Sedation Confounds Outcome Prediction in Cardiac Arrest Survivors Treated with Hypothermia

• Published in: Neurocritical care Vol. 15; no. 1; pp. 113 - 119
• Main Authors: Samaniego, Edgar A., Mlynash, Michael, Caulfield, Anna Finley, Eyngorn, Irina, Wijman, Christine A. C.
• Format: Journal Article
• Language: English
• Published: New York Humana Press Inc 01.08.2011; Springer Nature B.V
• Subjects: Adult; Aged; Aged, 80 and over; Anesthesia; Brain death; Cardiac arrest; Cardiac arrhythmia; Cardiopulmonary Resuscitation; Cardiovascular disease; Coma - diagnosis; Coma - etiology; Coma - therapy; Cooling; CPR; Critical Care Medicine; Female; Fentanyl; Heart Arrest - diagnosis; Heart Arrest - mortality; Heart Arrest - therapy; Humans; Hypnotics and Sedatives - therapeutic use; Hypothermia; Hypothermia, Induced; Intensive; Internal Medicine; Male; Medicine; Medicine & Public Health; Middle Aged; Neurology; Original Article; Patients; Persistent Vegetative State - diagnosis; Persistent Vegetative State - etiology; Persistent Vegetative State - therapy; Predictive Value of Tests; Prognosis; Prospective Studies; Young Adult; United States > US; Coma; Prognosis; Cardiac arrest; Somatosensory-evoked potential; Sedation; Status myoclonus; Hypothermia; Neuron-specific enolase
• ISSN: 1541-6933; 1556-0961
• DOI: 10.1007/s12028-010-9412-8

Background Therapeutic hypothermia is commonly used in comatose survivors’ post-cardiopulmonary resuscitation (CPR). It is unknown whether outcome predictors perform accurately after hypothermia treatment. Methods Post-CPR comatose survivors were prospectively enrolled. Six outcome predictors [pupillary and corneal reflexes, motor response to pain, and somatosensory-evoked potentials (SSEP) >72 h; status myoclonus, and serum neuron-specific enolase (NSE) levels <72 h] were systematically recorded. Poor outcome was defined as death or vegetative state at 3 months. Patients were considered “sedated” if they received any sedative drugs ≤12 h prior the 72 h neurological assessment. Results Of 85 prospectively enrolled patients, 53 (62%) underwent hypothermia. Furthermore, 53 of the 85 patients (62%) had a poor outcome. Baseline characteristics did not differ between the hypothermia and normothermia groups. Sedative drugs at 72 h were used in 62 (73%) patients overall, and more frequently in hypothermia than in normothermia patients: 83 versus 60% ( P  = 0.02). Status myoclonus <72 h, absent cortical responses by SSEPs >72 h, and absent pupillary reflexes >72 h predicted poor outcome with a 100% specificity both in hypothermia and normothermia patients. In contrast, absent corneal reflexes >72 h, motor response extensor or absent >72 h, and peak NSE >33 ng/ml <72 h predicted poor outcome with 100% specificity only in non-sedated patients, irrespective of prior treatment with hypothermia. Conclusions Sedative medications are commonly used in proximity of the 72-h neurological examination in comatose CPR survivors and are an important prognostication confounder. Patients treated with hypothermia are more likely to receive sedation than those who are not treated with hypothermia.