- Email: [email protected]
Use of a physiologic scoring system during interhospital transport of pediatric patients
Use of a Physiologic Scoring System during Interhospital Transport of Pediatric Patients Björn Gunnarsson, MD,1 Christopher M.B. Heard, MB, ChB,1 Alexandre T. Rotta, MD,1 Andrew M.B. Heard, MB, ChB,2 Barbara H. Kourkounis, RN,1 and James E. Fletcher, MB, BS3
ABSTRACT Objective: To determine the incidence of physiologic deterioration in critically ill and injured pediatric patients during interhospital transport with air and ground ambulance Design: Prospective, descriptive study Setting: All children were treated in regional hospitals and then transported to a pediatric tertiary care center. Patients: Children (n = 100) with a median age of 1.4 years (range 1 week to 18 years) Main results: Three sets of physiologic scores were calculated: at the time of referral, on departure from the referring hospital, and arrival at the tertiary care center. The incidence of significant physiologic deterioration based on the calculated physiologic scores was 5.6% (n = 4) during ground and 3.4% (n = 1) during air ambulance transports. Critical events occurred in 15% of ground and 31% of air ambulance transports. Conclusion: No difference existed in the incidence of adverse events or physiologic deterioration when air ambulance transports were compared with ground ambulance transports for critically ill children by our team. The physiologic scoring system we chose is simple and easy to use for quality assurance.
Introduction The transport of critically ill or injured children for medical care is an important capability of regional health care systems. The objective of pediatric transport teams is to reach children in need, stabilize them if necessary, and transport them promptly and safely to an appropriate facility. Morbidity and mortality are less likely when these children are hospitalized in regional pediatric critical care centers than local community hospitals.1,2 This approach calls for an effective and safe transportation of patients to regional critical care centers, which usually are tertiary care centers staffed with pediatric specialists. However, certain risks are associated with interhospital transport.3-5 Physiologic stability may not have been established before transport, and the environment in the ambulance is unfavorable for emergency care. Adverse events and physiologic deterioration during transport may be more common during air ambulance transports as a result of the very limited workspace, noise, vibration, cabin pressure changes, greater acceleration, and logistical complexity. This study compared the physiologic stability of pediatric patients during ground and air transport by using a sequential physiology scoring system.
ferred to the Children’s Hospital of Buffalo (CHOB) from other hospitals in western New York from January 1997 to August 1998. Transport personnel provided by CHOB consisted of a nurse and, in some cases, a respiratory therapist, emergency medical technician, or a fellow in either pediatric critical care or pediatric emergency medicine. For each patient transported by the pediatric transport team, these data were collected prospectively and entered into a computer database: age, weight, diagnoses, time taken for travel, staff utilization, and mode of transport. A physiology score was recorded on three occasions: on referral to the transport team, departure from the referring hospital, and arrival at CHOB. This score was based on physiologic parameters derived from the Pediatric Risk of Mortality (PRISM) scoring system,6 as has been previously described.7 We considered an increase of more than 2 in the physiology score during the transport to be significant physiologic deterioration. All interventions performed by the referring hospital and the transport team before and during transport were registered and an intervention score applied using 14 of the Therapeutic Intervention Scoring System (TISS) scoring parameters.8 Table 1 shows the physiologic measurements and intervention parameters recorded. We also documented whether any critical incidents occurred during the transport.9
1. Children’s Hospital of Buffalo, Buffalo, N.Y. 2. Manchester Royal Infirmary, Manchester, England 3. University of North Carolina, Chapel Hill, N.C. Address for correspondence: Christopher M.B. Heard, MB, ChB, Department of Anesthesia, Children’s Hospital of Buffalo, 219 Bryant St., Buffalo, NY 14222, [email protected] Key words: clinical scoring systems, critical care illness, patient outcome assessment, Pediatric Risk of Mortality (PRISM), pediatrics, Therapeutic Intervention Scoring System (TISS), transportation of patients Acknowledgment: We would like to express our gratitude to the transport nurses at CHOB for recording the data for this study. Copyright © 2001 by Air Medical Journal Associates 1067-991X/2001/$35.00 + 0 Reprint no. 74/1/116991
Methods
doi:10.1067/mmj.2001.116991
We studied interhospital transports of pediatric patients reJuly-August 2001
23
Table 1. Physiologic Measurements, Intervention Parameters, and Critical Incidents Recorded Physiologic measurements
Interventions
Critical incidents
Blood pressure Heart rate Respiratory rate Temperature PaO2 FiO2 Pulse oximetry Pupillary response
Intubation Mechanical ventilation Peripheral venous access Central venous access Arterial access Fluid bolus Blood transfusion Sedation Paralysis Inotropes Blood gas
Respiratory arrest Cardiac arrest Hypotension Oxygen saturation < 90% Glasgow Coma Score < 8 Arrhythmia Unintended extubation Blocked endotracheal tube Aspiration of gastric contents Loss of oxygen supply Loss of vascular access Temperature < 34.5° C
Table 2.
