Cordero Leandro, Timan Christopher J, Waters Heather H, Sachs Larry A
Pediatrics Department, The Ohio State University Medical Center, Columbus, OH 43210-1228, USA.
J Perinatol. 2002 Jul-Aug;22(5):348-53. doi: 10.1038/sj.jp.7210736.
To determine mean arterial pressure values during the first 24 hours for "stable" and "unstable" extremely low birth weight (ELBW) infants and to ascertain its association with perinatal factors.
In ELBW infants, hypotension is diagnosed by nonspecific clinical signs together with reference arterial pressure values extrapolated from regression models or from scarce actual observations.
Retrospective cohort study.
101 ELBW (< or = 600 g) infants born in our medical center (1989-2000). Considered stable were 36 infants with umbilical cord hemoglobin > or = 14 g/dl who, although mechanically ventilated, had normal acid-base balance, no patent ductus arteriosus, had not received indomethacin, steroids, muscle relaxants, narcotics, were never treated for hypotension and survived at least 7 days. The remaining 65 infants constituted the unstable group. Arterial pressures were determined by oscillometry (OBP) and direct transducer readings through an umbilical line (MAP). All admission and 10% of the readings were by OBP; the remaining 1877 measurements were by MAP.
Stable and unstable infants were similar in birth weight, demographics, history of chorioamnionitis, antepartum steroids, low Apgar scores, administration of epinephrine during resuscitation, and sepsis. Stable infants were different from unstable in gestational age (27+/-2 vs 25+/-2 weeks' gestational age [w GA]), history of preterm labor, preeclampsia, and neonatal mortality (22 vs 68%). Admission OBP (30+/-7 vs 29+/-10 Torr) were similar and 1-hour MAP were different (30+/-6 vs 27+/-7 Torr) between both groups. MAP for stable infants was higher throughout the 24 hours. Greater differences were noted between 3 and 6 hours when 34 of 65 unstable infants were treated for hypotension. Mean MAP and 10 percentile values for stable infants at 1, 3, 6, 12, and 24 hours were 30 (22), 31 (24), 32 (25), 34 (24), and 35 (28) Torr, respectively. MAPs did not correlate with birth weight, but they were lower among 19 stable infants < or = 26 w GA than among 17 stable infants > or = 27 w GA. History of preeclampsia, antenatal steroids, intratracheal epinephrine and cord hemoglobin did not influence MAP. Low 1-minute Apgar score and intracranial hemorrhage were associated with low MAP during the first day.
There is a wide variation of GA among ELBW infants. MAPs increase with GA and with postnatal age. Shortly after birth, arterial pressures are similar for stable and unstable infants. Failure to increase MAP between 3 and 6 hours of life should create concern. MAP < or = 28 Torr at 3 hours of life is a reasonable, but not absolute, predictor of the need for hypotension treatment.
确定“稳定型”和“不稳定型”极低出生体重（ELBW）婴儿出生后最初24小时内的平均动脉压值，并确定其与围产期因素的关联。
在ELBW婴儿中，低血压是通过非特异性临床体征以及从回归模型或稀少的实际观察中推断出的参考动脉压值来诊断的。
回顾性队列研究。
101例在我们医疗中心出生（1989 - 2000年）的ELBW（≤600克）婴儿。36例脐带血红蛋白≥14克/分升的婴儿被视为稳定型，尽管接受机械通气，但酸碱平衡正常，无动脉导管未闭，未接受吲哚美辛、类固醇、肌肉松弛剂、麻醉剂治疗，从未接受过低血压治疗且存活至少7天。其余65例婴儿构成不稳定组。通过示波法（OBP）和经脐动脉导管直接换能器读数（MAP）测定动脉压。所有入院时及10%的读数采用OBP测量；其余1877次测量采用MAP。
稳定型和不稳定型婴儿在出生体重、人口统计学特征、绒毛膜羊膜炎病史、产前使用类固醇、低Apgar评分、复苏时使用肾上腺素以及败血症方面相似。稳定型婴儿与不稳定型婴儿在胎龄（27±2周与25±2周胎龄[w GA]）、早产史、先兆子痫和新生儿死亡率（22%与68%）方面存在差异。两组入院时的OBP（30±7与29±10 Torr）相似，但1小时时的MAP不同（30±6与27±7 Torr）。稳定型婴儿在24小时内的MAP始终较高。在3至6小时之间差异更大，此时65例不稳定型婴儿中有34例接受了低血压治疗。稳定型婴儿在1、3、6、12和24小时时的平均MAP及第10百分位数分别为30（22）、31（24）、32（25）、34（24）和35（28）Torr。MAP与出生体重无关，但在≤26周胎龄的19例稳定型婴儿中低于≥27周胎龄的17例稳定型婴儿。先兆子痫病史、产前类固醇、气管内使用肾上腺素和脐带血红蛋白不影响MAP。出生后第1天，1分钟Apgar评分低和颅内出血与低MAP相关。
ELBW婴儿的胎龄差异很大。MAP随胎龄和出生后年龄增加。出生后不久，稳定型和不稳定型婴儿的动脉压相似。出生后3至6小时内MAP未能升高应引起关注。出生后3小时MAP≤28 Torr是低血压治疗需求的合理但非绝对的预测指标。
