Elsevier

Resuscitation

Volume 113, April 2017, Pages 39-43
Resuscitation

Clinical paper
Changing target temperature from 33 °C to 36 °C in the ICU management of out-of-hospital cardiac arrest: A before and after study

https://doi.org/10.1016/j.resuscitation.2017.01.016Get rights and content

Abstract

Introduction

In December 2013, our institution changed the target temperature management (TTM) for the first 24 h in ventricular fibrillation out-of-hospital cardiac arrest (VF-OHCA) patients from 33 °C to 36 °C. This study aimed to examine the impact this change had on measured temperatures and patient outcomes.

Methods

We conducted a retrospective cohort study of consecutive VF-OHCA patients admitted to a tertiary referral hospital in Melbourne (Australia) between January 2013 and August 2015. Outcomes were adjusted for age and duration of cardiac arrest.

Results

Over the 30-month period, 76 VF-OHCA cases were admitted (24 before and 52 after the TTM change). Patient demographics, cardiac arrest features and hospital interventions were similar between the two periods. After the TTM change, less patients received active cooling (100% vs. 70%, p < 0.001), patients spent less time at target temperature (87% vs. 50%, p < 0.001), and fever rates increased (0% vs. 19%, p = 0.03). ​During the 36 °C period, there was a decrease in the proportion of patients who were discharged: alive (71% vs. 58%, p = 0.31), home (58% vs. 40%, p = 0.08); and, with a favourable neurological outcome (cerebral performance category score 1-2: 71% vs. 56%, p = 0.22).

Conclusion

After the change from a TTM target of 33 °C to 36 °C, we report low compliance with target temperature, higher rates of fever, and a trend towards clinical worsening in patient outcomes. Hospitals adopting a 36 °C target temperature to need to be aware that this target may not be easy to achieve, and requires adequate sedation and muscle-relaxant to avoid fever.

Introduction

Since the publication of two seminal studies1, 2 over a decade ago, therapeutic hypothermia (32 °C–34 °C) for at least 24 h has been recommended in the post-resuscitation care for comatose survivors of cardiac arrest.3, 4 More recently, the recommended targeted temperature for this treatment was expanded from a range of 32–34 °C to 32–36 °C5, 6 following results from the targeted temperature management (TTM) trial.7 The TTM trial allocated patients to either 32–34 °C or 36 °C, and found no difference in outcomes.

Following publication of the TTM trial, many centres have adopted a target temperature of 36 °C.8, 9, 10 However, achieving a target temperature of 36 °C may be problematic, with a recent study reporting a significant risk of fever in the first 24 h of ICU admission.11

In December 2013, the intensive care unit (ICU) at The Alfred Hospital changed the post-resuscitation target temperature for ventricular fibrillation out-of-hospital cardiac arrest (VF-OHCA) patients from 33 °C to 36 °C. This paper presents the findings of a retrospective cohort study of patients admitted before and after this change which examined compliance with the targeted temperature and patient outcomes.

Section snippets

Setting

This study was performed on consecutive, non-traumatic, VF-OHCA patients admitted to The Alfred Hospital ICU (Melbourne, Australia) between January 2013 and August 2015. The Alfred Hospital is a quaternary referral hospital in Melbourne, Australia, with cardiac services including interventional cardiology, extra-corporeal membrane oxygenation (ECMO) and cardiac transplantation.12 This study was approved by The Alfred Hospital Human Research and Ethics Committee.

Ambulance response to OHCA

Results

Over the study period, 76 VF-OHCA cases were admitted to the ICU (24 before and 52 after the TTM change). Patient demographics and cardiac arrest features were similar between the two periods (Table 1). The overall median time from cardiac arrest to return of spontaneous circulation (ROSC) was similar between the two periods (20 vs. 22 min, p = 0.98).

A similar number of patients underwent urgent cardiac catheterisation, but there were more patients treated with veno-arterial ECMO in the 33 °C

Discussion

The change from a post-arrest temperature target of 33 °C to 36 °C in our ICU has been associated with significant non-compliance with achieving the target temperature and this may be associated with poorer patient outcomes. Our results are noteworthy given that many ICUs have changed TTM practice.8, 9, 10 For example, a recent 10-year audit of ICUs in the United Kingdom reported a sudden drop in 2014 to the proportion of cardiac arrest patients with a lowest temperature recording of <34 °C (39%

Conflict of interest statement

None.

Acknowledgements

Drs Bray (#1069985), Stub (#1090302) and Mitra (#1072579) are supported by National Health and Medical Research (NHMRC)/Heart Foundation Fellowships. Dr Bray and Prof Finn receive salary support from the Australian Resuscitation Outcomes Consortium (Aus-ROC) NHMRC funded Centre of Research Excellence (#1029983).

References (16)

There are more references available in the full text version of this article.

Cited by (122)

  • Neurocritical Care in the General Intensive Care Unit

    2023, Critical Care Clinics
    Citation Excerpt :

    Early priority is effective post-CA care to identify and treat the precipitating cause of arrest, and to prevent rearrest.1 The flow chart (Fig. 1) summarizes our approach to post-CA management.1–26 Patients who achieve ROSC should be rapidly evaluated for coronary intervention and targeted temperature management (TTM) to prevent secondary brain injury.

View all citing articles on Scopus

A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2017.01.016.

View full text