Forty-five patients were evaluated during knee arthroscopy performed using local anesthesia produced by lidocaine with epinephrine to determine the dose-response relationship for operative analgesia. Serum lidocaine concentrations were also measured. Patients were randomized prospectively to receive 20 mL of 0.5%, 1.0%, or 1.5% lidocaine with epinephrine intraarticularly. Intraoperative discomfort was measured by verbal response on an 11-point linear pain scale. Pain scores were significantly higher in patients receiving 0.5% lidocaine during the first 45 min of surgery (P = 0.03). After 45 min, pain scores continued to be higher in the 0.5% lidocaine group than in the 1.0% or 1.5% groups, but the differences were not statistically significant. Ninety-four percent of patients in the 1.5% lidocaine group were willing to repeat this anesthetic technique for surgery compared with 83% of those in the 1.0% lidocaine group and 75% of those in the 0.5% lidocaine group (P greater than 0.05). The duration of postoperative analgesia was similar in all groups. Serum lidocaine concentrations before and 15, 30, 60, and 120 min after instillation of lidocaine were highest in the 1.5% lidocaine group with a peak concentration of 278 ng/mL. No patient had symptoms of lidocaine toxicity. We recommend that lidocaine concentrations of 1.0% or 1.5% be used when 20 mL is instilled intraarticularly for knee arthroscopy based on patient comfort and absence of lidocaine toxicity.

Eighty-nine patients were studied prospectively to compare the incidence of postdecannulation arterial thrombosis and ischemic complications associated with percutaneous insertion of two different radial artery catheters. Patients scheduled for peripheral vascular surgery were randomized to receive a 15.2-cm (6 in, Argon Medical Corp.) or 4.45-cm (1.75 in, Arrow International, Inc.) 20-gauge, Teflon catheter. Extremity blood flow was evaluated prior to cannulation and again after decannulation with the modified Allen's test, pulse-volume plethysmography, and Doppler ultrasound. The incidence of postdecannulation radial artery occlusion for 15.2-cm catheters was significantly less than for 4.45-cm catheters (4 of 45 cases versus 11 of 44 cases, p = 0.05). No case of temporary or permanent ischemic injury occurred. Radial artery transfixion (16 of 45 cases versus 5 of 44 cases, p = 0.01) and hematoma formation (5 of 45 cases versus 0 of 44 cases, p = 0.02) occurred more frequently during insertion of 15.2-cm catheters than 4.45-cm catheters. The number of arterial punctures during catheter insertion and the duration of cannulation were similar for both groups. Of the 8 patients with positive modified Allen's test who underwent radial artery cannulation, one suffered arterial occlusion. Radial artery cannulation with a 15.2-cm catheter was associated with a lower incidence of postdecannulation radial artery thrombosis than cannulation with the 4.45-cm catheter. Radial artery cannulation with longer catheters (greater than 5.0 cm) appears to be a safe practice.

This second time-study of the anaesthetist's intraoperative period was conducted at The Ohio State University Hospitals. The study involved a total of 30 anaesthetic procedures. The activities of the anaesthetists were videotaped and analysed independently by three reviewers. Unlike our previous study, the present study was performed at a time when automatic noninvasive arterial pressure monitors, automatic ventilators and patient breathing circuit disconnect alarms were in use. The greatest amount of intraoperative time of the anaesthetist (59.1%) was spent monitoring the patient directly (44.8%) or indirectly (14.3%) via patient monitors. This represented an increase from our previous study attributable to the increased use of technology in the operating room. The anaesthetist still spent about 10-12% of his/her time completing patient records.

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