Biomedical subjects

Jeng-Shing Wang

Publications and source records attributed to Jeng-Shing Wang.

4 recordsLinked to original sources

PubMed2006

Effect of lung resection on exercise capacity and on carbon monoxide diffusing capacity during exercise.

OBJECTIVE: To evaluate the effect of lung resection on lung function and exercise capacity values, including diffusion capacity of the lung for carbon monoxide (Dlco), during exercise, and to determine whether postoperative lung function, including exercise capacity and Dlco during exercise, could be predicted from preoperative lung function and the number of functional segments resected. DESIGN: Prospective study. SETTING: Clinical pulmonary function laboratory in a university teaching hospital. PATIENTS: Twenty-eight patients undergoing lung resection at Vancouver General Hospital from October 1998 to May 1999, were studied preoperatively and 1-year postoperatively. INTERVENTIONS: We determined FEV(1) and FVC, and maximal oxygen uptake (Vo(2)max) and maximal workload (Wmax) achieved during incremental exercise testing. We used the three-equation modification of the single-breath Dlco technique to determine Dlco at rest (RDlco) and during steady-state exercise at 70% of Wmax, and the increase in Dlco from rest to exercise (ie, the mean increase in Dlco percent predicted at 70% of Wmax from resting Dlco percent predicted [(70%-R)Dlco]). We calculated the predicted postoperative (PPO) values for all the above parameters using the preoperative test data and the extent of functioning bronchopulmonary segments resected, and compared the results with the actual 1-year postoperative results. RESULTS: Following lung resection, there was a significant reduction in FEV(1), FVC, and Dlco with decreases of 12%, 13%, and 22% predicted, respectively. There were also significant decreases in Vo(2)max per kilogram of 2.1 mL/min/kg (8% of predicted Vo(2)max) and in Wmax of 12 W (7% of predicted Wmax). However, (70%-R)Dlco did not significantly decrease after lobectomy but decreased after pneumonectomy. The calculated PPO values significantly underestimated postoperative values after pneumonectomy but were acceptable for lobectomy. CONCLUSIONS: Exercise tests may be better indicators of functional capacity after lung resection than measurements of FEV(1) and FVC or RDlco. PPO results calculated by estimating the functional contribution of the resected segments, are comparable with those obtained using ventilation-perfusion lung scanning and significantly underestimate postoperative lung function after pneumonectomy, but are acceptable for lobectomy.

Aged↗

PubMed2004

Pulmonary function tests in preoperative pulmonary evaluation.

Pulmonary function testing (PFT) has been used to evaluate the risk for postoperative complications since the 1950s. PFT including spirometry, lung volumes, diffusing capacity, oximetry, and arterial blood gases has been used to assess the postoperative risk of lung resection. In selected cases, additional evaluation may include radionuclide lung scanning, exercise testing, invasive pulmonary hemodynamic measurements, and risk stratification analysis. A new index, predicted postoperative product (PPP), was found to have strong predictive ability for mortality. We defined a new useful index, measured product (MP), to predict postoperative complications; MP had similar advantages of PPP. Since diffusing capacity at rest has been shown to be a good predictor of postoperative complications following lung resection, and since exercise testing has been also useful in preoperative evaluation prior to lung resection, we reasoned that evaluation of the effect of exercise on diffusing capacity would be helpful to evaluate the ability of the pulmonary capillary bed to expand and increase its capacity to transfer gas during exercise.

Exercise Test↗

PubMed2003

Relationship of carbon monoxide pulmonary diffusing capacity to postoperative cardiopulmonary complications in patients undergoing pneumonectomy.

This retrospective analytic study evaluated whether abnormal diffusing capacity for carbon monoxide (DLCO) is a predictor of postoperative morbidity and mortality in patients undergoing pneumonectomy for lung cancer. The medical records of patients undergoing pneumonectomy at Vancouver General Hospital between January 1992 and December 1997 were reviewed. Postoperative complications occurring within 30 days of resection were classified into mortality, and cardiovascular, pulmonary, and technical complications. A total of 151 pneumonectomy cases were reviewed. There were 100 men (66%) and 51 women (34%) with a mean age of 61 years. Complications occurred in 73 patients (48%), including mortality in eight (5%), cardiovascular morbidity in 50 (33%), pulmonary morbidity in 30 (20%), and technical morbidity in 22 (15%). Arrhythmia (21%) and pulmonary edema (13%) were the two major cardiovascular complications. Patients with complications had a greater smoking history, a longer hospital stay, a lower forced expiratory volume in 1 second (FEV1), a lower FEV1/forced vital capacity (FVC) ratio, a lower DLCO, and a lower DLCO/alveolar volume (VA) ratio than patients without complications. A DLCO of 70% predicted was the best functional predictor of postoperative complications, with a complication rate of 94% in patients with a DLCO of less than 70% predicted compared with 27% in patients with a DLCO of at least 70% predicted (sensitivity, 62%; specificity, 96%). However, technical morbidity was not related to preoperative lung function variables, including DLCO. Patients with a DLCO of at least 70% predicted had a low postpneumonectomy complication rate. Although cardiac arrhythmia was the major cause of morbidity, pulmonary edema was the major cause of mortality.

Adult↗

PubMed2003

Relationship of predicted postoperative product to postpneumonectomy cardiopulmonary complications.

BACKGROUND: This retrospective analytic study was to evaluate diffusing capacity of the lung for carbon monoxide (DLCO) and predicted postoperative product (PPP) as predictors of postpneumonectomy cardiopulmonary complications. METHODS: One-hundred fifty-one patients underwent pneumonectomy at Vancouver General Hospital from January 1992 to December 1997. The PPP was obtained by multiplying the predicted postoperative (ppo) FEV1 by the ppo DLCO, both expressed as % of predicted. The ppo FEV1 and DLCO were derived by calculating the proportional loss of functional lung from the resected lung. We also evaluated a new index, the measured product (MP), obtained by multiplying the measured preoperative FEV1 by DLCO, both expressed as % of predicted. RESULTS: Patients with complications had lower FEV1, lower DLCO, lower MP, lower ppo FEV1, lower ppo DLCO, and lower PPP than patients without complications. DLCO at 70% of predicted was the best predictor of postoperative complications, while PPP at 1400 was similar to MP at 5000 and ppo DLCO at 40% of predicted in predicting postoperative complications. The complication rate was 88% in patients with DLCO < 70% of predicted, compared with a complication rate of 19% in patients with DLCO > or = 70% of predicted (sensitivity = 68%, specificity = 93%), while the complication rate was 66% in patients with PPP < 1400, compared with a complication rate of 25% in patients with PPP > or = 1400 (sensitivity = 63%, specificity = 78%). CONCLUSIONS: DLCO < 70% of predicted is associated with increased risk of complications following pneumonectomy. PPP determined preoperatively allows a patient with a critically low value (< 40% of predicted) for one variable (either ppo FEV1 or ppo DLCO) to be accepted for surgery on the basis of a good value in the other. Patients with PPP > or = 1400 have a relatively low postpneumonectomy complication rate.

Female↗