Ventilation in awake rats with permanent arterial catheters.

Respiratory frequency (f), tidal volume (VT) and minute ventilation (VE) were measured in restrained awake rats using a volumetric body plethysmograph excluding the head. An arterial catheter was then implanted and ventilatory measurements performed again two or three days later. Arterial blood gases and acid-base status were measured before entry in the plethysmograph (control values) and after, accompanying each ventilatory measurement. The pattern of ventilation (VT and VE) was significantly correlated with the respiratory status, particularly with PaCO2 (P less than 0.001). A ventilatory (VE, VT, f) and respiratory (PaO2, PaCO2, pH) steady state was obtained from the fifteenth minute to the end of the observation period. The present preparation is a stable experimental model providing respiratory and ventilatory data in the awake rat.