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C Wahlen

Publications and source records attributed to C Wahlen.

At least 19 recordsLinked to original sources
PubMed1992

[Acquired diverticulosis of the small bowel].

The authors report about their surgical experience? On the basis of one case of pneumascos and one case of gastrointestinal hemorrhage with collapse, for which no origin was found preoperatively and which was attributed to the presence of diverticula in the small bowel. The analysis of the literature shows that this rare condition (0.1% of the population) is mainly expressed as acute complications: diverticulitis, perforation, hemorrhage, obstruction. The treatment is surgical as a rule, but it can be medical if the condition is included in the scope of a malabsorption syndrome.

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PubMed1989

Contribution of peripheral blood pooling to central hemodynamic disturbances during endotoxin insult in intact dogs.

The aim of the present study was to determine possible effects of Escherichia coli endotoxin on peripheral vascular compliance and relate them to concomitant central hemodynamic disturbances. Endotoxin was infused at 0.25 micrograms/kg.min during 2 h in six anesthetized dogs, while six additional animals served as controls. Vascular compliance of the systemic circulation was calculated in intact animals from the changes in CVP after known changes in systemic blood volume. In control dogs, vascular compliance averaged 2.3 ml/mm Hg.kg body weight. During slow endotoxin infusion, cardiovascular effects were measurable only after a certain period of time had elapsed from the start of endotoxin insult and consisted of hypotension associated with systemic vasodilation. Systemic BP decreased gradually from 124 to 68 mm Hg while vascular compliance was finally increased by 100%, when compared to control values. This latter rise was responsible for a reduction in the cardiac preloads. Pulmonary wedge pressure and CVP were decreased from 7.1 to 3.4 and from 4.5 to 2.6 mm Hg, respectively. However, parallel to the decrease in left ventricular preload, endotoxin induced a progressive decrease in left ventricular afterload. Because of the balance in ventricular loading, cardiac output remained almost unchanged. After volume loading (dextran 30 ml/kg), cardiac output was remarkably increased from 3.28 to 6.24 L/min.m2 while peripheral vasodilation was not affected by this maneuver. It is concluded that low dose endotoxin infusion induces in dogs a hemodynamic pattern similar to human sepsis. The left ventricular loading changes are related to an enhanced systemic vascular compliance from 2.3 to 4.5 ml/mm Hg.kg. High flow shock state is encountered provided peripheral blood pooling is compensated by adequate volume replacement.

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PubMed1987

Effects of intravascular volume expansion on lung fluid balance in a canine model of septic shock.

We tested the early effects of endotoxin on both the permeability of capillary membranes and microvascular pressure. One group of dogs (n = 8) were fluid loaded (30 ml/kg dextran-40) after having been subjected to a 2-h Escherichia coli endotoxin infusion (0.25 micrograms/kg X min). A second control group of animals (n = 6) was submitted to a similar (25 ml/kg) volume loading over an equivalent 30-min period. We estimated extravascular lung water (EVLW), calculated the effective pulmonary capillary pressure, and determined the alveolar-capillary filtration coefficient (Kf) after volume loading. Only the septic animals consistently showed elevated EVLW values consistent with pulmonary edema. The results showed, however, that the Kf calculated for the dogs that received endotoxin was no different from that of control group (Kf = 0.005 ml/kg X min X mm Hg). Instead, endotoxin constricted the pulmonary veins which led to a considerable rise in microvascular hydrostatic pressure above the level at which the lungs could not resist edema formation. We conclude that acute pulmonary edema that follows endotoxin insult and subsequent therapeutic volume replacement is due to an increased filtration force instead of an alteration in the microvascular permeability.

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PubMed1987

A comparison of Escherichia coli endotoxin single bolus injection with low-dose endotoxin infusion on pulmonary and systemic vascular changes.

The purpose of this study was to compare effects of single bolus endotoxin injection with sustained low-dose endotoxin infusion on systemic and pulmonary hemodynamics in anesthetized dogs. When administered as a bolus (.01 mg/kg), endotoxin induced systemic vascular changes whose evolution could be divided into two consecutive phases. In the early phase, marked hepatic venoconstriction caused a rise in portal pressure followed by abrupt decreases in both cardiac output and blood pressure. Mean pulmonary artery pressure remained unchanged. Because of lowered blood flow, both peripheral and pulmonary resistances increased. The rise in the latter was due to a prominent vasoconstriction of pulmonary arteries. Following a partial spontaneous recovery from shock, the late phase was characterized by a low-output state combined with high systemic vascular resistances. In contrast, when endotoxin was given at a slow infusion rate (250 ng/kg/min) over a 2-hour period of time, cardiovascular effects were basically different from the preceding ones, and they were measurable only after a certain period of time had elapsed from the start of endotoxin insult. First, blood pressure decreased gradually, while cardiac output remained almost unchanged. Therefore, peripheral resistance was decreased. Second, in the pulmonary circulation, the site of vasoconstriction was shifted from arteries to veins. We conclude that there is a fundamental difference in the response of the dog's systemic and pulmonary circulation as a function of endotoxin administration as either a bolus or slow infusion. This difference might be due to sudden elevated portal pressure responsible for an abrupt cardiovascular collapse in dogs subjected to bolus injection.

