5. Respiratory - ALL

Respiratory Air Flow and Volume - Introduction

  • Spirometry Techniques

    • A method to record respiratory variables.

    • Analyzing recordings to derive respiratory parameters.

    • Examining lung volumes and capacities, basic pulmonary function tests, and simulating airway restrictions.

Learning Objectives

  • Describe the role of carbon dioxide (CO2) and H+ in breathing control.

  • Measure various lung volumes and capacities during inspiration and expiration.

  • Relate recorded lung volumes to a typical person of the same gender, height, and age.

  • Understand the role of chemoreceptors in ventilation regulation.

  • Perform pulmonary function tests and describe common measurements (PIF, PEF, FVC, FEV).

  • Describe the effects of airway restrictions on PIF, PEF, FVC, and FEV.

Respiratory Air Flow and Volume - Equipment Setup

  • Apparatus

    1. Components include spirometer pod, flow head, and PowerLab.

    2. Essential attachments: clean bore tubing, filter, and mouthpiece.

    3. Label mouthpiece with a name marker.

    4. Flow head adjustable for height.

    5. Spirometer measures pressure differences and air flow rates displayed as flow and volume.

    • CAUTION: Do not touch spirometer/flow head to avoid erroneous readings.

Respiratory Air Flow and Volume - Zeroing Spirometer Pod

  • Zeroing Process

    • Essential for accurate volume readings.

Steps to Zero Spirometer

  1. Adjust flow head height for comfortable use.

  2. Attach mouthpiece and filter.

  3. Click "Zero Spirometer" to reset flow channel baseline.

  4. Instruct subject to use a nose clip to ensure proper airflow through mouthpiece.

  5. Start recording and ensure subject breathes normally through the mouthpiece.

  6. Observe the recorded trace for downward deflection during expiration.

Respiratory Air Flow and Volume - Volume Correction

  • Volume Correction Need

    • Expired air is more voluminous than inspired due to warming and humidification (5-10% increase).

Procedure

  1. Zero the spirometer again.

  2. Start recording and have the subject breathe.

  3. Obtain sufficient data, marking comments during the recording.

  4. Perform forced expiration after normal tidal breathing and calculate volume correction factor (default is 1.08).

Respiratory Air Flow and Volume - Exercise 1: Lung Volumes and Capacities

  • Recording Normal Respiration

    • Subject must breathe without conscious control.

Procedures

  1. Zero Spirometer.

  2. Start recording, instruct subject to use nose clip and breathe normally for 1-2 minutes.

  3. Add comments for normal tidal breathing and lung volume procedure post deep breathing.

Respiratory Air Flow and Volume - Analysis: Lung Volumes and Capacities

  1. Calculate breaths per minute from tidal breathing data.

  2. Measure single tidal inspiration and enter into the table.

  3. Repeat for Inspiratory Reserve Volume (IRV) and Expiratory Reserve Volume (ERV).

  4. Calculate Residual Volume (RV) using provided calculators.

Respiratory Air Flow and Volume - Exercise 2: Pulmonary Functions Tests

  • Forced Vital Capacity (FVC)

    • Evaluating parameters of forced expiration.

Procedure

  1. Re-zero Spirometer before starting.

  2. Record normal breathing then execute forced expiration with comments for FVC procedure.

Respiratory Air Flow and Volume - Analysis: Pulmonary Function Tests

  1. Analyze the three FVC recordings.

  2. Measure Peak Inspiratory Flow (PIF) and Peak Expiratory Flow (PEF) and enter values.

  3. Calculate Maximal FVC value and Forced Expired Volume in 1 second (FEV1) to derive FEV to FVC ratio.

Respiratory Air Flow and Volume - Exercise 3: Simulating Airway Obstruction

  • Procedure for Simulation

    • Modifying setup to mimic bronchial obstructions (e.g. asthma).

Steps

  1. Remove filter, apply duct tape, create a small hole, and reattach filter.

  2. Perform FVC processes to gather obstructed breath data.

Respiratory Air Flow and Volume - Analysis: Simulating Airway Obstruction

  • Similar analysis steps as previous FVC testing.

Respiratory Air Flow and Volume - Maximum Breathing Capacity (MBC)

  • MBC Measurement

    • Tests maximum ventilation in 15 seconds.

Procedure

  1. Re-setup spirometer after obstruction test.

  2. Measure breath with rapid inhalation/exhalation for 15 seconds.

Respiratory Air Flow and Volume - MBC Analysis

  1. Measure air moved in 15 seconds using available markers.

  2. Calculate Maximum Breathing Capacity automatically based on input data.

Respiratory Air Flow and Volume - Breath Hold Times

  • Control of Ventilation Rate

    • CO2 and H+ affect ventilation via chemoreceptors.

Test Steps

  1. Hold breath, record duration.

  2. Hyperventilate for 1 minute, then hold breath again to see differences.

  3. Exercise to elevate heart rate, and perform breath hold once more.