Arterial Blood Gas Results Rarely Influence Emergency Physician Management of Patients with Suspected Diabetic Ketoacidosis

Abstract

Objectives: To test the hypothesis that arterial blood gas (ABG) results for patients with suspected diabetic ketoacidosis (DKA) do not influence emergency physicians' management decisions and to assess correlation and precision between venous pH and arterial pH. Methods: Prospective, observational study of emergency physicians' decision making for consecutive ED patients with suspected DKA. Inclusion criteria were capillary blood glucose equal to or greater than 200 mg/dL, ketonuria, and clinical signs and symptoms of DKA. Venous pH, chemistry panel, and ABGs were drawn before treatment. Attending emergency physicians indicated planned management and disposition on a standardized form before and after reviewing ABG and venous pH results. This study was powered to detect a 10% difference in management decisions (n ¼ 195). Pearson's correlation and Bland-Altman bias plot were used to compare venous pH and arterial pH. Results: ABG analysis changed the emergency physicians' diagnosis in 2/200 cases (1.0%; 95% confidence interval [95% CI] ¼ 0.3% to 3.6%), altered treatment in 7/200 cases (3.5%; 95% CI ¼ 1.7% to 7.1%), and changed disposition in 2/200 cases (1.0%; 95% CI ¼ 0.3% to 3.6%). The pH value of the ABGs changed the treatment or disposition in 5/200 patients (2.5%; 95% CI ¼ 1.1% to 5.7%). The Po 2 and Pco 2 results of the ABGs altered treatment and disposition in 2/200 patients (1.0%; 95% CI ¼ 0.3% to 3.6%). Venous pH correlated well with arterial pH (r ¼ 0.951), and bias plotting yielded a bias value of ÿ0.015 (6 0.006 pH units). Conclusions: ABG results rarely influenced emergency physicians' decisions on diagnosis, treatment, or disposition in suspected DKA patients. Venous pH correlated well and was precise enough with arterial pH to serve as a substitute.

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.…”

Joint British Diabetes Societies guideline for the management of diabetic ketoacidosis

“…This difference will not influence either diagnosis or management of diabetic ketoacidosis and it is not necessary to use arterial blood to measure acid base status [29]. Venous blood can be used in portable and fixed blood gas analysers and therefore venous measurements (bicarbonate, pH and potassium) are easily obtained in most admitting units.…”

Diabetic Ketoacidosis: Why Measure the Blood Gas at All?

“…To the Editor:-The recent study 1 by Ma et al is laudable in its attempt to demonstrate that routine arterial blood gas measurement in patients with ''suspected diabetic ketoacidosis (DKA)'' is unnecessary. However, insofar as it focuses on the venous blood gas as a surrogate, perhaps it does not go far enough.…”