Anesthesia and analgesia
-
Anesthesia and analgesia · Sep 1999
Clinical Trial Controlled Clinical TrialThe preoperative administration of intravenous dextromethorphan reduces postoperative morphine consumption.
We evaluated the effect of dextromethorphan on postoperative pain management. Sixty ASA physical status I-III female patients undergoing major abdominal surgery underwent standardized general anesthesia. Thirty patients received an i.v. infusion of dextromethorphan 5 mg/kg before anesthetic induction (Pre group), whereas the remaining 30 patients received the same volume of isotonic sodium chloride solution, followed by a postoperative i.v. infusion of dextromethorphan 5 mg/kg (Post group). Patients in the Pre group received the same volume of isotonic sodium chloride solution postoperatively. All patients were then treated with patient-controlled i.v. analgesia, which administered a 0.6-mg bolus of morphine on demand (maximal 4 h dose 20 mg). The mean visual analog pain score during cough or movement and at rest were similar in the two groups in the first 3 days postoperatively. However, Post group patients consumed more morphine than Pre group patients during the first 2 days (P < 0.01). The sedation scores, patient satisfaction, and the incidence of morphine-related side effects were similar between the two groups. We conclude that the preoperative administration of dextromethorphan 5 mg/kg reduces postoperative morphine consumption compared with postoperative administration. ⋯ In this double-blinded study, we found that the preoperative administration of i.v. dextromethorphan 5 mg/kg, compared with postoperative administration, reduces postoperative morphine consumption, which may provide clinical evidence of preemptive or preventive analgesic effects of dextromethorphan.
-
Anesthesia and analgesia · Sep 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe effects of antagonizing residual neuromuscular blockade by neostigmine and glycopyrrolate on nausea and vomiting after ambulatory surgery.
The effects of neostigmine on the incidence of postoperative nausea and vomiting (PONV) are controversial. In this study, we evaluated the effects of neostigmine and glycopyrrolate on the incidence of PONV and the need for antiemetics in patients undergoing ambulatory surgery. One hundred healthy patients undergoing outpatient surgical procedures were included in the study. A standardized anesthetic technique was used for all patients. Patients were randomized to receive either mivacurium (n = 50) or rocuronium (n = 50) to achieve muscle paralysis. Bolus doses of mivacurium 2-4 mg or rocuronium 5-10 mg were administered to maintain one or two twitches of the train-of-four stimulation of the ulnar nerve at the wrist. After surgery, residual neuromuscular blockade was reversed with neostigmine 2.5 mg i.v. and glycopyrrolate 0.5 mg i.v. only if clinically deemed necessary (i.e., fade on train-of-four stimulation, inadequate tidal volume, reduced hand grip, or inability to maintain head lift). The incidence of PONV and the need for antiemetics were recorded in the post-anesthesia care unit (PACU), in the phase II unit, and 24 h after surgery. We compared patients who received neostigmine (n = 40) for reversal of residual neuromuscular blockade with those who did not (n = 60). More patients receiving rocuronium required reversal drugs than those receiving mivacurium (68% vs 10%). There were no differences in the incidence of nausea (18% vs 15%), vomiting (8% vs 12%), and the need for antiemetics (13% in both the groups) in the PACU between patients who received neostigmine and those who did not. In addition, the duration of PACU stay and the time to home-readiness were also similar between the groups. We conclude that, compared with rocuronium, the use of mivacurium decreases the need for reversal drugs. In addition, reversal of residual neuromuscular blockade with neostigmine does not increase the incidence of PONV or the need for antiemetic medications in patients undergoing ambulatory surgery. ⋯ In this study, we showed that the incidence of postoperative nausea and vomiting and the need for antiemetics do not increase with the use of neostigmine and glycopyrrolate for reversal of residual muscle paralysis.
-
Anesthesia and analgesia · Sep 1999
Randomized Controlled Trial Clinical TrialFentanyl pretreatment does not impair the reliability of an epinephrine-containing test dose during propofol-nitrous oxide anesthesia.
