Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1994
Does postoperative epidural analgesia increase the risk of peroneal nerve palsy after total knee arthroplasty?
Peroneal nerve palsy is a rare complication of total knee arthroplasty (TKA). Previous studies have investigated surgical variables contributing to the development of peroneal nerve palsy after TKA, but have ignored potential medical and anesthetic risk factors. The charts of all patients undergoing TKA over a 1-yr period were retrospectively studied to identify medical, surgical, and anesthetic risk factors contributing to the development of peroneal nerve palsy after TKA; 361 TKAs were performed on 292 patients. ⋯ However, all cases of peroneal nerve palsy with motor deficits and partial neurologic recovery occurred in patients receiving postoperative epidural analgesia and were diagnosed after discontinuation of the epidural infusion. Since diagnosis of peroneal nerve palsy may be delayed in patients with postoperative epidural analgesia, these patients must be monitored closely. A dilute local anesthetic or an opioid infusion is recommended for patients at increased risk, such as those with preexisting neuropathies.
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Anesthesia and analgesia · Sep 1994
The effects of carrier gas composition on the performance of the Tec 6 desflurane vaporizer.
The new Tec 6 desflurane vaporizer is an electrically heated, pressurized, electromechanically coupled dual-circuit blender. We hypothesized that carrier gas viscosity should affect the electromechanical coupling of the fresh gas and vapor circuits, and that desflurane output should vary with different carrier gases. In the first portion of the study, the performance of eight vaporizers was evaluated using a constant dial setting of 10% desflurane with four different carrier gases and three different fresh gas flow rates. ⋯ At a flow rate of 1.0 L/min with a constant dial setting of 10%, the averaged output from vaporizers was 10.3 +/- 0.66, 9.4 +/- 0.58, 8.7 +/- 0.52, and 8.1 +/- 0.44 vol% for 100% oxygen, air, 30% oxygen plus 70% nitrous oxide, and 100% nitrous oxide, respectively. With 100% nitrous oxide as the carrier gas at a flow rate of 1.0 L/min, the vaporizer delivered 2 vol% less than the dial setting at dial settings in excess of 12%. Differences between the analyzed concentration and the dial setting were most pronounced with high concentrations of nitrous oxide at low fresh gas flow rates.