Battin Malcolm R, Penrice Juliet, Gunn Tania R, Gunn Alistair J
Newborn Service, National Women's Hospital, Auckland, New Zealand.
Pediatrics. 2003 Feb;111(2):244-51. doi: 10.1542/peds.111.2.244.
To assess the safety of selective head cooling in birth-asphyxiated term newborn infants while maintaining the rectal temperature at 35.0 degrees C or 34.5 degrees C.
Twenty-six term infants with Apgar <or=6 at 5 minutes or cord/first arterial pH <7.1, plus evidence of encephalopathy, were studied. After parental consent had been obtained, 13 infants received selective head cooling with the rectal temperature maintained at 35.0 degrees C in 6 infants and at 34.5 degrees C in 7 infants. The remaining 13 infants were normothermic. Cooling was achieved by circulating water at 10 degrees C through a cap placed around the head. Rectal, fontanelle, and nasopharyngeal temperatures were monitored.
One cooled infant died 2 days after rewarming, and 3 control infants died. Seizures occurred in 9 (69%)of 13 cooled infants and 5 (38%) of 13 control infants. Respiratory support within the first 72 hours of life was required in 10 of 13 infants in both the cooled and control groups. Three cooled infants and 1 control infant received nitric oxide for persistent pulmonary hypertension. During the same interval, 6 of the cooled infants and 4 of the control infants had episodes in which their blood pressure fell to <40 mm Hg; in 2 infants in each group, the lowest blood pressure was below 35 mm Hg. No requirement for volume expansion or increased inotropic support was seen in any infant during stepwise rewarming. All of the cooled infants demonstrated a fall in heart rate during cooling, but the rate was <80/min in only 2 cases and no infant had a rate <70/min. No infant demonstrated an abnormal rhythm or was clinically compromised by the change in heart rate. One infant cooled to a rectal temperature of 34.5 degrees C had a prolonged QT interval of 570 ms associated with a heart rate of 85/min on electrocardiogram aged 34 hours. This returned to normal after rewarming. Platelet counts below 150 x 10(9)/L, hypoglycemia below 2.6 mmol/L, and highest creatinine were not statistically different between cooled and control infants. Positive precooling blood cultures were found in 1 cooled and 1 control infant. The mean cap water input temperature used during cooling was 10 +/- 1 degrees C. During active cooling, the mean difference between rectal and nasopharyngeal temperature was 1.4 degrees C in the infants who were not receiving respiratory support, but this gradient could not be measured in those who were receiving respiratory support that involved delivery of warmed gases to the nasopharynx.
This study suggests that selective head cooling combined with mild systemic hypothermia of 34.4 degrees C or 35.0 degrees C is a stable, well-tolerated method of reducing cerebral temperature in term newborn infants after perinatal asphyxia.
评估选择性头部降温对足月窒息新生儿的安全性，同时将直肠温度维持在35.0℃或34.5℃。
研究了26例足月婴儿，这些婴儿5分钟时阿氏评分≤6或脐血/首次动脉血pH＜7.1，并有脑病证据。获得家长同意后，13例婴儿接受选择性头部降温，其中6例婴儿直肠温度维持在35.0℃，7例婴儿直肠温度维持在34.5℃。其余13例婴儿体温正常。通过让10℃的水在环绕头部的帽状物中循环来实现降温。监测直肠、囟门和鼻咽温度。
1例降温婴儿复温2天后死亡，3例对照婴儿死亡。13例降温婴儿中有9例（69%）发生惊厥，13例对照婴儿中有5例（38%）发生惊厥。降温组和对照组的13例婴儿中均有10例在出生后72小时内需进行呼吸支持。3例降温婴儿和1例对照婴儿因持续性肺动脉高压接受一氧化氮治疗。在同一时间段内，6例降温婴儿和4例对照婴儿出现血压降至＜40 mmHg的情况；每组各有2例婴儿，最低血压低于35 mmHg。在逐步复温过程中，未发现任何婴儿需要扩容或增加正性肌力支持。所有降温婴儿在降温过程中均出现心率下降，但仅2例心率＜80次/分钟，无婴儿心率＜70次/分钟。没有婴儿出现心律失常，也没有婴儿因心率变化而出现临床问题。1例直肠温度降至34.5℃的婴儿在34小时龄时心电图显示QT间期延长至570毫秒，心率85次/分钟。复温后恢复正常。降温婴儿和对照婴儿的血小板计数低于150×10⁹/L、血糖低于2.6 mmol/L以及最高肌酐水平在统计学上无差异。1例降温婴儿和1例对照婴儿血培养在降温前呈阳性。降温期间使用的帽状物进水平均温度为10±1℃。在主动降温期间，未接受呼吸支持的婴儿直肠温度与鼻咽温度的平均差值为1.4℃，但在接受涉及向鼻咽部输送温热气体的呼吸支持的婴儿中无法测量该梯度。
本研究表明，选择性头部降温联合34.4℃或35.0℃的轻度全身低温是一种稳定、耐受性良好的降低足月新生儿围产期窒息后脑温的方法。
