The Impact of Thoracentesis On Postprocedure Pulse Oximetry.

Abstract

Although thoracentesis can offer considerable symptomatic relief to the patient, its physiologic impact on oxygen saturation has not been well established in the literature. This study aimed to evaluate the impact of thoracentesis on postprocedure pulse oximetry (SpO2) in an inpatient population. A retrospective study of patients undergoing thoracentesis from January 2012 to November 2017 was performed. Inclusion criteria were age above 18 and thoracentesis performed in an inpatient setting. Records were reviewed for patient demographics, procedure reports, and laboratory values. SpO2 and FiO2 values were collected before and 6 and 24 hours postprocedure. Multivariable linear regression models were used to evaluate for changes in SpO2 and SpO2/FiO2. Analyses were adjusted for age, sex, serum hemoglobin, effusion etiology, volume removed, nonexpandable lung physiology and procedural complications and FiO2. A total of 502 patients were included. The mean (SD) age was 60 (14) years, and 53.4% of the patients were male. The most common cause of pleural effusion was malignant effusion (37%). The median (interquartile range) volume of fluid removed was 1400 (1000 to 2000) mL and nonexpandable lung physiology was noted in 35%. There was no significant within-subject difference in 24 hours postprocedure SpO2 compared with preprocedure SpO2. In multivariable analysis, there was a small increase in 24-hour postprocedure SpO2 [β=0.31, 95% confidence interval (0.22, 0.41), P<0.01] and a similar small increase in 24-hour postprocedure SpO2/FiO2 [β=0.84, 95% confidence interval: (0.68, 1.01), P<0.01). Among inpatients undergoing thoracentesis, there is no clinically significant change in SpO2 or SpO2/FiO2 at 24-hours post-procedure compared to pre-procedural SpO2 or SpO2/FiO2.