Cardiopulmonary bypass (CPB) involves the use of either an occlusive roller pump or centrifugal pump. Damage to blood elements, including haemolysis, may arise from occlusion when using a roller pump; the appropriate degree of occlusion has not yet been determined scientifically. Centrifugal and nonocclusive roller pumps are reputed to reduce haemolysis. The objective of this study was to compare haemolysis caused by a standard roller pump with a dynamically set nonocclusive roller pump and with a centrifugal pump. We prospectively randomized 60 patients undergoing routine coronary artery surgery into three groups: standard roller pump (STD, n = 20), dynamically set roller pump (DYN, n = 20), or centrifugal pump (CEN, n = 20). The level of plasma free haemoglobin (FHb) was measured preoperatively, and the rate of formation of FHb (in mg/dl/min) was determined at the end of the ischaemic phase and at the end of CPB. Cardiotomy suction blood was isolated for the ischaemic phase and returned before the end of CPB. It was found that there were no differences between the groups in demographic or operative variables. The rate of formation of FHb at the end of the ischaemic phase was similar for all groups (STD 0.108 +/- 0.10, DYN 0.117 +/- 0.08, CEN 0.129 +/- 0.07). At the end of CPB, after return of the cardiotomy suction blood, there was a significant (< 0.001) increase in the rate of formation of FHb in all groups. The increase was similar for each of the groups (STD 0.424 +/- 0.17, DYN 0.481 +/- 0.20, CEN 0.471 +/- 0.18). We conclude that the rates of haemolysis are similar for each of the pump types, and no benefit is conferred by the use of either a dynamically set roller pump or a centrifugal pump compared with the standard roller pump. The return of the cardiotomy suction blood to the circulation is the principal source of plasma free haemoglobin.

No abstract

1. Resting carotid baroreflex sensitivity and blood pressure responses to standardized conditions of rest and exercise were measured in 17 borderline hypertensive males and 12 normotensive males. 2. The borderline hypertensive group had significantly higher systolic and diastolic blood pressures during orthostatic rest and isometric handgrip exercise and higher systolic blood pressure during supine rest and submaximum and maximum treadmill exercise. 3. The borderline hypertensive group had an attenuation of baroreflex sensitivity compared with the normotensive group. Resting baroreflex sensitivity was significantly correlated with absolute systolic blood pressure during supine rest, orthostatic rest, isometric handgrip exercise and submaximum treadmill exercise. 4. The results indicate that blood pressure is regulated at a significantly higher level during rest and exercise in borderline hypertension and is associated with reduced baroreflex sensitivity measured at supine rest.

This study compares prospectively the cardiovascular and catecholamine responses to central venous and pulmonary artery catheterization before and after induction of general anaesthesia. Twenty patients for elective coronary artery surgery were randomized into two groups. One group had central venous and pulmonary artery catheterization performed awake using local anaesthesia. The other group had these catheters inserted following induction of general anesthaesia. In all patients heart rate, arterial blood pressure, ST segment analysis and epinephrine and norepinephrine

No abstract