FAIL TO WEAN 
Fluid overload
Airway resistance (small ETT, mucous plug, etc.)
Infection
Lying down (elevate HOB)
Thyroid, Toxicity (meds)
Oxygenation insufficient
Wheezing (nebs for asthma/COPD)
Electrolyte abnormality (including Mg/Phos), Eating (nutrition)
Anti-inflammatories (steroids in asthma/COPD)
Neuromuscular disease, Neuro status compromised
Weaning mechanical ventilation
Adjusting mechanical ventilation settings
Awake intubation
Delayed sequence intubation
Mechanical ventilation 
IV fluid resuscitation
Lung recruitment maneuver
Pulmonary antibiotics