A 35-year-old client is admitted to the hospital with diabetic ketoacidosis. Results of arterial blood gases are pH 7.2, PaO2 90, PaCO2 45, and HCO3…

The client's arterial blood gas (ABG) results show a pH of 7.2, which is below the normal range of 7.35-7.45, indicating acidosis. The bicarbonate (HCO3) level is 16 mEq/L, which is also below the normal range of 22-26 mEq/L. A low pH combined with a low HCO3 is the hallmark of metabolic acidosis. This is the expected acid-base imbalance in a client with diabetic ketoacidosis (DKA) due to the overproduction of ketoacids, which consume bicarbonate. The PaCO2 of 45 mmHg is at the upper limit of normal (35-45 mmHg), indicating a lack of respiratory compensation at this time.

A. Respiratory alkalosis is characterized by a high pH (>7.45) and a low PaCO2 (<35 mmHg), which is inconsistent with the client's low pH.

B. Respiratory acidosis is characterized by a low pH (45 mmHg). The client's PaCO2 is within the normal range.

C. Metabolic alkalosis is characterized by a high pH (>7.45) and a high HCO3 (>26 mEq/L), which is the opposite of the client's findings.

1. Ignatavicius, D. D., Workman, M. L., Rebar, C. R., & Heimgartner, N. M. (2021). Medical-Surgical Nursing: Concepts for Interprofessional Collaborative Care (10th ed.). Elsevier. Chapter 14, Acid-Base Balance, pp. 223-226, Table 14.4 "Common Causes of Acid-Base Imbalances."

2. Gaspard, J. J., & Parrot, J. S. (2021). A Primer on Arterial Blood Gas Analysis. Southern Medical Journal, 114(5), 299–304. https://doi.org/10.14423/SMJ.0000000000001243 (This article details the systematic approach to ABG interpretation, confirming that a low pH with a low HCO3 indicates metabolic acidosis, Section: "Step 3: Determine the Primary Disturbance," para. 1).

3. University of Virginia School of Medicine. (n.d.). ABG Interpretation. Department of Anesthesiology. Retrieved from https://www.med.virginia.edu/anesthesiology/wp-content/uploads/sites/259/2016/01/ABG-Interpretation.pdf (This educational document outlines the steps for ABG analysis, specifying on page 2 that a pH < 7.35 and HCO3 < 22 mEq/L defines metabolic acidosis).

4. Kitabchi, A. E., Umpierrez, G. E., Miles, J. M., & Fisher, J. N. (2009). Hyperglycemic Crises in Adult Patients With Diabetes. Diabetes Care, 32(7), 1335–1343. https://doi.org/10.2337/dc09-9032 (This consensus statement from the American Diabetes Association describes the pathophysiology of DKA, noting that "the overproduction of ketoacids... leads to metabolic acidosis," Section: "Pathogenesis," para. 2).