Go With the (Peak) Flow

A Clinical Swallow Evaluation is a series of screens that we use to determine if the patient requires more testing or not.

Let’s face it, whether we like it or not, insurance likes objective data, including numbers indicating a deficit or no deficit.   Peak Flow is a tool that gives us objective numbers to input into our reports.

What is Peak Flow?

A Peak Flow meter measures how fast air is expelled from the lungs in one fast blast.  A Peak Flow meter can be very beneficial to those with asthma.

Peak Flow also gives us information on the cough reflex and function of the cough, in turn, allowing us to determine patients that are at risk for penetration and/or aspiration.

Why do we care about coughing?

Coughing is a mechanism of airway clearance that adds to normal
ciliary function comprised of three events

  • Inspiratory effort
  • Followed by rapid vocal fold adduction
  • Contraction of the expiratory muscles

Respiratory Muscle Strength Training (RMST)

You can also use Peak Flow to determine baseline for RMST and to measure outcomes throughout your therapy using RMST.

So what has research told us about measuring Peak Flow?

We measure using PEF or Peak Expiratory Flow or PEFR Peak Expiratory Flow Rate.

  • Smith-Hammond, et al 2009-Peak flow identified 82% of aspirators
    (stroke patients) at PEF <2.9 L
  • Pitts, et al  2010-Peak flow identified 86% of aspirators (Parkinson’s) at
    PEF <5.2 L
  • Suarez, et al 2002 identified 74% aspirators (ALS) at
    <4.0 L
  • Plowman, et al 2016 identified voluntary cough airflow in patients with ALS at risk for penetration/aspiration

Peak Flow meters can be purchased to use.

PF 1        PF 2

A less expensive Peak Flow model will have a plastic piece on the side that moves as the person exhales or coughs into the device.   You can determine the PEF or PEFR by having the person exhale or cough into the device 3 times and figuring the average rate.

PF 3

You can also purchase a digital device which will give you a more accurate reading, but will cost you a bit more.

These devices can be purchased on Amazon or a medical supply store.   You can often purchase disposable mouth pieces so that you can use the device with multiple patients after cleaning.

References:

Gregory, S. A. (2007). Evaluation and management of respiratory muscle dysfunction in ALS. NeuroRehabilitation22(6), 435-443.

Hammond, C. A. S., Goldstein, L. B., Horner, R. D., Ying, J., Gray, L., Gonzalez-Rothi, L., & Bolser, D. C. (2009). Predicting aspiration in patients with ischemic stroke: comparison of clinical signs and aerodynamic measures of voluntary cough. Chest135(3), 769-777.

Pitts, T., Troche, M., Mann, G., Rosenbek, J., Okun, M. S., & Sapienza, C. (2010). Using voluntary cough to detect penetration and aspiration during oropharyngeal swallowing in patients with Parkinson disease. Chest138(6), 1426-1431.

Plowman, E. K., Watts, S. A., Robison, R., Tabor, L., Dion, C., Gaziano, J., … & Gooch, C. (2016). Voluntary cough airflow differentiates safe versus unsafe swallowing in amyotrophic lateral sclerosis. Dysphagia31(3), 383-390.

Suárez, A. A., Pessolano, F. A., Monteiro, S. G., Ferreyra, G., Capria, M. E., Mesa, L., … & De Vito, E. L. (2002). Peak flow and peak cough flow in the evaluation of expiratory muscle weakness and bulbar impairment in patients with neuromuscular disease. American journal of physical medicine & rehabilitation81(7), 506-511.

 

 

 

 

 

 

 

 

 

2 thoughts on “Go With the (Peak) Flow

  1. Thank you this is helpful! I am an SLP hoping to use this in the hospital setting, I was wondering if you have the values of peak flow that would indicate possible aspiration risk?

    1. There’s not really a scale that indicates aspiration risk. You’re more looking at strength of the cough and want that to fall in the normal ranges. The cough strength is what you want to prevent aspiration.

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