Case Report

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American Journal of Emergency Medicine

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Do we need to wait longer for cardiac arrest survivor to wake up in hypothermia era?

Abstract

Before the era of therapeutic hypothermia, a practice parameter including absent or extensor motor response at day 3 and the presence of myoclonus status epilepticus within 24 hours was used to assist prognostication of Poor neurologic outcomes. There are conflicting results concerning whether hypothermia influences the reliability of the predictors and the accurate predictors and optimal timing for assessing Neurologic recovery are largely unknown. Several prognostic indicators other than guidelines are also applied to help determining prognosis, including electroencephalogram, cerebral computed tomo- graphic scan, and cerebral perfusion scintigraphy single-photon emission computed tomographic scan. Here, we present a cardiac arrest survivor treated with therapeutic hypothermia waked up finally on the 13th day, although clinical and laboratory examinations after return of spontaneous circulation all indicated poor neurologic prognosis. However, life support was reported to be withdrawn within

3 to 5 days in 25% to 50% Cardiac arrest survivors treated with hypothermia when grave prognosis was predicted. The clinical course of the patient raises some important questions concerning the accuracy of current predictors, the optimal observation period for neurologic recovery, and the appropriate timing to determine withdrawal of life support in cardiac arrest victims receiving therapeutic hypothermia.

Although much effort devoted in improving the resuscitation and outcomes of cardiac arrest, the high mortality and poor neurologic outcomes in most survivors remain a big challenge for clinical physicians [1-3]. With the consideration of medical and financial resources, decisions about whether intensive care or supportive care often relay on the potential for these survivors to have meaningful neurologic recovery. With the introduction of therapeutic hypothermia, both the survival and neurologic outcomes improved in comatose survivors of cardiac arrest [4,5]. However, there is still a wide range of neurologic outcomes from totally clear to highly dependent statuses. It is still difficult to predict the exact neurologic outcome in early postcardiac arrest period.

The 58-year-old man was found to be acute conscious loss and pulseless by his daughter after poor appetite and malaise for several days. He had the history of diabetes, hypertension, and hepatitis B virus-related liver cirrhosis under regular medical follow-up. He had 1 episode of Traumatic head injury with intracranial hemorrhage and operation 7 years before the event, and occasional cognitive impairment was noted after the accident. Automated external defibrillator revealed ventricular fibrillation when emergency medical technician arrived, and 2 Electric shocks were given. The patient got return of spontaneous circulation (ROSC) at scene and then was sent the emergency department (ED).

In the ED, electrocardiogram, serum biochemistry, and transtho- racic echocardiography did not show evidence of acute coronary syndrome. Cerebral computed tomographic (CT) scan disclosed old

insults with parenchymal loss in bilateral anterior frontal lobe, posterior frontal lobe, and bilateral temporal poles and brain atrophy with dilated sulci, fissures, and ventricles (Fig. A). Therapeutic hypothermia with target temperature of 32?C for 24 hours was applied. myoclonic jerk was found after hypothermia completed. The electroencephalography (EEG) performed 5 days following ROSC showed diffuse cortical dysfunction and cerebral perfusion scintigra- phy single-photon emission CT (SPECT) scan performed 7 days following ROSC showed large areas of severe hypoperfusion to right frontal and right temporal lobes, moderate hypoperfusion to left frontal, left parietal, and left temporal lobes (Fig. B). Although all the parameters indicated a poor neurologic outcome, the patient finally waked up with clear consciousness on the 13th day following ROSC. He received successful extubation on the 40th day after cardiac arrest and transferred to the general ward smoothly.

Before the era of therapeutic hypothermia, the American Academy of Neurology established a practice parameter to assist prognostication of poor neurologic outcomes, including absent pupillary or corneal reflexes at day 3 after cardiac arrest, absent or extensor motor response at day 3, absent N20 response of somatosensory evoked potentials on days 1 to 3, serum neuron-specific enolase greater than 33 ng/mL at days 1 to 3, and the presence of myoclonus status epilepticus within 24 hours [6]. There are conflicting results concerning whether hypother- mia influences the reliability of the predictors, and the accurate predictors and optimal timing for assessing neurologic recovery are largely unknown [7-9]. The use of different sedatives during hypother- mia was proposed to contribute to the discrepancy [10].

Several prognostic indicators other than guidelines are also applied to help determining prognosis, including EEG, cerebral CT scan, and cerebral perfusion scintigraphy SPECT scan [8,11]. Malig- nant EEG and global Brain edema on CT are associated with poor prognosis [8]. By using cerebral SPECT scan performed at 24 hours following ROSC, Roine et al [11] reported larger Perfusion defect in comatose survivors and died victims of cardiac arrest when compared with survivors with good neurologic recovery [12]. In our patient, myoclonus was noticed after discontinue of muscular relaxant for therapeutic hypothermia, and the results of EEG, cerebral CT scan, and cerebral SPECT scan all indicated poor neurologic prognosis. However, the patient waked up on the 13th day following ROSC.

In the cardiac arrest survivors treated with hypothermia, the median and mean days of withdrawal of life support based on the grave Neurologic assessment and critical illness were reported to be 4 and 5, respectively [8]. A retrospective study disclosed that, of patients who received therapeutic hypothermia following cardiac arrest and were considered poor prognosis, 25% had life support withdrawn within 72 hours, and 21% survived to hospital discharge with favorable neurologic recovery [12]. These findings and our patient raise important questions concerning the accuracy of current

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Fig. A, Cerebral CT scan following ROSC disclosed old insults with parenchymal loss in bilateral anterior frontal lobe, posterior frontal lobe, and bilateral temporal poles and brain atrophy with dilated sulci, fissures, and ventricles. B, Cerebral SPECT on the seventh day after cardiac arrest showed large areas of severe hypoperfusion to right frontal and right temporal lobes, moderate hypoperfusion to left frontal, left parietal, and left temporal lobes, and mild hypoperfusion to right parietal, bilateral occipital lobes, left cerebellum, thalami, and pons.

predictors, the optimal observation period for neurologic recovery, and the appropriate timing to determine withdrawal of life support in cardiac arrest victims receiving therapeutic hypothermia.

With much effort devoted in predicting the prognosis earlier, maybe we can pay more patience to wait for them to wake up in hypothermia era because there is scanty and inconsistent results concerning whether therapeutic hypothermia affect the predictability and reliability of the current indicators.

Min-Shan Tsai MD, PhD

Department of Emergency Medicine National Taiwan University Hospital and College of Medicine

Taipei, Taiwan

Jo-Yu Chen MD

Department of Radiology National Taiwan University Hospital and College of Medicine

Taipei, Taiwan

Wen-Jone Chen MD, PhD Chien-Hua Huang MD, PhD Department of Emergency Medicine

National Taiwan University Hospital and College of Medicine

Taipei, Taiwan E-mail address: [email protected]

http://dx.doi.org/10.1016/j.ajem.2012.12.023

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