Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Clinical TrialThe effect of magnesium sulphate on hemodynamics and its efficacy in attenuating the response to endotracheal intubation in patients with coronary artery disease.
Laryngoscopy and endotracheal intubation may produce adverse hemodynamic effects. Magnesium has direct vasodilating properties on coronary arteries and inhibits catecholamine release, thus attenuating the hemodynamic effects during endotracheal intubation. We studied 36 patients with coronary artery disease (CAD) scheduled for elective coronary artery bypass grafting to evaluate the hemodynamic effects of magnesium and its efficacy in attenuating the response to endotracheal intubation. Patients received either 0.1 mL/kg (50%) magnesium sulfate (50 mg/kg) (Group A, n = 19) or isotonic sodium chloride solution (Group B, n = 17) before the induction of anesthesia and 0.05 mL/kg of isotonic sodium chloride solution (Group A) or lidocaine 2% (1 mg/kg) (Group B) before intubation. The hemodynamic variables were recorded before induction, after the trial drug, after induction, and after endotracheal intubation. Automatic ST segment analysis was performed throughout the study period. Magnesium sulfate administration was associated with increased cardiac index (P < 0.01), a minimal increase in heart rate, and a significant decrease in mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P < 0.001). None of the patients in the magnesium group had significant ST depression compared with three patients in the control group. The magnesium group patients had a significantly lesser increase in MAP (P < 0.05) and SVR (P < 0.01) compared with the control group patients who received lidocaine before endotracheal intubation. Thus, magnesium is an useful adjuvant to attenuate endotracheal intubation response in patients with CAD. ⋯ Endotracheal intubation produces adverse hemodynamic effects, which may be more detrimental in patients with coronary artery disease than in healthy patients. The present study shows that magnesium administered before endotracheal intubation can attenuate this response better than lidocaine.
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Comparative Study Clinical TrialDesflurane and isoflurane produce similar alterations in systemic and pulmonary hemodynamics and arterial oxygenation in patients undergoing one-lung ventilation during thoracotomy.
We tested the hypothesis that desflurane (DES) and isoflurane (ISO) produce similar effects on systemic and pulmonary hemodynamics and arterial oxygenation before, during, and after one-lung ventilation (OLV) in patients undergoing thoracotomy. After obtaining informed consent, anesthesia was induced with sodium thiopental or thiamylal, fentanyl, and vecuronium in 61 ASA physical status II-IV patients. Patients were randomly assigned to receive either DES (n = 30) or ISO (n = 31) in 100% O2 in separate groups. Hemodynamic data (radial and pulmonary artery [PA] catheters) were recorded, and blood gas values were obtained before and after induction; at selected intervals before, during, and after OLV; and before emergence. DES significantly (P < 0.05) increased heart rate (HR) and decreased mean arterial pressure (MAP) and cardiac output (CO). PA pressures and pulmonary vascular resistance (PVR) increased; systemic vascular resistance (SVR) was unchanged. Increases in HR and CO and decreases in MAP and SVR occurred during OLV and DES. Reductions in PaO2 (411 +/- 88 to 271 +/- 131 mm Hg 5 min after beginning OLV; mean +/- SD) and content (CaO2) and increases in shunt fraction (Qs/Qt; 0.25 +/- 0.12 to 0.40 +/- 0.19 at 5 min after beginning OLV) were also observed. ISO increased HR and PA pressures but did not alter MAP, CO, and PVR, in contrast to the findings with DES. Reductions in MAP and SVR and increases in CO and PA pressures were observed during OLV in the presence of ISO. Similar to the findings during DES, decreases in PaO2 and CaO2 and increases in Qs/Qt occurred during OLV and ISO. We conclude that DES and ISO produce very similar alterations in systemic and pulmonary hemodynamics and arterial oxygenation in patients undergoing OLV during thoracotomy. ⋯ Desflurane and isoflurane produce similar cardiovascular and pulmonary effects before, during, and after one-lung ventilation in patients undergoing lung surgery.
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Clinical TrialNeuromuscular effects of rocuronium during sevoflurane, isoflurane, and intravenous anesthesia.
