Regional cerebral oxygen saturation in cardiac arrest survivors undergoing targeted temperature management 36 °C versus 33 °C: A randomized clinical trial

Abstract

Aim of study: To investigate whether regional cerebral oxygen saturation (rSO 2 ) diers in out-of-hospital cardiac arrest (OHCA) survivors undergoing targeted temperature management (TTM) 36°C versus 33°C. Methods: A randomized clinical trial was conducted at intensive care units in two referral hospitals. Fifty-seven comatose OHCA survivors were randomized into either a 36°C or 33°C group. Patients were cooled and maintained at an oesophageal temperature of either 36°C or 33°C for 24 hours, rewarmed at a rate of 0.25°C/hour, and maintained at <37.5°C until 72 hours. During 72 hours of TTM, rSO 2 was continuously monitored on the left forehead using near-infrared spectroscopy (INVOS TM 5100C). The rSO 2 level at 72 hours was compared between the two groups. Next, serial rSO 2 levels for 72 hours were compared using mixed eects regression. The association between rSO 2 levels and 6-month neurological outcomes was also evaluated. Results: There were no significant dierences in the rSO 2 level at 72 hours between the 36°C and 33°C groups (p = 0.372). Furthermore, serial rSO 2 levels for 72 hours of TTM were not dierent between the two groups (p = 0.733). However, low rSO 2 levels, particularly at 24 hours of TTM, were significantly associated with poor 6-month neurological outcomes (odds ratio = 0.899, 95% confidence interval: 0.831-0.974). The area under the receiver operating characteristic curve of the rSO 2 level at 24 hours for poor neurological outcomes was 0.800. Conclusions: Regardless of target temperatures, low rSO 2 levels during TTM were significantly associated with poor 6-month neurological outcomes in OHCA survivors.

Conflicting guidelines: a commentary on the recent European Society for Emergency Medicine and European Society of Anaesthesiology and Intensive Care guidelines on temperature control after cardiac arrest

“…This is especially true for a complex intervention such as temperature control. Assuming no unmeasured or residual 24 32 to 34 8C 105 min a NR 8 h Laurent, 2005 25 32 8C N R N R N R Hachimi-Idrissi, 2005 13 33 8C N R N R N R Nielsen, 2013 10 33 8C N R 3 ht o<34 8C b NR Lascarrou, 2019 26 33 8C 233 min 317 min to 33 8C 9 h Dankiewicz, 2021 27 33 8C 111 min 3 h to 34 8C 5 h Kwon, 2021 28 33 8C N R N R 5t o6 h b Wolfrum, 2022 18 33 8C 2 h a 4.2 h to <34 8C confounding is a very strong assumption that we consider unlikely to be true in this context. Again, observational studies should be used only to support clinical guidelines if no, or few interventional trials are available.…”