Animals↗
PubMed1987

Pulmonary hydrostatic microvascular pressure changes and lung fluid balance during histamine infusion in intact dogs.

The effects of histamine on systemic and pulmonary hemodynamics of dogs were studied in six intact animals. Histamine infusion resulted in an almost immediate, precipitous fall in blood pressure (BP), pulmonary capillary wedge pressure (PCWP), and right atrial pressure (RA) as well as an increase in heart rate. Partial recovery occurred about 5 minutes after infusion was stopped. Cardiac output did not change significantly. Consequently, the calculated peripheral resistance decreased afterwards. Hepatic portal pressure rose significantly after 2 minutes of histamine infusion with partial recovery in about 5 minutes. Suprahepatic venous pressure did not change significantly. Although pulmonary arterial pressure did not necessarily rise, total pulmonary vascular resistance increased in every dog. If the absolute level in pulmonary arterial resistance remained greater (Ra 105 mm Hg/liter-1 min X kg-1) than the level of venous resistance (Rv 70 mm Hg/liter-1 min X kg-1), the relative increase in venous resistance (100%) was higher than the increase in Ra (35%). On the other hand, effective capillary pulmonary pressure remained unchanged. Central blood volume and extravascular lung water increased upon histamine infusion and returned rapidly to baseline when histamine infusion was stopped. No significant changes occurred in either effective pulmonary compliance and arterial blood gas values. Our data lead us to conclude that histamine's major action occurs in the venous pulmonary segments; pulmonary and splanchnic blood pooling is responsible for a fall in cardiac preload; and an increase in extravascular lung water and central blood volume with unchanged effective pulmonary pressure might be explained by an increase in microvascular surface area.

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PubMed1986

Effects of Escherichia coli endotoxin on pulmonary vascular resistance in intact dogs.

The effects of endotoxin on pulmonary hemodynamics were studied in seven intact dogs. The distribution of pulmonary vascular resistance was estimated by the effective pulmonary capillary pressure, which was derived from the pressure transient recorded while the pulmonary artery catheter was rapidly wedged. After the injection of endotoxin, cardiac output and aortic pressure consistently fell. Pulmonary artery occlusion (wedge) pressure also decreased, but not significantly. Although pulmonary artery pressure did not necessarily rise, total pulmonary vascular resistance increased in every dog. The absolute increase in pulmonary artery resistance was greater (142 mm Hg/L X min/kg); than in venous resistance (111 mm Hg/L X min/kg); however, the relative increase in venous resistance was higher (410% for venous resistance vs. 220% for pulmonary artery resistance). As a result of venoconstriction, there was a consistent increase in effective pulmonary capillary pressure (from 2.5 to 6.3 mm Hg). Our data indicate that the pulmonary vascular response to endotoxin injection is characterized by constriction of both pulmonary arteries and pulmonary veins. The capillary wedge pressure did not reflect the pulmonary microvascular pressure, since it varied in the opposite direction to the effective capillary pressure.

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PubMed1984

Fundic vagotomy by waveguide CO2 laser: experimental study of a new technique in dogs.

Anterior lesser curve seromyotomy with posterior truncal vagotomy is an alternative operation to the highly selective vagotomy. After preoperative gastric function testing, four dogs underwent an anterior lesser curve seromyotomy with posterior truncal vagotomy. However, a new prototype hand-held laser was used to perform the seromyotomy. This laser delivers 20 W and is small, light, and highly maneuverable. Results of the operation indicate that this laser was easy to use and yielded a very effective seromyotomy without complications. Peroperatively, the laser performed simultaneous section and hemostasis. Postoperatively, no significant acid production could be stimulated with either histamine, pentagastrin, or insulin. This operation yields good control of acid production and is faster and easier than the highly selective vagotomy. The hand-held waveguide CO2 laser may further facilitate the ease of this procedure.

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PubMedDate not supplied

[Gallbladder volvulus].

We report two new cases of gallbladder volvulus. This rare condition principally affects elderly patients but is due to a congenital malformation related to the presence of a long mesocyst. Various factors such as kyphoscoliosis, multiparity and peristalsis of neighbouring organs favorise the occurrence of volvulus, the role of lithiasis is debatable. The diagnosis may be suggested on ultrasound but is most often confirmed at laparotomy. Diagnosis should be made rapidly in order to avoid progression towards a potentially fatal secondary peritonitis. Certain clinical elements such as the presence of a "floating mass" on palpation may suggest the diagnosis.

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