1 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

2 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 27 Wave Form Analysis

3 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Common Wave Forms Three typical wave forms: –Pressure –Flow –Volume Other wave forms: –Pressure versus volume –Flow versus volume

4 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Wave Form Morphologies Rectangular Accelerating Decelerating Sinusoidal Oscillating

5 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Analysis of Specific Wave Forms Specific waveforms (scalar or loops) are helpful to analyze changes in the patient’s pathology and to assess the patient’s response to positive pressure ventilation. –Airway resistance, lung compliance, overdistension and other key information may be readily assessed.

6 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Pressure Versus Time Observation of this graphical display allows determination of: –Patient effort –Peak and plateau pressures –Adequacy of inspiratory flow –Mandatory (ventilator) versus spontaneous breath types

7 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Flow Versus Time Helps to assess the: –Inspiratory flow pattern –Air trapping –Airway resistance

8 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Volume Versus Time Analysis of this graphical display allows the determination of: –Tidal volume –Detection of air trapping –Identification of breath type

9 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Combined Wave Forms The two most common combined wave forms are: –Pressure versus volume –Flow versus volume loops Presents information for each scalar relative to each other and to time

10 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Pressure Versus Volume Helpful in determining: – Tidal volume – Inspiratory work – Detecting overdistention – Changes in compliance and resistance

11 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Flow Versus Volume Flow-volume loops are helpful in assessing: –Changes in airway resistance –Spirometry readings

12 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Wave Form Interpretation Wave form interpretation is a necessary skill. –Use theoretical concepts and bedside practice to learn to interpret wave forms –Wave form interpretation is largely learned through repeated practice

13 © 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Critical Criteria for Appropriate Wave Form Selection Depending on the clinical question: –Changes in airway resistance may be assessed using both the volume- pressure and flow-volume graphical displays –Changes in hysteresis (volume- pressure) and peak flow (flow-volume) are indicative of changes in airway resistance