Prognostic value of somatosensory-evoked potentials in the newborn with hypoxic-ischemic encephalopathy after the introduction of therapeutic hypothermia

Abstract

To establish the ability of somatosensory-evoked potentials (SEPs) to detect neurological damage in neonatal patients with hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia (TH). Retrospective study including 84 neonates ≥ 36 weeks of gestational age with HIE and TH with SEPs performed in the first 14 days of life. SEPs from the median nerve were performed after completion of TH. Either unilateral or bilateral absence of N20, or unilateral or bilateral latency ≥ 36 ms, was considered pathological. All newborns underwent a cerebral resonance imaging (MRI) at between days 7 and 14 of life and a neurodevelopmental evaluation using the Brunet-Lezine test at two years of age; a global Brunet-Lezine test score < 70 was considered unfavorable. The risk of moderate-to-severe alteration on basal ganglia-thalamic (BGT) and/or white matter areas on MRI for pathological SEPs was as follows: odds ratio 95% IC: 23.1 (6.9-76.9), sensitivity 78.6%, specificity 86.3%, positive predictive value 75.9%, and negative predictive value 88%. The BGT and internal capsule were the areas with the greatest risk of lesion with an altered SEPs: odds ratio 95% IC 93.1 (11.1-777.8). The risk of neurodevelopmental impairment for pathological SEPs was odds ratio 95% IC: 38.5 (4.4-335.3), sensitivity 91.7%, specificity 77.8% positive predictive value 52.4%, and negative predictive value 97.2%.

Conclusion: The present study demonstrates the good predictive capacity of SEPs performed in the first two weeks of life in newborns with HIE and TH to detect an increased risk of neuroimaging lesions and neurodevelopmental impairment at two years of age.

What is known: • Bilateral absence of the N20 cortical component of somatosensory evoked potentials has been associated with poor neurological outcome in neonates with hypoxic-ischemic encephalopathy.

What is new: • This work confirms the predictive capacity of SEPs by adding two important aspects: the value of latency when interpreting SEPs results and the absence of effect of the hypothermia method used on the results of SEPs.

Keywords: Asphyxia; Brain monitoring; Hypoxic-ischemic encephalopathy; Newborn; Somatosensory-evoked potentials; Therapeutic hypothermia.