Stolz, Uwe

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: CPR quality is closely linked to outcome in cardiac arrest. The AHA 2010 Guidelines recommend monitoring CPR quality performed by healthcare providers both inside and outside the hospital. However, most EDs currently do not monitor CPR quality. The goal of the present investigation was to assess the quality of CPR performed in an urban ED and determine the influence of training and real-time audiovisual feedback (RTAVF) on CPR quality and patient outcome. Methods: CPR quality was monitored using an R Series defibrillator (ZOLL Medical) during the treatment of adult cardiac resuscitation attempts. During phase 1 (P1; 11/2010-11/2012), real-time audiovisual chest compression feedback was disabled. During phase 2 (P2; 11/2012-3/2013), clinicians underwent a 60 minute didactic/hands-on CPR training session after which the RTAVF and the ECG artifact filtering feature were enabled. CPR quality data (fraction, depth, rate, release, peri-shock pause) were reviewed using Code Review software (ZOLL Medical). Student’s t-test and Wilcoxon-signed rank test were employed. Results: A total of 44 OHCA patients were treated in P1 (mean age 57±18 yrs, 59% male) and 24 in Phase 2 (mean age 63±15 yrs, 88% male). The majority of patients (89% P1; 96% P2) suffered prehospital arrest and were transported to the ED. Chest compression (CC) depth increased from 1.8±0.5 inches in P1 to 2.3±0.4 in P2 (p<0.001), with the percentage of compressions exceeding 2 inches more than doubling from 36% in P1 to 79% in P2 (p<0.001). CC release velocity increased from 1.25±0.36 inch/sec in P1 to 1.69±0.28 in P2 (p<0.001). No significant differences were identified in CC rate (125±12 cpm P1 vs. 121±15 cpm P2, p=0.3) or CC fraction (82% P1 vs. 87% P2, p=0.1). Pre-shock pause (11.5±10.4 sec P1 vs. 8.0±6.2 P2, p=0.4) and post-shock pause (5.2±3.4 sec vs. 3.8±0.6, p=0.9) were statistically similar in P1 and P2. Conclusion: The bundle of real time audiovisual CPR feedback and training were associated with an improvement in chest compression depth and recoil and closer adherence to guidelines for CPR quality in this large urban ED.

Background: During CPR in animals, chest compressions (CC) may produce passive volumes large enough to provide adequate ventilation. In humans, this mechanism may explain why continuous CCs have been associated with improved survival. We quantified the volume of passive ventilation during emergency department (ED) CCs to determine if compression-only CPR (COCPR) provides clinically significant gas exchange during resuscitation. Methods: In an urban ED, continuous flow and volume of air exhaled through an endotracheal tube were measured during the CC phase of manual CPR (between ventilations) with NICO monitors (Philip/Respironics) and recorded using LabView (National Instruments). Gas exchange with CC was quantified using Matlab (Mathworks) as the area under the flow curve (figure). CC quality was measured using accelerometer-based technology (R Series, ZOLL Medical). Results: Eight patients (6 male) aged 37-83 yrs [median age 51 yr (IQR 43-56)] who suffered out-of-hospital cardiac arrest (CA) and were transported and treated with CC in the ED were included. A total of 548 CCs [median depth 1.89 in (IQR=1.66, 2.29), median rate 128 CC/min (IQR=122-134) were analyzed over 30 min of CPR. Median tidal volume per CC was 17.3 mL (IQR=5.9-22.4). This was considerably less than measured dead space in all patients (median 118mL, IQR=93-143), regardless of CC depth. The figure illustrates a typical tracing in which ventilation volume dwarfs any passive ventilation occurring with CC. Conclusion: Late in CA, passive ventilation occurring during CCs appears to produce considerably less gas exchange than calculated dead space. The effectiveness of passive ventilation during early stages of CPR, when chest and lung compliance are greater, remains unknown. However, these findings suggest that the benefits of COCPR strategies may be related to reliably higher CC fraction and/or prevention of the negative effects of hyperventilation rather than from any passive ventilation.

