Weaning from mechanical ventilation is a critical component of ICU care. Early weaning is important to avoid complications of prolonged mechanical ventilation, such as ventilator induced lung injury, ventilator associated pneumonia, increased duration and cost of ICU stay. Difficult weaning is caused by disease factors (e.g. respiratory, cardiac, metabolic, and neuromuscular) and clinician management factors (e.g. failing to recognize readiness to wean and inappropriate ventilator settings).