Abstracts for the 2007 NAEMSP Scientific Assembly

Objective. To determine the number of air medical helicopter accidents in the United States during a five-year period beginning January 1, 1997, and ending December 31, 2001. Methods. The National Transportation Safety Board's (NTSB's) Accident Synopses database was accessed to determine the number of accidents involving air medical helicopters during the five-year study period. The NTSB reports for each accident were downloaded. Results. The NTSB records revealed 47 accident files pertaining to air medical helicopters during the five-year study period. These were analyzed for: date of accident, time of accident, air ambulance operator, location of accident, type of aircraft, number of persons, number of fatalities, number of injuries, cause of accident, and other factors the NTSB investigators deemed appropriate. Of the 47 accidents, there were 40 fatalities and 36 injuries. Overall, there were 13 helicopter types involved. The majority of accidents (70%) were attributed to pilot error. The number of accidents increased from a low of 4 in 1997 to a maximum of 12 in both 2000 and 2001. Conclusions. This study has examined 47 U.S. air medical helicopter accidents for a five-year period (1997–2001). There was an increase in the number of accidents during the study period. However, this study is limited by the fact that it presents only raw data and does not reflect the actual incidence of accidents per hours flown. Various factors related to these accidents have been described. These factors should be considered when strategies to improve air medical helicopter safety are developed.     

An Evidence-based Guideline for the Air Medical Transportation of Prehospital Trauma Patients

Abstract

Background. Decisions about the transportation of trauma patients by helicopter are often not well informed by research assessing the risks, benefits, and costs of such transport. Objective. The objective of this evidence-based guideline (EBG) is to recommend a strategy for the selection of prehospital trauma patients who would benefit most from aeromedical transportation. Methods. A multidisciplinary panel was recruited consisting of experts in trauma, EBG development, and emergency medical services (EMS) outcomes research. Representatives of the Federal Interagency Committee on Emergency Medical Services (FICEMS), the National Highway Traffic Safety Administration (NHTSA) (funding agency), and the Children's National Medical Center (investigative team) also contributed to the process. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology to guide question formulation, evidence retrieval, appraisal/synthesis, and formulate recommendations. The process followed the National Evidence-Based Guideline Model Process, which has been approved by the Federal Interagency Committee on EMS and the National EMS Advisory Council. Results. Two strong and three weak recommendations emerged from the process, all supported only by low or very low quality evidence. The panel strongly recommended that the 2011 CDC Guideline for the Field Triage of Injured Patients be used as the initial step in the triage process, and that ground emergency medical services (GEMS) be used for patients not meeting CDC anatomic, physiologic, and situational high-acuity criteria. The panel issued a weak recommendation to use helicopter emergency medical services (HEMS) for higher-acuity patients if there is a time-savings versus GEMS, or if an appropriate hospital is not accessible by GEMS due to systemic/logistical factors. The panel strongly recommended that online medical direction should not be required for activating HEMS. Special consideration was given to the potential need for local adaptation. Conclusions. Systematic and transparent methodology was used to develop an evidence-based guideline for the transportation of prehospital trauma patients. The recommendations provide specific guidance regarding the activation of GEMS and HEMS for patients of varying acuity. Future research is required to strengthen the data and recommendations, define optimal approaches for guideline implementation, and determine the impact of implementation on safety and outcomes including cost.     

The "Vertical Response Time": Barriers to Ambulance Response in an Urban Area

Background: Ambulance response time is typically reported as the time interval from call dispatch to arrival on-scene. However, the often unmeasured "vertical response time" from arrival on-scene to arrival at the patient's side may be substantial, particularly in urban areas with high-rise buildings or other barriers to access.
Objectives: To measure the time interval from arrival on-scene to the patient in a large metropolitan area and to identify barriers to emergency medical services arrival.
Methods: This was a prospective observational study of response times for high-priority call types in the New York City 9-1-1 emergency medical services system. Research assistants riding with paramedics enrolled a convenience sample of calls between 2001 and 2003.
Results: A total of 449 paramedic calls were included, with a median time from call dispatch to arrival on-scene of 5.2 minutes. The median on-scene to patient arrival interval was 2.1 minutes, leading to an actual response interval (dispatch to patient) of 7.6 minutes. The median on-scene to patient interval was 2.8 minutes for residential buildings, 2.7 minutes for office complexes, 1.3 minutes for private homes (less than four stories), and 0.5 minutes for outdoor calls. Overall, for all calls, the on-scene to patient interval accounted for 28% of the actual response interval. When an on-scene escort provided assistance in locating and reaching the patient, the on-scene to patient interval decreased from 2.3 to 1.9 minutes. The total dispatch to patient arrival interval was less than 4 minutes in 8.7%, less than 6 minutes in 28.5%, and less than 8 minutes in 55.7% of calls.
Conclusions: The time from arrival on-scene to the patient's side is an important component of overall response time in large urban areas, particularly in multistory buildings.     

