Elsevier

Resuscitation

Volume 84, Issue 12, December 2013, Pages 1741-1746
Resuscitation

Clinical paper
Time to awakening and neurologic outcome in therapeutic hypothermia-treated cardiac arrest patients,☆☆

https://doi.org/10.1016/j.resuscitation.2013.07.009Get rights and content

Abstract

Introduction

Therapeutic hypothermia (TH) has been shown to improve outcomes in comatose Post-Cardiac Arrest Syndrome (PCAS) patients. It is unclear how long it takes these patients to regain neurologic responsiveness post-arrest. We sought to determine the duration to post-arrest awakening and factors associated with times to such responsiveness.

Methods

We performed a retrospective chart review of consecutive TH-treated PCAS patients at three hospitals participating in a US cardiac arrest registry from 2005 to 2011. We measured the time from arrest until first documentation of “awakening”, defined as following commands purposefully.

Results

We included 194 consecutive TH-treated PCAS patients; mean age was 57 ± 16 years; 59% were male; 40% had an initial shockable rhythm. Mean cooling duration was 24 ± 8 h and mean rewarming time was 14 ± 13 h. Survival to discharge was 44%, with 78% of these discharged with a good neurologic outcome. Of the 85 patients who awakened, median time to awakening was 3.2 days (IQR 2.2, 4.5) post-cardiac arrest. Median time to awakening for a patient discharged in good neurological condition was 2.8 days (IQR 2.0, 4.5) vs. 4.0 days (IQR 3.5, 7.6) for those who survived to discharge without a good neurological outcome (p = 0.035). There was no significant association between initial rhythm, renal insufficiency, paralytic use, post-arrest seizure, or location of arrest and time to awakening.

Conclusion

In TH-treated PCAS patients, time to awakening after resuscitation was highly variable and often longer than three days. Earlier awakening was associated with better neurologic status at hospital discharge.

Introduction

Sudden cardiac arrest (SCA) affects approximately 300,000 people annually in the U.S. with a survival rate of <10% at hospital discharge [1] and significant long-term neurologic deficits in up to 50% of survivors [2], [3]. Both SCA patients who suffer such deficits and those who regain meaningful neurologic function generally remain comatose for days post-arrest, often secondary to anoxic encephalopathy and complicated by pharmacologic interventions. Consequently, a consensus statement put forth by the American Academy of Neurology (AAN) in 2006 addressing the value of prognostic indicators in SCA patients, recommends delaying neuroprognostication for at least 72 h post-arrest [2]. Recent innovations have altered the approach to post-arrest care, particularly the use of therapeutic hypothermia (TH) [4], [5], [6], [7], [8], [9], requiring reassessment of the applicability of the AAN recommendation [10], [11], [12], [13], [14].

In this investigation, our primary outcome was time to awakening in comatose post-cardiac arrest syndrome (PCAS) patients treated with TH. The secondary outcome examined neurologic function at discharge, described by Cerebral Performance Category (CPC) score. Several clinical factors were identified that might influence time to awakening, including medications administered, comorbid conditions, and seizure. We hypothesized that patients who survive with good neurologic function will have a shorter time to awakening than those who survive with poor neurologic function. Further, we sought to investigate whether patient-level factors (age, sex, race, renal sufficiency) or arrest-level factors (initial rhythm, location of arrest) were associated with time to awakening.

Section snippets

Methods

We utilized SCA data from the Penn Alliance for Therapeutic Hypothermia (PATH) database, an internet-based registry hosted at the University of Pennsylvania. The PATH database includes SCA data in the pre-hospital, emergency department, and in-hospital settings, focusing on post-arrest care, particularly TH. Open to any U.S. institution, it tracks all patients who experience SCA and receive cardiopulmonary resuscitation. This investigation received approval from the University of Pennsylvania

Results

During the study period, 201 consecutive PCAS patients were treated with TH via a standardized post-arrest protocol. Seven patients were excluded because of a primary neurologic arrest etiology, leaving a final cohort of 194. The mean age was 57 ± 16 years; 114/194 (59%) were male; 76/190 (40%) had VF/VT as an initial arrest rhythm. Forty-four percent (85/194) survived to hospital discharge, with 78% (66/85) of these patients discharged with CPC 1–2 (Table 1). Of the 44% (85/194) who awakened,

Discussion

In a cohort of 194 comatose TH-treated PCAS patients, shorter time to awakening was significantly associated with better neurologic outcome. Time to awakening was not associated with age, sex, race, initial rhythm, ESRD, paralytic use, seizure, or location of arrest.

Our results are consistent with a prior small single-center investigation of post-arrest patients treated with TH. In a cohort of 47 out-of-hospital arrests, Eid et al. found that meaningful awakening, defined as CPC 1–2, could

Conflict of interest statement

Ms. Leary has served as a consultant for Stryker Corporation. Dr. Abella receives research support from NHLBI, Phillips Healthcare, Medtronic Inc., and the Doris Duke Foundation, has received honoraria from Medivance Corporation, and serves as a consultant to Velomedix Inc. and serves on the medical advisory board for HeartSine Technologies Inc. Dr. Gaieski has received research support, receives honoraria, and has served as a consultant for Stryker Corporation.

References (29)

  • R.A. Berg et al.

    Part 5: adult basic life support: 2010. American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

    Circulation

    (2010)
  • J. Arrich et al.

    Clinical application of mild therapeutic hypothermia after cardiac arrest

    Crit Care Med

    (2007)
  • N. Nielsen et al.

    Outcome, timing and adverse events in therapeutic hypothermia after out-of-hospital cardiac arrest

    Acta Anaesthesiol Scand

    (2009)
  • E. Sagalyn et al.

    Therapeutic hypothermia after cardiac arrest in clinical practice: review and compilation of recent experiences

    Crit Care Med

    (2009)
  • Cited by (85)

    • Initial arterial pH as a predictor of neurologic outcome after out-of-hospital cardiac arrest: A propensity-adjusted analysis

      2019, Resuscitation
      Citation Excerpt :

      TTM is recommended for 24 h at 32–36 °C regardless of arrest rhythm,3 a guideline supported by randomized control trial4–6 and meta-analysis7–9 data. In TTM-treated OHCA patients, current recommendations are to delay neurologic prognostication >72 h post-arrest,3,10 a timeline consistent with reported average awakening 3.2 days post-OHCA.11 Nevertheless, the majority of patients will not recover meaningful neurologic function.

    View all citing articles on Scopus

    A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2013.07.009.

    ☆☆

    This manuscript was supported by unrestricted funding for the Penn Alliance for Therapeutic Hypothermia (PATH) database, provided by Stryker Industries.

    View full text