Demographics, Physiology, and Intervention Scores
Demographic Number of patients Age (years) Weight (kg) MD on transport team Time to mobilize team (mins) Time at referring hospital (mins) Return transport time (mins) Physiology score on referral Physiology score before transport Physiology score on arrival at CHOB Total intervention score Critical incidents Data are median 95% CI.
Ground 71 1.4 ± 0.6 11.2 ± 2.8 36 (51%) 20 ± 4 30 ± 4 45 ± 6.5 4.0 ± 1.2 3.0 ± 0.9 3.0 ± 0.8 3.0 ± 2.2 11 (15%)
Air 29 2.2 ± 1.2 16.8 ± 18.6 18 (62%) 35 ± 9 35 ± 6 45 ± 6 3.0 ± 1.7 3.0 ± 1.6 0.0 ± 0.9 3.0 ± 2.8 9 (31%)
P 0.88 0.62 0.66 0.002 0.12 0.71 0.12 0.55 0.17 0.78 0.14
Table 3. Percentage of Patients Showing Improvement or Deterioration in Physiology Score during Transport Process (Time of Referral to Arrival at CHOB) Deterioration ( 2 points) No significant change Improvement ( 2 points)
Ground 5.6% 78.9% 15.5%
Because of considerable skewing of the data, statistical analysis of unpaired data used the Mann-Whitney U-test, and paired data were analyzed with the Wilcoxon Rank Sum test. Data are presented as median 95% CI of the median. Statistical significance was defined as P < 0.05.
Results Data were collected prospectively from 100 patients transported by the CHOB pediatric transport team during a period of 18 months. Patient demographics and physiology and intervention scores are shown in Table 2. Of the transports, 71 were by 24
Air 3.5% 79.3% 17.2%
P 0.96 0.99 0.93
ground and 29 by air (four fixed wing, 25 helicopter). Patients transported by ground and air ambulances were of similar age and weight. Figure 1 shows the time taken to mobilize the transport team, the time the team spent at the referring hospital stabilizing the patient, and time spent with the patient en route to CHOB. Significantly more time was spent mobilizing the transport team at CHOB for air ambulance transports than for ground. No difference existed, however, in return transport times between ground and air transports. Each of the physiology scores for the two groups are shown in Figure 2. No significant difference occurred in physiology Air Medical Journal 20:4
Figure 2. Comparison of Physiology Scores Figure 1. Transport Times Times divided by method of transport (ground or air) at the three stages of transport: mobilizing the transport team, time spent stabilizing the patient at the referring hospital, and actual air or ground (one way) transport time. Data are median, 25th/75th percentile (box), and 10th/90th percentile (bars). * P < 0.05 compared with ground at same stage of transportation.