品质圈活动在抢救车管理中的应用

品质圈简称QC小组，是本系统工作人员自愿组成，其目的是通过定期的选题会议和活动，解决和改善工作中的主要问题叫。在临床工作中，每个病区均设有抢救车，我科在提高抢救车质量管理活动中，进行品质圈活动，取得较好的效果，现介绍如下。     

Factors Associated with the Use of Helicopter Inter-facility Transport of Trauma Patients to Tertiary Trauma Centers within an Organized Rural Trauma System

Objective: A review of the literature yielded little information regarding factors associated with the decision to use ground (GEMS) or helicopter (HEMS) emergency medical services for trauma patients transferred inter-facility. Furthermore, studies evaluating the impact of inter-facility transport mode on mortality have reported mixed findings. Since HEMS transport is generally reserved for more severely injured patients, this introduces indication bias, which may explain the mixed findings. Our objective was to identify factors at referring non-tertiary trauma centers (NTC) influencing transport mode decision. Methods: This was a case-control study of trauma patients transferred from a Level III or IV NTC to a tertiary trauma center (TTC) within 24-hours reported to the Oklahoma State Trauma Registry between 2005 and 2012. Multivariable logistic regression was used to determine clinical and non-clinical factors associated with the decision to use HEMS. Results: A total of 7380 patients met the study eligibility. Of these, 2803(38%) were transported inter-facility by HEMS. Penetrating injury, prehospital EMS transport, severe torso injury, hypovolemic shock, and TBI were significant predictors (p<0.05) of HEMS use regardless of distance to a TTC. Association between HEMS use and male gender, Level IV NTC, and local ground EMS resources varied by distance from the TTC. Many HEMS transported patients had minor injuries and normal vital signs. Conclusions: Our results suggest that while distance remains the most influential factor associated with HEMS use, significant differences exist in clinical and non-clinical factors between patients transported by HEMS versus GEMS. To ensure comparability of study groups, studies evaluating outcome differences between HEMS and GEMS should take factors determining transport mode into account. The findings will be used to develop propensity scores to balance baseline risk between GEMS and HEMS patients for use in subsequent studies of outcomes.     

Air Medical Transport of Trauma Patients

This report reviews the current status of air medical transportation of trauma patients. Aspects reviewed include patient care, dispatch, safety, andpossible future directions in air medical patient care.     

Comparison of Crashes Involving Ambulances with Those of Similar-Sized Vehicles

Objective. To describe the characteristics andassociated occupant injuries of motor vehicle collisions (MVCs) involving ambulances as compared with MVCs involving similar-sized vehicles. Methods. Motor vehicle crash data in Pennsylvania from 1997–2001 were analyzed to compare the characteristics of crashes involving ambulances with those involving vehicles of a similar size. Crash demographics (e.g., location of crash, roadway conditions, intersection type) andassociated injuries were examined andcompared using chi-square tests andFisher's exact test. Results. 2,038 ambulance MVCs and23,155 crashes involving similar-sized vehicles were identified. Weather androad surface conditions were similar, but ambulance MVCs occurred with increased frequency on evenings andweekends. Ambulances were more likely to be involved in four-way intersection crashes (43% vs. 23%, p = 0.001), angled collisions (45% vs. 29%, p = 0.001), andcollisions at traffic signals (37% vs. 18%, p = 0.001). More people were involved in ambulance MVCs (p = 0.001), with 84% of ambulance MVCs involving three or more people and33% involving five or more people. Injuries were reported in more ambulance MVCs (76% vs. 61%, p = 0.001). Pedestrian involvement was rare (< 5% in both groups). Conclusion. Ambulance crashes occur more frequently at intersections andtraffic signals andinvolve more people andmore injuries than those of similar-sized vehicles.     

