Resuscitation 85 (2014) e183–e184

Contents lists available at ScienceDirect

Resuscitation journal homepage: www.elsevier.com/locate/resuscitation

Letter to the Editor False positive absent somatosensory evoked potentials in cardiac arrest with therapeutic hypothermia Dear Sir, Arch et al.1 recently described the case of a young patient with a good neurological outcome despite the finding of a bilateral absent cortical response on median nerve somatosensory evoked potentials (SSEP) 49 h after a cardiac arrest treated with therapeutic hypothermia (TH). The case is interesting because it questions the reliability of SSEP in predicting poor neurological outcome after the introduction of TH. To increase the reliability of SSEP, the Authors advise to wait at least 72 h before performing the recording. We present a case of false positive SSEP which suggests that this 72 h time-limit may still not be sufficient. A 34-year-old drug-addict male underwent a cardiac arrest after cocaine and heroin overdose. Initial rhythm was asystolia and after resuscitation the patient arrived at our hospital with a Glascow

Coma Scale of 4/15 and symmetrical, sluggish reactive pupils. TH was initiated 2 h after cardiac arrest with a target temperature of 33 ◦ C for 24 h. It was not possible to carry out SSEP immediately, due to logistical issues, so they were performed about 84 h after the cardiac arrest disclosing a bilateral absent cortical response (Fig. 1A). In agreement with the family’s will, supportive therapy was not withdrawn and during the following days the patient experienced a progressive recovery of consciousness. A further SSEP examination, performed on the 13th day after cardiac arrest recorded a bilateral cortical response with latency and amplitude within the normal limits (Fig. 1B). The patient was transferred to a rehabilitation facility, where he was discharged a few months later with a normal neurological examination. Our case confirms that the finding of a bilateral absent cortical response should be considered with caution in estimating a poor prognosis in patients treated with TH. Indeed, even though SSEP are considered to be reliable even in patients treated with TH,2 there are some concerns related to reports of false positive cases

Fig. 1. (A) Median nerve somatosensory evoked potentials recorded 84 h after cardiac arrest, derivations are from top to bottom: Erb’s point ipsilateral – Erb’s point controlateral, C3 –C4 (for right side stimulation) and C4 –C3 (for left side stimulation). Time calibrations are 5 ms per division, amplitude calibrations in microvolts are respectively 2.0 and 1.0 ␮V. (B) Somatosensory evoked potentials recorded on day 13 after cardiac arrest, derivations are from top to bottom: Erb’s point ipsilateral – Erb’s point controlateral, C7 – anterior cervical reference (Giug), C3 –C4 (for right side stimulation) and C4 –C3 (for left side stimulation). Time calibrations are 5 ms per division, amplitude calibrations in microvolts are respectively 2.0, 2.0 and 1.0 ␮V. http://dx.doi.org/10.1016/j.resuscitation.2014.08.012 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.

e184

Letter to the Editor / Resuscitation 85 (2014) e183–e184

such as ours. Our case raises even more concern due to the long time-interval between the cardiac arrest and the recording of a false positive result (84 h). We hypothesize that the status of active drugaddiction in our patient may have contributed to the prolonged absence of SSEP cortical responses. Chronic illicit drug abuse is indeed known to provoke dysfunction in brain connectivity3,4 and the brain of our patient could have been compromised by years of drug addiction, thus leading to a slower functional recovery after the metabolic storm provoked by cardiac arrest and TH. Moreover, our patient also presented an acute toxic brain injury provoked by the drug overdose which may have contributed to the impairment of normal brain activity. We agree with Arch et al.1 that it is useful to postpone SSEP recording in patients treated with TH, and we suggest to consider carefully a positive result if the patient has health disorders or concomitant neurotoxic conditions which can compromise brain functional recovery, such as chronic drug addiction or acute intoxications. Conflict of interest statement There are no conflict or competing interests. Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. References 1. Arch AE, Chiappa K, Greer DM. False positive absent somatosensory evoked potentials in cardiac arrest with therapeutic hypothermia. Resuscitation 2014;85:e97–8.

2. Sandroni C, Cavallaro F, Callaway CW, et al. Predictors of poor neurological outcome in adult comatose survivors of cardiac arrest: a systematic review and meta-analysis. Part 2. Patients treated with therapeutic hypothermia. Resuscitation 2013;84:1324–38. 3. Bora E, Yucel M, Fornito A, et al. White matter microstructure in opiate addiction. Addict Biol 2012;17:141–8. 4. Hanlon CA, Beveridge TJ, Porrino LJ. Recovering from cocaine: insight from clinical and preclinical investigations. Neurosci Biobehav Rev 2013;37:2037–46.

Luca Codeluppi ∗ Unit of Neurology, NOCSAE Hospital, University of Modena and Reggio Emilia, AUSL Modena, Modena, Italy Diana Ferraro Unit of Neurology, NOCSAE Hospital, University of Modena and Reggio Emilia, AUSL Modena, Modena, Italy Andrea Marudi Neurological Intensive Care Unit, Department of Emergency and Critical Care Medicine, NOCSAE Hospital, AUSL Modena, Modena, Italy Franco Valzania Unit of Neurology, NOCSAE Hospital, University of Modena and Reggio Emilia, AUSL Modena, Modena, Italy ∗ Corresponding author at: Nuovo Ospedale Civile Sant’Agostino Estense (NOCSAE), Via Giardini 1355, 41126 Modena, Italy. E-mail address: [email protected] (L. Codeluppi)

6 August 2014

False positive absent somatosensory evoked potentials in cardiac arrest with therapeutic hypothermia.

False positive absent somatosensory evoked potentials in cardiac arrest with therapeutic hypothermia. - PDF Download Free
396KB Sizes 0 Downloads 6 Views