We applied a mathematical model to calculate chest wall forces during coughing, in order to determine the force placed upon a sternotomy closure. We conclude that severe coughing may cause wires to untwist. We discuss potential applications of different wire closures based on their characteristics.

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.

In our sheep sternum model, we have quantified the differing rate of cutting through bone of five types of median sternotomy closure techniques. We have controlled for bone variables by testing each closure versus standard closure using paired adjacent bone samples. Peristernal and sternal band closure techniques are significantly superior to standard closure. The use of polyester and figure-of-eight closures requires caution.

suMMARY Between 1970 and 1981, 12% of patients undergoing mitral valve surgery were found to have chordal rupture. Spontaneous or primary rupture accounted for 74-6% of patients (primary group); in the remainder (secondary group) chordal rupture complicated chronic rheumatic valvular disease (8.9%), bacterial endocarditis on both normal (8.5%) and rheumatic valves (4.70/%), ischaemic heart disease (2-3%), acute rheumatic fever (0.5%), and osteogenesis imperfecta (0.5%). Isolated posterior rupture was seen most frequently (54%), with anterior rupture in 36% and rupture of both mitral cusps in 10% of patients. A short symptomatic history of acute mitral regurgitation was rare, occurring in only 4% of patients in either the primary or secondary groups, suggesting that mitral regurgitation due to ruptured chordae is a progressive disease. In contrast to previous reports the clinical presentation did not help to differentiate the aetiology of the chordal rupture.

A 68-year-old male patient had aortic valve replacement for aortic valve endocarditis. The central line (left) position looked abnormal on chest X-ray. Contrast studies confirmed left sided partial anomalous pulmonary venous connection.