Effect of vital signs on advanced life support interventions for prehospital patients.

OBJECTIVE: Routine vital signs assessment is considered a fundamental component of patient assessment. This study was undertaken to determine whether advanced life support (ALS) emergency medical services (EMS) providers depend on vital signs information in managing their patients. METHODS: Emergency medical technician-paramedics (EMT-Ps) and EMT-Intermediates (EMT-Is) were presented with 20 randomized patient scenarios that did not included vital signs information. The participants were asked to identify all of the interventions they would perform for each hypothetical patient. At least six weeks later the same scenarios were presented in a new order, with vital signs information, and the participants again identified the interventions they would perform. The participants' estimations of the patients' blood pressures, as well as the frequencies with which 18 specific interventions were performed, were compared for the no-vital signs and the vital signs groups using chi-square of Fisher's exact test, with an alpha value of 0.05 considered significant. RESULTS: Fourteen EMT-Ps and 16 EMT-Is completed both the no-vital signs and vital signs portions of the study, for a total of 1,160 hypothetical patient encounters. When vital signs were given, the EMT-Is were more likely to apply a cardiac monitor (65.2% vs 80.1%, p = 0.000), more likely to start at least one intravenous (i.v.) line (82.1% vs 87.8%, p = 0.038), and more likely to administer a medication (1.3% vs 5.6%, p = 0.003). The EMT-Ps were also more likely to apply a cardiac monitor (84.4% vs 90.3%, p = 0.041), more likely to run an i.v. at a "wide open" rate (9.5% vs 19.0%, p = 0.004), and less likely to identify patients as being hypotensive (39.9% vs 26.4%, p = 0.004). CONCLUSION: The presence or absence of vital signs information does influence some of the patient care decisions of EMS providers; however, the clinical implications of these decisions are unclear. Further studies are needed to determine whether ALS providers can adequately manage actual patients without obtaining vital signs.

Photograph documentation of motor vehicle damage by EMTs at the scene: a prospective multicenter study in the United States.

The purpose of this study was to determine if emergency medical service (EMS) personnel could take instant photographs of motor vehicle damage at crash scenes depicting the area and severity of damage of the crash under adverse weather conditions, in different lighting, and quickly enough so as not to interfere with patient care. This prospective multicenter trial involved 35 ambulances responding to motor vehicle crash scenes in rural, suburban, and urban areas in five centers in four states. Emergency medical technicians (EMTs) reported their experience implementing a protocol for use of an instant camera to photograph vehicle damage at crash scenes. Time reported by EMTs to take the photographs was 1 minute or less in 204 of 288 (70.9%) of motor vehicle crashes and 2 minutes or longer in 12 of 288 (4.2%) of motor vehicle crashes. From one EMS agency in the study, 48 scene times during which photographs were taken were, on average, 1.5 minutes shorter than 48 scene times immediately before implementation of on-scene crash photography. Photographs were taken in different weather and lighting conditions. EMTs reported they were able to determine both area and severity of damage in 260 of 290 (92.5%) crash photographs, but they were unable to determine area and severity of damage in only 2 of 290 (0.7%) crash photographs.

Does basic life support in a rural EMS system influence the outcome of patients with respiratory distress?

PURPOSE: The purpose of this study was to determine whether basic life support, prehospital emergency medical care in a rural area affects the hospital course of patients with respiratory distress. METHODS: Medical records for patients admitted from the emergency department with a discharge diagnosis related to respiratory disease were reviewed. Data collected included: 1) mode of arrival; 2) initial symptom; 3) vital signs; 4) prehospital interventions applied; 5) hospital days; 6) discharge status; and 7) principal diagnosis. Multiple logistic regression analysis was used to predict length of hospital stay. RESULTS: Charts for 603 patients were reviewed. Complete data for all variables included in the logistic regression analysis were available for 471 patients (78.1%). Because 55 patients died, only 416 (69.0%) were included in the multiple regression analysis conducted to predict length of hospital stay. Logistic regression analysis demonstrated that patients who arrived by ambulance and older patients were more likely to die; patients with higher systolic blood pressures were more likely to survive. Only patient age predicted length of hospital stay, with older patients having longer stays. CONCLUSIONS: Basic life support prehospital care in this rural emergency medical services system does not result in a lower mortality rate or a shorter hospital stay for a broad group of patients with respiratory distress who require hospital admission. Although this study is limited to a single population and a single emergency medical services system, it is one of only a few studies of outcome in basic life support systems.

Can prehospital personnel detect hypoxemia without the aid of pulse oximeters?

