George Karlis

Enhanced external counterpulsation: mechanisms of action and clinical applications

Symptomatic coronary artery disease (CAD) and heart failure (HF), either of ischaemic or nonischaemic aetiology, are common medical problems. Despite optimal medical treatment and improved revascularisation techniques, a significant number of patients are not successfully managed. Among the non-pharmacological, alternative, non-invasive treatments suggested for these patients, enhanced external counterpulsation (EECP) is considered the most effective one. EECP, administered in an outpatient setting, consists of three pneumatic cuffs applied to each of the patient’s legs that are sequentially inflated and deflated synchronised with the cardiac cycle. Numerous clinical trials have shown that EECP is safe and effective in patients with ischaemic heart disease, with or without left ventricular dysfunction, improving their quality of life. EECP appears to be beneficial as an adjunctive therapy in patients with HF of any aetiology. Cardiac syndrome X has been shown to be effectively treated with EECP. Research in EECP expanded in its potential use for entities other than heart disease. More trials are necessary, including sham-controlled trials, to further establish EECP among medical society.

Amiodarone and cardiac arrest: Systematic review and meta-analysis

INTRODUCTION The 2015 Guidelines for Resuscitation recommend amiodarone as the antiarrhythmic drug of choice in the treatment of resistant ventricular fibrillation or pulseless ventricular tachycardia. We reviewed the effects of amiodarone on survival and neurological outcome after cardiac arrest. METHODS We systematically searched MEDLINE and Cochrane Library from 1940 to March 2016 without language restrictions. Randomized control trials (RCTs) and observational studies were selected. RESULTS Our search initially identified 1663 studies, 1458 from MEDLINE and 205 from Cochrane Library. Of them, 4 randomized controlled studies and 6 observational studies met the inclusion criteria and were selected for further review. Three randomized studies were included in the meta-analysis. Amiodarone significantly improves survival to hospital admission (OR=1.402, 95% CI: 1.068-1.840, Z=2.43, P=0.015), but neither survival to hospital discharge (RR=0.850, 95% CI: 0.631-1.144, Z=1.07, P=0.284) nor neurological outcome compared to placebo or nifekalant (OR=1.114, 95% CI: 0.923-1.345, Z=1.12, P=0.475). CONCLUSIONS Amiodarone significantly improves survival to hospital admission. However there is no benefit of amiodarone in survival to discharge or neurological outcomes compared to placebo or other antiarrhythmics.

Theoretical knowledge and skill retention 4 months after a European Paediatric Life Support course.

Objective The European Paediatric Life Support (EPLS) provider course aims at training doctors and nurses in the efficient and prompt management of cardiopulmonary arrest in children. EPLS is a 2-day European Resuscitation Council course, involving the teaching of theoretical knowledge and practical skills. The aim of the study was to evaluate the retention of theoretical knowledge and certain skills of EPLS providers 4 months after the course. Materials and methods In total, 80 doctors and nurses who attended three EPLS provider courses, from May 2012 to December 2012, were asked to participate in the study and only 50 responded positively. Demographic data (age, sex, occupation) of the participants were collected. The European Resuscitation Council-approved EPLS written test was used to assess theoretical knowledge right after the course and after 4 months. The retention of certain skills (airway opening, bag-mask ventilation, chest compressions) was also examined. Results The theoretical knowledge decreased significantly (P<0.001) 4 months after the course. Age, sex and occupational status (medical or nursing profession) had no effect in theoretical knowledge retention. Interestingly, certain skills such as the application of airway opening manoeuvres and effective bag-mask ventilation were retained 4 months after the course, whereas chest compression skill retention significantly declined (P=0.012). Conclusion According to our findings, theoretical knowledge of the EPLS course uniformly declines, irrespective of the provider characteristics, whereas retention of certain skills is evident 4 months after the course.

Body mass index and outcome of out-of-hospital cardiac arrest patients not treated by targeted temperature management ☆ ☆☆

Background: Obesity has been demonstrated to increase the risk of out‐of‐hospital cardiac arrest (OHCA) and may influence the quality and effectiveness of cardiopulmonary resuscitation. Our aim was to investigate the association between body mass index (BMI) and the outcome of OHCA victims not treated by targeted temperature management. Methods: This was a prospective observational study of OHCA patients. The patients were categorized according to BMI into two groups: the normal BMI group (nBMI) and the elevated BMI group (eBMI). The primary endpoint was return of spontaneous circulation (ROSC), while secondary outcomes were survival to intensive care unit (ICU) admission and survival to ICU discharge. Results: Of the initial 99 patients who were transported to the Emergency Department, 84 (85%) were included in the study. Mean BMI was 29.8 kg/m2. Thirteen (15.5%) patients achieved ROSC and were admitted to the ICU, with the mean duration of ICU length of stay being 6.7 ± 4.9 days. Survival to ICU admission and ICU discharge were higher in the eBMI group (17.6% vs. 6.25%, p = 0.010 and 10.3% vs. 6.25%, p = 0.021, respectively). Survival to ICU discharge was higher in ventricular fibrillation patients compared to patients with non‐shockable rhythms, irrespectively of their BMI (p = 0.002). All patients that survived to ICU discharge did so with a cerebral performance category score of 2. Conclusions: Survival to ICU admission and ICU discharge were higher in the eBMI group.

