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The role of the aeromedical helicopter
The Role of the Aeromedical Helicopter by James R. Mackenzie, M.D.
The logical progression of emergency medical care transportation from BLS to ALS and from ALS to ALS fortified by a physician is to develop a hospital-based helicopter service. (PhotocourtesyMBB HelicopterCorporation)
The helicopter has added a new dimension to emergency medical care. Since its inception as a patient transporter, the role of the helicopter has evolved from a speedy and agile swoop and scoop BLS system into a very specialized life support system (VSLS). This system is rapidly becoming an extension of the services provided by the most sophisticated emergency department in the region.
Hospitals and Ambulances Hospitals were organized to provide space, equipment, personnel and back-up facilities for more sophisticated care than could be given in the doctor's office or in the clinic. The emergency department was developed to extend the sophisticated care of the hospital to the emergency patient in the surrounding community,. The ambulance was developed to extend the sophisticated emergency care given by the hospital and its emergency department to the boundaries of a large enough community to make that hospital economically viable. The development of hospital-based
ambulance systems became the cost-effective alternative to building a hospital on every other block. The level of care that a hospital can cost effectively give is in direct proportion to the population it
serves. The community or primary hospital serves communities in multiples of 6,000 people - the number necessary to clinically support three general practitioners (ie 2,000 per physican). Doctors usually work in threes, because working in pairs put an excess burden on the one remaining when the other one is away. The secondary hospital serves communities in multiples of 40,000 the number necessary to clinically support three internists or three surgeons (ie. 13,000 per specialist). The tertiary hospital serves communities in multiples of 500,000 - the number necessary to support three neurosurgeons, three cardiovascular surgeons or three neonatal cardiologists, and to support their clinical research efforts if they are part of an academic institution (ie. 150,000 per specialist). ALS and BLS Response Time The role of the ambulance service is to extend the level of emergency medical care provided by the hospital to the boundaries of the community which it serves - be it local, regional or area wide. The basic life support (BLS) ambulance is
The hospital-based helicopter can reach its full potential if based at, or closely aligned with a tertiary level hospital HOSPITAL AVIATION, JULY 1984
25
the hour, include tension pneumothorax, tamponade, massive hemorrhage, persistent recurrent ventricular fibrillation, or complicated airway problems which need crycothyroidotomy or tracheotomy because of the inability to pass an endotracheal tube. The ALS ambulance carries out its role in one of two ways. It acts as a backup for the BLS ambulance transporting those patients with complicated illnesses or injuries; and secondly, it becomes a transferring agent for patients from a primary or secondary level hospital needing care from a hospital one level higher.
One properly staffed and equipped aeromedical helicopter can provide the same "'golden hour" response time it would take dozens of ground vehicles to equal, at a fraction of the cost. (Photo courtesy Jewish Hospital Skycare)
a primary responder providing advanced first aid especially for people who need airway or ventilatory support. It serves the primary or community hospital to the boundaries of its 6,000 population. Its maximum response time to be effective in preventing death from airway complications is 15 minutes. The role of an advanced life support (ALS) ambulance is as a secondary responder which provides airway and ventilatory support for patients with more complicated respiratory problems as well as sophisticated circulatory support for patients with failing hearts due to hypovolemia or to 26
HOSPITAL AVIATION, JULY 1984
myocardial failure. The job of the ALS ambulance is to serve the secondary hospital to the boundaries of its 40,000 population. The maximum response time for an ALS ambulance to be effective is 15 minutes beyond the effectiveness of the BLS ambulance (30 minutes). The reason for the time limitation is that deaths which can only be prevented by the ALS system occur within the first hour, Therefore, the ambulance can only go out 30 minutes and come back 30 minutes if it is to be effective for those groups of patients that benefit from definitive hospital care. Examples of this type of preventable death, the kind that actually need hospital care within
