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Biomedical subjects

C Knothe

Publications and source records attributed to C Knothe.

42 records · Page 3Linked to original sources

The role of enoximone in cardiac surgery.

After cardiopulmonary bypass (CPB), some patients may require circulatory support. This study examined the role of the phosphodiesterase-III inhibitor, enoximone, in cardiac surgery. Eighty patients selected by chance were allocated randomly to two groups: 40 patients received enoximone 1.0 mg kg-1 approximately 10 min before weaning from CPB and 40 served as a control group. Additional pharmacological therapy (adrenaline, noradrenaline, nitroglycerin) was given, when necessary, by anaesthetists who were not involved in the study. In addition to standard monitoring, skin capillary blood flow was assessed using a laser Doppler technique before, during and after CPB until 2 h after the end of the operation. In the period after bypass, cardiac index was always significantly greater in the enoximone than in the control group. Systemic and pulmonary vascular resistance were less in the enoximone-treated patients, indicating a reduction in right and left ventricular wall stress. Oxygen consumption in the enoximone patients was significantly greater after CPB, whereas intrapulmonary shunting was comparable in the two groups. In comparison with baseline values, skin capillary blood flow in the enoximone patients was always greater than that in the control group. In comparison with the control patients, significantly fewer enoximone patients needed adrenaline, and in a smaller dose, even 2 h after operation, whereas more enoximone patients required noradrenaline therapy for a short period. We conclude that the use of enoximone before weaning from CPB improved overall cardiac function, reduced the need of catecholaminergic inotropic support, and provided increased organ perfusion up to 2 h after operation.

Adult↗

Endothelin plasma levels in old and young patients during open heart surgery: correlations to cardiopulmonary and endocrinology parameters.

We compared endothelin (ET) plasma levels during and after aortocoronary bypass (CPB) grafting in old and young patients. Correlations to cardiopulmonary parameters and catecholamines were tested. The study included 22 patients (11 aged greater than 70 years and 11 aged less than 55 years). Measurements were performed after induction of anesthesia (baseline), before bypass, during bypass, after patients were weaned off bypass, at the end of operation, and after 4-h intensive care (IC) treatment. ET [radioimmunoassay (RIA) technique] and catecholamines [high pressure liquid chromatography (HPLC) technique] plasma levels were determined from arterial blood samples; hemodynamics (pulmonary artery catheter), oxygen data, and laser Doppler flow were also monitored. Baseline ET plasma levels were within normal range (young, 3.1 +/- 0.9 pg/ml, old, 4.5 +/- 1.4 pg/ml). Old patients had higher values during the entire investigation period. During CPB ET plasma levels increased to a maximum immediately after patients were weaned off bypass. A significant increase (twofold to baseline) was noted during IC therapy. ET plasma levels did not correlate to catecholamine plasma levels or to hemodynamic or laser Doppler flow parameters. A significant correlation existed between ET plasma levels and oxygen consumption. Monitoring ET plasma levels appears to be of minor value in predicting circulatory changes and assessing surgical stress. Further investigations must elucidate the increase in oxygen consumption and its correlation to ET plasma level.

Aged↗

[Cardiorespiratory and microcirculatory effects following volume replacement using a new hydroxyethyl starch preparation].

Volume therapy is often necessary in cardiac surgery to maintain stable haemodynamics. Various different hydroxyethyl starch (HAES) solutions with different concentrations, mean molecular weights, and degrees of substitution are available for this purpose. In determining the ideal type of volume therapy, not only changes in macrohaemodynamics, but also the influence on microcirculatory blood flow have to be taken into account. The efficacy of a new 10% HAES 130/0.5 solution was studied in cardiac surgery patients in comparison to a standard 10% HAES 200/0.5 preparation. METHODS. In patients scheduled for elective aortocoronary bypass grafting who had a pulmonary capillary wedge pressure (PCWP) of less than 4 mm Hg after induction of anaesthesia, either a new 10% HAES 130/0.5 (n = 15) or a standard 10% HAES 200/0.5 solution (n = 15) was infused to double the reduced PCWP; 15 patients without volume therapy served as controls (n = 15). A two-channel laser Doppler skin blood-flux monitor was used to evaluate microcirculatory alterations. Measurements of laser Doppler flux (LDF) was simultaneously performed at the patient's forehead and forearm before and after volume infusion as well as during and after cardiopulmonary bypass (CPB). In addition, changes in gross haemodynamics were documented using a pulmonary artery catheter. Plasma viscosity and various laboratory parameters, including calculation of intrapulmonary right-to-left shunting (Qs/Qt), were also measured. RESULTS. Cardiac index (CI) increased in both volume groups (HAES 130: max. +38%; HAES 200: +55%). The increases in PCWP and CI were maintained at 40 min after volume infusion only in the HAES 200 patients. Systemic vascular resistance (SVR) decreased most markedly after infusion of HAES 200 (-34%; HAES 130: -18%). No further differences in gross haemodynamics could be seen after CPB. Plasma viscosity and colloid osmotic pressure increased in both HAES groups without significant differences. During the entire investigation period, pulmonary gas exchange (paO2) and Qs/Qt did not differ between the groups. Infusion of both HAES solutions resulted in an increase in LDF that was most pronounced after infusion of HAES 200 (forehead LDF: +81%; HAES 130: +18%) and was evident in the post-bypass period only in these patients (LDF: HAES 200: +82%; HAES 130: -20%; control: -43%). No correlation between LDF values and the other haemodynamic and laboratory parameters could be demonstrated. CONCLUSION. The improvement in macrohaemodynamics was of shorter duration after infusion of the new HAES 130 solution than after standard HAES 200. Volume replacement with HAES 200 resulted in an increase in microcirculatory blood flow that was more pronounced and of longer duration than in the HAES 130 patients. Thus, HAES 130 seems to be less effective than HAES 200 for volume replacement; HAES 200 should be preferred in patients undergoing cardiac surgery.

Cardiac Surgical Procedures↗

[The Nakayama technique of shunt creation for chronic hemodialysis. Experience, complications and possibilities of their removal].

The Brescia-Cimino fistula is carried out as an end-to-end anastomosis for mechanical flow reasons. The Nakayama anastomosis in the upper plexus anesthesia is carried out as a fast and simple apparatus method. Between 1973 and June 1977, 114 Nakayama anastomoses were performed in 80 patients. Till June 1977, 61 were still usable. Time and cause of occlusion were analyzed. Early occlusion (within 30 days) was mainly caused by faulty operation. Late occlusion (within 4 months) was mainly caused by thrombosis at the tantalum ring and improper usage. Shunt occlusion was remedied by a new connection on the same or on the other arm, by vein replantation, or by construction of a vein loop. The arteria femoralis was placed in subcutaneous position when blood vessel conditions were unfavorable. Tests with Spark's prosthesis and autologous vein transplantation produced no usable vessels.

Arm↗