Medical monitoring comes to the cabin

 - May 7, 2008, 11:05 AM

For around $10,000 per year, aircraft operators can now fly with diagnostic equipment that will allow them to relay vital medical data to ground-based emergency support physicians. The application of the equipment on air- craft is too new yet to have generated firm evidence on the extent to which it can save lives, but early indications are that in many cases it will make an important contribution to the effectiveness of in-flight treatment. It also promises to help aircrews make critical decisions as to whether or not it is necessary to make costly diversions.

But the performance and specifications of the available diagnostic equipment vary significantly, posing the classic consumer dilemma: “just how good a mousetrap do I need?” The three products currently available essentially offer users the sort of functionality that ground-based physicians would feel most comfortable with and solutions that have made a higher priority of pragmatism and cost efficiency.

The equipment also poses important questions about the degree of crew training and responsibility required by operators. And some medical professionals have also warned against focusing on diagnostic procedures at the expense of essential first aid in critical situations.

“There needs to be more emphasis on immediate patient assessment than diagnosis,” said Gary Buchanan, director of training with UK-based emergency medical-support specialists The First Call in a September 27 presentation to Britain’s Business Aircraft Users Association (BAUA). Buchanan, who is a veteran paramedic and resuscitation specialist, emphasized to corporate crews what can be done in the so-called “platinum 10 minutes” after the start of a medical emergency. He noted that 20- to 40 percent of “pre-hospital” deaths are preventable. Conventional wisdom talks of the “golden hour” limit to get critically ill or injured patients to a hospital, but this can clearly be more challenging when airborne than on the ground–at least as far as fixed-wing aircraft are concerned.

According to Dr. Graham Creswell, medical director of BMI British Midland Airways, there is no danger of diagnostic equipment becoming a distraction to first aid so long as the operator’s training protocol makes it clear that when a passenger is unconscious or apparently not breathing the priority is to use the defibrillator. Earlier this year, BMI became the launch operator of the Tempus 2000 system developed by UK-based Remote Diagnostic Technologies (RDT). Creswell, who is also a line pilot with BMI, added that it is too soon to judge the effectiveness of the equipment, but he concluded that the incidence of numerous in-flight incidents to date suggests that it will “help a lot.”

To underline the importance of immediate care, The First Call’s Buchanan ran through the most common medical emergencies according to patient age range. For instance, he stated, the most common age range for heart attacks is 55- to 65-year-olds. Half of all heart-attack victims die within the first two hours of the attack, and 90 percent of these people within the first 10 min. “In this situation, the most important need is for oxygen within 20 to 30 minutes to prevent brain death,” explained Buchanan. “Oxygen supply is vital, and so is good airway management.”

In Buchanan’s view the single most important piece of medical equipment to have in an aircraft is a defibrillator since this is “the only thing proven to reverse a cardiac arrest.” Importantly, diagnostic equipment can be simultaneously used alongside a defibrillator only if it has been certified by aviation and health officials not to cause electrical interference.

The Big Debate

It could be argued that there is at least as much rationale for installing in-flight diagnostic systems in corporate aircraft because statistically there is less likely to be a doctor on board than on a widebody airliner. Similarly, at face value, the apparent post-middle-age, hard-living passenger profile of business jet operations seems likely to include a higher proportion of prospective heart-attack victims. What’s more, the cost of a needless diversion due to mistaking heartburn for a heart attack could potentially run into millions if a top executive misses a make-or-break meeting.

New in-flight diagnostic system supplier EMS-Link has breached the consensus in the debate over diagnostic equipment and expertise requirements by arguing that rival systems are too complex and costly for most aircraft operators. According to the West Bend, Ind.-based company’s CEO, Paul Egan, the EMS-Link system is so intuitive that it can be used by aircrew without any prior training whatsoever. In fact, he went so far as to argue that training is an expensive waste of time since for such an infrequently practiced procedure, the vital information would soon be lost.

However, the EMS-Link system itself was due to start flight trials in a Cessna Citation only late last month. This will be the first time that the complete system has been fully evaluated for its reliability of air-to-ground data transmission and use by an untrained aircrew.

