The use of capnography in the air medical environment.

We can count on two things when we receive a call as part of an air medical transport team--the patient is in critical condition, and time is of the essence. Whether the patient has experienced trauma from a motor vehicle crash, has fallen, or has suffered an insult as a consequence of poor health, our technique, skill, and judgment are tested constantly. Fortunately, we have equipment at our disposal to make our job easier. One of the more difficult aspects and responsibilities of air medical transport teams is placement of an endotracheal tube (ET). Along with the techniques used for successful endotracheal intubation (ETI), available technology can maximize patients' ventilatory status using an instrument that detects expired carbon dioxide (CO(2)) levels.

Free fluid on abdominal computed tomography without solid organ injury after blunt abdominal injury does not mandate celiotomy.

BACKGROUND: Mandatory celiotomy has been proposed for all patients with unexplained free fluid on abdominal computed tomography (CT) scanning after blunt abdominal injury. This recommendation has been based upon retrospective data and concerns over the potential morbidity from the late diagnosis of blunt intestinal injury. This study examined the rate of intestinal injury in patients with free fluid on abdominal CT after blunt abdominal trauma. METHODS: This study was a multicenter prospective series of all patients with blunt abdominal trauma admitted to four level I trauma centers over 22 months. Data were collected concurrently at the time of patient enrollment and included demographics, injury severity score, findings on CT scan, and presence or absence of blunt intestinal injury. This database was specifically queried for those patients who had free fluid without solid organ injury. RESULTS: In all, 2,299 patients were evaluated. Free fluid was present in 265. Of these, 90 patients had isolated free fluid with only 7 having a blunt intestinal injury. Conversely, 91% of patients with free fluid did not. All patients with free fluid were observed for a mean of 8 days (95% confidence interval 6.1 to 10.4, range 1 to 131). There were no missed injuries. CONCLUSIONS: Free fluid on abdominal CT scan does not mandate celiotomy. Serial observation with the possible use of other adjunctive tests is recommended.

Early trauma polymorphonuclear neutrophil responses to chemokines are associated with development of sepsis, pneumonia, and organ failure.

OBJECTIVES: The modulation of polymorphonuclear neutrophil (PMN) function by injury is unpredictable, and can predispose either to hyperimmune states (adult respiratory distress syndrome [ARDS], multiple organ failure) or to immune dysfunction, infection, and sepsis. Such outcomes have been related to excess production of the CXC chemokine interleukin (IL)-8, but PMN responses to IL-8 are mediated by both the relatively stable and IL-8 specific CXC receptor 1 (CXCR1) and the labile, promiscuous CXCR2. We hypothesized that progression to septic and multiple organ failure outcomes could be related to early differences in PMN CXC receptor status. METHODS: PMNs were isolated 12 +/- 3 hours after injury from 15 major trauma patients (Injury Severity Score of 34 +/- 2, 11 men and 4 women, age 36 +/- 4 years) who survived at least 7 days. Volunteer normal PMNs (n = 6 donors) were studied for comparison. Cells were stimulated either with the CXCR2 specific agent growth-related oncogene-alpha, or with IL-8, which stimulates CXCR1 and CXRR2. Receptor response was assessed as the mobilization of cell calcium. The development of ARDS, sepsis, and pneumonia was assessed according to standardized criteria. Day 1 receptor activity in the clinical groups was then compared by analysis of variance with Tukey's or t tests as appropriate. RESULTS: In patients that were otherwise comparable, CXCR2 responses were markedly diminished in the PMNs of patients who went on to sepsis and pneumonia, but were elevated in PMNs from the patients who went on to ARDS. CXCR1 responses were modestly lower in trauma patients than volunteers, but showed no significant variations among the various clinical outcome groups. CONCLUSION: The activity of PMN CXCR2 receptors soon after injury may be reflected in the later clinical sequelae of PMN activity. High CXCR2 activity may correlate with PMN hyperfunction and outcomes such as ARDS, whereas the loss of CXCR2 function in inflammatory environments may impair PMN functions in a manner that predisposes to pneumonia or sepsis. Early responses of PMN CXC receptors to injury may influence the clinical course of trauma patients.

A national survey of air medical infectious disease control practices.

