Rescuer Fatigue in the Elderly: Standard Versus Continuous Chest Compression CPR

MEMC IV Abstracts was defined in the presence of at least one of the following: right bundle branch block, S1Q3T3 sign, T wave inversion in V1-V3 and pulmonary P wave. The study endpoint was death and/or cardiogenic shock during hospitalization. ROC curve analysis for troponin I and lactic acid values were performed. The association between the test results and the endpoint was evaluated by univariate and multivariate logistic regression analysis. Results: Eighty-six consecutive patients with nonmassive acute PE were included in the study. During hospital stay eighteen patients (20.9%) reached the endpoint, 7 (8.1%) died. At logistic regression analysis baseline Tn I ⬎0.06 ng/ml (OR 3.96, p⬍0.05), lactic acid ⬎1.8 mmol/l (OR 4.69, p ⬍0.01) and ECG signs of right ventricular strain (OR 8.36, p ⬍0.01) were significantly associated with the endpoint. All patients with normal results of the three tests had an uncomplicated hospital stay, while 50% of the patients with three abnormal tests reached the endpoint (OR 10, p ⬍0,01). Conclusions: In the emergency setting the combination of readily available bedside diagnostic tests may help optimize risk stratification and treatment strategies of patients with acute pulmonary embolism and clinical hemodynamic stability.

Cardiovascular, CPR/Resuscitation e THE IMPLEMENTATION AND EVALUATION OF AN INSPIRATORY IMPEDANCE THRESHOLD DEVICE (RESQPOD®) IN A COUNTY-WIDE EMERGENCY MEDICAL SYSTEM FOR NON-TRAUMATIC CARDIAC RESUSCITATIONS. D.J. Klaus, A.C. Stiff, K. Brickman, University of Toledo Medical Center, Toledo, OH; D.A. Lindstrom, G.M. Orlow, Lucas County Department of Emergency Services, Toledo, OH. Objectives: Several animal studies have shown that an impedance threshold device (ITD) can be a valuable adjunct to conventional cardiopulmonary resuscitation (CPR). However, there is still limited use and research conducted on the application of these devices on humans in the pre-hospital setting. This retrospective study evaluated the effectiveness of an ITD (ResQPOD®) implemented in August of 2006 in a countywide EMS system in Northwest Ohio, United States. Methods: The control was a 12 month historical assessment of nontraumatic cardiac arrest patients from August of 2005 to August of 2006 using conventional CPR. The study group included all non-traumatic cardiac arrest patients after August of 2006 using the ResQPOD® in addition to conventional CPR methods. We compared the two groups on rates of successful resuscitations defined by sustained return of spontaneous circulation (ROSC). Patients with a transient pulse during transportation (but not sustained to ED arrival) were assessed but not counted as successful resuscitations. A subgroup analysis was performed comparing initial cardiac rhythms found upon EMS arrival (asystole, ventricular fibrillation [VF], pulseless electrical activity [PEA], and unknown) to their respective ROSC rates. Results: Sustained ROSC in the study group (60/194 [31%]) improved by 35% compared to the historical control (75/327 [23%])(p⫽0.029). Use of the ResQPOD® also increased ROSC in each rhythm subgroup (Table 1). Most notably were

323 patients presenting in asystole, showing a statistically significant improvement in ROSC of 93% (Study Group⫽25/91 [27%] Vs. Control⫽21/148 [14%])(p⫽0.01). A 1-sided Fisher’s Exact Test was used in the analysis. Conclusion: Results from this county-wide EMS implementation and evaluation of the ResQPOD® clearly demonstrate its usefulness in the prehospital setting. Additional future studies evaluating long-term outcomes are still indicated before the ResQPOD® can be considered standard of care in emergency medicine. Table 1. Rhythm Subgroup Analysis of ROSC Initial %ROSC Control %ROSC Study %Increase Rhythm (n⫽327) Group (n⫽194) in ROSC Asystole PEA VF Unknown

14 (n⫽148) 29 (n⫽84) 27 (n⫽77) 50 (n⫽18)

27 (n⫽91) 33 (n⫽48) 29 (n⫽51) 100 (n⫽4)

