Cerebral Performance Category at Hospital Discharge Predicts Long-Term Survival of Cardiac Arrest Survivors Receiving Targeted Temperature Management*

Abstract

Objective Despite recent advancements in post-cardiac arrest resuscitation, the optimal measurement of post-arrest outcome remains unclear. We hypothesized that cerebral performance category (CPC) score can predict the long-term outcome of post- arrest survivors who received targeted temperature management (TTM) during their post-arrest hospital care. Design Retrospective chart review. Setting Two academic medical centers from May, 2005 to December, 2012. Patients The medical records of 2,417 out-of-hospital and in-hospital post-cardiac arrest patients were reviewed to identify 140 out of 582 survivors who received TTM. Interventions None. Measurements and Main Results The CPC scores at hospital discharge were determined by three independent abstractors. The 1-month, 6-month, and 12-month survival of these patients were determined by reviewing hospital records, querying the Social Security Death Index, and follow-up telephone calls. The unadjusted long-term survival and adjusted survival association with CPC were calculated. Of the 2,417 identified cardiac arrest patients, 24.1% (582/2417) were successfully resuscitated, of whom 24.1% (140/582) received post-arrest TTM. Overall, 42.9% (60/140) were discharged with CPC 1, 27.1% (38/140) with CPC 2, 18.6% (26/140) with CPC 3, and 11.4% (16/140) with CPC 4. CPC 1 survivors had the highest long-term survival followed by CPC 2 and 3, with CPC 4 having the lowest long-term survival (p < 0.001, log-rank test). We found that CPC 3 (hazard ratio = 3.62, p < 0.05) and CPC 4 (hazard ratio = 12.73, p <0.001) remained associated with worse survival after adjusting for age, gender, race, shockable rhythm, time to TTM initiation, total duration of resuscitation, withdrawal of care, and location of arrest. Conclusion Patients with different CPC scores at discharge have significantly different survival trajectories. Favorable CPC at hospital discharge predicts better long-term outcomes of cardiac arrest survivors who received TTM than those with less favorable CPC scores.

Inter-rater reliability of post-arrest cerebral performance category (CPC) scores

“…Despite its limitations, the CPC score at hospital discharge was shown in two studies, one in all patients treated with TTM 19 and one in patients experiencing OHCA, 20 to predict long-term survival outcomes in post-arrest patients, with favorable CPC scores associated with a greater likelihood of long-term survival. 19,20 Recently, the construct validity of the CPC score was assessed with the conclusion that a CPC can be used to measure functional outcome, particularly when administered as a standardized interview.…”

“…19,20 Recently, the construct validity of the CPC score was assessed with the conclusion that a CPC can be used to measure functional outcome, particularly when administered as a standardized interview. 7 Although 23% of raw CPC scores and 12% of dichotomized CPC were discordant in this study, they still showed substantial agreement in inter-rater reliability overall.…”

Is Neurologic Prognostication After Hypothermia Ready for Primetime?*

“…The important and noteworthy feature of this study is the fact that they looked exclusively at patients treated with hypothermia. This significantly highlights the importance of the research focus on hypothermia and also explains the slightly low sample size as only a fraction of post-cardiac arrest patients are treated with TTM (24.1%, 140/582 in this study) (9). Other studies correlating CPC with long-term survival after cardiac arrest included a mix of patients treated with and without TTM, introducing uncertainty regarding the validity of their results in cooled patients (10, 11).…”

“…In this edition of Critical Care Medicine , Hsu et al adds to the growing body of literature that examines predictors of prognosis in cardiac arrest patients treated with therapeutic hypothermia (9). In their study of patients treated with targeted temperature management (TTM) of 33 to 34°C after cardiac arrest, the authors reported that good Cerebral Performance Category (CPC) scores at hospital discharge predicted longer patient survival.…”

“…The present study’s choice of using the CPC score as the prognostic marker has its advantages as well as drawbacks (9). The CPC score has been widely used in the cardiac arrest literature, and is relatively easy to estimate and interpret, though typically as an outcome measure (however intermediate) rather than a prognostic marker.…”