INTRODUCTION: Caring for an infectious patient in the air medical environment presents a special challenge to all air crew members (ACMs) involved. The purpose of this study was to survey the infectious disease control practices of air medical programs (AMPs) that are members of the Association of Air Medical Services. METHODS: A structured telephone survey was designed to gather data. Using one interviewer (an undergraduate student) with no knowledge of the study's goal minimized experimental bias. AMPs from 151 geographically selected areas were called between June and August 1996. Only the programs' chief flight nurses (CFNs) were targeted as respondents. RESULTS: The response rate was 91% (138 of 151). Although no program refused to participate, 13 CFNs were unavailable to be interviewed. Mission profile was 32% scene and 68% interhospital with an annual average of 950 patient transports per program. Transport type was 61% rotor-wing aircraft, 17% fixed-wing, and 22% both. Flight physicals for ACMs were required by 57% of the AMPs. Pre-employment screenings for rubella, tuberculosis (TB), and varicella were noted. Interestingly, 17% of the AMPs reported pre-employment HIV testing. Immunization was mandated by 57% of AMPs, including hepatitis B virus, measles, rubella, and tetanus. Nine percent of the respondents refused to accept a transport with specific contagious conditions, primarily TB. A formal decontamination policy was in effect at 88% of the AMPs, and OSHA-approved filter masks were available at 70%. Pathogen exposure reporting was required by 97%. CONCLUSION: A current, comprehensive infection control program, continuing education, and 100% compliance with standard precautions will help reduce the possibility of accidental exposures. These strategies to reduce transmission also can be extended during training sessions to the prehospital and hospital personnel with whom the air medical program serves.

Emergency department discharge of patients with a negative cranial computed tomography scan after minimal head injury.

OBJECTIVE: To determine the negative predictive value of cranial computed tomography (CT) scanning in a prospective series of patients and whether hospital admission for observation is mandatory after a negative diagnostic evaluation after minimal head injury (MHI). SUMMARY BACKGROUND DATA: Hospital admission for observation is a current standard of practice for patients who have sustained MHI, despite having undergone diagnostic studies that exclude the presence of an intracranial injury. The reasons for this practice are multifactorial and include the perceived false-negative rate of all standard diagnostic tests, the belief that admission will allow prompt diagnosis of occult injuries, and medicolegal considerations about the risk of early discharge. METHODS: In a prospective, multiinstitutional study during a 22-month period at four level I trauma centers, all patients with MHI were evaluated using the following protocol: a standardized physical and neurologic examination in the emergency department, cranial CT scanning, and then admission for observation. MHI was defined as either a documented loss of consciousness or evidence of posttraumatic amnesia and an emergency department Glasgow Coma Scale score of 14 or 15. Outcomes were measured at 20 hours and at discharge and included clinical deterioration, need for craniotomy, and death. RESULTS: Two thousand one hundred fifty-two consecutive patients fulfilled the study protocol. The CT was interpreted as negative for intracranial injury in 1,788, positive in 217, and equivocal in 119. Five patients with CT scans initially interpreted as negative required intervention. There was one craniotomy in a patient whose CT scan was initially interpreted as negative. This patient had facial fractures that required surgical intervention and elevation of depressed intracranial fracture fragments. The negative predictive power of a cranial CT scan based on the preliminary reading of the CT scan and defined by the subsequent need for neurosurgical intervention in the population fully satisfying the protocol was 99.70%. CONCLUSIONS: Patients with a cranial CT scan, obtained on a helical CT scanner, that shows no intracerebral injury and who do not have other body system injuries or a persistence of any neurologic finding can be safely discharged from the emergency department without a period of either inpatient or outpatient observation. Implementation of this practice could result in a potential decrease of more than 500,000 hospital admissions annually.

The utility of venous lactate to triage injured patients in the trauma center.

