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M S Bayfield

Publications and source records attributed to M S Bayfield.

5 recordsLinked to original sources
PubMed2005

Supported and unsupported arm exercise capacity following lung volume reduction surgery: a pilot study.

STUDY OBJECTIVES: Lung volume reduction surgery (LVRS) has been shown to improve lung function, leg exercise capacity and quality of life in subjects with severe COPD. This is the first study to examine the effect of LVRS on supported and unsupported arm exercise capacity. DESIGN: Eight subjects with COPD (% pred FEV1 +/- SD = 31.1 +/- 9.8%) completed testing. At baseline (T1), after eight weeks pulmonary rehabilitation (T2) and four months after LVRS (T3), each subject had tests of lung function, and performed three symptom-limited exercise tests to peak work capacity: supported arm exercise (SAE), unsupported arm exercise (UAE) and leg exercise (LE). MEASUREMENTS: The FEV1 (% pred) increased from 27.8 +/- 7.4 (mean +/- SD) at T2 to 36.3 +/- 7.1 at T3 (P < 0.05). Peak oxygen consumption (VO2) remained similar from T1 to T2 for SAE, UAE and LE (all P = 1.0) but increased from T2 to T3 (P < 0.05) (SAE: T2 = 0.59 +/- 0.2 L/min, T3 = 0.72 +/- 0.1 L/min; UAE: T2 = 0.45 +/- 0.1 L/min, T3 = 0.54 +/- 0.1 L/min; LE: T2 = 0.68 +/- 0.2 L/min, T3 = 0.81 +/- 0.2 L/min). The ratio of end-expiratory lung volume to total lung capacity was reduced at peak SAE and LE from T2 to T3 (P < 0.01) (SAE: T2 = 81 +/- 4.0%, T3 = 76 +/- 2.7%; LE: T2 = 81 +/- 5.1%, T3 = 75 +/- 3.6%). CONCLUSION: There was a significant increase in SAE and UAE capacity following LVRS. Dynamic hyperinflation was reduced during SAE following LVRS.

Aged↗
PubMed2000

Composite graft replacement of the aortic root after previous cardiac surgery: a 20-year experience.

BACKGROUND: An aging population and prolonged survival of patients after cardiac operations has meant that composite aortic root replacement after previous cardiac operation is being performed with increasing frequency. METHODS: From January 1979 to July 1999, 32 patients underwent "reoperative" composite replacement of the aortic root at our institution. Previous operations were 16 aortic valve replacement, 9 coronary artery bypass grafting, 5 repair aortic dissection, and 7 others. Indications for operation included ascending aortic aneurysm in 16 patients, ascending aortic dissections in 10 patients, and other in 6 patients. RESULTS: The unit elective mortality was 3 of 26 (11.5%). One surgeon's elective mortality was 1 of 22 (4.6%). The unit emergent mortality was 6 of 6 (100%). There has been one late death. Morbidity was low. CONCLUSIONS: Reoperative aortic root replacement is a technically demanding procedure, but expertise in the area achieves low elective mortality. Consideration should be given to aortic root replacement at the initial procedure. Close follow-up of postcardiac operation patients is necessary to proceed with elective aortic root replacement if indicated. Emergent presentation in the reoperative setting has a very poor prognosis.

Adult↗
PubMed1997

Deoxygenated blood minimizes adherence of sonicated albumin microbubbles during cardioplegic arrest and after blood reperfusion: experimental and clinical observations with myocardial contrast echocardiography.

Both administration of cardioplegic solution and blood reperfusion result in endothelial dysfunction. The transit rate of albumin microbubbles during myocardial contrast echocardiography may reflect endothelial injury. Accordingly, we performed myocardial contrast echocardiography in 12 dogs undergoing cardiopulmonary bypass and measured the myocardial transit rate of microbubbles injected into the aortic root during delivery of cardioplegic solutions containing arterial and venous blood and delivery of pure crystalloid cardioplegic solution. The myocardial transit rate of 99mTc-labeled red blood cells was measured and perfusates were sampled for biochemical analysis at each stage. The microbubble transit rate was markedly prolonged during delivery of crystalloid cardioplegic solution and improved significantly during infusion of blood cardioplegic solution (p < 0.001); venous compared with arterial blood in the solution resulted in a greater rate (p < 0.001). The microbubble transit rate did not correlate with pH, oxygen tension or carbon dioxide tension values, or K+ concentration. The red blood cell transit rate remained constant regardless of the cardioplegic perfusate infused. Myocardial contrast echocardiography was also performed in 12 patients undergoing coronary artery bypass who underwent sequential arterial and venous reperfusion after cardioplegic arrest. The microbubble transit rate was faster with venous than arterial blood reperfusion (p = 0.01), although this gain was diminished when arterial blood reperfusion preceded venous blood reperfusion (p = 0.05). Our results indicate that endothelial dysfunction after cardioplegic arrest may be ameliorated by reperfusion with venous rather than arterial blood.

Albumins↗
PubMed1995

Reducing bleeding after replacement of the aortic root.

Bleeding after replacement of the aortic root continues to be a major surgical problem. We detail two reliable methods, which are quick and simple to perform, that minimize surgical bleeding after aortic root replacement.

Anastomosis, Surgical↗