EMS-Link told AIN that the Compaq laptop computer and the Zoll defibrillator that are used in its system have been separately approved by U.S. authorities after use by the U.S. Air Force. According to Egan, the EMS-Link help screen tells users when they are correctly administering CPR. In fact, the Compaq laptop is being used as a temporary platform and the company intends to replace it with a new Microsoft tablet computer before year-end.

According to Egan, EMS-Link users need do no more than connect the system to the aircraft satcom. Once connected, the support team at the University of Texas Medical Branch in Galveston directly controls all operations, instructing the crew how to attach monitors to the patient.

Training Issues

But competing diagnostic system suppliers RDT and TeleMedic Systems have both argued that some initial training is essential. In the case of RDT’s Tempus 2000 system, this takes no more than four hours for up to half-a-dozen crewmembers. To date, more than 250 crewmembers have been trained on Tempus, including those of its second airline customer Virgin Atlantic. “I would not want to be using a medical device for the first time during an emergency,” said RDT’s Kate Murphy.

TeleMedic claims its VitalLink 1200 system needs just one hour of initial training, supported by an instructional CD-ROM. Neither RDT nor TeleMedic requires recurrent training for its system, although medical-support services such as MedAire recommend it.

Acknowledging that cognitive recall of training can quickly deteriorate, Murphy said the Tempus help screens are designed to guide crew through the procedures. In any case, the equipment has dual controls so that the ground-based medic can take over immediately in the event a crewmember becomes overwhelmed.

The EMS-Link kit is being marketed on five-year full-service leases for $9,980 per annum, including medical support from the University of Texas. It uses a five-lead electrocardiogram (ECG) and also measures blood pressure, heart rate, air volume in lungs and oxygen concentration.

Unlike RDT and TeleMedic Systems, EMS-Link requires that medical support is provided by its chosen supplier. Although the other two have links with leading providers such as MedAire, they do permit customers to choose their own.

At a base purchase price of $19,995, VitalLink uses a three-lead ECG and also takes blood pressure, pulse oximetry and temperature readings. Voice and data output goes to on-ground support teams via a single telephone line, with the voice being recorded and digitized for transmission separately from–and not simultaneously with–the data.

By contrast, RDT’s Tempus requires two separate lines, one for data and video pictures and the other for voice. According to TeleMedic chief executive Chris Turner, that VitalLink had been developed with remote ground locations in mind where two satellite telephone lines are unlikely to be available. He argued that two lines would not always be available in corporate aircraft and even in airliners.

TeleMedic intends to add video output by year-end. Connections can also be made via the Internet, which research and development v-p Matthew Burke believes can be more reliable, especially for sending video pictures. The system has its own error-checking and correction protocol to guard against transmission problems caused by factors such as sun spots.

Burke said VitalLink works “fine” at the current narrowband satcom connection rates of 2.4 kbps, but added that as 64-kbps broadband service becomes more commonplace data transfer rates will definitely improve. RDT agreed that broadband links would improve the diagnostic systems’ performance (especially for byte-hungry video), but does not anticipate many corporate aircraft operators opting for them in the short term.

BMI’s Creswell told AIN that the only problem it had encountered with Tempus 2000 to date had been due to satcom connection reliability. It subsequently transpired that the airline’s crewmembers had not appreciated that the equipment might need several attempts to connect successfully and Creswell conceded that the carrier’s expectations had not been realistic. RDT has since reprogrammed the Tempus monitors to give more accurate connection status reports.

TeleMedic recommends that customers keep VitalLink’s patient display unit (PDU) six feet from the patient, on the grounds that in the event of a seizure he or she could lash out and break the equipment. Wireless links between the PDU, the medical unit and the aircraft communications system allow the display to be positioned separately (up to 300 ft away). A headset and microphone are provided with the PDU to ensure that operators can clearly hear the voice link even when the display is positioned away from the patient. RDT, with a PDU attached by cord to the Tempus 2000 base unit, has taken the view that this six-foot separation can present operational restrictions and so has not made the recommendation.

