A novel hydroxyethyl starch (Voluven) for effective perioperative plasma volume substitution in cardiac surgery.

PURPOSE: To compare the new hydroxyethyl starch HES 130/0.4 (Voluven) and the standard HES 200/0.5 (pentastarch) regarding effectiveness for plasma volume substitution and safety of large volumes in heart surgery. METHODS: Fifty-nine patients scheduled for coronary artery bypass grafting were enrolled in a prospective, randomised, double-blind, parallel-group, multicentre, clinical, phase III study. Hydroxyethyl starch was used as the exclusive artificial colloid for acute normovolemic hemodilution, priming of the heart lung machine, and for intra- and postoperative plasma volume substitution from induction of anesthesia until 16 hr after the end of surgery. Efficacy was evaluated by comparing the amount of colloid infused, hemodynamics, and colloid osmotic pressure (COP). Safety endpoints were blood loss, the use of allogeneic blood products, coagulation variables, and adverse events. RESULTS: Effectiveness, as assessed by the total amount of infused HES volumes within the treatment period, was similar between HES 130/0.4 and HES 200/0.5 (2,550 mL +/- 561 mL vs 2,466 mL +/- 516 mL). Also, no differences were found for the use of other colloids (pasteurised plasma), hemodynamics, and COP In HES 130/0.4 patients, the postoperative increase of von-Willebrand factor (vWF) was higher (P < 0.01), blood loss was lower, and less packed red blood cells were transfused. CONCLUSION: Hydroxyethyl starch 130/0.4 is an effective plasma volume expander in heart surgery and may be used as the sole artificial colloid to cover the perioperative period. We found a reduced influence of HES 130/0.4 on the physiologic postoperative increase of vWF.

Comparison of three plasma expanders used as priming fluids in cardiopulmonary bypass patients.

Ten per cent low molecular weight hydroxyethyl starch is a plasma substitute only recently used as priming solution in an extracorporeal circuit, in contrast to human albumin and gelatin. To evaluate the effect of priming solutions on haemodynamics and colloid osmotic pressure, we studied 36 patients elected for cardiopulmonary bypass (CPB). They were randomly assigned to 2.5% hydroxyethyl starch, 3% gelatin or 4% human albumin priming solution. Total blood loss (perioperative + intensive care unit period) was higher in the gelatin group than in the albumin and hydroxyethyl starch groups. During CPB, the colloid osmotic pressure was best preserved in the gelatin group, although no excessively low colloid osmotic pressures were measured in the other two groups. Due to the extended half-life and the additional postoperative colloid administration, the hydroxyethyl starch group had a higher colloid osmotic pressure in the postoperative phase. We conclude that, next to human albumin, 2.5% hydroxyethyl starch is a safe CPB priming solution additive and is effective as plasma substitute. Its somewhat longer half-life requires adaptation of the routine protocol for transfusion of colloids and blood products.

Hemostatic effects of three colloid plasma substitutes for priming solution in cardiopulmonary bypass.

OBJECTIVE: To evaluate the effects on hemostasis of three different plasma substitutes with special reference to a newly developed hydroxyethyl starch used as priming solution in an extracorporeal circuit as well as peri- and postoperative infusion fluid, we studied 36 patients randomly assigned to one of three groups, undergoing coronary artery bypass grafting. METHODS: The compositions of the priming solutions were: 2.5% hydroxyethyl starch; 3% gelatin; and 4% human albumin. Platelet function tests and clotting assays were performed on blood samples collected during and after cardiopulmonary bypass. RESULTS: We found that plasma von Willebrand Factor remained higher in the human albumin group. Hydroxyethyl starch preserved platelet agglutination as well as human albumin, whereas platelet aggregation induced by adenosine 5'-di phosphate (ADP) proved to be similarly affected during cardiopulmonary bypass in the three study groups. Prolongation of the in vitro bleeding constant during the bypass period and subsequent partial recovery showed an affected platelet function in all groups during cardiopulmonary bypass. The clotting times, activated partial thromboplastin time and prothrombin time were similar in the three groups. Blood loss, peri- and postoperatively, showed also no differences. Hydroxyethyl starch appeared most cost-effective as priming solution in an extracorporeal circuit. CONCLUSIONS: We conclude that, with human albumin the golden standard, 2.5% hydroxyethyl starch is a suitable colloid plasma substitute to be used as priming solution in an extracorporeal circuit as well as peri- and postoperative infusion fluid, reasonably well maintaining hemostasis.