BACKGROUND: Field triage criteria for trauma patients results in over-triage rates of 30% to 50% to achieve under-triage rates of 10%. This large number of patients may stress trauma center resources. Elevated arterial lactate (ALAC) levels have been shown to be a marker of serious injury but the need for arterial sampling limits the utility of the determination. The goal of this study was: 1) to determine the correlation between venous lactate (VLAC) and ALAC; 2) to determine whether VLAC could identify those patients with serious injuries; and 3) to compare an elevated VLAC level against standard triage criteria (STC) in their ability to identify major injury. STUDY DESIGN: Arterial and venous samples for blood gas and lactate analyses were obtained in 375 patients within 10 minutes of patient arrival to the trauma center. Arterial and venous samples were drawn within 2 minutes of each other, placed on ice, and analyzed within 10 minutes of sampling. The location of sampling was left to physician discretion. Data collected included injury mechanism, demographics, admission vital signs, emergency department disposition, length of stay, and injury severity scores (ISS). Admission to the ICU, need for emergency operation, length of stay, and death were noted. Emergency medical service staff were queried to determine which standard triage criteria (STC) were fulfilled. RESULTS: The mean ALAC was 3.11 mmol/L (SD 3.45, 95% confidence interval [CI] 2.67 to 3.55) and mean VLAC was 3.43 mmol/L (SD 3.41, 95% CI 2.96 to 3.90). There was no significant difference between ALAC and VLAC. The correlation between ALAC and VLAC was 0.94 (95% CI 0.94 to 0.96, p = 0.0001). An elevated VLAC predicted moderate to severe injury and there was a significant association between an increased lactate and maximum Abbreviated Injury Score (AIS) of 4 and 5 (ANOVA, F = 8.26, p < 0.001). Patients with VLAC > or =2 mmol/L had significantly increased relative risks of ISS > or = 13, death, admission to the ICU, and length of stay > 2 days. In comparison with STC, a VLAC > or = 2 mmol/L decreased undertriage in patients with ISS > or = 13 by one half (11% versus 24%) for patients with ISS > or = 13 and decreased over-triage by 28% (46% versus 64%). These data were most pronounced for patients injured in motor vehicle collisions. CONCLUSIONS: VLAC is an excellent approximation for ALAC. A VLAC > or = 2 mmol/L appears to predict an ISS > or = 13, the need for ICU resources, and prolonged hospital stays. VLAC was significantly better than STC in all patients and was most useful in victims of blunt trauma, especially motor vehicle collisions.

Taking care of the "good guys:" a trauma center-based model of medical support for tactical law enforcement.

The potential need for rapid medical intervention and access to a trauma center after major injury is crucial to the safety and success of SWAT team operations. This manuscript describes the genesis and development of a unique model for which advanced medical care is rendered by trained health care professionals within a regional trauma system in the support of a SWAT team. The model was developed jointly by the Newark, New Jersey, Division of the Federal Bureau of Investigation and The New Jersey Trauma Center-University Hospital, an academic, urban Level I trauma center. After the signing of a Memorandum of Understanding between the two agencies in 1995, the program became operational. The medical team is composed of physicians, nurses, and paramedics. Since inception, the medical team has provided medical support for 33 tactical missions and 99 training days. Ten patients were treated: 7 agents (syncope, fractured foot, blunt head/neck trauma, lacerations), 2 bystanders (chest pain, asthma), and 1 suspect (chest pain). The advantages of the Newark model in contrast to other programs of tactical medical support, are the operational activities of the team and the cost of the program was outlined.

Think before you act: a national survey of interhospital transfer policies and practices.

INTRODUCTION: As health care evolves, air medical program (AMP) interhospital transfers will come under increasing scrutiny. The object of this study was to evaluate various components of the interhospital transfer policies of AMPs across the country. METHODS: A structured telephone interview of the chief flight nurse (CFN) or administrator of 90 geographically selected AMPs was conducted by a college-educated research assistant using a scripted questionnaire. RESULTS: Seventy-seven (86%) of the AMPs contacted agreed to answer the questionnaire. CFN or administrator unavailability was the reason for nonresponse. The mean number of flights performed per year was 1046: 29% scence and 71% interhospital missions. Mission profile ranged from fixed-wing (19), rotor-wing (45), and both (13). Forty-five percent of respondents require prior administrative approval and 31% require prior medical approval before accepting an interhospital mission. Financial approval or long distance transport was the most common reason for requiring approval. Ninety-four percent of programs transferred patients to facilities other than the AMPs' host hospital; two-thirds of these programs required medical (30%) or administrative (35%) authorization before accepting missions. CONCLUSION: This survey indicates that most AMPs use some form of screening mechanism for interhospital flight requests. With managed care requiring health care delivery systems to examine the use of resources, AMPs should continue to stay ahead of trends that affect the industry.