Scores divided by method of transport (ground or air) at three time points: time of referral by report of the referring team, departure of the transport team with the patient from the referring hospital, and arrival of the patient at the base hospital (CHOB). Data are median, 25th/75th percentile (box), and 10th/90th percentile (bars). * P < 0.05 compared with previous physiology score in same transport group. P < 0.05 compared with physiology score on referral of patient in same transport group.
scores between the groups at any of the three time points. Physiology scores did improve, however, during the whole transport process for both modes of transport. Table 3 shows the change in physiology scores from baseline for each group; Figure 3 illustrates the number of patients showing improvement or deterioration in physiologic score during transport. Only four of the 71 patients transported by ground experienced significant physiologic deterioration (5.6%), and one of the 29 patients transported by air ambulance (3.4%, P = 0.96) deteriorated. The total intervention scores for both groups were not significantly different. Critical incidents occurred during 11 (15%) ground transports and nine (31%) air transports (P = 0.14). These incidents were most commonly a transient fall in the oxygen saturation < 90% (n = 7), hyperthermia (n = 3), and hypotension (n = 3). No patient died during the transport process.
Discussion The main purpose of this study was to use serial physiology scores prospectively to compare the incidence of physiologic deterioration in pediatric patients transported by ground ambulance with that of children transported by air ambulance. We are not aware of other studies that have compared the incidence of patient deterioration and adverse events during air and ground transport. Our helicopter is dispatched from a site remote from the hospital, which means all patients transported by air are moved from the aircraft to an ambulance for a 10- to 20-minute ride to our hospital. We were suspicious that adverse events might be caused by this practice and the difficulty of assessing the patient during air transport, especially in a helicopter. By applying a PRISM-based scoring system, we were unable to detect a significant difference in the physiologic stability during transport of a group of patients transported by ground compared with air ambulance. We did note, however, an overall improvement in July-August 2001
Patient deterioration is represented by a negative number.
Figure 3. Number of Patients Showing Improvement or Deterioration in Physiology Score during Transport.
physiologic scores during transport in both groups. The incidence of critical events was high in both groups. Cray et al.7 reported an 8% incidence of critical incidents during ground ambulance transportation in England using the same criteria we did. Another study from England3 reported a 70% incidence of adverse clinical events and 23% incidence of potentially life-threatening adverse incidents during mostly ground transports of pediatric patients. These differences may be explained by many factors, including differences in patient population and transport team composition. 25
We found that the time taken for the transport team to mobilize from the base hospital and prepare the patient for return from the referring hospital was longer with the air ambulance. This was a reflection of the logistic complexities of arranging air transport at our institution. This time difference also may be explained, at least in part, by the fact the physicians went more often on air transports than ground transports. Unlike transport nurses, transport physicians are not always stationed at the hospital, and waiting for them can delay departure. The slightly longer time spent at the referring hospital with air transport cannot be attributed to patient intervention because the frequency of interventions at the referring site was not different between the two groups studied. Some of the time difference may be explained by the transport team being a little more cautious in preparations for the return journey. That no difference occurred in actual transport time probably reflects an appropriate selection of transport mode based on geographic factors. Study limitations include the small number of patients in the air ambulance group. Statistical analysis was performed using nonparametric tests, which also weakens the results. Although we did not attempt to validate the assessment tool we used, prior experience with the use of this scoring system and other systems has been described.7,10 We believe this scoring system can be of value for quality assurance for the transport team. We acknowledge that the information obtained at the time of transport request often is unreliable. Several studies have shown that PRISM scores at the time of referral underestimate the severity of illness.11,12 Pretransport PRISM also has been shown to be a poor indicator of physiologic stability.11,13 We, however, found a good correlation between the physiologic assessment done by the referring hospital staff and our transport team’s initial assessment. We conclude that, for critically ill children transported by our transport team, no difference exists in the incidence of ad-
26
verse events or physiologic deterioration when air ambulance transports are compared with ground ambulance transports. The physiologic scoring system we chose is simple and easy to use for quality assurance.
