Is weaning failure caused by low-frequency fatigue of the diaphragm?

Because patients who fail a trial of weaning from mechanical ventilation experience a marked increase in respiratory load, we hypothesized that these patients develop diaphragmatic fatigue. Accordingly, we measured twitch transdiaphragmatic pressure using phrenic nerve stimulation in 11 weaning failure and 8 weaning success patients. Measurements were made before and 30 minutes after spontaneous breathing trials that lasted up to 60 minutes.

Unilateral expiratory airflow obstruction during forced exhalation.

We present a case of unilateral airflow obstruction during forced exhalations. The patient presented with episodic dyspnea and wheezing, particularly when he lay in the right lateral decubitus position. Spirometry revealed symmetric, marked reductions in forced expiratory volume in the first second and forced vital capacity values, while plethysmography demonstrated a near-normal total lung capacity.