Is fibreoptic bronchoscopy in patients with lung cancer and hepatic metastases potentially dangerous?

Plasma lignocaine levels were measured in 18 patients with lung cancer undergoing fibreoptic bronchoscopy to determine whether those with hepatic metastases and disturbed hepatic function were at special risk from lignocaine toxicity. Peak plasma lignocaine levels were in fact lower in six patients with hepatic metastases and deranged hepatic function tests than in the nine patients with no evidence of hepatic metastases or dysfunction (mean +/- SEM 1.89 +/- 0.2 mg/litre and 2.60 +/- 0.3 mg/litre respectively, P not significant). The peak plasma lignocaine level did not correlate with tests of liver function but did correlate with age. Using a total dose of lignocaine of less than 400 mg, plasma lignocaine levels remained below the toxic range in all patients. The peak plasma lignocaine level correlated significantly with the amount of drug administered directly into the bronchial tree (P less than 0.05) rather than total dose administered. Patients with hepatic metastases from lung cancer do not appear to be at an increased risk from the toxic effects of lignocaine topical anaesthesia if moderate doses are used.