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Biomedical subjects

R L Varco

Publications and source records attributed to R L Varco.

At least 73 records · Page 4Linked to original sources
PubMed1977

The nature of failure of pulmonary adaptation to atelectasis.

The ability of the lung to decrease blood flow to an atelectatic lobe and to increase flow to normal after reinflation was investigated with a model using left lower lobe atelectasis (LLLA) in the dog. The change in the shunt fraction QS/Qt with continuing LLLA was assumed to represent a change in blood flow to the LLL. With LLLA the Qs/Qt rose from 0.112 to 0.172 and then decreased to 0.119 by the end of 2 hours at the rate of -17%/hour. Reversal of atelectasis for varying times demonstrated that the pulmonary vasoconstrictive response persisted for at least 4 hours after reinflation of LLLA. With LLL ischemia for 1 and 2 hours followed by LLLA, Qs/Qt decreased, but at a rate less than the controls, whereas after hemorrhagic shock with venous reinfusion and LLLA, the Qs/Qt did not decrease. When hemorrhagic shock was followed by arterial reinfusion, 60% had a normal response to LLLA; 40% did not. There was no difference in PVR in these two groups. Pulmonary extravascular water in both groups was the same as in controls. Infusion of NE after 3 hours of LLLA caused Qs/Qt to rise from 0.125 to 0.248, comparable to the value immediately after onset of LLLA. EPi had similar results. Catecholamines may restore blood flow to the atelectatic lobe by causing a maximum generalized pulmonary vasocontriction or by overexpansion of the pulmonary blood volume secondary to peripheral vasoconstriction and thereby abolish any differential in pulmonary vascular resistance across the lung. The early hypoxemia of adult respiratory distress syndrome may arise not on the basis of any intrinsic lung pathology but rather as the result of a normal response of the lung to increased catecholamines.

Animals↗
PubMed1976

Rapid long tube intubation of the jejunum by a new endoscopic device.

Despite the advantages of aseptic nonoperative intubation of the small intestine for decompression of obstructed loops, 48% of the attempts lead to failure to pass the tube through the pylorus. The difficulty and inconvenience of passage beyond the stomach have been overcome by the development of a special tube attachment adapted to a fiberoptic duodenoscope (Olympus Model GIF-K). Under direct endoscopic vision the tube can be carried into the second and third portion of the duodenum, released from the scope, and then further prodded into the jejunum. The entire procedure takes less than 15 minutes. Rapid intubation has now been easily carried out in five patients. Three patients had mechanical bowel obstruction. Rapid and effective decompression allowed adequate time for stabilization of concomitant serious problems such as (1) marked cardiopulmonary dysfunction secondary to a near fatal pulmonary embolus, (2) severe peritonitis post appendectomy, and (3) acidosis and dehydration. Surgical correction of the obstructing lesions was safely deferred for up to one week until the concomitant problems improved. The fourth patient, who was a renal transplant recipient, had chronic gastric ileus secondary to duodenal ulcer. Rapid passage of the long tube into the jejunum allowed restoration of nutrition and avoidance of gastrostomy. The fifth patient, with an ileus secondary to an infected abdominal aortic graft, underwent successful decompression but died of sepsis. He represents the only mortality. We propose that jejunal intubation using our technic is not only rapid but relatively easy and should encourage the wider acceptance of aseptic long tube intestinal decompression.

Adult↗
PubMed1976

Palliation of infants with truncus arteriosus through creation of a pulmonary artery ostial stenosis.

A surgical procedure for palliation of infants with truncus arteriosus and excessive pulmonary blood flow (types I, II, and III) is described. The technique involves the production of ostial stenosis of the pulmonary artery from within the truncus using cardiopulmonary bypass. This method has advantages over pulmonary artery banding, which in general has produced disappointing results.

Constriction↗
PubMed1976

Treatment of heterozygous type II hyperlipidemia by partial ileal bypass in a pediatric population.

Nine patients underwent partial ileal bypass as management for heterozygous type II hyperlipidemia. The average age of this group was 12.5 yr. Follow-up has ranged from 1 to 6 yr. The growth and development of these children proceeded normally. The overall average serum cholesterol reduction was 33% when compared to the preoperative but postdietary control value. Side effects of the procedure include transient diarrhea and inability to absorb vitamin B12, requiring periodic parenteral administration. Partial ileal bypass has been shown to be an effective and obligatory method of treatment of hypercholesterolemia in children.

Adolescent↗
PubMed1976

Anomalous double blood supply to the lung.

We report an unusual case in which an apparently normal upper lobe of the right lung was supplied by major systemic arterial and pulmonary arterial vessels. The anomalous artery arose from the descending aorta. Following interruption of this vessel, the machinery-like murmur previously present disappeared.

Child, Preschool↗
PubMed1976

The effect of portacaval shunt on plasma lipids and tissue cholesterol synthesis in the dog.

