Elsevier

Resuscitation

Volume 103, June 2016, Pages 7-13
Resuscitation

Clinical paper
The optic nerve sheath diameter as a useful tool for early prediction of outcome after cardiac arrest: A prospective pilot study

https://doi.org/10.1016/j.resuscitation.2016.03.006Get rights and content

Abstract

Introduction

Optic nerve sheath diameter (ONSD) measurement could detect increased intracranial pressure, and might predict outcome in post-cardiac arrest (CA) patients. We assessed the ability of bedside ONSD ultrasonographic measurement performed within day 1 after CA occurrence to predict in-hospital survival in patients treated with therapeutic hypothermia (TH).

Methods

In two French ICUs, a prospective study included all consecutive patients with CA without traumatic or neurological etiology, successfully resuscitated and TH-treated. ONSD measurements were performed on day 1, 2, and 3 (ONSD1, 2, 3 respectively) after return of spontaneous circulation. All records were registered according to Utstein style.

Results

ONSD1, 2, 3 were assessed in 36, 21, and 14 patients respectively. 19/36 patients (53%) were discharged alive from hospital, including 14/36 (39%) with favorable neurological outcome (Cerebral Performance Category [CPC] score 1–2). Survivors and non-survivors were similar regarding age, sex, cardiovascular risk factors, location and etiology of CA, simplified acute physiology score II, occurrence of post-CA shock, and clinical parameters collected during ONSD measurements. Median ONSD1 was significantly larger in non-survivors versus survivors (7.2 mm [interquartile: 6.8–7.4] versus 6.5 mm [interquartile: 6.0–6.8]; p = 0.008). After adjustment on predictive factors, ONSD1 was significantly associated with in-hospital mortality (OR 6.3; 95%CI [1.05–40] per mm of ONSD1 above 5.5 mm; p = 0.03), and CPC score (OR for 1 point increase in CPC score: 3.2; 95%CI [1.2–9.4] per mm of ONSD1 above 5.5 mm; p = 0.03). ONSD1 was significantly correlated with brain edema assessed by the cerebrum gray matter attenuation to white matter attenuation ratio, measured by the brain computed tomography scan performed on admission in 20 patients (Spearman rho = −0.5, p = 0.04).

Conclusions

ONSD seems a promising tool to early assess outcome in post-CA patients treated with TH.

Introduction

In resuscitated cardiac arrest (CA) patients, early prognostication within the first days after admission in the intensive care unit (ICU) remains difficult, especially among patients treated with therapeutic hypothermia (TH). Clinical examination, neurological biomarkers, and electrophysiological evaluations can be used, mainly in combination.1, 2, 3 The out-of-hospital cardiac arrest (OHCA) score has also been used to predict outcome.4 According to recent guidelines, a multimodal neuroprognostication approach is recommended, but no specific combination of predictors is sufficiently supported by available evidence.1, 5

In CA as in traumatic brain injury (TBI), anoxic and/or ischemic brain injuries can induce brain edema and increase intracranial pressure (ICP), reducing cerebral perfusion pressure and finally influencing neurological outcome.6, 7, 8, 9, 10 The dural sheath that surrounds the optic nerve can inflate if pressure in the cerebrospinal fluid raised, as it occurs in brain edema or intracranial hypertension.11 As invasive ICP monitoring showed a good correlation with optic nerve sheath diameter (ONSD) measurement, ONSD measurement has been used to detect increased ICP level in TBI.12, 13 Two retrospective studies observed that ONSD measured between 12 and 72 h after CA might be used for assessing neurological outcome.14, 15 The relationship between an early ONSD ultrasonographic measurement and CA outcome has never been prospectively evaluated after adjustment on known predictive factors. The aim of this prospective clinical pilot study was to assess the ability of ONSD ultrasonographic measurement performed within day 1 after CA occurrence to correctly predict in-hospital mortality in post-CA patients treated with TH.

Section snippets

Materials and methods

This prospective observational study was performed in two French ICUs from November 2011 to September 2013. All unconscious (Glasgow Coma Scale ≤6) patients ≥18 years old, admitted in ICU after successful resuscitation from CA, and treated with TH were screened. Exclusion criteria were as follows: unavailable ONSD measurement within 24 h after CA (unavailable investigator, early death, or major hemodynamic instability), CA of traumatic or neurological origin, previous cerebrovascular disease,

Patients’ characteristics

Ninety-four patients were assessed for eligibility and 58 were excluded (Fig. 1). Among the 36 enrolled patients, 19 patients (53%) were discharged alive from hospital, with favorable neurological outcome occurring in 14 patients (39%). Among the 17 patients who died in ICU, 11 patients died from withdrawal or limitation of life-sustaining treatments (WLST) because of severe neurological impairment. Three other patients evolved to brain death, and the three remaining patients died from multiple

Discussion

Our main findings can be summarized as follows: 1/in CA patients successfully resuscitated and treated with TH, a larger ONSD1 is associated with higher in-hospital mortality and worst neurological outcome assessed by the CPC score; 2/ONSD1 measurement is correlated with brain edema as measured by GWR on early brain CT scan, and with NSE on ICU admission and at day 1; 3/interestingly, all three patients who subsequently evolved to brain death had a very high ONSD1 value (≥7.2 mm).

Conclusions

To conclude, our study confirms that ONSD ultrasonographic measurement within the first 24 h after CA is a promising way to evaluate the severity of post-CA brain injuries and outcome in a multimodal neuroprognostication approach. This non-invasive bedside tool is simple, cheap, available for serial measurements, and correlated to brain edema, NSE axonal biomarkers, CPC score and survival. Further multicentre studies are warranted to confirm ours results.

Conflict of interest statement

The authors received no financial support for this work. None of the authors have any financial and non-financial competing interests in relation with this paper.

Acknowledgment

We thank Professor FJ Baud for his critical analysis of the study.

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    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.2016.03.006.

    1

    These authors contributed equally to this work and are considered as the 2 first co-authors.

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