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Effects of Nitroglycerin on Central Haemodynamics and V A /Q Distribution Early after Coronary Bypass Surgery
Author(s) -
Lindskog E. Anjou,
Broman L.,
Holmgren A.
Publication year - 1982
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.1399-6576.1982.tb01805.x
Subject(s) - medicine , nitroglycerin (drug) , hemodynamics , bypass surgery , coronary artery bypass surgery , anesthesia , derivation , cardiology , distribution (mathematics) , artery , mathematical analysis , mathematics
Central haemodynamics and ventilation‐perfusion (V̇ A A/Q̇) distributions were studied in nine patients, 21 h after coronary bypass surgery, before and during nitroglycerin (TNG) infusion. V̇ A /Q̇ distributions were established with the multiple inert gas elimination technique of Wagner and West. Administration of TNG resulted in a decrease in mean arterial pressure, a slight reduction in cardiac output and stroke volume and a significant increase in heart rate, possibly explained by an initial relative hypovolaemia. Pulmonary arterial pressures and filling pressures for the right and left ventricles decreased significantly. There was a significant reduction in Pao 2 and an increase in venous admixture (Q̇ VA /Q̇ T ) from 11.3 to 16.5% of cardiac output. This was mainly due to an initial SF 6 ‐shunt of 6.4% increasing to 12.8%. Only 3.5% of cardiac output during TNG was due to perfusion of hypoventilated areas. The mean for the control Q̇‐distribution was 0.88 with a mean log s.d. of ±1.14, indicating V̇ A /Q̇‐mismatch and did not change significantly. The reduction of pressures in the pulmonary vascular bed was accompanied by increased ventilation of areas with high V̇ A /Q̇.