Effects of hypothermic cardiopulmonary bypass on the pharmacodynamics and pharmacokinetics of rocuronium.

OBJECTIVE: To study the influence of hypothermic cardiopulmonary bypass (CPB) on the pharmacodynamics and pharmacokinetics of rocuronium. DESIGN: Prospective, descriptive study. SETTING: Operating room at a university hospital. PARTICIPANTS: Ten ASA class III and IV patients, ranging in age from 35 to 75 years, scheduled for elective coronary artery bypass grafting. INTERVENTIONS: Neuromuscular transmission was monitored mechanomyographically. The time course of action of maintenance doses and plasma concentration-response relationships were determined before, during, and after CPB. The plasma concentration decay and renal elimination were studied simultaneously. Plasma and urine concentration of rocuronium were determined by high-performance liquid chromatography. MEASUREMENTS AND MAIN RESULTS: Hypothermic CPB prolonged the duration of action of maintenance doses and coincided with a lower plasma concentration at a twitch response of 5% of control. The duration of action of maintenance doses returned to prehypothermic CPB level after rewarming to a nasopharyngeal temperature of 37 degrees C. The plasma concentration-response relationship did not return to precooling control value, probably owing to persisting peripheral hypothermia. Both the renal elimination of rocuronium and the plasma concentration decay after the last maintenance dose under normothermic conditions resembled values obtained in patients not undergoing hypothermic CPB. CONCLUSIONS: Hypothermic CPB prolongs the duration of action of maintenance doses and alters the plasma concentration-response relationship of rocuronium. These changes may be the result of, on the one hand, an increased sensitivity of the neuromuscular transmission and/or decreased muscle contractility and, on the other hand, the result of a reduced plasma clearance during hypothermia.

Gelatin use impairs platelet adhesion during cardiac surgery.

Artificial colloids based on gelatin are used as plasma expander to replace donor blood products. In laboratory experiments, gelatin reduced both the velocity and extend of platelet agglutination by ristocetin, and only the agglutination velocity by polybrene (p < 0.05). Furthermore, gelatin delayed the in-vitro platelet plug formation under shear-stress in the absence of ADP (p < 0.05), whereas gelatin induced no delay in the presence of ADP. Thus, after induction of vWF release from platelets by polybrene or ADP, platelet function was normal. These results indicate that gelatin affects in particular the functionality of plasma-vWF and partly inhibits platelet adhesion. These negative effects of gelatin on hemostasis were demonstrated in two clinical studies during cardiac surgery. In a randomized study of sixty patients undergoing cardiac surgery, gelatin as prime in the heart-lung machine appeared to result in diminished efficacy of aprotinin on hemostasis, whereas it did not affect hemostasis in non-aprotinin patients. An additional retrospective clinical study showed that only high dose of gelatin affected hemostasis. This suggests a limited role of plasma-vWF and a strong back-up mechanism of platelet-vWF in achieving hemostasis.

Hypothermic cardiopulmonary bypass influences the concentration-response relationship and the biodisposition of rocuronium.

