Krediet Tannette G, Valk Leonieke, Hempenius Ingrid, Egberts Johannes, van Bel Frank
Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center, Utrecht, The Netherlands.
Biol Neonate. 2002;82(3):150-4. doi: 10.1159/000063609.
A low blood pressure is common in preterm infants with respiratory distress syndrome (RDS). A diminished vascular resistance appears to be an important cause. The endogenous production of nitric oxide (NO), a mediator of vascular smooth muscle relaxation, has been shown to be higher in infants with RDS than in those without. Infants with persistent pulmonary hypertension showed decreased endogenous NO levels as compared with controls. Severe RDS in preterm infants may be accompanied by persistent pulmonary hypertension. To elucidate the role of NO in RDS and low blood pressure, we determined the endogenous NO production in infants with and without RDS by measuring urinary nitrite and nitrate excretions and plasma cGMP levels. In consecutively admitted preterm infants (gestational age <32 weeks), urine samples for measurement of NO(2) and NO(3) and plasma samples for the determination of the cGMP concentrations were serially collected during the 1st week of life. Arterial blood pressure, therapy to support blood pressure, and additional relevant clinical data were registered simultaneously. 27 infants with and 39 without RDS were included. The urinary NO(x) levels increased in all patients and were not different between both groups. The plasma cGMP concentrations were higher in the RDS group on days 2, 3, 4, and 7 (p < 0.05). The severity of RDS was positively correlated with plasma cGMP (r = 0.50, p = 0.0001). Although the arterial blood pressure did not differ between the groups, more blood pressure support was needed in the RDS infants during the first 4 days (p < 0.05). A positive correlation was found between blood pressure support and plasma cGMP (r = 0.34, p < 0.0001). The endogenous NO production was not different in infants with and without RDS. Increased plasma cGMP levels in the RDS infants were associated with the severity of RDS and the intensity of antihypotensive treatment. The origin of cGMP in infants with RDS requires further research.
低血压在患有呼吸窘迫综合征（RDS）的早产儿中很常见。血管阻力降低似乎是一个重要原因。一氧化氮（NO）是血管平滑肌舒张的介质，其内源生成在患有RDS的婴儿中已被证明高于未患RDS的婴儿。与对照组相比，患有持续性肺动脉高压的婴儿内源NO水平降低。早产儿的严重RDS可能伴有持续性肺动脉高压。为了阐明NO在RDS和低血压中的作用，我们通过测量尿中亚硝酸盐和硝酸盐排泄量以及血浆cGMP水平，测定了患有和未患RDS的婴儿的内源NO生成。在连续入院的早产儿（胎龄<32周）中，在出生后第1周内连续收集用于测量NO(2)和NO(3)的尿液样本以及用于测定cGMP浓度的血浆样本。同时记录动脉血压、支持血压的治疗方法以及其他相关临床数据。纳入了27例患有RDS的婴儿和39例未患RDS的婴儿。所有患者的尿NO(x)水平均升高，两组之间无差异。RDS组在第2、3、4和7天的血浆cGMP浓度较高（p<0.05）。RDS的严重程度与血浆cGMP呈正相关（r = 0.50，p = 0.0001）。尽管两组之间的动脉血压没有差异，但在最初4天内，RDS婴儿需要更多的血压支持（p<0.05）。发现血压支持与血浆cGMP之间存在正相关（r = 0.34，p<0.0001）。患有和未患RDS的婴儿的内源NO生成没有差异。RDS婴儿血浆cGMP水平升高与RDS的严重程度和抗低血压治疗的强度有关。RDS婴儿中cGMP的来源需要进一步研究。
