Time to Cooling Is Associated with Resuscitation Outcomes

Abstract

Our purpose was to analyze evidence related to timing of cooling from studies of targeted temperature management (TTM) after return of spontaneous circulation (ROSC) after cardiac arrest and to recommend directions for future therapy optimization. We conducted a preliminary review of studies of both animals and patients treated with post-ROSC TTM and hypothesized that a more rapid cooling strategy in the absence of volume-adding cold infusions would provide improved outcomes in comparison with slower cooling. We defined rapid cooling as the achievement of 34°C within 3.5 hours of ROSC without the use of volume-adding cold infusions, with a ≥3.0°C/hour rate of cooling. Using the PubMed database and a previously published systematic review, we identified clinical studies published from 2002 through 2014 related to TTM. Analysis included studies with time from collapse to ROSC of 20–30 minutes, reporting of time from ROSC to target temperature and rate of patients in ventricular tachycardia or ventricular fibrillation, and hypothermia maintained for 20–24 hours. The use of cardiopulmonary bypass as a cooling method was an exclusion criterion for this analysis. We compared all rapid cooling studies with all slower cooling studies of ≥100 patients. Eleven studies were initially identified for analysis, comprising 4091 patients. Two additional studies totaling 609 patients were added based on availability of unpublished data, bringing the total to 13 studies of 4700 patients. Outcomes for patients, dichotomized into faster and slower cooling approaches, were determined using weighted linear regression using IBM SPSS Statistics software. Rapid cooling without volume-adding cold infusions yielded a higher rate of good neurological recovery than slower cooling methods. Attainment of a temperature below 34°C within 3.5 hours of ROSC and using a cooling rate of more than 3°C/hour appear to be beneficial.

Mild therapeutic hypothermia after out-of-hospital cardiac arrest: What does really matter?

“…The authors reported that age, shockable initial rhythm, time in cardiac arrest and induction time > 300 min were associated with a higher probability of a favorable neurologic outcome. In contrast to this, other publications showed rapid TT achievement to be associated with better neurologic results [20][21][22][23]. However, all those studies defined time to TT as the period from the onset of cardiac arrest to arrival at a temperature of 33°C or < 34°C, therefore it was equivalent to three different time intervals used in the current study (time in cardiac arrest, pre-induction and induction).…”

Fast Hypothermia Induced by Continuous Renal Replacement Therapy Alleviates Renal and Intestinal Injury after Cardiac Arrest in Swine

“…Thus, CRRT cooling might be a safe way to induce TH with high e ciency. Additionally, a review [19] demonstrated that the achievement of temperature below 34℃ within 3.5 h after ROSC seemed to be bene cial. In the present study, the blood temperature was initially decreased rapidly by submerging the circuit in ice water to release heat, followed by the maintenance of TH by wrapping the circuit within an adjustable heating device.…”

“…However, despite TH has been proved to exert potent protection for CA survivors [14,15], more than 50% of them die or have poor neurological outcome [16][17][18]. A review demonstrated that rapid cooling exerted a higher rate of good neurological outcome than slower cooling methods [19]. A cooling rate of > 3℃/h appear to be bene cial to arrive at a targeted temperature below 34℃ within 3.5 h after return of spontaneous circulation (ROSC) [19].…”

“…A review demonstrated that rapid cooling exerted a higher rate of good neurological outcome than slower cooling methods [19]. A cooling rate of > 3℃/h appear to be bene cial to arrive at a targeted temperature below 34℃ within 3.5 h after return of spontaneous circulation (ROSC) [19]. Therefore, the undesirable outcome of TH may be deprived from the unsatisfactory cooling effects of traditional methods such as surface blanket cooling, rapid infusion of ice lactated Ringer's solution, etc.…”

State‐of‐the‐art considerations in post‐arrest care

“…Randomized trials have not shown improvement of outcomes with prehospital initiation of therapeutic hypothermia 46,47 . One trial demonstrated worse outcomes in those arriving at goal temperature rapidly while others have demonstrated improved outcomes 48–50 . Unfortunately, none of these trials have stratified enrollment based on initial neurologic injury, limiting the use of their results.…”