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B D Lowery

Publications and source records attributed to B D Lowery.

At least 19 recordsLinked to original sources
PubMed1987

Complement depletion in a porcine model of septic acute respiratory disease.

In a porcine model of severe septic acute respiratory failure produced by continuous infusion of live Pseudomonas aeruginosa, the role of the complement system was studied by pretreating animals with cobra venom factor (CVF) to deplete C3. Three groups of spontaneously breathing animals were monitored with Swan-Ganz and arterial thermodilution catheters. Group I was pretreated with 80 U/kg of CVF iv 16-18 hours before testing. Group II received Ps. aeruginosa iv (2 X 10(8)/20 kg/minute). Group III was pretreated with CVF and later given the Pseudomonas infusion. The CH50 as a measure of complement activity was less than 7% of normal level in Groups I and III. No changes in respiratory variables occurred in Group I. In Group II, the mean pulmonary artery pressure doubled, intrapulmonary shunt fraction (Qs/Qt) increased, PaO2 decreased, and extravascular lung water doubled in 4 hours. In Group III, the pulmonary hypertension, hypoxemia, increase in Qs/Qt, and increase in EVLW were all significantly less than in Group II. Neutropenia occurred with the Pseudomonas infusion in Groups II and III.

Animals↗
PubMed1983

Comparison of live bacteria infusions in a porcine model of acute respiratory failure.

Acute respiratory failure (ARF) related to sepsis continues to have a high mortality and uncertain pathogenesis. With a reproducible live Pseudomonas aeruginosa infusion pig model, the gas exchange, hemodynamics, and pulmonary clearance of this organism were compared with live Staphylococcus aureus and Escherichia coli. Lightly anesthetized, male, mixed-breed pigs, 15-30 kg, were intubated, allowed to breathe spontaneously, and had femoral artery, central venous, and Swan-Ganz catheterization through cutdowns. After baseline data were collected, approximately 1 X 10(9) organisms/20 kg/min were infused into a central vein for 4 hr with frequent monitoring of the variables. Immediate autopsies were done for related quantitative tissue culture studies. S. aureus pigs maintained a high rate of lung bacterial clearance with pulmonary hypertension, a nonsignificant decrease in PaO2, and relatively normal lungs at autopsy. Ps. aeruginosa and E. coli animals developed systemic hypotension, pulmonary hypertension, increased pulmonary vascular resistance, hypoxemia, and decreased pulmonary clearance. Their lungs had gross congestion and edema. These studies confirm the suitability of E. coli and Ps. aeruginosa infusion into pigs as a model of sepsis-induced ARF in man. The findings also indicate that neither pulmonary hypertension nor bacterial clearance by the lungs is sufficient to cause ARF.

Acute Disease↗
PubMed1983

Prostacyclin in experimental septic acute respiratory failure.

Manipulation of prostaglandins (PG) in animal models of sepsis and acute respiratory failure (ARF) is promising. Prostacyclin (PGI2), a short-acting vasodilator, was evaluated in a porcine model of ARF produced by continuous infusion of live Pseudomonas aeruginosa (Ps.). Cardiopulmonary parameters were monitored in three groups of spontaneously breathing animals that received 0.1 micrograms PGI2/kg/min begun 20 min after baseline (Group I); 2 X 10(8) Ps./20 kg/min (Group II); identical Ps. infusion and then PGI2 begun at 20 min (Group III). The decrease in mean arterial blood pressure and cardiac index with Ps. infusion was improved by PGI2 treatment. In Groups II and III, mean pulmonary artery pressure (PAP) doubled (P less than 0.005) and pulmonary vascular resistance (PVR) tripled (P less than 0.01) by 15 min. Both PAP and PVR were decreased significantly with PGI2 treatment. In both Ps. groups, significant hypoxemia occurred. PGI2 improves cardiac output and acts as a pulmonary vasodilator, but does not improve oxygenation in this porcine model of severe ARF.

Acute Disease↗
PubMed1983

Indomethacin improvement of septic acute respiratory failure in a porcine model.

The effects of indomethacin, a prostaglandin synthesis blocker, were tested in a porcine model of septic acute respiratory failure (ARF) produced by continuous infusion of live Ps. aeruginosa. Control groups received either indomethacin boluses (2 mg/kg) intravenously at 20 and 210 minutes or Ps. aeruginosa infusion (2 X 10(8) CFU/20 kg/min). The treatment group received both continuous Ps. aeruginosa infusion and indomethacin. Indomethacin alone transiently but significantly decreased cardiac indices, heart rate, and PaCO2. With Ps. aeruginosa infusion, significant pulmonary hypertension, hypoxemia, increased intrapulmonary shunt fraction, and systemic hypotension occurred. In this porcine model of septic ARF, indomethacin doubled the survival period and improved cardiopulmonary parameters.

