Hemodynamic evaluation of the Monostrut and spherical disc Bj?rk-Shiley aortic valve prosthesis with Doppler echocardiography.

A Doppler echocardiographic study was performed to assess whether the Monostrut model of the Bj?rk-Shiley valve (Shiley, Inc., Irvine, Calif.) had an improved hemodynamic performance in comparison with the spherical disc model in the aortic position. Twenty retrospectively randomly selected patients were studied, 10 with each valve type. Within each valve type two sizes of valve were studied, 21 and 23 mm. The two groups were comparable with respect to age, postoperative time, fractional shortening, New York Heart Association functional class preoperatively, and body surface area. Pulsed and continuous wave Doppler measurements were recorded at rest. Continuous wave Doppler recordings were performed every 2 minutes after exercise with supine bicycle ergometry until 10 minutes after exercise. Peak and mean gradients across the aortic valve prostheses were estimated. Both groups achieved a significant and comparable rise in heart rate with exercise. The mean gradients +/- standard error of the mean at rest and 2 minutes after exercise were 19.7 +/- 1.9 mm Hg and 30.9 +/- 2.2 mm Hg, respectively in the spherical disc group compared with 14.9 +/- 1.1 mm Hg and 23.6 +/- 1.7 mm Hg in the Monostrut group (p < 0.05 and p < 0.025, respectively). Peak transvalvular gradient at rest was 30.7 +/- 2.7 mm Hg in the spherical group compared with 23.9 +/- 1.9 mm Hg in the Monostrut group (p < 0.05). We conclude that the Monostrut Bj?rk-Shiley valve prosthesis has better hemodynamic performance than the spherical disc model in the aortic position.     

Factors affecting the binding of tricyclic tranquillizers and antidepressants to human serum albumin.

The linear free energy-related model for structure activity relations developed by Hansch & Fujita (1964) has been used to correlate the binding of tricylic tranquillizers and antidepressants to human serum albumin (HSA) with hydrophobic and electronic parameters. The parameters chosen being the chromatographic parameter (Rm) and the affinity of charge transfer complex formation (kc). The relative importance of these factors has been assessed by linear and multiple linear regression analysis. Results show that the major factor in binding is electronic with only a minor contribution from the hydrophobic parameter.     

Ferromagnetic materials in patients: detection before MR imaging

A number of surgical clips and other metallic materials embedded within patients have ferromagnetic properties that present a potential hazard when in the strong fields associated with magnetic resonance imaging. Several types of magnetometers and metal detectors were investigated as possible pre-imaging screening devices. The sensitivities and costs of these devices are given.     

The impact on work-related stress of mental health teams following team-based learning on clinical risk management

Risk management is viewed as a systematic process based on multiprofessional and multi-agency decision-making. A learning pack was developed as part of a team-based learning project aiming to encourage and develop collaborative working practice. This brought different professionals and agencies working in mental health together to learn. There is little doubt that mental health practice is a source of stress for practitioners. Apart from the stress associated with managing 'risky' situations, risk management is also a relatively new concept. This can increase stress around ability to cope, both on an individual practitioner level and in teams. This article reports the impact that the learning pack had on team members' stress, specifically work-related stress. A range of scales were used to measure change in stress and results demonstrated reduced work-related pressure in a number of areas following the learning. The implications for team learning in relation to clinical risk management are discussed in light of the findings.     

Total parenteral feeding in infants using peripheral veins

Fifteen infants with life-threatening gastrointestinal anomalies received total parenteral feeding for periods ranging from 10 to 54 days; their ages ranged from one day to 5 months. The solutions were administered through peripheral veins. All patients gained weight during the period of observation and no cases of septicaemia were encountered.