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.

The Neu-Prem Trial: Neuromonitoring of Brains of Infants Born Preterm During Resuscitation-A Prospective Observational Cohort Study.

OBJECTIVE: To determine whether monitoring cerebral oxygen tissue saturation (StO2) with near-infrared spectroscopy (NIRS) and brain activity with amplitude-integrated electroencephalography (aEEG) can predict infants at risk for intraventricular hemorrhage (IVH) and death in the first 72 hours of life. STUDY DESIGN: A NIRS sensor and electroencephalography leads were placed on 127 newborns <32 weeks of gestational age at birth. Ten minutes of continuous NIRS and aEEG along with heart rate, peripheral arterial oxygen saturation, fraction of inspired oxygen, and mean airway pressure measurements were obtained in the delivery room. Once the infant was transferred to the neonatal intensive care unit, NIRS, aEEG, and vital signs were recorded until 72 hours of life. An ultrasound scan of the head was performed within the first 12 hours of life and again at 72 hours of life. RESULTS: Thirteen of the infants developed any IVH or died; of these, 4 developed severe IVH (grade 3-4) within 72 hours. There were no differences in either cerebral StO2 or aEEG in the infants with low-grade IVH. Infants who developed severe IVH or death had significantly lower cerebral StO2 from 8 to 10 minutes of life. CONCLUSIONS: aEEG was not predictive of IVH or death in the delivery room or in the neonatal intensive care unit. It may be possible to use NIRS in the delivery room to predict severe IVH and early death. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02605733.

Delayed Cord Clamping in Newborns Born at Term at Risk for Resuscitation: A Feasibility Randomized Clinical Trial.

Infants may benefit if resuscitation could be provided with an intact umbilical cord. Infants identified at risk for resuscitation were randomized to 1- or 5-minute cord clamping. The 5-minute group had greater cerebral oxygenation and blood pressure. Studies are needed to determine whether this translates into improved outcomes. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02827409.