Comparison of Pleural Pressure Measuring Instruments.

Chest

PubMedID: 24853674

Lee HJ, Yarmus L, Kidd DA, Ortiz R, Akulian J, Gilbert CR, Hughes AH, Thompson RE, Arias S, Feller-Kopman DJ. Comparison of Pleural Pressure Measuring Instruments. Chest. 2014;146(4):1007-12.
ABSTRACT PURPOSE
To compare the accuracy of a handheld digital manometer and U-tube manometer to an electronic transducer manometer during thoracentesis.

METHODS
Thirty-three consecutive patients undergoing thoracentesis were enrolled in the study. Pleural pressure (Ppl) measurements were made using a handheld digital manometer (DM, Compass, Mirador Biomedical, Seattle, WA), a U-tube water (UT) manometer and an electronic transducer (ET, reference instrument). End expiratory Ppl was recorded after catheter insertion, after each aspiration of 240 mL, and prior to catheter removal. Volume of fluid removed, symptoms during thoracentesis, pleural elastance, and pleural fluid chemistries were also evaluated.

RESULTS
594 Ppl measurements were made in thirty patients during their thoracentesis. There was a strong linear correlation coefficient between elastance for the DM and ET (r=0.9582, P<0.001). Correlation was poor between the UT and ET (r=0.0448, p=0.84). Among the 15 patients who developed cough, recorded ET pressures ranged from -9 to +9 cmH2O at the time of symptom development, with a mean (SD) = -2.93 (4.89) cmH2O. ET and DM measurements among those patients with cough had a low correlation between these measurements (R2 = 0.104, p=0.24). Nine patients developed chest discomfort and had ET pressures that ranged from -26 to +6 cmH2O, with a mean (SD) = -7.89 (9.97) cmH2O.

CONCLUSION
The handheld digital manometer provided a valid and easy to use method to measure pleural pressures during thoracentesis. Future studies are needed to investigate its utility in predicting clinically meaningful outcomes.