Use of Venous Pco 2 in Determination of Death by Neurological Criteria in Children.

BACKGROUND: Compare the increase in partial pressure of carbon dioxide (Pco2 ) from venous blood samples with that of arterial blood samples during apnea challenge test in determination of death by neurological criteria.

METHODS: Prospective nonrandomized cohort study in tertiary care pediatric intensive care unit. Patients older than 37 week's gestation admitted to PICU with irreversible brain injury at the time when attending physician will perform apnea challenge test as part of brain death examination from October 2015 till September 2017.

INTERVENTIONS: None.

RESULTS: The primary outcome was to measure and compare the increase in Pco2 from venous blood samples with that from arterial blood samples during apnea challenge test. A total of nine apnea challenge tests from seven patients (ages five months to 17 years) were included in the study. Pco2 in venous blood sample increased less than that in arterial blood samples (venous, 26.1 mm Hg; S.D., 10.1; 95% confidence interval, 18 to 34 mm Hg; arterial, 33.9 mm Hg; S.D., 12.0; 95% confidence interval, 24 to 43 mm Hg) (P = 0.02).

CONCLUSION: Postapnea challenge test Pco2 of 60 mm Hg along with increase of 20 mm Hg in venous blood sample correlated to Pco2 greater than 60 mm Hg along with increase of greater than 20 mm Hg in arterial blood sample. Further studies are warranted to assess if current recommendations for determination of death by neurological criteria in children can be modified to allow for use of venous blood samples as an alternate to arterial blood samples.