Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialThe incidence of right upper-lobe collapse when comparing a right-sided double-lumen tube versus a modified left double-lumen tube for left-sided thoracic surgery.
Lung deflation for left-sided thoracic surgery can be accomplished by using either a left- or right-sided double-lumen endotracheal tube (L-DLT or R-DLT). Anatomic variability of the right mainstem bronchus and the possibility of right upper-lobe obstruction have discouraged the routine use of R-DLT. There are, however, situations in which it is preferable to avoid manipulation/intubation of the left main bronchus, requiring placement of a R-DLT. We compared the modified L-DLT with the R-DLT to determine whether R-DLTs can be used during left-sided thoracic surgery without an increased risk of right upper-lobe collapse. Forty patients requiring left lung deflation were randomly assigned to one of two groups. Twenty patients received a modified L-DLT BronchoCath((R)) (Mallinckrodt Medical Inc., St. Louis, MO), and 20 received a R-DLT BronchoCath((R)). The following variables were studied: 1) time required to position each tube until satisfactory placement was achieved; 2) number of times fiberoptic bronchoscopy was required to readjust tube position; 3) number of malpositions after initial tube placement; 4) time required for left lung collapse; 5) incidence of right upper-lobe collapse from an intraoperative chest radiograph obtained in a lateral decubitus position; 6) overall surgical exposure; and 7) tube acquisition cost. Median time required for initial tube placement was greater in the R-DLT group (3.4 min) versus the L-DLT (2.1 min); P = 0.04. Overall tube cost was also larger for the R-DLT group (US $1819.40) versus the L-DLT group (US $1107.75). The incidence of malpositions, (five versus two), need for fiberoptic bronchoscopy, time for adequacy of left lung collapse, and incidence of intraoperative right upper-lobe collapse (0) did not significantly differ between R-DLT and L-DLT groups. We conclude that R-DLTs can be used for left-sided thoracic surgery without an increased risk of right upper-lobe collapse. Our data suggest that R-DLTs may be more prone to intraoperative dislodgment/malposition than L-DLTs; however, in all cases, correction of malposition was easily achieved. ⋯ In this study, right-sided double-lumen tubes (R-DLTs) were compared with modified left-sided double-lumen tubes in patients requiring one-lung ventilation for left-sided thoracic surgery. The incidence of right upper-lobe collapse was assessed intraoperatively by a chest radiograph which showed no collapse of the right upper lobe in all patients who received R-DLTs or left-sided double-lumen tubes. Therefore, we conclude that R-DLTs present no increased risk of complications for left-sided thoracic surgery and should not be abandoned.
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Anesthesia and analgesia · Mar 2000
Spinal nerve function in five volunteers experiencing transient neurologic symptoms after lidocaine subarachnoid anesthesia.
The etiology of transient neurologic symptoms (TNS) after 5% lidocaine spinal anesthesia remains undetermined. Previous case reports have shown that patients acutely experiencing TNS have no abnormalities on neurologic examination or magnetic resonance imaging. The aim of our study was to determine whether volunteers with TNS would exhibit abnormalities in spinal nerve electrophysiology. Twelve volunteers with no history of back pain or neurologic disease underwent baseline electromyography (EMG), nerve conduction studies, and somatosensory-evoked potential (SSEP) testing. Then, the volunteers were administered 50 mg of 5% hyperbaric lidocaine spinal anesthesia and were placed in a low lithotomy position (legs on four pillows). The next day, all volunteers underwent follow-up EMG, nerve conduction, and SSEP testing and were questioned and examined for the presence of complications including TNS (defined as pain or dysthesia in one or both buttocks or legs occurring within 24 h of spinal anesthesia). Volunteers who had TNS underwent additional EMG testing 4-6 wk later. Five of the 12 volunteers reported TNS. No volunteer had an abnormal EMG, nerve conduction study, or SSEP at 24 h follow up, nor were there any changes in EMG studies at delayed testing in the five volunteers experiencing TNS. On statistical analysis, the right peroneal and the right tibial nerve differed significantly for all volunteers from pre- to postspinal testing. When comparing pre- and postspinal testing of the TNS and non-TNS volunteers, statistically significant changes occurred in the nerve conduction tests of the right peroneal and left tibial nerve. There was no difference in measurements of F response, H reflex latency, amplitude, or velocity for either leg. Multivariate analysis of variance showed no significant difference between TNS and non-TNS volunteers for the changes in the nine nerve conduction tests when considered together (P = 0.4). We conclude that acute TNS after lidocaine spinal anesthesia did not result in consistent abnormalities detectable by EMG, nerve conduction studies, or SSEP in five volunteers. ⋯ Electrophysiologic testing in volunteers experiencing transient neurologic symptoms is not abnormal.
