Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1991
Randomized Controlled Trial Comparative Study Clinical TrialPlasma inorganic fluoride concentrations during and after prolonged (greater than 24 h) isoflurane sedation: effect on renal function.
We studied the effect of prolonged sedation (greater than 24 h) with isoflurane on plasma inorganic fluoride concentrations and renal function in 60 critically ill patients allocated randomly to receive either isoflurane or midazolam for sedation. In the isoflurane group, plasma fluoride increased from a mean concentration of 3.1 mumol/L to 20.0 mumol/L at the end of sedation, continued to increase to a peak of 25.3 mumol/L 16 h later, and then decreased exponentially (t1/2 = 111 h) to reach normal levels by the fifth day. ⋯ Serum and urinary electrolytes, urine osmolality, and creatinine clearance during and after sedation were similar in the two groups. Isoflurane sedation was associated with an increase in plasma fluoride concentration without any clinical deterioration of renal function.
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Anesthesia and analgesia · Dec 1991
Randomized Controlled Trial Comparative Study Clinical TrialEffects of epidural anesthesia and analgesia on coagulation and outcome after major vascular surgery.
To examine the interaction of epidural anesthesia, coagulation status, and outcome after lower extremity revascularization, 80 patients with atherosclerotic vascular disease were prospectively randomized to receive general anesthesia combined with postoperative epidural analgesia (GEN-EPI) or general anesthesia with on-demand narcotic analgesia (GEN). Demographics did not differ between groups except that the GEN-EPI group had a higher incidence of diabetes mellitus and of previous myocardial infarction. Coagulation status was monitored using thromboelastography. ⋯ The rates of cardiovascular, infectious, and overall postoperative complications, as well as duration of intensive care unit stay, were significantly reduced in the GEN-EPI group. Stepwise logistic regression demonstrated that the only significant predictors of postoperative cardiovascular complications were preoperative congestive heart failure and general anesthesia without epidural analgesia. We conclude that in patients with atherosclerotic vascular disease undergoing arterial reconstructive surgery (a) thromboelastographic evidence of increased platelet-fibrinogen interaction is associated with early postoperative thrombotic events, and (b) epidural anesthesia and analgesia is associated with beneficial effects on coagulation status and postoperative outcome compared with intermittent on-demand opioid analgesia.
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Anesthesia and analgesia · Dec 1991
Valsalva maneuver in obstetrics: the influence of peripheral circulatory changes on function of the pulse oximeter.
Strenuous expulsive efforts involving sequential Valsalva maneuvers may result in maternal hypoxemia during the second stage of labor. Pulse oximetry has been used to assess oxygen saturation in laboring parturients, and this study was undertaken to evaluate the performance of the pulse oximeter (Nellcor) during the Valsalva maneuver. In both pregnant patients and nonpregnant volunteers, there were consistent interruptions in the transmission of oxygen saturation data during the Valsalva maneuver. ⋯ A marked decrease in pulse volume amplitude was noted, which adversely affected the oximeter's ability to distinguish physiologic arterial pulsations from background noise. Each Valsalva maneuver was associated with abrupt and transient changes in peripheral vascular volumes, thus presenting the oximeter with a rapidly changing signal for analysis that violated predetermined software criteria for pulse uniformity and caused an interruption in data transmission. The authors conclude that the Valsalva maneuver interferes with the ability of pulse oximeter technology to provide useful oxygen saturation data.
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Anesthesia and analgesia · Dec 1991
Comparative StudyHypertonic/hyperoncotic fluid resuscitation after hemorrhagic shock in dogs.
We compared canine systemic and cerebral hemodynamics after resuscitation from hemorrhagic shock with 4 mL/kg (a volume approximating 12% of shed blood volume) of 7.2% saline (HS; 1233 mEq/L sodium), 20% hydroxyethyl starch (HES) in 0.8% saline, or a combination fluid consisting of 20% hydroxyethyl starch in 7.2% saline (HS/HES). Eighteen endotracheally intubated mongrel dogs (18-24 kg) were ventilated to maintain normocarbia with 0.5% halothane in nitrous oxide and oxygen (60:40). After a 30-min period of hemorrhagic shock (mean arterial blood pressure = 40 mm Hg), extending from time T0 to T30, animals received one of three randomly assigned intravenous resuscitation fluids: HS, HES, or HS/HES. ⋯ After resuscitation, cerebral blood flow increased, exceeding baseline in the HS and HS/HES groups but remaining low in the HES group (P less than 0.05 HS vs HES at T35). We conclude that small-volume resuscitation (4 mL/kg) with HS, HS/HES, or HES does not effectively restore or sustain systemic hemodynamics in hemorrhaged dogs. In dogs without intracranial pathology, the effects on cerebral hemodynamics are also comparable, except for transiently greater cerebral blood flow in the HS group in comparison with the HES group.
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Anesthesia and analgesia · Dec 1991
Comparative StudyAnesthetic modification of hemodynamic and neuroendocrine stress responses to cesarean delivery in women with severe preeclampsia.
We conducted a prospective evaluation of the comparative effects of lumbar epidural and general anesthesia on the hemodynamic and neuroendocrine stress response to cesarean delivery in 21 women with severe preeclampsia. In the epidural group (n = 11), anesthesia extending to the T-4 dermatome level was obtained using 2% plain lidocaine in divided doses. In the general anesthesia group (n = 10), anesthesia was induced after pretreatment with labetalol or nitroglycerin. ⋯ In the general anesthesia group, both adrenocorticotropic hormone and beta-endorphin-like immunoactivity increased significantly from base levels at skin incision. The catecholamines also increased significantly and remained so throughout the study period. In the epidural group, the concentrations of these hormones decreased or remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)