Background: The 2010 AHA Guidelines state rescuers should perform chest compressions (CCs) of at least 2 inches in depth for adult cardiac arrest patients. Although the pediatric guidelines recommend adjustment of CC depth based upon anteroposterior chest dimension, there is no such recommendation for adults. Purpose: To determine 1) whether prehospital providers intuitively vary CC depth in adults according to patient size and 2) whether implementation of real-time audiovisual CPR feedback (RTAVF) impacts weight/CC depth variation. Methods: CC quality data were prospectively collected prior to (9/08-4/10; Pre-feedback) and after (5/10-12/10; Post-feedback) implementation of an RTAVF system (ZOLL Medical, Chelmsford MA) from 3 EMS agencies. The RTAVF includes a visual display of absolute CC depth and gives audio prompts when depth is outside of the Guideline-recommended range. Among 363 cases of adult, non-traumatic out-of-hospital cardiac arrest (OHCA), body weight was estimated by EMS in 249 patients (study group; 66%). CPR quality data were available for all cases via code review software. Results: 168 Pre-feedback and 81 Post-feedback study group cases (mean 64±16 years, 68% male). Mean estimated body weight was 201 lbs (quartiles 161, 231; range 70-451) and was not different between groups. CC depth increased significantly with RTAVF use (Pre-feedback = 1.77, 95% confidence interval [CI]:1.71-1.83 in.; Post-feedback = 2.10, CI: 2.04-2.15 in.; p<0.001). CC depth did not vary significantly by patient gender or age (p>0.4). Multivariate linear regression (r 2 =0.23, p<0.001 for model) revealed a significant increase in CC depth with estimated weight in both periods (0.07in/50lbs, p<0.001) after controlling for the presence of RTAVF. RTAVF was not an effect-modifier of the relationship between estimated weight and CC depth (p-value for interaction term=0.4). Conclusion: Although not specifically recommended in the 2010 AHA Guidelines for adults, rescuers may instinctively and/or intentionally adjust CC depth according to patient size. In this setting, weight/CC depth adjustments occurred both without and with real-time feedback. Follow-up studies are needed to determine the potential effect of size-adjusted CC depth on patient outcome.

BACKGROUND: For sudden collapse from out-of-hospital cardiac arrest (OHCA) in adults, bystander chest compression-only CPR (COCPR) results in equivalent or better survival compared with conventional CPR with rescue breathing. However, patients who arrest from a non-cardiac cause may also receive COCPR even though rescue breathing might benefit them. We sought to determine whether lay rescuers appropriately provided COCPR or conventional CPR depending on the suspected etiology of OHCA. METHODS: Analysis of a statewide, Utstein-style registry of adult OHCA during a large-scale campaign endorsing COCPR for adults who suddenly collapse. The relationship between bystander CPR (both COCPR and conventional CPR), presumed arrest etiology, and survival to hospital discharge were evaluated. Means and 95% confidence intervals (CI) were calculated. FINDINGS: A total of 7,652 adult OHCAs not witnessed by EMS were analyzed from 10/04 to 09/10. After exclusion of non-lay bystanders and arrests in medical facilities, presumed cardiac etiology and non-cardiac etiology OHCA totaled 4,913 and 1,202, respectively. The presumed specific non-cardiac etiologies were non-cardiopulmonary (e.g. overdose, suicide, subarachnoid hemorrhage) (57%), trauma (27%), and respiratory (16%). All-rhythm survival was 7.0% (CI: 6.3 - 7.8) for cardiac etiologies and 3.3% (CI: 2.3 - 4.3) for non-cardiac (p<0.001). Bystander CPR was provided for 33% (CI: 31.4 - 34.1) of victims with presumed cardiac causes versus 28% (CI: 25.6 - 30.7) for non-cardiac causes (p=0.002). Presumed respiratory causes of OHCA had a much lower proportion of COCPR (8.3%, CI: 4.4 - 12.2) than cardiac causes (18.0%, CI: 16.9 - 19.1, p<0.001). Survival for non-cardiac cases was: 4.4% (CI 0.9 - 7.8) for conventional CPR, 3.5% (CI: 0.9 - 6.0) for COCPR, and 3.1% (CI: 2.0 - 4.3) for no CPR (p = 0.66). CONCLUSIONS: In the setting of a large-scale, statewide public health campaign endorsing lay rescuer COCPR for adults who suddenly collapse and are not breathing normally, bystanders were much less likely to perform COCPR on OHCA victims who might benefit from rescue breathing. Furthermore, when COCPR was performed on presumed non-cardiac cause arrest victims, there was no demonstrable negative impact on survival.

