Noninvasive ventilation (NIV) refers to the administration of ventilatory suppo without using an invasive aificial airway (endotracheal tube or tracheostomy tube). The use of noninvasive ventilation (see the video below) has markedly increased over the past two decades, and noninvasive ventilation has now become an integral tool in the management of both acute and chronic respiratory failure, in both the home setting and in the critical care unit. Noninvasive ventilation has been used as a replacement for invasive ventilation, and its flexibility also allows it to be a valuable complement in patient management. Its use in acute respiratory failure is well accepted and widespread. It is the focus of this review. The role of noninvasive ventilation in those with chronic respiratory failure is not as clear and remains to be defined. The key to the successful application of noninvasive ventilation is in recognizing its capabilities and limitations. This also requires identification of the appropriate patient for the application of noninvasive ventilation (NIV). Patient selection is crucial for the successful application of noninvasive ventilation. Once patients who require immediate intubation are eliminated, a careful assessment of the patient and his or her condition determines if the patient is a candidate for noninvasive ventilation. This requires evaluation on several levels, and it may involve a trial of noninvasive ventilation. The following variables and factors help identify patients who may be candidates for noninvasive positive-pressure ventilation. Absolute contraindications are as follows: Coma Cardiac arrest Respiratory arrest Any condition requiring immediate intubation Other contraindications (rare exceptions) are as follows: Cardiac instability - Shock and need for pressor suppo, ventricular dysrhythmias, complicated acute myocardial infarction GI bleeding - Intractable emesis and/or uncontrollable bleeding Inability to protect airway - Impaired cough or swallowing, poor clearance of secretions, depressed sensorium and lethargy Status epilepticus Potential for upper airway obstruction - Extensive head and neck tumors, any other tumor with extrinsic airway compression, angioedema or anaphylaxis causing airway compromise Other considerations that may limit application are as follows: Implementation - Staff learning curve and time requirements (nursing and respiratory therapy), potential for delay in definitive therapy (limit trials of therapy) After eliminating unsuitable candidates for noninvasive ventilation, successful application of noninvasive ventilation mandates close assessment and selection of patients and identification of conditions best suited for treatment. Not all patients with diagnoses capable of management with noninvasive ventilation (eg, Patient inclusion criteria are as follows: Patient cooperation (an essential component that excludes agitated, belligerent, or comatose patients) Dyspnea (moderate to severe, but sho of respiratory failure) Tachypnea (>24 breaths/min) Increased work of breathing (accessory muscle use, pursed-lips breathing) Hypercapnic Hypoxemia (PaO2/FIO2< 200 mm Hg, best in rapidly reversible causes of hypoxemia) NIV is indicated in adults as follows: Obstructive sleep apnea syndrome. Chronic obstructive pulmonary disease with exacerbation. Bilateral pneumonia. Acute congestivehea failure with pulmonary edema. Neuromuscular disorders. Acute lung injury/ Acute respiratory distress syndrome.