Magnesium oxide (MgO) is a safe cathartic that rarely causes hypermagnesemia. Here, we report a schizophrenic patient case about loss of consciousness induced by hypermagnesemia due to MgO use. A 60-year-old man with schizophrenia had been taking antipsychotics and MgO for long time. After he had been constipated for 13 days, he defecated, then lost consciousness and developed hypotension. Hypermagnesemia (serum Mg level 20.2 mg/dL) was thought to be the cause of the circulatory collapse and loss of consciousness. Hemodialysis and intravenous calcium gluconate administration were performed. With his serum Mg level decrease, his condition improved. Mg is absorbed in the small intestine and excreted renally. Renal dysfunction and bowel hypomotility are the risk factors for hypermagnesemia. One of the side-effects of antipsychotics is ileus. If a patient takes both, Mg level could be high. Serum Mg level should be measured when a patient takes MgO and antipsychotics.

Objective: Vocal cord paralysis due to recurrent laryngeal nerve injury is a well-known complication in infants and children undergoing aortic arch reconstruction. The “gold standard” modality for examining vocal cords is direct flexible laryngoscopy; however, here we report our experiences with vocal cord ultrasonography after pediatric aortic arch reconstruction. Methods: Seven patients with voice hoarseness after aortic arch reconstruction at Hyogo Prefectural Kobe Children's Hospital between October 2017 and January 2019 underwent bedside ultrasonography for the assessment of vocal cord movement. Subsequently, flexible laryngoscopy was performed to confirm the ultrasonographic findings. Results: Aortic arch reconstruction was performed in five patients with coarctation of the aorta complex, one patient with interrupted aortic arch complex, and one patient with hypoplastic left heart syndrome. Vocal cord ultrasonography revealed left vocal cord paralysis in six patients and normal vocal cords in one patient. In six of the seven patients, the ultrasonographic findings corresponded with the results of flexible laryngoscopy. Median duration between postoperative tracheal extubation and bedside ultrasonography was 2 days. Conclusions: Bedside ultrasonography for vocal cord movement is useful for the early evaluation of postoperative vocal cord paralysis in infants and children. It can be used as an alternative to flexible fiberoptic laryngoscopy for the initial assessment of postoperative vocal cord function after pediatric cardiac surgery.