Validation of a Rapid Bronchoalveolar Lavage Fluid Colorimetric Evaluation for Assessing the Severity of Exercise-Induced Pulmonary Hemorrhage in Horses in Field Conditions.

Diagnosis and assessment of severity of exercise-induced pulmonary hemorrhage (EIPH) relies on postexercise visualization of fresh blood in the airways via tracheobronchoscopic examination (TBE) and/or counting erythrocytes in bronchoalveolar lavage fluid (BALFRBC). Determining the BALFRBC is more sensitive than TBE but its usefulness is hampered by the need to have BALFRBC counted at a laboratory. We explored the feasibility of evaluating the severity of EIPH by using a color chart comprised of five shades of red and matching those colors with the color of BALF immediately following collection. To validate the technique, sets of ten BALF samples with known BALFRBC numbers were created and randomly shown to two groups of 18 observers who independently matched the color of the BALF with one of the shades of red displayed on the screen of a smartphone. Interobserver and intra-observer agreements regarding colors were > 0.9. The utility of the color chart was further validated under field conditions at two barrel racing events where 63 BALF samples were collected from 21 horses and BALF color was graded independently by three observers. The number of BALFRBC in the 63 samples ranged from 25-1,100,000/µL. EIPH was diagnosed in 39 samples based on the detection of color, and all 5 colors were matched multiple times with BALF samples. Overall, the color of the BALF was related to the number of BALFRBC. Colorimetric evaluation of BALF represents a practical and reliable option for rapid postexercise assessment of the presence and severity of EIPH.

Effects of exercise, furosemide, blood depletion, and reinfusion on body fluid compartment volumes in horses.

High pulmonary blood pressure contributes to exercise-induced pulmonary hemorrhage. The objective of this study was to use bioimpedance spectroscopy to assess body fluid compartment volumes under 3 conditions in 6 racehorses: i) Pre- and post-supramaximal treadmill exercise (control); ii) Exercise 4 hours after furosemide (0.5 mg/kg body weight, IV); iii) Exercise, removal of ~14 L of blood and subsequent reinfusion of the blood. Statistical analysis used linear mixed effects models. Body compartment volumes did not change during the control runs. Total body water (TBW) (P = 0.007, P = 0.007), extracellular fluid (ECF) (P = 0.003, P = 0.003), and intracellular fluid (ICF) volumes (P = 0.04, P = 0.04) decreased pre- and post-exercise following furosemide administration. The ICF trended to decrease (P = 0.07) after slow removal of blood. Blood reinfusion increased TBW (P = 0.02, P = 0.02) and ICF (P = 0.005, P = 0.005) pre- and post-exercise.

Effets de l'exercice, du furosémide, de la diminution sanguine et de la ré-infusion sur les volumes des liquides corporels compartimentés chez les chevaux. Une pression sanguine pulmonaire élevée contribue à des hémorragies pulmonaires induites par l'exercice. L'objectif de la présente étude était d'utiliser la spectroscopie à bio-impédance pour évaluer les volumes des liquides corporels compartimentés sous trois conditions chez six chevaux de course : i) Pré- et post-supramaximal exercice au tapis roulant (témoin); ii) Exercice 4 h après administration de furosémide (0,5 mg/kg de poids corporel, IV); iii) Exercice, retrait d'environ 14 L de sang et ré-infusion subséquente du sang. Les analyses statistiques utilisaient des modèles linéaires à effets mixtes. Les volumes des compartiments corporels n'ont pas changé durant les essais témoins. Les volumes de la quantité totale d'eau corporelle (TBW) (P = 0,007, P = 0,007), de liquide extracellulaire (ECF) (P = 0,003, P = 0,003) et liquide intracellulaire (ICF) (P = 0,04, P = 0,04) ont diminué pré- et post-exercice à la suite de l'administration de furosémide. L'ICF avait tendance à diminuer (P = 0,07) à la suite du lent retrait de sang. La ré-infusion de sang augmenta la TBW (P = 0,02, P = 0,02) et l'ICF (P = 0,005, P = 0,005) pré- et post-exercice.(Traduit par Dr Serge Messier).