Changes in Respiratory Mechanics During Cardiac Surgery

• Published in: Anesthesia and analgesia Vol. 96; no. 5; pp. 1280 - 1287
• Main Authors: Babik, Barna, Asztalos, Tibor, Peták, Ferenc, Deák, Zoltán I., Hantos, Zoltán
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD International Anesthesia Research Society 01.05.2003; Lippincott
• Subjects: Adult; Aged; Airway Resistance - physiology; Algorithms; Analysis of Variance; Anesthesia; Anesthesia depending on type of surgery; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Cardiac Surgical Procedures - adverse effects; Cardiopulmonary Bypass - adverse effects; Cohort Studies; Constriction; Extravascular Lung Water - physiology; Female; Humans; Male; Medical sciences; Middle Aged; Monitoring, Intraoperative; Preanesthetic Medication; Respiratory Function Tests; Respiratory Mechanics - physiology; Thoracic and cardiovascular surgery. Cardiopulmonary bypass; Trachea - physiology; Human; Lung disease; Pathophysiology; Respiratory disease; Lung; Cardiovascular disease; General anesthesia; Intraoperative; Coronary heart disease; Cardiopulmonary bypass; Aortocoronary; Bypass; Surgery; Mechanic of breathing; Complication
• ISSN: 0003-2999
• DOI: 10.1213/01.ANE.0000055363.23715.40

We investigated the role of cardiopulmonary bypass (CPB) in compromised lung function associated with cardiac surgery. Low-frequency respiratory impedance (Zrs) was measured in patients undergoing cardiac surgery with (n = 30; CPB group) or without (n = 29; off-pump coronary artery bypass [OPCAB] group) CPB. Another group of CPB patients received dopamine (DA) (n = 12; CPB-DA group). Extravascular lung water was determined in five CPB subjects. Zrs was measured before skin incision and after chest closure. Airway resistance and inertance and tissue damping and elastance were determined from Zrs data. Airway resistance increased in the CPB group (74.9% ± 20.8%;P < 0.05), whereas it did not change in the OPCAB group (11.8% ± 7.9%; not significant) and even decreased in the CPB-DA patients (−40.6% ± 9.2%;P < 0.05). Tissue damping increased in the CPB and OPCAB groups, whereas it remained constant in the CPB-DA patients. Significant increases in elastance were observed in all groups. There was no difference in extravascular lung water before and after CPB, suggesting that edema did not develop. These results indicate a significant and heterogeneous airway narrowing during CPB, which was counteracted by the administration of DA. The mild deterioration in tissue mechanics, reflecting partial closure of the airways, may be a consequence of the anesthesia itself.