Management and outcomes of pediatric patients transported by emergency medical services in a Canadian prehospital system

Pediatrics

CJEM 2006;8(1):6-12

Abstract

Résumé

Introduction

Children account for 5%-10% of the overall emergency medical services (EMS) transport population.^1-3 Pediatric EMS utilization has been well described in the United States,^1-11 but there is no Canadian population-based research describing the use of EMS for children; consequently the population characteristics, prehospital interventions provided and their impact on patient outcomes are unknown.

There has been debate and uncertainty regarding the role of pediatric ambulance services. Some authors note the high proportion of inappropriate EMS transports for non-urgent patients,^12-14 and in one report the authors described the majority of pediatric ambulance transports as being a medically unnecessary "taxi service."¹⁵ Other studies have pointed out important EMS interventions that are under-used among children, such as aggressive treatment for respiratory distress and seizure.^16,17 It has also been noted that a large proportion of critically ill or injured children who present to the emergency department (ED) do not use the EMS system.¹⁸

The current investigation is a substudy of the Ontario Prehospital Advanced Life Support (OPALS) Study.¹⁹ The OPALS study used a before-after clinical trial design to assess the sequential introduction of 2 specific interventions: rapid defibrillation (phase II),²⁰ and Advanced Life Support (ALS) including intubation and intravenous drug therapy (phase III).²¹ Within this framework, after the implementation of ALS, we conducted an observational cohort study to examine pediatric EMS transports. The specific EMS interventions studied were endotracheal intubation, bag-valve-mask ventilation, establishment of an intravenous (IV) line, and the provision of IV medications.

Our objective was to describe the pattern of pediatric EMS use in a single Ontario region, including patient characteristics, prehospital interventions used and patient outcomes. Children with seizures were identified as an a priori subgroup; we hypothesized that these patients may be more likely to require EMS intervention. This information will be important in identifying areas in which to focus EMS pediatric training. It will also inform future planning for pediatric prehospital intervention trials.

Methods

Setting

This prospective cohort study was conducted in Ottawa, Canada, which has a population of 750.000 and a 2-tiered EMS response system, including Basic Life Support with Defibrillation (BLS-D) and ALS. This system is a combined rural and urban service with a catchment area of 2757 km², operating from 8 rural stations and a central urban station. High-density areas, with 24 or more responses per square kilometer per year, accounted for 14.3% of the study region, while low-density areas comprised 85.7% of the region. The vast majority of children are transported directly to the tertiary care pediatric hospital ED; however, those with compromised airway, breathing or circulation are transported to the closest hospital. In addition, children with less urgent conditions may be transported to 1 of 2 community hospitals in the region.

Patients and calls

All children under 16 years of age who were assessed by prehospital personnel during a 6-month period (Apr. 1 to Sept. 30, 2001) were identified, using the common ambulance call report used throughout the province of Ontario. Eligible patient encounters were identified using ambulance call reports collected from the base hospital program for the period of the study. Cases were excluded if pick-up location did not fall within the pre-determined geographic catchment area, or if the EMS service was used for a between-hospital, or air-to-hospital transfer.

The following EMS Return Priority Codes were assigned by paramedics: Urgent, for calls requiring immediate transport because of life or limb threat; Prompt for calls involving serious illness or injury; and Deferrable for routine calls that could be delayed without being detrimental to the patient.

Data collection

Patient demographics, EMS assessment of return priority, location of patient pick-up, reason stated by paramedics for parental or guardian refusal of transport, patient's primary problem as stated by paramedics, and prehospital procedures performed by paramedics were abstracted from the ambulance call reports. Emergency department disposition and final diagnosis were gathered by reviewing relevant hospital charts. We attempted no follow-up of children who were not transported by EMS.

All abstracted data were transferred to a structured data collection form, including date, relevant dispatch, scene, and transport times, patient age and gender, return priority code, patient status on arrival at ED, and chief complaint as determined by the EMS classification system. The data were then entered into a database using SAS Version 8.

Data analysis

Descriptive statistics, including means and standard deviations (SDs) for continuous variables and percentages for categorical variables, were calculated. Patients with seizures were identified as an a priori subgroup; these data were included in the primary analysis and in pre-defined subgroup analyses. Data analysis was performed using SAS Version 8. The study was approved by the Hospital Research Ethics Board.

