- Email: [email protected]
B-3 A review of interhospital critical care transport procedures in patients with acute myocardial infarction
B-I V A L I D T R A U M A H E L I C O P T E R T R A N S P O R T FOR P A T I E N T S W I T H ISS SCORES LESS T H A N 16 Eileen Pozzi, RN, CEN; Michael Rhodes, MD, FACS; M E D E V A C , Lehigh Valley Hospital Center, Allentown, Pennsylvania. INTRODUCTION: As a condition for approval of a hospitalbased helicopter program, a T r a u m a Review Committee composed of physicians, nurses, a d m i n i s t r a t o r s and prehospital personnel from 20 hospitals in 10 counties was organized to review all on-scene flights. The validity of each call for helicopter t r a n s p o r t to a t r a u m a center (TC) was determined. E a c h call was categorized as follows: 1. Valid -- Need for TC indicated a t the scene, consistent with findings at the TC. 2. Valid false-positive -- Need for TC indicated at the scene, b u t NOT consistent with findings at TC. 3. Non-valid -- Need for TC NOT indicated a t the scene, consistent with findings at TC. METHODS: The criteria used by the committee to determine validity included b o t h subjective a n d objective findings: Unresponsiveness to verbal stimuli B P -<.<90 P < 6 0 or >1120 RR~< 10 or >/30 Mechanism of injury (displacement of steering wheel, associated fatality, fall greater t h a n 20 ft.) E n t r a p m e n t greater t h a n 20 minutes. Scene history (time factors, weather, road conditions, age of patient). RESULTS: No. Pts. % ISS I Valid* 262 82.1% 27.85 II Valid false-positive 37 11.6% 7.92 III Non-valid 20 6.3% 8.65 319 * also included in this group were valid trauma/non-valid means of transportation (n = 10). ISS < 16 >/16 Total
Valid 63 199 262
Vfpos 34 3 37
Nonvalid 19 1 20
B-2 D E V E L O P M E N T OF A H O S P I T A L CONSORTIUM: A V O I D I N G T H E H A Z A R D S O F C O M P E T I T I O N I N AEROMEDICAL HELICOPTER TRANSPORT Timothy C. Fabian, Pamela Castleman, C. Richardson Patterson, Memphis Medical Center Air Ambulance Service, Inc., Memphis Tennessee. INTRODUCTION: Multiple medical helicopter services have been established in several localities as m a r k e t i n g tools, for the
SEPTEMBER/OCTOBER1987
AM~
M E T H O D S : Two large full-service hospitals, one regional t r a u m a center a n d One pediatric hospital successfully negotiated the creation of a n independent, non-profit helicopter service consortium. The consortium operates two twin-engine helicopters, a n d each flight crew is composed of a pilot a n d two critical-care nurses. The nurses were originally drawn from the hospital staffs as a n interim measure, b u t are now being converted to consortium staff to further the cooperative concept. The service is available to all hospitals in the area, which has a population of two million. RESULTS: D u r i n g the first nine m o n t h s of operation, t h e r e were 662 t r a n s p o r t s ; 355 cardiac/medical, 237 trauma, a n d 70 pediatric. The average TISS was 18 for cardiac/medical a n d t r a u m a flights a n d the seven-day mortality was 9% a n d 14%, respectively. M o s t of the t r a u m a t r a n s p o r t s have been to t h e t r a u m a center, a n d the adult non-trauma p a t i e n t s have been evenly d i s t r i b u t e d between the two full-service hospitals. Fifteen flights have been to non-sponsoring hospitals. There were 105 missed flights, only 14 of which were due to the equipment b e i n g in use. There have been no accidents. CONCLUSION: We believe this experience d e m o n s t r a t e s t h a t expensive, life-saving resources can be rationally allocated even in t o d a y ' s competitive environment. Our c o m m u n i t y faced the prospect of two or three competing helicopter services w i t h the consequent w a s t e of resources and potential for tragedy. The b r e a d t h and d e p t h of resources of the consortium hospitals h a s created instead a healthy and s t r o n g organization which serves the area well. The risks in aeromedical evacuation can be minimized by i n s u l a t i n g the service from competitive pressure.
