Comparative Effects of Different Noninvasive Ventilation Mode on Neural Respiratory Drive in Recovering AECOPD Patients

Methods: After the baseline data of spontaneous breathing was collected, 20 hypercapnic recovering AECOPD patients were placed on different mode of noninvasive positive pressure ventilation(NPPV, such as the PAV or PSV mode) randomly. For each mode, three levels (PA-, PA, PA+or PS-, PS, PS+), ) of support were applied.PS and PA are set for the patient's comfort . On the basis of these two levels, 25% increase and reduction assisted level of pressure were set both for PS and PA (PA-, PA+or PS-, PS+). At each level, the patients were ventilated at least 20 minutes until the breathing was stable. The respiratory frequency (RR), tidal volume (VT), transdiaphragmatic pressure (pdi) the pressure-time product (PTP) and root-mean-square(RMS) of EMGdi were calculated. Esophageal and gastric balloon-catheters were used to detect the intra-thoracic and abdominal pressure. Airway pressure was also measured simultaneously. EMGdi was recorded from a multipair esophageal electrode .During ventilation Airflow and ventilation were measured with pneumotachograph.

Inclusion criteria

• Clinical diagnosis of the COPD (Chronic Obstructive Pulmonary Disease) the COPD patients were all in stable condition during recovery from acute exacerbation.

Exclusion criteria

• severe Cardiovascular disease
• Pneumonia
• neuromuscular and chest wall deformity
• Respiratory arrest
• Cardiovascular instability (hypotension, arrhythmias, myocardial infarction)
• Change in mental status; uncooperative patient
• High aspiration risk
• Viscous or copious secretions
• Recent facial or gastroesophageal surgery
• Craniofacial trauma
• Fixed nasopharyngeal abnormalities
• Burns
• Extreme obesity