Variability of patient-ventilator interaction with pressure support ventilation in patients with chronic obstructive pulmonary disease.

摘要: In 12 patients with chronic obstructive pulmonary disease (COPD) receiving pressure support ventilation (PSV), we studied the variability of respiratory muscle unloading and defined its physiologic determinants using a modified pressure-time product (PTP). Inspiratory PTP/min decreased as PSV was increased (p 0.6 L in predicting this threshold < 0.001). At 20 cm H2O, expiratory effort, quantitated by an PTP, clearly evident five before cessation inspiratory flow, signifying that patient "fighting" ventilator; note, these had frequency or = 30 breaths/min. conclusion, patient-ventilator interactions COPD are complex, events expiration need to be considered addition those inspiration.