Common
• Status asthmaticus
• Acute exacerbation of COPD
• Pneumonia (especially in immunocompromised or immunodeficiency patients such as HIV disease and alcoholics)
• Acute laryngotracheobronchitis (Croup)
• Acute LVF (due to MI, pericarditis, cardiac tamponade, fulminant myocarditis)
• Arrhythmias (VT, AF, VF)
• Psychogenic (hyperventilation syndrome).

Occasional
• Spontaneous or tension pneumothorax
• Massive pleural effusion (tubercular, malignant)
• Massive lobar collapse (traumatic, post-
operative)
• Massive pulmonary embolism(PE)
• Metabolic acidosis (DKA, uremia, salicylate
overdose)
• Anaphylaxis (angioneurotic edema)
• Severe acute respiratory syndrome (SARS).
Rare
• Foreign body aspiration
• Drug induced (NSAIDs, beta blockers)
• Acute respiratory distress syndrome (ARDS)
• Neurologic (CVA, Guillain-Barré syndrome,
Bulbar polio)
• Pacemaker syndrome.