Intravascular versus surface cooling for targeted temperature management after out-of-hospital cardiac arrest – an analysis of the TTM trial data

Abstract

BackgroundTargeted temperature management is recommended after out-of-hospital cardiac arrest and may be achieved using a variety of cooling devices. This study was conducted to explore the performance and outcomes for intravascular versus surface devices for targeted temperature management after out-of-hospital cardiac arrest.MethodA retrospective analysis of data from the Targeted Temperature Management trial. N = 934. A total of 240 patients (26%) managed with intravascular versus 694 (74%) with surface devices. Devices were assessed for speed and precision during the induction, maintenance and rewarming phases in addition to adverse events. All-cause mortality, as well as a composite of poor neurological function or death, as evaluated by the Cerebral Performance Category and modified Rankin scale were analysed.ResultsFor patients managed at 33 °C there was no difference between intravascular and surface groups in the median time taken to achieve target temperature (210 [interquartile range (IQR) 180] minutes vs. 240 [IQR 180] minutes, p = 0.58), maximum rate of cooling (1.0 [0.7] vs. 1.0 [0.9] °C/hr, p = 0.44), the number of patients who reached target temperature (within 4 hours (65% vs. 60%, p = 0.30); or ever (100% vs. 97%, p = 0.47), or episodes of overcooling (8% vs. 34%, p = 0.15). In the maintenance phase, cumulative temperature deviation (median 3.2 [IQR 5.0] °C hr vs. 9.3 [IQR 8.0] °C hr, p = <0.001), number of patients ever out of range (57.0% vs. 91.5%, p = 0.006) and median time out of range (1 [IQR 4.0] hours vs. 8.0 [IQR 9.0] hours, p = <0.001) were all significantly greater in the surface group although there was no difference in the occurrence of pyrexia. Adverse events were not different between intravascular and surface groups. There was no statistically significant difference in mortality (intravascular 46.3% vs. surface 50.0%; p = 0.32), Cerebral Performance Category scale 3–5 (49.0% vs. 54.3%; p = 0.18) or modified Rankin scale 4–6 (49.0% vs. 53.0%; p = 0.48).ConclusionsIntravascular and surface cooling was equally effective during induction of mild hypothermia. However, surface cooling was associated with less precision during the maintenance phase. There was no difference in adverse events, mortality or poor neurological outcomes between patients treated with intravascular and surface cooling devices.Trial registrationTTM trial ClinicalTrials.gov number https://clinicaltrials.gov/ct2/show/NCT01020916NCT01020916; 25 November 2009

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

“…9 Mean difference in rewarming rates Fig. 10 Mean difference in rewarming times temperature and reducing body temperature fluctuations, thereby reducing the occurrence of adverse events in TH [49]. Although there was no significant difference between the two cooling methods during the rewarming period, the average rewarming speed (0.4°C/h vs. 0.53°C/h) indicates that EC is more in line with the guidelines, which recommend a rewarming speed of 0.25 to 0.5°C/h [10].…”

Review article: Environmental heatstroke and long‐term clinical neurological outcomes: A literature review of case reports and case series 2000–2016

“…There is limited data available surrounding the use of heat exchange catheters in heatstroke and further studies are required, but rapid and specific cooling via this method may offer prompt treatment and therefore improved outcomes. Available studies suggest that intra‐vascular cooling can more precisely maintain a specific target core body temperature …”

Targeted Temperature Management in Traumatic Brain Injury

“…Temperature probe straight connected to the machine provides input data for automatic feedback system [90,91]. The temperature of fluid or air within the pads or blankets is automatically modulated by the system dependent on the setting of target temperature and input data from the temperature probe [92]. The effective ness of this system helps to achieve the ideal process of TTM including rapid lowering the temperature to the target, smooth maintenance of the target temperature, and slow rewarm ing back to the normal setting [46].…”