Total 116 203 319
CONCLUSIONS: 1) I n a multi-faceted review, a n independent E M S committee found t h a t 24% of t r a u m a cases with ISS scores below 16 were considered valid for t r a n s p o r t to a t r a u m a center. The index of concordance (kappa) between ISS a n d E M S review was .491, p < . 0 0 0 1 . 2 ) A t o t a l of 20 p a t i e n t s {6.3%) were considered inappropriately transported. 3 ) T h e decision to t r a n s p o r t dead-at-scene p a t i e n t s with CPR in progress remains problematic.
30
sake of " c o m p e t i t i o n . " These communities are over-served with superfluous equipment and personnel, a n d the resulting cost is greater t h a n necessary to satisfy the local or regional need. There is also the possibility t h a t under-utilized resources in a competitive e n v i r o n m e n t will generate a pressure for liberalized utilization criteria with a r e s u l t a n t greater cost/need ratio and, more ominously, a relaxation of the safety guidelines necessary in aerotransport. We believe t h a t the helicopter is a n inappro-' priate competitive tool, and t h a t competing institutions can successfully combine to create a common helicopter service which serves the c o m m u n i t y and the participating i n s t i t u t i o n s and averts the hazards of unalloyed competition.
B-3 A R E V I E W OF I N T E R H O S P I T A L C R I T I C A L CARE TRANSPORT PROCEDURES IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION S u s a n L. E l s b e r n d Smith, RN; Joe B. Hejlik, RN; Flight Nurses, Mayo One Helicopter; Larry F. Vukov, MD; Michael B. Farnell, MD; Mayo Medical Center, Saint M a r y s Hospital, Rochester, Minnesota. INTRODUCTION:Nationally, large percentages of p a t i e n t s diagnosed with acute myocardial infarction (AMI) enter rural hospitals a n d require t r a n s p o r t to tertiary care centers for further care. M a n y times these p a t i e n t s are t r a n s f e r r e d b y basic life s u p p o r t (BLS) ambulance services with no t r a i n i n g in critical care life s u p p o r t skills. To determine the n u m b e r a n d frequency of those skills required during transport, the following retrospective s t u d y was performed. M E T H O D S : I n 1986, 96 consecutive p a t i e n t s with the primary diagnosis of A M I were t r a n s f e r r e d from rural hospitals to a t e r t i a r y care center via rotor wing. The n u m b e r of p a t i e n t s requiring one or more critical care skill a n d the n u m b e r of skills performed per p a t i e n t were reviewed. Parenteral medication a d m i n i s t r a t i o n (bolus and drip) and advanced procedures n o t performed b y Minnesota BLS services were included.
RESULTS: Of t h e 96 A M I p a t i e n t s studied: Number of procedures/medications Number of patients affected Required per patient 0 5/(5%) 1-2 39/(41%) 3-4 27 / (28%) 5-6 18/(19%) 7-8 4/(4%) 9-10 3/(3%) Skills Maintained # of Pts. Endotracheal intubation 7 (7%) CVP line 3 (3%) Swan Ganz line 3 (3%) Transvenous pacer 5 (5%) Medications Total no. of IV boluses: 55 Total no. of IV infusions: 131 Total no. of sublingual medications: 9
Skills Performed Enroute Endotracheal intubation External pacing Defibrillation IV insertion IV fluid titration NG insertion
# of Pts. 4 (4%) 7 (7%) 4 (4%) 22 (23%) 40 (42%) 10 (10%)
CONCLUSION: 95% of all p a t i e n t s t r a n s p o r t e d required critical care skills d u r i n g transport, of which 54% required more t h a n three. I n fact, 12 p a t i e n t s (13%) required inflight endotracheal intubation, defibrillation, or external pacing, which were p r o b a b l y life-saving procedures. The i n t e r h o s p i t a l t r a n s p o r t of acute myocardial infarction p a t i e n t s unequivocally suggest m a n a g e m e n t by individuals trained and equipped to provide critical care intervention.
