Extended (29 days) use of intravascular gas exchanger.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
M Lachat
Publications and source records attributed to M Lachat.
Temporary lung support using an intravascular gas exchanger.
Severe respiratory failure may be difficult to overcome by conventional mechanical ventilation. As an alternative to the very demanding lung support using various modalities of extracorporeal circulation (ECMO, ECLA, etc.) we evaluated an intravascular gas exchanger (IVOX) in a "reversible" bovine model. Several degrees of hypoventilation were studied with and without intravascular gas exchange in 5 endotracheal intubated, anaesthetized, and volume-controlled ventilated animals (body weight 73 +/- 4 kg). After systematical heparinization (300 IU/kg body weight) the animals were instrumented with EKG electrodes, thermodilution pulmonary artery catheter with continuous measurement of O2-saturation, central venous and femoral arterial catheter, etc. The intravascular gas exchanger made from siliconized microporous polypropylene hollow fibres was placed in the caval veins under radiofluoroscopic control. The following scenarios were studied without and with intravascular gas exchange (gas inlet 100% O2): Normoventilation (with 14-20 strokes/min) at F10(2) 0.50 and at F10(2) 0.21; Hypoventilation (ventilator frequency reduced to 50% and tidal volume reduced to 50% of normoventilation) at F10(2) 0.50 and at F10(2) 0.21. Hemodynamics, mixed venous O2-saturation, arterial and venous blood gases, and gas-exchanger exhaust were analyzed after stabilization over 15 minutes (mean +/- standard deviation). Blood gas analyses showed significant improvement with intravascular gas exchange during hypoventilation at F10(2) 0.21: pH moved from 7.10 +/- 0.17 to 7.19 +/- 0.15*, PaCO2 moved from 9.9 +/- 4.2 kPa to 8.7 +/- 2.8*, PaO2 moved from 6.5 +/- 1.2 kPa to 7.3 +/- 0.8* and mixed venous O2-saturation moved from 33.9 +/- 16.0% to 48.1 +/- 4.6* (* = p less than 0.05 for without versus with intravascular gas exchange).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Resorbable pericardial replacement--an experimental study].
The resorbable pericardial substitute: In modern heart surgery every patient undergoing cardiac surgery will eventually require a second operation including resternotomy. To reduce the risk of damage to the heart it has been recommended to close the pericardial sac primarily. Unfortunately there is no ideal pericardial substitute yet available. This experimental study summarizes our experience with the use of Gore-Tex Surgical Membrane and Vicryl-Collagen mesh as pericardial substitutes which have been implanted orthotopically in 12 rats. After a mean follow-up of 86 days we evaluated macroscopically the pericardial adhesions, the closure of the pericardial defect and histologically the inflammatory reaction. At explanation we found that both pericardial substitutes produce little adhesion. But in rats with Vicryl-Collagen mesh as a pericardial substitute there were only a very few inflammatory cells and total closure of the pericardial defect was in 4 out of 6 rats present. These findings suggest that Vicryl-Collagen mesh seems to be a superior pericardial substitute and also allows formation of a neopericardium.
Animals↗
[Effect of hemodynamic conditions and prosthesis structure on endothelialization of clinical and experimental small lumen vascular prostheses].
Seeding of small-diameter vascular prostheses (ID less than or equal to 6 mm) with autologous microvascular cells (AMVC) results in a complete endothelial cell layer on the luminal surface. The purpose of this study was to examine the influence of the blood flow velocity (due to 4 or 6 mm ID) and the structure of inner graft surface (crimped, uncrimped) on the endothelialization. AMVC were harvested from omental adipose tissue (mean: 0.56 X 10(6) cells/g tissue) from 10 mongrel dogs (mean: 27.9 kg). During preclotting, the 4 mm uncrimped and the 6 mm crimped double velour Dacron prostheses (Meadox Medicals, Inc.) were seeded with 1.0 X 10(6) cells/cm2 graft surface. Grafts were implanted into the carotid arteries (N = 5 in each group). The animals received antiplatelet therapy. After five weeks, all seeded prostheses were patent. The thrombus free surface (TFS) of seeded prostheses was 99.9% (4 mm) and 90.5% (6 mm). Scanning electron microscopy revealed an athrombogenic layer of endothelial cells on a smooth surface. -It is concluded that in canine experiments endothelialization of 4 and 6 mm grafts after seeding with AMVC is not affected by blood flow velocity or graft structure.
