Although use of dexmedetomidine was associated with a greater duration of NIV vs placebo ( 37 [ 16-72 ] vs. 12 [ 4-22 ] h , P = .03 ) , the total ventilation duration ( NIV + invasive ) was similar ( 3.3 [ 2-4 ] days vs. 3.8 [ 2-5 ] days , P = .52 ) .