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Biomedical subjects

D Himpe

Publications and source records attributed to D Himpe.

12 recordsLinked to original sources
PubMed2003

Adding lactate to the prime solution during hypothermic cardiopulmonary bypass: a quantitative acid-base analysis.

BACKGROUND: The effect of adding lactate to the cardiopulmonary bypass (CPB) prime was investigated using Stewart's quantitative acid-base approach. According to this quantitative model, serum pH and bicarbonate are determined by three independent factors: the partial pressure of carbon dioxide (PCO(2)), the total concentration of weak acids (e.g. albumin), and the strong ion difference. The apparent strong ion difference is calculated as the sum of sodium, potassium, magnesium and calcium minus chloride concentrations. The pH decreases with a smaller strong ion difference and vice versa. METHODS: Twenty patients scheduled for coronary surgery were studied prospectively. All patients were treated identically, except for the prime, which either contained lactate or was lactate free. Just before bypass and before coming off bypass, haemoglobin, glucose, plasma osmolality and colloid osmotic pressure were determined; albumin, lactate, sodium, potassium, ionized calcium, magnesium, phosphate, arterial pH, PCO(2), bicarbonate, and base excess were measured for use in Stewart's analysis. RESULTS: Metabolic acidosis had resolved by the end of bypass with the lactated prime. Although the strong ion gap (apparent minus effective strong ion difference) increased significantly in both groups, its composition differed significantly between the groups. The Stewart technique detected polyanionic gelatin as a weak acid component contributing to the unidentified anion fraction. Colloid osmotic pressure was maintained in both groups. CONCLUSION: Exogenous lactate attenuates acidosis related to CPB. The oncotic and weak acid deficits produced by hypoalbuminaemia may be compensated for temporarily during CPB by polyanionic synthetic colloids such as succinylated gelatin.

Acid-Base Equilibrium↗
PubMed2003

Colloids versus crystalloids as priming solutions for cardiopulmonary bypass: a meta-analysis of prospective, randomised clinical trials.

Using Cochrane methodology a review was performed of prospective randomized clinical trials comparing colloidal pump priming solutions for cardiopulmonary bypass. Dextrans were not considered. Database searches from 1966 through December 2002 delivered 265 articles. Seventeen studies finally met the eligibility criteria involving 997 patients. Summary odds ratio estimates from the 5 studies reporting mortality were 1.46 (n = 326; 95%-Confidence-Interval: .55 to 3.85; p = .49) for crystalloids against colloids and .74 (n = 150; 95%-Confidence-Interval: .17 to 3.36; p = .49) for albumin versus synthetic colloids. Most commonly used outcome measures further included postoperative blood loss, platelet-count, fluid-balance and, colloid osmotic pressures from which Standardized Mean Differences (SMD) and their 95%-Confidence-Interval (95%CI) were extracted. Colloids produced significantly higher oncotic pressures and less positive fluid-balances. Although across 9 studies postoperative bleeding between colloids and crystalloids did not differ (n = 663; SMD: -.03, 95%CI: -.18 to .12; p = .69), platelet counts significantly favoured crystalloids (n = 465; SMD: -.42; 95%CI: -.68 to -.16; p = .00). However, compared to albumin platelet counts were significantly disfavoured only by starches (n = 321; SMD: -.55; 95%CI: -.77 to -.32; p = .00). To conclude, using mere crystalloids produced more pronounced positive fluid balances and their avoidance as a single pump-prime component can be suggested. Since albumin is not necessarily associated with better outcomes and is more expensive, it is hard to continue its use. However, there is still insufficient evidence available to allow definitive conclusions.

Cardiopulmonary Bypass↗
PubMed2001

Safety first--five years later. Belgian standards for patient safety in anaesthesia revisited.

Belgian Standards for Patient Safety in Anaesthesia, established in 1989 by a joint effort of the Belgian Professional Association of Anesthesiologists and the Belgian Scientific Society of Anaesthesia and Resuscitation, were intended to be fully implemented within hospital practice by January 1st, 1995. In order to gather follow-up data with regard to this deadline, the Professional Association of Anesthesiologists conducted a survey in 1995: a questionnaire was circulated to all Belgian anaesthetists in order to evaluate the extent to which these guidelines had been implemented in clinical practice and to determine the areas in which residual noncompliance remained. 71% of responders complied with the safety guidelines as far as monitoring in the operating room was concerned. Nursing help was available to 95% of the responders. Concerning the requirement for continuous attendance during anaesthesia by a doctor anaesthetist, some questions remain: although the principle was accepted by 53% of responders, the practical consequences are such that flexibility in working conditions is hampered by the obligation to stay at the side of the anaesthetised patient, under all circumstances. The survey reveals that 65% of responders do not totally comply with this guideline of continuous attendance by a doctor. Many of them propose professional assistance by nursing staff with a specific education and training in anaesthesia.

Anesthesiology↗
PubMed1996

Clinical evaluation of the oxygenation capacity and controllability of 15 commercially available membrane oxygenators during alpha-stat regulated hypothermic cardiopulmonary bypass.