B-4 THE COST-EFFECTIVENESS AND APPROPRIATENESS O F A I R VS. L A N D T R A N S P O R T OF C R I T I C A L T R A U M A AND HEART PATIENTS AMONG HOSPITALS: MADISON, WISCONSIN Michael Bowman, J e r r y Rose, Trudy Karlson, William Perloff, University of Wisconsin Hospital and Clinics, Madison, Wisconsin. INTRODUCTION: The relative costs and effectiveness of inter-hospital critical t r a u m a and h e a r t p a t i e n t s t r a n s p o r t e d b y helicopter a n d b:¢ ground ambulance are not known. The purposes of the s t u d y are to identify a n d compare helicopter costeffectiveness to g r o u n d t r a n s p o r t s cost-effectiveness. M E T H O D S : For 12 m o n t h s inter-hospital t r a u m a a n d h e a r t t r a n s p o r t s b y helicopter a t a major teaching hospital collected b y trained nurse a b s t r a c t o r s are compared with land t r a n s p o r t s d u r i n g the same period and for the previous 36 months. Effectiveness measures are mortality outcomes, a n d changes in severity during transport; cost measures include total costs of t r a n s p o r t a n d costs of hospitalization. Severity measures for h e a r t are Bever, T I S S and the Ischemic H e a r t Disease index. For t r a u m a cases measures were the Bever, TISS, Multiple T r a u m a Severity Index, T r a u m a Score, Multiple I n j u r y Severity Score and Glascow Coma Scale. D a t a are analyzed in crosstabulations, b y least-squares regression and logistic regression. Appropriateness measures are clinical a s s e s s m e n t s of p a t i e n t m a n a g e m e n t b y a panel of four physicians, two external. The analysis was conducted as p a r t of a CON demonstration.
effective. Similar results were found for improvements in severity d u r i n g t r a n s p o r t b y helicopter. For h e a r t patients, there was no i m p r o v e m e n t in mortality and in change in severity b y air. Since t o t a l costs were higher t h a n for land, h e a r t cases were not cost-effective. This s t u d y did not address the impact of air t r a n s p o r t on the early and timely m a n a g e m e n t of cardiac p a t i e n t s whose condition is amenable to invasive therapy such as T-PA a n d angioplasty.
B-5 E V A L U A T I O N OF M I D A Z O L A M (VERSED} I N T H E T R E A T M E N T OF C O M B A T I V E P A T I E N T S I N A E R O M E D I C A L T R A N S P O R T : A P I L O T STUDY Steven Murphey, L y n n Eastes, Gene Viglietta, S a m a r i t a n Air Evac, Phoenix, Arizona. INTRODUCTION: The r e s t r a i n t of combative p a t i e n t s is essential to the safety of the crew a n d efficacy of care in the aeromedical environment. Physical r e s t r a i n t is often inadequate, impractical, or medically undesirable. There exists a need to s t u d y a n d identify a rapid-acting, i n t r a v e n o u s pharmacological r e s t r a i n t to use in these patients. M E T H O D S : A protocol was developed for the r e s t r a i n t and sedation of combative p a t i e n t s in aeromedical transport. In this pilot study, the effectiveness of the new benzodiazapine, Midazolain, was evaluated as a pharmacological restraint. After adm i n i s t r a t i o n of the medication per protocol, the flight nurses completed a questionnaire providing s t u d y data. RESULTS: D u r i n g the s t u d y period, 11 p a t i e n t s were treated with Midazolam. The majority of the sample (N=6) had CNS insults, the remainder (N=) had metabolic or psychiatric etiologies for their combativeness. The m e a n age of the sample was 29 {range 14-53). The suggested s t a r t i n g dose was 1-3 m g slow IV push. M e a n s t a r t i n g dose was 3 m g (range 1-5 rag). In 8 (72%) of the cases, this dose proved a d e q u a t e for sedation. Three p a t i e n t s (27%) required additional medication to achieve the desired sedative effect. One patient was not adequately sedated after receiving 5 mg. Seven 163%) of t h e p a t i e n t s had received prior sedation, m o s t commonly, Diazepam (median dose 20 mg, range 10-100 rag). Four p a t i e n t s (36%) were i n t u b a t e d prior to the a d m i n i s t r a t i o n of Midazolam. Two p a t i e n t s (18%} experienced measurable respiratory depression, one requiring i n t u b a t i o n and one requiring no ventilatory support. No other u n t o w a r d effects were noted. Blood pressures were not assessed immediately before a n d after the a d m i n i s t r a t i o n of t h e Midazolam; however, no sustained hypotensive episodes were noted in the t r a n s p o r t records. Flight nurses reported a 10-15 minute duration of effect in the majority of patients. I n long fixed-wing flights, repeat doses in 2-3 m g increments were sometimes necessary to maintain the desired level of sedation. Mean Total Dose Administered Time of Onset Sedative Effect
Range 7.75 m g 2.7 min
2.5-10 m g .75-10 min
CONCLUSIONS: Midazolam proved to be a safe a n d effective m e t h o d of pharmacological r e s t r a i n t in this pilot study. Midazolam's rapid onset, s h o r t duration of action, and minimal respiratory depressive effects makes this drug an excellent choice for sedating combative p a t i e n t s during aeromedical transport.