Flying Home

In the rapidly progressing field of critical care, the diverse delivery of such care seems to be reaching new "heights." In particular, aeromedical transport of critically ill patients involves detailed preparation for the worst possibilities but with expectations for the best outcomes. The following case is presented as testimony to the challenges of critical care transport.     

U TILIZATION AND I MPACT OF A MBULANCE D IVERSION AT THE C OMMUNITY L EVEL

Objective. To evaluate the utilization and impact of ambulance diversion in the metropolitan area of Syracuse, New York. Methods. This was a retrospective review of the ambulance diversion system operated by the hospitals of Syracuse, New York. This system allows each emergency department to divert incoming ambulances during periods of extreme overcrowding. Data collected included numbers of hours on ambulance diversion by hospital, numbers of hours when all four hospitals were on diversion simultaneously, and numbers of ambulances received while the hospitals were on and off diversion. Results. For three of the five years evaluated, ambulance diversion hours were most numerous during the period between January and March. For the most recent year studied (2000), ambulance diversion hours did not decline after the first quarter. During periods of diversion, hospital emergency departments received 30%–50% fewer ambulances than they did while open. Conclusion. This study demonstrated that, in Syracuse, New York, ambulance diversion was once a seasonal phenomenon, but is increasingly occurring throughout the year because of staff and resource limitations. It also demonstrated that ambulance diversion can be employed to reduce numbers of incoming transports.     

Pediatric Blunt Neck Trauma Causing Esophageal and Complete Tracheal Transection

Background: Blunt injuries to the cervical trachea remain rare but present unique and challenging clinical scenarios for prehospital providers. These injuries depend on prehospital providers either definitively securing the injured airway or bridging the patient to a treatment facility that can mobilize the necessary resources. Case Summary: The case presented here involves a clothesline injury to a pediatric patient that resulted in complete tracheal transection and partial esophageal transection. Ground and air prehospital providers utilized a stepwise approach to this airway injury and achieved a favorable outcome. The patient was serendipitously intubated through a blind nasal approach that entered the proximal esophagus, exited through the tear and entered the distal trachea. Discussion: There is a paucity of literature describing the successful management of these devastating injuries. While some authors have advocated for early flexible fiberoptic intubation or proceeding directly to tracheostomy, these techniques are not available in the prehospital environment. This case also highlights the inherent issues with proceeding to cricothyroidotomy in patients with tracheal trauma and should give all providers pause before considering this management technique. Conclusion: Ultimately, a systematic approach to all airways will ensure that prehospital providers are best prepared for even the most challenging scenarios.     

The effect of etomidate on airway management practices of an air medical transport service

Objective

The authors studied the effect of introducing etomidate on the airway management practices of their air transport crew and specifically considered the need for paralytic agents during rapid-sequence intubation.

Methods

A prospective observational review of the transport records for all patients aged greater than 10 years who required intubation transported by the air medical crew before (PRE) and after (POST) the introduction of etomidate into the authors' rapid-sequence induction protocol was conducted. Data were collected, including the method of intubation, indications for intubation, and complications from the procedure. The following outcomes were measured: the method used for intubation (nasotracheal or orotracheal), oral intubation success rate, number of attempts for oral intubation, need for paralytic agents, and complications with the procedure.

Results

Comparing the PRE and POST periods, nasotracheal intubation was performed in 27 of 70 (38.6%) versus 33 of 71 (46.4%; p = 0.237997). The overall success rate for intubation in the PRE period was 67 of 70 (95.7%), with 95.3% of orotracheal intubations being successful. In the POST period, the overall success rate was 65 of 71 (91.5%), with 94.7% of orotracheal intubations being successful. Complication rates were similar between the groups. Etomidate reduced the use of paralytic agents from 46 of 62 (74.6%) of patients receiving midazolam to 10 of 22 (45.5%) intubated with etomidate (p = 0.02).

Conclusions

Etomidate did not appear to have an impact on the selection of intubation methods by the air medical transport crew. Etomidate significantly reduced the need for administration of paralytic agents used in an RSI.     

Comparison of etomidate and midazolam for prehospital Rapid-sequence intubation

Objective

This study compares etomidate with midazolam for prehospital rapid-sequence intubation (RSI).

Methods

The authors conducted a retrospective review of consecutive intubations at a university-based air medical program from January 1995 to December 2000. Exclusion criteria were patients not undergoing RSI, age <15 years, and incomplete chart data. Outcome measures included intubation success, incidence of hypotension, and percentage of change in heart rate (HR) and systolic blood pressure (SBP).

