Abstract:OBJECTIVE: To study the effect of selective moderate head cooling therapy on maximum length sequences brainstem auditory evoked potential (MLS-BAEP) in newborn piglets with hypoxic-ischemic brain damage. METHODS: Sixteen newborn piglets aged 5-7 day old were randomly divided into three groups: normothermic control (n=4), HI (n=6) and mild hypothermia-treated (n=6). HI was induced through temporary occlusion of both carotid arteries, followed by mechanical ventilation with low concentration of oxygen (FiO2=0.06) for 30 minutes. Mild hypothermia was induced by equipment via circulating water. MLS-BAER was recorded before HI and at 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, 4 days, 7 days, 10 days, 13 days and 15 days after HI. RESULTS: Compared with the normothermic control group, all latencies and intervals tended to increase significantly at 72 hours in the HI group and reached peak values on day 7. From day 10, all latencies and intervals tended to decrease, but apart from wave I latency, still differed significantly from those of the normothermic control group. MLS-BAER variables did not reach normal values until day 15. Ⅲ latency, Ⅰ-Ⅲ interval and Ⅰ-Ⅴ interval were significantly reduced in the hypothermia-treated group between 60 and 7 days after HI compared with the HI group (P<0.05). V latency and Ⅲ-Ⅴ interval in the hypothermia-treated group were also reduced compared with the HI group between 72 hours and 7 days after HI (P<0.05). CONCLUSIONS: Both peripheral and central auditory systems are disturbed by HI, which shows as a significant increase in MLS-BAER variables (all latencies and intervals) in newborn piglets. Involement in central brainstem auditory system reaches a peak on day 7 after injury. MLS-BAER variables still cannot reach to normal values until day 15. Selective moderate head cooling therapy can significantly reduce brainstem damage induced by HI.
WANG Ji-Mei,ZHOU Wen-Hao,CHENG Guo-Qiang et al. Changes in MLS-BAEP in newborn piglets with hypoxic-ischemic brain damage during selective moderate head cooling therapy[J]. CJCP, 2013, 15(6): 484-489.
[1]Suppiej A, Rizzardi E, Zanardo V, Franzoi M, Ermani M, Orzan E. Reliability of hearing screening in high-risk neonates: comparative study of otoacoustic emission, automated and conventional auditory brainstem response[J]. Clin Neurophysiol, 2007, 118(4): 869-876.
[2]Yin R, Wilkinson AR, Chen C, Brosi DM, Jiang ZD. No close correlation between brainstem auditory function and peripheral auditory threshold in preterm infants at term age[J]. Clin Neurophysiol, 2008, 119(4): 791-795.
[3]Jiang ZD, Brosi DM, Shao XM, Wilkinson AR. Sustained depression of brainstem auditory electrophysiology during the first month in term infants after perinatal asphyxia[J]. Clin Neurophysiol, 2008, 119(7): 1496-1505.
[6]LeBlanc MH, Qian XB, Cai ZW. The effect of glucose during ischemia on brain ATP, lactate and glutamate in piglets[J]. Biol Neonate, 1997, 72(1): 243-254.
[7]Jiang ZD, Shao XM, Wilkinson AR. Changes in BAER amplitudes after perinatal asphyxia during the neonatal period in term infants[J]. Brain Dev, 2006, 28(9): 554-559.
[8]Jiang ZD, Xu X, Brosi DM, Shao XM, Wilkinson AR. Sub-optimal function of the auditory brainstem in term neonates with transient low Apgar scores[J]. Clin Neurophysiol, 2007, 118(5): 1088-1096.
[9]Jiang ZD, Brosi DM, Wang J, Xu X, Chen GQ, Shao XM, et al.Time course of brainstem pathophysiology during first month in term infants after perinatal asphyxia, revealed by MLS BAER latencies and intervals[J].Pediatr Res, 2003, 54(5): 680-687.
[10]Vannucci RC, Towfighi J, Vannucci SJ. Secondary energy failure after cerebral hypoxia-ischemia in the immature rat[J]. J Cereb Blood Flow Metab, 2004, 24(10): 1090-1097.
[11]Kusaka T, Ueno M, Miki T, Kuboi T, Nakamura S, Koyano K,et al. Relationship between cerebral oxygenation and phosphorylation potential during secondary energy failure in hypoxicischemic newborn piglets[J], Pediatr Res, 2009, 65(3): 317-322.
[12]Cheng QG, Sun JQ, Wang LS, Shao XM, Zhou WH. Effects of selective head cooling on cerebral blood flow and metabolism in newborn piglets after hypoxia-ischemia[J]. Early Hum Dev, 2011, 87 (2) 109-114.