Comparison of the analgesic efficacy and respiratory effects of morphine, tramadol and codeine after craniotomy.

Pain after craniotomy remains a significant problem. The effect of morphine and tramadol patient-controlled analgesia (PCA) on arterial carbon dioxide tension is unknown in patients having such surgery. Sixty craniotomy patients were randomly allocated to receive morphine PCA, tramadol PCA or codeine phosphate 60 mg intramuscularly. Baseline values of pain score (0-10), sedation and arterial carbon dioxide tension were recorded at the time of first analgesic administration and at 30 min, 1, 4, 8, 12, 18 and 24 h. Patient satisfaction was assessed at 24 h. There were no differences in arterial carbon dioxide tension or sedation between groups at any time, but in all three groups some patients had rises greater than 1 kPa. Morphine produced significantly better analgesia than tramadol at all time points (p < 0.005) and better analgesia than codeine at 4, 12 and 18 h. Patients were more satisfied with morphine than with codeine or tramadol (p < 0.001). Vomiting and retching occurred in 50% of patients with tramadol, compared with 20% with morphine and 29% with codeine.

Predictive value of IL-18 and SC5b-9 for neurocognitive dysfunction after cardiopulmonary bypass.

BACKGROUND: Neurological injury after cardiopulmonary bypass (CPB) continues to be a major problem after cardiac surgery. The aim of this study was to investigate the predictive value of Interleukin-18 (IL-18) and SC5b-9 as biochemical markers of neurocognitive dysfunction after cardiac surgery. METHODS: A total of 30 patients undergoing elective cardiac surgery using CPB were recruited. Blood samples were obtained for IL-18 and SC5b-9 concentrations before induction, 24, 48, 72, 96 and 120 h post-CPB and 6 weeks after operation. In addition, patients underwent a standard battery of neuropsychometric tests before operation and at day 5 and 6 weeks after operation. RESULTS: Serum concentration of IL-18, but not SC5b-9, was significantly different between patients with and without neurocognitive dysfunction; serum IL-18 concentration significantly increased in patients with neurocognitive dysfunction (P = 0.018). Neurological outcome was significantly dependent on peak difference in IL-18 concentration at day 5 (P = 0.033), but not on peak difference in SC5b-9 concentration (P = 0.16). Eight patients had neurocognitive dysfunction at day 5 and three had neurocognitive dysfunction at 6 weeks. In a very small number of patients, no significant association was demonstrated between IL-18 or SC5b-9 concentrations and neurocognitive dysfunction at 6 weeks. CONCLUSIONS: IL-18 has the potential as a useful marker of neurological dysfunction, requiring further investigation.

Haemodynamic effects of the prone position: a comparison of propofol total intravenous and inhalation anaesthesia.

The haemodynamic changes of the prone position were investigated in 40 ASA I-II patients undergoing lumbar spine surgery. Patients were randomly assigned, following propofol intravenous induction, to receive maintenance of anaesthesia using either isoflurane 1-1.2% in air or target controlled propofol 3 microg.ml(-1) infusion. Measurements of non-invasive blood pressure, heart rate and cardiac output were made in the supine position. The patient was then turned prone onto a Montreal pattern mattress and measurements repeated. Cardiac output measurements were made using a non-invasive cardiac output monitor. We found a significant reduction in cardiac index in both groups and a significantly greater change with propofol compared to isoflurane on turning supine to prone (CI change 0.4 vs 0.7 l.min(-1).m(-2) p = 0.001 and SVRI change 89 vs 177 dyne.s(-1).cm(-5), p = 0.041). We conclude that turning healthy patients prone produces a clinically significant reduction in cardiac output, the change being greater during maintenance of anaesthesia using propofol compared to isoflurane.

Histamine release during adult cardiopulmonary bypass.

Histamine, an inflammatory mediator in its own right, may also be a marker for a more widespread systemic inflammatory process. In this study we have examined variations in plasma histamine concentrations produced during the course of cardiac surgery involving cardiopulmonary bypass, the relationship between these variations and intra-operative events. By assays of serum tryptase and CD-63 expression we have also attempted to identify the source of histamine. Histamine concentrations that were significantly raised from baseline level were demonstrated. These were elevated from the time of aortic cross-clamping and continued to be raised for 24 h postoperatively (p < 0.00625). This was associated with an increase in CD-63 expression (p < 0.025) (but not an increase in tryptase concentration) following aortic cross-clamping and protamine administration, suggesting that basophils are the source of histamine. 41% of patients had arrhythmias in the post bypass period. The rise in histamine levels was not related to the incidence of cardiac arrhythmias.

Flow cytometric investigation of peri-anaesthetic anaphylaxis using CD63 and CD203c.

The investigation of anaphylactic reactions in the peri-operative period is difficult. Elevation of serum tryptase levels is a good indicator of an anaphylactic event but the ability of subsequent investigations to identify the drug(s) responsible for the reaction is still potentially unreliable. The aim of this study was to examine basophil activation as an investigative tool. We performed flow cytometric analysis of the expression on the cell surface of the basophil activation markers CD63 and CD203c and measured histamine release in 21 patients who were referred with possible peri-operative anaphylaxis. The sensitivity of CD63, CD203c, basophil histamine release and skin prick for the muscle relaxants was found to be 79%, 36%, 36% and 64%, respectively; the specificity was found to be 100%. These results demonstrate the difficulty in investigating the cause of an unexpected clinical event following drug administration, but the higher sensitivity of neo-expression on the cell surface of CD63 suggests that flow cytometric analysis of its neo-expression on basophils in vitro may be a diagnostic aid.