PULMONARY SYMPATHETIC DENERVATION DOES NOT INCREASE AIRWAY-RESISTANCEIN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE (COPD)

Whether or not neural blockade of pulmonary sympathetic innervation is of relevance for airway resistance in patients with chronic obstructi ve pulmonary disease (COPD) is unknown. Accordingly we evaluated airwa y resistance during sympathetic blockade by high thoracic epidural ana esthesia in patients with COPD. Before and 45 min after thoracic epidu ral injection of bupivacaine 0.75% (6-8 ml; n=10) total respiratory re sistance (oscillometry, R(OS)), vital capacity (VC), forced expiratory vital capacity in 1 s (FEV(1), [% VC]), functional residual capacity (FRC; helium dilution method), and arterial blood gases were measured. Three additional patients received bupivacaine intravenously (1.2 mg . min(-1) for 45 min), another three received saline epidurally. Senso ry blockade covered segment Cg through Tg AS an indicator of widesprea d sympathetic blockade including the lungs, skin temperature increased significantly on thumb and little toe. Despite pulmonary sympathetic denervation R(OS), FEV(1), and FRC remained unchanged, while VC decrea sed slightly, probably due to intercostal muscle blockade. Blood gases remained constant. Neither intravenous bupivacaine nor epidural salin e evoked directional changes. Since, in contrast to beta-adrenoceptor blockade, pulmonary sympathetic denervation did not increase airway re sistance in patients with COPD, neural sympathetic blockade seems to b e of no relevance for airway resistance in these patients.