NO ANSWER KEYS INCLUDED
WORKBOOK
, Contents
UNIT ONE BASIC CONCEPTS AND CORE KNOWLEDGE IN MECHANICAL VENTILATION
1. Basic Terms and Concepts of Mechanical Ventilation 1
2. How Ventilators Work 11
3. How a Breath Is Delivered 17
UNIT TWO INITIATING VENTILATION
4. Establishing the Need for Mechanical Ventilation 25
5. Selecting the Ventilator and the Mode 35
6. Initial Ventilator Settings 45
7. Final Considerations in Ventilator Setup 55
UNIT THREE MONITORING IN MECHANICAL VENTILATION
8. Initial Patient Assessment 65
9. Ventilator Graphics 75
10. Assessment of Respiratory Function 91
11. Hemodynamic Monitoring 103
UNIT FOUR THERAPEUTIC INTERVENTIONS-MAKING PPROPRIATE CHANGES
12. Methods to Improve Ventilation in Patient-Ventilator Management 115
13. Improving Oxygenation and Management of Acute Res iratory Distress Syndrome 125
UNIT FIVE EFFECTS AND COMPLICATIONS OF MECHANICAL VENTILATION
14. Ventilator-Associated Pneumonia 135
15. Sedatives, Analgesics, and Paralytics 141
16. Extrapulmonary Effects of Mechanical 1/'e tilation 149
17. Effects of Positive-Pressure Ventilation on the Pulmonary System 159
18. Problem Solving and Troubleshooting lill
UNIT SIX NONINVASIVE ROSITIYE-PRESSURE VENTILATION
19. Basic Concepts of Noninvasive:Pos·tive-Pressure Ventilation 183
UNIT SEVEN DISCONTINUATION FROM VENTILATION AND LONG-TERM VENTILATION
20. Weaning and Discontinuation from Mechanical Ventilation 193
21. Long-Term Ventilation 201
UNIT EIGHT NEONATAL AND PEDIATRIC RESPIRATION SUPPORT
22. Neonatal and Pediatric Mechanical Ventilation 209
UNIT NINE SPECIAL APPLICATIONS IN VENTILATORY SUPPORT
23. Special Techniques in Ventilatory Support 219
xi
Copyright© 2016 by Elsevier, Inc. All rights reserved. Contents
, UNIT ONE BASIC CONCEPTS AND CORE KNOWLEDGE
IN MECHANICAL VENTILATION
Basic Terms and Concepts
of Mechanical Ventilation
LEARNING OBJECTIVES
On completion of this chapter the reader will be able to 8. Calculate the airway resistance (Raw) given the peak
do the following: inspiratory pressure (PIP), a plateau pressure (P plateau),
1. Define ventilation, external respiration, and internal and the flow rate.
respiration. 9. From a figure showing abnormal compliance or
2. Draw a graph showing how intrapleural and alveolar airway resistance, be able to determine which lung
(intrapulmonary) pressures change during spontaneous unit will fill more quickly or with a greater volume.
ventilation and during a positive pressure breath. 10. Compare several time constants and explain how
3. Define the terms transpulmonary pressure, different time cons ants will affect volume distribution
transrespiratory pressure, transairway pressure, during inspira ion.
transthoracic pressure, elastance, compliance, and 11. Give the pe centage of passive filling (or emptying)
resistance. for one two three, and five time constants.
4. Provide the value for intra-alveolar (Pa1v) pressure 12. B iefly discuss the principle of operation of negative
throughout inspiration and expiration during normal, pressure, positive pressure, and high-frequency
quiet breathing. mechanical ventilators.
5. Write the formulas for calculating compliance and 13. Define peak inspiratory pressure, baseline pressure,
resistance. c:positive end-expiratory pressure (PEEP), and plateau
6. Explain how changes in lung compliance affect the pressure.
peak pressure measured during inspiration with a 14. Describe the measurement of plateau pressure.
mechanical ventilator. l
7. Describe how changes in airway condition canlead
to increased resistance.