We designed this study to determine the hemodynamic responses to and the efficacy of a simulated IV test dose during propofol anesthesia based on the conventional heart rate (HR; positive if increase > or =20 bpm), the modified HR (positive if increase > or =10 bpm), and the systolic blood pressure (SBP; positive if increase > or =15 mm Hg) criteria. Eighty healthy patients were randomized to receive 2 mg/kgpropofol or propofol plus fentanyl (100 microg) at the induction of anesthesia (n = 40 each). After endotracheal intubation, anesthesia in both groups was maintained with propofol 8 mg x kg(-1) x h(-1) and 67% nitrous oxide in oxygen. Each group of patients was further divided into a test dose group receiving 1.5% lidocaine 3 mL plus epinephrine 15 microg (1:200,000) or a saline group (n = 20 each) receiving 3 mL of isotonic sodium chloride solution i.v. HR and SBP were monitored for 4 min after the i.v. injection of the study drug. The i.v. injection of the test dose produced a HR increase > or =20 bpm in 20 and 17 patients in the propofol and propofol-fentanyl groups, respectively, whereas all patients receiving the test dose and none receiving saline had HR increases > or =10 bpm. Therefore, in the propofol-fentanyl group, sensitivity, specificity, positive predictive value, and negative predictive value were 85%, 100%, 100%, and 87% according to the conventional HR criterion, and all were 100% according to the modified HR criterion. In the propofol group, 100% efficacy was obtained based on both HR criteria. However, all patients receiving the test dose and none receiving saline developed a SBP increase > or =15 mm Hg, resulting in 100% efficacy based on the conventional SBP criterion in both groups. Our results indicate that both the modified HR criterion and the SBP criterion are clinically applicable during propofol anesthesia with or without supplemental fentanyl. ⋯ To determine whether an epidural catheter is in a blood vessel, an epidural test dose containing 15 microg of epinephrine is used. We found that, during propofol anesthesia with or without fentanyl, a heart rate increase > or =10 bpm and a systolic blood pressure increase > or =15 mm Hg are reliable indicators for detecting accidental intravascular injection.
-
Anesthesia and analgesia · Sep 1999
Clinical TrialUse of abciximab-modified thrombelastography in patients undergoing cardiac surgery.
Thrombelastography (TEG) is a reliable coagulation monitoring system that can guide blood product transfusion in cardiac surgery. The maximum amplitude (MA) of TEG measures clot strength, which is dependent on both fibrinogen level and platelet function. Inhibition of platelet function with abciximab-fab is suggested to permit quantitative assessment of the contribution of fibrinogen to clot strength. We hypothesized that abciximab-modified TEG permits prediction of plasma fibrinogen levels and that the difference of standard MA and abciximab-modified MA (deltaMA) is a correlate for platelet function. We correlated abciximab-modified MA with plasma fibrinogen levels and deltaMA with platelet count in patients undergoing coronary revascularization. Correlation between plasma fibrinogen levels and abciximab-modified MA was significant (adjusted r2: 0.8; P < 0.0001). Correlation of deltaMA with platelet count was not significant when calculated in millimeters (adjusted r2: 0.04; P = 0.73). However, when deltaMA was calculated in dynes per square centimeter (deltaGMA), it correlated significantly with platelet count (adjusted r2: 0.51; P < 0.0001). We conclude that abciximab-modified TEG may therefore help to discriminate between hypofibrinogenemia and platelet dysfunction as a cause of decreased MA. ⋯ We examined the use of abciximab-modified thrombelastography in patients undergoing cardiac surgery. Modification of thrombelastography with abciximab-fab allows prediction of fibrinogen levels, despite coagulation altered by cardiac surgery. The difference of standard maximum amplitude and abciximab-modified maximum amplitude correlates with platelet function when expressed in dynes per square centimeter.
-
Anesthesia and analgesia · Sep 1999
Cardiac output is a determinant of the initial concentrations of propofol after short-infusion administration.
Indicator dilution theory predicts that the first-pass pulmonary and systemic arterial concentrations of a drug will be inversely related to the cardiac output. For high-clearance drugs, these first-pass concentrations may contribute significantly to the measured arterial concentrations, which would therefore also be inversely related to cardiac output. We examined the cardiac output dependence of the initial kinetics of propofol in two separate studies using chronically instrumented sheep in which propofol (100 mg) was infused IV over 2 min. In the first study, steady-state periods of low, medium, and high cardiac output were achieved by altering carbon dioxide tension in six halothane-anesthetized sheep. The initial area under the curve and peak value of the pulmonary artery propofol concentrations were inversely related to cardiac output (R2 = 0.57 and 0.66, respectively). For the systemic arterial concentrations, these R2 values were 0.68 and 0.71, respectively. In our second study, transient reductions in cardiac output were achieved in five conscious sheep by administering a short infusion of metaraminol concurrently with propofol. Cardiac output was lowered by 2.2 L/min, and the area under the curve to 10 min of the arterial concentrations increased to 143% of control. ⋯ The initial arterial concentrations of propofol after IV administration were shown to be inversely related to cardiac output. This implies that cardiac output may be a determinant of the induction of anesthesia with propofol.