Hypocarbia and adverse outcome in neonatal hypoxic-ischemic encephalopathy.

Abstract

OBJECTIVE:

To evaluate the association between early hypocarbia and 18- to 22-month outcome among neonates with hypoxic-ischemic encephalopathy.

STUDY DESIGN:

Data from the National Institute of Child Health and Human Development Neonatal Research Network randomized, controlled trial of whole-body hypothermia for neonatal hypoxic-ischemic encephalopathy were used for this secondary observational study. Infants (n = 204) had multiple blood gases recorded from birth to 12 hours of study intervention (hypothermia versus intensive care alone). The relationship between hypocarbia and outcome (death/disability at 18 to 22 months) was evaluated by unadjusted and adjusted analyses examining minimum PCO(2) and cumulative exposure to PCO(2) <35 mm Hg. The relationship between cumulative PCO(2) <35 mm Hg (calculated as the difference between 35 mm Hg and the sampled PCO(2) multiplied by the duration of time spent <35 mm Hg) and outcome was evaluated by level of exposure (none-high) using a multiple logistic regression analysis with adjustments for pH, level of encephalopathy, treatment group (± hypothermia), and time to spontaneous respiration and ventilator days; results were expressed as odds ratios and 95% confidence intervals. Alternative models of CO(2) concentration were explored to account for fluctuations in CO(2).

RESULTS:

Both minimum PCO(2) and cumulative PCO(2) <35 mm Hg were associated with poor outcome (P < .05). Moreover, death/disability increased with greater cumulative exposure to PCO(2) <35 mm Hg.

CONCLUSIONS:

Hypocarbia is associated with poor outcome after hypoxic-ischemic encephalopathy.

• Authors: Athina Pappas, Seetha Shankaran, Abbot R Laptook, John C Langer, Rebecca Bara, Richard A Ehrenkranz, Ronald N Goldberg, Abhik Das, Rosemary D Higgins, Jon E Tyson, Michele C Walsh, Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network
• Journal: The Journal of pediatrics (J Pediatr) Vol. 158 Issue 5 Pg. 752-758.e1 (May 2011) ISSN: 1097-6833 [Electronic] United States
• PMID: 21146184 (Publication Type: Comparative Study, Journal Article, Randomized Controlled Trial, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2011 Mosby, Inc. All rights reserved.

Chemical References

• Carbon Dioxide

Topics

• Carbon Dioxide (blood)
• Female
• Humans
• Hypocapnia (etiology, mortality, therapy)
• Hypothermia, Induced (methods)
• Hypoxia-Ischemia, Brain (complications, mortality, therapy)
• Infant, Newborn
• Male
• Survival Rate
• Treatment Outcome
• United States (epidemiology)