Thomas E. Auble

Use of Automated External Defibrillators by Police Officers for Treatment of Out-of-Hospital Cardiac Arrest

OBJECTIVE To determine the feasibility of police officers providing defibrillation with automated external defibrillators (AEDs) and to assess the effectiveness of this strategy in reducing time to defibrillation of victims of out-of-hospital sudden cardiac arrest. METHODS This was a prospective, interventional cohort study with historical controls conducted in 7 suburban communities in which police usually arrived at the scene of medical emergencies before EMS personnel. All adult patients who suffered cardiac arrest before EMS arrival and on whom EMS personnel attempted resuscitation were enrolled. Police officers who were trained to use and equipped with AEDs during the intervention phase were dispatched simultaneously with EMS to medical emergencies. Police were instructed to use the AED immediately on determination of pulselessness. Outcome measures were the difference between control and intervention phases in interval from the time the call was received at dispatch to the time of first defibrillation and in rate of survival to hospital discharge for patients initially in ventricular fibrillation. RESULTS EMS personnel attempted 183 resuscitations in the control phase and 283 during the intervention; of these, 80 (44%) and 127 (45%), respectively, involved patients with initial ventricular fibrillation rhythms. Mean time to defibrillation decreased from 11.8+/-4.7 minutes in the control phase to 8.7+/-3.7 minutes in the intervention phase (P<.0001). Survival to hospital discharge of patients in ventricular fibrillation did not differ between phases (6% control versus 14% intervention, P=.1). When police arrived before EMS personnel, shock administered by police compared with shock administered by EMS was associated with improved survival (26% [12/46] versus 3% [1/29], P=.01). Logistic regression analysis revealed AED use was an independent predictor of survival to hospital discharge. CONCLUSION In 7 suburban communities, police use of AEDs decreased time to defibrillation and was an independent predictor of survival to hospital discharge.

Effect of out-of-hospital defibrillation by basic life support providers on cardiac arrest mortality : a metaanalysis

STUDY OBJECTIVE Although some studies demonstrate otherwise, we hypothesized that metaanalysis would demonstrate a reduction in the relative risk of mortality when basic life support (BLS) providers can defibrillate out-of-hospital cardiac arrest patients. DESIGN Metaanalysis of studies meeting the following criteria: single-tier or two-tier emergency medical service (EMS) system, survival to hospital discharge for patients in ventricular fibrillation, and manual and/or automatic external defibrillators. The alpha error rate was .05. RESULTS Seven trials qualified for metaanalysis. Across all trials, the risk of mortality for BLS care with defibrillation versus that without was .915 (P = .0003). Separate subset analyses of single-tier and two-tier EMS systems demonstrated similar results. CONCLUSION BLS defibrillation can reduce the relative risk of death for out-of-hospital cardiac arrest victims in ventricular fibrillation. Weaknesses in individual study designs and regional clustering limit the strength of this metaanalysis and conclusion.

Two-thumb versus two-finger chest compression during CPR in a swine infant model of cardiac arrest