Validation of a hand-held lactate device in determination of blood lactate in critically injured patients.

OBJECTIVES: Admission blood lactate is an accurate predictor of injury severity and mortality in trauma patients. The purpose of this study was to evaluate a portable lactate analyzer in a clinical setting by patient care staff. DESIGN: A prospective, single-operator control solution and patient sample study, using two test devices and a reference device. SETTING: An urban Level I trauma center. PATIENTS: A convenience sample of 47 trauma patients. INTERVENTIONS: Intra-assay precision was demonstrated by performance of consecutive analyses of two lactate control solutions (high and low lactate control concentrations) by medical students and physicians. Split sample, simultaneous testing of the portable lactate analyzer was then performed on 66 whole blood specimens from a convenience sample of 47 trauma patients admitted to an urban Level 1 trauma center over 4 mos. Samples were tested simultaneously tested on two portable lactate analyzers and a reference instrument. MEASUREMENTS AND MAIN RESULTS: Acceptable intra-assay precision was achieved. Regression analysis for two test instruments demonstrated a slope of 0.920, an intercept of 0.323, an r2 of .982, and an SEM of 0.496. Regression analysis for test instrument "A" vs. the reference instrument showed a slope of 0.861, an intercept of 0.209, an r2 of .977, and an SEM of 0.598. Regression analysis for test instrument "B" vs. the reference instrument demonstrated a slope of 0.929, an intercept of -0.095, an r2 of .983, and an SEM of 0.506. CONCLUSIONS: Good correlation with a low SEM was obtained over a wide range of clinically relevant lactate values. Use of point of care lactate analysis will decrease analytic time, making an important diagnostic parameter immediately available in the critical care setting.

Admission or observation is not necessary after a negative abdominal computed tomographic scan in patients with suspected blunt abdominal trauma: results of a prospective, multi-institutional trial.

OBJECTIVES: Hospitalization for observation is the current standard of practice for patients who have sustained blunt abdominal trauma and who do not require emergent operation, despite having undergone diagnostic studies that exclude the presence of an intra-abdominal injury. The reasons for this practice are multifactorial and include the perceived false-negative rate of all standard diagnostic tests, the belief that hospitalization will allow for the prompt diagnosis of occult injuries, and medicolegal considerations about the risk of early discharge. The focus of this study was to determine whether hospitalization for observation is necessary after a negative diagnostic evaluation after blunt abdominal trauma, to determine the negative predictive value of abdominal computed tomographic (CT) scanning in a prospective series of patients, and to identify which patients can be safely released from the emergency department without observation or hospitalization after blunt abdominal trauma. METHODS: In a prospective, multi-institutional study over 22 months at four Level I trauma centers, all patients with blunt abdominal trauma suspected by either physical examination or mechanism of injury were evaluated using the following protocol: physical examination in the emergency department, followed by abdominal CT scanning, followed by hospitalization for observation. The standardized physical examination was repeated between 4 and 8 hours. Outcomes were measured at 20 hours and at discharge and included clinical deterioration, the need for celiotomy, and mortality. Other data collected included demographics, mechanism of injury, and findings on physical examination and abdominal CT scanning. RESULTS: Three thousand eight hundred twenty-two consecutive patients with suspected abdominal trauma presented to the four trauma centers. Two thousand seven hundred seventy-four of these met study eligibility criteria and were prospectively enrolled. Of these, 2299 fulfilled the entire study protocol. CT scan was negative in 1,809 patients, positive for organ injury or abdominal fluid in 389 patients, and nondiagnostic in 78 patients. Abdominal tenderness or bruising was present in 1,380 patients (61%), but only 22% had a positive CT scan. Nineteen percent of patients with a positive CT scan had no tenderness. Computed tomography detected 22 of the 25 blunt intestinal injuries in this series. Free intraperitoneal fluid without solid visceral injury was present in 90 patients, and but only 7 patients had intestinal injuries. There were nine celiotomies in patients whose CT scan was initially interpreted as negative: six were therapeutic (intestine in three, bladder in one, kidney in one, and diaphragm in one), two were nontherapeutic, and one was negative. The negative predictive power of an abdominal CT scan based on the preliminary reading and as defined by the subsequent need for a celiotomy in the population fully satisfying the protocol was 99.63% (lower 95 and 99% confidence bounds of 99.31 and 99.16%, respectively). CONCLUSION: These data indicate that abdominal tenderness is not predictive of an abdominal injury and that patients with a negative CT scan after suspected blunt abdominal trauma do not benefit from hospital admission and prolonged observation.