The Tertiary Transport The role of both BLS and ALS ambulances can be expanded to a tertiary care ambulance with very specialized life support services. This situation occurs w h e n a patient is transported to a tertiary level hospital from a lower level hospital. In such a situation, the ambulance crew is usually "fortified" by the presence of a nurse or a physician together with the specialized equipment (eg. ventilator). An example of this type of transfer includes patients with massive trauma who continue to bleed. These people need more than the technical and judgemental skills of an EMT or paramedic. They need nurse or physician care using ventilators and massive transfusions during the transportation to the definitive care hospital. Other types of patients who need the VSLS are those that may need pericardiosenthesis or even thoracotomy during transport. Other examples include the use of BLS or ALS ambulance for neonatal transfers or for high risk pregnancies who are about to deliver. The disadvantage, of course, of using a BLS or ALS ambulance is that it strips the communities where they originated of medical resources during transport (the ambulance, physicians and nurses). Enter the Helicopter The logical progression of emergency medical care transportation from BLS to ALS and from ALS to ALS fortified by a nurse or physician is to develop a hospital-based helicopter service which can give more sophisticated emergency medical care at the time of initial pickup and during
transport (ie. VSLS). In order to give VSLS care, the helicopter must be staffed by nurses and physicians who can respond immediately to the request for aid. It must therefore be based at a tertiary hospital which is capable of providing the most advanced level of care in the region or at least it must be closely associated with one of those types of hospitals. The role of the helicopter service then becomes clear. Its first and most important role is to be the tertiary responder providing very specialized life support care (VSLS) for patients with very complicated illnesses or injuries. The second most important role of the helicopter service is to act as an ALS ambulance system over a wider area where ALS systems are unavailable. It is important to realize that the presence of a doctor and nurse on board the helicopter means that hospital-type emergency care can be given at the scene, at the transferring hospital, or during flight. Therefore, the radius of operation of the flying ALS services (as opposed to the ground ALS service) is 60 minutes versus the 30 minutes alluded to previously. This translates into an equivalent of a 150-mile radius for the Twin Star which we are flying versus the 23 mile radius for our typical ALS ground ambulance which translated into 71,000 square miles from the epicenter versus 1,600 square miles from the epicenter of the ground ambulance service. This means that it would take 44 ALS ground ambulances to cover the same area as one helicopter. The third most important medical role for the helicopter is to conserve the emergency medical care resources of the community. If the community is too small to support an ALS system, then the helicopter can actually replace 44 of the ALS ambulances. The average cost of operating an ALS ambulance in Michigan is $200,000 per year for a total of $8.8 million per year for 44 ground ambulances. The annual operating cost for the University of Michigan helicopter service is $1.2 million by comparison. The last, but a very major role for helicopters is to use them as research tools to evaluate the need for different levels of care, and to develop clinical trials that need to be instituted early in the emergency to
affect care. For example, we are now considering clinical trials in which emergency coronary reperfusion protocols will be used early in patients with myocardial infarct; or using the aircraft to take extracorporeal membrane oxygenators to the scene for babies whose lungs are too immature to oxygenate the blood system.
Summary and Conclusions First the speed of the helicopter makes it the most cost-efective method for providing back up support for ALS services over sparsely populated areas. Secondly, the hospital-based helicopter service can only reach its full VSLS potential if it is based at, or closely aligned with the hospital giving the most sophisticated tertiary of care in the area it serves. The type of care demands the presence of nurses and physicians during flight. Thirdly, a corollary to the development of hospital-based helicopter services is
thatAt becomes the single most important tool for categorizing ability of hospitals to provide sophisticated emergency medical care. It will become the vertical categorying tool in the last part of this decade, and will do what all other attempts at hospital categorization have failed to do. Fourthly, the jury is still out on whether or not these helicopter services have made a positive impact on patient survival or indeed in decreasing the amount of permanent injuries. Certainly the Hanover study, the study completed by Dr. Bill Baxt of San Diego, and the initial analysis of the University of Michigan service, would suggest that they do. Dr. Mackenzie is Head of the Section of Emergency Services at the University of Michigan. Survival Flight is one of the Emergency Services programs. This article was originally presented at the 1983 ASHBEAMS/NFNA Conference ir, Denver.
