Lung function under high thoracic segmental epidural anesthesia with ropivacaine or bupivacaine in patients with severe obstructive pulmonary disease undergoing breast surgery.

Abstract

Because general anesthesia with tracheal intubation can elicit life-threatening bronchospasm in patients with bronchial hyperreactivity, epidural anesthesia is often preferred. However, segmental high thoracic epidural anesthesia (sTEA) causes pulmonary sympathetic and respiratory motor blockade. Whether it can be safely used for chest wall surgery as a primary anesthetic technique in patients with chronic obstructive pulmonary disease or asthma is unclear. Furthermore, ropivacaine supposedly evokes less motor blockade than bupivacaine and might minimize side effects. To test the feasibility of the technique and the hypotheses that (1) sTEA with ropivacaine or bupivacaine does not change lung function and (2) there is no difference between sTEA with ropivacaine or bupivacaine, the authors studied 20 patients with severe chronic obstructive pulmonary disease (forced expiratory volume in 1 s [FEV1] = 52.1 +/- 17.3% of predicted [mean +/- SD]) or asthma who were undergoing breast surgery. In a double-blind, randomized fashion, sTEA was performed with 6.6 +/- 0.5 ml of either ropivacaine, 0.75% (n = 10), or bupivacaine, 0.75% (n = 10). FEV1, vital capacity, FEV1 over vital capacity, spread of analgesia (pin prick), hand and foot skin temperatures, mean arterial pressure, heart rate, and local anesthetic plasma concentrations were measured with patients in the sitting and supine positions before and during sTEA. Segmental high thoracic epidural anesthesia (segmental spread C4-T8 [bupivacaine] and C5-T9 [ropivacaine]) significantly decreased FEV1 from 1.22 +/- 0.54 l (supine) to 1.09 +/- 0.56 l (ropivacaine) and from 1.23 +/- 0.49 l to 1.12 +/- 0.46 l (bupivacaine). In contrast, FEV1 over vital capacity increased from 64.6 +/- 13.5 to 68.2 +/- 14.5% (ropivacaine) and from 62.8 +/- 12.4 to 66.5 +/- 13.6% (bupivacaine). There was no difference between ropivacaine and bupivacaine. Skin temperatures increased significantly, whereas arterial pressure and heart rate significantly decreased indicating widespread sympathetic blockade. All 20 patients tolerated surgery well. Despite sympathetic blockade, sTEA does not increase airway obstruction and evokes only a small decrease in FEV1 as a sign of mild respiratory motor blockade with no difference between ropivacaine and bupivacaine. Therefore, sTEA can be used in patients with severe chronic obstructive pulmonary disease and asthma undergoing chest wall surgery as an alternative technique to general anesthesia.