External artifacts by advanced life support providers misleading automated external defibrillators

In-hospital cardiac arrest rhythm analysis by anesthesiologists: a diagnostic performance study

PURPOSE

In-hospital cardiac arrest is associated with high morbidity and mortality, with an overall survival rate at one year of approximately 13%. The first cardiac rhythm is often analyzed by anesthesiologist-intensivists. We aimed to determine the diagnostic performance of anesthesiologist-intensivists when distinguishing between shockable and nonshockable rhythms.

METHODS

We conducted a simulation-based, multicentre, prospective, observational study between May 2019 and March 2020. The responses of the participants were used to calculate individual sensitivity (defined as the proportion of decisions to shock for shockable rhythms) and individual specificity (defined as the proportion of decisions not to shock for nonshockable rhythms). The main outcome measure was the overall diagnostic performance, defined as the overall sensitivity and specificity. Secondary outcome measures were the sensitivity and specificity of participants' decisions for each type of cardiac arrest rhythm and their decision-making times.

RESULTS

Among the 267 physicians contacted, 179 (67%) completed the test. The median [interquartile range (IQR)] overall sensitivity was 88 [79-95]% and the median overall specificity was 86 [77-92]%. Among shockable rhythms, the median [IQR] sensitivity was 100 [100-100]% for ventricular tachycardia (VT), 100 [100-100]% for coarse ventricular fibrillation (VF), and 60 [20-100]% for fine VF. The median [IQR] specificities for nonshockable rhythms were 93 [86-100]% for asystole and 83 [72-86]% for pulseless electrical activity. The median decision times ranged from 2.0 to 3.5 sec.

CONCLUSION

Anesthesiologist-intensivists were quickly and effectively able to analyze rhythms in this simulation-based study. Participants' sensitivity in deciding to deliver shocks for VT and coarse VF was excellent, while specificity of their decisions for pulseless electrical activity was insufficient.

The Effect of Transport Time Interval on Neurological Recovery after Out-of-Hospital Cardiac Arrest in Patients without a Prehospital Return of Spontaneous Circulation

BACKGROUND

Longer transport adversely affects outcomes in out-of-hospital cardiac arrest (OHCA) patients who do not return to spontaneous circulation (ROSC). The aim of this study was to determine the association between the transport time interval (TTI) and neurological outcomes in OHCA patients without ROSC.

METHODS

We analyzed adult OHCA patients with presumed cardiac etiology and without prehospital ROSC from 2012 to 2015. The study population was divided into 2 groups according to STI (short STI [1-5 minutes] and long STI [≥ 6 minutes]). The primary exposure was TTI, which was categorized as short (1-5 minutes), intermediate (6-10 minutes), or long (≥ 11 minutes). The primary outcome was a good neurological recovery at discharge. Multiple logistic regression analysis was used in each STI group.

RESULTS

Among 57,822 patients, 23,043 (40%), 20,985 (36%), and 13,794 (24%) were classified as short, intermediate, and long TTI group. A good neurological recovery occurred in 1.0%, 0.6%, and 0.3% of the patients in the short, intermediate and long TTI group, respectively. Among 12,652 patients with short STI, a good neurological recovery occurred in 2.2%, 1.0%, and 0.4% of the patients in the short, intermediate and long TTI group, respectively. Among 45,570 patients with long STI, a good neurological recovery occurred in 0.7%, 0.5%, and 0.3% of the patients in the short, intermediate and long TTI group, respectively. When short TTI was used as a reference, the adjusted odds ratios (AOR) of TTI for good neurological recovery was different between short STI group and long STI group (AOR [95% confidence interval, 0.46 [0.32-0.67] vs. 0.72 [0.59-0.89], respectively, for intermediate TTI and 0.31 [0.17-0.55] vs. 0.49 [0.37-0.65], respectively, for long TTI).

CONCLUSION

A longer TTI adversely affected the likelihood of a good neurological recovery in OHCA patients without prehospital ROSC. This negative effect was more prominent in short STI group.

Neurological Favorable Outcomes Associated with EMS Compliance and On-Scene Resuscitation Time Protocol

PURPOSE

Korean national emergency care protocol for EMS providers recommends a minimum of 5 minutes of on-scene resuscitation before transport to hospital in cases of Out-of-Hospital Cardiac Arrest (OHCA). We compared survival outcome of OHCA patients according to scene time interval (STI)-protocol compliance of EMS.

METHODS

EMS treated adult OHCAs with presumed cardiac etiology during a two-year period were analyzed. Non-compliance was defined as hospital transport with STI less than 6 minutes without return of spontaneous circulation (ROSC) on scene. Propensity score for compliance with protocol was calculated and based on the calculated propensity score, 1:1 matching was performed between compliance and non-compliance group. Univariate analysis as well as multivariable logistic model was used to evaluate the effect of compliance to survival outcome.

RESULTS

Among a total of 28,100 OHCAs, EMS transported 7,026 (25.0%) cardiac arrests without ROSC on the scene with an STI less than 6 minutes. A total of 6,854 cases in each group were matched using propensity score matching. Overall survival to discharge rate did not differ in both groups (4.6% for compliance group vs. 4.5 for non-compliance group, p = 0.78). Adjusted odds ratio of compliance for survival to discharge were 1.12 (95% CI 0.92-1.36). More patients with favorable neurological outcome was shown in compliance group (2.5% vs. 1.7%, p < 0.01) and adjusted odds ratio was 1.91 (95% CI 1.42-2.59).

CONCLUSIONS

Although survival to discharge rate did not differ for patient with EMS non-compliance with STI protocol, lesser patients survived with favorable neurological outcomes when EMS did not stay for sufficient time on scene in OHCA before transport.

Sensitivity and specificity of two different automated external defibrillators

AIM

The aim was to investigate the clinical performance of two different types of automated external defibrillators (AEDs).

METHODS

Three investigators reviewed 2938 rhythm analyses performed by AEDs in 240 consecutive patients (median age 72, q1-q3=62-83) who had suffered cardiac arrest between January 2011 and March 2015. Two different AEDs were used (AED A n=105, AED B n=135) in-hospital (n=91) and out-of-hospital (n=149).

RESULTS

Among 194 shockable rhythms, 17 (8.8%) were not recognized by AED A, while AED B recognized 100% (n=135) of shockable episodes (sensitivity 91.2 vs 100%, p<0.01). In AED A, 8 (47.1%) of these episodes were judged to be algorithm errors while 9 (52.9%) were caused by external artifacts. Among 1039 non-shockable rhythms, AED A recommended shock in 11 (1.0%), while AED B recommended shock in 63 (4.1%) of 1523 episodes (specificity 98.9 vs 95.9, p<0.001). In AED A, 2 (18.2%) of these episodes were judged to be algorithm errors (AED B, n=40, 63.5%), while 9 (81.8%) were caused by external artifacts (AED B, n=23, 36.5%).

CONCLUSIONS

There were significant differences in sensitivity and specificity between the two different AEDs. A higher sensitivity of AED B was associated with a lower specificity while a higher specificity of AED A was associated with a lower sensitivity. AED manufacturers should work to improve the algorithms. In addition, AED use should always be reviewed with a routine for giving feedback, and medical personnel should be aware of the specific strengths and shortcomings of the device they are using.