The potency and time course of action of rocuronium were studied in patients anesthetized with 66% nitrous oxide in oxygen and 1.5 minimum alveolar anesthetic concentration of sevoflurane or isoflurane, or a propofol infusion. Potency was estimated by using the single-bolus technique. Neuromuscular block was measured by stimulation of the ulnar nerve and by recording the force of contraction of the adductor pollicis muscle. The mean (95% confidence limits) of the 50% and 95% effective doses were estimated tobe 142 (129-157) and 265 (233-301) microg/ kg, 165 (146-187) and 324 (265-396) microg/kg, and 183 (163-207) and 398 (316-502) microg/kg during sevoflurane, isoflurane, and propofol anesthesia, respectively (P < 0.05 for sevoflurane versus propofol). The mean +/- SD times to onset of maximal block after rocuronium 0.6 mg/kg were 0.96 +/- 0.16, 0.90 +/- 0.16, and 1.02 +/- 0.15 min during sevoflurane, isoflurane, and propofol anesthesia, respectively. The respective times to recovery of the first response in the train-of-four (TOF) stimulation (T1) to 25% and 90% were 45 +/- 13.1 and 83 +/- 29.3 min, 35 +/- 6.1 and 56 +/- 15.9 min, and 35 +/- 9.2 and 55 +/- 19.4 min. The times to recovery of the TOF ratio to 0.8 were 103 +/- 30.7, 69 +/- 20.4, and 62 +/- 21.1 min, and the 25%-75% recovery indices were 26 +/- 11.7, 12 +/- 5.0, and 14 +/- 6.9 min, respectively. There were no differences among groups in the times for onset of action or to recovery of T1 to 25%. However, the times for recovery of T1 to 90%, TOF ratio to 0.8, and recovery index in the sevoflurane group were all significantly longer compared with the other two groups (P < 0.05, < 0.01, and < 0.01, respectively). We conclude that the effects of rocuronium, especially duration of action, are significantly enhanced during sevoflurane compared with isoflurane and propofol anesthesia. ⋯ In routine clinical use, the effects of rocuronium are enhanced by sevoflurane, in comparison with isoflurane and propofol anesthesia, and the recovery is slower. Particular attention should be paid to monitoring of neuromuscular block during sevoflurane anesthesia.
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Comparative Study Clinical TrialSingle-dose tropisetron for preventing postoperative nausea and vomiting after breast surgery.
In this randomized, double-blind, placebo-controlled study, we compared the efficacy of tropisetron 5 mg with tropisetron 2 mg for the prevention of postoperative nausea and vomiting (PONV) after breast surgery. One hundred forty-eight female patients were randomized to receive either tropisetron 5 mg (n = 49), tropisetron 2 mg (n = 49), or saline (n = 50) before the induction of anesthesia with thiopental and morphine. Anesthesia was maintained with nitrous oxide and isoflurane. Postoperative analgesia was provided by patient-controlled analgesia with i.v. morphine. The incidence of PONV, the pain score, and the analgesic requirement were recorded for 48 h. There was no difference among groups in patient characteristics, risk factors for PONV, morphine consumption, or side effects. During the first 6 h postoperatively, the incidence of PONV after tropisetron 2 mg and 5 mg were similar and were superior to placebo (P < 0.001). After 6 h, the incidence of PONV increased significantly in patients who had received tropisetron 2 mg (P = 0.01) and was greater than that in patients who had received tropisetron 5 mg (P = 0.001). We conclude that single-dose tropisetron 5 mg is more effective than tropisetron 2 mg in the prevention of PONV after breast surgery. ⋯ Breast surgery is associated with a high incidence of postoperative nausea and vomiting. A single dose of i.v. tropisetron 5 mg is well tolerated and decreases the number of vomiting and nausea episodes after surgery.
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Anesthesia and analgesia · Oct 1998
A survey on the intended purposes and perceived utility of preoperative cardiology consultations.
Cardiology consultations are often requested by surgeons and anesthesiologists for patients with cardiovascular disease. There can be confusion, however, regarding both the reasons for a consultation and their effect on patient management. This study was designed to determine the attitudes of physicians toward preoperative cardiology consultations and to assess the effect of such consultations on perioperative management. A multiple-choice survey regarding the purposes and utility of cardiology consultations was sent to randomly selected New York metropolitan area anesthesiologists, surgeons, and cardiologists. In addition, the charts of 55 consecutive patients aged >50 yr who received preoperative cardiology consultations were examined to determine the stated purpose of the consult, recommendations made, and concordance by surgeons and anesthesiologists with cardiologists' recommendations. Of the 400 surveys sent to each specialty, 192 were returned from anesthesiologists, 113 were returned from surgeons, and 129 were returned from cardiologists. There was substantial disagreement on the importance and purposes of a cardiology consult: intraoperative monitoring, "clearing the patient for surgery," and advising as to the safest type of anesthesia were regarded as important by most cardiologists and surgeons but as unimportant by anesthesiologists (all P < 0.05). Most surgeons (80.2%) felt obligated to follow a cardiologist's recommendations, whereas few anesthesiologists (16.6%) felt so obligated (P < 0.05). The most commonly stated purpose of the 55 cardiology consultations examined was "preoperative evaluation." Only 5 of these (9%) were obtained for patients in whom there was a new finding. Of the cardiology consultations, 40% contained no recommendations other than "proceed with case," "cleared for surgery," or "continue current medications." Recommendations regarding intraoperative monitoring or cardiac medications were largely ignored. ⋯ We conclude that there seems to be considerable disagreement among anesthesiologists, cardiologists, and surgeons as to the purposes and utility of cardiology consultations. A review of 55 consecutive cardiology consultations suggests that most of them give little advice that truly affects management.