Hyperbaric oxygen for paroxysmal sympathetic hyperactivity syndrome after acute carbon monoxide poisoning

Abstract

JOURNAL/mgres/04.03/01612956-202603000-00002/figure1/v/2025-06-28T140100Z/r/image-tiff Paroxysmal sympathetic hyperactivity syndrome (PSH) is common in patients with severe craniocerebral injuries. Carbon monoxide poisoning (ACOP) may lead to secondary PSH, and hyperbaric oxygen (HBO) is an important treatment method for ACOP that can promote the dissociation of carboxyhemoglobin and reduce the long-term sequelae of ACOP. To explore the risk factors and clinical characteristics of PSH secondary to acute ACOP and to investigate the efficacy of HBO treatment, a retrospective analysis was performed on patients with moderate to severe ACOP admitted to the Hyperbaric Oxygen Department of Beijing Chaoyang Hospital, Capital Medical University, from January 1, 2018 to December 31, 2024. Three patients developed PSH during hospitalization and were classified into the PSH group, while the remaining 50 patients were in the non-PSH group. Univariate Fisher's exact test indicated that a coma duration of more than 72 hours was related to the occurrence of PSH after ACOP, and irregular HBO treatment after onset might be associated with the occurrence of PSH after ACOP. All three PSH patients developed paroxysmal postural or dystonic disorders after onset, accompanied by sympathetic excitation manifestations such as increased heart rate, respiratory rate, elevated blood pressure, and fever. Antiepileptic drugs had poor effects, and the attacks were effectively controlled after HBO treatment combined with adjusted drug therapy. The results indicate that for patients with severe carbon monoxide poisoning, especially those with a long coma duration or irregular HBO treatment after onset, if epileptic seizures occur during the disease course and are accompanied by sympathetic excitation manifestations, the possibility of PSH should be considered. Regular HBO treatment is of great significance for controlling the onset of symptoms.

Keywords: blood pressure; carbon monoxide poisoning; epileptic seizure; fever; heart rate; hyperbaric oxygen; paroxysmal sympathetic hyperactivity syndrome; postural or dystonic disorders; respiratory rate; sweating.