Clinical examination for prognostication in comatose cardiac arrest patients

Abstract

Objective: To build new algorithms for prognostication of comatose cardiac arrest patients using clinical examination, and investigate whether therapeutic hypothermia influences the value of the clinical examination.

Methods: From 2000 to 2007, 500 consecutive patients in non-traumatic coma were prospectively enrolled, 200 of whom were post-cardiac arrest. Outcome was determined by modified Rankin Scale (mRS) score at 6 months, with mRS≤3 indicating good outcome. The clinical examination was performed on days 0, 1, 3 and 7 post-arrest, and clinical variables analyzed for importance in prognostication of outcome. A classification and regression tree analysis (CART) was used to develop a predictive algorithm.

Results: Good outcome was achieved in 9.9% of patients. In CART analysis, motor response was often chosen as a root node, and spontaneous eye movements, pupillary reflexes, eye opening and corneal reflexes were often chosen as splitting nodes. Over 8% of patients with absent or extensor motor response on day 3 achieved a good outcome, as did 2 patients with myoclonic status epilepticus. The odds of achieving a good outcome were lower in patients who suffered asystole (OR 0.187, 95% CI: 0.039-0.875, p=0.033) compared with ventricular fibrillation or non-perfusing ventricular tachycardia, but some still achieved good outcome. The absence of pupillary and corneal reflexes on day 3 remained highly reliable for predicting poor outcome, regardless of therapeutic hypothermia utilization.

Conclusion: The clinical examination remains central to prognostication in comatose cardiac arrest patients in the modern area. Future studies should incorporate the clinical examination along with modern technology for accurate prognostication.

Keywords: Cardiac arrest; Coma; Neurologic examination; Outcome; Prognosis.

Fig. 1

Prediction of outcome in comatose cardiac arrest patients using Levy et al.’s algorithm. No patients achieved a mRS score of 4; therefore no separate column for this outcome is presented. Numbers in () represent 95% confidence intervals. Numbers in [] represent the number reported in the Levy et al. study. (A) Day 0, (B) Day 1, (C) Day 3, (D) Day 7.

Fig. 2

Prediction of outcome in comatose cardiac arrest patients using CART analysis. Note that the number of patients is low on day 7, making the findings less reliable at this time point. OVR, oculovestibular reflex; eye opening = spontaneous eye opening. (A) Day 0, (B) Day 1, (C) Day 3, (D) Day 7.