Suppression of natural killer cell activity in patients with fracture/soft tissue injury.

BACKGROUND: Natural killer cells (NKCs) participate in "innate" cell-mediated immunity. Fracture/soft tissue injuries are cytokine rich and may influence cell-mediated immunity. OBJECTIVE: To study the effects of fracture cytokines on NKC function. DESIGN: A case-control study. SETTING: A level I trauma center and laboratory in a university medical center. PARTICIPANTS: Patients requiring open fracture fixation and healthy volunteers. INTERVENTIONS: Fracture supernatants and peripheral plasma were collected during open fracture fixation. Volunteer mononuclear cells were used as effector (NKC) sources. Mononuclear cells were preincubated with fracture supernatants, paired peripheral plasma, or normal plasma under various conditions. MAIN OUTCOME MEASURES: Natural killer cell lysis of K562 target cells was assessed by chromium 51 release. RESULTS: Fracture supernatants suppressed NKC function more rapidly than peripheral plasma. Fracture supernatants from 1 to 4 days after injury were most suppressive. Inactivation of complement and reactive oxygen species failed to restore lysis. Neutralizing antibodies to interleukin 4 and interleukin 10 further suppressed lysis. Antibodies to transforming growth factor beta1 failed to restore lysis. The addition of interferon gamma did not restore lysis but the addition of interleukin 12 did. CONCLUSIONS: Fracture supernatants and peripheral plasma from patients with fractures suppress NKCs. The responsible mediators may be concentrated in fracture/soft tissue injuries. Responses to manipulation of the cytokine environment suggest that fracture cytokines may impair cooperation between NKCs and accessory cells.

Requiring on-line medical command for helicopter request prolongs computer-modeled transport time to the nearest trauma center.

INTRODUCTION: Rapid transport from scene to closest trauma center requires optimal use of public safety first responder (FR), basic life support (BLS), advanced life support (ALS), and transport resources (ground or air). In some parts of this regional emergency medical services (EMS) system, on-scene ALS requires contact with on-line medical command (OLMC) to obtain authorization for air medical helicopter (AMH) dispatch, because some EMS medical directors believe that this may decrease overutilization of AMH services. HYPOTHESIS: The hypothesis of this study was that requiring prior OLMC for AMH dispatch prolongs mean time to a trauma center versus either FR or BLS request for AMH. METHODS: Computer mapping programs were used to model the most rapid driving time to the closest trauma center from 167 actual AMH responses to the scene of a motor vehicle accident. In an OLMC-ALS model, only OLMC-ALS can request an AMH. In a BLS model, BLS units arrive on the scene and the crew requests simultaneous dispatch of an ALS response and an AMH. In the FR model, on arrival at the scene, a FR requests simultaneous dispatch of a BLS unit, an ALS unit, and an AMH. RESULTS: The OLMC-ALS model resulted in a longer mean value for time to trauma center by an AMH than did the computer model for all ground transport settings. The FR model yielded a shorter mean time for AMH compared with the mean values for time to trauma center for all settings. Differences in mean values for time in urban settings were small (ground: 42 minutes, air: 36 minutes), whereas those for the suburban (ground: 52 minutes, air: 41 minutes), and those for rural (ground: 69 minutes, air: 47 minutes) were significant clinically. For the BLS model, these differences persisted, but were significant clinically only in the rural setting (ground: 68 minutes, air: 53 minutes). CONCLUSIONS: Optimal use of AMH requires balancing the need for early helicopter dispatch to fully exploit its speed advantage with the disadvantage of expensive overutilization. This computer model indicates that the best person to request AMH varies by venue: in urban settings, the OLMC physician should request AMH dispatch; in suburban venues, BLS should request AMH dispatch; and in rural venues, FRs should request AMH dispatch.

