The effects of thoracic epidural analgesia with bupivacaine 0.25% on ventilatory mechanics in patients with severe chronic obstructive pulmonary disease

Optimal analgesia is important after thoracotomy in pulmonary-limited patie nts to avoid pain-related pulmonary complications. Thoracic epidural anesth esia (TEA) can provide excellent pain relief. However, potential paralysis of respiratory muscles and changes in bronchial tone might be unfavorable i n patients with end-stage chronic obstructive pulmonary disease (COPD). The refore, we Evaluated the effect of TEA on maximal inspiratory pressure, pat tern of breathing, ventilatory mechanics, and gas exchange in 12 endstage C OPD patients. Pulmonary resistance, work of breathing, dynamic intrinsic po sitive end-expiratory pressure, and peak inspiratory and expiratory flow ra tes were evaluated by assessing esophageal pressure and airflow. An increas e in minute ventilation (7.50 +/- 2.60 vs 8.70 +/- 2.10 L/min; P = 0.04) by means of increased tidal volume (0.46 +/- 0.16 vs 0.53 +/- 0.14 L/breath; P = 0.003) was detected after TEA. These changes were accompanied by an inc rease in peak inspiratory flow rate (0.48 +/- 0.17 vs 0.55 +/- 0.14 L/s; P = 0.02) and a decrease in pulmonary resistance (20.7 +/- 9.9 vs 16.6 +/- 8. 1 cm H2O.L-1.s(-1) P = 0.02). Peak expiratory flow rate, dynamic intrinsic positive end-expiratory pressure, work of breathing, Pao(2), and maximal in spiratory pressure were unchanged (all P > 0.50). We conclude that TEA with bupivacaine 0.25% can be used safely in end-stage COPD patients.