Expiration-like movement and spino-bulbo-spinal reflex in a patient with apneic coma caused by anoxic encephalopathy

A 72-year-old female patient, hospitalized for parkinsonism, suffered cardiopulmonary arrest without any certain causes. The patient was successfully resuscitated and her life was sustained by artificial ventilator for 100 days. All brainstem reflexes were absent, and flat electroencephalogram and no response of brainstem auditory evoked potentials were confirmed twice with an interval of over 6 hours. Flexion of the arm induced reflex rectus abdominis muscle contraction, resembling expiratory movement. Muscle stretch reflexes on rectus abdominis were hyperactive. The expiration-like movement appeared in an apnea test seven minutes after a cessation of artificial ventilation. Electrical stimuli on femoral nerve induced complex action potentials with a 70.2±6.9msec latency and 300msec duration in rectus abdominis muscle, which were similar to the spino-bulbo- spinal reflex. Single photon emission tomography showed only slight cerebral cortical blood flow. The expiration-like movements observed in this case suggest a relationship not only with the spinal cord reflex but also with polysynaptic reflexes related to reticular formation in the medulla oblongata.