The Usefulness of Monitoring Pleural Effusion Treatment by the Internal Thoracic Impedance Method

Background: Internal thoracic impedance (ITI) is a sensitive and reliable method used to detect pulmonary fluids accumulation as, pulmonary edema or pleural effusion. The current study deals with this noninvasive method in heart failure patients, its usefulness in detecting pleural effusion before the appearance of clinical symptoms and for demonstrating increased ITI during its resolution. Methods: A prospective controlled study performed in a single department of internal medicine belonging to a university-affiliated hospital between the years - 2012-2013. Sixty two patients (ages ranging from 41 to 94) were recruited for the study, of whom 31 with bilateral or right pleural effusion of any etiology (study group) and 31without pleural effusion (control group) who were admitted because of heart failure (HF). ITI was continuously measured by the RS-207 monitor. The predictive value of ITI monitoring was determined by 8 measurements taken every 8 hours. Pleural effusion was diagnosed and followed by main clinical signs and also chest X ray as a gold standard modality before and at the end of the monitoring. Results: During the 56 hours of treatment, the median ITI of the study group increased by 21.5% -from 33.1±4.2 to 42.1±3.9 ohm (P < 0.001) as compared to the non significant changes in the control group 59.4±5.2 (P = NS). Prominent changes were observed in the respiratory rate (RR) of the study group: there was a decrease from 31.2±4.2to 19.7±2.3 (36.5%) - as compared to no changes for the controls, and a mean increase of elevation from 83.5±5.3% (9.1%) in O2 saturation to 92.4±1.5% as compared to94.3±2.1 (p-NS) for the controls. Conclusion: ITI methodology is useful for the diagnosis and monitoring of treatment of HF patients with pleural effusion as it enables diagnosis in the preclinical stage. ITI may provide early and better treatment, and can prevent complications such as respiratory distress, intubation and make hospitalization unnecessary. There were no significant ITI changes in HF patients as compared to the mixed general population.