Anesthesiology
-
Randomized Controlled Trial Clinical Trial
Monitoring of heparin-induced anticoagulation with kaolin-activated clotting time in cardiac surgical patients treated with aprotinin.
High-dose aprotinin appears to enhance the anticoagulant effects of heparin, as documented by increases in the activated clotting times (ACTs) during cardiopulmonary bypass; hence, some authorities have advocated reducing the dose of heparin in patients treated with aprotinin. An in vitro study by our group suggested that the increase of the ACT in the presence of aprotinin and heparin may be due to the use of celite as surface activator. We compared celite and kaolin as surface activators for the measurement of the ACT in cardiac surgical patients treated with aprotinin and in patients given no aprotinin. ⋯ The latter also was used for measurement of the blood heparin concentration. The ACTs of blood without heparin did not differ between aprotinin and control patients. During anticoagulation with heparin and cardiopulmonary bypass, the average C-ACTs were 784 +/- 301 s (aprotinin) and 496 +/- 120 s (control) (P < .001); the K-ACTs were 502 +/- 131 s (aprotinin) and 458 +/- 101 s (control) (P > .05); the HR-ACTs were 406 +/- 87 s (aprotinin) and 423 +/- 82 s (control) (P > .05), which was consistently less than C-ACT and K-ACT.(ABSTRACT TRUNCATED AT 250 WORDS)
-
Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of postoperative analgesic effects of intraarticular bupivacaine and morphine following arthroscopic knee surgery.
Recent studies have shown that, in the presence of inflammation, the local administration of opioids results in analgesia. The analgesic efficacy of local anesthetics and morphine administered intraarticularly was compared in patients undergoing arthroscopic knee surgery under epidural anesthesia. We compared postoperative pain scores (VAS) and opioid requirements among 47 patients receiving, in a randomized, double-blinded fashion, one of three intraarticular medications (20 ml): normal saline with 100 micrograms epinephrine (group 1, n = 16); 0.25% bupivacaine with 100 micrograms epinephrine (group 2, n = 15); and 3 mg morphine sulfate and 100 micrograms epinephrine in normal saline (group 3, n = 16). ⋯ Subsequent VAS scores were not significantly different in the three groups. While no patient in group 2 requested analgesics during the first postoperative hour, nine patients in group 3 required systemic analgesics (P < .01). We conclude that no evidence for a peripheral opiate-receptor mediated analgesia could be demonstrated in patients undergoing arthroscopic knee surgery under epidural anesthesia.
-
The interaction in the rat between intrathecal morphine and local anesthetics (bupivacaine and lidocaine) on nociception (52.5 degrees C hot plate and paw pressure), motor function, and autonomic function (blood pressure [BP] and heart rate [HR]) was examined over a range of doses for both morphine and the local anesthetics. High doses of intrathecal bupivacaine (75 micrograms) or lidocaine (500 micrograms) produced motor block and hypotension (150 micrograms bupivacaine) lasting approximately 15 and 7 min, respectively, whereas low doses of intrathecal bupivacaine (25 micrograms) and lidocaine (100 micrograms) produced only a transient motor weakness lasting 2 min or less. Alone, neither agent altered the hot plate or paw pressure response at doses, or at times, where the agents had no effect upon motor function. ⋯ Comparable results were also observed with lidocaine (bupivacaine was found to have no significant effect on spinal cord morphine clearance). We conclude that low doses of intrathecal lidocaine and bupivacaine, which alone have no antinociceptive effect, at times when motor function was clearly unimpaired, are able to significantly augment the antinociceptive activity of intrathecal morphine on the hot plate and paw pressure tests. This prominent and selective potentiation appears to occur via a non-pharmacokinetic mechanism and probably reflects upon the interaction of low concentrations of local anesthetics with systems in the spinal dorsal horn that process acute high threshold afferent input.
-
The proliferation of monitors and alarms in the operating room may lead to increased confusion and misdiagnosis unless the information provided is better organized. Intelligent alarm systems are being developed to organize these alarms, on the assumption that they will shorten the time anesthesiologists need to detect and correct faults. This study compared the human response time (the time between the sounding of an alarm and the resolution of a fault) when anesthesiologists used a conventional alarm system and when they used an intelligent alarm system. ⋯ The standard deviations in response time were only half as large for the intelligent alarm system. It appears that the computer-based neural network in the intelligent alarm system diagnosed faults more rapidly and consistently than did the anesthesiologists. This study indicates that breathing circuit faults may be more rapidly corrected when the anesthesiologist is guided by intelligent alarms.