• 
  

  • Peak flow measurements monitor asthma, in both acute and chronic cases.

  
  

  • Peak flow measurements can be used to assess severity, diurnal variation, response to bronchodilators, response to triggers (eg, viral illnesses, allergens), and effect of exercise.

  
  

  • Peak flow monitoring is useful at home, in the emergency department, and at the bedside to assess the severity of a patient’s asthma.

Absolute

• 
  

  • Pneumothorax.

  
  

  • Hemoptysis.

Relative

• 
  

  • Age; patients can usually perform maneuver starting between ages 4 and 5 years.

• 
  

  • Peak flow meter (Figure 18–1).