# A client with diabetic ketoacidosis has pH 7.28, PaCO2 26 mm Hg, and HCO3 12 mEq/L. Using Winter's formula, complete the acid-base interpretation. > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=393370&lang=en > language: en > subject: Laboratory Values > category: ROR ## Question A client with diabetic ketoacidosis has pH 7.28, PaCO2 26 mm Hg, and HCO3 12 mEq/L. Using Winter's formula, complete the acid-base interpretation. The primary disorder is ::선택::respiratory alkalosismetabolic acidosismetabolic alkalosisrespiratory acidosis. Winter's formula predicts a PaCO2 of ::선택::10 to 14 mm Hg24 to 28 mm Hg35 to 45 mm Hg48 to 52 mm Hg. The measured PaCO2 indicates ::선택::an additional primary respiratory acidosisappropriate respiratory compensation without a second primary respiratory disorderan additional primary respiratory alkalosisabsence of metabolic acidemia. ## Explanation The low pH and low bicarbonate identify primary metabolic acidosis. Winter's formula gives an expected PaCO2 of 24 to 28 mm Hg: (1.5 × 12) + 8 ± 2. The measured PaCO2 of 26 mm Hg is within that range, so respiratory compensation is appropriate and there is no evidence from these values of an additional primary respiratory disorder. Appropriate compensation does not need to normalize the pH. ## In-depth explanation Correct Answer The primary disorder is metabolic acidosis, expected PaCO2 is 24 to 28 mm Hg, and the measured value indicates appropriate respiratory compensation without a second primary respiratory disorder. Why It Fits The bicarbonate decrease explains the acidemia, and the measured PaCO2 falls inside the calculated compensatory range. Clinical Picture Deep rapid breathing lowers carbon dioxide in response to metabolic acid. Winter's formula distinguishes expected compensation from an additional respiratory problem. Memory Link Low pH plus low HCO3 means metabolic acidosis; calculate the expected PaCO2 instead of guessing compensation. NCLEX Rule A PaCO2 above the expected range suggests added respiratory acidosis; below the range suggests added respiratory alkalosis. Why the Alternatives Fail Calling this respiratory alkalosis ignores the primary bicarbonate decrease. Calling compensation inadequate only because pH remains low ignores the calculated expected range. Sources 12024 Hyperglycemic Crises Consensus Report 2Merck Manual: Acid-Base Disorders 32026 NCLEX-RN Test Plan ## Clinical scenario The client is awake with deep, rapid respirations. Expected PaCO2 = (1.5 × HCO3) + 8 ± 2. The nurse must identify the primary disorder and decide whether the measured PaCO2 suggests a second respiratory disorder. ## Key concepts - **Winter's formula** — A calculation used in metabolic acidosis to estimate expected PaCO2: (1.5 × HCO3) + 8 ± 2 mm Hg. - **Metabolic acidosis** — An acid-base disorder in which a primary decrease in bicarbonate lowers blood pH. - **Mixed acid-base disorder** — More than one primary acid-base process, suggested when compensation falls outside the expected range. ## Related questions - [A 56-year-old patient presents to the ED with BP 226/132, severe occipital headache, blurr…](https://mymerci.kr/pages/nclex_q.php?qn_id=372715&lang=en) - [The emergency nurse reviews six presentations involving glucose dysregulation. Identify th…](https://mymerci.kr/pages/nclex_q.php?qn_id=393404&lang=en) - [A severely malnourished client begins tube feeding. Twenty-four hours later, phosphorus fa…](https://mymerci.kr/pages/nclex_q.php?qn_id=396144&lang=en) - [The nurse receives laboratory results for four clients. Which result requires immediate fo…](https://mymerci.kr/pages/nclex_q.php?qn_id=497619&lang=en) - [The client has received a heparin infusion for 5 days. Click the laboratory result that re…](https://mymerci.kr/pages/nclex_q.php?qn_id=499743&lang=en) - [An adult with DKA is being treated with IV fluids, insulin drip, and electrolyte replaceme…](https://mymerci.kr/pages/nclex_q.php?qn_id=568336&lang=en) - [A 73-year-old client with type 2 diabetes is admitted from a long-term care facility after…](https://mymerci.kr/pages/nclex_q.php?qn_id=617281&lang=en) - [A client on postoperative day 6 after hip replacement has received subcutaneous unfraction…](https://mymerci.kr/pages/nclex_q.php?qn_id=617366&lang=en) ## Read in another language - [en](https://mymerci.kr/pages/nclex_q.php?qn_id=393370&lang=en) - [ko](https://mymerci.kr/pages/nclex_q.php?qn_id=393370&lang=ko) - [ja](https://mymerci.kr/pages/nclex_q.php?qn_id=393370&lang=ja) - [zh-TW](https://mymerci.kr/pages/nclex_q.php?qn_id=393370&lang=zh-tw) - [vi](https://mymerci.kr/pages/nclex_q.php?qn_id=393370&lang=vi) --- More free questions: [NCLEX-RN Practice](https://mymerci.kr/pages/nclex_bank.php?lang=en) _For study reference only. Always follow current clinical guidelines and your institution’s protocols._