[Endovascular or surface cooling?: therapeutic hypothermia after cardiac arrest]

Intravascular Versus Surface Cooling in Patients Resuscitated From Cardiac Arrest: A Systematic Review and Network Meta-Analysis With Focus on Temperature Feedback

OBJECTIVE

The aim of the study was to compare the effect of intravascular cooling (IC), surface cooling with temperature feedback (SCF), and surface cooling without temperature feedback (SCnoF) on neurologic outcome and survival in patients successfully resuscitated from cardiac arrest (CA) and treated with targeted temperature management (TTM) at 32-34°C.

DATA SOURCES

We performed a systematic review on Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, MEDLINE, SCOPUS, CINAHL, Web of Science, and Clinical Trials up to June 30, 2021.

STUDY SELECTION

We included randomized and nonrandomized studies on IC, SCF, and SCnoF in adult humans resuscitated from CA undergoing TTM, reporting neurologic outcome or survival.

DATA EXTRACTION

We performed a network meta-analysis to assess the comparative effects of IC, SCF, and SCnoF. The overall effect between two cooling methods included the effect of direct and indirect comparisons. Results are given as odds ratios (OR) and 95% CIs. Rankograms estimated the probability of TTM methods being ranked first, second, and third best interventions.

DATA SYNTHESIS

A total of 14 studies involving 4,062 patients met the inclusion criteria. Four studies were randomized controlled studies, and 10 studies were nonrandomized observational studies. IC compared with SCnoF was significantly associated with better neurologic outcome (OR, 0.6; 95% CI, 0.49-0.74) and survival (OR, 0.8; 95% CI, 0.66-0.96). IC compared with SCF, and SCF compared with SCnoF did not show significant differences in neurologic outcome and survival. The rankogram showed that IC had the highest probability to be the most beneficial cooling method, followed by SCF and SCnoF.

CONCLUSIONS

Our results suggest that in patients resuscitated from CA and treated with TTM at 32-34°C, IC has the highest probability of being the most beneficial cooling method for survival and neurologic outcome.

Efficacy of the cooling method for targeted temperature management in post-cardiac arrest patients: A systematic review and meta-analysis

OBJECTIVE

This review aimed to compare the efficacy of endovascular cooling devices (ECD), such as Thermogard®, with surface cooling devices (SCD), such as Arctic Sun®, in reducing mortality and improving neurological status for patients with post-cardiac arrest undergoing targeted temperature management.

DATA SOURCES

A systematic literature search was conducted using MEDLINE, EMBASE, and the Cochrane Library to identify randomized controlled trials (RCT) and observational studies (OS) comparing mortality and neurological status for patients treated with ECD or SCD.

RESULTS

The meta-analysis comprised 4,401 patients from 2 RCT and 7 OS. For mortality, the overall pooled analysis showed no statistically significant difference between ECD and SCD recipients (RR, 0.93; 95% CI 0.86-1.00; I2 = 0%). Further, no statistically significant difference was observed between RCT (RR, 0.80; 95% CI 0.56-1.14; I2 = 0%) and OS (RR, 0.94; 95% CI 0.85-1.04; I2 = 18%) for in-hospital mortality. For good neurological status of survivors after TTM, the overall pooled analysis showed no statistically significant difference between ECD and SCD (RR, 1.08; 95% CI 0.99-1.18; I2 = 71%). No statistically significant difference was found between ECD and SCD at hospital discharge in RCT (RR, 0.88; 95% CI 0.61-1.28; I2 = 0%) and at 6 months in OS (RR, 1.03; 95% CI 0.99-1.09; I2 = 32%).

CONCLUSIONS

The study findings could not show that either ECD or SCD was more effective in terms of survival and improved neurological status for post-cardiac arrest patients.

SYSTEMATIC REVIEW REGISTRATION NUMBER

CRD42019129770.

Effects of endovascular and surface cooling on resuscitation in patients with cardiac arrest and a comparison of effectiveness, stability, and safety: a systematic review and meta-analysis

Objectives

This study conducted a meta-analysis to assess the effectiveness, stability, and safety of mild therapeutic hypothermia (TH) induced by endovascular cooling (EC) and surface cooling (SC) and its effect on ICU, survival rate, and neurological function integrity in adult CA patients.

Methods

We developed inclusion criteria, intervention protocols, results, and data collection. The results included outcomes during target temperature management as well as ICU stay, survival rate, and neurological functional integrity. The characteristics of the included population and each study were analyzed.

Results

Four thousand nine hundred thirteen participants met the inclusion criteria. Those receiving EC had a better cooling efficiency (cooling rates MD = 0.31[0.13, 0.50], p < 0.01; induced cooling times MD = − 90.45[− 167.57, − 13.33], p = 0.02; patients achieving the target temperature RR = 1.60[1.19, 2.15], p < 0.01) and thermal stability during the maintenance phase (maintenance time MD = 2.35[1.22, 3.48], p < 0.01; temperature fluctuation MD = − 0.68[− 1.03, − 0.33], p < 0.01; overcooling RR = 0.33[0.23, 0.49], p < 0.01). There were no differences in ICU survival rate (RR = 1.22[0.98, 1.52], p = 0.07, I² = 0%) and hospital survival rate (RR = 1.02 [0.96, 1.09], p = 0.46, I² = 0%), but EC reduced the length of stay in ICU (MD = − 1.83[− 3.45, − 0.21], p = 0.03, I² = 49%) and improved outcome of favorable neurological function at discharge (RR = 1.15[1.04, 1.28], p < 0.01, I² = 0%). EC may delay the hypothermia initiation time, and there was no significant difference between the two cooling methods in the time from the start of patients’ cardiac arrest to achieve the target temperature (MD = − 46.64[− 175.86, 82.58]). EC was superior to non-ArcticSun in terms of cooling efficiency. Although there was no statistical difference in ICU survival rate, ICU length of stay, and hospitalization survival rate, in comparison to non-ArcticSun, EC improved rates of neurologically intact survival (RR = 1.16 [1.01, 1.35], p = 0.04, I² = 0%).

Conclusions

Among adult patients receiving cardiopulmonary resuscitation, although there is no significant difference between the two cooling methods in the time from the start of cardiac arrest to achieve the target temperature, the faster cooling rate and more stable cooling process in EC shorten patients’ ICU hospitalization time and help more patients obtain good neurological prognosis compared with patients receiving SC. Meanwhile, although EC has no significant difference in patient outcomes compared with ArcticSun, EC has improved rates of neurologically intact survival.

Mild hypothermia for refractory focal status epilepticus in an infant with hemimegalencephaly

Hypothermia can reduce seizure frequency in animal models of status epilepticus, and its effectiveness in human status epilepticus has been reported occasionally. We report an infant with hemimegalencephaly who presented with generalized status epilepticus. After high dose intravenous drug therapy, this converted to focal status epilepticus in the right occipital region. A sudden cessation of all seizure activity was found to coincide with accidental hypothermia. After application of mild continuous hypothermia, a marked reduction of seizure frequency occurred, which allowed reduction of intravenous drug doses and discharge from the IC unit. Ultimately, hemispherectomy was needed to achieve long term seizure control. The therapeutic effect of hypothermia should be further investigated in patients with refractory status epilepticus. When used in combination with anti-epileptic drugs, seizure control may be achieved at lower doses. Hypothermia may obviate the need for potentially dangerous barbiturate therapy. This case demonstrates that even a mild degree of hypothermia (+/-36 degrees C) can be remarkably effective.