Thoracoscopic Findings and Pharmacokinetics of Inhaled Fluorescein in a Pig Model

Abstract

Background: Fluorescein-enhanced autofluorescence thoracoscopy (FEAT) reveals regions of abnormal fluorescence in patients with primary spontaneous pneumothorax and in normal subjects. Some of these lesions are undetectable by white light thoracoscopy and it has been hypothesized that they represent underlying pleural and/or parenchymal abnormalities. Objectives: In order to standardize and evaluate this novel technique, we developed an animal model. Methods: Six pigs underwent thoracoscopy after the inhalation of nebulized sodium fluorescein by either volume-controlled mechanical ventilation or spontaneous ventilation. Pleural cavity and lung surface were inspected by white light thoracoscopy and FEAT during a period of 90 min. Fluorescence intensities were quantified in pleura and in blood. Regions of interest were examined postmortem for a histological assessment of the lesions. Results:FEAT lesions were observed in all animals, with a maximum intensity of the lesions 20–30 min after the onset of fluorescein administration. The plasma concentrations of sodium fluorescein reached a maximum after approximately 20 min. The microscopic findings suggest that fluorescein accumulates in the subpleural space of better ventilated lung areas. Conclusions:This is the first animal model using FEAT. Valuable information has been gathered but further investigations are required to explain the phenomena observed in humans and pigs.

New Challenges in Medical Thoracoscopy

“…Thoracoscopy has been used after inhalation of fluorescein to study its distribution in animals [16] and to detect bullae in patients with PSP (fig. 1).…”

Value of Autofluorescence in Video-Assisted Thoracoscopic Surgery in Pleural Diseases

“…Of these, 169 biopsies were from pleural thickenings (118 lesions) and 95 were from nodules (78 lesions). The mean number of biopsies per patient was 8 (range, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], and the mean numbers of nodules and pleural thickenings biopsied per patient were 6.7 and 6.5, respectively.…”

“…In contrast to bronchoscopy, AF is not widely used in videothoracoscopy at present and the English literature contains only a few articles that discuss this application. [2][3][4][15][16][17][18][19] Our aim in this study was to determine whether AF systems contribute additional information to WL examination when attempting to detect malignant lesions in pleural pathologies during video-assisted thoracic surgery (VATS). We liked to know whether the effectiveness of WL and AF-mode combination would be different for different pathologies or different lesions, in case it has an additional effect to find malignancies of the pleura.…”

Autofluorescence thoracoscopy in pleural disease: does it have clinical relevance?

“…Fluoresceinenhanced thoracoscopy was performed in a pig model [5]. Again, regions of enhanced subpleural fluorescence were noticed.…”