Mark N. Gomez

A cost/benefit analysis of randomized invasive monitoring for patients undergoing cardiac surgery

The aim of this study was to determine the effect of choice of invasive monitoring on cost, morbidity, and mortality in cardiac surgery. Two hundred and twenty-six adults undergoing elective cardiac surgery were initially assigned at random to receive either a central venous pressure monitoring catheter (group I), a conventional pulmonary artery (PA) catheter (group II), or a mixed venous oxygen saturation (S&OV0540;O2) measuring PA catheter (group III). If the attending anesthesiologist believed that the patient initially randomized to group I should have a PA catheter, that patient was then reassigned to receive either a conventional PA catheter (group IV) or S&OV0540;O2 measuring PA catheter (group V). The total costs were defined as the total amount billed to the patient for the catheter used; the professional cost of its insertion; and the determinations of cardiac output, arterial blood gas tensions, hemoglobin level, and hematocrit. Mean total monitoring and laboratory costs in Group I (

Intrapleural bupivacaine ν saline after thoracotomy—effects on pain and lung function—a double-blind study

591 ± 67) were statistically significantly (P < 0.05) less than costs in Group II (

Dose-response relationship of isoflurane and halothane versus coronary perfusion pressures. Effects on flow redistribution in a collateralized chronic swine model.

856 ± 231). Further, mean monitoring and laboratory costs in Group II were statistically significantly (P < 0.05) less than those in Group III (

Magnesium and Cardiovascular Disease

1128 ± 759). Patients in group IV incurred mean total costs of

Limited Lateral Thoracotomy: Improved Postoperative Pulmonary Function

986 ± 578, while those in group V had mean total costs of

Pro: right-sided double-lumen endotracheal tubes should be routinely used in thoracic surgery.

1126 ± 382 (NS). There were no significant differences between any of the groups with respect to length of stay in the intensive care unit, morbidity, or mortality. We conclude that use of a central venous pressure monitoring catheter was justified in low risk cardiac surgical patients, and that when PA catheters were used, additional costs were incurred. Additionally, monitoring of S&OV0540;O2 adds significant cost to that incurred with routine PA catheter use, but produces no discernible difference in patient outcome.

INTRAPLEURAL BUPIVACAINE FOR INTRAOPERATIVE ANALGESIA - A DANGEROUS TECHNIQUE?

The effects of intrapleural (IP) bupivacaine on pain, morphine requirement, and pulmonary function were evaluated in 15 patients for 24 hours after thoracotomy. An IP catheter was placed during surgery. Patients were randomized in a double-blind fashion to receive 1.5 mg/kg of 0.5% bupivacaine IP or saline on two occasions, eight hours apart. A standard anesthetic with thiopental, oxygen, isoflurane, and nondepolarizing muscle relaxant was given. Pain was evaluated with a visual analog pain score every hour, and forced vital capacity (FVC), forced expiratory volume one second (FEV1), peak expiratory flow (PF), and forced expiratory flow 25% to 75% (FEF) were measured 1, 2, 4, 8, and 24 hours postoperatively as well as before and 30 minutes after each IP injection. Arterial blood gases were sampled 1, 2, 8, and 24 hours postoperatively. Plasma bupivacaine concentrations were measured in 10 patients 5, 10, 20, 30, 60, 120, and 180 minutes after IP injection. With each IP bupivacaine injection, the pain score and morphine requirement decreased. There was a significant improvement in all pulmonary function tests in the patients receiving bupivacaine, but no change in the saline controls. The analgesic effect was shortlived (two to five hours), possibly because of loss of bupivacaine in the chest drains. No differences were seen between the two groups after the effect of IP bupivacaine had worn off. Plasma bupivacaine levels had a Cmax of 0.44 to 1.50 micrograms/mL, with a Tmax at 5 to 30 minutes with levels well below 2 to 4 micrograms/mL where increasing toxicity is seen.

INTRAPLEURAL BUPIVACAINE VS SALINE AFTER THORACOTOMY - EFFECTS ON PAIN AND LUNG FUNCTION - A DOUBLE BLIND STUDY

The authors studied the redistribution of myocardial blood flow in a collateral-dependent (CD) zone as a function of coronary perfusion pressure (CPP) during isoflurane and halothane anesthesia. A swine model with CD myocardium distal to a chronically occluded left anterior descending coronary artery was developed and studied. Sixteen piglets were allowed to grow for 8-10 weeks after banding of the left anterior descending coronary artery. They were randomly anesthetized with either isoflurane (n = 8) or halothane (n = 8) as the sole anesthetic, which was used to regulate specific CPP. The resultant regional myocardial blood flows were measured using radiolabeled microspheres. Four randomly allocated CPPs, of 30, 40, 45, and 55 mmHg, were studied in each animal. Four additional collateralized animals were anesthetized with alpha-chloralose, and the same CPPs were obtained using an intravenous adenosine infusion (1-5 microM kg-1) to validate this model. There was a proportional decrease in heart rate and blood pressure in both the isoflurane and and the halothane group with CPP. Cardiac output was significantly decreased in the halothane group at 30 mmHg when compared to 55-mmHg CPP, but it was maintained in the isoflurane group. Systemic vascular resistance was significantly lower in the isoflurane group at 30 and 40 mmHg when compared to 55-mmHg CPP. Both the isoflurane and the halothane group showed a proportional and significant decrease in endo-, mid-, and epicardial blood flows at 30-mmHg CPP when compared to baseline. In both CD and normal perfusion zones, isoflurane consistently sustained a higher endocardial blood flow than halothane (5.7-41.1%).(ABSTRACT TRUNCATED AT 250 WORDS)