Anesthesiology
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Randomized Controlled Trial Clinical Trial
Preemptive analgesia: intraperitoneal local anesthetic in laparoscopic cholecystectomy. A randomized, double-blind, placebo-controlled study.
A controversy exists over the effectiveness and clinical value of preemptive analgesia. Additional studies are needed to define the optimum intensity, duration, and timing of analgesia relative to incision and surgery. ⋯ The results indicate that intraperitoneal local anesthetic blockade administered before or after surgery preempts postoperative pain relative to an untreated placebo-control condition. However, the timing of administration is also important in that postoperative pain intensity and analgesic consumption are both lower among patients treated with local anesthetic before versus after surgery.
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Anesthesia produces atelectasis in the dependent areas of the lungs by mechanisms that remain unknown. It has been proposed that anesthesia produces a cephalad shift in the end-expiratory position of the diaphragm, which compresses the lungs and produces atelectasis. This study tested the hypothesis that the extent of atelectasis is correlated with the cephalad displacement of the dependent portion of the diaphragm produced by halothane anesthesia in healthy young human subjects. ⋯ The dependent lung atelectasis produced by halothane anesthesia does not appear to be related to changes in the position of any single chest wall structure in these healthy young subjects, but rather to an interaction of several factors that remain to be identified.
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Cannulation of the internal jugular vein (IJV) is associated with a 95% success rate when external landmarks are used. Anatomic variability has been implicated as the cause for difficulty in cannulation without ultrasound. In contrast to an IJV located lateral to the carotid artery (CA), an IJV overlying the CA may result in CA puncture. The authors' purpose in this study was to examine, using ultrasound, the anatomic relation of the IJV and CA as viewed from the perspective of a cannulating needle. ⋯ In a majority of patients, the IJV is not lateral to the CA in an ultrasound imaging plane positioned in the direction of a cannulating needle. Instead, the IJV overlies the CA in 54% of patients overall, predisposing these patients to CA puncture if the cannulating needle traverses the IJV.
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Cervical spine kinetics during airway manipulation are poorly understood. This study was undertaken to quantify the extent and distribution of segmental cervical motion produced by direct laryngoscopy and orotracheal intubation in human subjects without cervical abnormality. ⋯ This investigation quantifies the behavior of the normal cervical spine during direct laryngoscopy with a Macintosh blade. With this maneuver, the vast majority of cervical motion is produced at the occipitoatlantal and atlantoaxial joints. The subaxial cervical segments (C2-C5) are displaced only minimally. This study establishes a highly reliable and reproducible method for analyzing cervical motion in real time.
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This investigation examined the effects of desflurane and sevoflurane on quantitative indices of left ventricular afterload derived from aortic input impedance (Zin) interpreted using a three-element Windkessel model. ⋯ The results indicate that desflurane and sevoflurane produce substantially different effects on left ventricular afterload in chronically instrumented dogs. Desflurane-induced decreases in systemic vascular resistance occur primarily because of effects on arteriolar resistance vessels. In contrast, sevoflurane increased C and Zc concomitant with pressure-dependent reductions in aortic diameter, suggesting that this anesthetic may alter left ventricular afterload by affecting the mechanical properties of the aorta.