spirometer Kaveh Roshanbin far 8533046 What is it

spirometer Kaveh Roshanbin far 8533046

What is it? �Spirometry is the measurement of the flow and volume of air entering and leaving the lungs �Test of pulmonary function (PFT) • Indicator of health status or disease • Exercise fitness

Respiration �Respiratory system is functions include gas exchange , p. H regulation, vocalization , and protection from foreign substances. �Respiration: �Cellular is the cellular mechanism of energy conversion �External is the exchange of gases between atmosphere and cells, Includes ventilation, gas exchange at lungs and cells, and transport of gases in the blood.

Ventilation The process of exchange of air between the lungs and the ambient air � Airflow in respiratory system is directly proportional to the pressure gradient and inversely related to the resistance of the airways. � A single respiratory cycle = inspiration + expiration

Inspiration � Lung air pressure < Atmosphere air pressure �Diaphragm & inspiratory muscles contract → �Thoracic cavity expands → negative pressure → �air flows into lungs

Expiration �Passive process resulting from natural elastic recoil of the expanded lung walls. � During rapid breathing, internal intercostal and abdominal muscles contract to help force air out at a more forceful, rapid rate

Static lung volume and capacities Tidal volume TV The volume of air inhaled & exhaled at each breath during normal quiet breathing Inspiratory reserve volume IRV The volume of air that can be forcefully inspired following a normal quiet inspiration Expiratory reserve volume ER V The volume of air that can be forcefully expired after a normal or resting expiration Vital capacity VC The maximum amount of air that can be exhaled after the fullest inspiration possible (TV + ERV + IRV) Inspiratory capacity IC The maximum amount of air that can be inhaled after a normal exhalation (TV + IRV) Residual volume RV The volume of air remaining in the lungs after a forceful expiration Total lung capacity TL C The total volume of the lungs (VC + RV) Functional residual capacity FR C The amount of air remaining in the lungs after a normal quiet expiration (ERV + RV)

Lung volumes & capacities depend on: �Age � Body size (height & weight) � Gender � Pulmonary health � Altitude(height) � Irritants

Forced vital capacity FVC The total volume expired by a forced maximal Expiraion from a position of maximal inhalation Forced expiratory volume in 1 sec FEV 1. 0 The volume of air expired in the first second of maximal forced expiration from a position of full inspiration Forced expiratory flow from 25 -75% of exhalation FEF 25 - The average flow rate during the middle 50% of the 75 forced vital capacity maneuver Or Maximum Mid-Expiratory Flow (MMEF)

Calculating FVC

Calculating FEV 1. 0

Calculating FEF 25 -75

Calculating FEF 25 -75%

Volumes and Flow varies by Gender, Age, Height and Ethnicity…

Spirometer Apparatus used to measure static & dynamic lung volumes/capacities using a closed system • Registers the amount and rate of air moved into or out of the lungs • 2 main types; 1. Volume: records the amount of air exhaled or inhaled within a certain time* 2. Flow: measures how fast the air flows in or out as the volume of air inhaled or exhaled increases

Volume spirometers �Key features: � Real time tracings record volume in relation to time

Advantages – Volume Spirometers �Some are portable versions � Leak tests and calibrations are easy to perform � Many can produce flow/volume curves and loops with the addition of special electronic or digital circuitry. � Volume spirometers hold their calibration months to years better than flow spirometers

Disadvantages – Volume Spirometer �Not practical by hand to determine peak expiratory flow or instantaneous volumes, �Coughs and submaximal efforts are not as obvious � Some are heavy, cumbersome and may be prone to fostering mold or bacterial growth if not cleaned properly

Flow Spirometers Key features � Measure how quickly air flows past a detector and then derives the volume by electronic means. � Records flow rate at brief intervals (30 -300 x/sec) and use data to reconstruct the flow rate at each point in time and volume (digitization). � Tracings measure flow in relation to volume

Advantages – Flow Spirometer � Computer can produce volume-time tracings � Tend to be lighter and more portable � Disposable, single-use flow sensors, available on some floe spirometers eliminate the risk (low) of cross-contamination.

Disadvantages – Flow Spirometer � No real-time or hard copy tracings � Reliance on electronic equipment �FEV 1. 0 cannot be calculated by hand unless the time is indicated in seconds on a flow-volume tracing � Some flow spirometers are more difficult to calibrate and may lose their calibration over time if not well maintained

Limitations of Spirometry � Test results are not disease specific � May not be sensitive enough to show abnormalities before extensive and in some cases irreversible damage has been done (mostly for restrictive diseases) ∴ Should not be used as the sole screening tool of a respiratory surveillance program.

WHAT we find… �Obstructive deficits �Restrictive deficits �Mixed deficits

Obstructive deficits �A reduction of FEV 1 � In relation to the forced vital capacity will result in a low FEV 1/FVC% �The lower limit of normal for FEV 1/FVC is around 7075% � The exact limit is dependent on age.

Restrictive deficits �Normal or high FEV 1/FVC% ratio � Reduction in both FEV 1 and FVC �Interstitial lung disease � Respiratory muscle weakness �Thoracic cage deformities such as kypho-scoliosis

Mixed deficits �A combination of both obstruction and restriction resulting in gas trapping, rather than as a result of small lungs. �A reduced FVC together with a � low FEV 1/FVC% ratio �It is necessary to measure the patient's total lung capacity to distinguish between these two possibilities.

Severity of Airway Obstruction FEV 1 (% of Predicted) Mild >70 Moderate > 60 and < 70 Moderately severe > 50 and < 60 Severe > 34 and < 50 Very severe < 34 Severity of Chest Restriction* FVC (% of Predicted) Mild >70 but < LLN Moderate > 60 and <70 Moderately severe > 50 and < 60 Severe > 34 and < 50 Very severe < 34

Type of response FEV 1 FVC FEV 1/FVC % Normal > 80 % > 75 % Obstructive < 80 % > 80 % < 75 % Restrictive > 80 % < 80 % >75 % Mixed < 80 % < 75 %

Thanks for your attention