• Blood carbon dioxide levels and adverse outcome in neonatal hypoxic-ischemic encephalopathy.

      Nadeem, Montasser; Murray, Deirdre; Boylan, Geraldine; Dempsey, Eugene M; Ryan, C Anthony; Neonatal Intensive Care Unit, Cork University Maternity Hospital, Cork, Ireland. (2012-01-31)
      We investigated pCO(2) patterns and the relationship between pCO(2) levels and neurodevelopmental outcome in term infants with hypoxic-ischemic encephalopathy. Blood gases during the first 72 hours of life were collected from 52 infants with hypoxic-ischemic encephalopathy. Moderate hypocapnia (pCO(2) <3.3 kPa), severe hypocapnia (pCO(2) <2.6 kPa), and hypercapnia (pCO(2) >6.6 kPa) were correlated to neurodevelopmental outcome at 24 months. Normocapnia was documented in 416/551 (75.5%) of samples and was present during the entire 72 hours in only 6 out of 52 infants. Mean (standard deviation) pCO(2) values did not differ between infants with normal and abnormal outcomes: 5.43 (2.4) and 5.41 (2.03), respectively. There was no significant association between moderate hypocapnia, severe hypocapnia, or hypercapnia and adverse outcome (odds ratio [OR] = 1.84, 95% confidence interval [CI] = 0.49 to 6.89; OR = 3.16, CI = 0.14 to 28.45; and OR = 1.07, CI = 0.24 to 5.45, respectively). In conclusion, only one in nine newborns had normocapnia throughout the first 72 hours. Severe hypocapnia was rare and occurred only in ventilated babies. Hypercapnia and hypocapnia in infants with hypoxic-ischemic encephalopathy during the first 72 hours of life were not associated with adverse outcome.
    • Fetal heart rate patterns in neonatal hypoxic-ischemic encephalopathy: relationship with early cerebral activity and neurodevelopmental outcome.

      Murray, Deirdre M; O'Riordan, Mairead N; Horgan, Richard; Boylan, Geraldine; Higgins, John R; Ryan, Cornelius A; Department of Paediatrics and Child Health, University College Cork, Cork, University Maternity Hospital, Cork, Wilton, Cork, Ireland. d.murray@ucc.ie (2012-01-31)
      Despite widespread use of fetal heart rate monitoring, the timing of injury in hypoxic-ischemic encephalopathy (HIE) remains unclear. Our aim was to examine fetal heart rate patterns during labor in infants with clinical and electroencephalographic (EEG) evidence of HIE and to relate these findings to neurodevelopmental outcome. Timing of onset of pathological cardiotocographs (CTGs) was determined in each case by two blinded reviewers and related to EEG grade at birth and neurological outcome at 24 months. CTGs were available in 35 infants with HIE (17 mild, 12 moderate, 6 severe on EEG). Admission CTGs were normal in 24/35 (69%), suspicious in 8/35 (23%), and pathological in 3/35 (8%). All CTGs developed nonreassuring features prior to delivery. Three patterns of fetal heart rate abnormalities were seen: group 1, abnormal CTGs on admission in 11/35 (31%); group 2, normal CTGs on admission with gradual deterioration to pathological in 20/35 cases (57%); and group 3, normal CTGs on admission with acute sentinel events in 4/35 (11.5%). The median (interquartile range) duration between the development of pathological CTGs and delivery was 145 (81, 221) minutes in group 2 and 22 (12, 28) minutes in group 3. There was no correlation between duration of pathological CTG trace and grade of encephalopathy (R = 0.09, P = 0.63) or neurological outcome (P = 0.75). However, the grade of encephalopathy was significantly worse in group 3 (P = 0.001), with a trend to worse outcomes. The majority of infants with HIE have normal CTG traces on admission but develop pathological CTG patterns within hours of delivery. More severe encephalopathy was associated with normal admission CTG and acute sentinel events shortly before delivery.