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Anesthesia and analgesia · Mar 2000
Age-related thermoregulatory differences in a warm operating room environment (approximately 26 degrees C).
Inadvertent hypothermia occurs frequently at typical ambient operating room (OR) temperatures, especially in elderly patients receiving general anesthesia. The aims of the current study were to 1) determine the incidence and magnitude of core hypothermia in an unusually warm OR environment, and 2) to assess age-related differences in perioperative thermoregulatory responses under these circumstances. Forty patients receiving general anesthesia for orthopedic surgical procedures (20 younger patients, 20-40 yr old) and (20 older patients, 60-75 yr old) were enrolled. Mean ambient temperature in the ORs was 25.8 degrees +/- 0.2 degrees C. Core temperature, vasoconstriction, and shivering were compared in the younger and older age groups. Mean core temperature on admission to the postanesthesia care unit was not significantly different in the younger (36.7 degrees +/- 0.1 degrees C) and older (36.4 degrees +/- 0.1 degrees C) age groups. Only 10% of patients (n = 4, 1 younger, 3 older) were admitted with a core temperature <36.0 degrees C. Only 2% of patients (n = 1, older group) had a core temperature <35.5 degrees C. This very mild degree of hypothermia was associated with postoperative vasoconstriction in 80% of the younger and 55% of the older patients (P = 0.18). Postoperative shivering occurred in 40% of the younger patients and in 10% of the older patients (P = 0.06). In summary, an ambient OR temperature near 26 degrees C (79 degrees F) is effective in preventing core hypothermia during general anesthesia regardless of patient age. Even very mild postoperative hypothermia may initiate thermoregulatory responses. ⋯ By increasing ambient temperature in the operating room to 26 degrees C (79 degrees F), the incidence of core hypothermia can be dramatically reduced in both younger and older patients.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of rabeprazole, lansoprazole, and ranitidine for improving preoperative gastric fluid property in adults undergoing elective surgery.
Acid aspiration syndrome at the induction of anesthesia is still a potentially life-threatening complication. Its severity is affected by both pH and volume of the gastric juice that is aspirated. We compared the effects of rabeprazole (a new proton pump inhibitor), lansoprazole, and ranitidine on gastric fluid properties in a prospective, randomized, double-blinded fashion in 180 adult patients undergoing elective surgery. Patients were divided into six groups (n = 30 in each) according to their premedication. Patients in each group received placebo-rabeprazole (PLA-RAB), rabeprazole-placebo (RAB-PLA), rabeprazole-rabeprazole (RAB-RAB), lansoprazole-lansoprazole (LAN-LAN), placebo-ranitidine (PLA-RAN), or placebo-placebo (PLA-PLA) for the first-second medication. Each dose of the study drug was 20 mg for rabeprazole, 30 mg for lansoprazole, and 150 mg for ranitidine. The first medication was given orally at 9:00 PM on the day before surgery and the second at 5:30 AM on the day of surgery. Each patient fasted overnight and took the drug with 20 mL of water. After tracheal intubation, gastric fluid was aspirated via an orogastric tube, and the volume and pH of the aspirate was measured. Preoperative gastric fluid acidity and volume were improved by the study drugs in the following order: PLA-RAN (pH 5.3, volume 0.10 mL/kg), RAB-RAB, LAN-LAN, PLA-RAB, and RAB-PLA (pH 3.8, volume 0.22 mL/kg). The proportion of patients at risk of acid aspiration syndrome according to the traditional criteria (pH < 2.5 and volume > 0.4 mL/kg) was minimized in Groups RAB-RAB and PLA-RAN (0%). We concluded that a single morning dose of ranitidine rather than two doses (bedtime and morning) of rabeprazole was the most effective premedicant to control gastric fluid properties and to minimize the risk of aspiration pneumonitis. ⋯ Acid aspiration syndrome at the induction of anesthesia is rare but still a potentially life-threatening complication. We compared rabeprazole, lansoprazole, and ranitidine for reduction of preoperative gastric fluid acidity and volume in elective surgery and found that a combination of bedtime and morning doses of rabeprazole, or a morning dose of ranitidine, similarly minimized the variables. In adult patients who are at risk of aspirating gastric contents, improvement of gastric fluid environment by rabeprazole can reasonably be anticipated to provide protection against pneumonitis should regurgitation and aspiration of gastric contents occur.