Internal thoracic impedance - a useful method for expedient detection and convenient monitoring of pleural effusion.
Measurement of internal thoracic impedance (ITI) is sensitive and accurate in detecting acute pulmonary edema even at its preclinical stage. We evaluated the suitability of the highly sensitive and noninvasive RS-207 monitor for detecting pleural effusion and for demonstrating increased ITI during its resolution. This prospective controlled study was performed in a single department of internal medicine of a university-affiliated hospital between 2012-2013. One-hundred patients aged 25–96 years were included, of whom 50 had bilateral or right pleural effusion of any etiology (study group) and 50 had no pleural effusion (controls). ITI, the main component of which is lung impedance, 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 according to well-accepted clinical and roentgenological criteria. During treatment, the ITI of the study group increased from 32.9±4.2 ohm to 42.8±3.8 ohm (p<0.0001) compared to non-significant changes in the control group (59.6±6.6 ohm, p = 0.24). Prominent changes were observed in the respiratory rate of the study group: there was a decrease from 31.2±4.0 to 19.5±2.4 ohm (35.2%) compared to no change for the controls, and a mean increase from 83.6± 5.3%-92.5±1.6% (13.2%) in O2 saturation compared to 94.2±1.7% for the controls. Determination of ITI for the detection and monitoring of treatment of patients with pleural effusion enables earlier diagnosis and more effective therapy, and can prevent hospitalization and serious complications, such as respiratory distress, and the need for mechanical ventilation.


BACKGROUND
The study is registered at ClinicalTrials.gov NCT01601444.
Department of Internal Medicine "C", Tel Aviv Sourasky Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Gideon
G
Charach
Department of Internal Medicine "C", Tel Aviv Sourasky Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Olga
O
Rubalsky
Department of Internal Medicine "C", Tel Aviv Sourasky Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Lior
L
Charach
Department of Internal Medicine "C", Tel Aviv Sourasky Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Alexander
A
Rabinovich
Department of Internal Medicine "C", Tel Aviv Sourasky Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Ori
O
Argov
Department of Internal Medicine "C", Tel Aviv Sourasky Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Ori
O
Rogowski
Department of Internal Medicine "C", Tel Aviv Sourasky Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Cardiology Department Kaplan Medical Center, affiliated to Hebrew University Medical Center, Jerusalem, Israel.
Jacob
J
George
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002307:Cardiography, Impedance / Q000295:instrumentation* / Q000379:methods; D016022:Case-Control Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000175:diagnosis* / Q000503:physiopathology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity