Dassios Theodore, Ali Kamal, Rossor Thomas, Greenough Anne
Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, 4th Floor Golden Jubilee Wing, Denmark Hill, SE5 9RS, London, UK.
Division of Asthma, Allergy and Lung Biology, MRC-Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, UK.
J Clin Monit Comput. 2017 Dec;31(6):1229-1234. doi: 10.1007/s10877-016-9969-7. Epub 2016 Dec 23.
Oxygenation impairment can be assessed non-invasively by determining the degree of right-to-left shunt and ventilation/perfusion (V/Q) inequality. These indices have been used in sick newborn infants, but normative values have not been reported which are essential to determine the magnitude of the abnormality. We, therefore, aimed to measure the shunt and V/Q in infants with no history of respiratory conditions and determine if there was any effect of supine or prone position and the reproducibility of the data. Data were analysed from infants who had undergone a hypoxic challenge and in a subset who had been assessed in the supine or prone position. Transcutaneous oxygen saturations (SpO) were recorded at fractions of inspired oxygen (FO) of 0.21 and 0.15. Two independent raters used a computer software algorithm which analysed and fitted paired data for FO and SpO and derived a curve which represented the best fit for each infant's data and calculated the shunt and V/Q. The raters ability to interpret the SpO value which corresponded to a given FO was compared. The downwards displacement of the FO versus SpO curve was used to estimate the degree of right-to-left shunt and the rightwards shift of the curve was used to calculate the V/Q ratio. The mean (SD) gestational age of the 145 infants was 39 (1.6) weeks, their birth weight was 2990 (578) gms and median (range) postnatal age at measurement 3 (1-8) days. The mean (SD) V/Q ratio was 0.95 (0.21). None of the infants had a right-to-left shunt. No significant differences were found in V/Q in the supine compared to the prone position. The intraclass correlation coefficient of V/Q between two independent raters was 0.968 (95% CI 0.947-0.980), p < 0.001. Right-to-left shunt and V/Q ratio in healthy newborn infants were similar in the prone compared to the supine position.
可通过确定右向左分流程度和通气/灌注（V/Q）不均等来无创评估氧合障碍。这些指标已用于患病新生儿，但尚未报告规范值，而规范值对于确定异常程度至关重要。因此，我们旨在测量无呼吸疾病史婴儿的分流和V/Q，并确定仰卧位或俯卧位是否有任何影响以及数据的可重复性。对接受低氧挑战的婴儿以及在仰卧位或俯卧位进行评估的亚组婴儿的数据进行了分析。在吸入氧分数（FiO）为0.21和0.15时记录经皮血氧饱和度（SpO）。两名独立评估者使用计算机软件算法，该算法分析并拟合FiO和SpO的配对数据，得出代表每个婴儿数据最佳拟合的曲线，并计算分流和V/Q。比较了评估者解释与给定FiO相对应的SpO值的能力。FiO与SpO曲线的向下位移用于估计右向左分流程度，曲线的向右位移用于计算V/Q比值。145名婴儿的平均（标准差）胎龄为39（1.6）周，出生体重为2990（578）克，测量时的中位（范围）产后年龄为3（1 - 8）天。平均（标准差）V/Q比值为0.95（0.21）。所有婴儿均无右向左分流。仰卧位和俯卧位的V/Q无显著差异。两名独立评估者之间V/Q的组内相关系数为0.968（95%可信区间0.947 - 0.980），p < 0.001。与仰卧位相比，健康新生儿俯卧位的右向左分流和V/Q比值相似。
