Respiratory frequency control during external elastic loading and chest compression.

Experiments were conducted to determine if extravagal (i.e. chest wall) respiratory mechanoreceptors are involved in the control of respiratory frequency during steady-state external elastic loading (EEL) and chest compression (CC) in the anesthetized (Dial), vagotomized cat and dog. Frequency versus PaCo2 curves obtained by breathing CO2 mixtures were compared with curves obtained during elastic loading and chest compression. There was no significant difference between the CO2 and EEL curves in cats or dogs indicating there is no extravagal mechanoreceptor information contributing to the control of respiratory frequency during EEL. Comparison of curves obtained with chest compression and CO2 breathing show that dogs respond to chest compression with an extravagal (i.e. involving chest wall mechanoreceptors) neural reflex increase in frequency.