Emergency medical services intervals and survival in trauma: assessment of the "golden hour" in a North American prospective cohort.

STUDY OBJECTIVE: The first hour after the onset of out-of-hospital traumatic injury is referred to as the "golden hour," yet the relationship between time and outcome remains unclear. We evaluate the association between emergency medical services (EMS) intervals and mortality among trauma patients with field-based physiologic abnormality. METHODS: This was a secondary analysis of an out-of-hospital, prospective cohort registry of adult (aged > or =15 years) trauma patients transported by 146 EMS agencies to 51 Level I and II trauma hospitals in 10 sites across North America from December 1, 2005, through March 31, 2007. Inclusion criteria were systolic blood pressure less than or equal to 90 mm Hg, respiratory rate less than 10 or greater than 29 breaths/min, Glasgow Coma Scale score less than or equal to 12, or advanced airway intervention. The outcome was in-hospital mortality. We evaluated EMS intervals (activation, response, on-scene, transport, and total time) with logistic regression and 2-step instrumental variable models, adjusted for field-based confounders. RESULTS: There were 3,656 trauma patients available for analysis, of whom 806 (22.0%) died. In multivariable analyses, there was no significant association between time and mortality for any EMS interval: activation (odds ratio [OR] 1.00; 95% confidence interval [CI] 0.95 to 1.05), response (OR 1.00; 95% CI 9.97 to 1.04), on-scene (OR 1.00; 95% CI 0.99 to 1.01), transport (OR 1.00; 95% CI 0.98 to 1.01), or total EMS time (OR 1.00; 95% CI 0.99 to 1.01). Subgroup and instrumental variable analyses did not qualitatively change these findings. CONCLUSION: In this North American sample, there was no association between EMS intervals and mortality among injured patients with physiologic abnormality in the field.

Assessment of risk tolerance for adverse events in emergency department chest pain patients: a pilot study.

BACKGROUND: Emergency physicians commonly encounter low-probability/high-morbidity decisions, and chest pain is a prime example. Negative outcomes are improbable but feared, resulting in substantially more patients admitted for chest pain than have important disease. The literature gives little guidance on patient preferences for decision-making when the negative outcomes are unlikely but potentially severe. OBJECTIVES: The objective of this pilot study was to assess the tolerance of Emergency Department (ED) patients with chest pain for adverse events occurring within 2 weeks of the episode. METHOD: We recruited a convenience sample of patients with a chief complaint of chest pain from the ED of an urban tertiary-care referral center. Each subject was interviewed to determine demographic information, perceived health status, insurance status, and tolerance for adverse events related to chest pain. Adverse events were defined loosely but were suggested to be heart attack, the need for emergency cardiac surgery, or death. The risk tolerance question was framed by describing a specific numeric risk and determining at what risk the patient switched from desiring hospital admission to desiring discharge; we termed this the decision threshold. RESULTS: Sixty-eight (68) subjects were included. Fifty-four percent of subjects were male, 60% were African-American, and 35% were white; 40% of the subjects classified themselves as being of average health. Of the 31 subjects who had prior heart trouble, 48% (n = 15) stated they had a prior heart attack and 19% (n = 6) an irregular heartbeat. The median decision threshold, or the acceptable personal risk of an adverse event for a person to forego admission to hospital, was 6.5% (interquartile range 0.5-22.9%). The mode was 0.5%, and 44% (30/68) of subjects had a decision threshold of 2% or less. There was no obvious pattern for most of these explanatory variables, though there was a suggestion that race may affect patients' risk tolerance. CONCLUSIONS: There is substantial variation in patients' reported tolerance for adverse events from ED chest pain. Further investigation of this phenomenon may lead to better decision-making.

Expert verification of the knowledge base of FEED--a feedback expert system for EMS documentation.

Feedback Expert System for Emergency Medical Services (EMS) Documentation (FEED) has a rule-based knowledge base (KB) that was verified against specifications in a focus group consisting of six experts. The focus group suggested changes in almost all rules discussed, indicating that the KB did not meet specifications at that stage of development. However, enough information was gathered to address these issues in the next iteration of development.