Acute Disease↗
PubMed1981

Bacteremia: host-specific lung clearance and pulmonary failure.

Pulmonary effects, lung clearance, and tissue retention of blood-borne Pseudomonas aeruginosa were compared in dogs (n = 5) and pigs (n = 5) during continuous 6-hour intravenous infusion of 1.2(10(9)) bacteria/min/20 kg. Control pigs received an equal volume of sterile saline. In contrast to controls, experimental pigs developed pulmonary artery (PA) hypertension (mean, 30 +/- SE 3; baseline, 17 mm Hg) and pulmonary failure manifested by hypoxemia (mean PaO2, 49 +/- 4; baseline, 78 +/- 2 mm Hg; p less than 0.001), increased intrapulmonary shunting (40 to 50%), noncardiogenic pulmonary edema, and congestive atelectasis, a pattern of pulmonary failure very similar to sepsis-induced ARDS in humans. In dogs, PA pressures wee unchanged from baseline, no edema was detected, and comparable hyperventilation was associated with an increase in PaO2 from 77 +/- 4 (baseline) to 87 +/- 2 mm Hg (p less than 0.001). Tissue retention of viable blood-borne organisms in pigs was greatest in the lungs. In dogs, lung retention was minimal and greatest tissue retention occurred in the liver and spleen. We conclude that both lung clearance of blood-borne organisms and bacteremia-induced pulmonary failure are quite host dependent.

Animals↗
PubMed1981

Pulmonary clearance of blood-borne bacteria.

Clearance of blood-borne bacteria has been attributed primarily to a fixed macrophages in the liver and spleen. Although many important nonrespiratory functions of the lung have been reported, a major role for this organ in the clearance of circulating bacteria has not been described. To investigate mechanisms of sepsis induced lung dysfunction and pneumonia, we measured lung clearance, tissue accumulation and morphologic effect of blood-borne. Pseudomonas aeruginosa in pigs. Single pass pulmonary clearance of 60 to 80 per cent occurred over a wide range of infusion concentrations. Tissue concentrations of viable, hematogenously delivered bacteria were greatest in the lungs and exceeded inflowing blood concentrations in the lungs, liver and spleen but were less than inflowing blood concentrations in the heart, kidney and skeletal muscle. Electron microscopy showed phagocytosis of bacteria predominantly by mononuclear cells located within small pulmonary vessels. Viable test organisms were recovered from the upper airways of pigs receiving high dose bacterial infusions but not from pigs in the control group. In this experimental model, an important nonrespiratory function of the lungs is clearance of blood-borne bacteria. If lungs in humans have a similar capacity, retention of circulating organisms may be one mechanism of sepsis induced pulmonary failure.

Animals↗
PubMed1976

Septic nonsuppurative thrombophlebitis.

Nonsuppurative peripheral thrombophlebitis is a frequently recognized source of sepsis. Eleven patients cared for on general medical and surgical services had Gram-negative bacillary sepsis on this basis. Ten had isolation of organisms of the Klebsiella-Enterobacter group from the involved peripheral vein. All failed to respond to organism-sensitive antibiotics until the involved vein was excised. After local vein excision, all patients were afebrile within 48 hours and recovered. In seven of the 11 patients, the septic phlebitis source was associated with a standard intravenous needle, and none had cutdown procedures. It is strongly emphasized that this condition is a source of life-threatening sepsis that can be treated by vein excision at the bedside. The treatment in our patients resulted in no morbidity. A high index of suspicion is necessary to diagnose this occult source of sepsis because of the minimal local physical signs.

Adult↗
PubMed1975

Pulmonary hyperinflation. A form of barotrauma during mechanical ventilation.

Barotrauma has been used to describe several specific complications related to mechanical ventilation. These include tension lung cyst, pneumothorax, pneumomediastinum, pneumoperitoneum, and subcutaneous emphysema. Pulmonary hyperinflation, another such complication, occurred in 6 patients, being fatal in 3. Two pathophysiologic mechanisms are discussed. The simpler, and well-recognized, ball-valve airway obstruction allows inspiration of air delivered by the mechanical ventilator but prevents expiration. A more complex circumstance exists when pulmonary contusion or infiltration produces differential lung compliances. This allows extreme hyperinflation of areas of normal lung during attempts to ventilate abnormal lung of low compliance. This mechanism is particularly evident when positive end-expiratory pressure (PEEP) is used in an attempt to open collapsed ventilatory units. Functional complications of lung hyperinflation include decreased alveolar ventilation and compression effects on adjacent structures. Interference with and shifts of regional lung perfusion may worsen gas exchange. Proper treatment includes airway clearance by bronchoscopy, the judicious use of bronchodilators, the discontinuance of PEEP, and adjustments of mechanical ventilators to prevent high airway pressures.

Adult↗
PubMed1971

Hemorrhagic shock.

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Acid-Base Equilibrium↗