Correlation of Venous Blood Gas and Pulse Oximetry With Arterial Blood Gas in the Undifferentiated Critically Ill Patient.
BACKGROUND
Blood gas analysis is often used to assess acid-base, ventilation, and oxygenation status in critically ill patients. Although arterial blood gas (ABG) analysis remains the gold standard, venous blood gas (VBG) analysis has been shown to correlate with ABG analysis and has been proposed as a safer less invasive alternative to ABG analysis.


OBJECTIVE
The purpose of this study was to evaluate the correlation of VBG analysis plus pulse oximetry (SpO2) with ABG analysis.


METHODS
We performed a prospective cohort study of patients in the emergency department (ED) and intensive care unit (ICU) at a single academic tertiary referral center. Patients were eligible for enrollment if the treating physician ordered an ABG. Statistical analysis of VBG, SpO2, and ABG data was done using paired t test, Pearson χ2, and Pearson correlation.


RESULTS
There were 156 patients enrolled, and 129 patients completed the study. Of the patients completing the study, 53 (41.1%) were in the ED, 41 (31.8%) were in the medical ICU, and 35 (27.1%) were in the surgical ICU. The mean difference for pH between VBG and ABG was 0.03 (95% confidence interval: 0.03-0.04) with a Pearson correlation of 0.94. The mean difference for pCO2between VBG and ABG was 4.8 mm Hg (95% confidence interval: 3.7-6.0 mm Hg) with a Pearson correlation of 0.93. The SpO2correlated well with PaO2(the partial pressure of oxygen in arterial blood) as predicted by the standard oxygen-hemoglobin dissociation curve.


CONCLUSIONS
In this population of undifferentiated critically ill patients, pH and pCO2on VBG analysis correlated with pH and pCO2on ABG analysis. The SpO2correlated well with pO2on ABG analysis. The combination of VBG analysis plus SpO2provided accurate information on acid-base, ventilation, and oxygenation status for undifferentiated critically ill patients in the ED and ICU.
1 Department of Emergency Medicine, Christiana Care Health System, Newark, DE, USA.
Eli
E
Zeserson
1 Department of Emergency Medicine, Christiana Care Health System, Newark, DE, USA.
Ben
B
Goodgame
1 Department of Emergency Medicine, Christiana Care Health System, Newark, DE, USA.
J Daniel
JD
Hess
1 Department of Emergency Medicine, Christiana Care Health System, Newark, DE, USA.
Kristine
K
Schultz
1 Department of Emergency Medicine, Christiana Care Health System, Newark, DE, USA.
Cynthia
C
Hoon
2 Department of Respiratory Care, Unity Point Health, Des Moines, IA, USA.
Keith
K
Lamb
3 Department of Medicine, Christiana Care Health System, Newark, DE, USA.
Vinay
V
Maheshwari
4 Department of Surgery, Capital Health, Trenton, NJ, USA.
Steven
S
Johnson
5 Department of Behavioral Health and Nutrition, University of Delaware, Newark, DE, USA.
Mia
M
Papas
1 Department of Emergency Medicine, Christiana Care Health System, Newark, DE, USA.
James
J
Reed
6 Department of Emergency Medicine, Denver Health Medical Center, Denver, CO, USA.
Michael
M
Breyer
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis / Q000379:methods; D003422:Critical Care / Q000379:methods*; D016638:Critical Illness; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies; D055815:Young Adult
D010100:Oxygen
blood gas analysis; critical care; oximetry