Division of Neonatology, Department of Pediatrics, Hospital for Sick Children, Toronto, Ontario, Canada.
Department of Pediatrics, Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
J Pediatr. 2021 Sep;236:40-46.e3. doi: 10.1016/j.jpeds.2021.05.026. Epub 2021 May 18.
To investigate the circulatory physiology of hypotension during the first day after birth among stable extremely preterm neonates.
Case-control study of neonates born at ≤27 weeks gestational age with hypotension, defined as mean blood pressure in mmHg less than gestational age in weeks for at least 1 hour during the first 24 hours after birth, who underwent comprehensive echocardiography assessment before commencement of cardiovascular drugs. Neonates with hypotension (n = 14) were matched by gestational age and intensity of respiratory support with normotensive neonates (n = 27) who underwent serial echocardiography during the first day after birth, and relatively contemporaneous echocardiography assessments were used for comparison.
Neonates with hypotension had a higher frequency of patent ductus arteriosus ≥1.5 mm (71% vs 15%; P < .001) and ductal size (median diameter, 1.6 mm [IQR, 1.4-2.1] vs 1.0 mm [IQR, 0-1.3]; P = .002), higher echocardiography indices of left ventricular systolic function (mean shortening fraction, 34 ± 7% vs 26 ± 4%; P < .001; mean longitudinal strain, -16 ± 5% vs -14 ± 3%; P = .04; and mean velocity of circumferential fiber shortening, 1.24 ± 0.35 circ/s vs 1.01 ± 0.28 circ/s; P = .03), lower estimates of left ventricular afterload (mean end-systolic wall stress, 20 ± 7 g/cm vs 30 ± 9 g/cm; P < .001 and mean arterial elastance, 43 ± 19 mmHg/mL vs 60 ± 22 mmHg/mL; P = .01), without significant difference in stress-velocity index z-score (-0.42 ± 1.60 vs -0.88 ± 1.30; P = .33). Neonates with hypotension had higher rates of any degree of intraventricular hemorrhage (71% vs 22%; P = .006).
Low blood pressure in otherwise well extremely low gestational age neonates was associated with low systemic afterload and larger patent ductus arteriosus, but not left ventricular dysfunction.
研究稳定的极早产儿出生后第 1 天低血压的循环生理学。
对胎龄≤27 周且出生后 24 小时内至少有 1 小时血压持续低于胎龄周数的低血压新生儿进行病例对照研究，定义为平均血压低于胎龄周数，接受全面超声心动图评估在开始心血管药物治疗之前。通过胎龄和呼吸支持强度与出生后第 1 天接受连续超声心动图检查的血压正常新生儿（n=27）相匹配，使用相对同时的超声心动图评估进行比较。
低血压新生儿更频繁地存在直径≥1.5mm 的未闭动脉导管（71%比 15%；P<0.001）和更大的导管直径（中位数直径，1.6mm[IQR，1.4-2.1]比 1.0mm[IQR，0-1.3]；P=0.002），左心室收缩功能的超声心动图指数更高（平均缩短分数，34±7%比 26±4%；P<0.001；平均纵向应变，-16±5%比-14±3%；P=0.04；和平均周向纤维缩短速度，1.24±0.35circ/s 比 1.01±0.28circ/s；P=0.03），左心室后负荷的估计值更低（平均收缩末期壁应力，20±7g/cm 比 30±9g/cm；P<0.001和平均动脉弹性，43±19mmHg/mL 比 60±22mmHg/mL；P=0.01），但速度-压力指数 z 评分无显著差异（-0.42±1.60 比 -0.88±1.30；P=0.33）。低血压新生儿任何程度的颅内出血发生率更高（71%比 22%；P=0.006）。
在其他方面情况良好的极低胎龄早产儿中，血压低与较低的全身后负荷和较大的动脉导管未闭有关，但与左心室功能障碍无关。
