Direct measurement of the thermal responses of nude resting men in dry environments

Summary Two nude resting men were exposed for two-hour periods to each of 25 dry environments, with air temperatures ranging between 12.8° C and 49.1° C and wind speeds between 0.67 m/sec and 4.94 m/sec. The mean radiant temperature of the surroundings was kept equal to the air temperature. Rates of radiant and convective heat exchange were measured directly, separately and continuously. The men had reached a thermal steady state after 105 min in the warm environments, but not in the cold environments. Graphs are presented to show the effect of ambient temperature and wind speed on the radiation and convection rates attained after 105 min, as well as on metabolic rate, sweat evaporation rate, rectal temperature and mean skin temperature. These graphs revealed some important aspects of the behaviour of man's thermal control system. In particular the physiological conductance increased with increasing ambient temperature and then saturated at an ambient temperature near 35° C. This saturation resulted in a constant difference between rectal temperature and mean skin temperature irrespective of the environmental conditions.Published with the permission of the Chamber of Mines of South Africa.     

The place of 'active birth' in present-day obstetric practice

"Active birth' is becoming an increasingly prominent issue in obstetric practice. The psychosocial background of current public interest in the subject is examined. Guidelines are suggested to accommodate "active-birth' practices within the hospital environment. The Johannesburg Hospital experience of the application of these guidelines in the first 100 patients admitted to the "Midwives Active Birth Unit' is reported.     

Misoprostol for induction of labour: a systematic review.

OBJECTIVE: To determine, from the best available evidence, the effectiveness and safety of misoprostol administered vaginally or orally for third trimester cervical ripening or induction of labour. METHODS: Clinical trials of misoprostol used for cervical ripening or labour induction in the third trimester were identified from the register of randomised trials maintained by the Cochrane Pregnancy and Childbirth Group. All identified trials were considered for inclusion in the review according to a prespecified protocol. Primary outcomes were chosen to address clinical effectiveness (delivery within 24 hours) and safety (uterine hyperstimulation, caesarean section, serious maternal and neonatal morbidity) and were determined a priori. All meta-analyses were based on the intention-to-treat principle. In the absence of heterogeneity the summary statistics have been expressed as typical relative risk (RR) and 95% confidence interval (CI). RESULTS: Vaginal misoprostol: one small study showed that the use of misoprostol results in more effective cervical ripening and reduced need for oxytocin when compared with placebo. When compared with oxytocin, vaginal misoprostol was more effective for labour induction. The relative risk of failure to achieve vaginal delivery within 24 hours was 0.48 (95% CI 0.35 to 0.66). However, the relative risks for uterine hyperstimulation with and without fetal heart rate abnormalities were 2.54 (95% CI 1.12 to 5.77) and 2.96 (95% CI 2.11 to 4.14), respectively. In three out of four trials which studied women with intact membranes and unfavourable cervices, failure to achieve vaginal delivery within 24 hours was reduced with misoprostol when compared with other prostaglandins (RR 0.71, 95% CI 0.62 to 0.81). Vaginal misoprostol was associated with increased uterine hyperstimulation both without fetal heart rate changes (RR 1.67, 95% CI 1.30 to 2.14) and with associated fetal heart rate changes (RR 1.45, 95% CI 1.04 to 2.04). There was also an increase in meconium stained amniotic fluid following vaginal misoprostol (RR 1.38, 95% CI 1.06 to 1.79). Oral misoprostol: one small trial suggests that, when compared with placebo, oral misoprostol reduces the need for oxytocin and shortens the time between induction and delivery. Compared with other prostaglandins one small trial showed a reduced need for oxytocin with oral misoprostol. Two trials compared oral with vaginal misoprostol using different doses. No significant differences were evident. CONCLUSIONS: Overall, misoprostol appears to be more effective than conventional methods of cervical ripening and labour induction. Although no differences in perinatal outcome were shown, the studies were not sufficiently large to exclude the possibility of uncommon serious adverse effects. In particular the increase in uterine hyperstimulation with fetal heart rate changes following misoprostol is a matter for concern. It is possible that, if sufficient numbers are studied, an unacceptably high number of serious adverse events including uterine rupture and asphyxial fetal deaths may occur. The data at present are not robust enough to address the issue of safety. Thus, though misoprostol shows promise as a highly effective, inexpensive and convenient agent for labour induction, it cannot be recommended for routine use at this stage. Lower dose misoprostol regimens should be investigated further.     

