Comparison between creatine kinase brain isoenzyme (CKBB) activity and Sarnat score for prediction of adverse outcome following perinatal asphyxia.
OBJECTIVE
To assess whether plasma creatine kinase brain isoenzyme (CKBB) levels or Sarnat scores are more accurate for prediction of poor neurological outcome in babies with suspected birth asphyxia.


METHODS
In a retrospective study of 97 babies CKBB levels were compared to the presence of severe hypoxic ischaemic encephalopathy (HIE) as a predictive test for these outcomes: developmental delay, cerebral palsy, visual problems, deafness or death from perinatal asphyxia. The tests were compared using positive predictive values (PPV) and likelihood ratios (LR) with confidence intervals (CI).


RESULTS
3 babies had died from perinatal asphyxia and 14 survivors were found to have neurological or developmental problems. CKBB was elevated in babies with severe HIE (p = 0.0004). A receiver operator characteristic (ROC) curve showed the optimal discriminating value for CKBB to be 21 IU/L but the CKBB was a poor predictive test. For prediction of adverse outcome: CKBB > 21 sensitivity 76%, specificity 40%, PPV 21% and LR 1.3 (95% CI 0.8-1.7). Severe HIE sensitivity 53%, specificity 95%, PPV 69% and LR 10.6 (95% CI 3.8-29.2).


CONCLUSIONS
CKBB is elevated following birth asphyxia but is a poor predictor of adverse neurological outcome.
Sweet
D G
DG
Royal Maternity Hospital Neonatal Unit, Queen's University of Belfast, Northern Ireland. dsweet@dnet.co.uk
Bell
A H
AH
McClure
G
G
Wallace
I J
IJ
Shields
M D
MD
D001238:Asphyxia Neonatorum / Q000150:complications / Q000201:enzymology* / Q000401:mortality; D001921:Brain / Q000201:enzymology*; D003402:Creatine Kinase / Q000378:metabolism*; D005260:Female; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000201:enzymology / Q000209:etiology; D007231:Infant, Newborn; D007527:Isoenzymes; D008297:Male; D011247:Pregnancy; D011379:Prognosis; D012372:ROC Curve; D012680:Sensitivity and Specificity
D007527:Isoenzymes; D003402:Creatine Kinase