Results

During the 6-month study period there were 30.793 EMS calls, of which 1377 (4.6%) involved patients under the age of 16. Table 1 shows that mean age in the study population was 8.2 years (SD = 5.4) and that 57% were male. A bimodal distribution was evident with more frequent calls for children under the age of 2 years and over the age of 13 (Fig. 1). For children under age 2, medical problems dominated, accounting for 75.9% of calls; whereas over age 9, injuries and trauma were more common (54.3% of calls). Minor trauma was the most frequent reason for EMS activation (44% of calls), followed by seizures (12%) and respiratory distress (9%). The remaining cases reflected a wide range of medical problems. Eleven children suffered major trauma (Injury Severity Score >11), and there was 1 child with cardiac arrest. Most EMS responses were to a place of residence (52%), a public place (18%) or a street (17%).

Of those children assessed by EMS, 7% were judged to require Urgent transport to the hospital, 57% required Prompt transport, 8% were considered Deferrable and 28% were Not Transported to the hospital (Table 2). This relatively high non-transport rate was similar to the non-transport rate of the total EMS call population, which was 31.6% (9728 of 30.793 calls). In over half of the pediatric non-transport cases, no reason was documented. In many cases, the guardian indicated they would transport the child to hospital themselves (24%) or monitor the child's condition at home (17%). In 3% of cases, ambulance attendants deferred the transport to another EMS crew or to helicopter. Table 2 also shows that mean response time from "call receipt to vehicle stops" was 11.0 minutes and the mean time at the scene from "vehicle stops to depart scene" was 15.9 minutes. Mean travel time from scene to hospital was 16 minutes.

Vitals signs were recorded on the majority of patients. Heart rate was documented in 1221 (88.7%), respiratory rate in 1235 (89.7%), systolic blood pressure in 756 (54.9%), and diastolic blood pressure in 552 (40.1%). Most responses (62%) involved an advanced care paramedic. Table 3 summarizes prehospital interventions, showing that 767 children (56% of those assessed) received one or more interventions and 44.0% received none. In the intervention group, 598 (43.4%) received at least 1 BLS intervention and 368 (26.7%) received at least 1 ALS intervention (Table 3).

Fig. 1. Age distribution of pediatric prehospital patients (n = 1377).

Of the 992 transported patients, 896 (90.3%) were transported to the tertiary care pediatric hospital, 69 (7.0%) to community hospitals and 27 (2.7%) to adult tertiary care hospitals. Patient status on arrival to ED was documented in 814 of 992 (82%) transported cases. Of those documented, the patient's status improved during transport in 41%, was unchanged in 58% and deteriorated in 1%.

Table 4 provides a summary of outcomes, showing that most patients (82.6%) were discharged home after ED treatment, that 89 children (9.0%) were admitted to the hospital and 22 (2.2%) were admitted to the intensive care unit (ICU). The admitted patients had a mean hospital length of stay of 8.4 days (SD 15.7). The final diagnosis for hospitalized children was most often related to trauma (30.4%), respiratory illness (18.0%) or psychiatric illness (12.4%). During the study period, only 1 child suffered a cardiac arrest (i.e., vital signs absent). There were no deaths in the study cohort; however, follow-up data could not be obtained for 41 cases (4.1%).

Seizures were the most common non-injury-related reason for transport (n = 162; 11.8%). Seizure-related calls were most often to a residence (79%), a public place (9.3%) or a school (7.4%). Mean age in this group was 5.4 years (SD = 4.8) and, based on EMS determination, 63 children (39%) had febrile seizures, 33 (20%) had "new-onset, non-febrile seizure" and 59 (36%) had a chronic seizure disorder. The seizure ended before EMS arrival in 135 cases (83%), while EMS was at the scene in 3 (1.9%), and on route to hospital in 7 cases (4.3%). Of the 162 children with seizures, 143 (88%) were transported to hospital and only 5 (3%) were still convulsing at the time of ED arrival.

Basic Life Support interventions included blood glucose measurement in 114 (70%), oxygen in 98 (60%), suction in 5 (3%) and bag-valve-mask ventilation in 2 (1%). Advanced Life Support interventions included cardiac monitoring in 79 (49%), IV access (attempted in 47 cases; successful in 32) and diazepam administration 10 (6%). No patients required endotracheal intubation. Of the 143 transported children, 128 (90%) were discharged home from the ED, 8 (6%) were admitted to the ward and 1 (0.7%) was admitted to the ICU, with 6 patients (4%) lost to follow-up.

Discussion

This is the first Canadian study of the epidemiology of pediatric prehospital care that describes EMS interventions and outcomes. Our data showed that minor trauma, including fractures, head injuries and lacerations, is the most common reason for EMS transport, followed by seizures and respiratory distress. Most children received BLS or ALS interventions, but ALS interventions other than cardiac monitoring were rare. Most transports were not urgent and the admission rate to hospital was relatively low. In addition, many children were assessed by EMS but not transported to hospital.

