Nava Ann Intern Med 1998; 128:721
•COPD ARF, multicenter, weaning
•T-piece trial after 48 hour MV
• • Passed extubated
• • Failed randomized
• • NIPPV
• • PS
•By day 60:  22/25 NIPPV
•   (weaned)  17/25 PS
•Duration of MV: 16.8 + 11.8 PS
•   (P = 0.02)        10.2 + 6.8 NIPPV