Animals↗
Performance characteristics of centrifugal pumps with heparin surface coating.
Heparin surface coating is one approach to improve the biocompatibility of existing blood pumps used for mechanical circulatory support. Experimental evaluation of centrifugal pumps with heparin surface coating was performed during open chest left heart bypass (3.7 L/min over 6 hours) in two series of bovine experiments. Eight calves (74 +/- 4 kg) were perfused either by heparin surface coated equipment without systemic heparinization or uncoated equipment with systemic heparinization (300 I. U,/kg bodyweight; ACT greater than 400 s). A standard battery of analyses was performed before and at regular intervals after onset of perfusion. At the end of perfusion all pump-heads were gently rinsed. There were no macroscopic clots for both groups whereas macroscopic clots were observed in uncoated tubings introduced for control in the group perfused without systemic heparinization. The hemodynamics were significantly better in the group perfused without systemic heparinization and maintained functional coagulation system. Clinical application of heparin surface coated equipment during resection of thoraco-abdominal aortic aneurysms is showing promising results in 12 patients.
Animals↗
[Endothelialization of 6 mm vascular prostheses with microvascular endothelial cells from fatty tissue of the omentum].
The seeding of 6 mm Dacron prostheses with microvascular endothelial cells from omental adipose tissue leads to endothelialized prostheses, 5 weeks later with a complete coverage of functional and thrombus free endothelium. The method is ready for clinical trials.
Adipose Tissue↗
[Bile duct reconstruction in liver transplantation].
Complications of the biliary anatomosis are common after liver transplantation. Even with improved techniques the frequency of biliary complications is approximately ten percent. Main reason for this high morbidity rate is the unfavourable blood supply to the biliary tract. A variant of reconstructions has been described and recommended. The end-to-end-choledochocholedochostomy over a T tube turned out to be the preferred technique in most centers. In cases of different diameter of donor and recipient biliary tract, the side-to-side-choledochocholedochostomy provides a relayable alternative method. When the length of the bile duct doesn't allow direct anastomosis, the gallbladder-conduit may help to overcome this problem. The choledochojejunostomy with Roux-en-Y loop has become a frequently used biliary anastomosis, especially when the recipients bile duct is absent or otherwise destroyed. - Our own experience with fourteen liver transplantations shows biliary tract complications in three cases: a leakage and a stenosis of the anastomosis after choledochocholedochostomy were successfully transformed to a hepaticojejunostomy. In the third case, intrahepatic biliary stenosis were treated by percutaneous transhepatic dilatation.
Adult↗
Late neutrophil infiltration of canine endothelial cell seeded Dacron grafts.
Neutrophil infiltration is known to affect the endothelial monolayer of seeded vascular grafts. The aim of this study was to develop an in vitro system allowing the monitoring of neutrophil (PMN) adherence after graft implantation. Dacron prostheses were seeded with autologous canine microvascular cells from omental adipose tissue and implanted for 35 days. In vitro, mature monolayers of canine homologous venous endothelial cells (CHVENC) were exposed to heparinized whole blood samples taken at days one and four postoperatively, followed by weekly tests. PMNs adherent to the CHVENC were counted per culture area. Results showed the feasibility of PMN monitoring, and demonstrated a late PMN adhesion, reaching its maximum about 20 days after implantation and decreasing to normal values after five weeks. It is concluded that in vitro tests can be used for noninvasive studies of host plasma factors and leukocyte activation.
Animals↗
[Primary lymphedema and pregnancy].
From a retrospective analysis of 15 female patients, it appears that primary lymphedema, reversible at first, tends to become irreversible during successive pregnancies. A remission takes place following the first and second pregnancy, and during a third pregnancy, an irreversible stage is reached.
Adolescent↗