PubMed Health⌕ Search

Biomedical subjects

B J Bridgewater

Publications and source records attributed to B J Bridgewater.

8 recordsLinked to original sources
PubMed1996

Comparison of saccharides as osmotic impermeants during hypothermic lung graft preservation.

We have previously shown that the trisaccharide raffinose is largely responsible for the superior lung graft performance seen after storage in University of Wisconsin solution. To investigate the use of osmotic agents in perfusates for hypothermic lung graft storage, we compared saccharides of various molecular weights in an isolated rat lung model. Grafts were flushed with 1 of 6 preservation solutions (n=5 each group) containing either a monosaccharide (glucose [G] or fructose [F]), disaccharide (trehalose [T] or sucrose [S]), or trisaccharide (raffinose [R] or melezitose [M]. Grafts were stored for 6 hours at 4 degrees C, reperfused by a veno-venous circuit from an anesthetized support animal for 60 min, and ventilated with room air. The best graft function was seen when trisaccharides were used (PO2; R 126 +/- 3 mm Hg, M 129 +/- 3 mm Hg, blood flows: R 10.2 +/- 0.42 ml/min, M 10.3 +/- 0.22 ml/min). Disaccharides produced similar oxygenation (T 133 +/- 3 mm Hg, S 129 +/- 3 mm Hg) and flows (T 10.3 +/- 0.29 ml/min, S 9.7 +/- 0.4 ml/min) at 60 min, but initial flows were reduced. Monosaccharides produced the least satisfactory graft function, with impaired oxygenation (F 110 +/- 14 mm Hg, P<0.05; G 69 +/- 10 mm Hg, P<0.01) and blood flows (G 6.5 +/- 0.6 ml/min, F 9.1 +/- 0.6 ml/min, P<0.01 each). Only glucose-stored lungs demonstrated a significant decrease in compliance (P<0.01) and weight gain (P<0.01). The worst results were seen with glucose, which is the osmotic agent most commonly used for clinical lung storage. A solution containing a trisaccharide or disaccharide may be more appropriate for this purpose.

Animals↗
PubMed1996

Controlled pressure reperfusion of rat pulmonary grafts yields improved function after twenty-four-hours' cold storage in University of Wisconsin solution.

BACKGROUND: Pulmonary graft recipients commonly have a degree of pulmonary hypertension. Immediate reperfusion of stored pulmonary grafts at supraphysiologic or even physiologic pressures may be detrimental to subsequent function. We wished to test the hypothesis that initial reperfusion of pulmonary grafts at low pressures may be beneficial. METHODS: We used an isolated, ventilated rat lung model, perfused by an extracorporeal veno-venous circuit from a support animal. Three groups of donor lungs (n = 5 each) were flushed with cold University of Wisconsin solution. Group I was reperfused immediately at physiologic pressure to provide control values. Group II grafts were stored at 4 degrees C for 24 hours and reperfused at physiologic pressure. Group III grafts were also stored at 4 degrees C for 24 hours but reperfused according to a protocol of reduced pressure initially, with increments every 15 minutes up to physiologic levels by 60 minutes. Grafts and support animals were ventilated with room air. Graft function was assessed over a 2-hour period with regard to oxygenation, vascular resistance, peak airway pressure, and the wet/dry weight ratio. RESULTS: Grafts in group II functioned poorly at 2 hours compared with control values: group II: oxygen tension 68 +/- 4 mm Hg; pulmonary vascular resistance 2488 +/- 675 x 10(3) dyne.sec/cm5; peak airway pressure 32 +/- 1 mm Hg wet/dry wright ratio 9.1 +/- Group I: oxygen tension 136 +/- 2 mm Hg; pulmonary vascular resistance 120 +/- 3 x 10(3) dyne.sec/cm5; peak airway pressure 13 +/- 1 mm Hg and wet/dry weight ratio 3.6 +/- 0.3; p < 0.001 all parameters except pulmonary vascular resistance: p < 0.05. In contrast, grafts undergoing controlled pressure reperfusion (group III) achieved function comparable with baseline values at 2 hours: oxygen tension 137 +/- 3 mm Hg; pulmonary vascular resistance 132 +/- 7 x 10(3) dyne. sec/cm5; peak airway pressure 13 +/- 1 mm Hg; wet/dry weight ratio 4.1 +/- 0.3 (p = Not significant). CONCLUSIONS: The pressure at which pulmonary grafts are initially reperfused appears to be critical to their subsequent integrity. A protocol of controlled reperfusion may reduce reperfusion injury and improve graft function in clinical practice.

Adenosine↗
PubMed1994

Lung graft preservation. Comparison of phosphate-buffered sucrose, modified EuroCollins, and University of Wisconsin solutions.