In this study, children represented only 4.6% of paramedic calls, lower than the 10% reported in other studies and commonly quoted in prehospital and medical literature.^1,2,22 However, these studies included patients up to 19 years of age, and many of these "pediatric" patients are actually of adult size and physiology. Our study is similar to those by McCaig and Ly³ and by Joyce and colleagues,⁴ who defined "pediatric" as <15 years old, and found that pediatric transports accounted for 4% to 5.4% of all ambulance transports. Our finding of a bimodal age distribution is consistent with findings of Tsai and Kallsen² who also found an early (largely medical) peak in the first year of life and a second peak in the teenage years, which consisted largely of trauma cases.

The study data also indicate that 93% of pediatric ambulance transports were non-urgent and that 99% of those transported to the ED were stable or improved after ambulance transport. Admissions to hospital were also low, at 9.0%; however, of those admitted, 24.7% required admission to the ICU. These findings are consistent with previous studies.^4,8,15,18 Ironically, Kost and colleagues¹⁸ found that 87% of high-acuity pediatric cases arrived by private vehicle, suggesting that ambulance services may sometimes be used inappropriately to transport low-acuity patients, while many high-acuity patients are transported by other means.

The vast majority of interventions provided involved providing oxygen, measuring blood glucose, immobilizing trauma patients, and monitoring cardiac rhythm. Given the low acuity of the pediatric prehospital population, other resuscitation skills, particularly airway skills, were rarely used. In fact, during this 6-month study, only 1 child received prehospital intubation, 5 received bag-valve-mask ventilation and 10 had an oral airway inserted. At least in this system, EMS personnel get very little field practice in managing the pediatric airway and most EMS personnel would not have the opportunity to ventilate even a single child in an entire year.

Our results are similar to those of Babl and associates,²³ who studied 555 pediatric ALS transports in an urban setting and reported that 33% of the children had an IV start, 5% had bag-mask ventilation, 3% were intubated and 0.5% received intraosseous access. This equated to a rate per ALS provider (per year) of 3.7 times for IV cannulation, 0.6 times for bag-mask ventilation, 0.3 times for intubation and 0.06 times for intraosseous access. These data suggest that lifesaving pediatric interventions are practised infrequently in the field, and that the same holds true for delivery of ALS medications. Only 19 children received IV medications (10, diazepam; 9, morphine). It is clear that most paramedics would have very little experience in providing IV pain relief to children.

We were surprised to find that 28% of pediatric calls were assessed by EMS but never transported to hospital. Studies of various EMS systems have found that this non-transported population varies widely, from 11%-32% of all pediatric EMS runs.^{1,2,4,6,7,12-14} We found that 24% of parents preferred to transport their child by private vehicle, and 17% decided to observe their child at home. Surprisingly 56% of ACRs had no reason documented for the non-transport, a concerning fact, as the non-transport population is responsible for a substantial proportion of litigation against EMS services.^24,25 Future studies should examine characteristics, reason for non-transport and outcomes of the non-transported pediatric population.

In the subgroup of patients with seizures, we found that the large majority of seizures stopped before EMS arrival. The most common prehospital interventions were blood glucose check, provision of oxygen, cardiac monitoring and establishing an IV line. Only 6% received IV anticonvulsants and very few required airway management or ventilation. This information should be useful to those planning prehospital seizure intervention trials in the future.

Limitations

The 6-month study duration may have led to a seasonal bias; for example, trauma is more common in summer and respiratory and viral illnesses are more common in winter. In addition, this study only examined one geographic setting with relatively short transport times, and results may not be applicable to remote environments or other ambulance systems. We did not assess air transport and as a result may have selectively excluded more critical patients. We cannot determine from these data whether all children receiving a procedure benefited from it, or whether all children who may have benefited from a procedure received it.

These findings have implications for pediatric prehospital education and research. The low rates of pediatric EMS transport and invasive procedure use means that ALS providers may have insufficient experience in pediatric ALS care. Prehospital education programs should address this reality. These findings also tell us that most pediatric transport cases are for trauma, seizures and respiratory distress, and that EMS providers have a major role in treating these concerns. The challenge is to balance the educational requirements of being prepared to manage the rare critically ill or injured child while teaching EMS providers about the most commonly encountered pediatric chief complaints. In addition, the large proportion of non-transported children suggests the need to study this group to ensure that these children have optimal outcomes.

Conclusion

This Canadian pediatric EMS study shows a high rate of Not Transported, and a low rate of Urgent transports and hospital admissions for children. Very few children receive prehospital airway management, ventilation or intravenous medications; consequently EMS personnel may have little opportunity to maintain these pediatric skills in the field.