STUDY OBJECTIVE To test the hypothesis that two-thumb chest compression generates higher arterial and coronary perfusion pressures than the current American Heart Association-approved two-finger method. DESIGN Randomized, crossover experimental trial. SETTING AND PARTICIPANTS Animal laboratory experiment with seven swine of either sex weighing 9.4 kg (SD, 0.8 kg), representing infants less than 1 year old. INTERVENTIONS Animals were sedated with IM ketamine/xylazine, intubated with a 6.0 Hi-Lo endotracheal tube, anesthetized with alpha-chloralose, and paralyzed with pancuronium. ECG was monitored continuously. Left femoral arterial and Swan-Ganz catheters were placed. Cardiac arrest was induced with an IV bolus of KCl and verified by ECG and pressure tracings. Five American Heart Association-certified basic rescuers were randomly assigned to perform external chest compressions for one minute by either the currently recommended two-finger method or the two-thumb and thorax-squeeze method. After all five completed their first trial, rescuers crossed over to the other method for a second minute of compressions. Ventilation was performed with a bag-valve device, and no drugs were given during CPR. After three complete cycles, the fourth through sixth cycles of compressions were recorded. Every compression was analyzed for arterial systolic, diastolic, mean, and coronary perfusion pressures. One thousand fifty compressions were analyzed with repeated-measures analysis of variance and Scheffé multiple comparisons. RESULTS Systolic blood pressure, diastolic blood pressure, mean arterial pressure, and coronary perfusion pressure were all significantly higher (P < .001) with the two-thumb thoracic squeeze technique: systolic blood pressure, 59.4 versus 41.6 mm Hg; diastolic blood pressure, 21.8 versus 18.5 mm Hg; mean arterial pressure, 34.2 versus 26.1 mm Hg; and coronary perfusion pressure, 15.1 versus 12.2 mm Hg. CONCLUSION The two-thumb method of chest compression generates significantly higher arterial and coronary perfusion pressures than the two-finger method in this infant model of cardiac arrest.

Functional Outcome of Patients with Unstable Pelvic Ring Fractures Stabilized with Open Reduction and Internal Fixation

An unstable pelvic ring fracture represents a severe injury and is associated with high morbidity and mortality. Little data are available assessing the long-term functional limitations, including disability, in a patient with an unstable pelvic ring fracture. The purpose of this study was to describe the impairment and functional outcome (disability) for patients with unstable pelvic ring fractures managed with open reduction and internal fixation (ORIF). Disability was measured at a minimum of 1 year postinjury using the Sickness Impact Profile (SIP), a measure of the health-related quality of life as perceived by the patient. Of the 230 consecutive patients with a pelvic ring fracture, 54 had unstable fractures requiring ORIF; 48 patients were available at a 1 year follow-up. The follow-up roentgenograms confirmed an osseous union and an anatomic alignment of the pelvis. Thirty-seven (77%) of the patients had mild disability (total SIP < 10); 11 (23%) of the patients had moderate disability (SIP > 10) at 1 year. Of the patients who were employed preinjury, 76% were employed 1 year postinjury; 62% had returned to full time work and 14% had returned with job modification. Of the 7 patients who had been in school, 6 had returned full time and 1 student returned part time. Mean SIP scores for subcategories were: physical health = 6.8 +/- 9.4, psychosocial health = 7.4 +/- 12.7, work = 17.6 +/- 25.5, home management = 8.3 +/- 13.0, ambulation = 10.7 +/- 13.7, and mobility = 5.3 +/- 13.0. Despite the magnitude of the bony injuries, the majority of patients with unstable pelvic ring fractures managed with ORIF had mild disability 1 year postinjury; the majority of the patients had returned to work.

Multicenter comparison of two clinical decision rules for the use of radiography in acute, high-risk knee injuries

STUDY OBJECTIVE Two separate clinical decision rules, one developed in Ottawa and the other in Pittsburgh, for the use of radiography in acute knee injuries have been previously validated and published. In this study, the rules were prospectively validated and compared in a new set of patients. METHODS A prospective, blinded, multicenter trial was conducted in the emergency departments of three urban teaching hospitals. A convenience sample of 934 patients with knee pain requiring radiographs was enrolled. A standardized data form was completed for each patient, comprising the 10 clinical variables included in the two rules. Standard knee radiographs were then taken in each patient. The rules were interpreted by the primary investigator on the basis of the data sheet and the final radiologist radiograph reading. RESULTS In the 745 patients in whom the Pittsburgh rules could be applied there were 91 fractures (12.2%). The use of the Pittsburgh rule missed one fracture, yielding a sensitivity of 99% (95% confidence interval [CI], 94% to 100%); the specificity was 60% (95% CI, 56% to 64%). The Ottawa inclusion criteria were met by 750 patients, with 87 fractures (11.6%). The Ottawa rule missed three fractures, for a sensitivity of 97% (95% CI, 90% to 99%); specificity was 27% (95% CI, 23% to 30%). CONCLUSION Prospective validation and comparison found the Pittsburgh rule for knee radiographs to be more specific without loss of sensitivity compared with the Ottawa rule.

