Impact of HI-NPPV Vs LI-NPPV on Tolerance Among AECOPD Patients

In the high-intensity NPPV group, IPAP is initially adjusted in increments/decrements of 1-2 cmH2O, typically ranging from 20 to 30 cmH2O (or a tolerated maximum), to obtain a VT 10-15 mL/kg PBW and a respiratory rate \<25 breaths/min. Subsequent adjustments to IPAP are based on the results of arterial blood gases (ABGs; up to 30 cmH2O) to achieve normocapnia (if possible), or to maximally decrease PaCO2 toward normocapnia if normocapnia can not be achieved. If PaCO2 decreases to less than 35 mmHg, IPAP will be decreased to achieve normocapnia.

In the low-intensity NPPV group, as well as during the 6-hour trial of low-intensity NPPV, IPAP is initially adjusted in increments/decrements of 1-2 cmH2O (up to 20 cmH2O), according to patients' tolerance, to obtain a VT 6-10 mL/kg PBW and a respiratory rate \<25 breaths/min. Subsequent adjustments to IPAP are based on the results of ABGs (up to 20 cmH2O) to achieve a pH of ≥7.35 and to reduce PaCO2 to a level deemed appropriate by the attending physician.