Anaesthesia
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Standard cardiorespiratory monitoring may fail to detect occult tissue ischaemia. This study assessed whether a near infra-red spectroscopy tissue oxygen saturation monitor (InSpectra™) could detect progressive peripheral tissue ischaemia and whether hyperoxia may confound tissue oxygen saturation measurement. ⋯ The rate and magnitude of decreases in tissue oxygen saturations were greater during high- than low-pressure ischaemia with a mean (SD) desaturation rate of 3.3 (0.9) vs 1.8 (0.8) %.min(-1) (p<0.01). The dose-related association and lack of confounding by hyperoxia suggest that tissue oxygen saturation monitoring may be a useful adjunct to detect occult ischaemia.
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We examined the pre-emptive analgesic effect of a cyclooxygenase (COX)-2 inhibitor in a rat surgical pain model and characterised the changes in cutaneous COX-2 around a surgical site. Thermal hyperalgesia and mechanical allodynia were tested in the rats for three days after incision and skin tissues were collected for analysis of COX-2. There was decreased expression of cutaneous COX-2 one day after surgical incision. Pre-incision injection of the COX-2 inhibitor significantly inhibited expression of COX-2 and also reduced thermal hyperalgesia (but not mechanical allodynia) compared with the post-incision COX-2-inhibitor injection group, one day after incision.