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Notes: Objectives To address the practical problems of routine umbilical cord blood sampling, to determine the ranges for pH, pCO2 and base deficit and to examine the relationships of these parameters between cord vessels.Design An observational study of umbilical cord artery and vein blood gas results.Setting A large district general hospital in the UK.Subject One thousand nine hundred and forty-two cord results from 2013 consecutive pregnancies of 34 weeks or more gestation, monitored by fetal scalp electrode during labour.Results Only 1448 (74.6%) of the 1942 supposedly paired samples had validated pH and pCO2data both from an artery and the vein; 54 (2.8%) had only one blood sample available, 90 (4.6%) had an error in the pH or pCO2 of one vessel and in 350 (18%) pairs the differences between vessels indicated that they were not sampled from artery and vein as intended. Only 60% of the cases with an arterial pH less than 7.05 had evidence of a metabolic acidosis (base deficit in the extracellular fluid 10 mmol/1 or more). Of all the cases, 2.5% had a venous-arterial pH difference greater than 0.22 units.Conclusions Both artery and vein cord samples must be taken and the results screened to ensure separate vessels have been sampled. Interpretation of the results requires the examination of pCO2 and base deficit of the extracellular fluid from each vessel as well as the pH. Confusion about the value of cord gas measurements may be due to the use of erroneous data and inadequate definitions of acidosis which do not differentiate between respiratory and metabolic components.

Notes: Objectives To investigate 1. whether an intelligent computer system could obtain a performance in labour management comparable with experts when using cardiotocograms (CTGs), patient information, and fetal blood sampling and 2. whether experts could be consistent and agree in their management of labour.Subjects An intelligent computer system and 17 clinicians experienced in fetal monitoring from 16 centres in the UK.Design Fifty cases with complete intrapartum CTGs and clinical data were reviewed by each expert and the system independently on two occasions, at least one month apart. Each CTG was scored in 15 min segments according to a protocol and estimates of the cervical dilatation and fetal scalp blood pH were given when requested.Main outcome measures Consistency and agreement in the recorded scores, agreement and timing of cases recommended for caesarean sections, fetal blood sampling rates, intervention in cases with poor outcome and intervention in cases with good clinical outcome.Results The system:〈list xml:id="l1" style="custom"〉1Agreed with experts well and significantly better than chance (67.33%, kappa = 0.31, P〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:14700328:BJO688:les" location="les.gif"/〉 0.001).2Was highly consistent (99.16%, kappa = 0.98, P 4.0001) when used by two operators independently.3Recommended no unnecessary intervention in cases with normal delivery and good condition (cord artery pH 〉 7.15, vein pH 〉 7.20, 5 min Apgar ≥ 9 and no resuscitation). This was better than all but two of the experts.4Recommended delivery by caesarean section in 11 cases; at least 15 of the 17 experts in each review also recommended caesarean section delivery in these cases. The majority did so within 15 min of the system and two-thirds did so within 30 min.5Identified as many of the birth asphyxiated cases (cord arterial pH 〈 7.05 and BDecf ≥ 12, and Apgar score at 5 min ≤ 7 with neonatal morbidity) as the majority of experts and one more than was acted upon clinically.The experts were found to be consistent and to agree. There was good agreement in the cases and the timing of caesarean section recommendations. The majority of experts did not recommend operative intervention in cases which had a normal delivery and good outcome, but did recommend operative interventions in 10 of 12 cases delivered with cord arterial pH c 7.05. However, in one of the cases delivered with birth asphyxia, 14 of the 17 experts and the system failed to recommend intervention.Conclusions The system's performance was found to be indistinguishable from the experts' in the 50 cases examined, but it was more consistent. This demonstrates the potential for an intelligent computer system to improve the interpretation of the CTG and decrease intervention. Furthermore, the good performance of most experts in this study demonstrates the potential effectiveness of the CTG and raises important questions regarding why the CTG has fallen short of expectations in current practice.