Cardiac Arrest


COCHRANE SYSTEMATIC REVIEW: Amiodarone versus other pharmacological interventions for prevention of sudden cardiac death
Implications for practice: There is low to moderate quality evidence that amiodarone reduces cardiac and all-cause mortality
Review Overview: We included 24 studies (9,997 participants). Seventeen studies evaluated amiodarone for primary prevention and six for secondary prevention. Only three studies used an ICD concomitantly with amiodarone for the comparison (all of them for secondary prevention). For primary prevention, amiodarone compared to placebo or no intervention (17 studies, 8383 participants) reduced SCD (RR 0.76; 95% CI 0.66 to 0.88), cardiac mortality (RR 0.86; 95% CI 0.77 to 0.96) and all-cause mortality (RR 0.88; 95% CI 0.78 to 1.00). The quality of the evidence was low. Compared to other antiarrhythmics (three studies, 540 participants), amiodarone reduced SCD (RR 0.44; 95% CI 0.19 to 1.00), cardiac mortality (RR 0.41; 95% CI 0.20 to 0.86) and all-cause mortality (RR 0.37; 95% CI 0.18 to 0.76). The quality of the evidence was moderate. For secondary prevention, amiodarone compared to placebo or no intervention (two studies, 440 participants) appeared to increase the risk of SCD (RR 4.32; 95% CI 0.87 to 21.49) and all-cause mortality (RR 3.05; 1.33 to 7.01). However, the quality of the evidence was very low. Compared to other antiarrhythmics (four studies, 839 participants) amiodarone appeared to increase the risk of SCD (RR 1.40; 95% CI 0.56 to 3.52; very low quality of evidence), but there was no effect in all-cause mortality (RR 1.03; 95% CI 0.75 to 1.42; low quality evidence). Amiodarone was associated with an increase in pulmonary and thyroid adverse events. Authors' conclusions There is low to moderate quality evidence that amiodarone reduces SCD, cardiac and all-cause mortality when compared to placebo or no intervention for primary prevention, and its effects are superior to other antiarrhythmics. It is uncertain if amiodarone reduces or increases SCD and mortality for secondary prevention because the quality of the evidence was very low.
LINK to Cochrane Library: Issue 12, 2015 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD008093.pub2/abstract


COCHRANE SYSTEMATIC REVIEW: Hypothermia for neuroprotection in children after cardiopulmonary arrest
Implications for practice: Research is ongoing on this topic.
Review Overview: Cardiopulmonary arrest in children is uncommon however the numbers of children who survive are very low. Resulting brain injury in the survivors can be devastating for the child and family. Cooling the patient to a temperature of 32 °C to 34 °C, which is 3 °C to 4 °C below normal (therapeutic hypothermia), has previously been found to improve survival and reduce brain injury in newborn infants who were deprived of oxygen during birth, and also in adults following cardiopulmonary arrest. The causes of cardiopulmonary arrest are different in children than in adults, and asphyxia at birth is also different, so the effect of therapeutic hypothermia on the proportion of children who survive or who have brain injury is unclear. We therefore conducted a Cochrane systematic review of the literature, searching medical databases (CENTRAL, MEDLINE, EMBASE) until December 2011 and contacting international experts for high quality published and unpublished evidence. Our searches failed to find any randomized controlled studies that met our inclusion criteria. However, we found four on-going trials which, when completed, may contribute to our review. At present there is no evidence from randomized controlled trials to support or refute the use of therapeutic hypothermia within a few hours after return of spontaneous blood flow following cardiopulmonary arrest in children. International resuscitation guidelines currently recommend that doctors consider using the therapy in infants and children although more research is needed to be sure this is the correct recommendation with the lack of treatment options other than supportive care in an intensive care unit that are available.
LINK to Cochrane Library: Issue 2, 2013 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009442.pub2/abstract


COCHRANE SYSTEMATIC REVIEW: Active chest compression‐decompression for cardiopulmonary resuscitation
Implications for practice: Active chest compression-decompression in people with cardiac arrest is not associated with any clear benefit.
Review Overview: Out-of-hospital trials cumulated 4162 participants. There were no differences between ACDR CPR and STR for mortality either immediately (RR 0.98, 95% confidence interval (CI) 0.94 to 1.03) or at hospital discharge (RR 0.99, 95% CI 0.98 to 1.01). The pooled RR of neurological impairment of any severity was 1.71 (95% CI 0.90 to 3.25), with a non-significant trend to more frequent severe neurological damage in survivors of ACDR CPR (RR 3.11, 95% CI 0.98 to 9.83). However, assessment of neurological outcome was limited, and few participants had neurological damage.
LINK to Cochrane Library: Issue 9, 2013 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD002751.pub3/abstract


