Biomedical subjects
Publications and source records attributed to Scott J Swanson.
Several issues are involved in determining a patient's risk for postoperative hemorrhage and in managing this potential postoperative complication. The impact of minimally invasive procedures on the incidence of this complication is addressed in this article.
PURPOSE: Surgeons converting their open lobectomy skills to video-assisted thoracic surgery (VATS) techniques have sought traditional technical courses, publications, and physician mentoring. While these are useful in teaching basic principles, it is more difficult to promulgate the numerous advanced techniques or technical "tricks" that deal with anatomical variations or pathologic changes in the lung tissue. DESCRIPTION: Engineers have simplified the process of rolling out complex technology by using troubleshooting guides. Accordingly, helpful video-assisted lobectomy maneuvers have been categorized according to the specific problems occasionally encountered at different points in the operation. EVALUATION: These maneuvers were compiled and reviewed by a panel of thoracic surgeons experienced in video-assisted lobectomies and have been active in teaching and mentoring of thoracic surgeons, residents and fellows. The techniques described have been used successfully by the authors to overcome exposure and instrumentation limitations, to achieve the outcomes reported in their series, and to guide trainees. CONCLUSIONS: Troubleshooting guides offer an organized means for surgeons to improve the parts of the video-assisted lobectomy procedure that they find tedious or challenging.
BACKGROUND: Interferon-gamma, produced by T-helper cells, activates macrophages and increases expression of major histocompatibility complex (MHC) products in acute and chronic rejection. We investigated the role of interferon-gamma in murine heterotopic tracheal allografts. METHODS: Tracheas from BALB/c mice were heterotopically transplanted to BALB/c (12 isografts: 2 weeks [n = 6] and 4 weeks [n = 6], C57BL/6 (12 allografts: 2 weeks [n = 6] and 4 weeks [n = 6]) and C57BL/6 interferon-gamma knockout mice (12 interferon-gamma knockout allografts: 2 weeks [n = 4] and 4 weeks [n = 8]). BALB/c interferon-gamma knockout tracheas were transplanted to C57BL/6 mice (reverse knockout: 4 weeks [n = 6]) and BALB/c interferon-gamma knockout mice (4 weeks [n = 2]). C57BL/6 tracheas were transplanted to Bm12 mice (MHC Class II mismatch allografts: 4 weeks [n = 6]). Conventional histology and immunohistochemistry for CD4, CD8 and CD11b were performed. RESULTS: Minimal (<20%) obliteration was seen at 2 weeks in the allograft groups. No obliteration was seen in the isograft groups. However, all allografts were completely obliterated at 4 weeks. Interferon-gamma knockout allograft combinations displayed severe rejection characterized by intense intra- and extraluminal infiltration by CD4-, CD8- and CD11b-labeled cells. The MHC Class II mismatch allograft group showed normal epithelium and mild sub-epithelial infiltration by CD4+ cells at 4 weeks (CD8-, CD11b-). CONCLUSIONS: Absence of interferon-gamma does not protect the allograft from obliteration. Epithelial destruction by cytotoxic T cells appears to be an important mechanism in the development of obliteration in murine heterotopic tracheal allografts.
OBJECTIVE: Extrapleural pneumonectomy for therapy of mesothelioma has been associated with significant perioperative mortality and morbidity. Postoperative complications of this procedure require a unique management approach. We developed treatment algorithms for most of the common complications of extrapleural pneumonectomy resulting in reduced mortality and hospital stay. Complications after extrapleural pneumonectomy were further analyzed to elucidate means of prevention, early detection, and treatment. METHODS: A total of 496 patients undergoing extrapleural pneumonectomy were reviewed for mortality rates, with a subset of 328 consecutive patients between 1980 and 2000 who were examined for detailed morbidity data by using a prospective clinical database. RESULTS: Median age was 58 years (range, 28-77 years), with a 10-day (range, 4-101 days) median length of stay. One hundred ninety-eight (60.4%) of 328 patients experienced minor and major complications, and 11 of 328 patients died, for an overall mortality rate of 3.4%. Complications included the following: atrial fibrillation (145 [44.2%]), prolonged intubation (26 [7.9%]), vocal cord paralysis (22 [6.7%]), deep vein thrombosis (21 [6.4%]), technical complications (patch dehiscence, hemorrhage, or both; 20 [6.1%]), tamponade (12 [3.6%]), acute respiratory distress syndrome (12 [3.6%]), cardiac arrest (10 [3%]), constrictive physiology (9 [2.7%]), aspiration (9 [2.7%]), renal failure (9 [2.7%]), empyema (8 [2.4%]), tracheostomy (6 [1.8%]), myocardial infarction (5 [1.5%]), pulmonary embolus (5 [1.5%]), and bronchopleural fistula (2 [0.6%]). Clinical data demonstrated the following: (1) prophylaxis for atrial fibrillation is recommended; (2) early ambulation, aspiration precautions, endoscopic assessment of the vocal cords, and avoidance of fluid overload are crucial; (3) perioperative diagnosis and aggressive management of deep vein thrombosis are important; (4) immediate reoperation and open cardiac massage are essential for relief of cardiac herniation and tamponade from cardiac patch dysfunction; (5) diaphragmatic patch dehiscence, hemorrhage, or both require immediate reoperation; (6) early signs of infection might indicate bronchopleural fistula or empyema and should be treated with thoracoscopic or open drainage and staged removal of patch material; and (7) excessive perioperative mediastinal shift is treated with a catheter placed intraoperatively. CONCLUSION: Complications after extrapleural pneumonectomy require a unique approach to management, and mortality can be minimized by early detection and aggressive treatment.
