Greater temperature variability is not associated with a worse neurological outcome after cardiac arrest

Effect of different methods of cooling for targeted temperature management on outcome after cardiac arrest: a systematic review and meta-analysis

“…As such, the main difference between the core and invasive methods, in particular EC, was associated with a more strict maintenance of the target temperature during the cooling phase, fewer periods of over-cooling or unexpected rewarming and less temperature variability [14, 19, 25]. Importantly, temperature variability after CA has not been associated with poor neurological outcome in two retrospective studies [41, 42]. Considering also the higher risk of side effects (i.e., infections, thrombosis, hemorrhage) associated with the use of core and invasive TTM systems, in particular EC [12, 24, 43], further studies evaluating the mechanisms involved in potential neuroprotection for such methods are necessary.…”

Intravascular versus surface cooling for targeted temperature management after out-of-hospital cardiac arrest: an analysis of the TTH48 trial

“…We observed a lower TV in the IC-treated patients than in the SFC group. Despite this finding might again underline a higher precision to maintain the target temperature using IC, TV was somewhat higher in patients with favorable than unfavorable neurologic outcome [16] and might suggest intact thermoregulatory pathways that aim to restore a body temperature close to 37.0 °C rather than a target to optimize TTM. The difference in TV was so limited (< 0.1 °C) between groups that one may argue whether this can translate in clinically relevant benefits on patients’ outcome.…”

“…Devices were assessed for (1) time from arrest to target temperature (i.e., < 34.0 °C), (2) time to target temperature (i.e., time from initiation of cooling to first body temperature < 34.0 °C), (3) cooling rate (i.e., changes in temperature from initiation of cooling to first body temperature < 34.0 °C, expressed as °C/h), (4) number of patients achieving the target temperature; (5) overcooling (i.e., at least one body temperature < 32.0 °C), (6) time spent outside targets (i.e., target is within 32 and 34 °C since the first body temperature < 34.0 °C until the initiation of rewarming; time outside target is expressed as number of hours or the percentage of hours according to the duration of cooling), (7) overshoot (i.e., body temperature after rewarming > 36.0 °C during cooling), (8) rewarming rate (i.e., changes in temperature between the initiation of rewarming to the first temperature > 37.0 °C, expressed as °C/h), and (9) post-TTM fever (i.e., number of patients with at least one body temperature measurement after rewarming exceeding 38.0 °C). Precision was assessed by measuring temperature variability (TV), i.e., the standard deviation (SD) of all temperature measurements in the cooling phase [16]. Main adverse events were collected throughout the hospital stay and reported as defined in the main trial [5].…”

Resuscitation highlights in 2015

“…Among 229 comatose survivors treated with TTM after cardiac arrest, 25% of patients had high temperature variability (defined as a standard deviation >1 • C); however, this was not associated with a worse neurologic outcome. 78 Mild hypothermia is generally thought to impair blood clotting; however, in a sub-analysis of 171 patients enrolled into the TTM trial, there was no difference in standard clotting tests or thromboelastography (TEG) values between the 33 • C and the 36 • C groups. 79 Mild hypothermia is know to cause bradycardia but some post-cardiac arrest studies have shown an association between bradycardia and a good outcome.…”