CHLORIDE CONCENTRATION, NOT SODIUM AND POTASSIUM, IS SELECTIVELY HIGHER IN HEART FAILURE-ASSOCIATED PLEURAL EFFUSION

Abstract

SESSION TITLE: Pleural Disease SESSION TYPE: Original Investigations PRESENTED ON: 10/07/2018 02:15 pm - 03:15 pm PURPOSE: My recent studies have shown that serum chloride is a key electrolyte for the regulation of the fluid distribution or shift between the intravascular and cellular (red blood cell) spaces in the heart failure (HF) pathophysiology. Electrolyte chloride may have an important role for accumulation of pleural fluid in acutely worsening HF. The present study evaluated the hypothesis that a differential chloride concentration exists between the pleural fluid and blood serum in patients with worsening HF. METHODS: Seventeen consecutive patients that presented to Nishida hospital with pleural effusion and underwent thoracentesis during the study period from May 2017 to December 2017 were retrospectively analyzed. Worsening HF was diagnosed based on clinical criteria (presentation, echocardiography, serum b-type natriuretic peptide, and response to therapy). Biochemical measurements were performed on samples of non-heparinized pleural fluid and peripheral venous blood obtained within 2 h from each other. Pleural effusion was classified as transudates or exudates according to the classic Light’s criteria. Namely, the effusion was classified as exudates when any of the following criteria were met: 1) pleural to serum protein ratio >0.5, 2) pleural fluid LDH >200 IU, and 3) pleural fluid-to-serum LDH ratio >0.6. The effusion-serum electrolyte gradient was determined as [(pleural fluid electrolyte) minus (serum electrolyte)]. Statistical analysis was performed by one-way analysis of variance with Tukey’s post-hoc test. RESULTS: Fifteen patients (53% men; 85±11 years) were diagnosed with HF-associated pleural effusion; based on the Light’s criteria, 10 of these patients were classified as having transudative effusion and the other 5 patients were classified as having exudative effusion [fulfilling only one (n=4) or both (n=1) of the LDH criteria]. The effusion-serum electrolyte gradient was significantly higher in chloride (7.4 ± 2.6 mEq/L; range 4 – 14 mEq/L) than in sodium (0.87 ± 1.36 mEq/L; range -1 – 4 mEq/L) and potassium (-0.12 ± 0.254 mEq/L; range -0.8 – 0.2 mEq/L; P < 0.001 for each). CONCLUSIONS: In acutely worsening HF patients with associated pleural effusion, concentration of chloride in the pleural effusion is greater than that in the serum, indicating that chloride may have an important and active role in the formation and retention of body fluid in the pleural space, and possibly in the interstitial space. CLINICAL IMPLICATIONS: The finding of higher chloride concentration in HF-associated pleural fluid as shown in this study should raise innovative idea for investigating the pleural fluid pathophysiology. According to the “revised Starling equation and the glycocalyx model”, anionic electrolyte chloride may penetrate the endothelial glycocalyx layer, diffuse into the pleural space, and hold pleural fluid by its tonicity under condition of insufficient drainage via venous and/or lymphatic channels. DISCLOSURES: No relevant relationships by Hajime Kataoka, source=Web Response