Precision, accuracy, and managed care implications of a hand-held whole blood analyzer in the prehospital setting.

Hand-held portable clinical analyzers permit the rapid measurement of whole blood electrolytes, glucose, blood urea nitrogen (BUN) and hematocrit. Knowledge of these values in the field might aid radio telemetry emergency department physicians in the field treatment and triage of patients. The purpose of this study was determine if the analyzer could function in the hostile prehospital environment. In phase 1, analyses of control electrolyte (n = 30) and hematocrit (n = 28) solutions were performed in a moving ambulance by paramedics to determine precision performance. The F-statistic was used to compare variances against reference values and no significant differences were found. In phase 2, prospective split-sample testing of 57 whole blood samples drawn in the field were analyzed on 2 machines by paramedics in a moving ambulance, and then again within 10 minutes of arrival at the receiving hospital emergency department. Regression analysis between ambulance and emergency department venues revealed high correlation (r) values: sodium (Na)+ (0.93), potassium (K)+ (0.99), chloride (Cl)- (0.89), BUN (0.99), glucose (0.99), hematocrit (0.95), and hemoglobin (0.92). A hand-held whole blood analyzer can be reliably used in the field to obtain blood chemistry and hematocrit values. There was excellent correlation between field and hospital emergency department values. Clinical pathologists extend their oversight and consider encouraging emergency physicians to obtain field blood chemistry values in research studies aimed at improving medical treatment and patient triage in the prehospital setting. We speculate that these results might be important to managed care groups because knowledge of blood chemistry values in the field might provide physicians with objective, criteria-based data on which to triage patients to the emergency department, to an ambulatory care setting, or to a community health center with attendant cost savings.

The impact of multiple patient transport on patient care in helicopter emergency medical services.

INTRODUCTION: Many helicopter emergency medical services can transport either one (singles) or two (doubles) patients. The purpose of this study was to investigate whether the additional patient in the doubles flight had an adverse impact on patient care because of the deceased provider-to-patient ratio. SETTING: Patients were flown by a Level 1 trauma center-based helicopter emergency medical service staffed by a nurse and paramedic. METHOD. A retrospective record and trauma registry review comparing 124 randomly selected scene trauma singles frequency-matched to 100 doubles (1/89 through 6/92) was performed. Data collected included patient demographics, Injury Severity Score, Glasgow Coma Scale, Revised Trauma Score, mechanism of injury, scene time, and ground ALS and helicopter emergency medical services procedures performed. RESULTS: Doubles accounted for 6.5% of all on-scene helicopter emergency medical service trauma patient transports. Paired comparison of Glasgow Coma Scale, Revised Trauma Score, and Injury Severity Score revealed that only one of the doubles patients had a field Glasgow Coma Scale as low, or a Injury Severity Score as high as the average singles. Revised trauma scores were equivalent. Although more procedures were performed during doubles missions, no procedures were performed in most singles missions (58%) and a substantial minority of doubles missions (41%). No differences were found between the groups in change in Glasgow Coma Scale during flight. CONCLUSION: Only of the two patients during doubles missions was as severely injured as the average patient in a singles transport. The decreased ratio of helicopter emergency medical service crew to patients in doubles missions does not jeopardize patient care because few procedures were performed during either singles or doubles missions.

Out-of-hospital use of a pulse oximeter to determine systolic blood pressures.

