No abstract

We conclude that the incidence of PND is much higher than currently recognised, and has a very significant effect on post-operative morbidity and mortality. Most children who survive the post-operative period will recover nerve function within 3 months.

There is evidence that early diagnosis of postoperative phrenic nerve damage may improve outcome, by allowing early surgical treatment, in children following cardiac surgery. This has prompted the development of a simple method for measuring phrenic nerve latency at the bedside in children. We have evaluated the reproducibility of measurements made with this system in 11 children (4 months to 13 yrs) admitted for routine surgery or cardiac catheterizations, and have assessed the various components of variability inherent in the measurement of phrenic nerve latency. The overall variability of the phrenic nerve latency with this technique (95% confidence interval) is approximately +/- 1 ms, and differences greater than this between measurements are likely to reflect a real change in phrenic nerve function. Our results indicate that the bedside technique should be a useful method of the objective assessment of phrenic nerve function in children recovering from cardiac surgery.

Adenosine concentrations were measured in umbilical venous blood obtained by cordocentesis from 14 fetuses of 19-34 weeks' gestation. The concentration did not change significantly with gestational age, but anaemic fetuses showed significantly increased concentrations of adenosine and there was a positive association with blood oxygen tension. These findings suggest that the fetus responds to tissue hypoxia by increasing blood adenosine concentrations from at least 19 weeks' gestation. (Arch Dis Child 1993;68:35-6) Postnatal studies of infants who had been subjected to perinatal asphyxia have reported increased concentrations of catecholamines,' adenosine, and hypoxanthine in blood samples.2 5 Cordocentesis, ultrasound guided umbilical venous blood sampling, has now made it possible to investigate the metabolic consequences of intrauterine hypoxia. Previous work, using cordocentesis samples from rhesus isoimmunised fetuses, showed the presence of hypoxaemia and anaemia, and showed that these abnormalities were associated with increased concentrations of catecholamines.6The aim of this study was to measure adenosine concentrations in fetuses and determine their relation with prenatal hypoxia.