R E S U L T S A N D CONCLUSIONS: Over 85 percent of the helicopter t r a n s p o r t s were judged appropriate b y a conservative rule. For t r a u m a patients, helicopter t r a n s p o r t showed a 23 to 32 percent decrease in severity-adjusted mortality, compared to land (p< .05). Since the total costs of air p a t i e n t s were equal to land costs, this is evidence t h a t helicopter t r a n s p o r t is cost-
A~$
SEPTEMBER/OCTOBER1987
31
Valid 63 199 262
Vfpos 34 3 37
Nonvalid 19 1 20
B-2 D E V E L O P M E N T OF A H O S P I T A L CONSORTIUM: A V O I D I N G T H E H A Z A R D S O F C O M P E T I T I O N I N AEROMEDICAL HELICOPTER TRANSPORT Timothy C. Fabian, Pamela Castleman, C. Richardson Patterson, Memphis Medical Center Air Ambulance Service, Inc., Memphis Tennessee. INTRODUCTION: Multiple medical helicopter services have been established in several localities as m a r k e t i n g tools, for the
SEPTEMBER/OCTOBER1987
AM~
M E T H O D S : Two large full-service hospitals, one regional t r a u m a center a n d One pediatric hospital successfully negotiated the creation of a n independent, non-profit helicopter service consortium. The consortium operates two twin-engine helicopters, a n d each flight crew is composed of a pilot a n d two critical-care nurses. The nurses were originally drawn from the hospital staffs as a n interim measure, b u t are now being converted to consortium staff to further the cooperative concept. The service is available to all hospitals in the area, which has a population of two million. RESULTS: D u r i n g the first nine m o n t h s of operation, t h e r e were 662 t r a n s p o r t s ; 355 cardiac/medical, 237 trauma, a n d 70 pediatric. The average TISS was 18 for cardiac/medical a n d t r a u m a flights a n d the seven-day mortality was 9% a n d 14%, respectively. M o s t of the t r a u m a t r a n s p o r t s have been to t h e t r a u m a center, a n d the adult non-trauma p a t i e n t s have been evenly d i s t r i b u t e d between the two full-service hospitals. Fifteen flights have been to non-sponsoring hospitals. There were 105 missed flights, only 14 of which were due to the equipment b e i n g in use. There have been no accidents. CONCLUSION: We believe this experience d e m o n s t r a t e s t h a t expensive, life-saving resources can be rationally allocated even in t o d a y ' s competitive environment. Our c o m m u n i t y faced the prospect of two or three competing helicopter services w i t h the consequent w a s t e of resources and potential for tragedy. The b r e a d t h and d e p t h of resources of the consortium hospitals h a s created instead a healthy and s t r o n g organization which serves the area well. The risks in aeromedical evacuation can be minimized by i n s u l a t i n g the service from competitive pressure.
Total 116 203 319
CONCLUSIONS: 1) I n a multi-faceted review, a n independent E M S committee found t h a t 24% of t r a u m a cases with ISS scores below 16 were considered valid for t r a n s p o r t to a t r a u m a center. The index of concordance (kappa) between ISS a n d E M S review was .491, p < . 0 0 0 1 . 2 ) A t o t a l of 20 p a t i e n t s {6.3%) were considered inappropriately transported. 3 ) T h e decision to t r a n s p o r t dead-at-scene p a t i e n t s with CPR in progress remains problematic.
30
sake of " c o m p e t i t i o n . " These communities are over-served with superfluous equipment and personnel, a n d the resulting cost is greater t h a n necessary to satisfy the local or regional need. There is also the possibility t h a t under-utilized resources in a competitive e n v i r o n m e n t will generate a pressure for liberalized utilization criteria with a r e s u l t a n t greater cost/need ratio and, more ominously, a relaxation of the safety guidelines necessary in aerotransport. We believe t h a t the helicopter is a n inappro-' priate competitive tool, and t h a t competing institutions can successfully combine to create a common helicopter service which serves the c o m m u n i t y and the participating i n s t i t u t i o n s and averts the hazards of unalloyed competition.
