Biomedical subjects
Publications and source records attributed to D S Mulder.
Despite its proven safety and efficacy, complications from the Greenfield vena cava filter have been described. We report the unusual case of a duodenal perforation by a filter in a 29-yr-old male. The diagnosis was made incidentally at endoscopy.
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Isolated trauma to the airway is infrequent yet potentially life-threatening. The larynx and cervical trachea are vulnerable to external forces, whether penetrating or blunt, as well as internal injuries from endotracheal or nasogastric intubation and to thermal burns from the inhalation of fumes or the ingestion of caustic substances.
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Societal, technologic, organizational and educational developments during the past 10 years have brought about increasing promises for change in the graduate medical education of cardiac and thoracic surgeons. These changes effectively lengthened training to 8'years and created a double standard for the education of a thoracic surgeon. A task force mandated by the Royal College of Physicians and Surgeons of Canada nucleus committees in both cardiac and thoracic surgery and with the support of the Canadian Society of Cardiovascular and Thoracic Surgeons studied the problem and made the following recommendation: cardiac surgery and thoracic surgery should each become a primary specialty with its own nucleus committee. Each specialty would require 6'years' training, with the possibility of obtaining certification in both specialties after an additional 18'months training. Each specialty could also be entered after completion of full training in general surgery. The task force also urged the development of a curriculum to guide educational objectives in each specialty. These changes will produce a flexible, shorter, more focused program for cardiac and thoracic surgeons for both university and community settings.
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Many lung transplant programs consider ventilator dependence as a contraindication for transplantation. Among 54 patients in whom bilateral lung transplantations for cystic fibrosis were performed by the Joint Marseille-Montreal Lung Transplant Program, 10 were ventilator dependent. Three of them died in the early postoperative period (30%): 2 as a result of cerebral anoxia and sepsis, 1 of Pseudomonas cepacia pneumonia. Two patients died at 15 and 19 months after transplantation of obliterative bronchiolitis and secondary bacterial pneumonitis. Another 2 patients in whom obliterative bronchiolitis developed underwent retransplantation with a heart-lung block; 1 of those was operated on at 12 months and is well at 29 months after his initial transplantation; the second was operated on at 34 months and died of primary graft failure. Three other patients are alive and well at 3, 11, and 14 months after transplantation. Actuarial survival at 1 year was 70%. The postoperative course and the infectious and rejection complications were no different from those in patients who underwent transplantation while spontaneously breathing. Obliterative bronchiolitis developed in 66% of patients at risk (2 of 6 patients surviving more than 6 months). We conclude that transplantation in mechanically ventilated patients with cystic fibrosis is not associated with an increase in morbidity or mortality after bilateral lung transplantation. Long-term survival, as in patients who undergo transplantation while spontaneously breathing, is limited by the development of obliterative bronchiolitis.
Thoracic surgeons have recently pursued innovative techniques that can help minimize postoperative pain. These have taken two basic directions. The first consists of a modification of the operative procedure itself, such that the surgical insult and hence the resulting pain are minimized. Modifications of the conventional thoracotomy technique have led to the development of the muscle-sparing thoracotomy and the linear or small transaxillary thoracotomy. The ultimate modification has been video-assisted thoracic surgery techniques, which are associated with a marked reduction in postoperative pain. The second approach centers on techniques that improve postoperative pain control. The recently published Agency Health Care Policy and Research guidelines provide a comprehensive review of the therapeutic options for postoperative pain control. These guidelines emphasize the value of nonsteroidal antiinflammatory drugs in conjunction with opioids as the preferred form of analgesia. Many authors have advocated the induction of spinal analgesia after thoracotomy, using either epidural opioids or local anesthesia, or both. Patient-controlled analgesia and multiple intercostal nerve blocks are other methods for managing postthoracotomy pain. The potential benefits conferred by aggressive pain control after thoracotomy are enormous for the patients, the surgeons, and the entire health-care system.
A 4-month "minisabbatical" (June through September 1992) provided me with a selected view of the current status of thoracoscopic surgery as it is being performed in Europe. This experience comprised visits to three countries and a total of five clinical units doing endoscopic surgery. Observations are grouped into five categories: (1) the clinical spectrum of thoracoscopic procedures, (2) operating room design, (3) the evolution of instrumentation and imaging, (4) educational programs, and (5) strategies for testing innovative technologies. This short visit convinced me of the need for greater communication with our European colleagues.
