Surgery
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Hepatic dysfunction after portacaval shunting (PCS) has been attributed to loss of portal perfusion to the liver. Proponents of selective systemic shunting state that reduced encephalopathy and hepatic dysfunction with this procedure result from the maintenance of portal perfusion to the liver through the hypertensive mesenteric venous circulation. We questioned the importance of maintaining the diminished portal flow to the cirrhotic liver because hepatofugal flow is known to develop in many of these patients. ⋯ Hepatic arterial flow 6 weeks after PCS with MVH was associated with lower blood ammonia and improved hepatocellular function compared with animals with PCS alone. These results support the hypothesis that MVH is important in maintaining blood supply--beyond providing driving force for sustained portal flow to the liver. This is an important consideration in the medical and surgical management of portal hypertension, a condition in which profound reduction in portal pressure may negatively affect compensatory hepatic arterial blood flow.
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Although adequate tissue oxygenation is essential to maintain cellular metabolism, the use of hyperoxia to improve oxygen delivery or to improve metabolic performance is controversial. For example, supplemental inspired oxygen is reportedly beneficial in the treatment of some experimental infections; however, oxygen therapy also has well-documented adverse side effects. To evaluate the effect of increased inspired oxygen concentration (FIO2) in animals with fulminant sepsis, 117 Sprague-Dawley rats underwent cecal ligation and puncture. ⋯ Arterial blood gases documented maintenance of oxygenation and ventilation. Thus, pulmonary oxygen toxicity does not appear to be the mechanism for increased mortality. Supplemental oxygen may worsen, rather than improve, survival after fulminant infection.
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Many of the alterations in lung function that occur after upper abdominal surgery are attributable to reduced diaphragmatic activity. This study was undertaken to determine whether incentive spirometry produces a voluntary activation of diaphragmatic movement in patients with postoperative diaphragmatic dysfunction. Inductance plethysmography was used to measure the tidal volumes of the abdomen and chest in eight women before cholecystectomy and on the first and third postoperative days. ⋯ Preoperatively, incentive spirometry increased the tidal volume of the abdominal compartment from 141 +/- 26 ml to 285 +/- 188 ml (p less than 0.005) as a result of increased diaphragmatic movement. This effect was not seen postoperatively; instead, postoperative patients responded to incentive spirometry by increasing the tidal excursion of the chest compartment (158 +/- 37 to 630 +/- 253, p less than 0.005), without any increase in abdominal tidal volume. Thus, incentive spirometry failed to increase diaphragmatic movement in postoperative patients.
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The effect of wood smoke inhalation (SI) on pulmonary vascular permeability was studied in open-chested, anesthetized dogs. Animals were divided into two groups. A prenodal lymphatic vessel was cannulated in group I (n = 7), and baseline (BL) lung lymph flow (QL) and lymph (CL) and plasma (CP) protein concentrations were measured. ⋯ In group II (n = 15) total protein concentration of airway fluid was compared with that of plasma after smoke inhalation, intravenous alloxan, and increased Pla. The ratio of protein concentration in airway fluid to plasma after SI (0.70 +/- 0.07) was greater than that obtained with increased Pla (0.64 +/- 0.07) but less than that after alloxan (0.85 +/- 0.04). These data indicate that SI in the dog results in a moderate increase in pulmonary vascular permeability that is less severe than that induced by alloxan.
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Outcome of 56 patients who underwent horizontal gastroplasty (HGP) and 126 who underwent Roux-en-Y gastric bypass (RYGB) was assessed at 18 months postoperatively according to three definitions of successful weight loss; also, outcome was evaluated in the context of amelioration of obesity-related medical problems. Outcome definitions included the following: I, loss of 25% or more of preoperative weight; II, loss of 50% or more of excess weight; III, loss to within 50% of ideal body weight. To evaluate the impact of preoperative weight on success rate, patients were divided into two weight groups: "morbidily" obese patients, who were 100 to 199 pounds overweight (n = 146), and "super"-obese patients who were 200 pounds or more overweight (n = 36). ⋯ Although super-obese patients lost more pounds than the lighter morbidly obese patients, a significantly lower number of super-obese patients lost within 50% of ideal weight. Super-obese patients must lose more weight to reduce their actuarial risk. These results show that the definition of successful outcome may significantly influence the overall success rate in a large series of bariatric surgical patients.