British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Anaesthesia with propofol decreases FMLP-induced neutrophil respiratory burst but not phagocytosis compared with isoflurane.
Propofol has been reported to produce a dose-dependent inhibition of phagocytosis and superoxide anion production during the respiratory burst (RB) of polymorphonuclear cells (PMNs) in vitro. In this randomized, blinded study, these two parameters were compared during propofol or isoflurane anaesthesia in patients undergoing elective interventional embolization of cerebral arterio-venous malformations. Anaesthesia was performed with continuous intravenous propofol 6-8 mg kg-1 h-1 (n = 15) or isoflurane 0.8-1.0% end tidal (n = 15). ⋯ The percentage of PMN with RB activity following TNF-alpha/FMLP stimulation was significantly reduced after 2 h (80.9% (24.2%); P < 0.05) and 4 h (53.7% (27.3); P < 0.05) of anaesthesia with propofol compared with the values before induction. This effect of propofol anaesthesia was significantly different from the effect of isoflurane anaesthesia. In contrast to published in vitro results, 4 h of anaesthesia with propofol did not reduce the phagocytotic capacity of human blood PMN more than isoflurane anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intravenous opioids reduce airway irritation during induction of anaesthesia with desflurane in adults.
Desflurane is not used for the induction of anaesthesia despite its favourable pharmacokinetic characteristics because it causes airway irritation. We investigated whether pretreatment with i.v. narcotics reduced unwanted effects. One hundred and eighty adults were randomized to three groups (60 per group) to receive i.v. saline, fentanyl 1 microgram kg-1 and morphine 0.1 mg kg-1, respectively, before inhalational induction with desflurane in nitrous oxide and oxygen. ⋯ Laryngospasm developed in 11.7% of controls compared with 3.3 and 1.7% in the fentanyl and morphine groups, respectively. More patients in the control group had excitatory movements (46.7%) than in the fentanyl (16.7%) and morphine (8.3%) groups. These results demonstrate that i.v. opioids reduce airway irritability significantly during inhalational induction with desflurane in adults.
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Tidal ventilation causes within-breath oscillations in alveolar oxygen concentration, with an amplitude which depends on the prevailing ventilator settings. These alveolar oxygen oscillations are transmitted to arterial oxygen tension, PaO2, but with an amplitude which now depends upon the magnitude of venous admixture or true shunt, QS/QT. We investigated the effect of positive end-expiratory pressure (PEEP) on the amplitude of the PaO2 oscillations, using an atelectasis model of shunt. ⋯ Clear oscillations of PaO2 were seen even at the lowest mean PaO2, 9.5 kPa. Conventional respiratory models of venous admixture predict that these PaO2 oscillations will be reduced by the steep part of the oxyhaemoglobin dissociation curve if a constant pulmonary shunt exists throughout the whole respiratory cycle. The facts that the PaO2 oscillations occurred at all mean PaO2 values and that their amplitude increased with increasing PEEP suggest that QS/QT, in the atelectasis model, varies between end-expiration and end-inspiration, having a much lower value during inspiration than during expiration.
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Randomized Controlled Trial Comparative Study Clinical Trial
Influence of different colloids on molecular markers of haemostasis and platelet function in patients undergoing major abdominal surgery.
Synthetic colloids have been reported to cause haemorrhagic complications. The effects of perioperative volume replacement with 4% gelatin (n = 20), 6% low-molecular weight (LMW) hydroxyethyl starch (HES) (Mw: 70,000 dalton; HES 70/0.5; n = 20) and 6% medium-molecular weight (MMW) HES (Mw: 200,000 dalton; HES 200/0.5; n = 20) on haemostasis were assessed in patients undergoing major abdominal surgery. Volume was administered to keep central venous pressure (CVP) between 10 and 14 mm Hg. ⋯ Factor VIII and von Willebrand factor (vWF) also increased in all groups beyond the normal range, showing the significantly highest increase in the gelatin-treated group (VIII: from 173 (36) to 266 (33) U dl-1; vWF: from 164(33) to 238 (31) U dl-1). Platelet function remained within the normal range and without group differences throughout the study period. We can conclude that all three solutions can be used safely in patients undergoing major abdominal surgery with regard to the haemostatic process.
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Randomized Controlled Trial Comparative Study Clinical Trial
Motor block during patient-controlled epidural analgesia with ropivacaine or ropivacaine/fentanyl after intrathecal bupivacaine for caesarean section.
We compared patient-controlled epidural analgesia (PCEA) with ropivacaine alone or combined with fentanyl in terms of analgesic efficacy, motor weakness and side-effects in patients who had received spinal anaesthesia for elective Caesarean section. ASA I patients received combined spinal-epidural anaesthesia and were randomly assigned, in a double-blind study, into two groups after operation: group R (n = 23) received PCEA ropivacaine 0.1%, bolus 5 mg, lock-out 15 min, 3 mg h-1 background infusion, and group RF (n = 24) received PCEA 0.1% ropivacaine/fentanyl 2 micrograms ml-1 at identical settings. Pain and satisfaction on a 100 mm visual analogue scale (VAS) and side-effects were noted. ⋯ Analgesic consumption was less in RF (P = 0.041), but there was no difference in time to first request for supplementary analgesia. Patient satisfaction with postoperative analgesia (mean (SD)) was higher in RF (79 (23) vs 57 (29) mm, P = 0.045). Caution should be exercised using ropivacaine PCEA after spinal bupivacaine for Caesarean section, because its reputed motor-sparing property may be unreliable.