VitalLink’s use of a wireless connection begs the question whether this could present certification issues for future airline clients needing to contend with restrictions on RF interference between electronic devices in the cabin and cockpit avionics. Turner told AIN that a decade ago this would have been more problematic but that today airliners are increasingly being equipped with entertainment and communications systems that can overcome this issue.

Twelve or Just Three?

RDT’s Tempus 2000 system, which sells for approximately $50,000, is the only available in-flight diagnostic equipment to use the more advanced 12-lead ECG. Both TeleMedic and EMS-Link have argued that the 12-lead system is surplus to requirements and too complex and time-consuming for non-medical personnel to
use.

However, RDT said it opted for the 12-lead system on the advice of the medical consultants with whom it works. “They insisted that only a 12-lead ECG is capable of full diagnosis,” explained Murphy. Furthermore, the Tempus 2000’s 12-lead ECG comes in the form of a harness that wraps around the patient’s chest without the need to attach individual monitors to skin.

Not all medical specialists have concluded that 12-lead ECGs are essential for in-flight diagnostic applications. According to Prof. Douglas Chamberlain, a retired cardiology consultant who has advised both the UK Civil Aviation Authority and British Airways, the 12-lead ECG definitely provides much more data than a three-lead unit. But in his view the more sophisticated system may actually generate more information than can usefully and practically be applied during in-flight emergencies.

“In emergency situations, simplicity and speed are all important,” wrote Chamberlain in a published comment on the issue. “Even if there were marginal advantages in recording and transmitting with a 12-lead ECG as opposed to a three-lead ECG (and I do not think there are) such minor considerations would be outweighed by the greater sense of ease of a three-lead recording.”

But the RDT team does not accept that it has sacrificed simplicity and speed of operation to offer more comprehensive medical data. Its 12-lead ECG features a rubber harness that fits over the patient’s chest, positioning sensors as close as possible to the optimum locations for vital-sign recording. According to RDT, the flexible rubber harness can extend to fit all but very small children and extremely obese people, and the system is said to be usable on patients beyond the 95th percentile of body dimensions.

Demonstrations have shown that the Tempus harness can be fitted below a patient’s clothing without the need to undress the patient. According to TeleMedic, VitalLink’s ECG leads need be fitted only to a patient’s fingers, wrists and ankles.

The Tempus 2000 transmits medical data, voice and video over satcom connections, using a separate line for voice transmissions to allow operators to speak to doctors and relay data and video in real time. According to RDT, its patented advanced data robustness (ADR) software overcomes transmission problems caused by noise and signal fade. “ADR fools the modems at each end into thinking that the connection has not been lost,” explained Murphy. “Any data that does not go through is stored until the transmission is restored.”

In addition to the ECG, the Tempus equipment monitors pulse rate, blood-oxygen levels, temperature, blood pressure and capnometry (breath gas analysis). It can perform multiple readings simultaneously but cannot transmit ECG and video at the same time.

Customers can have baseline medical data stored with the service, as well as a full history of pre-existing conditions. Their personal physicians can participate in the consultation via a real-time Web link. All data and video images are automatically stored for future reference.

Tempus can also be used for offline monitoring. This might be useful if, for instance, an aircraft is flying above polar regions where no satcom connection can be made or if the doctor wants the patient to be monitored for a prolonged period.

The system’s battery provides power for up to four hours of continuous use and can be recharged while the aircraft is on the ground. Once in sleep mode the battery will last up to 12 months without recharging, losing just one hour’s output after six months of inactivity. TeleMedic Systems has just upgraded the VitalLink battery for nine hours of continuous use, falling to four hours after six months of inactivity.

Executive charter and management operator PrivatAir is now installing Tempus 2000 on its three Boeing Business Jets. The system has also been supplied to several Middle East head-of-state transports, and Jet Aviation has agreed to market the equipment through its completion and refurbishment centers. In June, two U.S. aircraft owners have had the VitalLink system fitted to a Challenger 604 and Citation X.