BACKGROUND: Small population studies have reported higher survival rates for women than men with non-small cell lung carcinoma (NSCLC). Because human NSCLC cells express estrogen receptors, we evaluated hormonally active and inactive women to identify biologically mediated differences. METHODS: A total of 14,676 US women with stage I through IV primary non-small cell lung cancer (NSCLC) from the 1992 to 1997 Surveillance, Epidemiology, and End Results database were grouped into two categories based on the average menopausal age of 51 years as defined by the American College of Obstetricians and Gynecologists: ages 31 to 50 premenopausal (n = 2,230, 15%) and ages 51 to 70 postmenopausal (n = 12,446, 85%). Extreme ages were excluded. Statistics were calculated with chi(2) or Mann-Whitney tests, Kaplan-Meier estimates with log-rank tests, and Cox proportional hazards models. RESULTS: Premenopausal women more commonly presented with advanced clinical stage, less favorable histology (adenocarcinoma), and poorly differentiated tumors, and more often underwent pneumonectomies. Surgery with curative intent was performed in 31% premenopausal and 33% postmenopausal women (p = 0.03). Overall survival for premenopausal and postmenopausal women was not significantly different (median 10 and 9 months, all stages; 70 and 71 months, stages I and II). Adjusting for significant covariates (stage, histology, size, grade, extent of surgery), postmenopausal women had higher lung-cancer-related deaths (hazard ratio, 1.14; 95% confidence interval, 1.03 to 1.27). CONCLUSIONS: Premenopausal women presented more often with advanced disease and underwent more extensive resection, yet had survival advantage after covariate adjustment. Additionally, postmenopausal women had a survival advantage compared with their male counterparts. Results suggest that estrogen exposure creates a milieu that may confer a protective effect through some yet unknown mechanisms that determine outcome of the neoplastic process and warrant further investigation.
OBJECTIVE: To determine the clinical impact of early versus late surgical therapy for new onset unilateral vocal cord paralysis (UVCP) after thoracic surgery. STUDY DESIGN: Patients diagnosed with new onset UVCP after esophagectomy, pneumonectomy or pulmonary lobectomy were reviewed to determine the incidence of pneumonia, need for postoperative bronchoscopy and length of stay (LOS). Comparisons were made between patients undergoing early (< or = 4 days after thoracic procedure) versus late rehabilitation (> or = 5 days after thoracic procedure) of their UVCP with vocal cord medialization. RESULTS: Some 86 patients (27 esophagectomies, 43 pneumonectomies and 16 lobectomies) with new onset UVCP were examined. A total of 32 patients (37.2%) underwent early vocal cord medialization and 54 (62.8%) underwent late repair. The pneumonia rate for patients undergoing early vocal cord medialization (6.3%) was significantly lower than the rate for vocal cord medialization (37.0%, P=0.001, chi(2)). Early medialization patients required fewer postoperative bronchoscopies (mean number of bronchoscopies, 0.26) than late medialization patients (mean bronchoscopies, 0.94, P=0.013). The median LOS was significantly decreased for early versus late medialization patients in both pneumonectomy (reduction in LOS of 8 days) and lobectomy groups (reduction in LOS of 7 days). CONCLUSIONS: Early vocal cord medialization decreases the pneumonia rate, the requirement for postoperative bronchoscopies and the LOS for patients suffering from new onset UVCP after thoracic surgery. SIGNIFICANCE: Consideration should be given to early medialization for new onset UVCP when medically sound.
This paper examines potential physiological mechanisms responsible for improvement after lung volume reduction surgery (LVRS). In 25 patients (63 +/- 9 yr; 11 men, 14 women), spirometry [forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC)], lung volumes [residual volume (RV) and total lung capacity (TLC)], small airway resistance, recoil pressures, and respiratory muscle contractility (RMC) were measured before and 4-6 mo after LVRS. Data were interpreted to assess how changes in each component of lung mechanics affect overall function. Among responders (DeltaFEV(1) > or = 12%; 150 ml), improvement was primarily due to an increase in FVC, not to FEV(1)-to-FVC ratio. Among nonresponders, FEV(1), FVC, and RV/TLC did not change after surgery, although recoil pressure increased in both groups. Both groups experienced a reduction in RMC after LVRS. In conclusion, LVRS improves function in emphysema by resizing the lung relative to the chest wall by reducing RV. LVRS does not change airway resistance but decreases RMC, which attenuates the potential benefits of LVRS that are generated by reducing RV/TLC. Among nonresponders, recoil pressure increased out of proportion to reduced volume, such that no increase in vital capacity or improvement in FEV(1) occurred.
VATS is a relatively new technology that has become the standard of care for basic procedures such as drainage of pleural effusion and blebectomy. VATS anatomic lung resection is more controversial. Published studies demonstrate several advantages of VATS over a standard posterolateral thoracotomy. A minimally invasive approach causes less inflammatory reaction. Acute and chronic pain are diminished. As a result, the length of hospitalization is shorter. Early and late shoulder dysfunction is less and return to work time is shorter. Taken together, these factors suggest a better overall outcome using a VATS approach. From an oncologic standpoint, lymph node dissection can be accomplished and locoregional recurrence is low. The validity of VATS for lung cancer will be determined by long-term data. A phase III national (intergroup) protocol is being drafted and will help to answer these questions.