Instructions to "push as hard as you can" improve average chest compression depth in dispatcher-assisted cardiopulmonary resuscitation.

BACKGROUND AND OBJECTIVE: Cardiopulmonary resuscitation (CPR) with adequate chest compression depth appears to improve first shock success in cardiac arrest. We evaluate the effect of simplification of chest compression instructions on compression depth in dispatcher-assisted CPR protocol. METHODS: Data from two randomized, double-blinded, controlled trials with identical methodology were combined to obtain 332 records for this analysis. Subjects were randomized to either modified Medical Priority Dispatch System (MPDS) v11.2 protocol or a new simplified protocol. The main difference between the protocols was the instruction to "push as hard as you can" in the simplified protocol, compared to "push down firmly 2in. (5cm)" in MPDS. Data were recorded via a Laerdal ResusciAnne SkillReporter manikin. Primary outcome measures included: chest compression depth, proportion of compressions without error, with adequate depth and with total release. RESULTS: Instructions to "push as hard as you can", compared to "push down firmly 2in. (5cm)", resulted in improved chest compression depth (36.4 mm vs. 29.7 mm, p<0.0001), and improved median proportion of chest compressions done to the correct depth (32% vs. <1%, p<0.0001). No significant difference in median proportion of compressions with total release (100% for both) and average compression rate (99.7 min(-1) vs. 97.5 min(-1), p<0.56) was found. CONCLUSIONS: Modifying dispatcher-assisted CPR instructions by changing "push down firmly 2in. (5cm)" to "push as hard as you can" achieved improvement in chest compression depth at no cost to total release or average chest compression rate.

Instructions to "put the phone down" do not improve the quality of bystander initiated dispatcher-assisted cardiopulmonary resuscitation.

OBJECTIVE: The quality of early bystander CPR appears important in maximizing survival. This trial tests whether explicit instructions to "put the phone down" improve the quality of bystander initiated dispatch-assisted CPR. METHODS: In a randomized, double-blinded, controlled trial, subjects were randomized to a modified version of the Medical Priority Dispatch System (MPDS) version 11.2 protocol or a simplified protocol, each with or without instruction to "put the phone down" during CPR. Data were recorded from a Laerdal Resusci Anne Skillreporter manikin. A simulated emergency medical dispatcher, contacted by cell phone, delivered standardized instructions. Primary outcome measures included chest compression rate, depth, and the proportion of compressions without error, with correct hand position, adequate depth, and total release. Time was measured in two distinct ways: time required for initiation of CPR and total amount of time hands were off the chest during CPR. Proportions were analyzed by Wilcoxon rank sum tests and time variables with ANOVA. All tests used a two-sided alpha-level of 0.05. RESULTS: Two hundred and fifteen subjects were randomized-107 in the "put the phone down" instruction group and 108 in the group without "put the phone down" instructions. The groups were comparable across demographic and experiential variables. The additional instruction to "put the phone down" had no effect on the proportion of compressions administered without error, with the correct depth, and with the correct hand position. Likewise, "put the phone down" did not affect the average compression depth, the average compression rate, the total hands-off-chest time, or the time to initiate chest compressions. A statistically significant, yet trivial, effect was found in the proportion of compressions with total release of the chest wall. CONCLUSIONS: Instructions to "put the phone down" had no effect on the quality of bystander initiated dispatcher-assisted CPR in this trial.

Cost-utility analysis of emergency department thoracotomy for trauma victims.