Although pulse oximeters have been proven accurate in the prehospital environment, they have not been proven to be necessary. This study was undertaken to determine if emergency medical services (EMS) providers can identify hypoxemia without pulse oximetry. An oximeter was placed at the ambulance entrance to the emergency department (ED), and EMS personnel obtained saturation levels on all patients on arrival. Hypoxemia was defined as a saturation level of 95% or less. The hypoxemia was classified as "recognized" if the patient received aggressive intervention and "unrecognized" if the patient did not. One hundred eighty patients were enrolled in the study; 30 had a saturation level of 95% or less. Twenty-seven (90%) of those patients had "unrecognized" hypoxemia. Twenty-three (85.2%) of the 27 patients with "unrecognized" hypoxemia did not complain of respiratory distress. Thus, there are patients whose hypoxemia is unrecognized by EMS providers, and this occurs most frequently in patients who do not complain of respiratory distress.

Mistaken identity: the effect of badges on EMT recognition.

INTRODUCTION: Many emergency medical services (EMS) providers wear badges with their uniforms. This study was undertaken to determine whether emergency medical technicians (EMTs) who wear badges with their uniforms are more likely to be mistaken for law enforcement personnel than are those who do not wear badges. HYPOTHESIS: Emergency medical services providers who wear badges are more likely to be mistaken for law enforcement personnel than are those who do not wear badges. METHODS: High school students, college students, civic organizations, and church groups were shown slides of different uniforms and badges/insignia and asked to identify the person portrayed. Responses were categorized as "EMS," "law enforcement," or "other." Frequency of responses for each uniform and insignia were compared with chi-square analysis. RESULTS: Fifty-nine percent of the uniforms with badges were identified as law enforcement personnel. Only 5.5% of the uniforms with badges were identified as "EMS," compared with 74% of the uniforms with a Star of Life (p < 0.001). CONCLUSION: Individuals wearing uniforms with badges are more likely to be identified as law enforcement personnel than are EMS personnel. Emergency medical services providers who do not wish to be mistaken for law enforcement personnel should wear the Star of Life, not a badge, with their uniform.

Is ambulance transport time with lights and siren faster than that without?

STUDY OBJECTIVE: To determine whether ambulance transport time from the scene to the emergency department is faster with warning lights and siren than that without. DESIGN: In a convenience sample, transport times and routes of ambulances using lights and sirens were recorded by an observer. The time also was recorded by a paramedic who drove an ambulance without lights and siren over identical routes during simulated transports at the same time of day and on the same day of the week as the corresponding lights-and-siren transport. SETTING: An emergency medical service system in a city with a population of 46,000. PARTICIPANTS: Emergency medical technicians and paramedics. RESULTS: Fifty transport times with lights and siren averaged 43.5 seconds faster than the transport times without lights and siren [t = 4.21, P = .0001]. CONCLUSION: In this setting, the 43.5-second mean time savings does not warrant the use of lights and siren during ambulance transport, except in rare situations or clinical circumstances.

Prehospital blood pressures: inaccuracies caused by ambulance noise?

Blood pressure measurements in a moving ambulance can be difficult to obtain. Sirens, engine noise, and road noise can all interfere with the accurate detection of a patient's blood pressure. This study was undertaken to determine the influence of ambulance noise and vibration on auscultated blood pressures. A model was developed that used dynamic pressures to simulate systolic Korotkoff sounds. Forty-nine emergency personnel were asked to obtain blood pressures using the model in both a quiet environment and in a moving ambulance. A total of 485 blood pressure measurements were obtained. Systolic pressures were randomized to two settings: 76 mm Hg and 138 mm Hg. Stationary readings were compared with moving readings using analysis of variance for repeated measures. Systolic blood pressure measurements obtained in the quiet environment averaged 133 +/- 5 mm Hg at the high setting, and 45 +/- 6 mm Hg at the low setting. Systolic blood pressure measurements obtained in a moving ambulance averaged 86 +/- 7 mm Hg at the high setting, and 41 +/- 7 mm Hg at the low setting. The average differences between quiet and moving measurements were 47 mm Hg at the "high" setting (P < .01) and 4 mm Hg at the "low" setting (P > .01). At physiological levels, blood pressures obtained in moving ambulances differ significantly from those obtained in a quiet environment, which may be caused by road noise and ambulance motion.

Public perceptions of a rural emergency medical services system.