Portacaval shunt (PCS) has been proposed as a therapy for hyperlipidemia; however, its lipid-lowering mechanism is unknown. In this study PCS was performed on ten mongrel dogs to measure its effect on plasma lipids and on the cholesterol synthesizing ability of the liver and intestines, the major indodenous cholesterol synthesizing tissues. Plasma was analyzed for total cholesterol (CHOL), triglycerides (TG), and the CHOL content of three plasma lipoprotein fractions. Jejunal, ileal, and hepatic cholesterol synthetic rates were determined by 14C-acetate incorporation to CHOL in tissue slices obtained at operation before PCS and 44 +/- 4.1 (S.D.) days after PCS. Plasma CHOL decreased by 18 +/- 7 (S.E.), 34 +/- 8 (S.E.), and 57 +/- 14 (S.E.) mg. per 100 ml. by 4, 6, and 16 weeks after PCS, respectively. TG decreased by 13 +/- 5 (S.E.), 27 +/- 5 (S.E.), and 30 +/- 9 (S.E.) mg. per 100 ml. at corresponding time intervals. Paired Student's test analysis of CHOL and TG changes are significant at the p less than 0.05 level. CHOL content of the three plasma lipoprotein fractions decreased correspondingly. Intestinal tissue CHOL synthesis rates changed only slightly. Hepatic synthetic rates increased by 30 to 40%; however, no synthetic rate changes were statistically significant at the p less than 0.05 level. PCS is associated with decreased in plasma CHOL [42% (see article)] AND TG [53% (see article)] in dogs up to 16 weeks following operation. Statistically significant changes in endogenous CHOL synthesis were not demonstrated by this study. The mechanism by which PCS affects plasma lipids in the dog is unknown as yet.

Animals↗
PubMed1976

Aberrant left pulmonary artery presenting as a right paratracheal mass in an adult.

Aberrant left pulmonary artery, or pulmonary sling, is a rare variation of the pulmonary vasculature, with only one previous report of the condition being recognized in an adult. In this report a second case recognized de novo in an adult is presented. Both of these adults were evaluated because of right paratracheal masses which required differentiation from pulmonary malignancies. The barium swallow shows a characteristic indentation of the anterior esophageal wall and the lateral tomogram demonstrates absence of the left pulmonary artery from its normal position in the left hilum. The pulmonary arteriogram is diagnostic and allows avoidance of more invasive diagnostic measures.

Airway Obstruction↗
PubMed1975

Gastric secretion and serum gastrin in human small bowel bypass.

Jejunolieal bypass (JIB) patients provide a unique opportunity to study the relationship between small bowel loss and gastric secretory function. Preoperatively, and approximately one year postoperatively, measurements of gastric secretion were taken in 37 patients who underwent JIB for massive obesity. Basal acid output increased by 0.52 plus or minus 0.35 mEq/hr (P greater than.2), and peak stimulated acid output increased by 1.99 plus or minus 0.96 mEq/30 min (P smaller than .05). A separate group of 26 postoperative and 17 preoperative (control) JIB patients had fasting serum gastrin levels measured by radioimmunoassay. Postoperative patients had levels of 37 plus or minus 5 pg/ml, and control patients had levels of 36 plus or minus 4 pg/ml (P greater than .5). We conclude that following JIB for obesity, there is no significant change in basal acid secretion or in serum gastrin. There is a small, but statistically significant, increase in peak stimulated acid output. We currently find no clinical correlation with this change.

Fasting↗
PubMed1975

The partial ileal bypass operation in treatment of the hyperlipidemias.

Partial ileal bypass is, today, the single most effective means available for lowering the plasma lipids, in particular the plasma cholesterol concentration. The cholesterol lowering effect of this procedure is universally lasting; response escape or rebound of lipid levels has not occurred. The operation is safe. In addition, the obligatory benefits of this mode of therapy make it attractive as a therapeutic alternative, especially in a young and asymptomatic population. We do not advocate this operation as the treatment of choice for all hyperlipidemic individuals. It may be the treatment of choice for certain patients with hyperlipidemia.

Cholesterol↗
PubMed1975

Operative repair of atrial septal defect without cardiac catheterization.

Thirty-three children with secundum or sinus venosus atrial septal defects underwent operative correction at the University of Minnesota Hospitals between January, 1972, and December, 1973. Nineteen of these patients (58%) did not have cardiac catheterization as part of their preoperative evaluation, since clinical assessment of the child, with or without corroborative evidence obtained by echocardiography and radionuclide angiocardiography, provided sufficient information to permit recommendation of operation. In the majority of patients with uncomplicated atrial septal defect, cardiac catheterization is not a necessary part of the preoperative evaluation and may be reserved for those patients with unusual clinical or laboratory features.

Adolescent↗