Mild hypothermia induced by a helmet device: a clinical feasibility study. High-volume hemofiltration after out-of-hospital cardiac arrest: a randomized study. Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia.
To test the feasibility and the speed of a helmet device to achieve the target temperature of 34 degrees C in unconscious after out of hospital cardiac arrest (CA).
                Patients with cardiac arrest due to asystole or pulseless electrical activity (PEA) who remained unconscious after restoration of spontaneous circulation (ROSC) were enrolled in the study and randomised into two groups: a normothermic group (NG) and a hypothermic group (HG). Bladder and tympanic temperature were monitored every 15 min. A helmet device was used to induce mild hypothermia in the HG. Later on, the effect of mild hypothermia on the haemodynamics, electrolytes, lactate, arterial pH, CaO2, CvO2 and O2 extraction ratio were analysed and compared to the values obtained from the NG.
                Thirty patients were eligible for the study, 16 were randomised into the HG and 14 were randomised into the NG. The median tympanic temperature at admission in both groups was 35.5 degrees C (range: 33.3-38.5 degrees C) and the median tympanic temperature after haemodynamic stabilisation was 35.7 degrees C (range: 33.6-38.2 degrees C). In the HG, the core and the central target temperature of 34 degrees C were achieved after a median time of 180 and 60 min, respectively after ROSC. At the start of the study, no significant differences between the NG and HG were seen. At the end of the study, lactate concentration and O2 extraction ratio were significantly lower in the HG; however the CvO2 was significantly lower in the NG.
                Mild hypothermia induced by a helmet device was feasible, easy to perform, inexpensive and effective, with no increase in complications. The study examined the effect of isovolumic high-volume hemofiltration (HF) alone or combined with mild hypothermia (HT) on survival after out-of-hospital cardiac arrest (OHCA) with initial ventricular fibrillation or asystole.
                Global inflammation in response to whole-body ischemia-reperfusion is common after OHCA and may worsen the overall prognosis.
                Sixty-one patients admitted between May 2000 and March 2002 in the intensive care units of two hospitals in France were randomized to one of three groups: control, HF (200 ml/kg/h over 8 h) or HF+HT (32 degrees C for 24 h) induced by cooling the HF substitution fluid. Standard supportive care was provided in all three groups. The primary end point was survival with a follow-up time of six months. The effect of HF on death by intractable shock was the secondary end point.
                The six-month survival curves of the three groups were significantly different, with better survival in the HF group (p = 0.026) and in the HF+HT group (p = 0.018). After adjustment on baseline characteristics of cardiac arrest, HF (with or without HT) was associated with improved survival (logistic regression odds ratio, 4.4; 95% confidence interval [CI], 1.1 to 16.6). Compared to control group, the relative risk of death by intractable shock was 0.29 (95% CI, 0.09 to 0.91) in the HF+HT group and 0.21 (95% CI, 0.05 to 0.85) in the HF group.
                The HF may improve the overall prognosis after resuscitation from OHCA. Combination of HF with mild HT is feasible and should be evaluated in larger trials. Cardiac arrest outside the hospital is common and has a poor outcome. Studies in laboratory animals suggest that hypothermia induced shortly after the restoration of spontaneous circulation may improve neurologic outcome, but there have been no conclusive studies in humans. In a randomized, controlled trial, we compared the effects of moderate hypothermia and normothermia in patients who remained unconscious after resuscitation from out-of-hospital cardiac arrest.
                The study subjects were 77 patients who were randomly assigned to treatment with hypothermia (with the core body temperature reduced to 33 degrees C within 2 hours after the return of spontaneous circulation and maintained at that temperature for 12 hours) or normothermia. The primary outcome measure was survival to hospital discharge with sufficiently good neurologic function to be discharged to home or to a rehabilitation facility.
                The demographic characteristics of the patients were similar in the hypothermia and normothermia groups. Twenty-one of the 43 patients treated with hypothermia (49 percent) survived and had a good outcome--that is, they were discharged home or to a rehabilitation facility--as compared with 9 of the 34 treated with normothermia (26 percent, P=0.046). After adjustment for base-line differences in age and time from collapse to the return of spontaneous circulation, the odds ratio for a good outcome with hypothermia as compared with normothermia was 5.25 (95 percent confidence interval, 1.47 to 18.76; P=0.011). Hypothermia was associated with a lower cardiac index, higher systemic vascular resistance, and hyperglycemia. There was no difference in the frequency of adverse events.
                Our preliminary observations suggest that treatment with moderate hypothermia appears to improve outcomes in patients with coma after resuscitation from out-of-hospital cardiac arrest.