References 1. Pollack MM, Alexander SR, Clarke N, Ruttimann UE, Tesselaar HM, Bachulis AC. Improved outcomes from tertiary center pediatric intensive care: a statewide comparison of tertiary and nontertiary care facilities. Crit Care Med 1991;19:150-9. 2. Pearson G, Shann F, Barry P, Vyas J, Thomas D, Powell C, et al. Should paediatric intensive care be centralised? Trent versus Victoria. Lancet 1997;349:1213-7. 3. Barry PW, Ralston C. Adverse events occurring during interhospital transfer of the critically ill. Arch Dis Child 1994;71(1):8-11. 4. Britto J, Nadel S, Maconochie I, Levin M, Habibi P. Morbidity and severity of illness during interhospital transfer: impact of a specialised paediatric retrieval team. Br Med J 1995;311:836-9. 5. Kanter RK, Boeing NM, Hannan WP, Kanter DL. Excess morbidity associated with interhospital transport. Pediatrics 1992;90:893-8. 6. Pollack MM, Ruttimann UE, Getson PR. Pediatric risk of mortality (PRISM) score. Crit Care Med 1988;16:1110-6. 7. Cray SH, Heard CM. Transport for paediatric intensive care. Measuring the performance of a specialist transport service. Paediatr Anaesth 1995;5:287-92. 8. Cullen DJ, Civetta JM, Briggs BA, Ferrara LC. Therapeutic Intervention Scoring System: a method for quantitative comparison of patient care. Crit Care Med 1974;2(2):57-60. 9. Kanter RK, Tompkins JM. Adverse events during interhospital transport: physiologic deterioration associated with pretransport severity of illness. Pediatrics 1989;84(1):43-8. 10. Rhee KJ, Mackenzie JR, Burney RE, Willits NH, O’Malley RJ, Reid N, et al. Rapid acute physiology scoring in transport systems. Crit Care Med 1990:18:1119-23. 11. Orr RA, Venkataraman ST, Cinoman MI, Hogue BL, Singleton CA, McCloskey KA. Pretransport Pediatric Risk of Mortality (PRISM) score underestimates the requirement for intensive care or major interventions during interhospital transport. Crit Care Med 1994 22:101-7. 12. Whitfield JM, et al. The telephone evaluation of severity of illness of the neonatal/pediatric patient prior to interhospital transfer [abstract]. J Air Med Transport 1991;10:82. 13. Britto J, Nadel S, Habibi P, Levin M. Pediatric risk of mortality score underestimates the requirement for intensive care during interhospital transport. Crit Care Med 1994;22:2029-30.
Air Medical Journal 20:4
ABSTRACT Objective: To determine the incidence of physiologic deterioration in critically ill and injured pediatric patients during interhospital transport with air and ground ambulance Design: Prospective, descriptive study Setting: All children were treated in regional hospitals and then transported to a pediatric tertiary care center. Patients: Children (n = 100) with a median age of 1.4 years (range 1 week to 18 years) Main results: Three sets of physiologic scores were calculated: at the time of referral, on departure from the referring hospital, and arrival at the tertiary care center. The incidence of significant physiologic deterioration based on the calculated physiologic scores was 5.6% (n = 4) during ground and 3.4% (n = 1) during air ambulance transports. Critical events occurred in 15% of ground and 31% of air ambulance transports. Conclusion: No difference existed in the incidence of adverse events or physiologic deterioration when air ambulance transports were compared with ground ambulance transports for critically ill children by our team. The physiologic scoring system we chose is simple and easy to use for quality assurance.
Introduction The transport of critically ill or injured children for medical care is an important capability of regional health care systems. The objective of pediatric transport teams is to reach children in need, stabilize them if necessary, and transport them promptly and safely to an appropriate facility. Morbidity and mortality are less likely when these children are hospitalized in regional pediatric critical care centers than local community hospitals.1,2 This approach calls for an effective and safe transportation of patients to regional critical care centers, which usually are tertiary care centers staffed with pediatric specialists. However, certain risks are associated with interhospital transport.3-5 Physiologic stability may not have been established before transport, and the environment in the ambulance is unfavorable for emergency care. Adverse events and physiologic deterioration during transport may be more common during air ambulance transports as a result of the very limited workspace, noise, vibration, cabin pressure changes, greater acceleration, and logistical complexity. This study compared the physiologic stability of pediatric patients during ground and air transport by using a sequential physiology scoring system.