Assessing prognosis and selecting an initial site of care for adults with community-acquired pneumonia.

Over the last 20 years, more than 15 medical practice guidelines and clinical prediction rules have emerged to assist physicians in assessing the prognosis of adult patients with community-acquired pneumonia (CAP) and selecting an appropriately matched initial site of care. Most of these guidelines and rules suffer from major methodological flaws. One, the Pneumonia Patient Outcomes Research Team (PORT) clinical prediction rule, has satisfied rigorous methodological standards for the derivation and validation of high-quality prediction rules. This rule was incorporated into the Infectious Disease Society of America medical practice guideline for the management of adults with CAP. Strengths of the rule include its derivation and validation in over 50,000 inpatients and outpatients; stratification of all immunocompetent adult patients into one of five risk strata for short-term mortality and other unambiguous adverse medical outcomes; initial site of care recommendations for all patients, particularly those at low risk; and reliance on predictor variables readily available to clinicians at the time of initial patient presentation. A recent small-scale intervention trial demonstrates that the pneumonia PORT rule can reduce admissions for adult patients with CAP without compromising patient outcomes.

Cross-modal exercise prescription at absolute and relative oxygen uptake using perceived exertion.

Cross-modal exercise prescription at absolute and relative oxygen uptake using perceived exertion. Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 653-659, 1990. The validity of cross-modal prescription of exercise intensity based on rated perceived exertion (RPE) was determined for eight men (26 +/- SE 1.9 yr) at absolute and relative VO2. Exercise modes were treadmill (TM), cycle ergometer (C), and bench stepping while pumping 0.91 kg handweights (HB). Relative (Rel) constant load sessions were performed for each mode at 70% of mode-specific VO2 peak. Absolute (Absol) constant load sessions were performed for C and HB at the VO2 equivalent to 70% of TM VO2 peak. The five 12 min sessions were presented on separate days in random order. RPE-Overall during TM-Rel (11.1) was a) lower (P less than 0.05) than C-Absol (12.6) and HB-Absol (12.5) and b) the same as C-Rel (11.3) and HB-Rel (10.7). RPE-Legs during TM-Rel was a) lower (P less than 0.05) than C-Absol and HB-Absol and b) the same as C-Rel and HB-Rel. RPE-Chest a) did not differ between TM-Rel and C-Absol or HB-Absol and b) was lower (P less than 0.05) for C-Rel and HB-Rel than TM-Rel. RPE-Arms was higher (P less than 0.05) for C-Absol, HB-Absol, and HB-Rel than TM-Rel but did not differ between TM-Rel and C-Rel. Oxygen uptake, heart rate, and ventilation during TM-Rel were a) the same as C-Absol and HB-Absol and b) higher (P less than 0.05) than C-Rel and HB-Rel. Perceptually based cross-modal prescription of exercise intensity using a psychophysical estimation method is valid provided that the physiological reference is the relative, not the absolute, VO2.

Factors Associated with the Hospitalization of Low-risk Patients with Community-acquired Pneumonia in a Cluster-Randomized Trial

