Anatomical distribution of bronchoalveolar lavage fluid as assessed by digital subtraction radiography.

Abstract

A digital subtraction imaging technique was used to visualise directly the anatomical distribution of 3 x 60 ml aliquots of saline containing a low concentration of radio-opaque dye, introduced sequentially into a segment of the middle lobe. It was possible to estimate the relative movement of fluid within the segment during the sequential aspiration of each of these aliquots. The first 60 ml aliquot introduced stayed close to the bronchoscope and probably sampled only the proximal airways. With the introduction of cumulative volumes of 120 ml or more, the fluid filled the segment more evenly. Aspiration then moved fluid back from the periphery, implying that the aspirate had also lavaged both distal airways and alveoli.Bronchoalveolar lavage has become increasingly popular as a diagnostic and research tool over the last 15 years. Its applications have been as diverse as the measurement of mediators after antigen challenge in asthmatic patients' and the diagnosis of Pneumocystis carinii infection in immunosuppressed patients,2 although it is most widely used in the assessment and diagnosis of interstitial lung disease.3 The anatomical distribution of fluid introduced during bronchoalveolar lavage, however, has never been thoroughly investigated and there is wide variation in the way the procedure is performed. The volume instilled by different operators has ranged from 204 to 3005 ml and the site of lavage has varied from first order bronchi6 to subsegmental bronchi.7 In this study we have attempted to define the fluid distribution occurring during a standard bronchoalveolar lavage protocol, as routinely used in our practice, and to assess the movement of fluid that occurs at aspiration. muscularly 30 minutes before bronchoscopy, and 10 mg of diazepam was injected intravenously immediately before the start of the procedure. Over 15 minutes 4ml of 2% lignocaine were administered by nebuliser (Porta-Neb, Medic-aid) and I ml was injected into the trachea via the cricoid membrane, which allowed the procedures to be completed with no more than 2 ml of additional local anaesthetic. Peroral bronchoscopy was then performed with the subject supine and the instrument was wedged into a segment of the middle lobe. The medial segment was chosen for lavage in the first subject (study 1) and the lateral segment in the second (study 2). Both studies were recorded with a computer linked digital radiography system (Picker DAS 21 1), which exposed each subject to a total of 15 chest radiographs. A baseline image of the right hemithorax was taken in the anteroposterior plane at functional residual capacity (FRC) at the beginning of each study for subtraction from subsequent images. This allowed better low contrast sensitivity. Three successive aliquots of sterile phosphate buffered saline containing a 5% solution of the radioopaque iodinated dye lopamidol (Merck) were introduced at 25°C. This dye concentration was selected as a result of a preliminary series of experiments in which test tubes containing 1%, 5%, and 10% iop...

Comparison of99mTc‐DTPA and urea for measuring cefepime concentrations in epithelial lining fluid

“…Shortening the lavage fluid dwell time decreases the error in the estimation of ELF dilution by BAL fluid, by reducing urea exchange during lavage. However, it has been shown that the first aliquot of instilled fluid samples only the proximal airways, and that the peripheral airspaces of a lung segment are filled more evenly as lavage cycles are repeated [23]. In light of this fact, BALDWIN et al [24] have proposed a "microlavage" technique using a standard bronchial brush tube for rapid lavage of a peripheral lung subsegment.…”

Intrapulmonary Distribution and Pharmacokinetics of Laninamivir, a Neuraminidase Inhibitor, after a Single Inhaled Administration of Its Prodrug, Laninamivir Octanoate, in Healthy Volunteers

“…It has been reported that the first aliquot of BAL fluid is more related to bronchi and that the others are more related to the more distal parts of the lung, including bronchioles and alveoli (7,12). In this study, the distribution of LO and laninamivir in the lung was explored by comparison of the concentrations in the first BAL fluid and those in the remaining aliquots recovered, as performed in a study of zanamivir (19).…”

“…The distribution of zanamivir after multiple oral inhaled administrations was also evaluated by analyzing the concentration of zanamivir in both the first BAL fluid and subsequent BAL fluid aliquots, since the contents of BAL fluid may vary according to the segment of the washed lung. The first aliquot of BAL fluid is considered to be more related to bronchi, and subsequent aliquots are considered to be more related to the more distal parts of the lung, including bronchioles and alveoli (7,12). Given that LO is administered as a dry powder formulation containing various particle sizes of LO, inhaled LO particles do not necessarily distribute evenly in the respiratory tract.…”

Analysis of vancomycin entry into pulmonary lining fluid by bronchoalveolar lavage in critically ill patients

“…In studies that use BAL for assessment of critically ill patients, amounts of BAL fluid have ranged from 100 to 300 ml (21). At least 100 to 120 ml is probably necessary for retrieving secretions from the periphery of the lung subsegment that is lavaged, as assessed by digital subtraction radiography and studies with sequential lavage (12,21).…”