Hypercapnia and severe hyperkalemia following robot-assisted endoscopic thyroid surgery: A case report

Background: Robot-assisted thyroidectomy has been widely performed because it has many advantages, such as less invasiveness and better cosmesis. Due to the need to inject carbon dioxide (CO 2 ) into the neck skin during the operation, the incidence of subcutaneous emphysema and hypercapnia is increased. Thalassemia, which is a type of haemolytic anaemia caused by the lack of globin chain synthesis, causes damage, instability and fragility of the erythrocyte membrane and can easily lead to haemolysis and hyperkalaemia due to changes in pH. Hypercapnia is a complication of endoscopic surgery, but severe hyperkalaemia is rare that we suspect it may be related to the patient's history of thalassemia. Here, we report this case and analyse the possible causes described in the literature to improve the anesthetic management of patients undergoing thyroidectomy or thalassemia in the future. Clinical features: A 30-year-old man who was scheduled for robot-assisted thyroidectomy received general anaesthesia. Ninety minutes after CO 2 injection, his end-expiratory carbon dioxide (PetCO 2 ) suddenly increased to 45 mmHg, and arterial blood gas analysis (ABG) showed serious abnormalities. He developed severe hypercapnia and hyperkalemia during the operation. The patient gradually recovered after hyperventilation and sodium bicarbonate treatment. Conclusion: Hypercapnia and subcutaneous emphysema are severe complications of robot-assisted endoscopic thyroid surgery. Anesthesiologists should conduct an ABG right away and make a diagnosis immediately when facing this crisis. Patients with thalassemia, which easily leads to haemolysis and hyperkalemia due to changes in pH, should carefully select endoscopic surgery requiring CO 2 .