AbstractBACKGROUND: Many low-risk patients with pneumonia are hospitalized despite recommendations to treat such patients in the outpatient setting. OBJECTIVE: To identify the factors associated with the hospitalization of low-risk patients with pneumonia. METHODS: We analyzed data collected by retrospective chart review for 1,889 low-risk patients (Pneumonia Severity Index [PSI] risk classes I to III without evidence of arterial oxygen desaturation) enrolled in a cluster-randomized trial conducted in 32 emergency departments. RESULTS: Overall, 845 (44.7%) of all low-risk patients were treated as inpatients. Factors independently associated with an increased odds of hospitalization included PSI risk classes II and III, the presence of medical or psychosocial contraindications to outpatient treatment, comorbid conditions that were not contained in the PSI (cognitive impairment, history of coronary artery disease, diabetes mellitus, or pulmonary disease), multilobar radiographic infiltrates, and home therapy with oxygen, corticosteroids, or antibiotics before presentation. While 32.8% of low-risk inpatients had a contraindication to out-patient treatment and 47.1% had one or more preexisting treatments, comorbid conditions, or radiographic abnormalities not contained in the PSI, 20.1% had no identifiable risk factors for hospitalization other than PSI risk class II or III. CONCLUSIONS: Hospital admission appears justified for one-third of low-risk inpatients based upon the presence of one or more contra-indications to outpatient treatment. At least one-fifth of low-risk inpatients did not have a contraindication to outpatient treatment or an identifiable risk factor for hospitalization, suggesting that treatment of a larger proportion of such low-risk patients in the outpatient setting could be achieved without adversely affecting patient outcomes.

Aerobic Requirements for Moving Handweights through Various Ranges of Motion While Walking.

In brief: This study compared the aerobic metabolic requirements of normal walking (without handweights and with normal arm motions) with requirements of walking while pumping 1-,2-, or 3-lb handweights through Various ranges of motion. Nine male subjects Walked with and without handweights at speeds of 1.12 to 1.79 m· sec(-1). Adding hand-Weighted arm movements significantly increased the oxygen consumption (V O2) of normal walking by 2.1 to 25.5 ml· kg(-1)· min(-1). The V O2 for handweighted walking ranged from 17 to 43 ml· kg(-1)· min(-1), or 113% to 255% of normal walking requirements at any given speed. These results indicate that walking while moving handweights through large ranges of motion provides a combined upper and lower body aerobic stimulus that is sufficient for endurance training for persons with poor to excellent levels of aerobic fitness.

Law enforcement agencies and out-of-hospital emergency care.

STUDY OBJECTIVE We sought to assess the involvement of law enforcement agencies in out-of-hospital emergency medical care and their attitudes toward expanded roles in emergency medical services (EMS) systems. METHODS We mailed a 20-question survey to 800 police chiefs and sheriffs randomly selected from a list of all law enforcement agencies in the United States. The questions focused on the characteristics of each law enforcement agency, its current level of involvement in providing out-of-hospital emergency medical care, and the characteristics of its associated community and local EMS system. The survey concluded with four statements to assess officer attitudes toward an expanded role in EMS-related activities. We used the chi 2 or Fisher exact test to analyze differences in proportions. The alpha-error rate was set at .05. RESULTS Seventeen surveys were returned as undeliverable. Of the remaining 783 surveys, we received 602 responses (77%). Five hundred forty-nine (70.1%) of the respondents were the primary law enforcement agencies in their communities; they make up the final sample. The median number of officers per agency was 12 (range, 1 to 2,623), and the median population served was 6,936 (range, 150 to 1,500,000). Responses indicated that 442 (80.7%) agencies responded to one or more specific types of medical emergencies and 263 (50.3%) provided some level of patient care. Law enforcement officers frequently arrived at the scene of medical emergencies before EMS personnel (81.5%), with a roll-time interval of less than 8 minutes (87.2%). Only 14 agencies (2.6%) used automatic external defibrillators. Fifty-three percent agreed with the statement that EMS-related activities would interfere with their law enforcement duties. However, more than 60% of respondents agreed that law enforcement agencies should be involved in providing emergency medical services for life-threatening emergencies, that their officers would be willing to undertake extra medical training and that EMS-related activities would improve their public images. CONCLUSION Many law enforcement agencies are involved to some extent in providing out-of-hospital emergency medical care, and most of the agencies we surveyed would support additional medical training and new or expanded roles for themselves in EMS systems.