Incidence of Hypocapnia, Hypercapnia, and Acidosis and the Associated Risk of Adverse Events in Preterm Neonates.

BACKGROUND: Permissive hypercapnia is a lung-protection strategy. We sought to review our current clinical practice for the range of permissive hypercapnia and identify the relationship between PaCO2 and pH and adverse outcomes. METHODS: A secondary analysis of a delayed cord-clamping clinical trial was performed on all arterial blood gas tests in the first 72 h in infants < 32 weeks gestational age. All arterial blood gas values were categorized into a clinical range to determine the percent likelihood of occurring in the total sample. The univariate and multivariate relationships of severe adverse events and the time-weighted PaCO2 , fluctuation of PaCO2 , maximal and minimal PaCO2 , base excess, and pH were assessed. RESULTS: 147 infants with birthweight of 1,206 ± 395 g and gestational age of 28 ± 2 weeks were included. Of the 1,316 total samples, < 2% had hypocapnia (PaCO2 <30 mm Hg), 47% were normocapnic (PaCO2 35-45 mm Hg), 26.5% had mild hypercapnia (PaCO2 45-55 mm Hg), 13% had moderate hypercapnia (PaCO2 55-65 mm Hg), and 6.5% had severe hypercapnia (PaCO2 ≥ 65 mm Hg). There were no adverse events associated with hypocapnia. Subjects with death/severe intraventricular hemorrhage had a higher mean PaCO2 of 52.3 versus 44.7 (odds ratio [OR] 1.16, 95% CI 1.04-1.29, P = .006), higher variability of PaCO2 with a standard deviation of 12.6 versus 7.8 (OR 1.15, 95% CI 1.03-1.27, P = .01), and a lower minimum pH of 7.03 versus 7.23 (OR 0, 95% CI 0-0.06, P = .003). There was no significant difference in any variables in subjects who developed other adverse events. CONCLUSION: The routine targeting of higher than normal PaCO2 goals may lead to a low incidence of hypocapnia and associated adverse events. Hypercapnia is common, and moderate hypercapnia may increase the risk of neurologic injury and provide little pulmonary benefit.

AmniSure placental alpha microglobulin-1 rapid immunoassay versus standard diagnostic methods for detection of rupture of membranes.

The purpose of this study was to compare the AmniSure rapid immunoassay with standard methods for diagnosing rupture of fetal membranes. Patients presenting with signs/symptoms of membrane rupture between 15 and 42 weeks of gestation were invited to participate. Standard/control methods were performed to establish a diagnosis and compare it with AmniSure results. AmniSure performance metrics and their 95% confidence intervals were calculated. A total of 203 patients agreed to participate. Discrepancies between the control method and AmniSure were noted in seven cases. In these cases, true positives and negatives were determined by retesting with the control method and AmniSure and by noting sonographic evidence of low amniotic fluid. In the final analysis, the AmniSure diagnostic test demonstrated a sensitivity of 98.9%, specificity of 100%, positive predictive value of 100%, and a negative predictive value of 99.1%. AmniSure is highly accurate in diagnosing fetal membrane rupture.