(1099) Retrospective Evaluation of Sedation and Shivering Management in Targeted Temperature Management (TTM) for Post-cardiac Arrest Care at a Community Teaching Hospital

Objectives: Evidence suggests using a stepwise manner to manage shivering in patients receiving targeted temperature management (TTM) post-cardiac arrest with non-pharmacological measures for Bedside Shivering Assessment Scale (BSAS) of 1. Opioids and sedatives are recommended for BSAS of 1 or 2, while neuromuscular blockers are reserved for refractory shivering or BSAS of 3. Acetaminophen and magnesium are typically suggested as a shivering prophylaxis measure. The most optimal shivering management and prevention method is not defined. This project evaluated the sedation and opioid regimens used in TTM and assessed the compliance with the stepwise hospital shivering management protocol.

Methods: This was a single-center, retrospective chart review of patients admitted to the intensive care unit (ICU) from September 2018 to June 2023 who received TTM post-cardiac arrest. Exclusion criteria were patients who expired within 24 hours or had incomplete data. Patients were categorized as TTM-33 or TTM-36 based on the targeted temperatures of 33 or 36°C respectively. Data collection included patient demographics, type and cause of cardiac arrest, ICU length of stay, status at discharge, admission Glasgow Coma Scale, time at return of spontaneous circulation (ROSC), first body temperature post-ROSC, and TTM start time. In addition, within 96 hours of TTM initiation, the incidence and management of shivering (based on BSAS), seizure, bleeding, arrhythmias, hypo/hyperglycemia, hypo/hyperkalemia, and acute kidney injury were collected. The incidence of new infections requiring antibiotics within 7 days of TTM initiation was recorded. The primary outcome is the median amount of each sedating medication used to control shivering within the first 96 hours post-TTM initiation. Using ClinCalc, midazolam equivalent was used to calculate benzodiazepine total amount, while morphine equivalent was used for opioid aggregate amount. The secondary outcome is the compliance rate of shivering management according to the hospital protocol. This study was approved by the institutional review boards.

Results: Fifty-eight patients were included with 42 out-of-hospital cardiac arrests; 40 patients received TTM-33, while 18 received TTM-36. The median weight was 72kg and 81kg for TTM-33 and TTM-36 respectively. Within the first 96 hours post-TTM initiation, 44 patients (76%) received propofol monotherapy, while 12 received either benzodiazepine monotherapy or propofol and benzodiazepine combination. For TTM-33 and TTM-36, the median (IQR) propofol amount was 1645mg (617–3060) and 3033mg (1501–4087) respectively; the median benzodiazepine equivalent amount was 22mg (5–54) and 1.3mg (0.9–1.7) respectively. Twenty-eight patients received opioids as continuous infusions (CI) with as needed (PRN) boluses, 15 as PRN boluses only, and five as CI monotherapy. The median morphine equivalent amount was 41.25mg (1.22–91.06) for TTM-33 and 25.04mg (13.13–84.19) for TTM-36. Twenty-eight patients in TTM-33 and 15 in TTM-36 experienced shivering. The median and mode of BSAS score was 1 for both groups. Eleven (18.97%) patients received shivering prophylaxis with scheduled acetaminophen. Meperidine was administered in 22 out of 35 (62.86%) patients who had BSAS of 2, while neuromuscular blockers (NMB) were administered in seven out of 16 (43.75%) who had BSAS of 3. Three (42.86%) patients received NMB without a matching protocol BSAS.

Conclusions: More benzodiazepine and opioid amounts were used in TTM-33 compared to TTM-36. A higher propofol amount was used in TTM-36, relating to higher patients’ weight. More shivering occurred in TTM-33, and shivering management was not consistent with the hospital protocol with the low usage of prophylactic acetaminophen and NMB to manage BSAS of 3. With a recent study finding no differences between lower temperatures and normothermia for post-cardiac arrest, a normothermia target should require less sedation with lower shivering frequency. Nursing education should shift to focus on ensuring fever prevention and minimizing unnecessary sedation with the implementation of normothermia.