The level o f care that a hospital can cost effectively give is in direct proportion to the p o p u l a t i o n it serves. HOSPITAL AVIATION, JULY 1984
27
The logical progression of emergency medical care transportation from BLS to ALS and from ALS to ALS fortified by a physician is to develop a hospital-based helicopter service. (PhotocourtesyMBB HelicopterCorporation)
The helicopter has added a new dimension to emergency medical care. Since its inception as a patient transporter, the role of the helicopter has evolved from a speedy and agile swoop and scoop BLS system into a very specialized life support system (VSLS). This system is rapidly becoming an extension of the services provided by the most sophisticated emergency department in the region.
Hospitals and Ambulances Hospitals were organized to provide space, equipment, personnel and back-up facilities for more sophisticated care than could be given in the doctor's office or in the clinic. The emergency department was developed to extend the sophisticated care of the hospital to the emergency patient in the surrounding community,. The ambulance was developed to extend the sophisticated emergency care given by the hospital and its emergency department to the boundaries of a large enough community to make that hospital economically viable. The development of hospital-based
ambulance systems became the cost-effective alternative to building a hospital on every other block. The level of care that a hospital can cost effectively give is in direct proportion to the population it
serves. The community or primary hospital serves communities in multiples of 6,000 people - the number necessary to clinically support three general practitioners (ie 2,000 per physican). Doctors usually work in threes, because working in pairs put an excess burden on the one remaining when the other one is away. The secondary hospital serves communities in multiples of 40,000 the number necessary to clinically support three internists or three surgeons (ie. 13,000 per specialist). The tertiary hospital serves communities in multiples of 500,000 - the number necessary to support three neurosurgeons, three cardiovascular surgeons or three neonatal cardiologists, and to support their clinical research efforts if they are part of an academic institution (ie. 150,000 per specialist). ALS and BLS Response Time The role of the ambulance service is to extend the level of emergency medical care provided by the hospital to the boundaries of the community which it serves - be it local, regional or area wide. The basic life support (BLS) ambulance is
The hospital-based helicopter can reach its full potential if based at, or closely aligned with a tertiary level hospital HOSPITAL AVIATION, JULY 1984
25
the hour, include tension pneumothorax, tamponade, massive hemorrhage, persistent recurrent ventricular fibrillation, or complicated airway problems which need crycothyroidotomy or tracheotomy because of the inability to pass an endotracheal tube. The ALS ambulance carries out its role in one of two ways. It acts as a backup for the BLS ambulance transporting those patients with complicated illnesses or injuries; and secondly, it becomes a transferring agent for patients from a primary or secondary level hospital needing care from a hospital one level higher.
One properly staffed and equipped aeromedical helicopter can provide the same "'golden hour" response time it would take dozens of ground vehicles to equal, at a fraction of the cost. (Photo courtesy Jewish Hospital Skycare)
a primary responder providing advanced first aid especially for people who need airway or ventilatory support. It serves the primary or community hospital to the boundaries of its 6,000 population. Its maximum response time to be effective in preventing death from airway complications is 15 minutes. The role of an advanced life support (ALS) ambulance is as a secondary responder which provides airway and ventilatory support for patients with more complicated respiratory problems as well as sophisticated circulatory support for patients with failing hearts due to hypovolemia or to 26
HOSPITAL AVIATION, JULY 1984
myocardial failure. The job of the ALS ambulance is to serve the secondary hospital to the boundaries of its 40,000 population. The maximum response time for an ALS ambulance to be effective is 15 minutes beyond the effectiveness of the BLS ambulance (30 minutes). The reason for the time limitation is that deaths which can only be prevented by the ALS system occur within the first hour, Therefore, the ambulance can only go out 30 minutes and come back 30 minutes if it is to be effective for those groups of patients that benefit from definitive hospital care. Examples of this type of preventable death, the kind that actually need hospital care within
