Journal of cardiothoracic and vascular anesthesia
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J. Cardiothorac. Vasc. Anesth. · Feb 1993
Randomized Controlled Trial Clinical TrialClonidine premedication for coronary artery bypass grafting under high-dose alfentanil anesthesia: intraoperative and postoperative hemodynamic study.
The purpose of this study was to assess the efficacy of clonidine in achieving perioperative hemodynamic stability in patients undergoing coronary artery bypass grafting performed under high-dose alfentanil anesthesia. Twenty-four patients with left ventricular ejection fraction greater than 0.5 were prospectively studied in a double-blind manner; those requiring emergency procedures were excluded. They were randomized to receive either oral clonidine or placebo together with their premedication. ⋯ The postbypass hemodynamic profiles were similar. Severe hemodynamic impairment occurred in the clonidine group during warming in the postoperative period: this group showed a drop in systemic vascular resistance index (1276 +/- 347 v 1757 +/- 415 dyn.sec.cm-5.m2) that could not be compensated for by an increase in cardiac output despite normal filling pressures, causing hypotension (66 +/- 10 v 79 +/- 16 mmHg). This hemodynamic status led to greater requirements for vasoactive agents and inotropics in this group.(ABSTRACT TRUNCATED AT 250 WORDS)
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J. Cardiothorac. Vasc. Anesth. · Feb 1993
Comparative StudyAccuracy of pulse oximetry in children with cyanotic congenital heart disease.
The use of a pulse oximeter to monitor arterial oxygen saturation (SaO2) is considered accurate and reliable in the range of 90% to 100%. However, differing reports exist about the accuracy with desaturation. Thus, the suitability of pulse oximetry in desaturated patients was evaluated using a Nellcor N-100 oximeter. ⋯ Bias and precision between saturations measured by the pulse oximeter and the CO-oximeter were 5.8 and 4.8 in the group with a saturation below 80%, and 0.5 and 2.5 in the group with a saturation over 90%, respectively. Because the margin of safety for a patient is small when arterial saturation levels are under 80%, it is advisable under this condition to check the SaO2 measurements by a CO-oximeter. High hematocrit levels did not seem to be responsible for impaired accuracy of pulse oximetry at saturation values below 80%.
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J. Cardiothorac. Vasc. Anesth. · Feb 1993
Comparative StudyComparison of the pharmacokinetics of methohexital during cardiac surgery with cardiopulmonary bypass and vascular surgery.
The aim of this study was to assess the pharmacokinetics of methohexital (ME) in major vascular surgery (VASC) and to compare these data with the pharmacokinetics of ME during hypothermic cardiopulmonary bypass (HCPB) (temperature: 28 degrees C) and normothermic cardiopulmonary bypass (NCPB) (temperature: 37 degrees C). An ME bolus (2 mg/kg) was administered to 8 VASC patients at the start of surgery and to 11 HCPB patients and 11 NCPB patients at the start of cardiopulmonary bypass (CPB). Twenty-one arterial blood samples were withdrawn over the following 24 hours for ME assays. ⋯ It is concluded that ME clearance is lower in patients undergoing major vascular surgery than in healthy patients. The temperature and the duration of CPB do not seem to substantially influence the pharmacokinetics of ME when a bolus is administered. Parameters such as AUC, TBC, and VD appear modified by hemodilution during CPB; however, T1/2 and MRT, which allow comparisons between CPB and non-CPB patients, were similar in these patients.
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J. Cardiothorac. Vasc. Anesth. · Feb 1993
Effects of dexmedetomidine on systemic and coronary hemodynamics in the anesthetized dog.
In addition to central effects, which are the basis of their use in anesthesiology, alpha 2-adrenergic agonists have direct peripheral cardiovascular effects. Dexmedetomidine (DM) has been found to depress cardiac function in dogs, even after autonomic denervation. The present experiments evaluated the effects of DM on coronary flow, myocardial oxygen extraction, and cardiac function in intact, open chest dogs under enflurane anesthesia. ⋯ DM caused immediate dose-dependent increases in SVRI, CVR, LVEDP, C(a-v)O2, and C(a-cs)O2, and decreases in HR, and CI, with recovery between doses. DP/dtmax declined after the first two doses and stabilized thereafter, as plasma CA fell to minimal levels. Atipamezole completely reversed all changes.(ABSTRACT TRUNCATED AT 250 WORDS)
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J. Cardiothorac. Vasc. Anesth. · Feb 1993
Perioperative measurements of interleukin-6 and alpha-melanocyte-stimulating hormone in cardiac transplant patients.
Interleukin-6 (IL-6) and alpha-melanocyte-stimulating hormone (alpha MSH) are important modulators of the immunologic response to tissue injury and antigenic challenge. Serial changes in the plasma concentrations of these two peptides were measured in 12 patients undergoing heart transplantation. Tissue concentrations of IL-6 in atrial samples from both donor and recipient hearts were also compared. ⋯ These combined results suggest that CPB causes a marked increase in IL-6, and that implantation of a new heart in transplant patients does not augment this increase. The return of IL-6 to control values by 24 hours in the patients who have had transplants suggests that immunosuppression has an appreciable effect on IL-6 at this time. In contrast to IL-6, plasma alpha MSH never increased above control values.(ABSTRACT TRUNCATED AT 250 WORDS)