COCHRANE SYSTEMATIC REVIEW: Aminophylline for bradyasystolic cardiac arrest in adults
Implications for practice: The prehospital administration of aminophylline in bradyasystolic arrest is not associated with improved return of circulation, survival to admission or survival to hospital discharge.
Review Overview: Drugs are used to resuscitate patients from cardiac arrest. Aminophylline is a drug that might help patients in cardiac arrest when electrical activity is very slow or absent. Aminophylline may restore blood flow to the heart, improve electrical activity and make other drugs used in resuscitation more effective. We found five studies that included 1254 patients who had this type of cardiac arrest in the prehospital setting. Four of the five studies (1186 patients) were well-designed studies with low risk of bias. Although no adverse events were reported, aminophylline added to the standard resuscitation practice of paramedics showed no advantage when compared with placebo in these patients. It is not known whether giving aminophylline sooner would be helpful.
LINK to Cochrane Library: Issue 8, 2013 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006781.pub2/abstract


COCHRANE SYSTEMATIC REVIEW: Mechanical versus manual chest compressions for cardiac arrest
Implications for practice: Evidence from RCTs in humans is insufficient to conclude that mechanical chest compressions during cardiopulmonary resuscitation for cardiac arrest are associated with benefit or harm. Widespread use of mechanical devices for chest compressions during cardiac events is not supported by this review.
Review Overview: We found that only six articles described clinical trials that could help us answer our question. Taken together, these trials included 1166 participants. The largest study found that patients who received treatment with a mechanical device had a lower chance of survival than patients treated with chest compressions applied by hand. Some problems were associated with the methods used in this trial, which may explain these unexpected results. Two smaller studies found that more patients treated with machine chest compressions had their hearts restart, but these studies were so small that the validity of this finding is unclear. Of the two new studies identified in this update, one demonstrated that patients in the group that received mechanical chest compressions more often had their heart restart and survived to the point of leaving the hospital when compared with patients who received chest compressions by hand. The other new study showed no difference between groups when researchers compared the likelihood of patients having their heart restart or being alive at the time of hospital admission or discharge. The most important finding of our study was that not enough data are available from good-quality trials to answer our question and support a recommendation on whether these machines should be used. The current body of research comparing machine chest compressions versus hand chest compressions is not sufficient to indicate which technique is best. Very few studies have been conducted, and the studies reported had some major design problems. These studies provided results that are conflicting with respect to whether mechanical chest compressions improve survival. Several large randomised trials designed to answer this question are currently under way, and these results are expected in the next one to two years.
LINK to Cochrane Library: Issue 2 2014 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD007260.pub3/abstract


COCHRANE SYSTEMATIC REVIEW: Aminophylline for bradyasystolic cardiac arrest in adults
Implications for practice: Aminophylline has no currently known benefit for bradyasystolic cardiac arrest
Review Overview: We included five trials in this analysis, all of which were performed in the prehospital setting. The risk of bias was low in four of these studies (n = 1186). The trials accumulated 1254 participants. Aminophylline was found to have no effect on survival to hospital discharge (risk ratio (RR) 0.58, 95% confidence interval (CI) 0.12 to 2.74) or on secondary survival outcome (survival to hospital admission: RR 0.92, 95% CI 0.61 to 1.39; return of spontaneous circulation: RR 1.15, 95% CI 0.89 to 1.49). Survival was rare (6/1254), making data about neurological outcomes and adverse events quite limited. The planned subgroup analysis for early administration of aminophylline included 37 participants. No one in the subgroup survived to hospital discharge. Authors' conclusions The prehospital administration of aminophylline in bradyasystolic arrest is not associated with improved return of circulation, survival to admission or survival to hospital discharge. The benefits of aminophylline administered early in resuscitative efforts are not known.
LINK to Cochrane Library: Issue 11, 2015 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006781.pub3/abstract