Phosphate-buffered sucrose (PBS) has been shown to be highly effective for renal graft storage. It may, therefore, be useful for lung graft storage. Recent studies have suggested a possible role for University of Wisconsin (UW) solution in lung preservation. The object of this study was to evaluate these two solutions in comparison with EuroCollins (EC) solution for lung graft preservation in an isolated rat lung model. Lungs were stored for 6 hr at 4 degrees C after a single pulmonary artery flush with either PBS with prostacyclin (n = 10), EC with prostacyclin (n = 5), or UW (n = 5) solution. Reperfusion of the isolated lung was carried out for 1 hr using a venovenous extracorporeal circulation from a ventilated support rat. The support animals and isolated lungs were ventilated with room air. Control values were obtained from lungs reperfused immediately after harvesting (n = 5). At 1 hr, PBS provided a similar level of protection to EC: pO2, 45 +/- 10 mmHg and 54 +/- 6 mmHg; graft blood flow, 4.1 +/- 1.2 ml/min and 3.5 +/- 0.42 ml/min; peak airway pressure, 32 +/- 2.5 mmHg and 36 +/- 3.6 mmHg; weight gain, 4.1 +/- 0.6 g and 4.2 +/- 0.6 g, respectively (P = NS). However, the UW group provided superior function, which was similar to the control group: pO2, 128 +/- 2.7 mmHg and 126 +/- 5 mmHg; graft blood flow, 9.9 +/- 0.4 ml/min and 10.2 +/- 0.8 ml/min; peak airway pressure, 17.6 +/- 0.4 mmHg and 16.5 +/- 0.6 mmHg; weight gain, 0.12 +/- 0.1 g and 0.19 +/- 0.13 g, respectively (P = NS). UW was superior in all parameters to PBS and EC (P < 0.001). This suggests that the renal solutions PBS and EC are inappropriate for lung graft preservation, and that the requirements of the lung during hypothermic storage differ from those of the kidney.

Adenosine↗
PubMed1993

Quantifying the effect of intravascular perfluorocarbon on xenon elimination from canine muscle.

Intravenous infusions of perfluorocarbon (PFC) may improve decompression sickness outcome in animals by accelerating inert gas elimination from tissue, but any such effect has not been quantified experimentally. In this study we used an animal model of tissue Xe kinetics to test this hypothesis and to quantify the effect of PFC. Eight dogs were ventilated with dilute 133Xe in air for 4 h of Xe uptake. Four dogs were then given an infusion (20 ml/kg iv) of a 40% (vol/vol) perfluorodecalin-glycerol emulsion, and four control dogs were given only isotonic glycerol. All were then switched to open-circuit air breathing for 4 h of Xe elimination. During this time Xe radioactivity-time curves were recorded from two intact hind leg muscles, and the Xe mean residence times during elimination were estimated using an analysis by moments and compared by group. Tissue blood flows were measured using microspheres once during Xe uptake and twice during Xe elimination, and cardiac outputs were measured by thermodilution at 30-min intervals. In the PFC group the measured circulating PFC fraction increased the calculated Xe solubility by an average factor of 1.77 and so was expected to increase the Xe elimination rate by 77%. The observed Xe mean residence times on elimination for the PFC group averaged 33.5 min [95% confidence interval (CI) 19.5-47.6] compared with the glycerol control average of 70.1 min (95% CI 56.1-84.2), representing an increase in the rate of Xe elimination by a factor of 2.09 or 109%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Aorto-cutaneous fistula: a rare complication of aortic surgery.

Two cases of false aneurysm of the ascending aorta which presented with discharge of arterial blood from a sternal wound are discussed. The first presented 8 years after aortic valve surgery and was diagnosed by contrast enhanced computerised tomography of the thorax. The second presented 6 months following repair of an aortic dissection and the diagnosis was confirmed by thoracic magnetic resonance imaging. The diagnosis and surgical management of these cases are reviewed.

Aged↗
PubMedDate not supplied

University of Wisconsin solution for lung graft preservation: which components are important?

Rat lung grafts were perfused with either Euro-Collins solution, University of Wisconsin solution, or one of six modified University of Wisconsin solutions that had been sequentially depleted of specific components (n = 5 each group). After storage at 4 degrees C for 6 hours, the isolated, ventilated pulmonary graft was reperfused for 1 hour with recirculating venous blood from a support animal. In a further group, lungs were reperfused immediately after explanation to provide control values. Grafts flushed with University of Wisconsin solution functioned at control levels with regard to oxygen tension: University of Wisconsin solution 128 +/- 2.7 mm Hg, control 126 +/- 5 mm Hg; graft blood flow: University of Wisconsin solution 9.9 +/- 0.4 ml/min, control 10.2 +/- 0.8 ml/min; peak airway pressure: University of Wisconsin solution 17 +/- 0.5 mm Hg, control 16.5 +/- 0.6 mm Hg; and weight gain: University of Wisconsin solution 0.12 +2- 0.1 gm, control 0.19 +/- 0.13 gm. In contrast, lungs treated with Euro-Collins solution functioned less well: oxygen tension 54 +/- 6 mm Hg, graft blood flow 3.5 +/- 0.42 ml/min, peak airway pressure 35 +/- 4 mm Hg, and weight gain 4.15 +/- 0.5 gm (p < 0.0001 all parameters). Sequential removal of hydroxyethyl starch, magnesium, allopurinol, adenosine, glutathione, and lactobionate from University of Wisconsin solution did not impair the efficacy of the solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