British journal of anaesthesia
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Case Reports
Patient-controlled analgesia in labour using remifentanil in two parturients with platelet abnormalities.
Two term parturients with documented platelet abnormalities presented to the delivery suite in labour. Because regional analgesic techniques were contraindicated, we elected to use patient-controlled i.v. remifentanil for pain relief. ⋯ There were no adverse neonatal sequelae. If there are facilities to monitor the neonate and mother, this method of analgesia may prove useful in those patients where regional techniques are not possible, but further research is needed to ascertain its safety and appropriateness in such circumstances.
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Case Reports
Thoracic paravertebral block: radiological evidence of contralateral spread anterior to the vertebral bodies.
We report contralateral spread of contrast medium anterior to the vertebral bodies after injection of contrast through a thoracic paravertebral catheter that was used to manage pain in a patient with multiple fractured ribs. We review the literature and propose that the anatomical basis for this observation is spread in the extrapleural compartment of the thoracic paravertebral space along the subserous fascial plane.
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Comparative Study
Biologically variable ventilation prevents deterioration of gas exchange during prolonged anaesthesia.
We have studied the time course of changes in gas exchange and respiratory mechanics using two different modes of ventilation during 7 h of isoflurane anaesthesia in pigs. One group received conventional control mode ventilation (CV). The other group received biologically variable ventilation (BVV) which simulates the breath-to-breath variation in ventilatory frequency (f) that characterizes normal spontaneous ventilation. ⋯ The modulation file used to control the ventilator for BVV used an inverse power law frequency distribution (I/fa with a = 2.3 +/- 0.3). After 7 h, at a similar delivered minute ventilation, significantly greater PaO2 (mean 72.3 (SD 4.0) vs 63.5 (6.5) kPa) and respiratory system compliance (1.08 (0.08) vs 0.92 (0.16) ml cm H2O-1 kg-1) and lower PaCO2 (6.5 (0.7) vs 8.7 (1.5) kPa) and shunt fraction (7.2 (2.7)% vs 12.3 (6.2)%) were seen with BVV, with no significant difference in peak airway pressure (16.3 (1.2) vs 15.3 (3.7) cm H2O). A deterioration in gas exchange and respiratory mechanics was seen with conventional control mode ventilation but not with BVV in this experimental model of prolonged anaesthesia.