In 10 patients scheduled for elective coronary artery bypass grafting under midazolam-sufentanil anaesthesia, the influence of hypothermia on the plasma concentration-response and biodisposition of rocuronium were investigated. Neuromuscular function was monitored mechanomyographically. Plasma and urine concentrations of rocuronium were determined by high performance liquid chromatography. Hypothermic cardiopulmonary bypass prolonged the duration of action of maintenance doses and altered the plasma concentration-response relationship. The elimination and distribution half-lives, following the last maintenance dose after rewarming, and the urinary excretion of rocuronium were similar to values obtained during normothermia. A diminished hepatic uptake and storage in the liver of rocuronium during hypothermia may explain the more pronounced prolongation of the duration compared to that of other steroidal neuromuscular blocking agents.

Biocompatibility of leukocyte removal filters during leukocyte filtration of cardiopulmonary bypass perfusate.

To evaluate the biocompatibility and the efficacy of leukocyte removal filters, we performed a prospective study by using the cardiopulmonary bypass perfusate taken from the heart-lung machine for 20 patients who underwent cardiac surgery and were randomly divided into four groups according to the filters used. A leukocyte removal filter was installed in the transfusion line while the perfusate was transfused to the patients. No increases of C3a, C5a, elastase, and thromboxane were found during leukocyte filtration by polyester filters (Optima, Sepacell R500, and Pall RC100). Activation of the complement cascade was observed during filtration by the cellulose acetate filter (Cellselect) although the efficacy of the Cellselect filter was evidently higher than that of the polyester filter. These results imply that polyester leukocyte filters are superior to cellulose acetate filters in terms of biocompatibility but have a reduced efficacy. An optimal leukocyte filter providing both high efficacy and biocompatibility has yet to be developed.

Clinical effect of Bretschneider-HTK and St. Thomas cardioplegia on hemodynamic performance after bypass measured using an automatic datalogging database system.

A prospective consecutive study was undertaken to compare the hemodynamic effect of two cardioplegic solutions in CABG patients after bypass, and in relation to aorta occlusion time with the support of a automatic datalogging database. A total of 249 patients were randomized. One group received Bretschneider cardioplegic HTK solution (132 patients, group I) the other group received St. Thomas cardioplegic solution (117 patients, group II). The data was divided in four periods of aortic clamp time: less than or equal to 40 min (group I 26 patients, group II 32 patients); 41-60 min (group I 49 patients, group II 47 patients); 61-80 min (group I 30 patients, group II 29 patients); and greater than 80 minutes (group I 27 pts, group II 9 patients). Anesthesia regime and therapeutic drugs and infusions were given in both groups in similar dosages. Within both groups HR, CO, PAP, PCWP increased after bypass in relation to prebypass values. SVR decreased in both groups by 30%, MAP and PVR decreased only in group I. Between group I and II differences were found in the CI (3.0 vs. 3.3 l/min/m2), MAP (70 vs. 76 mmHg), PMAR (18 vs. 16 mHg), and SVR (827 vs. 954 dyn.sec.cm-5). In significantly more of the patients in group I, sinus rhythm started spontaneously after the release of the aorta clamp (39.5% vs. 20.4%, p less than 0.005). Patients in group I needed temporarily a pacemaker after bypass in 6.3% cases (in 1.1% of patients in group II,). There was no relation of the hemodynamic data in relation to aorta occlusion time within the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Operative risk in old age--an anesthesiological survey of octogenarians.

The anesthesiological records of 138 patients (158 operations), aged 80 years and older, were analysed retrospectively. Ninety-nine patients had received general anesthesia for 115 procedures. Complications and hemodynamic disturbances in this group were studied. Serious hemodynamic changes occurred 31 times in 24 patients. They were readily corrected and did not seem to have had any influence upon the mortality. The anesthesiological risk in our patients was negligible. The mortality in this survey is comparable to that of other series.

The variability of normal male voiding patterns measured by drop spectrometry.

Voidings from 7 healthy men were recorded by means of the urinary drop spectrometer. The voiding patterns were characterised by the trend drop frequency and the distribution of drop time intervals. The variability of these voiding patterns was studied by statistical techniques. The data were grouped for each person. Variances were considerable both within and between groups. Although individual differences in the mean values existed, the groups could not be separated from each other.