British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Convective warming combined with vasodilator therapy accelerates core rewarming after coronary artery bypass surgery.
In a prospective, randomized, controlled study, we have investigated the effect of forced air warming on the rate of change of nasopharyngeal and rectal temperatures in 20 patients after coronary artery bypass grafting. All patients had nasopharyngeal temperatures less than 36 degrees C on arrival in the intensive care unit and received an infusion of glyceryl trinitrate 15 mg h-1, but none received inotropes. ⋯ The rates of increase in nasopharyngeal temperature were 0.4 and 0.95 degrees C h-1, respectively, in the control and Bair Hugger groups (P < 0.01) during the first 2 h after operation. Over the same period of time, rectal temperatures increased at a rate of 0.25 and 0.75 degrees C h-1 in the control and Bair Hugger groups, respectively (P < 0.01).
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Randomized Controlled Trial Clinical Trial
Postoperative analgesia by continuous extradural infusion of ropivacaine after upper abdominal surgery.
Ropivacaine is a new local anaesthetic with advantages that suggest an important role in the provision of postoperative analgesia. The main aim of this study was to investigate the dose-response relationship of extradural infusion of ropivacaine. We studied 36 ASA I-III patients undergoing upper abdominal surgery during general anaesthesia and extradural block (catheter insertion at T6-9) using 0.5% ropivacaine in a randomized, double-blind study. ⋯ Pain on coughing was significantly less in all ropivacaine groups than in the saline group after 4 h infusion (medians: saline 67 mm; 0.1% ropivacaine 44 mm; 0.2% ropivacaine 33 mm; 0.3% ropivacaine 0 mm) and for 0.2% and 0.3% ropivacaine at later times. Motor block was negligible throughout the infusion. Patient satisfaction was higher in the 0.2% and 0.3% ropivacaine groups than in the two other groups.
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Randomized Controlled Trial Clinical Trial
Effect of apparatus on functional residual capacity.
As the route of breathing and use of airway apparatus such as mask, mouthpiece and noseclip can alter breathing pattern, this study has used the helium dilution method to estimate the effects of mouthpiece and mask breathing on functional residual capacity (FRC) in the supine position, and the change in FRC that occurs between the sitting and supine positions while breathing by mouthpiece. In 13 normal subjects, breathing by mouthpiece, FRC was smaller, by a median of 1.07 litre (interquartile values 0.73-1.43 litre) in the supine compared with the sitting position (P < 0.01), but residual volume (RV) did not change significantly. FRC measured in the supine position was significantly greater when breathing by mask than by mouthpiece (0.25, 0.04-0.38 litre) and RV was greater by similar amounts (0.20, -0.02 to 0.49 litre). This difference may result from increased inspiratory activity while breathing via the mask.
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We have studied rats with chronically implanted subarachnoid catheters. Xylazine, an alpha 2 adrenoceptor agonist, was injected intrathecally and nociceptive thresholds measured at two skin sites: the tail and the neck. Intrathecal xylazine (dose range 24.3-389 nmol) produced increases in electrical thresholds for nociception in the tail without any change in the neck; this observation suggested that the antinociceptive action of this drug was confined to the caudal part of the spinal cord responsible for tail innervation. ⋯ In contrast, the antinociceptive effects of intrathecal xylazine were not affected by concurrent administration of opioid or GABAA antagonists. We conclude that intrathecal xylazine produced spinally mediated antinociceptive effects by combination with spinal cord alpha 2 adrenoceptors and that neither opioid nor GABA-containing propriospinal neurones were involved in the mediation of this effect. However, alpha 2 adrenoceptors in the spinal cord appear to be involved with antinociception produced by intrathecal fentanyl.