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Post‐operative myocardial dysfunction does not affect the physiological response to early mobilization after coronary artery bypass grafting
Author(s) -
KirkebyGarstad I.,
Stenseth R.,
Sellevold O. F. M.
Publication year - 2005
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.2005.00854.x
Subject(s) - medicine , bypass grafting , artery , cardiology , mobilization , affect (linguistics) , grafting , archaeology , history , linguistics , philosophy , chemistry , organic chemistry , polymer
Background: An acute increase in oxygen demand can be compensated for either by increased cardiac index (CI) or increased oxygen extraction, resulting in reduced mixed venous oxygen saturation (S v O 2 ). We tested the hypothesis that post‐operative cardiac dysfunction may explain why oxygen extraction alone is increased during early mobilization after cardiac surgery. Methods: Twenty patients with a pre‐operative ejection fraction > 50% were included in an open prospective observational study comparing the changes in S v O 2 and hemodynamics during mobilizations immediately prior to surgery and on the first post‐operative morning. Results: Mobilization induced an absolute reduction in S v O 2 of 17.7 ± 7.4% pre‐ and 19.0 ± 5.5% post‐operatively (NS). ANOVA for a series of measurements throughout the mobilization sequence identified no different effect on S v O 2 between pre‐ and post‐operative mobilizations ( P = 0.567). The S v O 2 level was reduced post‐operatively resulting in a S v O 2 during standing exercise of 55% before and 49% after the surgery ( P < 0.01). Mobilization increased the heart rate (HR) and decreased the stroke volume index (SVI), leaving CI unchanged. This response was similar pre‐ and post‐operatively (NS). Compared with pre‐operative measurements, CI and HR increased post‐operatively while SVI remained unchanged despite elevated cardiac filling pressures and reduced systemic vascular resistance. The left ventricular stroke work index was reduced, indicating reduced myocardial performance. Conclusion: Myocardial function was reduced on the first morning after coronary artery bypass grafting (CABG), but during post‐operative mobilization this reduction did not significantly influence the changes in CI or S v O 2 .