Protocol for a cluster randomised controlled feasibility study of Prehospital Optimal Shock Energy for Defibrillation (POSED)

AIMS

The Prehospital Optimal Shock Energy for Defibrillation (POSED) study will assess the feasibility of conducting a cluster randomised controlled study of clinical effectiveness in UK ambulance services to identify the optimal shock energy for defibrillation.

METHODS

POSED is a pragmatic, allocation concealed, open label, cluster randomised, controlled feasibility study. Defibrillators within a single UK ambulance service will be randomised in an equal ratio to deliver one of three shock strategies 120-150-200 J, 150-200-200 J, 200-200-200 J. Consecutive adults (≥18 years) presenting with out of hospital cardiac arrest requiring defibrillation will be eligible. The study plans to enrol 90 patients (30 in each group). Patients (or their relatives for non-survivors) will be informed about trial participation after the initial emergency has resolved. Survivors will be invited to consent to participate in follow-up (i.e., at 30 days or discharge).The primary feasibility outcome is the proportion of eligible patients who receive the randomised study intervention. Secondary feasibility outcomes will include recruitment rate, adherence to allocated treatment and data completeness. Clinical outcomes will include Return of an Organised Rhythm (ROOR) at 2 minutes post-shock, refibrillation rate, Return of Spontaneous Circulation (ROSC) at hospital handover, survival and neurological outcome at 30 days.

CONCLUSION

The POSED study will assess the feasibility of a large-scale trial and explore opportunities to optimise the trial protocol.Trial registration: ISRCTN16327029.

Mechanical life support algorithm developed by simulation for inpatient emergency management of recipients of implantable left ventricular assist devices

Background

Published guidance concerning emergency management of left ventricular assist device (LVAD) recipients is both limited and lacking in consensus which increases the risk of delayed and/or inappropriate actions.

Methods

In our specialist tertiary referral centre we developed, by iteration, a novel in-hospital resuscitation algorithm for LVAD emergencies which we validated through simulation and assessment of our multi-disciplinary team. A Mechanical Life Support course was established to provide theoretical and practical education combined with simulation to consolidate knowledge and confidence in algorithm use. We assessed these measures using confidence scoring, a key performance indicator (the time taken to restart LVAD function) and a multiple-choice question (MCQ) examination.

Results

The mean baseline staff confidence score in management of LVAD emergencies was 2.4 ± 1.2 out of a maximum of 5 (n = 29). After training with simulation, mean confidence score increased to 3.5 ± 0.8 (n = 13).

Clinical personnel who were provided with the novel resuscitation algorithm were able to reduce time taken to restart LVAD function from a mean value of 49 ± 8.2 seconds (pre-training) to 20.4 ± 5 seconds (post-training) (n = 42, p < 0.0001).

The Mechanical Life Support course increased mean confidence from 2.5 ± 1.2 to 4 ± 0.6 (n = 44, p < 0.0001) and mean MCQ score from 18.7 ± 3.4 to 22.8 ± 2.6, out of a maximum of 28 (n = 44, p < 0.0001).

Conclusion

We present a simplified LVAD Advanced Life Support algorithm to aid the crucial first minutes of resuscitation where basic interventions are likely to be critical in assuring good patient outcomes.

CHA2DS2-VASC score predicts coronary artery disease progression and mortality after ventricular arrhythmia in patients with implantable cardioverter-defibrillator

Aim

The CHA₂DS₂-VASC score has expanded its use beyond the initial purpose of predicting the risk of stroke in patients with atrial fibrillation. We aimed to investigate the value of the CHA₂DS₂-VASC score as a risk assessment tool to predict relevant coronary artery disease (CAD) leading to percutaneous coronary intervention (PCI), and all-cause mortality after detected ventricular arrhythmia (VA) in patients with an Implantable Cardioverter-Defibrillator (ICD).

Methods

A total of 183 ICD-patients who underwent coronary angiography after VA were included and classified according to their CHA₂DS₂-VASC score in a low(1-3), intermediate(4-5) and high(6-8) score group. We evaluated the predictive value of CHA₂DS₂-VASC score for the presence of relevant CAD leading to percutaneous coronary intervention (PCI), as well as late all-cause mortality.

Results

A total of 60 patients (32.8%) had significant CAD and underwent successful PCI. After adjustment for relevant parameters such as ischemic cardiomyopathy, angina pectoris, left ventricular ejection fraction, CHA₂DS₂-VASC score remained the only independent predictor of CAD leading to PCI [HR 1.73 (1.07–2.80)]. The Area under curve was 0.64 (0.56–72, p = 0.002). Kaplan-Meier analysis and log-rank showed an increased three-year mortality of ICD-patients with an intermediate or high score after VA (p = 0.003). Multivariate cox-regression analysis revealed that CHA₂DS₂-VASC score was also independently associated with all-cause mortality following adjustment for clinically relevant variables (HR 2.20, 1.17–4.14).

Conclusions

CHA₂DS₂-VASC score can be a predictor of CAD leading to PCI in ICD-patients after VA. ICD-Patients with a high score have an increased risk for reduced three-year all-cause mortality after VA.

Echocardiography does not prolong peri-shock pause in cardiopulmonary resuscitation using the COACH-RED protocol with non-expert sonographers in simulated cardiac arrest

OBJECTIVE

Focused echocardiography during peri-shock pause (PSP) can prognosticate and detect reversible causes in cardiac arrest but minimising interruptions to chest compressions improves outcome. The COACH-RED protocol was adapted from the COACHED protocol to systematically incorporate echocardiography into rhythm check without prolonging PSP beyond the recommended 10 s. The primary objective of this study was to test the feasibility of emergency nurses learning to perform all roles in the COACH-RED protocol. PSP duration and change in participant confidence were secondary outcomes.

METHODS

After an initial two-hour workshop, five ALS-trained nurses were assessed for the correct use of COACH-RED protocol, without critical error, in three simulated cardiac arrest scenarios of four cycles each. Assessments were repeated on days 7 and 35. On day 35, three COACHED scenarios were also assessed for comparison. Participant roles per scenario and cardiac rhythm per cycle were randomised. Participants completed questionnaires on their confidence levels. Sessions were videotaped for accurate measurement of PSP duration and results tabulated for simple comparison. Statistical analysis was not performed due to small sample size.

RESULTS

There were no critical errors, two minor team-leading errors and two minor echosonography errors. Minor errors occurred in separate scenarios resulting in a 100% pass rate overall by predetermined criteria. Echocardiographic recordings were 100% adequate. Overall median PSP was 9.35 s for COACH-RED and 6.94 s for COACHED. Sub-group analysis of COACH-RED revealed median PSP 10.80 s in shockable rhythms and 8.74 s (∼2 s less) in non-shockable rhythms. Mean participant confidence in performing COACH-RED improved from 1.6 to 4.6, on a 5-point scale.

CONCLUSION

The COACH-RED protocol can be effectively performed by ALS-trained nurses, in all roles of this protocol, including echocardiography, in a simulated environment, after a single training session. Using this protocol, focused echocardiography does not prolong PSP beyond 10 s.