The effects of routine oxytocic administration in the management of the third stage of labour: an overview of the evidence from controlled trials

Summary. Recent claims that routine active management of the third stage of labour increases rather than decreases maternal and neonatal morbidity have prompted us to conduct a systematic review of the relevant controlled trials. In this paper we have analysed data derived from a total of nine published reports of controlled trials in which an oxytocic drug was compared with either a placebo or no routine prophylactic. Oxytocic drugs used routinely appear to reduce the risk of postpartum haemorrhage by about 40% (typical odds ratio 0·57, 95% confidence interval 0·44–0·73) implying that for every 22 women given such an oxytocic, one postpartum haemorrhage could be prevented. The available data are insufficient to assess the possible effects of this policy on the incidence of retained placenta, hypertension and other possible adverse effects.     

Classical versus low-segment transverse incision for preterm caesarean section: maternal complications and outcome of subsequent pregnancies

Summary. In a retrospective, controlled, follow-up study of 326 women who had a primary preterm caesarean section, the risks of postoperative maternal morbidity and uterine rupture or dehiscence in subsequent pregnancies were investigated in relation to the mode of incision (classical compared with low-segment transverse incision). The classical incision was associated with a higher frequency of postpartum fever in the immediate postoperative period (16% compared with 6%, P<0·01). Of the 326 patients reviewed 286 (88%) were contacted for information about subsequent pregnancies. Information was obtained for 70 pregnancies subsequent to a classical caesarean section, and 71 pregnancies subsequent to a low-segment transverse caesarean section, which had continued for more than 20 weeks gestation. Of the pregnancies after the classical operation 13% had abnormal scars compared with none of those after the low-segment transverse operation ( P =0·0014). The frequency of scar dehiscence was 6% after a classical scar compared with none after a low-segment transverse scar (P=0·0581).     

Vecuronium titration for muscle relaxation in myotonic dystrophy

A 14-year-old boy with pronounced myotonic dystrophy and cardiac malformation had a normal ED₉₅ (53 μg·kg^?1) of vecuronium, whereas the recovery index (25-75% twitch recovery) was three times as long as in the absence of neuromuscular disease. We conclude that in young patients with dystrophic muscle disease individual titration of the muscle relaxant with the aid of a nerve stimulator does not preclude a considerable delay in the recovery of neuromuscular transmission.     

Working memory and preparation elicit different patterns of slow wave event-related brain potentials

Some event-related brain potential (ERP) studies of working memory have used delayed match-to-sample designs in which a stimulus (S1) is held in memory for comparison with a subsequent stimulus (S2). During the S1-S2 interval, ERP slow negativities varied with both the type and amount of material held in working memory. One interpretation is that these slow waves index working memory operations. An alternative explanation is that they only reflect general preparatory processing for the response to S2. To decide between these explanations, we used two visual processing tasks that required similar preparation for S2. In one task, visual memory rehearsal operations were required. During the S1-S2 interval, there were clear differences between the amplitudes, topographies, and the effect of information load on the slow waves in the two tasks, thus ruling out preparation only as an explanation.     

NORMALIZED STRESS–STRAIN RELATIONSHIP IN HUMAN HAIR PERTURBATION BY HYPOTHYROIDISM

SUMMARY.— A short review is given of the observations which have been made on the mechanical properties of human hair under axial tension.
Stress–strain curves of dry single fibres of human hair from patients with hypothyroidism and acromegaly revealed a distinctive alteration in the high yield region. The biophysical basis for this anomalous behaviour is not known.
Attention is directed to the potential value of further studies of the physical characteristics of hair with special reference to mass screening programmes for evidence of disease. This aim is furthered by the technique introduced in this paper for distinguishing the abnormal from the normal.     

CONTINUOUS NEGATIVE CHEST-WALL PRESSURE THERAPY FOR ASSISTING VENTILATION IN OLDER CHILDREN WITH PROGRESSIVE RESPIRATORY INSUFFICIENCY1

Abstract. Continuous negative chest-wall pressure (CNP) was used to assist ventilation in 14 children, 6 months to 14 years of age, who had progressive respiratory insufficiency caused by diffuse bilateral alveolar disease. Before the start of CNP therapy, each child had a respiratory rate>50/min, arterial oxygen tension (PaO₂)<70 mmHg (FIO₂≥50%), and arterial carbon dioxide tension (PaCO₂)<45 mmHg. The mean intrapulmonary right-to-left shunt was 28.7±3.8%. Within 6 hours after therapy was started, PaO₂ increased from 55.4±15.9 to 81.6±17.7 mmHg (p<0.005). This improvement was sustained and within 24 hours permitted a decrease in fractional concentration of inspired oxygen (FIO₂) from 51.8±6.2 to 41.0±8.4% (p<0.001) and in respiratory rate from 78.1±23.0 to 56.4±21.3 (p<0.01). There was a concomitant decrease in intrapulmonary right-to-left shunt. Four of the 14 patients developed pneumothorax that was successfully decompressed. Ten patients survived. These observations establish CNP therapy as an effective means of improving arterial oxygenation in spontaneously breathing older children. Of added significance, this mode of therapy eliminates the need for endotracheal intubation and prolonged use of muscle relaxants and sedatives. It also minimizes exposure to high FIO₂, thereby minimizing the hazards of pulmonary oxygen toxicity.     

The fitness of human translocation carriers

A simple method to estimate the mean fitness of human translocation carriers is described. The method is based on information about the inheritance pattern of the translocations. This kind of data can be obtained from the surveys of the chromosome constitutions of new-born babies. The following fitness estimates are obtained: D/D translocation carriers, 0-94; D/G translocation carriers, 0-83; and reciprocal translocation carriers, 0-67. The estimates are rather uncertain due to the scarcity of information, but they are consistent with the expected results. More accurate estimates will be obtained in the future when more data on translocation carriers are available and the cytological classification of the different translocations becomes more exact.