Perfusion
-
The aim of this study was to monitor the metabolism and blood flow in the interstitium of the skeletal muscle during cardiac surgery with cardiopulmonary bypass (CPB) and in the early postoperative period by means of microdialysis and to compare metabolic changes during CPB at normothermia (NT) and hypothermia (HT). Surgical revascularization using CPB was performed in 50 patients, 25 patients (group HT) were operated using hypothermic CPB, 25 (group NT) using normothermic CPB. Interstitial microdialysis was performed by two CMA 60 probes (CMA Microdialysis AB, Solna, Sweden) inserted into the patient's deltoid muscle. ⋯ The results showed dynamic changes in the interstitial concentrations of glucose, urea, glycerol and lactate, which depend on the phase of the surgery in the CPB and early postoperative phase in the both groups of patients. Higher tissue perfusion of the skeletal muscle was noted in those patients operated on in normothermia. The dynamics of the concentration changes of these substances in the interstitium of the skeletal muscle has been proven to be caused by both the metabolic activity of the tissue and by the blood flow through the interstitium of the muscle.
-
To investigate the time course of fluid extravasation during cardiopulmonary bypass (CPB), we measured the peripheral tissue thickness (TT) by A-mode ultrasound in 34 patients undergoing elective cardiac surgery. TT of the forehead was determined by a handheld A-mode ultrasound device and 10 MHz Transducer at nine defined intervals, from the night before surgery until the first postoperative day. Mean calculated loss of 1700 +/- 40 mL (SEM) water during the fasting period resulted in a significant reduction of TT by 0.28 +/- 0.03 mm. ⋯ At discharge from ICU, negative fluid regimen resulted in a balance of -127 +/- 146 mL whereas TT declined significantly to +0.16 +/- 0.09 mm compared to baseline. Dehydration due to fasting and the marked interstitial fluid extravasation during CPB could be detected by the changes of the peripheral TT. We conclude that parts of the fluid load during CPB are shifted from the intravascular compartment to the interstitial space in a time-dependent manner.
-
Clinical Trial Controlled Clinical Trial
Selection of optimal quantity of hydroxyethyl starch in the cardiopulmonary bypass prime.
Ringer's solution prime reduces colloid osmotic pressure and causes edema during cardiopulmonary bypass, while hydroxyethyl starch (HES) can be used to attenuate this effect. Fifty patients were classified into five equal groups: Group I (preoperative patients) is the control group and the other four groups (II, III, IV, V) received different volume ratios of Ringer's solution to HES (1:0, 2:1, 1:2, 0:1, respectively). ⋯ The results showed a reduction in interstitial fluid (ISF) expansion, changes in blood rheologic properties with the increase in HES quantity and shorter ventilation and recovery times in Groups IV and V. We concluded that the optimal HES quantity in the prime is two thirds, which insures an 85% reduction of ISF relative to Group II, shorter ventilation and recovery times and avoidance of the hazards of high levels of HES.
-
Comparative Study
Argatroban as an alternative to heparin in extracorporeal membrane oxygenation circuits.
We investigated the anticoagulant effects of argatroban, a direct thrombin inhibitor, versus heparin in extracorporeal membrane oxygenation (ECMO) circuits. Three sham circuits were prepared according to our hospital's standard practice and run for six hours simultaneously. Two circuits were anticoagulated with argatroban (one with heparin in the wet prime and one without). ⋯ Thrombin generation was decreased in circuits anticoagulated with argatroban versus heparin, despite aPTTs being less prolonged. These results suggest that argatroban may be more efficacious than heparin for anticoagulation in ECMO. Additional studies are warranted to further evaluate argatroban in this setting.
-
Since April 1988, we have been able to offer extracorporeal membrane oxygenation (ECMO) to patients who are either failing ventilation or who need cardiopulmonary support following cardiac surgery. During this time, we have supported 211 patients, the majority of whom have been supported with the Avecor (Affinity, Avecor Cardiovascular Inc., Minneapolis, MN, USA) spiral wound silicone-membrane oxygenator. Microporous hollow-fibre oxygenators have been used (18%) at our center. ⋯ From July 2000, we have used the QuadroxD oxygenator for our patients requiring ECMO support. This has been in patients with weights ranging from 2.16-51.0 kg (n = 23), with the longest support being for 1119 hours. This new technology has enabled us to utilize a single device for all patient sizes, so we now have an ECMO circuit set up at all times, minimizing the time required for support to be available, potentially improving survivor morbidity.