Anesthesiology
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Comparative Study
Continuous Fick cardiac output compared to continuous pulmonary artery electromagnetic flow measurement in pigs.
A system for continuous Fick cardiac output measurement (CFCO) is described and compared to continuous electromagnetic pulmonary artery flow (EMCO) and intermittent thermodilution (TDCO) measurements. Oxygen consumption was determined from continuous respiratory gas exchange analysis and arterio-venous oxygen difference from fiberoptic oximetry. A computer calculated cardiac output and other variables every 20 s. ⋯ CFCO is recommended as a reliable standard of continuous cardiac output measurement. It is not a real time measurement; the technique has a time lag of approximately 20 s which is the result of the time constant of the VO2 measurement. Sources for error are discussed with suggestions for improving quality control.
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Randomized Controlled Trial Clinical Trial
The influence of continuous epidural bupivacaine analgesia on the second stage of labor and method of delivery in nulliparous women.
A randomized, double blind, placebo-controlled study was performed to evaluate the analgesic efficacy and influence of continuing an epidural infusion of 0.125% bupivacaine beyond a cervical dilatation of 8 cm in nulliparous women. When the cervix was greater than or equal to 8 cm dilated, coded study solution was substituted for the known 0.125% bupivacaine solution. The study solution for 46 patients was 0.125% bupivacaine; 46 patients received saline. ⋯ Twenty-one of 40 (53%) women in the bupivacaine group, versus 11 of 40 (28%) in the saline group, underwent instrumental vaginal delivery (P less than .05). Twenty-eight of 40 (70%) women in the bupivacaine group, versus six of 40 (15%) in the saline group; had surgical perineal anesthesia for vaginal delivery (P less than .0001). There were no significant differences between groups in Apgar scores or umbilical cord blood acid-base values.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anatomical study of the brachial plexus of 18 cadavers was undertaken to confirm the presence and significance of "septa" dividing the brachial plexus or axillary sheath. Dissection demonstrated that the sheath consists of multiple layers of thin connective tissue surrounding the various elements of the neurovascular bundle. ⋯ Single injections of methylene blue and Latex solutions into the axillary sheath resulted in immediate dye staining of median, radial, and ulnar nerves, despite the presence of septa. These data demonstrate that there are connections between compartments within the sheath and, therefore, do not support the need for multiple injections when performing an axillary block.
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Comparative Study Clinical Trial Controlled Clinical Trial
Epidural hydromorphone: a double-blind comparison with intramuscular hydromorphone for postcesarean section analgesia.