (11 passengers) and pulseless IVR (10 passengers) (Table 1⇑). No shock was recommended or delivered in any of these cases. All patients with asystole or IVR died. All with asystole were declared as deceased, usually after a prolonged resuscitation attempt and following advice from an identified medical practitioner on board and/or from Qantas medical staff in Sydney. No aircraft was diverted for asystole. Before 1995, aircraft were diverted because of 3 cases of cardiac arrest due to IVR, but none of the 3 passengers survived.
The AED was used by the FSD in cases of sudden collapse or was requested by volunteer medical officers for 54 passengers with acute medical problems but without prolonged cardiac arrest (Table 2⇓). ECG monitoring was not the intended use of the device, and attending physicians were advised that accurate ECG complex interpretation (eg, ST-segment assessment) was not possible with the device. They also were advised to monitor only for short periods in case defibrillation was required later. The availability of rhythm monitoring enhanced medical care and improved information on which a decision of whether to divert was made. Diversions or expedited landings were undertaken on 12 occasions for monitored passengers, usually when there was clinical evidence of continuing myocardial ischemia, acute infarction, or stroke that could not be treated effectively on board. The rhythm shown on the monitor was not the sole reason for diversion in any case.
Two of the passengers are known to have died subsequently in hospital. In addition, the monitored passengers included 2 with apparent cardiac arrest, in whom resuscitative measures were initiated but sinus rhythm was detected and maintained, and who subsequently regained consciousness. Although the clinical presentation was one of cardiac arrest, these persons were not so categorized.
Problems in Terminals
Nineteen episodes of cardiac arrest occurred in terminals (Fig 2⇓). All were witnessed, in contrast to just 16 witnessed arrests of the 27 (59%) occurring on aircraft. In contrast, too, 17 persons (89%) were found to be in VF, with 1 each in asystole and IVR. Defibrillation was initially successful in 16 with VF; 4 of the 17 (24%) were long-term survivors. Of the 19 persons with cardiac arrest in the terminals, all except 1, an airline employee, appeared to be passengers arriving or departing.
The AED was requested and used for monitoring 8 passengers in the terminal and 1 staff member (Table 2⇑).
Results presented here challenge the approach taken by most IATA carriers, including the major US airlines, to cardiac arrest in aircraft. Standard protocols, defended vigorously by the airline industry,8 recommend diversion to the nearest appropriate airport. This is unlikely to happen within 20 minutes and is impossible within the 16-minute time window that is relevant to the management of VF. Even if an aircraft is taxiing in line for takeoff, it can take 10 to 15 minutes to return to its bay after permission has been sought from and given by controllers. This issue was tackled in John Crewdson’s outstanding investigative report in the Chicago Tribune.8 The Qantas experience, although small, supports the concept of PAD as endorsed by the AHA,14 the arguments presented by Crewdson8 and Gray’s JAMA editorial assertion that, “The only opportunity to save a prehospital arrest victim is at the scene.”10
Initiation of the Qantas cardiac arrest program resulted from a combination of circumstance, good luck, and experience with defibrillation in other situations. Qantas is the major international carrier of a country that is further removed than any other from its neighbors and major trading partners. Flight sectors are unusually long, and in the past, multiple refueling stops were necessary on major routes. The traveling public came to expect the airline to offer succor, safety, and sustenance as well as transport. An important step toward initiation of this program was the successful introduction of AEDs into all 740 standard ambulances in the state of New South Wales. When results of this EMT system were found to be similar to those of paramedics,13 as in Seattle,12 there was pressure on Qantas management and board of directors to equip terminals and fleet. Laerdal, which had supplied the EMT ambulance fleet, provided assistance. The decision to equip with AEDs was made on medical grounds. There was no reason to believe that the decision might provide a commercial or operational advantage. Indeed, apart from obvious expense—purchase, carriage, training, and maintenance—there was concern that carriage of the devices might encourage diversion of aircraft and so incur extra cost to the company and inconvenience to passengers.
