International journal of obstetric anesthesia
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Int J Obstet Anesth · Jan 1999
Transfer of lidocaine across the dual perfused human placental cotyledon.
Factors affecting lidocaine transfer across the normal term human placenta were studied using the dual perfused isolated single cotyledon. Experiments were performed using perfusates which provided equal protein binding in both the maternal and fetal circuits as well as perfusates that approached the actual in vivo maternal/fetal protein binding gradient. Additional experiments were performed to investigate the effects of increasing maternal lidocaine concentration (5, 10, 40, 80 microg/mL) on maternal to fetal (M-->F) lidocaine transfer across the human placenta. ⋯ When protein binding was similar in the two circuits, M-->F transfer ratios (lidocaine transfer/antipyrine transfer) were significantly lower than the transfer ratios seen in the F-->M direction (0.59+/-0.04 versus 0.84+/-0.06, P<0.05). Transfer ratios (M-->F: 0.83+/-0.06, F-->M: 0.96+/-0.06) were not reduced when the physiological maternal/fetal protein binding gradient was present. Lidocaine transfer was not diminished by increasing maternal concentrations and, in contrast to bupivacaine, was not significantly affected by its binding.
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Obstetric audit is multidisciplinary, but maternal mortality data represent the only national obstetric anaesthetic audit currently available in the UK. Maternity and neonatal audit is progressing towards the collection of both numerator and denominator data in order to compare local, regional and national figures. Obstetric anaesthetists as a professional group play a significant role in maternity care and have in the past developed a minimum data set. ⋯ Since local and regional obstetric anaesthesia data collection systems are available, albeit in various manual or computerized forms, this is an achievable target. A standard maternity and neonatal data set which incorporates obstetric anaesthetic clinical items could offer a qualitative comparison of process variables and outcome, but should be under professional anaesthetic control. In addition, the process may enable professional standards to be defined and tested so that high quality obstetric anaesthetic care can be maintained.
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A new technique is described for delivering combined spinal epidural anaesthesia. The disadvantages of the needle-through-needle technique and the two-needle techniques are discussed. The new technique is a modification of the two-needle technique. ⋯ The spinal needle obturator is then removed and intrathecal injection performed. This technique avoids problems associated with placing an epidural catheter after an intrathecal injection and the potential problem of placing a spinal needle when an epidural catheter has already been placed. This technique requires further evaluation.
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Int J Obstet Anesth · Jan 1999
The occupational exposure of midwives to nitrous oxide - a comparison between two labour suites.
The study of midwives' occupational exposure to nitrous oxide in a poorly ventilated maternity unit in 1992 was instrumental in ensuring that the replacement building had Department of Health approved ventilation. We have repeated the study in the new unit. ⋯ This difference was significant amongst those midwives who spent a greater time looking after women using Entonox and thus were more at risk from its detrimental effects. We discuss these findings and the ramifications for other maternity units under the new COSHH regulations.
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Int J Obstet Anesth · Jan 1999
Administration of drugs outside of Product Licence: awareness and current practice.
An interactive audience response system was used to collect information from members of the Obstetric Anaesthetists' Association at the 1997 Annual Meeting about the drug use that is unsupported by the Product Licence. The responses confirm that both licensed and unlicensed drugs are widely used in clinical practice outside the limitations imposed by Product Licence. ⋯ A majority of audience members expressed a view that the OAA should play a pro-active role, either by polling members about their current practice, or by issuing guidelines on reasonable drug practice in obstetric anaesthesia, or both. Potential implications of these are discussed.