- Has not had first attempt at extubation(extubation readiness requires fulfilling of all the following criteria: a. Having received at least one loading dose of 20 mg/kg and 5 mg/kg daily maintenance dose of caffeine citrate; b. pH>7.20 PaCO2<=60 mmHg (these may be evaluated by arterialized capillary blood gas analysis or appropriately calibrated transcutaneous monitors. Venous blood gas values cannot be used); c. Paw <=7-8 cmH2O; d. FiO2<=0.30; e. sufficient spontaneous breathing effort, as per clinical evaluation).;