Monitoring peak flow

Monitoring peak flow - monitoring a client’s peak flow levels gives an indication of respiratory function and facilitates objective evaluation of treatment, for example nebulizer therapy. A peak flow recording is defined as a measurement of the amount of air that can be forcibly exhaled and is used to monitor respiratory function. Bear in mind that peak flow measurement should not be attempted on patients in severe respiratory distress.

Equipment:
The equipment needed to monitor peak flow consists of a peak flow meter and mouthpiece and an appropriate chart for recording the results. The procedures and rationales are given below.

Procedure	Rationale
Explain procedure and ensure adequate understanding	To promote client co-operation and obtain informed consent
Assist client into an upright position	To promote lung expansion
Fix mouthpiece to peak flow meter	To ensure correct assembly of equipment
Ensure the pointer is at zero	To ensure accurate reading is obtained
Hold meter, ensuring that fingers are clear of the scale and the holes in the base of the meter	To ensure accurate reading is obtained
Instruct client to take a deep breath	To fill lung fields to capacity with air to be exhaled
Instruct the client to hold the meter horizontally	To obtain accurate reading
Instruct client to place the mouthpiece in their mouth and close lips securely around it	To create a seal around the mouthpiece and thus prevent air leakage
Instruct client to exhale as hard as possible into the meter and sustain this for as long as possible	To expel as much air as possible
Note the number on the scale	To monitor peak flow and compare to the norm. Norm values depend on age, height and gender, e.g. Boy aged 9, 1.47 m = 350 litres/min Woman aged 30, 1.60 m = 475 litres/min Man aged 50, 1.75 m = 600 litres/min
Return pointer to zero	To prepare for second attempt
Repeat procedure twice more	To obtain highest score from three attempts
Reposition the client	To promote client comfort
Record scores on appropriate chart and report any deviation from the norm	Legal requirement to maintain documentation and safeguard the client through good communications
Wash mouthpiece in warm water with a mild detergent and dry thoroughly unless disposable	To prevent cross-infection