Journal of cardiothoracic and vascular anesthesia
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J. Cardiothorac. Vasc. Anesth. · Apr 1991
Blood/gas solubility coefficient and blood concentration of enflurane during normothermic and hypothermic cardiopulmonary bypass.
The blood/gas solubility coefficient and blood concentration of enflurane were measured at intervals in 10 patients undergoing coronary artery revascularization with cardiopulmonary bypass (CPB) and moderate hypothermia. A constant end-tidal concentration of enflurane was maintained throughout the study. Blood/gas solubility coefficient was determined at 37 degrees C, which when combined with an initial single-step equilibration of the blood sample with air, permitted the accurate measurement of blood concentration. ⋯ On rewarming, blood concentration levels rapidly returned to levels similar to those measured before cooling. The increased uptake and accumulation of volatile anesthetic agent that occurred as a result of the period of hypothermic CPB was rapidly cleared. The rapidity with which blood concentration responded to the changes occurring during CPB make it unlikely that there was any significant increase in myocardial depression in response to the raised blood concentration secondary to the hypothermia.
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J. Cardiothorac. Vasc. Anesth. · Apr 1991
High-dose alfentanil for myocardial revascularization: a hemodynamic and pharmacokinetic study.
It has been suggested that high plasma levels of alfentanil are required in order to control hemodynamic responses to noxious stimuli in patients undergoing myocardial revascularization. The present study was designed to determine the hemodynamic profile in 10 patients and the time course of alfentanil plasma concentrations and pharmacokinetics (7 patients) during and following coronary artery surgery using alfentanil administration based on an overdosage principle. Premedication consisted of lorazepam, 0.07 mg/kg, given 2 hours before surgery. ⋯ Recovery time was short, despite the large amounts of narcotic used. It is concluded that very high doses of alfentanil associated with lorazepam premedication resulted in hemodynamic stability and markedly elevated narcotic plasma concentrations in most patients. Such plasma levels seem to provide satisfactory anesthetic conditions.
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J. Cardiothorac. Vasc. Anesth. · Feb 1991
A complete regional anesthesia technique for cardiac pacemaker insertion.
Sixteen consecutive adult patients scheduled for permanent transvenous cardiac pacemaker insertion received as their total anesthetic the combination of a cervical plexus block and blocks of the second, third, and fourth intercostal nerves using a combination of 1% mepivacaine and 0.2% tetracaine with epinephrine, 1:200,000. This technique consistently provided complete surgical anesthesia of the third cervical (C3) through the fourth thoracic (T4) dermatomes, without anesthesia of the brachial plexus. ⋯ In contrast to other reports, this technique provides surgical anesthesia that is adequate for all of the approaches used for transvenous pacemaker implantation, except for placement of a battery in an abdominal pouch. There were no serious complications and/or side effects in any of the patients studied.
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J. Cardiothorac. Vasc. Anesth. · Feb 1991
IPPV plus low-flow intermittent oxygen insufflation (end-exhalation to beginning inhalation) does not improve CO2 elimination.
It has been previously reported that continuous insufflation of low-flow O2 (0.05 to 0.20 L/kg/min), both supracarinally and subcarinally, in addition to intermittent positive-pressure ventilation (IPPV) (IPPV + O2 at a specific flow rate) caused progressive hemodynamic deterioration in patients. As demonstrated in a subsequent mechanical lung model, the hemodynamic deterioration was most probably due to lung hyperexpansion. The purpose of this study was to test the hypothesis that the O2 retarded the outflow of gas from the lung during exhalation and that if the insufflation were limited to the period of time from the end of tidal exhalation (EE) to the beginning of the next IPPV tidal inspiration (BI), lung hyperexpansion would not occur. ⋯ In the mechanical lung model and in the patients, a wide range of EE-BI O2 flow rates were used; respectively, 1 to 40 L/min and 0.05 to 0.20 L/kg/min. In the mechanical lung model, lung pressure and volume at EE and end-inspiration did not increase as long as the O2 flow was kept at or below 10 L/min. In the patients, airway pressure and hemodynamics did not change appreciably, but there was also no increase in CO2 elimination.(ABSTRACT TRUNCATED AT 250 WORDS)