Effects of thoracic epidural analgesia on pulmonary function after coronary artery bypass surgery

• Published in: European journal of cardio-thoracic surgery 1996, Vol.10 (10), p.859-865
• Main Authors: Stenseth, R, Bjella, L, Berg, E M, Christensen, O, Levang, O W, Gisvold, S E
• Format: Article
• Language: English
• Subjects: Adult; Analgesia, Epidural; Anesthesia Recovery Period; Anesthesia, General; Coronary Artery Bypass; Dose-Response Relationship, Drug; Fentanyl; Humans; Lung - blood supply; Lung Volume Measurements; Male; Middle Aged; Pain, Postoperative - drug therapy; Pain, Postoperative - physiopathology; Regional Blood Flow - drug effects
• ISSN: 1010-7940; 1873-734X
• DOI: 10.1016/S1010-7940(96)80311-3

OBJECTIVE: A substantial reduction in lung volumes and pulmonaryfunction follows cardiac surgery. Pain may prevent effective breathing andcoughing, and as thoracic epidural analgesia may reduce postoperative pain,we investigated the effect of epidural analgesia on pulmonary function.METHODS: Fifty-four male patients, under 65 years and with an ejectionfraction of more than 0.5, were randomized into two groups: a control groupreceiving high-dose fentanyl anaesthesia and an epidural group receivinglow-dose fentanyl anaesthesia + thoracic epidural analgesia. Time toawakening and time to extubation were recorded. Further, spirometric data,arterial oxygenation, pulmonary shunt, haemodynamics, use of vasoactivedrugs and fluid balance were followed for up to 6 days postoperatively.RESULTS: Patients with low-dose fentanyl and epidural analgesia awoke (1.6vs 3.6 h) and were extubated (5.4 vs 10.8 h) significantly earlier thancontrol group patients. A 50-70% reduction in forced vital capacity, forcedexpiratory volume in 1 s (FEV1.0) and peak expiratory flow rate (PEFR) wasseen after surgery, but higher FEV1.0 and PEFR on days 2 and 3 were seen inthe epidural group than in the control group. Pulmonary shunt andalveolo-arterial oxygen difference increased similarly in both groups,whereas oxygen delivery and mixed venous oxygen saturation were higher inthe epidural group. Epidural analgesia gave better control of thepostoperative hyperdynamic circulation. CONCLUSIONS: Thoracic epiduralanalgesia yields a slight, but significant, improvement in pulmonaryfunction, most likely due to a more profound postoperative analgesia.