Table 2.

Comparison of crude diagnostic accuracy for reintubation at 7 days of the three models including 2341 patients recruited in five randomized trials [11, 12, 14, 15, 19]

	Se	Sp	PPV	NPV	Youden	Kappa
3 Factors model	62.96%	44.75%	19.26%	85.24%	0.08	0.04
4 Factors model	75.31%	36.31%	19.83%	87.55%	0.12	0.06
11 Factors model	84.20%	31.46%	20.44%	90.49%	0.16	0.07

Se sensitivity; Sp specificity; PPV positive predictive value; NPV negative predictive value

The 3-factors model included the following risk factors: age > 65y, chronic heart or pulmonary disease. The 4-factors model included the following risk factors: age > 65y, chronic heart or pulmonary disease, and prolonged mechanical ventilation. The 11-factors model included the following risk factors: age > 65 years, ≥ 2 comorbidities, prolonged mechanical ventilation, acute heart failure as the primary indication for mechanical ventilation, moderate-to-severe chronic obstructive pulmonary disease, APACHE II score > 12 on extubation day, airway patency problems, inability to deal with respiratory secretions, not simple weaning, obesity, or hypercapnia at the end of the spontaneous breathing trial