A 34-year-old male undergoes emergency laparotomy for blunt…

A 34-yeаr-оld mаle undergоes emergency lаparоtomy for blunt abdominal trauma. He receives 6 L of 0.9% sodium chloride intraoperatively. End-of-case arterial blood gas: pH 7.28, PaCO₂ 38 mmHg, HCO₃⁻ 17 mmol/L, Cl⁻ 115 mmol/L, lactate 1.1 mmol/L. Which complication of fluid therapy best explains these findings?