Comparison of results for weight-adjusted and fixed-amount bronchoalveolar lavage techniques in healthy Beagles

Abstract

To compare recovery of epithelial lining fluid (ELF) in bronchoalveolar lavage fluid (BALF) by use of weight-adjusted or fixed-amount volumes of lavage fluid in dogs. 13 healthy Beagles. Dogs were allocated to 2 groups. In 1 group, the right caudal lung lobe was lavaged on the basis of each dog's weight (2 mL/kg, divided into 2 aliquots) and the left caudal lung lobe was lavaged with a fixed amount of fluid (50 mL/dog, divided into 2 aliquots). In the second group, the right and left caudal lung lobes were lavaged by use of the fixed-amount and weight-adjusted techniques, respectively. The BALF was collected by use of bronchoscopy. A recovery percentage ≥ 40% was required. The proportion of ELF was calculated by use of the following equation: (concentration of urea in BALF/concentration of urea in serum) × 100. Mean ± SD proportion of ELF in BALF was 2.28 ± 0.39% for the weight-adjusted technique and 2.89 ± 0.89% for the fixed-amount technique. The SDs between these 2 techniques differed significantly (calculated by comparing 2 covariance structures [unstructured and compound symmetry] in a repeated-measures mixed ANOVA). The findings strongly suggested that use of a weight-adjusted bronchoalveolar lavage technique provided a more uniform ELF recovery, compared with that for a fixed-amount bronchoalveolar lavage technique, when urea was used as a marker of dilution. A constant ELF fraction can facilitate more accurate comparisons of cellular and noncellular constituents in BALF among patients of various sizes.