Biomedical subjects
Publications and source records attributed to L N Archer.
A tape recording system for recording night cough in asthmatics at home is described. Objective cough counts and half hour periods containing cough did not correlate with diary card scores awarded to eight children on seven nights each. Night cough diary scores may mislead in the assessment of symptom severity.
A boy with congenital hypothyroidism and hereditary raised thyroxine binding globulin is described. This hitherto unreported combination resulted in under treatment of the thyroid deficiency until serum thyroid stimulating hormone measurement became routinely available. Inadequate L-thyroxine replacement treatment between 2 and 7 years of age caused retarded bone maturation, poor growth velocity, and probably added to his educational difficulties.
Among 425 pre-term low birthweight babies who survived more than 48 hours there were 130 with idiopathic respiratory distress syndrome, 73 of whom received ventilation for their disease. The ductus arteriosus was considered patent by clinical criteria in 41 of these babies, all but 1 of whom had a murmur. Of the remaining 32 infants there were 2 babies only who died and both were found to have a patent ductus arteriosus which had not been detected clinically. Another baby died whilst being ventilated for idiopathic respiratory distress syndrome and although autopsy information is not available it seems likely that factors other than a patent ductus arteriosus caused death. The mean age of murmur detection in those ventilated infants considered to have a patent ductus arteriosus was 6 days (range 2-19). Infants without a murmur or other features of a ductus arteriosus did not require to be ventilated beyond day 7 with the exception of the 2 fatalities already mentioned. Thus, relying on clinical criteria and particularly on the presence of a murmur, if sought often, rarely results in missing or seriously delaying the diagnosis of patent ductus arteriosus in babies with severe idiopathic respiratory distress syndrome.
Sixteen children aged under 5 years with chronic asthma completed a double-blind crossover trial of treatment with oral choline theophyllinate (6.7 mg/kg four times daily) and nebulised sodium cromoglycate (20 mg four times daily). The trial comprised three 8-week treatment periods during which active sodium cromoglycate, active choline theophyllinate, and placebo were given in random order. Symptom scores for sleep disturbance, cough, wheeze, and daily activities were similar during the three treatment periods if results were analysed using Friedman's non-parametric analysis of variance. However the Mantel-Haenszel test showed that sodium cromoglycate was superior to placebo (P less than 0.05) in maintaining normal daily activities. Either regimen is safe and well tolerated by young children.
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Inhaled nitric oxide is a specific pulmonary vasodilator. This study was undertaken to assess the effect on pulmonary arterial pressure of administering 100% oxygen compared with nitric oxide in oxygen. Thirteen mechanically ventilated children undergoing routine cardiac catheterization for the investigation of congenital heart disease were studied. Pulmonary arterial pressures were measured during inhalation of 30% oxygen (baseline), 100% oxygen, and nitric oxide (40 parts per million) in oxygen. In addition, in six children the pulmonary/systemic blood flow ratio and pulmonary vascular resistance were calculated using oxygen content, an assumed value for oxygen uptake, and the Fick principle. Results were compared using analysis of variance and the Wilcoxon signed-rank test. Pulmonary arterial pressure decreased from a mean value of 29.5 mmHg (SD 15.1) to 25.6 mmHg (SD 9.3), p = 0.048, after increasing the inspired oxygen fraction from 0.3 to 1.0. The addition of nitric oxide caused a further reduction to 22.9 mmHg (SD 7.9), p = 0.0001. There was no change in systemic arterial pressure or heart rate during the study period, but a small increase occurred in the mean methemoglobin level (1.1% to 1.3%) p = 0.039. Changes in the pulmonary/systemic blood flow ratio and pulmonary vascular resistance (n = 6) were not significant. Nitric oxide in oxygen appears to be a more potent pulmonary vasodilator than oxygen alone in pediatric patients with congenital cardiac defects.
Doppler ultrasound recordings were made from the anterior cerebral arteries of 40 normal full-term babies and 14 mature babies with intracranial pathology. The maximum velocity waveforms were extracted using spectral analysis and further analyzed using the Pourcelot resistance index method and the principal component method. Principal component analysis was found to be superior to the currently widely used resistance index method and may significantly enhance the value of Doppler ultrasound for detecting abnormal cerebral haemodynamics in neonates.