STUDY OBJECTIVE: Blood pressure (BP) in the out-of-hospital setting is one of the most important diagnostic tools used by emergency medical services (EMS) providers. Conventional methods of palpation and auscultation can be time consuming, and the measurements often are inaccurate because of the adverse working conditions encountered. Pulse oximetry waveform systolic blood pressure (POWSBP) measurement has been used successfully in emergency departments to monitor BP. The objective of this study was to compare the accuracy of field POWSBP measurements obtained by noninvasive electronic BP measurement (NIBPM), auscultation, and palpation in the out-of-hospital environment. DESIGN: Blood pressure measurements used for this study were obtained by POWSBP, NIBPM (PROPAQ model 102; Protocol Systems, Beaverton, Oregon USA), auscultation, and palpation on patients in moving ambulances. Measurement of POWSBP was accomplished by observing the return of the waveform on the pulse oximeter at the time of cuff deflation. The order in which the readings were obtained as well as the arm chosen for measurement were randomized. SETTING AND PARTICIPANTS: Paramedics and emergency medical technicians in an urban, inner-city emergency medical services (EMS) system. MEASUREMENTS AND MAIN RESULTS: Blood pressure measurements were sampled from 69 patients. Regression analysis identified significant correlation between POWSBP and the four methods utilized, with r = 0.92 for NIPBM, r = 0.95 for auscultation, and r = 0.97 for palpation, all significant at p < 0.0001. CONCLUSIONS: The use of POWSBP measurement is a fast, easy, and accurate technique with which to measure systolic BP in the field. It may have special importance for noisy environments and moving vehicles in which conventional methods of auscultation or palpation may be difficult.

Use of on-line medical command to randomize patients in a prehospital research study.

OBJECTIVE: To describe the efficiency of using on-line medical command (OLMC) to conduct a prospective, randomized clinical trial addressing safety and patient enrollment. DESIGN, SETTING, AND PARTICIPANTS: Prospective design using OLMC to randomize adult asthmatics into one of three treatment groups. After verifying inclusion and exclusion criteria, OLMC physicians removed a covering label on study sheets and ordered the treatment specified underneath the label that had been assigned in a random sequence. RESULTS: A total of 204 patients were seen with dyspnea and wheezing during the three-month study. Of these, 68 (33%) were excluded from the study. Of the 136 (67%) patients who were eligible for study, 87 were enrolled (enrollment efficiency 64%), with 79 fully evaluable (evaluable efficiency 91%). The study safety was 100% because no enrolled patients met any exclusion criteria. CONCLUSIONS: The design was random and prospective, with patient entry blinded, using paramedics to enroll patients and OLMC physicians as gatekeepers, thus ensuring appropriate patient eligibility and study-arm assignment. Use of OLMC physicians to perform prospective randomized studies is safe and efficient, and results in a high yield of evaluable patients.

A comparison of pediatric and adult trauma patients transported by helicopter and ground EMS: managed-care considerations.

INTRODUCTION: There is a paucity of data comparing injured pediatric patients transported by helicopter emergency medical services (HEMS) with patients transported by ground ambulance. The purpose of this study was to compare HEMS pediatric trauma patients to: 1) pediatric patients transported by ground to an urban level-1 trauma center (TC), and; 2) a similar cohort of adult patients. The managed-care consequences of these comparisons are highlighted. METHODS: All trauma patients flown directly from the scene by HEMS from January 1, 1990, to April 30, 1993, were compared to a cohort of trauma patients arriving by ground advanced life support (ALS). All patients were transported to the same level-1 TC. The data collected included the mechanism of injury and the prehospital procedures performed, the injury severity score (ISS), and outcome. RESULTS: There was no difference in the ISS between the HEMS (n = 216) and ground ALS (n = 355) pediatric patients (16.8 vs 17.1; p = 0.55). Adult HEMS patients (n = 202) had significantly higher ISS than did injured adults (n = 1652) transported by ground (18.0 vs 13.6; p < 0.0001). Overall, trauma patients transported by air directly from the scene have a higher ISS than patients transported by ground (17.5 vs 13.6; p < 0.001). CONCLUSIONS: Pediatric patients transported by HEMS were as severely injured as those transported by ground, in contrast to adult patients. We conjecture that since trauma triage schemes classically focus on adults, ground personnel are more selective about which patients are flown to a TC, and less selective for pediatric patients. Trauma centers and HEMS programs should develop pediatric trauma triage protocols that do not overemphasize physiologic parameters.

Incidence and risk factors for early small bowel obstruction after celiotomy for penetrating abdominal trauma.