Results

The intubation success rate was 110 out of 112 (98%) with etomidate, and 96 out of 97 (99%) with midazolam. Mean ages, patient gender distributions, and initial SBPs and HRs did not differ between the two groups. The mean dose of etomidate was 24 mg, the mean percentage of change in HR was −1% (95% confidence interval [CI], −6 to 4), and the mean percentage of change in SBP was 2% (95% CI, −3 to 7). The mean dose of midazolam was 3.5 mg, the mean percentage of change in HR was 1% (95% CI, −5 to 7), and the mean percentage change in SBP was 3% (95% CI, −3 to 9). The number of hypotensive episodes with etomidate (7 out of 74) compared with midazolam (3 out of 56) did not differ significantly (Fisher's exact test, p = 0.51).

Conclusion

Intubation success rate was very high with both etomidate (98%) and midazolam (99%). There was no statistically significant mean percentage of change in SBP or HR with either agent. The authors found a low incidence of hypotension with both agents, although the mean dose of midazolam used was considerably less than typically recommended for induction.     

Neighborhood Poverty and 9-1-1 Ambulance Response Time

Background: Are 9-1-1 ambulances relatively late to poorer neighborhoods? Studies suggesting so often rely on weak measures of neighborhood (e.g., postal zip code), limit the analysis to particular ambulance encounters (e.g., cardiac arrest responses), and do little to account for variations in dispatch priority or intervention severity. Methods: We merged EMS ambulance contact records in a single California county (n = 87,554) with tract-level data from the American Community Survey (n = 300). After calculating tract-level median ambulance response time (MART), we used ordinary least squares (OLS) regression to estimate a conditional average relationship between neighborhood poverty and MART and quantile regression to condition this relationship on 25th, 50th, and 75th percentiles of MART. We also specified each of these outcomes by five dispatch priorities and by three intervention severities. For each model, we estimated the associated changes in MART per 10 percentage point increase in tract-level poverty while adjusting for emergency department proximity, population density, and population size. Results: Our study produced three major findings. First, most of our tests suggested tract-level poverty was negatively associated with MART. Our baseline OLS model estimates that a 10 percentage point increase in tract-level poverty is associated with almost a 24 s decrease in MART (?23.55 s, 95% confidence interval [CI] ?33.13 to ?13.98). Results from our quantile regression models provided further evidence for this association. Second, we did not find evidence that ambulances are relatively late to poorer neighborhoods when specifying MART by dispatch priority. Third, we were also unable to identify a positive association between tract-level poverty and MART when we specified our outcomes by three intervention severities. Across each of our 36 models, tract-level poverty was either not significantly associated with MART or was negatively associated with MART by a magnitude smaller than a full minute per estimated 10 percentage point increase in poverty concentration. Conclusion: Our study challenges the commonly held assumption that ambulances are later to poor neighborhoods. We scrutinize our findings before cautiously considering their relevance for ambulance response time research and for ongoing conversations on the relationship between neighborhood poverty and prehospital care.     

空间站任务阶段航天员的医疗救护保障北大核心CSCD

目的回顾总结载人航天史上曾经发生的主要问题以及我国自2003年神舟五号首次载人航天任务以来主着陆场航天员医疗保障的经验,重点分析自神舟十二号开始的空间站建造期间的技术状态和返回特点,制定有针对性的伤病救治预案,确保航天员安全。方法总结国外航天史上航天员发生意外伤害的教训,尤其是空间站阶段,结合我国载人航天的航天员医疗保障经验,针对空间站任务飞船在轨时间长、主着陆场调整的任务特点,提出系列的组织、预案以及救治方案。结果在原有舱前急救、直升机ICU综合救护平台的基础上,进一步优化了急救程序,制定了不同复杂地形情况下的救治预案及航天员的快速救治和后送原则。结论空间站任务医疗救护的综合救援方案、直升机救护平台的构建以及组织实施,可以保障空间站任务航天员各种情况返回的有效救治。     

Feasibility of Paramedic Performed Prehospital Lung Ultrasound in Medical Patients with Respiratory Distress

