Anesthesia and analgesia
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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)
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Anesthesia and analgesia · Dec 1991
Comparative StudyTransesophageal Doppler cardiac output monitoring: performance during aortic reconstructive surgery.
Transesophageal Doppler (TED) monitoring provides continuous, noninvasive monitoring of cardiac output by measurement of aortic flow velocities. Because of the effects on aortic flow dynamics resulting from atherosclerosis, aortic cross-clamping, and wide variations in arterial blood pressure, the validity of TED monitoring during aortic surgery is unresolved. The authors prospectively evaluated a second-generation TED cardiac output monitor in 42 patients undergoing aortic reconstructive surgery. ⋯ Placement of an aortic cross-clamp resulted in significant reductions in the accuracy of Doppler measurements. Arterial blood pressure variations did not systematically affect the accuracy of the transesophageal technique. Limitations of TED monitoring, including a difficult calibration procedure, poor performance during aortic cross-clamping, and the need for probe repositioning, suggest further development is warranted.
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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.