Journal of cardiothoracic and vascular anesthesia
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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 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.
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J. Cardiothorac. Vasc. Anesth. · Aug 1994
Effects of atrial natriuretic peptide on renal function after cardiac surgery and in cyclosporine-treated heart transplant recipients.
The study investigated the effects of intravenous infusion of atrial natriuretic peptide (human ANP 99-126) on renal function and central hemodynamics after coronary artery bypass grafting (CABG), and the ability of ANP to reverse the acute nephrotoxic effects of cyclosporine after heart transplantation. Ten patients with an EF > 0.5 and normal renal function were studied 2 to 4 hours after CABG surgery. Furthermore, six heart transplant recipients receiving cyclosporine for immunosuppression who developed renal dysfunction 2 to 4 days after transplantation were studied. ⋯ In the heart transplant recipients, baseline GFR was markedly reduced compared to pretransplantation values (-65%). UF, GFR, and RBF increased 240%, 69%, and 53%, respectively, while renal vascular resistance decreased 45% during the highest dose of ANP infused. At this ANP dose level, circulating ANP concentrations were sixfold to eightfold higher than the preinfusion control level.(ABSTRACT TRUNCATED AT 250 WORDS)