OBJECTIVE: This study assessed the reliability and safety of VATR for treatment of peripheral T1 lung cancer in high-risk patients. SUMMARY BACKGROUND DATA: Surgical resection is the best therapy for stage I lung cancer. Patients with poor cardiopulmonary status or those who are elderly (> 75 years of age) are considered to be at high risk from thoracotomy and are frequently referred for radiation therapy or expectant palliative management. Data from previous studies suggest that survival with wedge resection is similar to that with lobectomy. The authors propose VATR, which is minimally invasive, as a therapeutic option in patients considered to be at high risk for resection by thoracotomy. METHODS: Between November 1990 and November 1992, more than 400 thoracoscopic lung resections were performed. Thirty patients with poor pulmonary function (forced expiratory volume FEV1] < 1 L or < 35% predicted; arterial oxygen tension [PaO2] < 60 mmHg on room air; diffusion capacity [DCO] < 40%) underwent 31 VATRs (1 patient had a staged procedure for bilateral synchronous lung cancers). All patients had T1 peripheral lesions with no bronchoscopically visible lesions. Computed tomography of the chest revealed no evidence of mediastinal disease in all patients. RESULTS: Patients had a mean FEV1 value of 0.9 L (38% predicted) and a mean age of 71 years. Tumors were located in left upper lobe (LUL) in 13 patients, in right lower lobe (RLL) in 7 patients, in right upper lobe (RUL) in 6 patients, in left lower lobe (LLL) in 4 patients, and in right middle lobe (RML) in 1 patient. Computed tomography-guided wire localization, methylene blue surface injection, and intraoperative ultrasonography were used to assist in defining difficult lesions. All lesions were successfully resected without converting to thoracotomy. One patient died on the 34th postoperative day of myocardial infarction (operative mortality rate of 3%). Five patients had prolonged air leaks (< 5 days), with a median chest tube time of 3 days. Two patients experienced pneumonia. CONCLUSION: The authors concluded that VATR is a safe and reliable procedure for treatment of peripheral T1 lung cancer in high-risk patients. Long-term follow-up will be required to determine the efficacy of this procedure regarding survival and locoregional recurrence.
A sample of 360 severely injured patients was selected from a cohort of 8007 trauma victims followed prospectively from the time of injury to death or discharge. A case referent study was used to test the association between on-site care, total prehospital time, and level of care at the receiving hospital with short-term survival. Multiple logistic regression analyses showed that use of Advanced Life Support (ALS) at the scene was not associated with survival, whereas treatment at a level I compatible hospital was associated with a 38% reduction in the odds of dying, which approached statistical significance. Total prehospital time over 60 minutes was associated with a statistically significant adjusted relative odds of dying (OR = 3.0). The results of this study support the need for regionalization of trauma care and fail to show a benefit associated with ALS.
Differentiation between rejection and infection of lung allografts remains difficult. The effects of these two pathologic entities on the cytolytic activity of bronchoalveolar lavage (BAL) and PBL were investigated. Left lung allotransplantation was performed on 16 mongrel dogs of which 12 were available for complete studies. All animals received CA, AZA, and PRED for 2 weeks. Four grafts developed left lower lobe Gram negative pneumonia. The eight remaining recipients progressed gradually to severe rejection after acute reduction of immunosuppression. Cytolytic activity of blood and left lung BAL lymphocytes was quantitated by the natural killer (NK) and lectin-dependent cell-mediated cytotoxicity (LDCMC) assays. Two additional groups serving as controls were either given a 10-day course of immunosuppressants or had right lower lobe pneumonia induced by transbronchial inoculation of gram negative bacteria. Immunosuppressed control animals showed significant depression of PBL and BAL lymphocyte LDCMC and NK activity. Similarly, BAL lymphocytes expressed very low LDCMC in normal allografts (2.8 +/- 0.8%). Once rejection developed and progressed, LDCMC became significantly higher (15.6 +/- 2.2 and 52.7 +/- 2.8% in mild and severe rejection, respectively). There was no detectable NK activity in rejecting lung allografts. BAL lymphocytes from infected allografts, on the other hand, showed an elevation of both NK and LDCMC activity (9.1 +/- 1.1 and 14.6 +/- 1.0%, respectively). Similarly, bacterial pneumonia in control animals manifested an increase in NK and LDCMC activity in lung and blood. PBL lymphocytes of lung allograft recipients, however, had increased NK and LDCMC activity in both rejection and infection. LDCMC/NK activity ratio (LM/NK index) of lung lymphocytes was significantly higher in rejecting allografts (11.2 +/- 1.0 and 12.4 +/- 1.6 for mild and severe rejection, respectively) than in infected ones (1.2 +/- 0.3, P < 0.0001). It appears, from this study, that rejection of the lung allograft results in alterations in BAL lymphocyte phenotypes and functions that differ from those associated with bacterial infection. Such differences may be useful in distinguishing episodes of acute allograft rejection from bacterial infection.
Extracorporeal cardiopulmonary bypass (CPB) has been associated with a wide variety of immunological derangements, including a transient postoperative impairment of lymphocyte function. We examined changes in phenotypic and nonspecific cytotoxicity of peripheral blood mononuclear cells after extracorporeal CPB. The peripheral blood samples obtained from 10 patients were subjected to natural killer and cytotoxic T lymphocyte activity assay before and at intervals after CPB. Phenotypic analysis of peripheral blood lymphocytes was performed in 5 patients before and immediately after CPB. We observed a significant increase in peripheral blood CD8+ cells (cytotoxic/suppressor T lymphocytes) (16.1% +/- 2.5% versus 22.5% +/- 2.1%; p less than .005) and a decrease in CD4+ cells (helper/inducer T lymphocytes) (46.1% +/- 3.5% versus 36.1% +/- 3.5%; p less than 0.02) immediately after extracorporeal circulation. The CD8/CD4 ratio in peripheral blood was significantly increased immediately after bypass (0.53 versus 0.80; p less than 0.001). No significant changes in percentages of other leukocyte subsets in peripheral blood were noted. The activity of cytotoxic T lymphocytes and natural killer cells in peripheral blood was impaired on postoperative days 1 and 3 but was restored to preoperative values by removal of mononuclear phagocytes from these cells. The decrease in natural killer cell and cytotoxic T lymphocyte activity in peripheral blood may signify a temporary impairment of the effector arm of the cell-mediated immunity in the post-operative period. The observed changes in peripheral blood phenotype and function may be involved in early organ injury and infectious complications after CPB.
