Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2006
Randomized Controlled Trial Comparative StudyThe effect of sevoflurane on cerebral autoregulation in young children as assessed by the transient hyperemic response.
The transient hyperemic response (THR) test is a simple, noninvasive technique to evaluate cerebral autoregulation using transcranial Doppler. It has not yet been used in studies involving children. In this study we evaluated this response in children undergoing general anesthesia using sevoflurane. ⋯ A THRR of more than 1.09 has previously been accepted as the lower limit of a positive response. The results in this study suggest that THR is affected by sevoflurane in a dose-dependent fashion but is maintained at up to 1.5 MAC. This suggests cerebral autoregulation is preserved in children anesthetized with up to 1.5 MAC sevoflurane.
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Anesthesia and analgesia · Apr 2006
Comparative StudyFibrinogen concentrate reverses dilutional coagulopathy induced in vitro by saline but not by hydroxyethyl starch 6%.
Severe bleeding often induces coagulopathy via loss, consumption, and dilution of clotting factors and platelets. The aims of our in vitro study were to characterize the influence of progressive hemodilution with either NaCl 0.9% or hydroxyethyl starch (HES) 6% on blood clot formation and to analyze the effect of substitution of fibrinogen and platelets on dilutional coagulopathy. Whole blood samples drawn from 8 volunteers were diluted from 20% to 80% of the sample volume with both diluents separately. ⋯ Platelets alone or in addition were not able to improve clot firmness to a clinically relevant extent. Dilutional coagulopathy induced by crystalloids can, in vitro, be effectively reversed by supplementation of fibrinogen. In contrast, HES molecules interfere with fibrin polymerization and, thus, administration of fibrinogen after dilution with HES 6% failed to significantly improve clot firmness.
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Anesthesia and analgesia · Apr 2006
Comparative StudyPostoperative delirium: the importance of pain and pain management.
Postoperative delirium is common in geriatric patients. Few studies have examined events in the postoperative period that may contribute to the occurrence of postoperative delirium. We hypothesized that postoperative delirium is related to postoperative pain and/or pain management strategy. ⋯ By multivariate logistic regression, age (odds ratio [OR], 2.5; 95% confidence interval [CI] 1.5 to 4.2), moderate (OR, 2.2; 95% CI 1.2 to 4.0) and severe (OR, 3.7; 95% CI 1.5 to 9.0) preoperative resting pain, and increase in level of pain from baseline to postoperative day one (OR, 1.1; 95% CI 1.01 to 1.2) were independently associated with a greater risk for the development of postoperative delirium. In contrast, patients who used oral opioid analgesics as their sole means of postoperative pain control were at decreased risk of developing delirium in comparison with those who used opioid analgesics via IV patient-controlled analgesia technique (OR, 0.4; 95% CI 0.2 to 0.7). These results validate our hypothesis that pain and pain management strategies are important factors related to the development of postoperative delirium in elderly patients.
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Anesthesia and analgesia · Apr 2006
Comparative StudyA-line, bispectral index, and estimated effect-site concentrations: a prediction of clinical end-points of anesthesia.
Autoregressive modeling with exogenous input of middle-latency auditory evoked potentials (A-Line AEP index, AAI) has been developed for monitoring depth of anesthesia. We investigated the prediction of recovery and dose-response relationship of desflurane and AAI or bispectral index (BIS) values. Twenty adult men scheduled for radical prostatectomy were recruited. ⋯ The opening of eyes was best predicted by the calculated desflurane effect-site concentration. The relationship between predicted desflurane effect-site concentration versus AAI and BIS was calculated by nonlinear regression analysis (r = 0.75 for AAI and r = 0.80 for BIS). The correlation between BIS and clinical end-points of anesthesia or the desflurane effect-compartment concentration is better than for the AAI.
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Anesthesia and analgesia · Apr 2006
Comparative StudySkin temperature during regional anesthesia of the lower extremity.
Increase in skin temperature (Ts) occurs early during neuraxial blocks. However, the reliability of Ts to predict successful peripheral block is unknown. Therefore, we investigated whether an increase in Ts more than 1 degrees C precedes or follows an impairment of sensation after combined femoral and sciatic nerve block as well as after epidural anesthesia. ⋯ We conclude that an increase of Ts is a reliable, but late, sign of successful sciatic nerve block. Therefore it is of limited clinical value. Ts changes after femoral nerve block are negligible and late.