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Biomedical subjects

J W Lea

Publications and source records attributed to J W Lea.

7 recordsLinked to original sources

Videothoracoscopy: improved technique and expanded indications.

Current videoendoscopic technology and percutaneous techniques of exposure and dissection have been successfully applied to abdominal surgery with favorable results. Application of this technology to our practice of thoracoscopy is the basis of this report. Videothoracoscopy has been performed in 39 patients for the following indications: chronic pleural effusion, interstitial lung disease, mediastinal lymphadenopathy in lung cancer, persistent air leak after decortication, mediastinal mass, recurrent spontaneous pneumothorax, hydropneumothorax with persistent air leak, and pleural-based mass. The technique we employ includes lateral decubitus positioning and double-lumen endotracheal intubation with ipsilateral lung collapse. The videoscope, retractors, and instruments are introduced through separate 10-mm incisions. Percutaneous manipulation of instruments and the videoscope is guided by images produced on television screens without dissection, and if resection is performed, the incision is enlarged to allow specimen retrieval. Procedures performed using this technique include pleural biopsy, partial pleurectomy, lysis of adhesions, lung biopsies, staging lymph node biopsy, lung nodule biopsy, pleural-based mass resection, and mediastinal mass biopsy and resection. This videoendoscopic technique greatly improves visualization of thoracic anatomy, facilitating thoracoscopy and enhancing exploration of the chest. It is preferred over conventional thoracoscopy and, in some patients, reduces the magnitude of operation by avoiding thoracotomy.

Adult

Internal mammary artery graft at reoperation: risks, benefits, and methods of preservation.

To determine the effect of a prior internal mammary artery (IMA) graft on coronary artery bypass reoperation (CABR), we reviewed our experience with 410 consecutive patients: 313 received only saphenous vein grafts at initial coronary artery bypass grafting (CABG), and 97 received at least one IMA graft at CABG. Cardiac catheterization data before CABG were available in 110 patients (56 received only saphenous vein grafts, 54 received at least one IMA graft), allowing comparison of left ventricular function at CABG and CABR. Injury of the IMA graft occurred in 5 patients (1 death), but presence of an IMA graft was not an independent predictor of morbidity or mortality. Overall, the incidences of complications and deaths were higher in patients with saphenous vein grafts than in patients with IMA grafts, though not significantly so. Internal mammary artery grafts better preserved cardiac function: patients with IMA grafts had worse left ventricular function before CABG but better left ventricular function before CABR than patients with saphenous vein grafts. Left ventricular function deterioration from before CABG to before CABR was significantly less in patients with IMA grafts. We conclude that the risk of CABR is not increased by a previously constructed IMA graft and that left ventricular function is better preserved at CABR when an IMA graft was constructed at the initial operation.

Confounding Factors, Epidemiologic

Emergency coronary bypass not associated with preoperative cardiogenic shock in failed angioplasty, after thrombolysis, and for acute myocardial infarction.

We have reviewed the literature and supplemented it with our own experience to provide a current viewpoint on emergency coronary bypass in three settings in which cardiogenic shock did not exist preoperatively. Acute failure of coronary angioplasty led to emergency operation in 701 patients with 25 (3.6%) deaths. There was a 37.6% incidence of perioperative infarction. Thrombolytic therapy for acute myocardial infarction, sometimes followed by angioplasty, led to emergency operation within 8 hours in 145 instances with four (2.1%) deaths. Emergency coronary bypass was primary therapy for 1,051 patients with acute myocardial infarction with 51 (4.9%) hospital deaths. Emergency operation for failed angioplasty is frequently mandated in the setting of surgical standby and iatrogenic ischemia although some operations could be postponed to an elective status. Emergency operation after thrombolytic therapy has been used for unsuccessful angioplasty of the infarct vessel, left main stenosis of greater than 50%, left main equivalent, multivessel disease with complex lesions not amenable to angioplasty, or failure to restore patency of the infarct vessel with thrombolysis. Operation within 12 hours of thrombolytic therapy is associated with a coagulopathy causing increased bleeding, the need for transfusion, and a greater incidence of reoperation for perioperative bleeding.

Angioplasty, Balloon

Efficacy of cefazolin, cefamandole, and gentamicin as prophylactic agents in cardiac surgery. Results of a prospective, randomized, double-blind trial in 1030 patients.

In an effort to develop an improved regimen of antibiotic prophylaxis in cardiac surgery, 1030 patients who were to have elective cardiothoracic surgery involving a median sternotomy were selected at random to receive cefamandole or cefazolin, with or without gentamicin, in a prospective double-blind study. Cefazolin was significantly less effective than cefamandole at both the sternal (1.8% vs. 0.4%, respectively, p less than 0.05) and donor sites (1.3% vs. 0%, respectively, p less than 0.02). Seven Staphylococcus aureus infections occurred among cefazolin recipients as compared with no such infections among the patients receiving cefamandole (p less than 0.01). All five wound infections yielding fungi or gentamicin-resistant gram-negative rods occurred in patients who had received gentamicin as a second prophylactic agent. These data suggest that gentamicin has no role as a prophylactic antibiotic in cardiac surgery and that, compared with cefamandole, cefazolin offers unreliable prophylaxis against deep infection at both the sternal and donor sites.

Cardiac Surgical Procedures

Internal mammary artery grafts: technical factors influencing patency.

Eight hundred fourteen patients with internal mammary artery (IMA) coronary artery bypass grafts have been restudied 961 times with coronary arteriography, primarily to evaluate the patency of the grafts in the setting of symptomatic coronary occlusive disease. Their records were reviewed to assess graft patency as related to the technical aspects of coronary artery bypass surgery. Patency was evaluated using life-table analysis of the data. The method of harvesting the IMA played no role in patency. The left anterior descending coronary artery was the recipient coronary artery with the highest patency rate. The left IMA had a significantly higher patency rate than the right IMA. As a group, the IMAs had a significantly higher patency rate than saphenous vein grafts. However, there was no difference between right IMA grafts and saphenous vein grafts. The mammary artery grafts that remained patent throughout the study had a significantly higher blood flow after bypass than did those that became occluded (43.0 +/- 0.9 versus 28.9 +/- 1.8 ml/min; p less than .001).

Blood Flow Velocity

A self-instructional approach to imagery training for medical students.

At the University of North Carolina School of Medicine, 110 first-year medical students were randomly assigned to experimental and control groups. Before the experimental group began the academic year, they were trained in visual imagery by means of 4 self-instructional units. Subsequently, both groups were given a criterion test to assess their ability to process and retrieve information. The investigators concluded that visual imagery can be taught and that it may help some medical students.

Association Learning