Why a Propofol Infusion Should Be the Anesthetic of Choice for Auditory Brainstem Response Testing in Children

Abstract

BACKGROUND: Auditory brainstem response (ABR) testing is considered to be relatively resistant to effects of volatile anesthetics. The impact of newer anesthetics on interpretability of ABR testing is unknown. This study compared sevoflurane versus propofol anesthesia on qualitative interpretability of ABR click-testing in children. METHODS: This prospective double-blind crossover study enrolled children (≤18 years old) receiving general anesthesia for elective ABR testing. All subjects received both sevoflurane and propofol anesthesias in the same ABR testing session. Deidentified ABR data were reviewed by 5 audiologists (blinded to anesthetic and patient) to determine threshold levels for hearing loss. The primary outcome was qualitative interpretability (false positive) of ABR click-testing. RESULTS: Each patient was tested at 4 different intensities in each ear: generating 624 records under each anesthetic, for a total of 1248 records. A few patients were tested at 5 different intensities in a single ear accounting for the additional 11 records, yielding 1259 records. Under sevoflurane anesthesia, 21 of the same patients (37 ears) were identified with abnormal ABR levels consistent with hearing loss (one or both ears). The probability of a patient being diagnosed with hearing "loss" in one or both ears was significantly less with propofol versus sevoflurane anesthesia (mid P =.0312). If patients with bilateral loss are compared, the mid P value is 0.0098. The effect size based on patients was medium to large, with a minimum value of Cohen w = 0.320. CONCLUSIONS: Sevoflurane produced more false positives for hearing loss and suggested more severe hearing loss than propofol. False-positive ABR tests, produced by certain anesthetic agents, can have significant life-long impact and negative psychosocial and developmental implications. Use of the intravenous anesthetic propofol is superior to sevoflurane for ABR testing in children. (Anesth Analg 2022;134:802-9) KEY POINTS• Question: Does the anesthetic agent used during auditory brainstem response (ABR) testing for hearing impairment in children influence interpretability of results? • Findings: Sevoflurane produced more false positives for hearing loss and suggested more severe hearing loss than propofol. • Meaning: Anesthetic regimens can lead to significant alteration in interpretability of ABR testing children-use of sevoflurane may cloud interpretability, and propofol seems to be a preferable anesthetic agent. GLOSSARYABR = auditory brainstem response; ASA = American Society of Anesthesiologists; AUC = area under the curve; CONSORT = Consolidated Standards of Reporting Trials; D/C = discontinue; IV = intravenous; MAC = minimum alveolar concentration; nHL = normal adult hearing level; SVM = support vector machine versions of this article on the journal's website (www.anesthesia-analgesia. org).