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Biomedical subjects

D Loisance

Publications and source records attributed to D Loisance.

At least 199 records · Page 11Linked to original sources
PubMed1978

[Resections of the left ventricle in the surgical treatment of parietal sequelae of myocardial infarct].

Resection of left ventricular tissue seems to be playing an increasing part in the treatment of the sequelae of myocardial infarction. In a total of 700 patients who underwent surgery for some aspect of coronary atherosclerosis, 40 underwent resection of left ventricular tissue. In the majority of cases, diagnosis rested on left ventricular cine-angiography and in 3 cases this had to be carried out as an urgent procedure with circulatory assistance using diastolic counter-pressure (DCP) from an intra-aortic balloon. A selective contrast technique for the two coronary arteries was used whenever possible. The surgical anatomy of the lesions indicates a difference between a localised dyskinesia and diffuse dyskinesia, the latter having a severe effect on left ventricular function. In a group of localised dyskinesias, the territory supplied by the anterior descending artery was by far the most frequently affected. Resection of left ventricular tissue was associated with a myocardial bypass revascularisation procedure in 9 cases, valve repair in 7 cases, and closure of a septal perforation in 3 cases. The total inpatient mortality rate is still quite high (23.1%) because of the severity and widespread nature of the coronary disease. However, the mid-and long-term results are good, the criteria being functional improvement and the actuarial 4-year survival rate.

Adult↗
PubMed1978

Pulmonary gas exchange during venoarterial bypass with a membrane lung for acute respiratory failure.

In patients with fulminating pulmonary edema not responsive to conventional therapy, venoarterial membrane lung bypass can provide assistance if decreased systemic blood pressure prevents use of high-level positive end-expiratory pressure ventilation. In 10 patients with acute respiratory failure, partial venoarterial bypass provided a rapid and marked improvement of systemic oxygenation. Measurement of pulmonary blood flow (PBF) and intrapulmonary shunting (QS/QP) during bypass via prolonged left heart catheterization showed that left ventricular PaO2 was increased through a rapid and profound reduction of QS/QP. During the first days of bypass, derecruitment of pulmonary vessels is probably the mechanism of improved pulmonary oxygenation. When low pulmonary arterial pressures (PAP) are sustained, resorption of pulmonary edema is favored. Despite the beneficial effects of bypass, death occurred in every case due to diffuse interstitial fibrosis and/or parenchymal damage. The absence of healing, due to prolonged circulatory exclusion, may be detrimental despite immediate improvement. Because of this possibility, venovenous or mixed perfusion should be more extensively explored.

Acute Disease↗
PubMed1977

[Mitral replacement using a ball-valve prosthesis under hypothermic protection of the myocardium. 230 cases].

A series of 230 mitral valve replacements using exclusively the Starr-Edwards ball valve prosthesis is presented. These 230 patients underwent surgery over a 4 year period, a uniform operative technique being used. Its essential feature was the use of a standardised technique for protection of the myocardium based upon continous clamping of the aorta and deep hypothermia at around 15 degrees. The technique of myocardial hypothermia, already reported, is briefly reviewed. The results are analysed, in the short and long term. Overall hospital mortality was 6.9 per cent, including multiple valve replacements and combined coronary surgery. The total number of thrombo-embolic complications was 8, including 1 early thrombosis out of 230 patients - i.e. 0.4 per cent and 7 late thrombo-embolic episodes out of 180 patients followed up for 1 month to 4 years - i.e. 3.8 per cent. Secondary and late mortality was 11 cases out of 180 patients. The survival rate at 4 years was 78 per cent by actuarial calculation, including operative mortality. These results justify the continued use of ball prosthesis, the long term thrombo-embolic risks of which are equal to or less than those of disc prosthesis, and the resistance of which to wear and tear is shown by the long postoperative survivals.

Adult↗
PubMed1977

[In vitro and in vivo study of a hemoglobin solution used as a blood substitute].

In vitro studies of a stroma free haemoglobin solution of human origin (Wx B 8326, Warner-Lambert) in comparison with fresh and stored low DPG whole human blood, was undertaken with regard to the fixation. of oxygen. Such an hemoglobin solution was shown to exhibit a high affinity for oxygen and a low Bohr effect (assessed from the delta log Po2/delta pH ratio). The specific effect of Co2 (assessed from the delta log Po2/delta log. Pco2 ratio) appeared to be increased as compared to fresh whole blood. This hemoglobin solution was tested as a blood substitute in two in vivo experimental situations: exsanguino transfusion on rabbits (n = 6) and closed-chest extracorporeal circulation on dogs (n = 6). In order to evaluate the part taken by the tested Hb solution in arterial O2 carrying capacity and in O2 delivery, two ratios were calculated: arterial plasmatic O2 content/arterial circulating blood O2 content and arterio-venous plasmatic O2 difference/arterio-venous circulating blood O2 difference. These two ratios amounted 28,2 +/- 2,5% (rabbits) and 47,0 +/- 6% (dogs) for the arterial O2 carrying capacity and 13,8 +/- 3,0% (rabbits) and 25,8 +/- 5,0% (dogs) for the tissular O2 delivery. Among the properties of the tested stroma free hemoglobin solution its low contribution to the tissular O2 delivery, its high affinity for oxygen, its low Bohr effect and its short half-life as compared to whole blood are not favouring its use in clinical practice.

Acid-Base Equilibrium↗
PubMed1977

[Early neurological complications after cardiac surgery under ECC].

A non-trifling frequency (3,3 p. 100) of neurologic complications is observed after surgery under E.C.C. The part of some factors has been analysed and discussed, especially those played by the type of the system used, quality of the E.C.C., and the patients' conditions. Many problems are still unresolved. The actual gravity of observed troubles must bring a better harshness in preventive treatment, and to a more adjusted treatment when these troubles are noted.

