Hypes, Cameron

Background: High quality manual chest compressions (CC) can be achieved on scene during resuscitation of cardiac arrest patients, but manual CC quality can deteriorate during patient extrication and transport. The purpose of this study was to describe the effect on CC quality of an integrated manual/mechanical chest compression protocol developed to maintain CC quality and patient/provider safety throughout resuscitation. Methods: CC quality was monitored using a monitor with accelerometer-based CC sensing (E Series/X Series, ZOLL Medical) during the treatment of consecutive out-of-hospital cardiac arrest patients between 3/1/2013-4/30/2015. The EMS agency performed manual CC guided by real-time audiovisual feedback on scene but deployed the AutoPulse load-distributing band CC device (LDB, ZOLL Medical) in a choreographed manner for extrication and transport. The LDB was also placed prophylactically on patients after ROSC. Descriptive statistics are reported as median (IQR). Results: A total of 71 OHCA patients were treated (median age 58 yrs, 66 % male) of which 39 received only manual CC and 32 received both manual and LDB CCs (22 with LDB deployed during ongoing manual CC and 10 with LDB placed after ROSC). With real-time CC feedback, high quality CCs were performed [depth 2.38 in (2.17-2.64), rate 100.3 cpm (99.2-102.5), CC fraction 87.0% (83.8-89.5)]. For patients requiring transport, the LDB was started after 14.2 min (11.6-19.2) of manual CC and was placed with minimal interruptions- total of 27.5 sec (23-42) pause time in 2 minutes prior to LDB deployment. During transport, CC fraction remained high (91.7%; 89.3-95.4) with use of LDB. Seven of 10 patients prophylactically placed on the LDB rearrested, 3 rearrested during transport. Conclusion: A choreographed and rehearsed integrated chest compression protocol featuring both manual and mechanical compressions, allows for high quality resuscitation with minimal compression interruptions. Placement of a mechanical device on patients after ROSC may be beneficial as over two-thirds of patients in this study rearrested, one-third of which occurred during transport when delivery of manual compressions is difficult and potentially dangerous.

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.