With respect to frequency of cardiac arrest, experience with the Qantas system is in line with the figures given in the Chicago Tribune8 and earlier U.S.A. Today reports.9 These sources estimated that sudden death from cardiac arrest occurred in as many as 1000 passengers annually in scheduled passenger aircraft. Extrapolations from our experience suggest comparable figures for the industry as a whole (Table 3⇓). These numbers are greater than deaths from aircraft accidents in IATA carriers.8 However, although the present risk to a passenger from trauma is lower than that from cardiac arrest, such risk has led to expensive safety facilities and cabin crew training, whereas cardiac arrest can be managed with far less expensive equipment and training. Certainly, the individual risk of either type of event is not high. In 5 years, only six of the Qantas on-board AEDs have been used to treat VF. As with other aircraft safety equipment, most AEDs will never be put to their intended use during their operational life.
Just 6 of the passengers with cardiac arrest in flight were found to be in VF; 11 were in asystole. Although other conditions (eg, pulmonary embolism, stroke) may have been responsible for cardiac arrest in these passengers, experience in the terminals (with 17 of 19 in VF after witnessed collapse [89%]), together with the fact that only 3 of those with asystole in flight were definitely seen to collapse, suggests that the majority were initially in VF, which degenerated into asystole.
The management of cardiac arrest was prompt and orderly. Cabin crew are trained to respond quickly to emergencies and to abide by set protocols. An indication of such response was the short time to defibrillation after the device was opened (Fig 1⇑). Of the five episodes of VF initially handled by crew, time to defibrillation was 27 to 58 seconds, for an average of 38 seconds. In the only instance in which a medical practitioner attended the patient from the start, the time to defibrillation was 2 minutes 58 seconds. Cabin crew were trained and retrained in the extrication and CPR procedures in a crowded simulated cabin area at meal time. The real event was observed by medical volunteers to run as well as under similar circumstances in an ambulance environment or hospital. When successful, passengers and crew were elated. When unsuccessful, crew often harbored feelings of guilt and frustration. Sensitivity is required on the part of those to whom crew must report on arrival, from crew supervisors and senior colleagues.
The incidence of cardiac arrest in airline terminals was surprisingly high but in line with recent data.17 The total number of passengers at risk was probably smaller than that in aircraft. All cardiac arrests in the terminal were witnessed, and 89% of persons (17 of 19) were in VF. The combination of arousal, anxiety, and unaccustomed exercise may have predisposed persons with subclinical coronary or cardiac disease to VF.18 19 Experience in the terminals encourages the view that airline companies wishing to initiate a similar program might best commence here, so they can deal with passengers who collapse in the terminals as well as those who arrive so stricken in aircraft. Both situations require a standing operational plan, together with good liaison with emergency ambulance and hospital resources.
The Laerdal AEDs functioned well. Shocks were delivered appropriately in all with VF and in none with sinus rhythm, IVR, or asystole. Newer AEDs are available from Laerdal and other companies that are lighter, less expensive, and easier to use and require less maintenance than the original Heartstart 3000 AEDs.
Before initiation of this program, Qantas followed the procedure of most US carriers and diverted in most cases of cardiac arrest when CPR was undertaken. This procedure was disruptive and expensive. After its initiation, no passenger survived asystole or IVR, and arrangements for resuscitation at the port of diversion for an unscheduled arrival out of hours were often primitive. Over the past 5 years, there have been no diversions for cardiac arrest caused by asystole, and over the past 2 years, there have been none for IVR. Actions are based on studies of outcome in prolonged resuscitation.10 15 20 21 22 The availability of the AED appears not only to have enhanced management of cardiac arrest but also to have avoided unnecessary and futile diversions.20 21 No detailed cost estimates have been made, but improved operational performance may actually have recovered the cost of the defibrillator program (Table 3⇑). This is just one issue that can be tackled prospectively by airlines (including the major US carrier American)23 that intend to initiate similar programs.
Selected Abbreviations and Acronyms
|AED||=||semiautomatic external monitor-defibrillator|
|AHA||=||American Heart Association|
|ALS||=||advanced life support|
|EMT||=||emergency medical technician|
|FSD||=||flight service director|
|IATA||=||International Airline Transport Association|
|PAD||=||public access defibrillation|
Dr Geddes was supported by a grant from St Vincent’s Clinic Foundation (Carroll Bequest). We would like to thank our Qantas medical colleagues, nursing staff, FSDs, and cabin staff who by their enthusiastic support made this program possible.
- Received April 22, 1997.
- Revision received June 30, 1997.
- Accepted July 3, 1997.
- Copyright © 1997 by American Heart Association
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