Patient-controlled analgesia using remifentanil in the parturient with thrombocytopaenia.

Patient-controlled intravenous remifentanil was used to provide analgesia in labour for three thrombocytopaenic women. The most successful regimen comprised a patient-demand bolus of 0.5 microg x kg(-1) with a lockout period of 2-3 min, allowing for a successful demand with each contraction. There was an initial period during which the patient learned to anticipate the next contraction and to deliver a bolus about 30 s beforehand; subsequently the remifentanil provided excellent analgesia, with a range of consumption of 426-1050 microg x h(-1). Apart from one episode of maternal sedation and fetal heart rate decelerations resulting from an excessive demand bolus, mothers and neonates tolerated the remifentanil without sequelae. Owing to rapid metabolism by tissue esterase, the use of remifentanil allows adequate doses of opioid to be administered to the mother to achieve good analgesia, without its accumulation in the fetus.

Single space combined spinal-extradural technique for analgesia in labour.

We have used the single space combined spinal-extradural technique for mothers requesting analgesia in labour. Intrathecal plain bupivacaine 5 mg produced a median time to analgesia of 3 min. There was inadequate abdominal analgesia after 10 min in 16% of recipients, although all had good perineal analgesia. The median height of block was T8 (range T4-L2) and mean duration of analgesia 72 (SD 21) min. Hypotension occurred in two of 30 mothers, but responded to fluids and ephedrine. There were no post-spinal headaches. This technique is suitable for those parturients requesting analgesia in active labour who may not have time to achieve extradural analgesia before delivery. The extradural catheter is used to improve analgesia if the subarachnoid block is inadequate, or if labour continues beyond the duration of the subarachnoid block.

Percutaneous insertion of Hickman-type catheters.

Hickman lines may be used for long-term venous access in patients having chemotherapy, bone marrow transplantation, parenteral nutrition, or in others needing prolonged venous access. This article describes the technique of percutaneous insertion, some of the problems that may be encountered at insertion, and ways of minimizing these problems.

A low flow open circle system for anaesthesia. Part I: Laboratory evaluation at normal and high frequencies.

A circle breathing system was connected by deadspace tubing to an open system valveless ventilator. The minimum volume of this tubing, required to prevent dilution of anaesthetic gas in the breathing system by the driving gas of the ventilator, was determined at frequencies of 15, 30, 60, 100 and 150 breaths/minute, with tidal volumes that ranged from 100 to 1100 ml and a fresh gas supply to the circle system of 1, 2 and 4 litres/minute. At 15 breaths/minute, tidal volumes equal to or less than the deadspace volume could be used safely without any mixing with the ventilator driving gas, when a fresh gas flow of 2 litres/minute or above is supplied to the circle system. At 1 litre/minute of fresh gas flow, mixing occurred at tidal volumes less than the deadspace volume. Mixing of gas occurred in the system at frequencies greater than 30 breaths/minute even when the tidal volume was much less than the deadspace volume. However, at high frequencies of ventilation, since the tidal volume requirement decreases, deadspace tubing with a safe internal volume, that is greater than 600 ml, may be used up to 100 breaths/minute.