Science, Medicine, and the Anesthesiologist

Mild therapeutic hypothermia is recommended by international guidelines in unconscious patients following out-of-hospital cardiac arrest based on two major randomized controlled clinical trials. However, whether the beneficial effects on survival and brain function reported in patients treated with mild hypothermia are linked to effective hypothermia or prevention of fever is unclear. A multicenter, randomized, controlled trial of 950 unconscious survivors of cardiac arrest of presumable cardiac cause found no difference in mortality or in cognitive outcome between patients managed at targeted 33°C versus 36°C temperatures during the 36 h following cardiac arrest. While these results raise questions about the efficacy of hypothermia, they certainly emphasize the importance of controlling temperature and avoiding fever in this context.

Hypothermia is often used to promote brain injury after cardiac arrest. However, the optimal timing in regard to restoration of spontaneous circulation remains unknown. In this randomized controlled trial, 1,359 patients who underwent cardiac arrest with or without ventricular fibrillation were allocated to either immediate cooling upon restoration of spontaneous circulation (infusion of 2 l of 2–4°C saline) followed by 24h in-hospital cooling, or only in-hospital cooling. There was no difference in survival or neurologic outcomes between the prehospital cooling and control groups despite reduced core temperature upon arrival at hospital and faster time to reaching 34°C in the prehospital cooling group.

Sudden unexpected death is the leading cause of death in patients with refractory chronic epilepsy. This retrospective worldwide study examined the cardiorespiratory and electroencephalographic data of these cases when occurring in a monitoring epilepsy unit to better understand underlying mechanisms leading to cardiac arrest in this context. Twenty-nine cases were reported by 147 of the 160 units participating in the survey. A consistent and previously unrecognized centrally mediated breathing pattern following secondarily generalized tonic-clonic seizure and leading to immediate or rapid cardiorespiratory arrest was identified.

Several lines of evidence suggest improved recovery of spontaneous circulation and survival with the vasopressin–steroids–epinephrine combination given during and after cardiopulmonary resuscitation (CPR). This hypothesis was tested in this randomized, blinded, placebo-controlled trial. It was shown that among patients with in-hospital cardiac arrest requiring vasopressors, combined vasopressin (20 IU/CPR cycle) with epinephrine (1 mg/CPR cycle, mean duration of each cycle: 3 min) and methylprednisolone (40 mg) during CPR followed by stress dose hydrocortisone in postresuscitation shock improved survival to hospital discharge with favorable neurological status in comparison with epinephrine–placebo.

Little is known about the long-term outcomes in elderly survivors of in-hospital cardiac arrest. Six thousand nine hundred seventy-two patients older than 65 yr of inpatients with cardiac arrest surviving to discharge from hospital were recruited from a national registry linked to Medicare files. One year after hospital discharge, 58.5% of the patients were alive, 34.4% had not been readmitted to the hospital. The 1-yr survival rate was significantly lower in older versus younger patients. Noteworthy, survival at 3 yr was similar to that of patients with heart failure. Neurological status at discharge was a predictor of survival and readmission to the hospital.

Worldwide, 2.75 billion passengers fly on commercial airlines each year. This study reports in-flight emergencies and the outcomes of these events. One medical emergency per 604 flights was found, the most common cause between syncope or presyncope (32%). Few in-flight emergencies resulted in flight diversion or death, and the death rate of all medical emergencies was 0.3%. An automatic external defibrillator was used in 24 cases of cardiac arrest. A shock was delivered in five cases. All patients but one with restoration of spontaneous circulation survived until discharge to a hospital.

Predicting outcome of patients having survived cardiac arrest remains uncertain. This 3-yr survey identified 51,240 patients with in-hospital cardiac arrest that serve to generate a simple pre-arrest point score allowing identification of patients unlikely to survive in-hospital cardiac arrest, either neurologically intact or with minimal deficits. A simple point score based on 13 pre-arrest variables yielded a good likelihood of outcome. Intact or minimally disabled neurologic status upon admission was a major predictor of good outcome. This result may be helpful as part of a shared decision regarding do-not-attempt resuscitate orders.

This multicenter randomized trial including 2,589 patients with out-of-hospital cardiac arrest showed no difference in 4-h survival between patients treated with a mechanical cardiopulmonary resuscitation (CPR) algorithm in comparison with conventional guideline-adherent manual CPR. The vast majority of survivors had good neurological outcomes at 6 months.