The reported overall incidence of postoperative Small Bowel Obstruction (SBO) is 0.69 per cent. This study examined the incidence and risk factors for early postoperative SBO for penetrating abdominal trauma (PAT), with early SBO defined as SBO within 6 months of operation. This was a prospective cohort study of patients admitted to a Level 1 Trauma Center from 5/91 to 12/93 who required celiotomy for PAT. Patients were followed at least 6 months for readmission for SBO to be considered evaluable. Of 341 patients undergoing celiotomy for PAT and surviving to discharge, 298 (87.4%) were evaluable. The overall incidence of early SBO was 7.4 per cent and varied between 2.3 per cent (nontherapeutic celiotomy) and 10.8 per cent (small/large bowel injury). All patients with celiotomy for PAT are at increased risk for early SBO compared with elective surgery patients. Those with small/large bowel penetration or gunshot wounds are at the highest risk. Previous abdominal surgery is not a risk factor for early SBO in PAT patients. Surgeons and Managed Care case managers should devote special attention to close follow-up in PAT patients, particularly those with the risk factors identified in this study.

Prospective, randomized trial of epinephrine, metaproterenol, and both in the prehospital treatment of asthma in the adult patient.

STUDY OBJECTIVE: To compare the effectiveness and incidence of adverse reactions with three treatment regimens for asthma in adults in the prehospital setting. DESIGN: Prospective, randomized clinical study. SETTING: Inner-city emergency medical service system providing basic and advanced life support and transport to 14 urban area hospital emergency departments. PARTICIPANTS: One hundred fifty-four adult asthmatic patients, 18 to 50 years old, who presented to paramedics with shortness of breath and wheezing. RESULTS: Eligible patients were randomly assigned by the base station physician to one of three treatment groups: subcutaneous epinephrine, nebulized metaproterenol, or subcutaneous epinephrine and nebulized metaproterenol. Peak expiratory flow rate (PEFR), blood pressure, heart rate, and respiratory rate were measured before and after treatment in each patient. During a 9-month period (October 1992 through June 1993), 154 patients were enrolled in the study; 53 (34%) received epinephrine, 49 (32%) received metaproterenol, and 52 (34%) received both. There were no significant differences in patient demographics, initial vital signs, or pretreatment PEFR among the three groups. The mean difference between pretreatment and posttreatment PEFR was 73 L/min and did not significantly differ among the treatment groups. Significant changes in vital signs were seen in no treatment group. CONCLUSION: Nebulized metaproterenol is as effective as subcutaneous epinephrine in the prehospital treatment of adult patients with acute asthma. The combination of these two treatments offered no additional clinical benefit in the patients we studied.

Factors influencing successful intubation in the prehospital setting.

OBJECTIVE: To explore the determinants influencing oral/nasal endotracheal intubation (OETI/NETI) and determine which cognitive, therapeutic, and technical interventions may assist prehospital airway management. DESIGN, SETTING, AND PARTICIPANTS: Prospective review of run reports and structured interviews of paramedics involved in OETI/NETI attempts were conducted in a high-volume, inner-city, advanced life support (ALS) system during an eight-month period (July 1991 to February 1992). Data were abstracted from run reports, and paramedics were asked in structured interviews to describe difficulties in OETI/NETI attempts. RESULTS: Of 236 patients studied, 88% (208) were intubated successfully. Success/failure rate was not related statistically to patients' ages (p = 0.78), medical or trauma complaint (89% vs 85%, p = 0.35), oral versus nasal route (88% vs 85%, p = 0.38), care time (scene+transport times: success, 18 minutes; failure, 20 minutes, p = 0.30), paramedic seniority (p = 0.13), or number of attempts per paramedic (p > 0.05). Increased level of consciousness (LOC) was associated with decreased success rate (p = 0.04). Paramedics reported difficulties in endotracheal intubation (ETI) attempts in 110 (46.6%) of patients. Factors reported to increase ETI difficulty were: 1) technical problems (35.6%); 2) mechanical problems (15.6%); and 3) combative patients (12.7%). CONCLUSIONS: Oral endotracheal intubation and NETI success rates identified in this study are similar to those described in the literature, although innovative strategies could be used to facilitate prehospital airway management. Many of the factors found to increase ETI difficulty could be ameliorated by the administration of paralytic agents, that is, for combative patients. Focused training in cadaver and animal labs coupled with recurrence training in the operating suites should be used on a regular basis to decrease difficulties in visualization. Interventions directed at alleviating mechanical difficulties that should be explored include new-to-the-field techniques, such as retrograde intubation, fiber-optic technology, and surgical tracheal access.