Cerebral blood flow and carbon dioxide reactivity in neonates during venoarterial extracorporeal life support
Stockwell, J.A.; Goldstein, R.F.; Ungerleider, R.M.; Kern, F.H.; Meliones, J.N.; Greeley, W.J.
Critical Care Medicine 24(1): 155-162
1996
ISSN/ISBN: 0090-3493 PMID: 8565521 Document Number: 469380
Objectives: a) To determine if cerebral blood flow is symmetric after internal carotid artery and ipsilateral internal jugular vein ligation in infants during venoarterial extracorporeal life support. b) To determine the cerebral CO-2 reactivity (DELTA cerebral blood flow/ A torr CO-2) of neonates during venoarterial extracorporeal life support and its correlation to neurodevelopmental outcome. Design: Prospective, clinical study. Setting: University hospital pediatric intensive care unit. Patients: Fourteen neonates with respiratory failure who were receiving venoarterial extracorporeal life support. Interventions: Paco-2 was altered by adjusting the CO-2 gas flow through the membrane oxygenator. Cerebral blood flow was measured over both parietal-temporal regions at three Paco-2 values using xenon-133 clearance methodology. Cerebral blood flow measurements were made early ( ltoreq 12 hrs of extracorporeal life support, n = 10) or late ( gt 48 hrs of extracorporeal life support, n = 10). In six of 14 infants, both early and late cerebral blood flow rates were measured. Pao-2, mean arterial pressure, pump flow rate, and temperature were stable during each study period. Neurodevelopmental outcome was assessed in the neonatal follow-up clinic. Measurements and Main Results: Right and left hemispheric cerebral blood flow rates were significantly correlated with each other during early and late extracorporeal life support (p = .0001; r-2 = .91). Overall, hemispheric cerebral blood flow was statistically symmetric. There was no association of CO-2 reactivity (A cerebral blood flow/A torr Pco-2, range 0.04 to 1.36 mL/min/100 g/torr) with short-term neurodevelopmental outcome. Infants with normal neurodevelopmental outcome had variable CO-2 reactivity (range 0.04 to 0.67 mL/min/100 g/torr). Normal short-term neurodevelopmental outcome was observed in two infants with cerebral blood flow of lt 10 mL/min/100 g. Conclusions: Hemispheric cerebral blood flow was symmetric in infants during early and late venoarterial extracorporeal life support. Some subgroups showed a trend toward decreased right hemispheric cerebral blood flow, but the small number of patients limited interpretation of this finding. CO-2 reactivity and cerebral blood flow were highly variable in this population, and were not predictive of short-term neurodevelopmental outcome. Stressed neonates with extremely low cerebral blood flow rates may have relatively normal short-term neurodevelopmental outcome after venoarterial extracorporeal life support.