Rapid Interpretation of Ventilator Waveforms Book

CONTENTS

PREFACE vii

1. VENTILATOR GRAPHICS AND CLINICAL APPLICATIONS 1

I. Basic Concepts, 1

II. Effect of Setting Changes on Waveforms, 2

III. Effect of Flow Rate on Inspiratory and Expiratory Time, 4

IV. Effect of Resistance and Compliance Changes, 6

V. Scalars, 8

VI. Modes of Ventilation and Corresponding Scalars, 10

Control Mode Ventilation, 10

Assist Mode Ventilation, 13

Sychronized Intermittent Mandatory Ventilation

(SIMV), 15

SIMV with Pressure Support Ventilation (PSV), 17

SIMV with PSV and Continuous Positive Airway Pressure

(CPAP), 19

Pressure Control Ventilation (PCV), 21

2. PRESSURE-VOLUME AND FLOW-VOLUME LOOPS 23

I. Total Lung Compliance, 23

II. Pressure-Volume Loops, 27

III. Work-of-Breathing, 32

IV. Flow-Volume Loops, 34

V. Interpretation of Loops, 36

3. WAVEFORMS FOR COMMON VENTILATOR MODES 53

I. Volume-Targeted Scalars, 55

Volume-Targeted Control Ventilation, 55

Volume-Targeted Assist Control Ventilation, 55

Volume-Targeted SIMV, 55

II. Pressure-Targeted Scalars, 57

Pressure-Targeted Control Ventilation, 57

Pressure-Targeted Assist Control Ventilation, 57

Pressure-Targeted SIMV, 57

III. Spontaneous Scalars, 59

Continuous Positive Airway Pressure (CPAP), 59

Pressure Support Ventilation (PSV), 59

PSV with CPAP, 59

Setting Rise Time for PSV, 60

Bilevel and APRV, 61

iii

table of contents rev.qxd 4/12/06 2:24 PM Page 1

IV. Combination Modes: Volume-Targeted Scalars, 63

Volume-Targeted SIMV with CPAP, 63

Volume-Targeted SIMV with PSV, 63

Volume-Targeted SIMV with PSV and CPAP, 63

V. Combination Modes: Pressure-Targeted Scalars, 65

Pressure-Targeted SIMV with CPAP, 65

Pressure-Targeted SIMV with PSV, 65

Pressure-Targeted SIMV with PSV and CPAP, 65

VI. Volume-Targeted Pressure-Volume (P-V) and

Flow-Volume (F-V) Loops, 67

Volume-Targeted Controlled Ventilation with a

Constant Flow, 67

Volume-Targeted Assisted Ventilation with a

Constant Flow, 67

Volume-Targeted SIMV, 67

VII. Pressure-Targeted P-V and F-V Loops, 69

Pressure-Targeted Controlled Ventilation, 69

Pressure-Targeted Assisted Ventilation, 69

Pressure-Targeted SIMV, 69

VIII. Spontaneous Ventilation P-V and F-V Loops, 71

CPAP, 71

PSV, 71

PSV with CPAP, 71

IX. Combination Modes: Volume-Targeted P-V and F-V Loops, 73

Volume-Targeted SIMV with CPAP, 73

Volume-Targeted SIMV with PSV, 73

Volume-Targeted SIMV with PSV and CPAP, 73

X. Combination Modes: Pressure-Targeted P-V and F-V Loops, 75

Pressure-Targeted SIMV with CPAP, 75

Pressure-Targeted SIMV with PSV, 75

Pressure-Targeted SIMV with PSV and CPAP, 75

4. MONITORING PRESSURE AND VOLUME VENTILATION 77

I. Volume vs. Pressure Ventilation Scalars, 78

II. Inspiratory Pause During Volume and Pressure Ventilation, 79

III. Effects on Increased Airways Resistance on Volume- and Pressure-

Targeted Ventilation, 81

IV. Effects of Decreased Compliance, 84

V. Three conditions for Pressure-Targeted Breaths, 85

VI. Descending Ramp Flow in Pressure Control, Pressure Supported,

and Volume-Targeted Breaths, 85

iv CONTENTS

table of contents rev.qxd 4/12/06 2:24 PM Page 2

5. COMMON CLINICAL FINDINGS 86

I. Changes in Respiratory System Compliance, 87

Decreased Compliance and Inflection Points, 87

Overdistension, 90

Active Exhalation, 91

II. Airway Obstruction, 92

Bronchospasm: Bronchodilator Benefit Assessment, 92

Air-trapping from Dynamic Hyperinflation, 94

Air-trapping from Early Small Airway Collapse, 96

Kinked Endotracheal Tube, 98

III. Patient-Ventilator Dyssynchrony, 99

Inadequate Inspiratory Flow Rate, 99

Inappropriate Trigger Sensitivity, 100

Patient and Ventilator Rates Out of Synchrony, 102

IV. Leaks, 103

6. NEONATAL APPLICATIONS 104

I. Introduction, 105

II. Normal Infant Pulmonary Functions, 106

III. Normal Scalars, Flow-Volume (F-V), and Pressure-Volume (P-V)

Loops, 107

IV. Abnormal Waveforms, 114

Improper Sensitivity Scalars, 114

Large Air Leak and Autocycling Scalars, 115

A/C Pressure Control Asychrony Scalars, 116

A/C Pressure Control F-V and P-V Loops, 117

Inadequate Flow Scalars, 118

Inadequate Rise Time or Flow, 118

Excessive Inspiratory Pressure and Flow Scalars, 119

Effect of Excessive Inspiratory Pressure on the

P-V Loop,119

Reduced Compliance F-V and P-V Loops, 120

Excessive Inspiratory Time Scalars, 121

Inspiratory Flow Termination Scalars, 122

Termination of Inspiratory Flow, 122

Breath-Stacking (Auto-PEEP) Scalars, 123

Breath-Stacking F-V and P-V Loops, 124

Obstruction to Expiratory Flow Scalars, 125

Obstruction to Expiratory F-V and P-V Loops, 126

Right Mainstem Intubation Scalars, 127

CONTENTS v

table of contents rev.qxd 4/12/06 2:24 PM Page 3

Right Mainstem Intubation F-V and P-V Loops, 128

Progression to Extubation Scalars, 129

Turbulent Baseline Flow Rate Scalars, 130

High Frequency Ventilation, 131

Appendix A: CASE STUDIES 134

Appendix A: VENT WAVEFORMS CHECKLIST 144

BIBLIOGRAPHY 145

INDEX 147