1
Copyright© 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
,KEY TERMS CROSSWORD PUZZLE
1 2
3
4 5
6 7 8
9
10
11
12
13
14 15
16
17
18 19
Down
2 Pressure measured at the
mouth (three words)
3 Abbreviation for
20 21 ventilation using small
pulses of pressurized gas
at rates between 100 and
22 400 breaths/min
23 5 Complication of positive
pressure ventilation that
causes an inadvertent
buildup of positive pressure
24 in the alveoli (two words)
6 Abbreviation for ventilation
using lower than normal
25
tidal volumes and
respiratory rates between
60 and 100 breaths/min
Across 8 Pressure between the alveolus and the pleural
1 Alternate term for pressure in the airways of the space responsible for maintaining alveolar inflation
lungs (three words) (three words)
4 Total amount of gas remaining in the lungs after a 9 Another term for the highest pressure recorded at
resting expiration (three words) the end of inspiration (three words)
6 Abbreviation for a form of ventilatory support 11 Airway communications between the lung and
characterized by rates up to 4000 breaths/min pleural space (two words)
7 Pressure measurement when there is no gas flow 13 Highest pressure recorded at the end of inspiration
10 Pressure measured in the esophagus that is used to (three words)
represent intrapleural pressure (two words) 15 The ease with which the lungs distend
12 Movement of oxygen into cells and of carbon 16 Movement of oxygen into the bloodstream and
dioxide out of cells (two words) carbon dioxide out of the bloodstream (two words)
14 Measurement of elastic forces that oppose lung 17 Movement of air into the lungs for gas exchange
inflation (two words) and out of the lungs for carbon dioxide removal
18 Pressure in the airways of the lungs (two words) 18 Functional unit of the lung
19 Another term for intrinsic PEEP (hyphenated word) 20 Mathematical expression used to describe the filling
22 Impedance of gas flow through the conductive airways and emptying of lung units (two words)
24 Deliberate increase in the ventilator’s baseline 21 Tendency of the lungs to return to their original
pressure (two words) form after being stretched
25 Movement of gas molecules across a membrane 23 Difference between an area of high pressure and
low pressure
2
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
,CHAPTER REVIEW QUESTIONS b. Name at least three additional terms for pressure A.
1. Describe the difference between ventilation and 1.
respiration.
2.
3.
6. How is intrapleural pressure (Ppl) estimated?
2. The movement of oxygen and carbon dioxide in
and out of the alveolar capillaries is known as 7. The pressure gradient between airway pressure and
, whereas the movement of oxygen alveolar pressure is known as .
and carbon dioxide in and out of body tissues is called This pressure is responsible for the movement of air
. in the . This gradient is calculated
3. Describe the conditions necessary for air to flow from by the formula .
Point A to Point B in Figure 1-1.
8. The pressure needed to expand or contract both
the lungs and the chest wall at the same time is
Point Point
A B
. This pressure gradient is calculated
by the formula .
9. The pressure that is responsible for maintaining
alveolar inflation is known as and
4. The pressure in the potential space between the
is calculated by the formula .
parietal and visceral pleura is known as .
At the end of exhalation during spontaneous breathing 10. The pressure that is required for inflation of the lungs
and airways during positive pressure ventilation is
this pressure is approximately and
called and is calculated by the
at the end of inspiration is about .
formula .
11. Use Figure 1-2 to answer questions a through d.
a. What pressure gradient is represented by Point A
to Point C? What is its function during breathing?
A.
B.
b. What pressure gradient is represented by Point C
to Point D? What is its function during breathing?
C.
D. c. What pressure gradient is represented by Point D
to Point E? What is its function during breathing?
E.
5. Use Figure 1-2 for this question.
a. Identify the pressures labeled A through E.
3
Copyright © 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
, d. What pressure gradient is represented by Point B 17. Draw and label, on the graph in Figure 1-5, the
to Point D? What is its function during breathing? changes in intrapulmonary pressure that occur during
a positive pressure breath with a PIP of 45 cm
H2O, a Pplateau of 25 cm H2O, PEEP of 10 cm H2O,
inspiratory time of 1 second, and expiratory time of
2 seconds, followed by a spontaneous breath with the
12. On the graph in Figure 1-3, label the x- and y- axes, same baseline.
draw the changes in Palv during a spontaneous breath,
and label inspiration and expiration.
18. The highest pressure recorded at the end of inspiration
is called or
13. Describe how a negative pressure ventilator causes
air to move into an individual’s lungs. .
19. The pressure at which expiration ends is called
.
20. When end expiratory pressure is above atmospheric
pressure, this is called .
14. List three advantages of using negative pressure
ventilators. 21. The pressure required to overcome the elastic recoil
1. of the lungs is known as
and is measured on a mechanically ventilated person
2.
by .
3.
22. What are the two types of forces that oppose inflation
15. Calculate the transairway pressure (PTA) when the
mouth pressure (PM) is 125 cm H2O and the Palv is of the lungs?
15 cm H2O. and
23. The relative ease with which a structure distends is
16. Draw and label, on the graph in Figure 1-4, the known as , and the tendency of a
changes in intrapulmonary pressure that occur during structure to return to its original form after being
a positive pressure breath with a PIP of 30 cm H2O, a
Pplateau of 20 cm H2O, PEEP of 5 cm H2O, inspiratory stretched is known as .
time of 2 seconds, and expiratory time of 4 seconds.
24. Pulmonary compliance is defined as ,
and the formula is written as .
25. Normally, total compliance of the lungs and thorax
is about , but it can range from
to .
4
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
,26. While mechanically ventilated, the compliance value 38. How much pressure is needed to overcome airway
resistance when PIP is 30 cm H2O and Pplateau is 20 cm
for a male with normal lungs is and H2O?
for a female with normal lungs is .