The Tertiary Transport The role of both BLS and ALS ambulances can be expanded to a tertiary care ambulance with very specialized life support services. This situation occurs w h e n a patient is transported to a tertiary level hospital from a lower level hospital. In such a situation, the ambulance crew is usually "fortified" by the presence of a nurse or a physician together with the specialized equipment (eg. ventilator). An example of this type of transfer includes patients with massive trauma who continue to bleed. These people need more than the technical and judgemental skills of an EMT or paramedic. They need nurse or physician care using ventilators and massive transfusions during the transportation to the definitive care hospital. Other types of patients who need the VSLS are those that may need pericardiosenthesis or even thoracotomy during transport. Other examples include the use of BLS or ALS ambulance for neonatal transfers or for high risk pregnancies who are about to deliver. The disadvantage, of course, of using a BLS or ALS ambulance is that it strips the communities where they originated of medical resources during transport (the ambulance, physicians and nurses). Enter the Helicopter The logical progression of emergency medical care transportation from BLS to ALS and from ALS to ALS fortified by a nurse or physician is to develop a hospital-based helicopter service which can give more sophisticated emergency medical care at the time of initial pickup and during
transport (ie. VSLS). In order to give VSLS care, the helicopter must be staffed by nurses and physicians who can respond immediately to the request for aid. It must therefore be based at a tertiary hospital which is capable of providing the most advanced level of care in the region or at least it must be closely associated with one of those types of hospitals. The role of the helicopter service then becomes clear. Its first and most important role is to be the tertiary responder providing very specialized life support care (VSLS) for patients with very complicated illnesses or injuries. The second most important role of the helicopter service is to act as an ALS ambulance system over a wider area where ALS systems are unavailable. It is important to realize that the presence of a doctor and nurse on board the helicopter means that hospital-type emergency care can be given at the scene, at the transferring hospital, or during flight. Therefore, the radius of operation of the flying ALS services (as opposed to the ground ALS service) is 60 minutes versus the 30 minutes alluded to previously. This translates into an equivalent of a 150-mile radius for the Twin Star which we are flying versus the 23 mile radius for our typical ALS ground ambulance which translated into 71,000 square miles from the epicenter versus 1,600 square miles from the epicenter of the ground ambulance service. This means that it would take 44 ALS ground ambulances to cover the same area as one helicopter. The third most important medical role for the helicopter is to conserve the emergency medical care resources of the community. If the community is too small to support an ALS system, then the helicopter can actually replace 44 of the ALS ambulances. The average cost of operating an ALS ambulance in Michigan is $200,000 per year for a total of $8.8 million per year for 44 ground ambulances. The annual operating cost for the University of Michigan helicopter service is $1.2 million by comparison. The last, but a very major role for helicopters is to use them as research tools to evaluate the need for different levels of care, and to develop clinical trials that need to be instituted early in the emergency to
affect care. For example, we are now considering clinical trials in which emergency coronary reperfusion protocols will be used early in patients with myocardial infarct; or using the aircraft to take extracorporeal membrane oxygenators to the scene for babies whose lungs are too immature to oxygenate the blood system.
Summary and Conclusions First the speed of the helicopter makes it the most cost-efective method for providing back up support for ALS services over sparsely populated areas. Secondly, the hospital-based helicopter service can only reach its full VSLS potential if it is based at, or closely aligned with the hospital giving the most sophisticated tertiary of care in the area it serves. The type of care demands the presence of nurses and physicians during flight. Thirdly, a corollary to the development of hospital-based helicopter services is
thatAt becomes the single most important tool for categorizing ability of hospitals to provide sophisticated emergency medical care. It will become the vertical categorying tool in the last part of this decade, and will do what all other attempts at hospital categorization have failed to do. Fourthly, the jury is still out on whether or not these helicopter services have made a positive impact on patient survival or indeed in decreasing the amount of permanent injuries. Certainly the Hanover study, the study completed by Dr. Bill Baxt of San Diego, and the initial analysis of the University of Michigan service, would suggest that they do. Dr. Mackenzie is Head of the Section of Emergency Services at the University of Michigan. Survival Flight is one of the Emergency Services programs. This article was originally presented at the 1983 ASHBEAMS/NFNA Conference ir, Denver.
The level o f care that a hospital can cost effectively give is in direct proportion to the p o p u l a t i o n it serves. HOSPITAL AVIATION, JULY 1984
27