Breathing movements, airflow and arterial oxygen saturation were recorded in 6 infants aged 3 weeks to 7 months with apneic and cyanotic episodes associated with pertussis and compared with 12 healthy controls at the Dept of Paediatrics, Cardiothoracic Institute, Brompton Hospital, and Communicable Disease Unit, St George’s Hospital Medical School, London. Infants with pertussis had a greater frequency of apneic pauses, episodes of hypoxemia, and dips in oxygen saturation even during continued breathing movements. Apnea accompanied by mismatch between ventilation and perfusion of the lungs may produce the rapid onset of severe hypoxemia in infants with pertussis. Electroencephalographic recordings during prolonged pauses in inspiratory efforts with hypoxemia in one patient did not show a seizure discharge, but convulsions occurred in association with apnea and cyanosis in 4 patients. The twin sister of one patient, with an identical history of pertussis, died during a cyanotic convulsion while the infants were being brought to the hospital. That the convulsions are secondary to severe cerebral hypoxemia is suggested by these recordings and findings. 
COMMENT. This excellent study and method of investigation offers advantages over epidemiological research in demonstrating the potential hazards of pertussis in small infants and the need for early immunization and less toxic pertussis vaccines. In my experience, I have encountered no cases of convulsions as a result of pertussis in the USA, a reflection of the excellent compliance with immunization programs perhaps, while children with convulsive disorders related temporally to pertussis immunization have been referred to me often for nuerologic evaluation and treatment. DPT vaccine was listed as one of 7 drugs most commonly implicated in hospital admissions prompted by adverse reactions.