Anesthesiology
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Comparative Study
Manual evaluation of residual curarization using double burst stimulation: a comparison with train-of-four.
Double burst stimulation (DBS) is a new mode of stimulation developed to reveal residual neuromuscular blockade under clinical conditions. The stimulus consists of two short bursts of 50 Hz tetanic stimulation, separated by 750 ms, and the response to the stimulation is two short muscle contractions. Fade in the response results from neuromuscular blockade as with train-of-four stimulation (TOF). ⋯ Fade frequencies were statistically significantly higher with DBS than with TOF, regardless of the TOF ratio level. Absence of fade with TOF implied a 48% chance of considerable residual relaxation as compared with 9% when fade was absent with DBS. The results demonstrate that DBS is more sensitive than TOF in the manual detection of residual neuromuscular blockade.
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To determine the influence of a patient's position on the incidence of dysrhythmias during pulmonary artery catheterization, 34 adult patients scheduled for elective coronary artery bypass graft surgery and pulmonary artery catheterization were studied. All introducers were inserted via the right internal jugular vein using the Seldinger technique with the patient in the Trendelenburg position. For each patient, the pulmonary artery catheter was advanced twice: once while the patient was in the Trendelenburg (T) position with a 5-10 degrees head-down tilt and another with a 5 degrees head-up and right lateral tilt (R) position. ⋯ In 11 of the 13 patients, the dysrhythmia classification changed from malignant in the Trendelenburg position to benign or absent in the right lateral tilt position. Although the incidence of dysrhythmias was similar in both groups, the Trendelenburg position was associated with a significantly higher incidence of malignant dysrhythmias than the right tilt position (P less than 0.05). The authors conclude that the head-up and right lateral tilt position appears superior to the Trendelenburg position for passage of the pulmonary artery catheter in the awake patient scheduled for elective coronary bypass surgery.
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The authors evaluated the efficacy and incidence of side effects from blockade of the femoral nerve with 0.5% bupivacaine in 14 children with fracture of the middle third of the femoral shaft. In nine of these children, a pharmacokinetic analysis was also performed. The onset of analgesia occurred in 8.0 +/- 3.5 minutes after blockade of the femoral nerve. ⋯ The maximum bupivacaine plasma concentration was 0.89 +/- 0.37 microgram/ml, obtained 24.4 +/- 12.6 min after the end of the injection. The femoral nerve blockade with bupivacaine provides prompt, effective, and prolonged analgesia in children suffering from fractures of the femoral shaft, allowing transport, radiographic examination, and application of traction in optimal conditions. Although the sample size was small, the side effects appeared to be rare.
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Isoflurane has been shown to depress skeletal muscle force in vitro, but data are not available regarding the effects of isoflurane on diaphragmatic muscle function in vivo. To answer this question, 15 rats anesthetized with pentobarbital and mechanically ventilated were studied. They were divided into three groups of five animals each, according to the administered concentration of isoflurane. ⋯ No change in Pdi during 50 Hz stimulation was noted during 0.5 and 1 MAC isoflurane exposure, whereas it was reduced at T1 during 1.5 MAC. For 100 Hz stimulation, a significant decrease in Pdi was noted for all groups at T1, which returned toward control values at T2. Edi was markedly reduced for 50 and 100 Hz stimulation, but this reduction was also transient, since Edi returned toward control values at T2.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
The influence of pH-adjusted 2-chloroprocaine on the quality and duration of subsequent epidural bupivacaine analgesia during labor: a randomized, double-blind study.
A randomized, double-blind study was performed to determine whether pH-adjustment of 2-chloroprocaine hastens the onset of epidural analgesia, and improves the quality and duration of subsequent epidural bupivacaine analgesia during labor. One milliliter of either 8.4% sodium bicarbonate or normal saline was added to a 30-ml vial of 2% 2-chloroprocaine. At 0, 5, and 7 min, each patient received 2, 5, and 3 ml of 2-chloroprocaine, respectively. ⋯ Two of 31 women in the bicarbonate group, versus 10 of 31 women in the saline-control group, required an additional 5 ml of 2-chloroprocaine at 22 min to achieve satisfactory analgesia (P = .01). There was no significant difference between groups in median duration of subsequent bupivacaine analgesia (60 min in each group) or mean (+/- SD) dosage of bupivacaine during the first stage of labor (64 +/- 43 versus 72 +/- 57 mg). Also, there was no significant difference between groups in pain scores over time.(ABSTRACT TRUNCATED AT 250 WORDS)