ferred to the Children’s Hospital of Buffalo (CHOB) from other hospitals in western New York from January 1997 to August 1998. Transport personnel provided by CHOB consisted of a nurse and, in some cases, a respiratory therapist, emergency medical technician, or a fellow in either pediatric critical care or pediatric emergency medicine. For each patient transported by the pediatric transport team, these data were collected prospectively and entered into a computer database: age, weight, diagnoses, time taken for travel, staff utilization, and mode of transport. A physiology score was recorded on three occasions: on referral to the transport team, departure from the referring hospital, and arrival at CHOB. This score was based on physiologic parameters derived from the Pediatric Risk of Mortality (PRISM) scoring system,6 as has been previously described.7 We considered an increase of more than 2 in the physiology score during the transport to be significant physiologic deterioration. All interventions performed by the referring hospital and the transport team before and during transport were registered and an intervention score applied using 14 of the Therapeutic Intervention Scoring System (TISS) scoring parameters.8 Table 1 shows the physiologic measurements and intervention parameters recorded. We also documented whether any critical incidents occurred during the transport.9
1. Children’s Hospital of Buffalo, Buffalo, N.Y. 2. Manchester Royal Infirmary, Manchester, England 3. University of North Carolina, Chapel Hill, N.C. Address for correspondence: Christopher M.B. Heard, MB, ChB, Department of Anesthesia, Children’s Hospital of Buffalo, 219 Bryant St., Buffalo, NY 14222, [email protected] Key words: clinical scoring systems, critical care illness, patient outcome assessment, Pediatric Risk of Mortality (PRISM), pediatrics, Therapeutic Intervention Scoring System (TISS), transportation of patients Acknowledgment: We would like to express our gratitude to the transport nurses at CHOB for recording the data for this study. Copyright © 2001 by Air Medical Journal Associates 1067-991X/2001/$35.00 + 0 Reprint no. 74/1/116991
Methods
doi:10.1067/mmj.2001.116991
We studied interhospital transports of pediatric patients reJuly-August 2001
23
Table 1. Physiologic Measurements, Intervention Parameters, and Critical Incidents Recorded Physiologic measurements
Interventions
Critical incidents
Blood pressure Heart rate Respiratory rate Temperature PaO2 FiO2 Pulse oximetry Pupillary response
Intubation Mechanical ventilation Peripheral venous access Central venous access Arterial access Fluid bolus Blood transfusion Sedation Paralysis Inotropes Blood gas
Respiratory arrest Cardiac arrest Hypotension Oxygen saturation < 90% Glasgow Coma Score < 8 Arrhythmia Unintended extubation Blocked endotracheal tube Aspiration of gastric contents Loss of oxygen supply Loss of vascular access Temperature < 34.5° C
Table 2.
Demographics, Physiology, and Intervention Scores
Demographic Number of patients Age (years) Weight (kg) MD on transport team Time to mobilize team (mins) Time at referring hospital (mins) Return transport time (mins) Physiology score on referral Physiology score before transport Physiology score on arrival at CHOB Total intervention score Critical incidents Data are median 95% CI.
Ground 71 1.4 ± 0.6 11.2 ± 2.8 36 (51%) 20 ± 4 30 ± 4 45 ± 6.5 4.0 ± 1.2 3.0 ± 0.9 3.0 ± 0.8 3.0 ± 2.2 11 (15%)
Air 29 2.2 ± 1.2 16.8 ± 18.6 18 (62%) 35 ± 9 35 ± 6 45 ± 6 3.0 ± 1.7 3.0 ± 1.6 0.0 ± 0.9 3.0 ± 2.8 9 (31%)
P 0.88 0.62 0.66 0.002 0.12 0.71 0.12 0.55 0.17 0.78 0.14
Table 3. Percentage of Patients Showing Improvement or Deterioration in Physiology Score during Transport Process (Time of Referral to Arrival at CHOB) Deterioration ( 2 points) No significant change Improvement ( 2 points)
Ground 5.6% 78.9% 15.5%
Because of considerable skewing of the data, statistical analysis of unpaired data used the Mann-Whitney U-test, and paired data were analyzed with the Wilcoxon Rank Sum test. Data are presented as median 95% CI of the median. Statistical significance was defined as P < 0.05.
