Murphy, Ryan A.

Background: Bystander CPR (BCPR) strongly influences survival from OHCA yet is provided in a minority of cases. The AHA has promulgated guidelines on provision of pre-arrival Hands-Only dispatcher-assisted telephone CPR (TCPR) instructions to increase the proportion of arrests receiving early BCPR; however, the impact of those guidelines is unknown. Objective: Evaluate the impact of implementing the TCPR guidelines on: recognition of OHCA by 911 dispatchers, time from call receipt to start of TCPR instructions, time to first chest compression (CC), prehospital ROSC, survival, and favorable neuro outcome (FNO). Methods: Dispatch audio records of OHCA in 3 large dispatch centers in Arizona (10/10-3/13) were reviewed using a standardized time-stamp methodology. Data were entered into a structured TCPR database linked to EMS and hospital outcome data. Intervention: Implementation of a 3.5-hour staff training and a guideline-based change in dispatch protocol. Results: There were 860 pre-implementation (P1) and 799 post-implementation (P2) cases. A total of 1265 cases met inclusion criteria. Outcome data collection and linkage is ongoing: ROSC, survival and neuro outcomes were available in 26%, 24% and 22% of cases, respectively. The proportion of cases receiving TCPR increased: P1 (28.7%); P2 (49.9%, p<0.001). Median time to beginning TCPR instructions decreased significantly: P1 (153 sec); P2 (129 sec, p<0.001) as did median time to first CC: P1 (198 sec); P2 (162 sec, p<0.001). Outcomes - see Table. Conclusion: The implementation of the AHA pre-arrival TCPR guidelines was associated with a significant improvement in the time-to-CPR instructions and time-to-first CCs and rate of provision of telephone-assisted bystander CPR. This small, preliminary analysis of prehospital ROSC, survival, and FNO revealed higher, but statistically non-significant, rates after the interventions.

Background: In the simulation setting, chest compression (CC) quality is reduced when out-of-hospital cardiac arrest “patients” are prepared for transport (i.e. packaged and moved to ambulance). It is unknown whether use of real-time audiovisual CPR feedback (RTAVF) affects manual CC quality when the patient is prepared for transport during actual out-of-hospital resuscitations. We tested the hypothesis that CC quality during patient transfer would be better when using RTAVF. Methods: CC quality was monitored at two EMS agencies using an E Series monitor/defibrillator with CC sensing capability (ZOLL Medical) during the treatment of consecutive out-of-hospital cardiac arrest patients who received CC on scene and were transported with ongoing CC. Data were collected during study phases; P1: RTAVF disabled, P2: RTAVF enabled following scenario-based training. Student’s t-test and Wilcoxon-Mann Whitney tests were used to compare CC quality in P1 vs. P2 during early scene and late scene treatment. Late scene was defined as the 3 minutes prior to transport (when packaging and transfer to the ambulance occurs) and early scene was all prior minutes at the scene. Results: 211 cardiac arrest cases were included: mean age 64±15 yrs, 67% male, 8% survival to hospital discharge. The Table shows that CC quality was superior during both early scene and late scene treatment in P2, when RTAVF was enabled, vs. P1, when RTAVF was disabled. Conclusion: CC quality, particularly the CC fraction, declines when a patient is packaged for transport and moved to the ambulance. While this decline is not prevented by RTAVF, CC quality during the late scene period is significantly better when using RTAVF. Further study is required to determine the impact of this improvement on outcomes.

