MacclesfieldSUMMARY The percutaneous absorption of chlorhexidine during its routine use in topical antiseptic preparations used in umbilical cord care was investigated by determining plasma chlorhexidine concentrations at ages 5 and 9 days. These showed that percutaneous absorption of chlorhexidine occurred in preterm neonates treated with a 1 % solution of chlorhexidine in ethanol, but not in term infants similarly treated, or in preterm infants treated only with a dusting powder containing 1 % chlorhexidine and 3 % zinc oxide.

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SUMMARY Pethidine or an epidural injection of bupivacaine are common forms of obstetric analgesia in Britain. Bupivacaine has been thought to have little effect on the fetus, but neurobehavioural studies have cast doubt on this. We therefore investigated the elimination of these drugs by babies in similar population groups. Bupivacaine was largely eliminated in just over one day, while pethidine required between 2 and 6 days. This could account for the persisting depression in babies whose mothers had received pethidine.At present in Britain the most commonly used analgesics in labour are pethidine or epidural bupivacaine. Pethidine is known to depress the respiration of the newborn baby (Schnider and Moya, 1964). This effect was least if the analgesic was given in a single dose within one hour of delivery. Bupivacaine, though known to cross the placenta (Belfrage et al., 1975a), was thought to have little effect on the baby. Neurobehavioural scoring has given new information on the assessment of these drugs. Pethidine decreased the newborn response to behavioural tests as did lignocaine and mepivacaine (Brackbill et al., 1974;Scanlon et al., 1974). We have studied the elimination of pethidine and bupivacaine in the first few days of life. Method There were 19 mothers in each group. All were aged between 20 and 35 years. The mean weight of the mothers given bupivacaine was 73-4 kg (± 12 1 SD) and duration of labour averaged 6 hours 40 minutes. The mean weight of the group of mothers given pethidine was 72-9kg (±8 5SD) and average duration of labour was 6 hours 58 minutes. None had cardiovascular or respiratory disease. The purpose of the study was explained in detail to each woman and her consent obtained. The babies were all normal and of more than 36 weeks' gestation, mean birthweight being 3 *4 kg (±0 33 SD). Analgesics were given as required. 16 mothers received a single dose of pethidine 150 mg intramuscularly and in 3 this was repeated once. Bupivacaine was administered epidurally in 0 *25 % concentration, Received 24 December 1976 *We regretfully report the death of Miss Cooper on April 15. Editors. usually in 10 ml doses, and the total amount necessary for patient comfort ranged from 25-185 mg with an average of 84 mg. After a pilot study it seemed inappropriate to take blood samples for each drug at the same time intervals. Therefore, in the pethidine group samples were taken at delivery from the mother and from cord blood, then at 2, 4, 8, 12, 24 hours and at 2, 3, 4, and 5 days from the baby. With the mothers receiving bupivacaine samples were taken at delivery, then at 2, 4, 8, 12, and 24 hours. Delivery samples were taken from the maternal antecubital vein and the umbilical vein. Samples were obtained from the babies by heel prick.Pethidine was extracted by a method described by Beckett and Taylor (1967), and bupivacaine as described by Reynolds and Beckett (1968). After extraction from plasma the drugs were estimated by gas chromatography using a nitrogen detector.

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. (1970). Archives of Disease in Childhood, 45, 506. Plasma calcium and magnesium in newborn babies. Normal values for plasma calcium and magnesium levels during the first week of life, in breast-and bottle-fed babies, have been determined. It has been shown on the sixth day that plasma levels of calcium, magnesium, and protein are all significantly lower in bottle-fed babies than in breast-fed babies, while the reverse is true of the plasma inorganic phosphorus.The normal babies have been compared with 30 babies who had convulsions, beginning towards the end of the first week of life. In only six of the babies was the plasma calcium outside our normal range and only four had abnormally low magnesium levels. As so many of these babies had calcium and magnesium levels within the normal range it must seriously be questioned whether hypocalcaemia or hypomagnesaemia could have been the sole cause of the convulsions.In order to establish normal values for the first week of life, calcium and magnesium have been measured in samples of plasma for normal infants who were either breast-or bottle-fed.Convulsions beginning on the 5th to 8th days of life are often attributed to hypocalcaemia (Bakwin, 1937) or hypomagnesaemia (Davis, Harvey, and Yu, 1965). A group of babies with convulsions at the end of the first week has been compared with the normal infants.Material and Methods Two maternity units were used for this survey. The first series was conducted at Hammersmith Hospital from June to September 1967; the blood was collected immediately before the 9 a.m. feed from normal babies on the first seven days of life. Samples obtained from 85 babies were not consecutive though most babies were bled more than once. Heel-prick samples were obtained without squeezing and were centrifuged and separated immediately; any grossly haemolysed samples were discarded. Heparin was used as an anticoagulant. The babies' weights ranged from 2300 to 4460 g., and their gestational ages from 38 to 42 weeks. They were either entirely breast fed, apart from an initial feed of glucose and water, or were fed on an evaporated milk formula ('Carnation Milk'). This was diluted 1 part with 21 parts of water, and given in volumes of 90-160 ml./kg. per 24 hours on the second day, increasing gradually to 140-160 ml./kg. per 24 hours on the sixth day. In this dilution the milk contained: phosphorus 67 mg./100 ml.; calcium 76 mg./100 ml., and vitamin D 28 I.U./100 ml.