From the Guidelines
Upper airway obstruction should be ruled out in patients with dyspnea, and clues to its presence include dysphonia, inspiratory stridor, monophonic wheezing, normal PaO2, and complete resolution of airflow obstruction with intubation. When assessing a patient with suspected upper airway obstruction, a brief physical examination should be performed to evaluate the severity of the exacerbation and overall patient status, including level of alertness, fluid status, presence of cyanosis, respiratory distress, and wheezing 1. The physical examination should also identify any possible complications, such as pneumonia, pneumothorax, or pneumomediastinum.
Key Points to Consider
- Upper airway obstruction can be caused by foreign bodies, epiglottitis, organic diseases of the larynx, vocal cord dysfunction, and extrinsic and intrinsic tracheal narrowing 1
- Flow-volume curves and laryngoscopy should be used to evaluate patients with suspected upper airway obstruction, either during or after the ED visit, depending on the severity of the obstruction 1
- A healthy upper airway microbiome is important for preventing colonization by pathogenic organisms and maintaining respiratory health
- Disruptions to the upper airway microbiome can lead to respiratory infections and exacerbate conditions like asthma and COPD
Diagnostic Approach
- Patients with suspected upper airway obstruction should undergo a thorough physical examination and diagnostic testing, including flow-volume curves and laryngoscopy 1
- The diagnosis of upper airway obstruction should be made based on a combination of clinical presentation, physical examination, and diagnostic test results 1
From the Research
Upper Airway Obstruction
- Upper airway obstruction is a potentially fatal condition that requires prompt diagnosis and treatment 2
- Common causes of upper airway obstruction include foreign body aspiration, infections, and sequelae of intubation, tracheostomy, and transtracheal oxygen catheters 2
- Spirometry is an insensitive test for diagnosing upper airway obstruction and reflects the functional, rather than anatomic, severity of an obstruction 2
Diagnosis of Upper Airway Obstruction
- CT and magnetic resonance imaging scans are useful additions to the diagnostic armamentarium for upper airway obstruction 2
- Several quantitative and visual criteria can be used to detect upper airway obstruction via flow-volume loops, including the ratio of forced expiratory volume in the first second (FEV(1)) to maximum expiratory flow (MEF) and the presence of a plateau or biphasic shape 3
- The aggregate sensitivity for detecting upper airway obstruction using these criteria is 69.4% 3
Management of Upper Airway Obstruction
- Direct laryngoscopy is a procedure that allows for the direct visualization of the larynx and can be used for airway management 4
- Alternative intubation techniques, positioning, laryngoscopy blades, and stylets can be used to facilitate direct laryngoscopy 4
- Pharmacologic adjuncts can be used to help manage the difficult airway 4