INTRODUCTION: To determine the awareness of citizens and physicians concerning the capabilities of a rural emergency medical services (EMS) system. HYPOTHESIS: Citizens and physicians are unaware of the capabilities of the EMS system. METHODS: Residents were selected randomly from the local telephone directory and asked a series of structured questions about their EMS agency. A written survey was distributed to area physicians. Chi-square analysis was used to compare the proportion of respondents who knew the available interventions in their community with the proportion of those who did not. Statistical significance was inferred at p < 0.01. RESULTS: A total of 49% of the citizens were able to identify available skills, and 41.4% of the physicians were able to identify available skills. Physicians were less likely than were the citizens to be able to identify the skills performed by each provider (p < 0.001). CONCLUSION: This study indicates that both physicians and the lay public have little understanding of the capabilities of their EMS system.

Environmental temperature variations cause degradations in epinephrine concentration and biological activity.

This study determined the biological consequence of temperature induced epinephrine degradation. Two different epinephrine preparations (1:1,000 and 1:10,000) were exposed to either cold (5 degrees C) or hot (70 degrees C) temperature. The exposure occurred for 8-hour periods each day in 4-, 8-, and 12-week intervals. Samples and identical controls were then chemically evaluated using high-pressure liquid chromatography (HPLC), and biological activity of samples showing chemical degradation was assessed in conscious rats. Epinephrine (1:10,000) underwent a significant degradation and a loss of concentration of the parent compound after 8 weeks of heat treatment. By 12 weeks, 64% of the epinephrine was degraded. A smaller (30%) but significant loss of cardiovascular potency was determined by blood pressure and heart rate responses in conscious rats. The degradation of epinephrine (1:1,000) was not statistically significant even after 12 weeks of heat exposure. No change was noted from control in either epinephrine concentration when exposed to cold temperatures. In conclusion, epinephrine (1:10,000) deteriorates in the presence of elevated temperature and should be protected from high temperatures when carried by EMS providers. The degradation products may possess biological activity.

Adverse lighting condition effects on the assessment of capillary refill.

In 1989, Champion et al recommended revising the Trauma Score to exclude capillary refill because it is "difficult to assess at night. . . ." However, a literature search produced no studies evaluating the effect of lighting conditions on the assessment of capillary refill. This study was undertaken to determine if any such effect exists. Three hundred nine participants at an emergency medical services (EMS) seminar were asked to assess each others' capillary refill in both light and dark environments. The participants were nurses, emergency medical technicians (EMTs), and paramedics who had been instructed in the assessment of capillary refill. In daylight conditions (partly cloudy day, lux meter = 15 to 16), capillary refill was reported as normal in 94.2% of the participants, delayed in 1.9% of the participants, and undetected in 3.9% of the participants. In dark conditions (moonlight or street lamp, lux meter = 4 to 6), capillary refill was reported as normal in 31.7% of the participants, delayed in 1.6% of the participants, and undetected in 66.7% of the participants. chi 2 analysis demonstrated a statistically significant difference between capillary refill assessment in light versus dark environments (P < .001).

Unexpected emergency department death: incidence, causes, and relationship to presentation and time in the department.

STUDY OBJECTIVE: To determine the incidence and causes of unexpected death in emergency department patients and its relationship to initial ED presentation. To determine if length of ED stay is directly related to unexpected death. DESIGN: Retrospective chart review of all patients dying in the study ED during a three-year period. Patients receiving CPR on admission or who had "do not resuscitate" orders were classified as expected deaths. Vital signs, level of consciousness, length of time in the ED, and cause of death were recorded for all unexpected deaths. SETTING: Five hundred sixty-six-bed medical center with an ED volume of 45,000 patients per year. PARTICIPANTS: Four hundred eleven patients were pronounced dead from 1987 to 1989, and 403 (98%) charts were available. RESULTS: Fifty-seven (14%) patients met the unexpected death criteria. Abnormal vital signs or altered level of consciousness was observed in 56 (98%) patients on presentation. Medical causes accounted for 42 (74%) of the unexpected deaths. Five (9%) surgical and ten (18%) trauma-related deaths were identified. The yearly incidence of unexpected death was 4.9 (per 10,000 ED visits) in 1987 and 4.1 in both 1988 and 1989. Average length of time in the ED before unexpected death increased during the study period (1987, 91 minutes; 1988, 110 minutes; 1989, 116 minutes). CONCLUSION: Unexpected ED death was uncommon, usually nontraumatic, and occurred in patients with evidence of significant illness. Although average length of stay in the ED increased, there was no increase in the incidence of unexpected ED death. If lengths of ED stay continue to increase, this situation will require further study.