Evaluation of the relationship between preoperative risk scores, postoperative and total length of stays and hospital costs in coronary bypass surgery.

OBJECTIVES: Several risk indices have been developed for the prediction of postoperative mortality and morbidity in coronary artery bypass operations, in which the risk scores are currently recorded as routine praxis. The aim of the present study was to determine whether the risk scores can be used to predict the hospital (LOS) and postoperative (POS) lengths of stay and total costs among coronary artery bypass graft (CABG) patients. METHODS: All first-time CABG patients (n=2104) treated at Helsinki University Central Hospital during 1997-1998 were preoperatively scored using the Cleveland Clinic preoperative model. A multivariate analysis was used to evaluate the effects of the risk scores on the LOS and POS and total costs. RESULTS: The mean preoperative risk score for the patients was 1.69. The increase in preoperative risk score was associated with an increase in the LOS (0.8 days by point), and POS (with 0.55 days by point). An age over 74 years increased the LOS by an extra day. The mean total cost for the CABG procedure was 8750 euros (SD 4430 euros). The costs increased as the risk score increased. Compared with the zero risk score, a score value of 2 was associated with a 1300 euros increase in total cost and a score value of over 6 was associated with an over 7000 euros cost increase. On average, the costs increased by 6980 euros (80%) for one major complication and by 935 euros (10%) in the elderly (>74 years of age). CONCLUSIONS: The results show that increasing risk scores were associated with longer postoperative hospital lengths of stay (POS and LOS) and with increased total costs. An age over 74 years appears to be an independent risk factor in increased POS, LOS and total cost. These results may help to estimate the impact of the preoperative risk profile on the resource requirement in CABG surgery.

Preoperative prediction of postoperative morbidity in coronary artery bypass grafting.

BACKGROUND: The risk factors of patients selected for coronary artery bypass grafting have increased in recent years because of the aging population. Prediction of postoperative complications is essential for optimal use of the available resources. The aim of this study was to develop a scoring method for prediction of postoperative morbidity of individual patients undergoing bypass grafting. METHODS: Data from 386 consecutive patients who underwent coronary artery bypass grafting in a single center were retrospectively collected. The relationship between the preoperative risk factors and the postoperative morbidity was analyzed by the Bayesian approach. Three risk indices (15-factor and seven-factor computed and seven-factor manual models) were developed for the prediction of morbidity. The criterion for morbidity was a prolonged hospital stay postoperatively (> 12 days) because of adverse events. RESULTS: The best predictive preoperative factors for increased morbidity were emergency operation, diabetes, rhythm other than sinus rhythm on the electrocardiogram or recent myocardial infarction, low ejection fraction (< 0.49), age greater than 70 years, decreased renal function, chronic pulmonary disease, cerebrovascular disease, and obesity. The sensitivity of the scoring methods ranged from 51% to 72% and the specificity, from 77% to 86%. CONCLUSIONS: The results show that individual patients can be stratified according to postoperative risk for complications on the basis of preoperative information that is available for most patients.

Non-invasive monitoring of finger arterial pressure in patients with Raynaud's phenomenon: effects of exposure to cold.

We studied the effects of exposure to cold on finger arterial pressure (FAP) measured by a finger arterial pressure monitor in 15 patients with Raynaud's phenomenon and in 15 healthy volunteers. The cold exposure induced vasoconstriction of the peripheral vascular bed as judged by the plethysmograph of a pulse oximeter and had marked effects on FAP values compared with upper arm arterial pressure. Immediately after the cold exposure, FAP decreased significantly (P less than or equal to 0.01) in both groups. However, during the subsequent 20 min, FAP values increased in relation to upper arm pressure. Finally, FAP values were greater than upper arm pressure in the control individuals, but not in patients with Raynaud's phenomenon. These results have implications for non-invasive monitoring of arterial pressure by the finger pressure device. Clinically, significant problems may arise in the monitoring of FAP in patients with a systemic connective tissue disease affecting peripheral circulation.

Single-lung allotransplantation in pigs: effects of two preservation methods on pulmonary gas exchange.

Single left lung allotransplantation was performed in 16 pigs to determine an optimal solution for lung preservation. Modified Euro-Collins and oxygenated fluorocarbon solutions (FC-43) were used as the lung preservative. Donors in both groups were pretreated with intravenous prostaglandin E1 infusions. The effects of the two different preservatives on ventilation and oxygenation were noninvasively monitored with capnometry and pulse oximetry. The functional results were further compared with morphologic findings. After implantation the right pulmonary artery was clamped, and the transplanted lung supported pulmonary circulation and ventilation. Arterial carbon dioxide tension (PaCO2) and arterial oxygen tension (PaO2) were measured from the arterial blood samples. The Euro-Collins group experienced hypercarbia (PaCO2, 54 to 72 mm Hg) and low end-tidal carbon dioxide (EtCO2) values (3.3% to 3.9%) when the donor lung was reimplanted and reperfused. The pigs in the Euro-Collins group were also hypoxemic after reimplantation of the left lung. The saturation (SpO2) values were 85% to 89%, and the PaO2 values were between 61 and 66 mm Hg. The oxygenated fluorocarbon group had normal ventilatory parameters and arterial oxygen saturation after reimplantation of the left lung; no significant gradient between EtCO2 and PaCO2 was detected. Scanning and transmission electron-microscopic studies of the transplanted lungs showed good to moderate preservation after reperfusion in the oxygenated fluorocarbon group, whereas preservation was judged to be moderate in the Euro-Collins group. Oxygenated fluorocarbon (FC-43) donor lung preservation thus resulted in superior functional recovery in pulmonary gas exchange during reperfusion compared with Euro-Collins solution. Electron-microscopic findings supported functional results obtained.

Pulse oximetry and finger blood pressure measurement during open-heart surgery.

Pulse oximeter arterial hemoglobin oxygen saturation (SpO2) and finger arterial pressure (FINAP) were continuously monitored before, during, and after cardiopulmonary bypass in 15 male patients. SpO2 was monitored simultaneously with two pulse oximeters, a Nellcor N-100 and an Ohmeda Biox III. The readings obtained from the two pulse oximeters were compared with arterial blood measurements obtained using a CO-oximeter. FINAP was monitored by a prototype device (Finapres) based on the Penaz volume-clamp method. FINAP was correlated with intraarterial pressure (IAP). Both pulse oximeters functioned well before cardiopulmonary bypass. The correlations with CO-oximeter values were 0.927 for the N-100 and 0.921 for the Biox III. Immediately after the onset of cardiopulmonary bypass, the N-100 pulse oximeter stopped displaying values. The Biox III pulse oximeter continued to display values during the cardiopulmonary bypass period; the correlation with CO-oximeter values was 0.813. After cardiopulmonary bypass, the N-100 began displaying values in 2 to 10 minutes. After cardiopulmonary bypass the correlation with CO-oximeter values was 0.792 for the N-100 and 0.828 for the Biox III pulse oximeter. The Finapres finger blood pressure device functioned well in 13 of 15 patients before cardiopulmonary bypass. The mean bias +/- precision of FINAP-IAP for mean pressure was 8.3 +/- 10.2 mm Hg (SD) and the correlation coefficient was 0.814. During cardiopulmonary bypass, the Finapres device functioned well in 10 of 15 patients. The mean bias precision of FINAP-IAP, for mean pressure in these 10 patients was 6.6 +/- 8.7 mm Hg and the correlation coefficient was 0.902.(ABSTRACT TRUNCATED AT 250 WORDS)