Oxygenation performance was tested in 15 membrane oxygenators by calculating the resistance for oxygenation (R) and the calculation of oxygen transferred versus FiO2. The clinical data reveal that the SARNS Turbo 440 (36.7-51.9%), the AFFINITY (37.2-50.1%) and the HF 5400 (37.5-52.3%) are the oxygenators with the lowest FiO2 settings for comparable amounts of oxygen transferred during hypothermia and during normothermia followed by MAXIMA Plus (39.1-55.8%), MAXIMA Plus PRF (39.1-56.2%), CAPIOX SX 18 (39.7-61.2%), MONOLYTH (43.0-61.3%), OXIM 11-34 (44.1-63.9%), COBE Duo (44.7-64.9%), COBE Optima (47.4-66.4%), COMPACTFLO (48.3-65.3%), SAFE II (49.0-67.6%), UNIVOX (49.8-71.3%), MAXIMA (50.2-70.1%) and the CM 50 (58.6-77.0%). Similar results were found by calculation of R. HF 5400 (2.41-1.87 mmHg/min/ml O2), AFFINITY (2.63-1.87 mmHg/min/ml O2). OXIM II-34 (2.72-2.45 mmHg/min/ml O2), MAXIMA Plus PRF (2.75-2.07 mmHg/min/ ml O2), COBE Optima (2.83-2.13 mmHg/min/ml O2), UNIVOX (2.84-2.17 mmHg/min/ml O2), MONOLYTH (2.89-2.24 mmHg/min/ml O2), SARNS Turbo 440 (3.03-2.12 mmHg/min/ml O2), MAXIMA Plus (3.09-2.28 mmHg/min/ml O2), SAFE 11 (3.19-2.50 mmHg/min/ml O2), CAPIOX SX 18 (3.27-2.44 mmHg/ min/ml O2), COMPACTFLO (3.41-2.50 mmHg/min/ml O2), MAXIMA (3.53-2.72 mmHg/min/ml O2), COBE Duo (3.57-2.71 mmHg/min/ml O2) and the CM 50 (3.53-2.72 mmHg/min/ml O2). As a measure of controllability of oxygenation, the coefficient of variation on the FiO2 ordered on the normothermic blood samples was used, giving as a result CAPIOX SX 18 (2.9-2.5%), AFFINITY (3.6-3.5%), COBE Duo (4.3-2.9%), HF 5400 (5.7-4.7%), MAXIMA Plus (8.1-5.4%), COMPACTFLO (8.2-5.0%), MONOLYTH (8.3-4.0%), MAXIMA (8.7-3.4%), COBE Optima (9.6-6.8%), SARNS Turbo 440 (10.1-7.3%), MAXIMA Plus PRF (10.9-8.7%), CM 50 (11.9-2.4%), UNIVOX (13.3-8.9%), OXIM 11-34 (15.5-17.3%) and the SAFE II (16.1-9.8%). The low FiO2 settings and the lower resistance for oxygenation are an indication of the reserve capacity of the oxygenators whose importance is proven by clinical data of emergency perfusions on patients under full resuscitation.

Aged↗
PubMed1991

Priming solutions for cardiopulmonary bypass: comparison of three colloids.

The present study was designed to compare the differences in the clinical effects of three colloidal solutions, albumin, urea-linked gelatin, and succinyl-linked gelatin, when used as priming fluids for cardiopulmonary bypass (CPB) under alpha-stat conditions. A consecutive series of 105 patients scheduled for cardiac surgery were randomized into three identically managed groups, except for the CPB prime. Variables relating to acid-base status, oncotic activity, metabolism, coagulation, and postoperative evaluation were measured. Marked differences in acid-base status, colloid osmotic pressure, additional prime requirements, blood lactate, urine output, and the need for buffer solutions occurred among groups, with the succinyl-linked gelatin group having better results than the other groups. Changes in hemodynamics, oxygen consumption, and blood-glucose levels during CPB did not vary among groups. There were also no important intergroup differences in hematologic and clotting variables or postoperative parameters such as blood loss or use of blood products. Electrolyte changes were similar except for a significant increase in ionized calcium that occurred in the urea-linked gelatin group after bypass. The results indicate that succinyl-linked gelatin is an adequate and safe alternative to human albumin for use as a colloid during CPB under alpha-stat conditions.

Acid-Base Equilibrium↗
PubMed1991

Predictive value of coagulation testing in cardiopulmonary bypass surgery.

Severe postoperative bleeding in cardiopulmonary bypass surgery is still a major problem. One hundred and seven patients undergoing uncomplicated coronary artery bypass grafting (CABG) were studied. Two groups were formed according to the patients' 24 hours postoperative mediastinal blood loss. Patients in group I (n = 70) had blood loss less than 1000 ml and patients in group II (n = 33) had blood loss over 1000 ml. Between the two groups, there were no differences in age, male-female ratio, number of grafts, by pass-time or heparin-protamine dose. Coagulation testing: APTT (Activated Partial Thromboplastin Time), PT (Prothrombin Time), fibrinogen, D-dim. (D-dimers), bleeding time, MPV (mean platelet volume) and platelet count, was done preoperatively (T0), immediately postoperatively (T1), 6 hours postoperatively (T2). We were especially interested in the predictive value of hemostatic parameters at T0 and T1. We found a slight but statistically negative correlation between the platelet count (T0 and T1) and the postoperative blood loss.

Blood Coagulation Tests↗
PubMed1990

New approach to systemic vascular resistance calculation and clinical decision making.

The Systemic Vascular Resistance (SVR) obtained by invasive monitoring is frequently used in critical-care medicine to guide the use of vasodilators or vasopressors. This study was designed to illustrate the importance of distinguishing between vascular and blood viscosity components when interpreting particular SVR values. The calculation of a corrected SVR is proposed to provide a "standard" C-SVR that gives a better picture of the true vascular changes. 100 patients were studied during hypothermic cardiopulmonary bypass (CPB) in order to illustrate the importance of this concept. The regular SVR was repeatedly measured and compared with the C-SVR. At all times the uncorrected SVR was significantly lower than the corrected C-SVR, which underlines the importance of calculating this parameter.

Blood Viscosity↗