PubMed Health⌕ Search

Biomedical subjects

R M Bolman

Publications and source records attributed to R M Bolman.

At least 145 records · Page 8Linked to original sources
PubMed1980

Management of penetrating pancreatic injuries: subtotal pancreatectomy using the auto suture stapler.

Penetrating injuries of the pancreas have been accompanied by significant morbidity and mortality. A technique using the TA-55 Auto Suture Stapler (United States Surgical Corp., Stamford, CT) in patients with pancreatic trauma has been developed and employed clinically. The technical aspects of this simplified technique and its role in the prevention of postoperative complications of pancreatectomy are reviewed. This approach supports an aggressive and complete surgical evaluation of pancreatic injuries.

Adult↗
PubMed1977

Stimulation of gastrin secretion in the pig by parathyroid hormone and its inhibition by thyrocalcitonin.

Gastrin secretion was studied in 16 young anesthetized pigs weighing 14-26 kg. Test substances were infused (0.1 ml/min x 10-20 min) directly into the gastric antrum via a catheter in the right gastroepiploic artery. Samples were collected from a catheter in the right gastroepiploic vein and plasma gastrin was measured by radiommunoassay. The following results were observed: 1) basal gastrin in antral venous blood was 10-5 times that in peripheral blood (620+/-222 pg/ml vs. 41+/-10 pg/ml, 2) native bovine parathyroid hormone (PTH) and synthetic human 1-34 PTH (0.02-4U/min) produced rapid (within 10-30 min) and pronounced (approximately 10-fold) increases in gastrin release with no increase in plasma calcium and, in several animals, in the face of a falling plasma calcium concentration, 3) neither acute thyroidectomy nor infusion of porcine thyrocalcitonin (TCT), 0.5-2.5 U/min) consistently altered basal gastrin secretion (N=3-6), and 4) infusion of TCT (0.5 U/min)along with PTH (2U/min) significantly suppressed the 10-11-fold increase in gastrin release observed when PTH subsequently was infused alone in each pig (N=6). The results demonstrate that PTH can stimulate gastrin secretion in the pig and that TCT can suppress this effect.

Animals↗
PubMed1975

Atypical adrenal insufficiency with failure of the pituitary feedback receptor. A case with associated diabetes mellitus and selective IgA deficiency with steatorrhea.

A 59 year old woman with insulin-dependent diabetes mellitus and chronic diarrhea was found to have mild steatorrhea, selective plasma IgA deficiency and adrenal insufficiency. Significant adrenal secretion of corticosteroids resulted only after prolonged stimulation with large doses of exogenous ACTH. Plasma ACTH levels were not elevated during clinical adrenal insufficiency or after metyrapone administration but did respond normally to vasopressin and insulin-induced hypoglycemia. These studies were interpreted as showing both primary adrenal insufficiency and impaired pituitary reserve for ACTH secretion in response to the feedback stimulus. No deficiency was found in secretion of other pituitary tropic hormones. Jejunal biopsy showed a lack of IgA-containing plasma cells. With cortisone replacement, diarrhea subsided and a malabsorption pattern on a film of the small bowel was no longer seen. IgA deficiency has been noted frequently with steatorrhea but rarely with diabetes and only once previously with adrenal insufficiency.

17-Hydroxycorticosteroids↗
PubMedDate not supplied

Extracorporeal membrane oxygenation after lung or heart-lung transplantation.

Extracorporeal membrane oxygenation (ECMO) has proven to be life-saving in cases of reversible lung injury. One potential application of ECMO in the field of lung transplantation is the support of the patient with acute pulmonary failure immediately after transplantation until the transplanted lung has resumed satisfactory gas transfer function. The authors have had experience with ECMO in three patients who have had acute pulmonary failure and inadequate oxygenation after bilateral single lung (BSLT) or heart-lung transplantation (HLT). Patient 1 is a 47-year-old woman with alpha-1 antitrypsin deficiency who underwent a HLT and experienced fulminant pulmonary edema secondary to an intraoperative coagulopathy that required massive transfusion. Patient 2 was a 45-year-old man with a patent ductus arteriosus (PDA) that resulted in Eisenmenger's complex. Patient 2 underwent an HLT and experienced acute pulmonary failure. Patient 3 is a 58-year-old woman with an atrial septal defect (ASD) and pulmonary hypertension who underwent repair of the ASD and BSLT. Patient 3 experienced complete atelectatic collapse of the right lung and pulmonary edema of the left lung. These three patients had PO2 measurements of 23, 39, and 23 mmHg, respectively, despite receiving 100% FiO2 and maximal ventilatory support. All three patients were subsequently placed on ECMO and had improvement of their oxygenation. Patients 1 and 3 were successfully weaned from ECMO and extubated on post-operative day (POD) 21 and 16, respectively. Patient 2 had significant improvement in oxygenation but died on POD 4 of persistent mediastinal hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Loss, Surgical↗
PubMedDate not supplied

A model of unilateral pulmonary lobar transplantation.

Unilateral lung transplantation has become an accepted treatment for patients with end-stage pulmonary disease. Donor shortage, however, is a major limitation, with up to 87% of patients dying of their pulmonary disease while awaiting transplantation. This is especially true in neonatal and pediatric patient populations. The use of organ segments from cadaveric or living donors may provide a solution. The purpose of this study, therefore, was to evaluate the function and hemodynamic response to pulmonary lobar transplantation using a swine model. Five transplants were performed for acute study, while 10 were performed for 6-week survival. The left lower lobe was harvested from a 70- to 75-kg donor animal. The lobe was then transplanted into a 20 to 25-kg recipient following left pneumonectomy. Graft function was determined by pulmonary arterial and venous blood gas analysis. Cardiac output, pulmonary pressure, and pulmonary vascular resistance were measured under two experimental conditions: (1) baseline and (2) with the right pulmonary artery occluded, forcing the entire cardiac output through the lobar graft. All grafts showed excellent acute and long-term function with regard to gas exchange. The lobar grafts, however, were characterized by high pulmonary vascular resistance both acutely and 6 weeks post-transplant. Contralateral pulmonary artery occlusion resulted in hemodynamic instability and right heart failure. No animal was able to be solely supported by the lobar transplant for more than one hour. These results have prompted a bilateral lobar transplant model and current studies are in progress.

