Uterine atony prophylaxis with carbetocin versus oxytocin and the risk of major haemorrhage during caesarean section: A retrospective cohort study.

Carbetocin and oxytocin are commonly recommended agents for active management of the third stage of labour. Evidence is inconclusive whether either one more effectively reduces the occurrence of important postpartum haemorrhage outcomes at caesarean section. We examined whether carbetocin is associated with a lower risk of severe postpartum haemorrhage (blood loss ≥ 1000 ml) in comparison with oxytocin for the third stage of labour in women undergoing caesarean section. This was a retrospective cohort study among women undergoing scheduled or intrapartum caesarean section between 1 January 2010 and 2 July 2015 who received carbetocin or oxytocin for the third stage of labour. The primary outcome was severe postpartum haemorrhage. Secondary outcomes included blood transfusion, interventions, third stage complications and estimated blood loss. Outcomes were examined overall and by timing of birth, scheduled versus intrapartum, using propensity score-matched analysis. Among 21,027 eligible participants, 10,564 women who received carbetocin and 3836 women who received oxytocin at caesarean section were included in the analysis. Carbetocin was associated with a lower risk of severe postpartum haemorrhage overall (2.1% versus 3.3%; odds ratio, 0.62; 95% confidence interval 0.48 to 0.79; P < 0.001). This reduction was apparent irrespective of timing of birth. Secondary outcomes also favoured carbetocin over oxytocin. In this retrospective cohort study, the risk of severe postpartum haemorrhage associated with carbetocin was lower than that associated with oxytocin in women undergoing caesarean section. Randomised clinical trials are needed to further investigate these findings.

A survey of anaesthetists on uterotonic usage practices for elective caesarean section in Australia and New Zealand.

Prophylactic administration of uterotonics ensures adequate uterine contraction at elective caesarean section to prevent substantial haemorrhage. Royal College of Obstetricians and Gynaecologists guidelines advise the administration of oxytocin at 5 IU as a 'slow bolus' but there are variations in clinical practice. This study aimed to determine the beliefs and uterotonic usage practices at elective caesarean section by surveying anaesthetist members of the Obstetric Anaesthesia Special Interest Group in Australia and New Zealand. Questionnaires were emailed to Obstetric Anaesthesia Special Interest Group members and the response rate was 33%, with analysis of 279 completed reports. Oxytocin was the most commonly used first-line uterotonic, but extensive variation in oxytocin bolus use was identified. Thirty-eight per cent of anaesthetists routinely administered Royal College of Obstetricians and Gynaecologists guideline-recommended 5 IU, whereas 38% favoured low dose (<5 IU), 10% high dose (≥10 IU) oxytocin and 13% carbetocin (100 µg). More than 50% felt the evidence was weak for guideline-recommended 5 IU. Wide variation in the duration of oxytocin administration was also identified. Fifty-eight per cent of anaesthetists routinely gave follow-up oxytocin infusions, most commonly at 40 IU over 4 hours, but there was significant variation in the dosage (10-40 IU) and administration duration (1 hour to ≥6 hours). In conclusion, there is significant variation in oxytocin usage practices at elective caesarean section among Australian and New Zealand anaesthetists. This variation may be due to a lack of strong evidence to guide practice. This emphasises the need for high quality trials in this clinically important area.

Repeat propofol anesthesia does not exacerbate plaque deposition or synapse loss in APP/PS1 Alzheimer's disease mice.

BACKGROUND: There is increasing interest in whether anesthetic agents affect the risk or progression of Alzheimer's disease (AD). To mitigate many of the methodological issues encountered in human retrospective cohort studies we have used a transgenic model of AD to investigate the effect of propofol on AD pathology. METHODS: Six month-old amyloid precursor protein/presenilin 1 (APP/PS1) transgenic AD mice and control mice were exposed to 3 doses of propofol (200 mg/kg) or vehicle, delivered at monthly intervals. RESULTS: There was no difference in the extent of ß-amyloid (Aß) immunolabeled plaque deposition in APP/PS1 mice in vehicle versus propofol treatment groups. We also detected no difference in plaque-associated synapse loss in APP/PS1 mice following repeat propofol exposure relative to vehicle. Western blotting indicated that there was no difference in post-synaptic density protein 95, synaptophysin or glutamic acid decarboxylase 65/67 expression in control or APP/PS1 mice subjected to repeat propofol treatment relative to vehicle. CONCLUSIONS: These data suggest that repeat propofol anesthesia may not exacerbate plaque deposition or associated synapse loss in AD. Interestingly, this data also provides some of the first evidence suggesting that repeat propofol exposure in adult wild-type mice does not result in robust long-term alterations in the levels of key excitatory and inhibitory synaptic markers.

Obstetric and anesthetic management of severe congenital myasthenia syndrome.

The congenital myasthenia syndromes form a heterogeneous group of genetic diseases characterized by defective neuromuscular transmission. Although they have muscle fatigability in common with the acquired immune myasthenia syndrome, there are important pathophysiological, diagnostic, management and progression pattern differences between them. We report the management of a 28-yr-old patient with longstanding congenital myasthenia syndromes, who underwent an elective cesarean delivery under spinal anesthesia. Muscle imbalance plus weakness-related scoliosis and chronic respiratory failure complicated her management. Ultrasonography was used to facilitate the spinal anesthetic. Intraoperative noninvasive positive pressure ventilation maintained lung volumes effectively and prevented deterioration in respiratory function.