Anesthesia and analgesia
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe assessment of four different methods to verify tracheal tube placement in the critical care setting.
One of the most serious complications of conventional endotracheal intubation is unidentified placement of the tube in the esophagus. The aim of our study was to evaluate four different methods for immediate detection of the tube position: auscultation, capnographic determination of ETCO2, esophageal detection method (EDM) using a self-inflating bulb, and the transillumination method using a lighted stylet (Trachlight; Laerdal, Armonk, NY). Thirty-eight endotracheally intubated patients admitted to our medical intensive care unit were enrolled in the study. A second identical tube was inserted into the esophagus under laryngoscopic control. The endotracheal tube was then disconnected from the ventilator. Two blinded examiners, one experienced, the other inexperienced, determined the tube position within 30 s using one of the four methods. The order of the tubes tested and the methods used were randomized. In 130 of 152 examinations, both examiners correctly diagnosed the position of the tube. The wrong result was obtained by both examiners 4 times; only the experienced examiner was wrong 4 times, and only the inexperienced examiner was wrong 14 times. Using ETCO2, both examiners were correct in all cases. Auscultation showed an obvious relation to the examiner's experience: the experienced examiner was correct in all cases, the inexperienced examiner was correct in only 68% of cases. Using the self-inflating bulb, there were two wrong results of the experienced examiner and one wrong result of the inexperienced examiner. The transillumination technique was associated with a high error rate by both examiners (16% and 13%, respectively). Comparing all four methods showed that capnography is superior to auscultation (P = 0.0005) and to the Trachlight detection method (P = 0.0078). EDM was not statistically superior to auscultation and transillumination. Capnography was the most reliable method for rapid evaluation of tube position, followed by EDM, whereas auscultation and Trachlight did not seem to be of comparable value. Experience was a determining factor for auscultation. ⋯ To prevent unidentified esophageal intubation, a serious complication in the critical care setting, four methods for detecting tube position were tested by two examiners (one experienced, the other inexperienced) in endotracheally intubated patients after insertion of a second tube into the esophagus.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialLess core hypothermia when anesthesia is induced with inhaled sevoflurane than with intravenous propofol.
Hypothermia after the induction of anesthesia results initially from core-to-peripheral redistribution of body heat. Sevoflurane and propofol both inhibit central thermoregulatory control, thus causing vasodilation. Propofol differs from sevoflurane in producing substantial peripheral vasodilation. This vasodilation is likely to facilitate core-to-peripheral redistribution of heat. Once heat is dissipated from the core, it cannot be recovered. We therefore tested the hypothesis that the induction of anesthesia with i.v. propofol causes more core hypothermia than induction with inhaled sevoflurane. We studied patients undergoing minor oral surgery randomly assigned to anesthetic induction with either 2.5 mg/kg propofol (n = 10) or inhalation of 5% sevoflurane (n = 10). Anesthesia in both groups was subsequently maintained with sevoflurane and 60% nitrous oxide in oxygen. Calf minus toe skin temperature gradients <0 degrees C were considered indicative of significant vasodilation. Ambient temperature and end-tidal concentrations of maintenance sevoflurane were comparable in each group. Patients in both groups were vasodilated throughout most of the surgery. Nonetheless, core temperatures in patients who received propofol were significantly lower than those in patients who received inhaled sevoflurane. These data support our hypothesis that even a brief period of vasodilation causes substantial redistribution hypothermia that persists throughout surgery. ⋯ Core temperatures in patients who received i.v. propofol were consistently lower than those in patients who received inhaled sevoflurane, although anesthesia was subsequently maintained with sevoflurane in nitrous oxide in both groups. This suggests that even a brief period of propofol-induced vasodilation during anesthetic induction causes substantial redistribution hypothermia that persists throughout surgery.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Clinical TrialOptimization of the dose of intrathecal morphine in total hip surgery: a dose-finding study.
We designed this study to determine the optimal intrathecal dose of morphine in total hip surgery. The optimal intrathecal dose was defined as that providing effective analgesia and minimal side effects 24 h after total hip surgery. Patients (n = 143) scheduled for total hip surgery were randomized to four double-blinded groups with a standardized bupivacaine dose but different doses of intrathecal morphine (Group I = 0.025 mg, Group II = 0.05 mg, Group III = 0.1 mg, and Group IV = 0.2 mg). Pain scores, i.v. morphine intake (patient-controlled analgesia), and morphine-related side effects (respiratory depression, postoperative nausea and vomiting, itching, urinary retention) were recorded for 24 h after surgery. Excellent postoperative pain relief was present in all groups. The highest pain scores were found in Group I. The mean use of systemic morphine administered by patient-controlled analgesia infusion pump was 23.7, 17.8, 10.9, and 9.9 mg in Groups I-IV, respectively (P < 0.01 for Groups III and IV versus Group I). We conclude that 0.1 mg of intrathecal morphine is the optimal dose for pain relief after hip surgery with minimal side effects. ⋯ Earlier studies showed excellent postoperative pain relief after intrathecal morphine. However, the severity of side effects resulted in decreased enthusiasm for this anesthesia technique. In the present study, we show that an intrathecal dose of 0.1 mg of morphine can be used safely in total hip surgery with excellent postoperative pain relief.