B-3 A R E V I E W OF I N T E R H O S P I T A L C R I T I C A L CARE TRANSPORT PROCEDURES IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION S u s a n L. E l s b e r n d Smith, RN; Joe B. Hejlik, RN; Flight Nurses, Mayo One Helicopter; Larry F. Vukov, MD; Michael B. Farnell, MD; Mayo Medical Center, Saint M a r y s Hospital, Rochester, Minnesota. INTRODUCTION:Nationally, large percentages of p a t i e n t s diagnosed with acute myocardial infarction (AMI) enter rural hospitals a n d require t r a n s p o r t to tertiary care centers for further care. M a n y times these p a t i e n t s are t r a n s f e r r e d b y basic life s u p p o r t (BLS) ambulance services with no t r a i n i n g in critical care life s u p p o r t skills. To determine the n u m b e r a n d frequency of those skills required during transport, the following retrospective s t u d y was performed. M E T H O D S : I n 1986, 96 consecutive p a t i e n t s with the primary diagnosis of A M I were t r a n s f e r r e d from rural hospitals to a t e r t i a r y care center via rotor wing. The n u m b e r of p a t i e n t s requiring one or more critical care skill a n d the n u m b e r of skills performed per p a t i e n t were reviewed. Parenteral medication a d m i n i s t r a t i o n (bolus and drip) and advanced procedures n o t performed b y Minnesota BLS services were included.
RESULTS: Of t h e 96 A M I p a t i e n t s studied: Number of procedures/medications Number of patients affected Required per patient 0 5/(5%) 1-2 39/(41%) 3-4 27 / (28%) 5-6 18/(19%) 7-8 4/(4%) 9-10 3/(3%) Skills Maintained # of Pts. Endotracheal intubation 7 (7%) CVP line 3 (3%) Swan Ganz line 3 (3%) Transvenous pacer 5 (5%) Medications Total no. of IV boluses: 55 Total no. of IV infusions: 131 Total no. of sublingual medications: 9
Skills Performed Enroute Endotracheal intubation External pacing Defibrillation IV insertion IV fluid titration NG insertion
# of Pts. 4 (4%) 7 (7%) 4 (4%) 22 (23%) 40 (42%) 10 (10%)
CONCLUSION: 95% of all p a t i e n t s t r a n s p o r t e d required critical care skills d u r i n g transport, of which 54% required more t h a n three. I n fact, 12 p a t i e n t s (13%) required inflight endotracheal intubation, defibrillation, or external pacing, which were p r o b a b l y life-saving procedures. The i n t e r h o s p i t a l t r a n s p o r t of acute myocardial infarction p a t i e n t s unequivocally suggest m a n a g e m e n t by individuals trained and equipped to provide critical care intervention.
B-4 THE COST-EFFECTIVENESS AND APPROPRIATENESS O F A I R VS. L A N D T R A N S P O R T OF C R I T I C A L T R A U M A AND HEART PATIENTS AMONG HOSPITALS: MADISON, WISCONSIN Michael Bowman, J e r r y Rose, Trudy Karlson, William Perloff, University of Wisconsin Hospital and Clinics, Madison, Wisconsin. INTRODUCTION: The relative costs and effectiveness of inter-hospital critical t r a u m a and h e a r t p a t i e n t s t r a n s p o r t e d b y helicopter a n d b:¢ ground ambulance are not known. The purposes of the s t u d y are to identify a n d compare helicopter costeffectiveness to g r o u n d t r a n s p o r t s cost-effectiveness. M E T H O D S : For 12 m o n t h s inter-hospital t r a u m a a n d h e a r t t r a n s p o r t s b y helicopter a t a major teaching hospital collected b y trained nurse a b s t r a c t o r s are compared with land t r a n s p o r t s d u r i n g the same period and for the previous 36 months. Effectiveness measures are mortality outcomes, a n d changes in severity during transport; cost measures include total costs of t r a n s p o r t a n d costs of hospitalization. Severity measures for h e a r t are Bever, T I S S and the Ischemic H e a r t Disease index. For t r a u m a cases measures were the Bever, TISS, Multiple T r a u m a Severity Index, T r a u m a Score, Multiple I n j u r y Severity Score and Glascow Coma Scale. D a t a are analyzed in crosstabulations, b y least-squares regression and logistic regression. Appropriateness measures are clinical a s s e s s m e n t s of p a t i e n t m a n a g e m e n t b y a panel of four physicians, two external. The analysis was conducted as p a r t of a CON demonstration.
