Delayed Onset Hypercapnia in Patients With Anemia Undergoing Total Laparoscopic Hysterectomy: A Report of 2 Cases.

BACKGROUND Hypercapnia is a known complication of laparoscopic surgery involving carbon dioxide (CO₂) pneumoperitoneum and is usually managed intraoperatively with ventilatory adjustments. However, delayed-onset postoperative hypercapnia is uncommon. Anemia impairs hemoglobin-mediated buffering and clearance of CO₂, potentially increasing vulnerability to postoperative respiratory acidosis. This report describes 2 cases of delayed-onset postoperative hypercapnia in anemic patients following total laparoscopic hysterectomy with CO₂ pneumoperitoneum, in the absence of subcutaneous emphysema. CASE REPORT Case 1: A 43-year-old woman with American Society of Anesthesiologists (ASA) physical status I and severe anemia (hemoglobin 7.3 g/dL) underwent laparoscopic hysterectomy. One unit of blood was transfused intraoperatively. Fifteen minutes after extubation, she experienced prolonged postoperative unresponsiveness. Arterial blood gas (ABG) showed significant respiratory acidosis with a partial pressure of arterial CO₂ (PaCO₂) of 88 mmHg. She needed reintubation and 2 hours of mechanical ventilation before full recovery. Case 2: A 45-year-old woman with ASA I and refractory anemia (hemoglobin 8.1 g/dL) underwent laparoscopic hysterectomy with intraoperative blood transfusion. Despite intraoperative hyperventilation for rising end-tidal CO₂ (>75 mmHg), she developed extended unresponsiveness following extubation. ABG detected severe hypercapnia (PaCO₂ 88 mmHg). She recovered using manual ventilation without reintubation. Neither patient showed signs of subcutaneous emphysema. CONCLUSIONS Delayed-onset hypercapnia can occur in anemic patients following laparoscopic surgery, despite standard ventilation protocols. Reduced hemoglobin-mediated CO₂ buffering, combined with ongoing CO₂ absorption after pneumoperitoneum may contribute to this presentation. Anemia should therefore be considered as a modifiable risk factor, and in high-risk patients, enhanced postoperative monitoring and individualized ventilation strategies should be considered.