One hundred twenty cystic fibrosis patients were accepted for transplantation. Twenty-five patients underwent double-lung transplantation. Twenty-five patients died awaiting transplantation (20.6%). There were 13 female and 12 male patients. Their mean age was 28 years (range, 7 to 34 years), and mean percentage ideal body weight was 76% (range, 58.5% to 91.9%). Most patients were hypoxic and hypercarbic. Two patients underwent tracheal anastomosis, 15 had en bloc bronchial anastomoses, and 8 had sequential single-lung transplants. Operative mortality was 16%; all deaths were related to bleeding from extensive adhesions. Actuarial survival at 1 year was 64%. Rejection and infection were frequent during the first month and decreased thereafter. Airway complications occurred in 5 patients but were amenable to laser therapy and stenting. We conclude that double-lung transplantation is an acceptable modality for the treatment of cystic fibrosis patients with end-stage lung disease. It may be a better alternative to heart-lung transplantation considering the paucity of thoracic organ donors.
Flora's Z statistic and standardized mortality ratios (SMRs) as indicators of excess mortality were calculated for a sample of 355 patients with major trauma. A statistically significant overall excess mortality was observed in this sample (Z = 6.77, SMR = 1.81, p less than 0.05). Advanced life support provided by physicians at the scene (MD-ALS) was not associated with reduced excess mortality. A significant trend toward lower excess mortality was associated with a higher level of trauma care at the receiving hospital (p less than 0.05). Total prehospital time over 60 minutes was associated with a significant increase in excess mortality (p less than 0.001). These results support regionalization of trauma care and failed to show any benefit associated with MD-ALS.
The evolution of methods for airway control has been an important factor in improving overall trauma care. Many important advances have been made in technique, tubes, and timing. Current methods of airway control are listed in Table 2 and are categorized as emergency or elective. It is always assumed that basic life support techniques will be in place before this hierarchic scheme for airway control is used. Unfortunately, hypoxemia continues to be a factor in preventable trauma deaths. There is much to be done in the future to further improve airway management in injured patients. There is an immediate need to assess methods of airway control in the pre-hospital phase using a randomized clinical trial. The ideal tube for cricothyroidotomy, tracheostomy, or endotracheal intubation remains to be designed. There is a need for further multicenter trials on the timing of tracheostomy in the critical care unit. The role of differential ventilators in the management of unilateral pulmonary parenchymal injury requires clinical validation. Intravascular membrane oxygenators have been proposed in advanced pulmonary insufficiency in a ventilated patient. Thus, while many important strides have been made in airway management following trauma, there remain great challenges in addressing the persistent problem of systemic hypoxemia after multiple injuries.
The differentiation of episodes of lung allograft rejection from infection continues to be a problem. Bronchoalveolar lavage (BAL) has recently gained some success in the diagnosis and management of interstitial lung disease. To assess the usefulness of BAL in differentiating between lung allograft rejection and infection, we examined the differences in cellular subsets of BAL and peripheral blood (PBL) samples in a controlled canine model of rejection or pneumonia. Single-lung allotransplants were allowed to undergo rejection by withdrawing immunosuppressive agents (n = 6). In another group of dogs (n = 5), pneumonia was induced by transbronchial injection of Pseudomonas aeruginosa and melted agar followed by bronchial fulguration. Cells obtained from bronchoscopic BAL and PBL samples were labeled with functionally characterized cross-reactive murine monoclonal antibodies. Transthoracic needle biopsies and transbronchial biopsies were done to assess their adequacy in examining the rejecting or infected lungs and were compared with open lung biopsies. We found the following: (1) the percentage of DT2-labeled cells was significantly higher (p less than 0.05) in BAL samples from rejecting lungs compared with infected lungs; (2) the PBL/BAL ratio of DT2-labeled cell percentages was significantly higher in pneumonia (1.7 +/- 0.3) than rejection (0.5 +/- 0.2) (p less than 0.004); (3) the percentage of E11-labeled cells in PBL samples was significantly higher (p less than 0.02) in rejection than in infection; and (4) the ratio of WIG4 to DT2 cellular subset percentages in BAL samples from rejection (26.8 +/- 9.9) was significantly lower than from infection (61.0 +/- 22.9) (p less than 0.03). Transthoracic and transbronchial biopsies did not always yield representative specimens.(ABSTRACT TRUNCATED AT 250 WORDS)