Known or Suspected Asthma Clinical Pathway — Primary Care

Spirometry Guidance

Spirometry Maintenance	Calibrate spirometer in the morning or before time of procedure
General Guidance	Mouth must be tightly around mouthpiece Goal is for the child to forcefully breathe out into the mouthpiece for at least 4 secs; this requires a lot of coaching Child does not need to inhale at the end of expiration Unacceptable techniques Unsatisfactory start or hesitation Cough that occurs during the first sec of the effort An effort that is less than 3 secs A leak around the mouthpiece Obstruction of mouthpiece by tongue, gum, etc. Test child 3 times The computer should use the best effort to generate the flow-volume and volume-time curves Print out both flow-volume loop and volume-time curve Report back verbally to physician if child is unable to complete test
Contraindications	Recent bronchodilator Symptoms that might exclude testing (uncontrolled coughing or wheezing, inability to follow directions or control breath).
Patient Position	Tight clothes should be loosened Standing Stand up straight, feet about a foot apart Chair nearby Sitting Sit up straight Both feet on floor; uncrossed
Nursing Coaching	Explain why spirometry is needed Indications for spirometry: new diagnosis of asthma, to measure reversibility, to measure control after treatment initiated Explain what spirometry does Measures airflow through your airways Demonstrate that child’s mouth must be tight around the mouthpiece Demonstrate practicing with a pinwheel or party favor Explain proper nose-clip insertion Explain and encourage the child to take the deepest breath possible Say, “Place the mouthpiece in your mouth, seal your lips around it, and blast out all the air in your lungs as fast and hard as possible. Continue blowing out until asked to stop.” Coach the child through the entire process Ask the child to keep their eyes on you Test will be repeated 3 times

Spirometry Results Interpretation

FVC (Forced Vital Capacity)	The total amount of air that one can exhale after taking a forced expiration
FEV1 (Forced Expiratory Volume)	The amount of air that is exhaled in the first second of forced expiration; best predictor of normal lung function Primarily indicates the patency of large airways but may indicate small airway function as well
FEF (Forced Expiratory Flow) Max or PEF (Peak Expiratory Flow)	The maximum amount of air exhaled during forced expiration Expressed in liters/sec Peak-flow meter values are expressed in liters/minute Multiply by 60 in order to compare the two values
FEF 25-75%	The mid-expiratory flow The least effort-dependent measurement and indicates airflow in smaller airways A decrease in this value will be expressed as a concave dip in the downward slope of the flow-volume loop
FEV1/FVC	The ratio of FEV 1 to FVC > 80-85% predicted is considered to be within normal limits

Spirometry Curves

Review Spirometry Curve Examples

If you have questions about any of the clinical pathways or about the process of creating a clinical pathway, please contact us.

©2024 by Children's Hospital of Philadelphia, all rights reserved.
Use of this site is subject to the Terms of Use.

The clinical pathways are based upon publicly available medical evidence and/or a consensus of medical practitioners at The Children’s Hospital of Philadelphia (“CHOP”) and are current at the time of publication. These clinical pathways are intended to be a guide for practitioners and may need to be adapted for each specific patient based on the practitioner’s professional judgment, consideration of any unique circumstances, the needs of each patient and their family, and/or the availability of various resources at the health care institution where the patient is located.

Accordingly, these clinical pathways are not intended to constitute medical advice or treatment, or to create a doctor-patient relationship between/among The Children’s Hospital of Philadelphia (“CHOP”), its physicians and the individual patients in question. CHOP does not represent or warrant that the clinical pathways are in every respect accurate or complete, or that one or more of them apply to a particular patient or medical condition. CHOP is not responsible for any errors or omissions in the clinical pathways, or for any outcomes a patient might experience where a clinician consulted one or more such pathways in connection with providing care for that patient.