title: Establishing a gradient between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide in patients with acute respiratory distress syndrome.
abstract: End-tidal carbon dioxide (ETCO2) monitoring is useful in many situations. However, ETCO2monitoring is unreliable in patients with acute respiratory distress syndrome (ARDS) due to widespread lung inflammation. In our study, we attempt to establish the gradient between the arterial pressure of carbon dioxide (PaCO2) and ETCO2in patients with ARDS, which we defined as the PaETCO2gradient. The main objective of the study was to establish a PaETCO2gradient in each severity of ARDS. We analyzed 35 patients with ARDS and a total of 88 arterial blood gases were included. PaCO2, PaO2/FiO2and ETCO2were measured. Patients were stratified into mild, moderate and severe ARDS as classified by the Berlin ARDS criteria. PaCO2and ETCO2were compared at each severity stratification. The mean PaCO2was 50.0, the mean ETCO2was 26.6 and the gradient among all samples was 23.24 (±12.02). The mean gradient for each severity is as follows: mild: 19.3 (±9.9), moderate: 27.9 (±13.2) and severe: 23.9 (±7.8). The difference between the PaETCO2gradient of the mild to moderate (p=0.001) and mild to severe groups (p=0.01) reached statistical significance. However, the difference between the moderate to severe groups did not reach statistical significance (p=0.48). We found the gradient between PaCO2and ETCO2in patients with ARDS is vast and tends to worsen with increasing severity of ARDS. This indicates that the gradient between the 2 may be used as an indicator of increasing severity of ARDS.
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Tariq
authors.initials: T
authors.lastname: Yousuf
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Taylor
authors.initials: T
authors.lastname: Brinton
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Ghulam
authors.initials: G
authors.lastname: Murtaza
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wozniczka
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Khansa
authors.initials: K
authors.lastname: Ahmad
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Joy
authors.initials: J
authors.lastname: Iskandar
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Raju
authors.initials: R
authors.lastname: Mehta
authors.affiliation: Department of Cardiology, Illinois Masonic Medical Center, Chicago, Illinois, USA.
authors.forename: Hesam
authors.initials: H
authors.lastname: Keshmiri
authors.affiliation: Department of Medicine, Advocate Christ Medical Center, Oak Lawn, Illinois, USA.
authors.forename: Tabassum
authors.initials: T
authors.lastname: Hanif
mesh_terms: D001158:Arteries / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010313:Partial Pressure; D012128:Respiratory Distress Syndrome / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide
keywords: Intensive Care Units; Respiratory Distress Syndrome, Adult