Ambulatory blood pressure monitoring during pregnancy: validation of the TM-2420 monitor

To validate the accuracy of the TM-2420 ambulatory blood pressure monitor in pregnant women, its measurements were compared with those taken simultaneously by two trained observers using a random zero sphygmomanometer. Each of 30 pregnant women had her blood pressure measured three times. The mean differences between the monitor and the averaged observer measurements were -0.53 +/- 2.7 mmHg for systolic blood pressure, -5.4 +/- 5.3 mmHg for Korotkoff phase 4 (P less than .001), and 0.87 +/- 3.7 mmHg for phase 5 diastolic blood pressure. The TM-2420 ambulatory monitor provides reliable estimates of systolic and Korotkoff phase 5 diastolic blood pressures during pregnancy.     

Amnioinfusion for meconium-stained liquor

Amnioinfusion reduces the risk of meconium aspiration by the infants of women with thick meconium staining of the amniotic fluid. The benefits are clear in facilities with high baseline rates of meconium aspiration, and are therefore likely to outweigh the risk of uncommon but serious maternal side-effects. Larger randomized trials are needed to determine more precisely the relative risks and benefits in facilities with low baseline rates of meconium aspiration. The addition of antibiotics to the infusate has not been shown to reduce the risk of sepsis related to meconium.     

Calcium supplementation to prevent pre-eclampsia--a systematic review.

BACKGROUND: Calcium supplementation during pregnancy may prevent high blood pressure and preterm labour. OBJECTIVE: To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child adverse outcomes. DESIGN: A systematic review of randomised trials that compared supplementation with at least 1 g calcium daily during pregnancy with placebo. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register (October 2001) and the Cochrane Controlled Trials Register (Issue 3, 2001) were searched and study authors were contacted. DATA COLLECTION AND ANALYSIS: Eligibility and trial quality were assessed. Data were extracted and analysed. MAIN RESULTS: There was a modest reduction in the risk of pre-eclampsia with calcium supplementation (relative risk (RR) 0.68, 95% confidence interval (CI): 0.57-0.81). The effect was greatest for women at high risk of hypertension (RR 0.21, 95% CI: 0.11-0.39) and those with low baseline calcium intake (RR 0.32, 95% CI: 0.21-0.49). There was no overall effect on the risk of preterm delivery, although there was a reduction in risk among women at high risk of hypertension (RR 0.42, 95% CI: 0.23-0.78). There was no evidence of any effect of calcium supplementation on stillbirth or death before discharge from hospital. There were fewer babies with birthweight < 2,500 g (RR 0.83, 95% CI: 0.71-0.98). In one study, childhood systolic blood pressure > 95th percentile was reduced (RR 0.59, 95% CI: 0.39-0.91). CONCLUSIONS: Calcium supplementation appears to be beneficial for women at high risk of gestational hypertension and in communities with low dietary calcium intake. These benefits were confined to several rather small trials, and were not found in the largest trial to date, conducted in a low-risk population. Further research is required.     

Heart rate changes after acute fetal haemorrhage--a basis for the pathophysiology of the sinusoidal pattern

Our study was designed to obtain information about the prevalence of breast-feeding among rural and urban Blacks, to determine whether the number of women providing early supplementary feeding has increased over a 4-year period, and to discover groups at particular risk of failure to breast-feed optimally. Women attending child health clinics were interviewed. Over 95% had commenced breast-feeding, but only 50% were still doing so after 5--8 weeks. Women uncertain of whether or not to breast-feed and those unsuccessful on a previous occasion are as likely to commence breast-feeding as are other groups, but are likely to introduce early supplementation. Improvements in hospital and clinic practice as regards a greater emphasis on health education, early suckling and the avoidance of supplementary feeding in neonates may have contributed to the slight improvement in breast-feeding practices seen over the 4-year period studied.