title: Brain-stem auditory evoked responses to hypercarbia in preterm infants.
abstract: To determine the effect of acute hypercarbia on brain-stem function in preterm neonates, we compared brain-stem auditory evoked responses (BAERs) during 8% CO2 breathing to those elicited during room air breathing in 12 healthy preterm infants during the first week of life. End-tidal CO2 (ETpCO2), respiratory rate and depth were monitored throughout the protocol. Absolute wave latencies and interpeak intervals of the BAERs were analyzed from duplicate trials. During 8% CO2 breathing, ETpCO2, respiratory rate and depth of respiration increased significantly (P < 0.05). The absolute latency of wave V was prolonged (P < 0.025) in the hypercarbic state as compared to baseline. Interpeak interval III-V was also prolonged (P < 0.025). Values of absolute peak latencies I and III were unaffected by the hypercarbic state. These data demonstrate that elevations in pCO2 which elicit ventilatory responses also effect the BAER. The specific effects on ventilatory pattern, peak V latency and interpeak interval III-V indicate brain-stem responsiveness and alterations in the more central components of the auditory pathway. These findings raise important considerations regarding the influence of hypercarbia on brain-stem function in preterm infants and the clinical management of such infants with abnormalities of gas exchange.
authors.affiliation: Department of Pediatrics, Temple University School of Medicine, Philadelphia, PA.
authors.forename: H E
authors.initials: HE
authors.lastname: Friss
authors.forename: D
authors.initials: D
authors.lastname: Wavrek
authors.forename: W H
authors.initials: WH
authors.lastname: Martin
authors.forename: M R
authors.initials: MR
authors.lastname: Wolfson
mesh_terms: D000280:Administration, Inhalation; D002245:Carbon Dioxide / Q000627:therapeutic use; D016057:Evoked Potentials, Auditory, Brain Stem; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology* / Q000628:therapy; D007231:Infant, Newborn; D007234:Infant, Premature; D011930:Reaction Time; D012119:Respiration
chemical_list: D002245:Carbon Dioxide