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Biomedical subjects

C Dennis

Publications and source records attributed to C Dennis.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Helping students use nursing models to guide research.

This article describes a teaching-learning strategy that was used to help third-year undergraduate BSN students understand the importance of situating nursing research questions within a nursing theoretical framework. Examples of student-generated research questions and their transformation into questions that reflect explicit nursing frameworks are provided. Common difficulties encountered by the students are also discussed.

Education, Nursing, Baccalaureate↗
PubMedDate not supplied

Airway stenoses after lung transplantation: management with expanding metal stents.

Success in lung transplantation has been hindered by airway complications, usually as a result of anastomotic ischemia and stenosis. We report our experience with expanding metal stents in managing airway stenoses after lung transplantation. From April 1984 through November 1993, 46 single lung, 5 double lung, and 154 heart-lung transplantations were performed at Papworth Hospital. All patients received immunosuppression with azathioprine, cyclosporine, methylprednisolone, and induction antithymocyte globulin. Fourteen patients (nine single lung, two double lung, and three heart-lung) had an airway stenosis requiring a stent. The most common features were shortness of breath, wheezing or stridor, and a fall in pulmonary function tests (11 patients). Three patients had pneumonia. Airway stenosis was diagnosed on bronchoscopy an average of 61 days after transplantation (range 3 to 245 days). Stent placement occurred an average of 18 days after the diagnosis (range 2 to 84 days). One heart-lung transplant recipient received a silicone rubber stent. All other patients received expanding metal stents. Six patients required multiple stent placements. After stent placement the average increase in the forced expiratory volume in 1 second was 117%. Infection complicated the stenoses in 12 patients. Pseudomonas aeruginosa and Aspergillus fumigatus were the most common pathogens, each occurring in six cases. Multiple pathogens were isolated in seven cases. Three patients died as a direct consequence of their airway problems. Two died of pneumonia despite stenting, and a third died of acute occlusion of the silicone rubber stent. Expanding metal stents are an effective treatment of airway stenoses in lung transplant recipients. Patients with suspected airway problems should be referred for early bronchoscopy with the potential for stent placement.

Adult↗
PubMedDate not supplied

The evolution of counterpulsation techniques.

Assisted circulation techniques are an outgrowth of extracorporeal pump oxygenator systems developed in the mid 1950s. But the differences in physiology of total perfusions and of parital perfusions for assisting circulation delayed the clinical application of the intra-aortic balloon. The problems and risks in providing circulation assistance and the approaches used to overcome them are discussed. The various counterpulsation techniques are described and data presented to demonstrate the increased survival in patients with myocardial infarction and cardiogenic shock.

Assisted Circulation↗
PubMedDate not supplied

Who waits longest for heart and lung transplantation?

Between August 1982 and December 1992, 260 patients were accepted for heart and lung transplantation, of whom 139 patients underwent transplant surgery. One hundred twenty-one patients have not received transplants, of whom 80 have died, four were transferred to other lists, and 37 were still waiting for suitable organs at the close of the study. Median waiting time for those patients who underwent heart and lung transplantation was 7 months, whereas patients who died waiting spent a median of 5 months on the list. Recipients are matched to donor organs according to blood type, size (total lung capacity), and cytomegalovirus antibody status. These factors, along with age, gender, underlying diagnosis, and Toxoplasma antibody status, were studied to assess their influence on survival after acceptance and time to transplantation. The only characteristic that significantly influenced survival after acceptance was the underlying disease, with patients with Eisenmenger's syndrome having significantly longer survival than the other groups (relative risk = 0.21; p < 0.001). Patients with Eisenmenger's syndrome underwent transplantation at a slower rate than did other patients (relative risk = 0.51; p = 0.012). Patients who had a total lung capacity of more than 6 L underwent transplantation significantly more quickly than did smaller patients (relative risk = 1.98; p = 0.005). Male patients underwent heart and lung transplantation at a quicker rate than did female patients (relative risk = 1.86; p < 0.001), although this was related to size. Patients who had cytomegalovirus-positive antibodies underwent transplantation at almost twice the rate of patients who had cytomegalovirus-negative antibodies (relative risk = 1.92; p < 0.001). Age at acceptance, blood type, and Toxoplasma status did not significantly influence time to heart and lung transplantation. In summary, cytomegalovirus antibody status, patient size, and gender significantly affect the waiting time to heart and lung transplantation. Patients with Eisenmenger's syndrome wait longer than other patients as a result of the natural history of their disease.

Adolescent↗
PubMedDate not supplied

Domino heart transplantation: the Papworth experience.

The use of donor hearts from heart-lung recipients, the so-called domino procedure, began at Papworth Hospital in November 1988. Between then and September 1992, 198 heart transplantations and 86 heart-lung transplantations were performed. Fifty-three heart-lung recipients donated their hearts for use in the domino procedure. Thirty-two domino hearts were transplanted at Papworth and 21 were exported to other centers. Institution of the domino procedure allowed us to perform 19% more heart transplantations (166 to 198) than would have been done had the procedure not been used. The ischemic time was significantly shorter for the domino hearts compared with organs from brain dead donors (134 minutes versus 191 minutes; p < 0.001). No difference was found in the 3-month (84% versus 83%) or 1-year (74% versus 76%) survival between domino and nondomino recipients. Other potential advantages of the domino procedure include detailed pretransplantation evaluation of the heart in live donors and the potential for human leukocyte antigen matching. Additionally many heart-lung recipients have elevated pulmonary artery pressures and a "conditioned", hypertrophied right ventricle. The use of such hearts for heart transplantation has theoretic appeal for patients with elevated pulmonary vascular resistance.

Actuarial Analysis↗