Adolescent↗
PubMed1977

[Proteins and blood volume after cardiac surgery under ECC and hemodilution].

The variations in protein, bodyweight and circulating blood volume during operation are studied in 18 patients operated under ECC. The frequency of hypovolemia with hypoproteinemia and over hydration of the interstitial medium is confirmed. The prolongation of ECC beyond 120 minutes is accompanied by a considerable reduction in the plasma sector. The frequency of hypovolemia must render the use of diuretics prudent. The existence of hypoproteinemia and interstitial overload suggests the value of albumin perfusions.

Blood↗
PubMed1977

[Kidney failure after ectracorporeal circulation in cardiac surgery].

The renal function of 113 patients undergoing cardiac surgery under ECC was studied. In 32 p. 100 of the cases renal involvement was noted which was moderate in 18 p. 100 of the cases, severe in 10 p. 100 of the cases and anuric in 4 p. 100 of the cases. Valvular surgery was complicated once in every three cases by renal involvement, the repair of congenital malformations once out of every two cases, and coronary surgery in 17 p. 100 of the cases. The fall in renal perfusion represents the essential factor in this renal involvement, which should be avoided by the maintenace during ECC of a high output level and a satisfactory perfusion pressure and by the recovery of correct hemodynamics after the intervention.

Acute Kidney Injury↗
PubMed1976

[Amiodarone hydrochloride and anesthesia in heart surgery. Use of an injectable form in the correction of peroperative rhythm disorders].

The amiodarone is studied in the context of cardiac surgery to evaluate its anti-arrythmic properties in its injectable form and possible interference with the anaesthetic drugs. Two groups of patients were established: - the first group of 10 patients received the amiodarone per-os in the immediate pre-operative period, - the second group of 19 patients received injectable amiodarone either by direct intraveinous injection at a dose of 5 mg/kg or in I.V. drip for rhytmic irregulatities during surgery. The anti-arrythmic property of the product is confirmed. No incompatibility with the anaesthetics employed (neuroleptanalgesia) was observed. Howerer, a potentialization of the sympatholytic alpha-effects by the anaesthesia is observed. The fall in arterial pressure, when it is measureable, is of the order of a third of the initial value, with a return to the previous level within about ten minutes.

Adolescent↗
PubMed1976

Biochemical studies on dacron arterial prostheses.

Dacron arterial prostheses, treated or not with biopolymers (gelatin, glycosaminoglycans) were implanted in the abdominal aorta of dogs and the connective tissue synthetised inside and outside the prosthesis was studied. After 3 and 9 months of implantation the prosthesis, a joining portion and a piece of aorta were excised and put in organ culture with 14C-lysine for 3 days. Representative macromolecular extracts were then obtained by a "chemical dissection" procedure. The radioactivity and the chemical composition of these extracts was studied. The DNA content of the prosthesis was higher than that of the adjacent aorta showing a dense cellular repopulation of the prosthesis. This was confirmed by histology also which revealed the presence of a newly formed limiting elastic membrane and the presence of numerous elastic fibrils. Collagen, elastin and glycosaminoglycans could be detected in the macromolecular extracts showing that the cells which repopulated the prosthesis expressed a complete biosynthetic capacity as far as matrix macromolecules are concerned. The distribution of proteins in the extracts was as follows: 4% of total proteins were extracted in a 1M CaCl2-buffer 80% of total proteins in the collagenase extracts, 10% in the 6M urea extract. Only 0,2% of proteins were in the final elastase extract, 10 times less than in the joining aorta fragment. The proportion of the other proteins was similar in aorta and in the prosthesis as well as the chemical composition (hexosamine and hydroxyproline content) of the extracts. The proportion of collagenase-extractable proteins decreased with the time of implantation (from 3 to 9 months) and the proportion of urea-extractable proteins increased. This type of modification is similar to that found in aging aorta wall. 14C-lysine was actively incorporated in all macromolecular fractions studied. The incorporation pattern of the prothesis tissue was similar to that found for the joining host aorta, showing a similar regulatory tendency for matrix macromolecules. It appears therefore that a valid hemocompatible vascular type of connective tissue can be synthesised on the dacron arterial prosthesis and nature of this connective tissue can be influenced by previous biopolymer treatment of the synthetic prosthesis. The described procedure (incorporation of labelled precursors in organ culture) appears to be a valid method for the exploration of the regulatory processes underlying the synthetic capacity for matrix macromolecules of the newly formed tissue in the synthetic prosthesis.

Animals↗
PubMed1976

[Membrane oxygenators in cardiac surgery: progress].

This study tries to define if the membrane oxygenators are available during cardiac surgery under E.C.C., and if their performance are superior to those of conventional oxygenators. Two series of research are done. In the first one, we compare performance of two membrane oxygenators: the Rhône-Poulenc heart-lung machine (10 cases) and the Travenol TMO Teflo machine (100 cases). The general impression is good: the two proposed systems seem to be perfectly well adapted to surgical utilization conditions, avoiding excessive ventilations and eventually allowing to keep on E.C.C. in postoperative. In the second part of this work, two series of patients are studied, one oeprated under membrane oxygenator (Teflo), the second under bubble oxygenator (Bentley Q 100). Comparative study shows small differences between the two groups. Only the post-operative enzymatic profile is clearly for the membrane oxygenator which also insure a waking and a postoperative recovery of highest quality. These first observations justify to keep on using of membrane oxygenators in cardiac surgery.

Cardiac Surgical Procedures↗