Results Data were collected prospectively from 100 patients transported by the CHOB pediatric transport team during a period of 18 months. Patient demographics and physiology and intervention scores are shown in Table 2. Of the transports, 71 were by 24
Air 3.5% 79.3% 17.2%
P 0.96 0.99 0.93
ground and 29 by air (four fixed wing, 25 helicopter). Patients transported by ground and air ambulances were of similar age and weight. Figure 1 shows the time taken to mobilize the transport team, the time the team spent at the referring hospital stabilizing the patient, and time spent with the patient en route to CHOB. Significantly more time was spent mobilizing the transport team at CHOB for air ambulance transports than for ground. No difference existed, however, in return transport times between ground and air transports. Each of the physiology scores for the two groups are shown in Figure 2. No significant difference occurred in physiology Air Medical Journal 20:4
Figure 2. Comparison of Physiology Scores Figure 1. Transport Times Times divided by method of transport (ground or air) at the three stages of transport: mobilizing the transport team, time spent stabilizing the patient at the referring hospital, and actual air or ground (one way) transport time. Data are median, 25th/75th percentile (box), and 10th/90th percentile (bars). * P < 0.05 compared with ground at same stage of transportation.
Scores divided by method of transport (ground or air) at three time points: time of referral by report of the referring team, departure of the transport team with the patient from the referring hospital, and arrival of the patient at the base hospital (CHOB). Data are median, 25th/75th percentile (box), and 10th/90th percentile (bars). * P < 0.05 compared with previous physiology score in same transport group. P < 0.05 compared with physiology score on referral of patient in same transport group.
scores between the groups at any of the three time points. Physiology scores did improve, however, during the whole transport process for both modes of transport. Table 3 shows the change in physiology scores from baseline for each group; Figure 3 illustrates the number of patients showing improvement or deterioration in physiologic score during transport. Only four of the 71 patients transported by ground experienced significant physiologic deterioration (5.6%), and one of the 29 patients transported by air ambulance (3.4%, P = 0.96) deteriorated. The total intervention scores for both groups were not significantly different. Critical incidents occurred during 11 (15%) ground transports and nine (31%) air transports (P = 0.14). These incidents were most commonly a transient fall in the oxygen saturation < 90% (n = 7), hyperthermia (n = 3), and hypotension (n = 3). No patient died during the transport process.
Discussion The main purpose of this study was to use serial physiology scores prospectively to compare the incidence of physiologic deterioration in pediatric patients transported by ground ambulance with that of children transported by air ambulance. We are not aware of other studies that have compared the incidence of patient deterioration and adverse events during air and ground transport. Our helicopter is dispatched from a site remote from the hospital, which means all patients transported by air are moved from the aircraft to an ambulance for a 10- to 20-minute ride to our hospital. We were suspicious that adverse events might be caused by this practice and the difficulty of assessing the patient during air transport, especially in a helicopter. By applying a PRISM-based scoring system, we were unable to detect a significant difference in the physiologic stability during transport of a group of patients transported by ground compared with air ambulance. We did note, however, an overall improvement in July-August 2001
Patient deterioration is represented by a negative number.
Figure 3. Number of Patients Showing Improvement or Deterioration in Physiology Score during Transport.