Objective: Prehospital ultrasound is not yet widely implemented. Most studies report on convenience samples and trauma patients, often by prehospital physicians or critical care clinicians. We assessed the feasibility of paramedic performed prehospital lung ultrasound in medical patients with respiratory distress. Methods: Paramedics at 2 ambulance stations in the city of Pittsburgh, Pennsylvania, USA underwent a 2-hour training session in prehospital lung ultrasound using the SonoSite iViz, a handheld ultrasound device. Emergency medical services (EMS) command center (EMS-CC) physicians were instructed in the interpretation of lung ultrasound images. Paramedics enrolled patients presenting with signs and symptoms of respiratory distress over a 3-month period. The ultrasound exam included anterior and lateral views from both sides of the chest. Images were transmitted wirelessly using a mobile hotspot device and uploaded into an online image archiving system. Images were interpreted remotely by the EMS-CC physicians, and 2 expert sonographers provided an overread. We assessed agreement between EMS-CC physicians and experts, as well as between chart-review derived ED diagnosis and both EMS-CC physician and expert interpretation. We defined four a priori hypotheses that would need to be met for the intervention to be considered “feasible.” Results: A total of 34 of 78 (43.6%) eligible patients had an ultrasound exam completed. Image transmission was successful in 25 (73.5%) of cases where ultrasound was performed. The primary reason for not enrolling an otherwise eligible patient was equipment failure (25.0%), followed by patient acuity and patient refusal (18.2% each). A total of 20 (58.8%) completed scans were deemed uninterpretable upon expert review. Agreement between EMS physicians and experts was poor. Agreement between EMS-CC physicians and ED diagnosis, as well as between experts and ED diagnosis, was fair. The predetermined thresholds for feasibility were not met. Conclusions: Paramedic performed prehospital lung ultrasound for patients with respiratory distress and remote interpretation by EMS physicians did not meet the predetermined thresholds to be considered “feasible” in a real-world environment with currently available technologies. This study identified important barriers to the implementation of prehospital lung ultrasound, which should be addressed in future studies.     

Oxygen alert cards and controlled oxygen: preventing emergency admissions at risk of hypercapnic acidosis receiving high inspired oxygen concentrations in ambulances and A&E departments

Background

Appropriate resuscitation of hypoxic patients is fundamental in emergency admissions. To achieve this, it is standard practice of ambulance staff to administer high concentrations of oxygen to patients who may be in respiratory distress. A proportion of patients with chronic respiratory disease will become hypercapnic on this.

Objectives and methods

A scheme was agreed between the authors'' hospital and the local ambulance service, whereby patients with a history of previous hypercapnic acidosis with a Pao₂ >10.0 kPa—indicating that oxygen may have worsened the hypercapnia—are issued with “O₂ Alert” cards and a 24% Venturi mask. The patients are instructed to show these to ambulance and A&E staff who will then use the mask to avoid excessive oxygenation. The scheme was launched in 2001 and this paper present the results of an audit of the scheme in 2004.

Results

A total of 18 patients were issued with cards, and 14 were readmitted on 69 occasions. Sufficient documentation for auditing purposes was available for 52 of the 69 episodes. Of these audited admissions, 63% were managed in the ambulance, in line with card‐holder protocol. This figure rose to 94% in the accident and emergency department.

Conclusion

These data support the usability of such a scheme to prevent iatrogenic hypercapnia in emergency admissions.     

Trauma bypass in south-eastern Sydney: an 8-year review

Objective: The New South Wales (NSW) Health Department and the Ambulance Service of NSW introduced a trauma bypass system in Sydney on 29 March 1992. This study aims to review the outcomes of trauma bypass patients brought to St George Hospital, a major trauma service in south‐eastern Sydney, and to assess the performance of the current prehospital trauma triage protocol. Methods: The St George Hospital Department of Trauma Services prospectively collected data on all trauma bypass patients for the 8‐year period from 29 March 1992 to 29 March 2000. Results: A total of 1990 patients were brought to hospital on trauma bypass. The average age was 32 years, 70% were men and 66% were from road traffic accidents. The positive predictive value of the prehospital triage tool for serious injury (Injury Severity Score [ISS] > 15) was 18.6% (95% CI 16.9–20.4). This is well below the benchmark previously established by the NSW Health Department Trauma System Advisory Committee. For all trauma bypass patients, 33.8% (95% CI 31.7–35.9) were discharged home from the ED. The overall death rate was 2.5% (95% CI 1.9–3.3). Conclusions: According to the proposed benchmark, current prehospital trauma triage guidelines are underperforming. This suggests that a review of the benchmarks of current local trauma systems and of the trauma triage tool is required.