Journal of cardiothoracic and vascular anesthesia
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J. Cardiothorac. Vasc. Anesth. · Oct 1994
Influence of intravenous calcium gluconate on saphenous vein graft flow in closed-chest patients.
The effects of calcium gluconate on hemodynamics and saphenous vein graft flow in a group of patients undergoing elective coronary artery bypass grafting who developed ionized hypocalcemia at the end of the surgical procedure were examined. The patients received a central venous bolus of 15 mg/kg of calcium gluconate. Heart rate (HR), arterial pressure (AP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and cardiac output were measured immediately before and 30, 60, 120, 180, and 240 seconds after injection of calcium gluconate. ⋯ HR, CVP, PAP, PCWP, PVR, CI, SVI, and Vbypass-flow remained unaltered. It is concluded that calcium gluconate administered to moderately hypocalcemic patients increases arterial pressure mainly by peripheral vasoconstriction. Because the increase of arterial pressure, and, thereby, coronary perfusion pressure is not associated with an increase of LAD bypass flow, vasoconstriction in the coronary vascular bed distal to the venous graft cannot be ruled out, and deterioration of the myocardial oxygen supply/demand ratio is strongly suggested.
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J. Cardiothorac. Vasc. Anesth. · Aug 1994
Transesophageal pulsed-Doppler echocardiographic evaluation of transmitral and pulmonary venous flow during ventilation with positive end-expiratory pressure.
During mechanical ventilation with high levels of positive end-expiratory pressure (PEEP) several hemodynamic changes occur, the mechanism of which has been the subject of various previous studies. The effects of increasing levels of PEEP during mechanical ventilation were measured on left atrial and left ventricular filling dynamics, as assessed by pulmonary venous and transmitral flow velocities, respectively. Using transesophageal echocardiography in 12 patients, Doppler flow velocities of pulmonary venous and transmitral flow were studied at baseline (0 cmH2O PEEP) and at 5, 10, 15, and 20 cm H2O with 10-minute intervals, and once more after removal of PEEP. ⋯ In contrast, early and late diastolic velocities and velocity time integrals did not change. In regard to transmitral flow, both early and late diastolic velocities significantly decreased from 51 +/- 7 cm/s and 50 +/- 9 cm/s at baseline to 38 +/- 7 cm/s at 20 cmH2O PEEP, respectively (P < 0.01). Early and late diastolic velocity time integrals decreased from 6.1 +/- 1.8 cm and 4.7 +/- 1.0 cm to 4.5 +/- 1.0 cm (NS) and 3.4 +/- 0.7 cm (P < 0.05), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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J. Cardiothorac. Vasc. Anesth. · Aug 1994
Randomized Controlled Trial Clinical TrialAn amrinone bolus prior to weaning from cardiopulmonary bypass improves cardiac function in mitral valve surgery patients.
This double-blind, randomized study was performed to assess the effectiveness of a single bolus dose of 2 mg/kg of amrinone given during cardiopulmonary bypass (CPB) to patients undergoing mitral valve surgery. Outcome variables were hemodynamic function and the number and amount of vasopressors or inotropes required to wean from CPB. In amrinone-treated patients, cardiac index (CI) increased significantly by 48 +/- 14% following CPB (T3) versus 10 +/- 10% for placebo-treated patients (P = 0.029). ⋯ While on CPB, mean arterial pressure at 5 minutes following administration of the study drug was decreased in amrinone patients by 20 +/- 4% versus 4 +/- 3% in placebo patients (P = 0.005), but was no different at 10 and 15 minutes. There were no statistically significant differences in the number of patients who required supplemental inotropes or vasopressors either during CPB, following separation from CPB, or upon arrival in the ICU. Thus, amrinone improved CI without changing pulmonary vascular resistance or the requirement for supplemental inotropes or vasopressors in patients undergoing elective mitral valve surgery.
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J. Cardiothorac. Vasc. Anesth. · Aug 1994
Randomized Controlled Trial Comparative Study Clinical TrialThoracic epidural analgesia with bupivacaine and fentanyl for postoperative thoracotomy pain.
This study was designed to evaluate the potential fentanyl-sparing effect of a dilute local anesthetic, bupivacaine, administered in fixed combinations with fentanyl for post-thoracotomy analgesia via a continuous thoracic epidural infusion. Forty adult patients scheduled for thoracotomy were randomly allocated in a double-blind fashion to receive an epidural infusion containing 0, 0.03, 0.06, or 0.125% bupivacaine in combination with fentanyl (4 micrograms/mL). The epidural infusions were initiated in the operating room at 10 mL/hr. ⋯ Arterial blood gas measurements performed on the morning after surgery revealed significant reductions in PaCO2 values, 38 +/- 4, 36 +/- 4, 37 +/- 4 mmHg for 0.03, 0.06, and 0.125% bupivacaine groups respectively, versus 44 +/- 6 for the plain fentanyl group. Arterial pH values were significantly higher in all bupivacaine treatment groups. These findings suggest that the combination of dilute bupivacaine with fentanyl for thoracic epidural analgesia for post-thoracotomy pain may have beneficial effects on pulmonary gas exchange.