[Reversible cardiorespiratory failure induced by CO2 inhalation in cats].

Experiments on anesthetized cats showed that short-term inhalation of concentrated CO2 induced reversible asphyxia resulting in acute cardiorespiratory failure. The stage of hyperventilation was followed by apnea initially interrupted by primary gasps and by bradycardia and drop in systemic blood pressure. After termination of CO2 supply in the state of apnea or after onset of resuscitation the blood pressure started to increase, secondary gasps appeared and regular respiration was gradually restored. The rate and duration of gasps decreased but the inspiratory force and the achieved tidal volume and airflow were greater than at normal respiration. During reversible asphyxia induced by CO2 inhalation the ECG exhibited invariably severe arrhythmias, most frequently atrioventricular block of different degrees. Bilateral cervical vagotomy failed to prevent the occurrence of ECG changes. After administration of Indral, however, arrhythmias were recorded only exceptionally.