effective. Similar results were found for improvements in severity d u r i n g t r a n s p o r t b y helicopter. For h e a r t patients, there was no i m p r o v e m e n t in mortality and in change in severity b y air. Since t o t a l costs were higher t h a n for land, h e a r t cases were not cost-effective. This s t u d y did not address the impact of air t r a n s p o r t on the early and timely m a n a g e m e n t of cardiac p a t i e n t s whose condition is amenable to invasive therapy such as T-PA a n d angioplasty.
B-5 E V A L U A T I O N OF M I D A Z O L A M (VERSED} I N T H E T R E A T M E N T OF C O M B A T I V E P A T I E N T S I N A E R O M E D I C A L T R A N S P O R T : A P I L O T STUDY Steven Murphey, L y n n Eastes, Gene Viglietta, S a m a r i t a n Air Evac, Phoenix, Arizona. INTRODUCTION: The r e s t r a i n t of combative p a t i e n t s is essential to the safety of the crew a n d efficacy of care in the aeromedical environment. Physical r e s t r a i n t is often inadequate, impractical, or medically undesirable. There exists a need to s t u d y a n d identify a rapid-acting, i n t r a v e n o u s pharmacological r e s t r a i n t to use in these patients. M E T H O D S : A protocol was developed for the r e s t r a i n t and sedation of combative p a t i e n t s in aeromedical transport. In this pilot study, the effectiveness of the new benzodiazapine, Midazolain, was evaluated as a pharmacological restraint. After adm i n i s t r a t i o n of the medication per protocol, the flight nurses completed a questionnaire providing s t u d y data. RESULTS: D u r i n g the s t u d y period, 11 p a t i e n t s were treated with Midazolam. The majority of the sample (N=6) had CNS insults, the remainder (N=) had metabolic or psychiatric etiologies for their combativeness. The m e a n age of the sample was 29 {range 14-53). The suggested s t a r t i n g dose was 1-3 m g slow IV push. M e a n s t a r t i n g dose was 3 m g (range 1-5 rag). In 8 (72%) of the cases, this dose proved a d e q u a t e for sedation. Three p a t i e n t s (27%) required additional medication to achieve the desired sedative effect. One patient was not adequately sedated after receiving 5 mg. Seven 163%) of t h e p a t i e n t s had received prior sedation, m o s t commonly, Diazepam (median dose 20 mg, range 10-100 rag). Four p a t i e n t s (36%) were i n t u b a t e d prior to the a d m i n i s t r a t i o n of Midazolam. Two p a t i e n t s (18%} experienced measurable respiratory depression, one requiring i n t u b a t i o n and one requiring no ventilatory support. No other u n t o w a r d effects were noted. Blood pressures were not assessed immediately before a n d after the a d m i n i s t r a t i o n of t h e Midazolam; however, no sustained hypotensive episodes were noted in the t r a n s p o r t records. Flight nurses reported a 10-15 minute duration of effect in the majority of patients. I n long fixed-wing flights, repeat doses in 2-3 m g increments were sometimes necessary to maintain the desired level of sedation. Mean Total Dose Administered Time of Onset Sedative Effect
Range 7.75 m g 2.7 min
2.5-10 m g .75-10 min
CONCLUSIONS: Midazolam proved to be a safe a n d effective m e t h o d of pharmacological r e s t r a i n t in this pilot study. Midazolam's rapid onset, s h o r t duration of action, and minimal respiratory depressive effects makes this drug an excellent choice for sedating combative p a t i e n t s during aeromedical transport.
R E S U L T S A N D CONCLUSIONS: Over 85 percent of the helicopter t r a n s p o r t s were judged appropriate b y a conservative rule. For t r a u m a patients, helicopter t r a n s p o r t showed a 23 to 32 percent decrease in severity-adjusted mortality, compared to land (p< .05). Since the total costs of air p a t i e n t s were equal to land costs, this is evidence t h a t helicopter t r a n s p o r t is cost-
A~$
SEPTEMBER/OCTOBER1987
31