Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Clinical TrialExperimental pain in healthy human subjects: gender differences in nociception and in response to ibuprofen.
We used electrically induced pain in healthy young subjects to study gender differences in nociception and the analgesic efficacy of ibuprofen. Cutaneous stimulation of the earlobe allowed measurement of pain detection thresholds and maximal pain tolerance. Drug and placebo were each administered twice using a double-blind, randomized, multiple cross-over design. Male subjects had greater stimulus thresholds (lower nociception) compared with female subjects (18 +/- 0.3 vs 15 +/- 0.3 volts, mean +/- SEM; n = 10 in each group) and a greater pain tolerance (24 +/- 0.4 vs 21 +/- 0.4 volts). Response variability was also greater in the male subjects, yet only the men exhibited a statistically significant analgesic response to ibuprofen (deltavolts; ibuprofen versus placebo: 2.80 +/- 0.33 vs -0.18 +/- 0.34; P < 0.05, n = 10). None of these results could be attributed to pharmacokinetic differences. The finding that ibuprofen was less effective in women than in men has potential clinical significance, especially as a factor in the response variability to nonsteroidal antiinflammatory drugs. ⋯ In this study, we examined ibuprofen, a widely used nonsteroidal antiinflammatory drug, for its ability to reduce experimental pain. We found that it had such properties in healthy young male subjects but not in young female subjects. This is a paradox because many of the painful conditions for which nonsteroidal antiinflammatory drugs are used (e.g., rheumatoid arthritis) occur more often in women.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Comparative Study Clinical TrialThe effects of general versus epidural anesthesia for outpatient extracorporeal shock wave lithotripsy.
Although many anesthetic techniques are described for immersion extracorporeal shock wave lithotripsy (ESWL), regional and i.v. techniques are the most commonly reported. This randomized, prospective study compared general anesthesia (GA) and epidural anesthesia (EPID) with regard to effectiveness, side effects, induction time, and recovery in patients undergoing ESWL using an unmodified Dornier HM-3 lithotriptor. Twenty-six healthy outpatients were randomized to GA (propofol, N2O, laryngeal mask airway) or EPID (lidocaine 1.5% with epinephrine). Intraoperative and postoperative supplemental medications, side effects, and complications were noted. Induction times and times required to meet standard recovery criteria were compared between groups. Patients were surveyed regarding their satisfaction with anesthesia. All patients in the EPID group had effective blocks with a single catheter insertion and local anesthetic injection. In the GA group, the LMA was inserted successfully in all patients. Time from room entry to procedure start was significantly less in the GA group (23 +/- 11 vs 34 +/- 9 min; P < 0.05). Patients in the GA group were ready for discharge home earlier (127 +/- 59 vs 178 +/- 49 min; P < 0.05). Only three patients experienced nausea (one in the GA group, two in the EPID group). There were no differences in patient or urologist satisfaction with anesthesia. We conclude that GA is associated with a rapid recovery compared with EPID. ⋯ General anesthesia with propofol, nitrous oxide, and a laryngeal mask airway is comparable to epidural anesthesia with lidocaine for outpatient extracorporeal shock wave lithotripsy procedures. However, early recovery is more rapid after general anesthesia compared with epidural anesthesia.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Clinical TrialThe combination of epinephrine and isoproterenol as a simulated epidural test dose in isoflurane-anesthetized adults.
During isoflurane anesthesia, an epinephrine-containing test dose produces unreliable heart rate (HR) responses with a high incidence of hypertension, whereas an isoproterenol-containing test dose results in a high incidence of hypotension. We designed this study to determine whether different combination doses of epinephrine and isoproterenol produce reliable HR changes without overt fluctuations of systolic blood pressure (SBP). Seventy-five healthy patients were anesthetized with 1% end-tidal isoflurane after endotracheal intubation and randomized to one of five groups (n = 15 each) according to the combination dose given i.v.: epinephrine 15 microg, epinephrine 15 microg + isoproterenol 1.5 microg, epinephrine 7.5 microg + isoproterenol 3 microg, isoproterenol 3 microg, and saline. HR and SBP were measured at 20-s intervals for 4 min after injection. Based on the conventional HR criterion (positive if > or = 20 bpm increase), the epinephrine 15 microg + isoproterenol 1.5 microg, the epinephrine 7.5 microg + isoproterenol 3 microg, and the isoproterenol 3 microg groups yielded 100% sensitivities, specificities, and positive and negative predictive values, whereas all groups yielded 100% efficacy according to the modified HR criterion (positive if > or = 10 bpm increase). Four (27%) and three patients (20%) in the epinephrine 15 microg and the epinephrine 15 microg + isoproterenol 1.5 microg groups, respectively, developed systolic hypertension (SBP > or = 180 mm Hg), whereas four (27%) patients in the isoproterenol 3 microg group developed systolic hypotension (SBP < or = 80% of the preinjection value). We conclude that epinephrine 7.5 microg + isoproterenol 3 microg provides the most reliable HR changes with the least SBP fluctuations. ⋯ To test whether an epidural catheter may be in a blood vessel, various vasoactive drugs are administered during general anesthesia. The authors found that the combination of epinephrine 7.5 microg and isoproterenol 3 microg produced the most reliable heart rate changes with minimal blood pressure fluctuations.