Background: Quantitative End-Tidal CO2 (PETCO2) measurement during cardiac arrest is recommended for monitoring the CPR quality to detect ROSC. While low ETC02 can reflect suboptimal CPR quality and increases in ETC02 are often associated with ROSC the significance of high values of PETCO2 without ROSC remain unclear. Objectives: To describe the population of OHCA victims with high PETCO2 (>50 mm Hg) during ongoing resuscitation including demographics, rhythm characteristics, occurrence of ROSC, the later occurrence of field termination of resuscitation and the presumed etiology. Methods: An observational analysis of adult OHCAs with available PETCO2 data occurring between Oct 2010 and Nov 2014 at two sites involved in the Save Hearts in Arizona Registry and Education (SHARE) quality improvement program. CPR and PETCO2 data were recorded using ZOLL E and X Series EMS monitors. PETCO2 is reported as the mean value for each minute. The cardiac rhythm and the presence of ROSC were determined for each minute using EMS provider reports, vital signs, ECG, and accelerometer data. The first recorded minute of PETCO2 and minutes with ROSC were excluded. Results: Study population included 654 OHCAs with PETCO2 data, 96 cases (58% male, age median 65 (IQR 54-75)) with at least 1 min of high PETCO2 in the absence of ROSC were identified. Of these, 31 (32%) had ROSC at least once during their resuscitation. Cases were of presumed cardiac etiology in 81 (84%), while 12% and 4% had presumed respiratory and other etiologies, respectively. A total of 322 minutes of PETCO2 >50 mm Hg in the absence of ROSC were identified. The mean PETC02 value was 67 (IQR 54-75). Of these 296 minutes (92%) occurred during PEA. Despite high PETCO2, resuscitation was terminated in the field in 21 (22%) patients. Only one subject survived to hospital discharge. Conclusions: In this observational study, high PETCO2 was frequently found during resuscitation without ROSC and PEA was the most common cardiac rhythm. Further study is warranted to determine the significance and possible reasons for this finding.

Background: Previous studies have described modest correlation between end-tidal CO 2 (ETCO 2 ) and CPR quality during resuscitation of cardiac arrest patients, but it is unclear whether ETCO 2 alone can indicate CPR quality. The present study investigated whether ETCO 2 adequately identifies the quality of CPR provided during out-of-hospital cardiac resuscitation. Methods: ETCO 2 was monitored with side-stream CO 2 (Philips/Respironics) and CPR quality measured with an accelerometer-based system (E Series, ZOLL Medical) during the treatment of consecutive adult OHCA patients with presumed cardiac etiology by 2 EMS agencies in the Arizona SHARE QI Program between 10/08-06/13. Minute-by-minute ETCO 2 and CPR quality were extracted. ETCO 2 values were log transformation to achieve approximate normality. Linear mixed effect models were fitted to use (transformed) ETCO 2 level to predict four CPR variables: chest compression (CC) depth, CC rate, CC release velocity (CCRV), and ventilation rate (VR). A random intercept for each case was included and a spatial power covariance structure assumed for measurements over time. Results: 230 subjects (median age 69 yrs, 69% male) with 1581 minutes of data were studied. Transformed ETCO 2 was significant for CC depth (p< 0.0001), CCRV (p=0.003) and VR (p<0.0001), but only explained 3.7%, 2.7%, and 10.0% of the total variance for these variables, respectively. Transformed ETCO 2 was not a significant predictor for CC rate (p=0.89). The Figure illustrates the overlap in CC depth over quartiles of ETCO 2 , demonstrating that any specific ETCO 2 level could be found over a wide range of CC depths. Conclusion: In this secondary analysis, ETCO 2 was not an independent indicator of CC rate but was a weak predictor for CC depth, CCRV and VR. These findings suggest that ETCO 2 may be not be an adequate substitute for CPR quality monitoring. Future studies should investigate how ETCO 2 and CPR quality monitoring can be used in conjunction to optimize CPR.

Background: Abnormal breathing, or “gasping,” frequently occurs during cardiac arrest and has been associated with increased survival. During 9-1-1 calls, early recognition of gasping may allow dispatchers to identify OHCA and to start CPR instructions promptly. Objective: To characterize lay rescuers’ descriptions of abnormal breathing during OHCA. Methods: 9-1-1 audio recordings of 4,279 confirmed OHCAs (10/10-7/14) in Arizona were reviewed by program personnel. Terms used by lay rescuers to describe victims’ breathing were recorded in a structured database. Results: Abnormal breathing (as opposed to “not breathing”) was described in 542/4279 (13%) calls. There were 623 verbal descriptions. A total of 50 different terms were used. However, the top 8 accounted for 83% and the remaining 42 descriptions (“Other”) comprised only 17% of all terms used. “Gasping” was the most commonly used term (30%; 187/623), followed by “snoring” (15%; 95/623; Figure). Conclusion: Lay rescuers used a wide variety of terms to describe abnormal breathing in documented OHCA. However, 8 terms accounted for 83% of descriptions. Familiarizing 9-1-1 telecommunicators with the most commonly used terms may improve the accuracy of recognition and hasten the identification of OHCA.