Objective: The 2010 AHA Guidelines stress the need for minimally interrupted, high quality CPR. We performed a prospective, before/after trial to determine if real-time audiovisual feedback (RTAVF) along with scenario-based training (SBT) would 1) achieve the 2010 CPR targets and 2) improve survival from OHCA. Methods: Data obtained from EMS care forms and defibrillators (E Series, ZOLL) from 2 EMS agencies (population base-500,000). Phase 1 (P1, before): 18 months of baseline data with the RTAVF mode disabled (9/08-3/10). Interventions: 1) Guideline-based SBT of ~450 EMTs, 2) RTAVF enabled, 3) EMT post-code debriefings. Phase 2 (P2, after): 8 months following implementation of interventions (5/10-12/10). For univariate analyses we used Fisher's exact test (proportions), t-test (means) or Kruskal-Wallis test (medians). To estimate odds ratios for survival to hospital discharge we used multivariable logistic regression and assessed final model diagnostics, fit, and discrimination. Results: The final analysis included 284 adult OHCAs (P1-176, P2-108). Mean age 65.4 years (SD ± 15.3) with 66.6% males. Quality measures improved significantly from P1 to P2: Median (Interquartile range) chest compression (CC) rate-121 CC/min (109-135) to 101 CC/min (100-106), p <0.001; CC depth-1.73 in. (1.42-1.97) to 2.09 in. (1.92-2.3), p <0.001; CC fraction-66.5% (59.3-75.9%) to 84.0% (77.8-88.7%), p <0.001. All-rhythms survival increased significantly (p=0.034) from P1 to P2 (18/176, 10.2% vs. 23/108, 19.4%), an absolute survival increase of 9.2% (95% CI: 0.5%-17.9%). Crude odds ratio for survival for P2 vs. P1 was 2.1 (95% CI: 1.1-4.2) and adjusted odds ratio was 5.8 (95% CI: 1.8-18.9), after controlling for confounders including age, sex, location, witnessed arrest, initial rhythm, and therapeutic hypothermia. Survival for arrests with a shockable rhythm was 27.7% (18/65) for P1 and 53.9% (14/26) for P2 (p=0.028). Conclusion: RTAVF combined with SBT was associated with a significant improvement in the proportion of compressions meeting the 2010 AHA Guidelines. This intervention was associated with a 90% relative increase in overall survival. We believe this is the first report to show an improvement in OHCA survival by achieving the 2010 AHA CPR Guidelines.

Background: Bystander CPR (BCPR) increases survival from OHCA yet is provided in a minority of cases. The AHA has promulgated guidelines on the provision of pre-arrival Telephone CPR (TCPR) instructions and measurement to increase the proportion of BCPR; however, the impact of those guidelines on survival is unknown. Objective: To describe the impact of a comprehensive bundle of 9-1-1 TCPR protocol, training, data collection, and feedback on BCPR and survival from OHCA across the state of Arizona. Methods: 9-1-1 audio recordings of confirmed OHCAs and suspected OHCAs (10/2010-6/2013) in 7 large 9-1-1 centers were reviewed using a standardized time-stamp methodology linked with EMS and hospital process and outcome data. There were 2343 pre-implementation cases (P1) and 2291 cases post-implementation of a bundle of care (P2) that included staff training and guideline-based protocol changes, data collection and feedback to providers. Univariate and multivariable analyses were used to assess outcomes between P1 and P2. Results: There were 2532 OHCAs [1232 P1, 1300 P2; 64% male, median age 62 (IQR: 47-74)]. 83% of cases were identified in P1 compared with 89% in P2 (p<0.001). The rate of telephone-assisted BCPR went from 44% in P1 to 62% in P2 (p<0.001). Time to beginning TCPR instructions decreased from a median of 144 sec (P1) to 126 in P2 (p<0.001). Time to first chest compression also decreased (P1: 178; P2: 155; p<0.001). Outcome data are currently available for 64% of confirmed OHCAs (1630 patient outcomes with 1619 neuro outcomes). Survival was significantly higher in P2 (11.2%) compared to P1 (7.9%; p=0.023), as was good neuro outcome (CPC-1 or 2: 7.7% P2 vs. 4.8% P1 p=0.018). After adjusting for witnessed arrest, shockable rhythms, age, and sex, both survival and good neuro outcome were still significantly higher in P2 vs. P1 [adjusted odds ratios: survival = 1.5 (95% 1.1-2.1); good neuro outcome = 1.7 (95% 1.1-2.6)]. Conclusion: The implementation of a comprehensive statewide TCPR bundle was associated with significant improvements in the rates of telephone-assisted BCPR, survival and good neurologic outcome after OHCA.