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Anesthesia and analgesia · Jun 1998
Comparative StudyTesting internal consistency and construct validity during evaluation of performance in a patient simulator.
The primary goal of this study was to test the items in a rating system developed to evaluate anesthesiologists' performance in a simulated patient environment. A secondary goal was to determine whether the test scores could discriminate between resident and staff anesthesiologists. Two 5-item clinical scenarios included patient evaluation and induction and maintenance of anesthesia. Rating scales were no response to the problem (score = 0), compensating intervention (score = 1), and corrective treatment (score = 2). Internal consistency was estimated using Cronbach's coefficient alpha. Scores between groups were compared using the Cochran-Mantel-Haenszel test. Subjects consisted of 8 anesthesiology residents and 17 university clinical faculty. The Cronbach's coefficient alpha was 0.27 for Scenario A and 0.28 for Scenario B. Two items in each scenario markedly decreased internal consistency. When these four items were eliminated, Cronbach's coefficient alpha for the remaining six items was 0.66. Faculty anesthesiologists scored higher than residents on all six items (P < 0.001). A patient simulator-based evaluation process with acceptable reliability was developed. ⋯ The reliability of anesthesia clinical performance in a patient simulation environment was assessed in this study. Of 10 items, 4 were poor in the evaluation process. When these items were removed, the reliability of the instrument improved to a level consistent with other studies. Because faculty scored higher than resident anesthesiologists, the instrument also showed discriminant validity.
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Anesthesia and analgesia · Jun 1998
A new and simple maneuver to position the left-sided double-lumen tube without the aid of fiberoptic bronchoscopy.
The double-lumen tube (DLT) is the mainstay of one-lung ventilation (OLV). We sought to determine whether this new intubation maneuver using an endobronchial cuff pressure could be substituted for verification by fiberoptic bronchoscope (FOB) in most conditions requiring left-sided DLT. Seventy-nine patients requiring video-assisted thoracoscopic surgery for pneumothorax or mediastinal mass, or open thoracotomy for lung or esophageal cancer were enrolled in this study. We used 35F (n = 23), 37F (n = 51), or 39F (n = 5) disposable polyvinyl chloride DLTs (Broncho-Cath; Mallinckrodt Medical Ltd., Athlone, Ireland), depending on the height and gender of the patients. The DLTs were inserted deeply until resistance was felt. At that time, the pilot of the endobronchial cuff was connected to the Control-Inflator (VBM Medizintechnik GmbH, Sulz am Neckar, Germany) via a three-way stopcock. The bronchial balloon was inflated with 1.0-2.0 mL of air through the stop-cock until approximately 30 cm H2O of cuff pressure was obtained. The DLT was slowly withdrawn until the pressure of the Control-Inflator decreased to approximately half the peak pressure during the initial phase of removal. At that time, the bronchial balloon was deflated, and the DLT was advanced approximately 1.0 cm (1.5 cm for the 39F DLT); using FOB, its position was checked by an independent observer not involved in positioning the DLTs. The ideal position was defined as that in which the carina was located at the same level with the middle 5 mm between the proximal margin of the endobronchial balloon and the circumferential black mark. In 50 patients the position was ideal, and in 27 patients it was not ideal but was within the margin of the safety. There were only two failures. We conclude that if a FOB is unavailable or inapplicable, this simple and new maneuver may be used as a substitute during the positioning of DLTs. ⋯ The correct position of the double-lumen tube is vital for one-lung ventilation, which has been confirmed with a fiberoptic bronchoscope. We devised a simple maneuver to position the double-lumen tube correctly without a fiberoptic bronchoscope.