Exposure to Stress-Dose Steroids and Lethal Septic Shock After In-Hospital Cardiac Arrest: Individual Patient Data Reanalysis of Two Prior Randomized Clinical Trials that Evaluated the Vasopressin–Steroids–Epinephrine Combination Versus Epinephrine Alone

PurposeLow-dose steroids may reduce the mortality of severely ill patients with septic shock. We sought to determine whether exposure to stress-dose steroids during and/or after cardiopulmonary resuscitation is associated with reduced risk of death due to postresuscitation septic shock.MethodsWe analyzed pooled, individual patient data from two prior, randomized clinical trials (RCTs). RCTs evaluated vasopressin, steroids, and epinephrine (VSE) during resuscitation and stress-dose steroids after resuscitation in vasopressor-requiring, in-hospital cardiac arrest. In the second RCT, 15 control group patients received open-label, stress-dose steroids. Patients with postresuscitation shock were assigned to a Steroids (n = 118) or No Steroids (n = 73) group according to an “as-treated” principle. We used cumulative incidence competing risks Cox regression to determine cause-specific hazard ratios (CSHRs) for pre-specified predictors of lethal septic shock (primary outcome). In sensitivity analyses, data were analyzed according to the intention-to-treat (ITT) principle (VSE group, n = 103; control group, n = 88).ResultsLethal septic shock was less likely in Steroids versus No Steroids group, CSHR, 0.40, 95% confidence interval (CI), 0.20–0.82; p = 0.012. ITT analysis yielded similar results: VSE versus Control, CSHR, 0.44, 95% CI, 0.23–0.87; p = 0.019. Adjustment for significant, between-group baseline differences in composite cardiac arrest causes such as “hypotension and/or myocardial ischemia” did not appreciably affect the aforementioned CSHRs.ConclusionsIn this reanalysis, exposure to stress-dose steroids (primarily in the context of a combined VSE intervention) was associated with lower risk of postresuscitation lethal septic shock.

Drugs in cardiac arrest: the rise and fall of antiarrhythmics

Abstract Since the publication of 2000 guidelines for resuscitation, amiodarone is considered the antiarrhythmic drug of choice for refractory ventricular fibrillation/pulseless ventricular tachycardia. However, to date there is no proven benefit in terms of neurologically intact survival to hospital discharge. A comprehensive search of the recent literature on amiodarone, nifekalant and lidocaine in cardiac arrest was performed. Amiodarone and nifekalant are superior to lidocaine with regards to the return of spontaneous circulation and survival to hospital admission. Nifekalant shows a trend towards quicker termination of ventricular fibrillation compared to amiodarone. There is great uncertainty about the efficacy of antiarrhythmics in cardiac arrest. Failure to show improvements regarding meaningful survival questions their current use and suggests the need for re-evaluating their place in cardiopulmonary resuscitation.

Ventilation Strategies: High-Frequency Oscillatory Ventilation

High-frequency oscillatory ventilation (HFOV) comprises superimposition of pressure oscillations on a continuous positive airway pressure, termed mean airway pressure. Administered tidal volumes (usual range, 40–210 mL) depend on oscillation frequency (usual range, 3.5–10 Hz) and oscillatory pressure amplitude. Theoretically, HFOV is ideal for lung protection in the acute respiratory distress syndrome (ARDS), as it may minimize the risk of volutrauma and atelectrauma. Prior laboratory studies and the pooled results of prior, small randomized controlled trials (RCTs) of HFOV vs. conventional ventilation (CV) in ARDS were suggestive of an HFOV-associated mortality benefit. However, this hypothesis was refuted by the results of two recent large RCTs of HFOV vs. lung-protective CV. The one RCT reported no difference in mortality between treatment arms, whereas the other RCT reported an HFOV-associated harm. The latter result could be partly due to HFOV-induced dysfunction of the right ventricle (RV). In the present chapter, we provide a brief summary of the mechanisms of gas exchange during HFOV and then review published physiological and RCT data, in order to provide a rationale for selecting HFOV settings so as to achieve both lung and RV protection. In this context, we also review available data on the combination of HFOV with tracheal gas insufflation (TGI) and attempt to establish a background for future clinical research involving lung and RV protective HFOV with or without TGI. Future research could also evaluate combination treatments such as prone, lung-protective CV interspersed with supine HFOV.

Correlation of Impedance Threshold Device use during cardiopulmonary resuscitation with post-cardiac arrest Acute Kidney Injury

Purpose To assess whether use of Impedance Threshold Device (ITD) during cardiopulmonary resuscitation (CPR) reduces the degree of post‐cardiac arrest Acute Kidney Injury (AKI), as a result of improved hemodynamics, in a porcine model of ventricular fibrillation (VF) cardiac arrest. Methods After 8 min of untreated cardiac arrest, the animals were resuscitated either with active compression‐decompression (ACD) CPR plus a sham ITD (control group, n = 8) or with ACD‐CPR plus an active ITD (ITD group, n = 8). Adrenaline was administered every 4 min and electrical defibrillation was attempted every 2 min until return of spontaneous circulation (ROSC) or asystole. After ROSC the animals were monitored for 6 h under general anesthesia and then returned to their cages for a 48 h observation, before euthanasia. Two novel biomarkers, Neutrophil Gelatinase‐Associated Lipocalin (NGAL) in plasma and Interleukin‐18 (IL‐18) in urine, were measured at 2 h, 4 h, 6 h, 24 h and 48 h post‐ROSC, in order to assess the degree of AKI. Results ROSC was observed in 7 (87.5%) animals treated with the sham valve and 8 (100%) animals treated with the active valve (P = NS). However, more than twice as many animals survived at 48 h in the ITD group (n = 8, 100%) compared to the control group (n = 3, 37.5%). Urine IL‐18 and plasma NGAL levels were augmented post‐ROSC in both groups, but they were significantly higher in the control group compared with the ITD group, at all measured time points. Conclusion Use of ITD during ACD‐CPR improved hemodynamic parameters, increased 48 h survival and decreased the degree of post‐cardiac arrest AKI in the resuscitated animals.