(1385) A Continuous Objective Shivering Monitor During Targeted Temperature Management After Cardiac Arrest

Introduction: Shivering during targeted temperature management (TTM) is stressful and linked to cerebral metabolic crisis. Few publications report shivering incidence, timing, or severity, and shivering treatment recommendations after cardiac arrest (CA) conflict. To evaluate multimodal shivering assessments, we studied patients during TTM managed with surface cooling, moderate analgosedation, surface counterwarming, and intermittent neuromuscular blockade (NMB).

Methods: Patient data were entered prospectively into the International Cardiac Arrest Registry. Shivering data were prospectively collected for a convenience sample of 104 patients undergoing TTM in a single center. Shivering events (SE) during induction phase (IP - start of TTM to core temperature ≤ 1° C above target temperature) and maintenance phase (end of IP until start of rewarming - divided into early (M1) and late (M2) halves) were compared; SE during rewarming were not included. Continuously recorded surface electromyography (sEMG) patterns (Medtronic BIS monitors) were the primary diagnostic tool for SE, compared to NMB doses administered by bedside nurses for Bedside Shivering Assessment Scale (BSAS) >0. Sedation and analgesia doses were recorded. Outcomes were discharge Cerebral Performance Category (CPC) and survival. Data are presented as median (IQR).

Results: Shivering was more common during TTM induction (0.46 SE/hr) compared to M1 or M2 (both 0.17 SE/hr, p< 0.0001). Shivering was similar for patients targeting 33 vs 36°C (5;3-7 vs 3;2-6 SE, p=0.22). More patients with robust shivering (≥3 SE) survived compared to minimal shivering (51% vs 25%, p=0.027). Among nurse scored SEs, 149 (45%) occurred at temperatures < 33.5°C; BSAS severity was 1 in 207 (65%), 2 in 103 (32%), and 3 in 10 (3%). Total EMG shivering events correlated with BSAS total (0.72,p < 0.001), total NMB doses (0.78,p < 0.0001), but not mean EMG or % time EMG>32. Propofol and fentanyl doses were similar during shivering events for IP versus M.

Conclusions: With similar moderate intensity analgosedation, shivering is most prevalent during TTM induction after CA using surface cooling and counterwarming, with similar intensity at 33 or 36°C targets. More robust shivering was associated with higher survival rates, and nearly half of shivering events occurred below 33.5°C.