Animals↗
PubMedDate not supplied

The role of electrolyte in lesion size using an irrigated radiofrequency electrode.

Multiple attempts have been made to eliminate atrial fibrillation by performing the surgical maze procedure with radiofrequency energy. Currently, this is limited because of the risk of atrial perforation and the lack of transmural penetration. Saline irrigation has been investigated as a method of radiofrequency cautery tip cooling to prevent rapid temperature and impedance rises, which have been shown to lead to perforation or decreased radiofrequency penetration after eschar formation. There are few data on the influence that different types of electrolyte irrigation solutions have on lesion depth. Using a novel hollow cautery pen, we infused either an electrolyte solution (0.9%, 3%, 14.6%, or 23.4% sodium chloride), a nonelectrolyte solution (1.5% glycine), or no irrigation to produce 819 lesions on 14 left ventricles in swine using radiofrequency energy (450+/-10 kHz) applied at two output settings (20 and 75 watts). The nonelectrolyte solution increased lesion depth compared with no infusion at 20 watts but produced shallower lesion depths compared with electrolyte solutions at 75 watts. Compared with the other electrolyte solutions, the 0.9% sodium chloride solution produced the deepest lesions (3.34+/-0.06 mm) at 75 watts (p < 0.001). As the concentration of electrolyte increased, lesion depth decreased unless generator output increased. Formation of eschar and tissue destruction was seen in the noninfusion and nonelectrolyte groups but not in the electrolyte group. A conductive media coupled with radiofrequency energy allowed for greater lesion depth than irrigated cooling with a nonelectrolyte solution or no irrigation. There was an inverse relationship between electrolyte concentration and lesion depth. We conclude that the concentration of electrolyte irrigant is an important consideration when choosing a solution to improve transmural penetration and decrease the risk of tissue destruction from radiofrequency energy.

Animals↗
PubMedDate not supplied

Chronic evaluation of orthotopically implanted bileaflet mechanical aortic valves in adult domestic sheep.

This study was intended to develop a technically feasible and reproducible model for chronic hemodynamic and mechanical evaluation of orthotopically implanted bileaflet mechanical aortic valves in adult domestic sheep. Three adult sheep (mean age 22 weeks, mean weight 76 kg) underwent aortic valve replacement using 19-mm bileaflet aortic valves. Standard cardiopulmonary bypass techniques were followed, including mild hemodilution, systemic hypothermia, and cardioplegic arrest. After performing a left fourth intercostal thoracotomy, the valves were placed using interrupted 3-0 Ticron (Davis + Geck) inverted mattress sutures through a transverse aortotomy. The average cardiopulmonary bypass time was 58+/-1 min. No chronic anticoagulation was used. There were no surgical complications. All three animals (100%) remained clinically well until elective sacrifice after postoperative day 150. The average cardiac output for the animals at sacrifice was 3.8+/-1.0 L/min. The mean aortic ejection velocity was 304.7+/-47.3 cm/s and the mean pressure gradient was 24.6+/-6.7 mm Hg. There was no clinically significant thrombus formation or paravalvular leaks. Thus, we have demonstrated that it is technically feasible to orthotopically implant mechanical aortic valves in sheep. There are several features that contribute to the success of this model, including use of a transverse aortotomy, adequate de-airing, and the use of mild hemodilution during bypass. We believe that this model is reproducible and can be used to study other valve designs. In addition, this model allows for site-specific preclinical assessment of new or modified mechanical heart valves.

Animals↗
PubMedDate not supplied

Long-term evaluation of orthotopically implanted stentless bioprosthetic aortic valves in juvenile sheep.

The aim of this study was to develop a technically feasible and reproducible model for chronic evaluation of stentless bioprosthetic aortic valves implanted orthotopically using juvenile domestic sheep. This report summarizes the results of a study conducted to assess orthotopically placed 19-mm stentless aortic bioprosthetic valves. Twenty-seven juvenile sheep underwent aortic valve replacement. Standard cardiopulmonary bypass techniques were followed. The average cardiopulmonary bypass time was 73 min. No chronic anticoagulation was used. There were two deaths (7%) due to surgical complications. In the remaining 25 experiments, 11 animals (41%) died prior to the scheduled sacrifice on postoperative day 150. One early death occurred due to coccidiomycosis infection, one due to technical error, one due to pulmonary embolus, four due to prosthetic annular size disproportion, and four due to thrombi. The remaining 14 animals (52%) underwent left and right heart catheterization, angiography, echocardiography, and sacrifice after postoperative day 150. The average weight of the sheep at elective sacrifice was 60 kg (mean weight gain 12.5 kg). The average cardiac output for the sacrificed animals was 5.1 L/min. The mean velocity of blood across the aortic valve for the sacrificed animals was 317 cm/s and the mean pressure gradient was 26.2 mm Hg. Two features suggest that this model may have broad application. First, we have demonstrated that it is technically feasible to evaluate orthotopically placed stentless bioprosthetic aortic valves in growing sheep. Second, the aortic root size of the juvenile sheep allows for implantation and evaluation of a human size aortic valve (19 mm). We believe that this model is reproducible and can be used to study stentless valve designs.

Animals↗