physiologic scores during transport in both groups. The incidence of critical events was high in both groups. Cray et al.7 reported an 8% incidence of critical incidents during ground ambulance transportation in England using the same criteria we did. Another study from England3 reported a 70% incidence of adverse clinical events and 23% incidence of potentially life-threatening adverse incidents during mostly ground transports of pediatric patients. These differences may be explained by many factors, including differences in patient population and transport team composition. 25
We found that the time taken for the transport team to mobilize from the base hospital and prepare the patient for return from the referring hospital was longer with the air ambulance. This was a reflection of the logistic complexities of arranging air transport at our institution. This time difference also may be explained, at least in part, by the fact the physicians went more often on air transports than ground transports. Unlike transport nurses, transport physicians are not always stationed at the hospital, and waiting for them can delay departure. The slightly longer time spent at the referring hospital with air transport cannot be attributed to patient intervention because the frequency of interventions at the referring site was not different between the two groups studied. Some of the time difference may be explained by the transport team being a little more cautious in preparations for the return journey. That no difference occurred in actual transport time probably reflects an appropriate selection of transport mode based on geographic factors. Study limitations include the small number of patients in the air ambulance group. Statistical analysis was performed using nonparametric tests, which also weakens the results. Although we did not attempt to validate the assessment tool we used, prior experience with the use of this scoring system and other systems has been described.7,10 We believe this scoring system can be of value for quality assurance for the transport team. We acknowledge that the information obtained at the time of transport request often is unreliable. Several studies have shown that PRISM scores at the time of referral underestimate the severity of illness.11,12 Pretransport PRISM also has been shown to be a poor indicator of physiologic stability.11,13 We, however, found a good correlation between the physiologic assessment done by the referring hospital staff and our transport team’s initial assessment. We conclude that, for critically ill children transported by our transport team, no difference exists in the incidence of ad-
26
verse events or physiologic deterioration when air ambulance transports are compared with ground ambulance transports. The physiologic scoring system we chose is simple and easy to use for quality assurance.
References 1. Pollack MM, Alexander SR, Clarke N, Ruttimann UE, Tesselaar HM, Bachulis AC. Improved outcomes from tertiary center pediatric intensive care: a statewide comparison of tertiary and nontertiary care facilities. Crit Care Med 1991;19:150-9. 2. Pearson G, Shann F, Barry P, Vyas J, Thomas D, Powell C, et al. Should paediatric intensive care be centralised? Trent versus Victoria. Lancet 1997;349:1213-7. 3. Barry PW, Ralston C. Adverse events occurring during interhospital transfer of the critically ill. Arch Dis Child 1994;71(1):8-11. 4. Britto J, Nadel S, Maconochie I, Levin M, Habibi P. Morbidity and severity of illness during interhospital transfer: impact of a specialised paediatric retrieval team. Br Med J 1995;311:836-9. 5. Kanter RK, Boeing NM, Hannan WP, Kanter DL. Excess morbidity associated with interhospital transport. Pediatrics 1992;90:893-8. 6. Pollack MM, Ruttimann UE, Getson PR. Pediatric risk of mortality (PRISM) score. Crit Care Med 1988;16:1110-6. 7. Cray SH, Heard CM. Transport for paediatric intensive care. Measuring the performance of a specialist transport service. Paediatr Anaesth 1995;5:287-92. 8. Cullen DJ, Civetta JM, Briggs BA, Ferrara LC. Therapeutic Intervention Scoring System: a method for quantitative comparison of patient care. Crit Care Med 1974;2(2):57-60. 9. Kanter RK, Tompkins JM. Adverse events during interhospital transport: physiologic deterioration associated with pretransport severity of illness. Pediatrics 1989;84(1):43-8. 10. Rhee KJ, Mackenzie JR, Burney RE, Willits NH, O’Malley RJ, Reid N, et al. Rapid acute physiology scoring in transport systems. Crit Care Med 1990:18:1119-23. 11. Orr RA, Venkataraman ST, Cinoman MI, Hogue BL, Singleton CA, McCloskey KA. Pretransport Pediatric Risk of Mortality (PRISM) score underestimates the requirement for intensive care or major interventions during interhospital transport. Crit Care Med 1994 22:101-7. 12. Whitfield JM, et al. The telephone evaluation of severity of illness of the neonatal/pediatric patient prior to interhospital transfer [abstract]. J Air Med Transport 1991;10:82. 13. Britto J, Nadel S, Habibi P, Levin M. Pediatric risk of mortality score underestimates the requirement for intensive care during interhospital transport. Crit Care Med 1994;22:2029-30.
Air Medical Journal 20:4