Rapid Mucosal Absorption of Topical Lidocaine During Bronchoscopy in the Presence of Oral Candidiasis
Systemic absorption of lidocaine following its topical application during diagnostic procedures can produce central nervous system or cardiac toxicity. Objective signs of toxicity are more likely at plasma concentrations above 6 μml, which are only rarely reported during bronchoscopy. It is useful, therefore, to identify patient populations at risk for developing these undesired effects due to high plasma concentrations.
A 55-year-old white man weighing 65 kg was admitted with the chief complaint of increasing shortness of breath, chest pain, and an 18 kg weight loss over the prior eight months. He had an 80 pack-year smoking history. The admission chest x-ray film was suggestive of a right-sided empyema and a thoracentesis was performed. Pleural fluid was cultured and grew out Streptococcus pneumoniae, for which benzylpenicillin, 2 million units IV q 4 h was given. A chest tube was placed in the right chest for drainage. The patient was also noted to have candidiasis in the oral cavity for which topical nystatin suspension was prescribed, lo rule out the possibility of a neoplasm causing a postobstructive pneumonia, bronchoscopy was conducted. On the prior day, remarkable serum chemistry values were a slightly elevated alkaline phosphatase of 163 U/L (normal range: 50 to 145 U/L) and low serum protein, with 4.7 g/dL total protein (6.5 to 8.4 g/dL), 2.0 albumin (3.5 to 5.0 g/ dL), and 2.7 globulin (3.2 to 4.8 g/dL). Other liver function tests were normal.
Prior to and during placement of the bronchoscope, local anesthesia was achieved by the following sequential modes of administration of lidocaine: (1) 4 percent lidocaine hydrochloride solution (Xylocaine) which the patient gargled for 30 s and then expectorated at time zero (Fig 1); (2) 2 percent lidocaine hydrochloride solution delivered by atomizer to the oropharynx; (3) 2 percent lidocaine hydrochloride jelly (Xylocaine) applied by cotton swab to the posterior oropharynx and entrance to the nasal passages; and (4) 1 percent lidocaine hydrochloride solution injected through the bronchoscope after its placement through the nose. Weights or volumes of the dosage forms were measured for quantitation of the milligrams of drug actually applied. The total amount of lidocaine administered by all four modes of administration was 1,131 mg (17.4 mg/kg). in detail
Prior to premedication with atropine and codeine, written informed consent was obtained from the patient for serial phlebotomy. Blood samples were drawn through a forearm vein catheter for quantitation of lidocaine plasma concentrations using gas chromatography. While no endobronchial lesions were found on bronchoscopy, a pleural biopsy later revealed adenocarcinoma.
Figure 1. Plasma lidocaine concentrations before, during, and after bronchoscopy. Arrows mark beginning and end of the bronchoscopy procedure. Bar graphs show doses and times of administration of lidocaine solution by atomizer (hatched bar), lidocaine jelly (solid bar), and lidocaine solution through the bronchoscope (open bar).