BACKGROUND: Our objective was to assess the cost-effectiveness of emergency department thoracotomy (EDT) performed on both penetrating and blunt trauma victims, using both published survival and outcome data and previously unaccounted for data on the cost of occupational exposure. METHODS: Cost-utility analysis was performed using decision-analytic models constructed for both penetrating and blunt trauma scenarios. Survival and impairment data, the rates and costs of occupational exposure, and the utilities of neurologic impairment and provider seroconversion were all based on published literature. Costs of EDT were estimated using the National Inpatient Sample (NIS) from the Health Care Utilization Project database. One-way sensitivity analyses on input parameters and probabilistic sensitivity analyses using Monte Carlo simulations were performed. RESULTS: The incremental cost-effectiveness ratio of EDT for penetrating trauma was $16,125 per quality-adjusted life year (QALY), and less than $50,000 per QALY with a 93.4% probability. The incremental cost-effectiveness ratio for blunt trauma was $163,136 per QALY, and less than $50,000 per QALY with a 37% probability. Neither model was sensitive to provider exposure. The penetrating model was insensitive to the probability of neurologically intact survival, the utility adjustment, procedure costs, and long-term care. The blunt model was sensitive to the probabilities of survival and of neurologic impairment. CONCLUSIONS: EDT is cost-effective for penetrating trauma, and not cost-effective for blunt trauma given current rates of survival and impairment. Occupational exposure does not significantly impact the cost-effectiveness of the procedure.

Expert validation of the knowledge base for E-CAD - a pre-hospital dispatch triage decision support system.

The knowledge base (KB) for E-CAD (Enhanced Computer-Aided Dispatch), a triage decision support system for Emergency Medical Dispatch (EMD) of medical resources in trauma cases, is being evaluated. We aim to achieve expert consensus for validation and refinement of the E-CAD KB using the modified Delphi technique. Evidence-based, expert-validated and refined KB will provide improved EMD practice guidelines and may facilitate acceptance of the E-CAD by state-wide professionals.

Information needs of pre-hospital care providers - a requirements analysis.

To assess information needs of Emergency Medical Services (EMS) personnel and the potential of electronic decision support tools, we surveyed 39 paramedic students and practicing EMS personnel. We found frequent use of paper-based tools, with imperfect accessibility and ease of use. Potential electronic decision support tools were rated as helpful, but some alerts were rated low. The results may be helpful in design, implementation and research of electronic decision support tools for EMS.

Relationship between knowledge of cardiopulmonary resuscitation guidelines and performance.

OBJECTIVE: Despite widespread training with CPR guidelines, CPR is often poorly performed. We explore relationships between knowledge of CPR guidelines and performance (compression rate, compression depth, compression to ventilation ratio, and ventilation volume). METHODS: Sixty professional EMTs were sampled at 26 randomly ordered EMS response stations from an urban system of 31 stations. A recording manikin and video model were used to assess performance in a standardized scenario, and a survey was used to assess guideline knowledge. Survey and performance outcomes were categorized prospectively as correct or incorrect based on the International CPR Guidelines from 2000. Relationships were modeled with logistic regression. Covariates included years of work experience, frequency of CPR performance, and ALS versus BLS EMT level. RESULTS: Compression rate was between 80 and 120 min(-1) in 56% (33/59) of trials. Compression depth was 1.5-2 in. in 39% (23/59), compression to ventilation ratio approximated to 15:2 in 42% (25/59), and ventilation volume was 800-1,200 cm(3) in 13% (8/60). Accurate knowledge of the CPR guidelines was associated with better performance of chest compression rate and compression to ventilation ratio. Adjusted OR (95% CI) were 4.6 (1.2-18.1) for compression rate, 1.7 (0.4-6.5) for compression depth, 4.5 (1.1-18.5) for compression to ventilation ratio, and 9.0 (0.2-351) for ventilation volume. CONCLUSIONS: Although accurate knowledge of guidelines is associated with increased odds of correct performance of some aspects of CPR, overall performance remains poor.

Procedural sedation in the acute care setting.

Many patients require sedation during diagnostic or therapeutic procedures. Ideally, procedural sedation minimizes the patient's awareness and discomfort while maintaining the patient's safety. Appropriate monitoring by trained personnel is the key to successful procedural sedation. These techniques should be used only by health care professionals skilled in managing complications, including cardiorespiratory compromise. It is important to take a complete history and perform a thorough physical examination, paying special attention to the selection of pharmacologic agents. Common sedative agents include etomidate, ketamine, fentanyl, and midazolam. These have become the agents of choice for procedural sedation because of their ease of use, predictable action, and excellent safety profiles. All patients requiring procedural sedation should be monitored by qualified staff at the bedside until they have recovered to an age-appropriate baseline mental status and function.