Prediction of Arterial Blood Gas Values from Venous Blood Gas Values in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Abstract

Arterial blood gas (ABG) analysis has an important role in the clinical assessment of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, arterial puncture or insertion of an arterial catheter has many drawbacks. The aim of this study was to evaluate whether venous blood gas (VBG) values of pH, partial pressure of carbon dioxide (PCO 2 ) and oxygen (PO 2 ), bicarbonate (HCO 3 ), and oxygen saturation (SO 2 ) can reliably predict ABG levels in patients with AECOPD. One hundred and thirty-two patients with a prior diagnosis of COPD presenting with acute exacerbation according to AECOPD criteria were included in this prospective study. AECOPD is defined as a recent increase in cough, wheezing, the volume and purulence of sputum or shortness of breath necessitating a change in regular medication, including corticosteroids or antibiotics. ABG samples were taken immediately after venous sampling, and both were analyzed. Linear regression analysis was performed and equations were established for the estimation of arterial values. The Pearson correlation coefficients for pH, PCO 2 , HCO 3 , PO 2 , and SO 2 were 0.934, 0.908, 0.927, 0.252, and 0.296, respectively. There was a significant correlation between ABG and VBG values of pH, PCO 2 , and HCO 3 ( p < 0.001). Linear regression equations for the estimation of pH, PCO 2 , and HCO 3 were as follows: arterial pH = 1.004 × venous pH; arterial PCO 2 = 0.873 × venous PCO 2 ; and arterial HCO 3 = 0.951 × venous HCO 3 . VBG analysis can reliably predict the ABG values of pH, PCO 2 and HCO 3 in patients with AECOPD. blood gas; arterial; venous; chronic obstructive pulmonary disease

Agreement between Central Venous and Arterial Blood Gas Measurements in the Intensive Care Unit

“…Nonetheless, that the patient population in the study had a predominance of patients with sepsis does limit the generalizability of our results, especially in patients with very low cardiac output. Third, the study did use central venous samples obtained from a central line, not peripheral venous samples; however, given that our study found acceptable agreement between arterial and central venous values, it would be expected that similar agreement would be found if peripheral venous samples were used, which in fact has been confirmed by both our own results and those of other studies (7)(8)(9)(10)(12)(13)(14)(15) …”

“…A number of studies have suggested that there is agreement between ABG and VBG values, although most of the previous studies were limited by specific patient group samples (e.g., patients with diabetic ketoacidosis), analysis of only one or some parameters rather than all commonly used parameters (e.g., pH, Pco 2 , and bicarbonate), or examination of only one ABG and VBG sample per patient (7)(8)(9)(10)(11)(12)(13)(14)(15). A few authors even expressed doubts about the use of VBG values in lieu of arterial values (4 -6).…”

“…Venous blood gas (VBG) analysis requires fewer punctures, is a relatively safer procedure for both the patient and the health care provider, and may be an alternative to ABG analysis for acid-base status. Although a few studies have expressed reservations regarding the accuracy of VBG values (4 -6), there is emerging evidence to suggest that there is agreement between ABG and VBG values (7)(8)(9)(10)(11)(12)(13)(14)(15). To our knowledge, no previous study has examined the agreement among all of the commonly used parameters in arterial and central VBG samples in a diverse population of medical intensive care unit (ICU) patients.…”

Can venous blood gas values be used instead of arterial blood gas values in respiratory alkalosis?

“…In clinical practice, arterial blood samples are used to evaluate many metabolic and respiratory statuses. However, arterial puncture is often painful, and local hematoma, infection, arterial injury, hemorrhage, aneurysm, embolism or thrombosis may occur [3]. On the other hand; venous blood sampling is easier, the pain is less, it can be drawn along with blood for other tests [3][4][5].…”

Blood total carbon dioxide content and bicarbonate can be used together to predict blood pH correctly in venous blood samples

“…3 It has been also reported that blood gas analyses to determine the acid-base status may be performed in venous blood samples and venous pH, bicarbonate, and base excess are in accordance with those of arterial blood samples in various patient populations. 4,5 However, the agreement of venous pCO 2 values with arterial pCO 2 values seems to be in conflict. 4,5 In this retrospective reviewing, it was aimed to yield novel formulations to predict the blood pH only from CtCO 2 and HCO 3 values which can easily be measured in venous blood samples obtained for other diagnostic and follow-up purposes.…”