Prophylactic nebulized lidocaine attenuates hyperdynamic response to abrupt mask inhalation of isoflurane in adults

Abstract

Study objectives To examine whether prophylactic, atomized lidocaine blunts hyperdynamic responses and catecholamine release after an abrupt increase in volatile anesthetic administration. Design Prospective, randomized, double-blind, placebo-controlled study. Setting University-affiliated hospital. Patients 22 ASA physical status I adult patients scheduled for elective surgery. Interventions Patients were randomly assigned to the saline or lidocaine group, and abruptly inhaled 5% isoflurane (4.3 MAC) after inhalation of ultrasonically nebulized lidocaine or saline via endoscopy mask. An esophageal Doppler probe was inserted via the mask to assess global hemodynamic performance. Measurements and main results Immediately after abrupt inhalation of isoflurane, heart rate (HR) in the saline group increased significantly and mean arterial pressure (MAP) remained unchanged, whereas HR in the lidocaine group remained unchanged, and MAP decreased significantly. No significant differences were noted between the saline and lidocaine groups in aortic blood flow, stroke volume in the aorta, total systemic vascular resistance in the aortic circuit, or aortic diameter. The plasma norepinephrine concentration increased in both groups after isoflurane inhalation, significantly so in the saline group but not in the lidocaine group. Conclusion Prophylactic ultrasonically nebulized lidocaine (2 mg/kg) obtunds the hyperdynamic responses to abrupt inhalation of 5% isoflurane but does not completely block catecholamine release.