Nemer et al used the Integrative Weaning Index (IWI) to identify a patient who can be successfully weaned from mechanical ventilation. The authors are from the Hospital de Clinicas de Niteroi and Federal University of Rio de Janeiro in Brazil.



(1) static compliance in mL per cm water

(2) oxygen saturation of arterial blood in percent

(3) respiratory rate (f) in breaths per minute

(4) tidal volume (Vt) in liters


ratio of f to Vt =

= (respiratory rate) / (tidal volume)



= (static compliance) * (oxygen saturation) / (ratio of f to Vt)



• An IWI >= 25 mL per cm water / breaths / minute / liter was associated with successful weaning.



• The sensitivity was 97% and specificity 94%.

• The positive predictive value was 99% and negative predictive value 86%.

• The diagnostic accuracy was 97%.


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