References

1. Seidel JS, Hornbein M, Yoshiyama K, et al. Emergency medical services and the pediatric patient: Are the needs being met? Pediatrics 1984;73:769-72.
2. Tsai A, Kallsen G. Epidemiology of pediatric prehospital care. Ann Emerg Med 1987;16:284-92.
3. McCaig LF, Ly N. National Hospital Ambulatory Medical Care Survey: 2000 Emergency Department Summary. Advance Data from Vital and Health Statistics; no. 326. Hyattsville (MD): National Center for Health Statistics; 2002.
4. Joyce SM, Brown DE, Nelson EA. Epidemiology of pediatric EMS practice: a multistate analysis. Prehospital Disaster Med 1996;11:180-7.
5. Yamamoto LG, Wiebe RA, Maiava DM, et al. A one-year series of pediatric prehospital care: I. Ambulance runs; II. Prehospital communication; III. Interhospital transport services. Pediatr Emerg Care 1991;7:206-14.
6. Seidel JS, Henderson DP, Ward P, et al. Pediatric prehospital care in urban and rural areas. Pediatrics 1991;88:681-90.
7. Svenson JE, Nypaver M, Calhoun R. Pediatric prehospital care: epidemiology of use in a predominantly rural state. Pediatr Emerg Care 1996;12:173-9.
8. Reisdorff EJ, Howell KA, Saul J, et al. Prehospital interventions in children. Prehosp Emerg Care 1998;2:180-3.
9. Murdock TC, Knapp JF, Dowd MD, et al. Bridging the emergency medical services for children information gap. Arch Pediatr Adolesc Med 1999;153:281-5.
10. Sapien RE, Fullerton L, Olson LM, et al. Disturbing trends: the epidemiology of pediatric emergency medical services use. Acad Emerg Med 1999;6:232-8.
11. Suruda A, Vernon DD, Reading J, et al. Pre-hospital emergency medical services: a population based study of pediatric utilization. Inj Prev 1999;5:294-7.
12. Rosenberg N, Knazik S, Cohen S, et al. Use of Emergency Medical Service transport system in medical patients up to 36 months of age. Pediatr Emerg Care 1998;14:191-3.
13. Brady WJ, Hennes H, Wolf A, et al. Pattern of basic life support ambulance use in an urban pediatric population. Am J Emerg Med 1996;14:250-3.
14. Kost S, Arruda J. Appropriateness of ambulance transportation to a suburban emergency department. Prehosp Emerg Care 1999;3:187-90.
15. Camasso-Richardson K, Wilde JA, Petrack EM. Medically unnecessary pediatric ambulance transports: A medical taxi service? Acad Emerg Med 1997;4:1137-41.
16. Scribano PV, Baker MD, Holmes J, et al. Use of out-of-hospital interventions for the pediatric patient in an urban emergency medical services system. Acad Emerg Med 2000;7:745-50.
17. Sapien RE. Lapidus J. Coors L. Murphy SJ. Prehospital EMS treatment of pediatric asthma and what happens before help arrives? J Asthma 1997;34:477-81.
18. Kost S, Cronan K, Gorelick M, et al. Ambulance use by high-acuity patients in a pediatric ED. Am J Emerg Med 2000;18:679-82.
19. Stiell IG, Wells GA, Spaite DW, et al. The Ontario Prehospital Advanced Life Support (OPALS) Study: rationale and methodology for cardiac arrest patients. Ann Emerg Med 1998;32:180-90.
20. Stiell IG, Wells GA, Field BJ, et al.; OPALS Study Group. Improved out-of-hospital cardiac arrest survival through the inexpensive optimization of an existing defibrillation program (OPALS Study Phase II). JAMA 1999;281:1175-81.
21. Stiell IG, Wells GA, Field B, et al.; OPALS Study Group. Advanced Cardiac Life Support in Out-of-Hospital Cardiac Arrest. N.Engl J Med 2004;351:647-56.
22. Gausche M, Seidel JS. Out-of hospital care of pediatric patients. Pediatr Clin North Am 1999;46:1305-27.
23. Goldberg RJ, Zautcke Jl, Koenigsberg MD, et al. A review of prehospital care litigation in a large metropolitan EMS system. Ann Emerg Med 1990;19:557-61.
24. Soler JM, Montes MF, Egol AB, et al. The 10-year malpractice experience of a large urban EMS system. Ann Emerg Med 1985;14:982-5.
25. Babl FE, Vinci RJ, Bauchner H, et al. Pediatric pre-hospital advanced life support care in an urban setting. Pediatr Emerg Care 2001;17:5-9.