93 14 7 100

p 0.010 0.351 0.473 0.098

e RESCUER FATIGUE IN THE ELDERLY: STANDARD VERSUS CONTINUOUS CHEST COMPRESSION CPR. J.W. Heidenreich, L. Watson, Texas A&M University/ Scott & White Memorial Hospital, Department of Emergency Medicine, Temple, TX; S.B. Arthur, University of Arizona, Department of Emergency Medicine, Tucson, AZ; J. Song, Scott & White Memorial Hospital, Department of Biostatistics, Temple, TX; A.B. Bonner, Texas A&M University, Dell Children’s Hospital, Austin, TX. Objective: Continuous-chest-compression CPR (CCC-CPR) has been advocated as an alternative to standard CPR (STDCPR). Studies have shown a degradation of adequate compressions with CCC-CPR after 2 minutes when performed by young, healthy medical students. It is unknown how fatigue affects elderly rescuers’ ability to maintain an adequate compression rate and depth throughout an average EMS response time. The specific aim of this study was to compare the effects of fatigue on the performance of CCC-CPR and STD-CPR by elderly rescuers in a manikin model. Methods: In this prospective, randomized crossover study 17 retired doctors and nurses, age 60 to 84 years, performed both CCC-CPR and STD-CPR on a manikin model for 9 minutes each. Subjects were randomized to their first method and tests were separated by at least 2 days. The primary endpoint was the number of adequate chest compressions (at least 38 mm of compression depth) delivered per minute. Secondary endpoints were total compressions, compression rate and the number of breaks taken for rest. The students’ performance was evaluated based on Laerdal Skillreporter Resusci Anne recordings. Primary and secondary endpoints were analyzed using generalized linear mixed (GLIMMIX) model for counting data. Results: Overall, more adequate compressions per minute were delivered in STD-CPR than CCCCPR (p⬍0.0001) over the 9 minute period. There was no difference in the number of adequate compressions in the first minute. However, the group performing STD-CPR delivered significantly more adequate chest compressions in minutes 2 – 9 (p ⬍ 0.05). The total number of compressions delivered was significantly greater in the CCC-CPR than STD-CPR group when considering the entire resuscitation and each minute individually. There were no differences in compression rates or

324 number of breaks between groups. Conclusions: Although CCC-CPR resulted in a greater number of overall compressions than STD-CPR, STD-CPR resulted in a greater number of adequate compressions in all but the first minute of resuscitation. These differences are presumably due to fatigue.

e PERFORMANCE CHARACTERISTICS OF ENDOVASCULAR COOLING DEVICES FOR INDUCING HYPOTHERMIA AFTER CARDIAC ARREST. R. Silbergleit, P. Scott, X. Wang, Department of Emergency Medicine, University of Michigan, Ann Arbor, MI. Objective: Resuscitative hypothermia for comatose survivors of cardiac arrest improves recovery, and is now recommended in ILCOR and AHA emergency cardiac care guidelines. Endovascular cooling devices are more accurate and rapid than traditional surface cooling. Our objective is to objectively describe the performance characteristics and features of the 2 currently marketed endovascular cooling devices; Alsius (AL) and Innercool (IN). Methods: Institutional animal use approval was obtained. 2 human-sized 65kg swine were cooled from 37°C to 33°C, maintained at 33°C for 1 hr, then rewarmed over 3 hrs on 2 occasions spaced a week apart. In a crossover design, each animal was cooled once by each device. Animals were anesthetized with propofol/fentanyl. Index temperature was measured in the esophagus. 14 physician and nurse evaluators from 5 departments qualitatively scored features of the devices. Performance was analyzed by area under the curve (AUC) of mean temperature versus time, and mean time to target temperature (TTT). Continuous variables were compared by Kaplan-Meier and t-test analysis. Results: Both devices worked quickly and maintained tight control of core temperature. The IN device cooled more rapidly than the AL device (AUC 74 min*deg v. 113 min*deg, TTT 77 min v. 98 min). During maintenance the maximal deviation from target temperature for either device was 0.2°C. Evaluators preferred the AL device for ease of placement, catheter size, console design/ sturdiness, and ease of use. Evaluators preferred the IN device for catheter design/sturdiness. There was no difference in overall preference, and cooling performance was deemed most important among a list of features. Conclusions: Endovascular devices cool human-sized pigs to a target temperature of 33°C within 45-120 minutes. The IN device cools 25-50% more quickly than the AL device. Evaluators preferred the AL over the IN on twice as many

The Journal of Emergency Medicine device characteristics, but rated cooling performance as the most important feature.

e PROTECTIVE HEAD COOLING DURING CARDIAC ARREST AND CPR: THE ORIGINAL ANIMAL STUDIES. E. Brader, Mercy Hospital of Pittsburgh, Pittsburgh, PA; D. Jehle, State University of New York at Buffalo, Department of Emergency Medicine, Buffalo, NY; P. Safar, Resuscitation Research Center University of Pittsburgh Medical Center, Pittsburgh, PA. Introduction: Prolonged standard CPR cannot reliably sustain brain viability during cardiac arrest. Adjuncts to standard CPR that can be applied in the prehospital setting are needed that are applicable by first responders as well as professional personnel. The preliminary dog study demonstrated that surface cooling of the head during arrest and CPR can achieve protective levels of brain surface hypothermia within 10 minutes and therapeutic mild hypothermia reperfusion upon ROSC via thermal re-equilibration. We hypothesize that protective head cooling during cardiac arrest and CPR improves neurological outcome. Methods: Twelve dogs under light ketamine-halothane-nitrous oxide anesthesia were arrested by transthoracic fibrillation. The treated group consisted of six dogs whose shaven heads were moistened with saline and packed in ice immediately after confirmation of ventricular fibrillation. Six