27. What is the formula used to calculate static compliance? 39. What is the normal amount of pressure lost to airway
resistance when a patient has a properly sized
endotracheal tube?
28. When more pressure is required to deliver a set tidal
volume (VT), what is likely happening to compliance?
40. Calculate Raw for a ventilated patient with the
following: PIP 48 cm H2O, Pplateau 30 cm H2O, and a
29. Calculate the static compliance when Pplateau is 27 cm set flow rate of 40 L/min.
H2O, baseline pressure is 10 cm H2O, and VT is 750 mL.
30. Calculate the static compliance when Pplateau is 35 cm 41. Calculate airway resistance for a ventilated patient
H2O, baseline pressure is 5 cm H2O, and VT is 575 mL. with the following: PIP 25 cm H2O, Pplateau 15 cm
H2O, and a set flow rate of 60 L/min.
31. Calculate the static compliance when Pplateau is 18 cm
H2O, baseline pressure is 0 H2O, and VT is 650 mL. 42. Why are the characteristics of the lung not
homogenous?
32. What happens to PIP as the lungs become more
difficult to ventilate? What happens to lung compliance?
43. Compare the filling time and volume for a normal
lung unit, a low compliance unit, and a unit with high
33. Define resistance. airway resistance using the same driving pressure.
34. What is the formula for airway resistance (Raw)?
35. What is the normal resistance range for flow rates of
0.5 L/s?
44. What factors contribute to resistance when breathing?
36. What lung disease causes both airway resistance and
static compliance to increase?
45. What clinical factors can increase airway resistance
by decreasing the radius of the airways?
37. Calculate the PTA when PIP is 27 cm H2O and Pplateau
is 20 cm H2O.
5
Copyright © 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
,46. How many seconds will it take to allow 86% of the 53. Calculate the time constant for a mechanically
VT to be exhaled when compliance is 25 mL/cm H2O ventilated patient when the VT is 700 mL, PIP is
and resistance is 30 cm H2O/L/s? 45 cm H2O, Pplateau is 18 cm H2O, flow rate is
60 L/min, and PEEP is 5 cm H2O.
47. Calculate the time constant for a mechanically
ventilated patient when the VT is 600 mL, PIP is
30 cm H2O, Pplateau is 24 cm H2O, and flow rate is
60 L/min, with no PEEP.
54. Which of the two lung units represented in
Figure 1-6 will receive more volume given the
same amount of time for inspiration? Explain your
answer.
48. What percentage of passive filling occurs for 1, 2,
3, 4, and 5 time constants?
A B
49. The time constant for patient #1 is 0.05 second;
patient #2 is 3 seconds; and 0.5 second for patient #3.
If the same filling pressure is used for each, which
patient will receive the most volume during
inspiration and why?
55. Which of the two lung units represented in
Figure 1-7 will fill more quickly? Explain your
50. Calculate the time constant for a compliance answer.
of 55 mL/cm H2O and resistance of 6 cm
H2O/L/s.
51. What is the inspiratory time setting to allow
95% volume emptying for a patient with the time
constant calculated in Question 50?
A B
52. Why do patients with increased airway resistance
develop air trapping when ventilator rates are set too
high?
6
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
,CRITICAL THINKING QUESTIONS
1. When the PIP is 43 cm H2O and the Pplateau is 18 cm H2O, how much pressure is required to overcome the resistance
of the airways?
2. What time constants would you expect for a patient with Adult Respiratory Distress Syndrome?
3. Describe how emphysema causes lung units to have long time constants.
4. What time constants would you expect for a 30-week (gestational age) premature infant?
5. When measuring the Pplateau on a patient receiving mechanical ventilation you observe a Pplateau that is higher than the
PIP. What is one explanation for this?
CASE STUDIES
Case Study 1
A respiratory therapist reviews the following information concerning an intubated patient being mechanically
ventilated.
Time PIP Pplateau VT Set Flow Rate PEEP
0800 18 cm H2O 10 cm H2O 600 mL 45 L/min 5 cm H2O
1000 24 cm H2O 12 cm H2O 600 mL 45 L/min 5 cm H2O
1200 35 cm H2O 11 cm H2O 600 mL 45 L/min 5 cm H2O
1. What is the PTA at 0800, 1000, and 1200?
2. Calculate the Raw at 0800, 1200, and 1200.
7
Copyright © 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
, 3. Calculate the static compliance at 0800, 1000, and 1200.
4. Calculate one time constant at 0800, 1000, and 1200.
5. a. What caused the PIP to rise between 0800 and 1200?
b. What problems will this cause when ventilating the patient?
Case Study 2
The following information is obtained from the flow sheet of an intubated patient being mechanically ventilated.
Time PIP Pplateau VT Set Flow Rate PEEP
1000 40 cm H2O 28 cm H2O 550 mL 40 L/min 0 cm H2O
1200 47 cm H2O 37 cm H2O 550 mL 40 L/min 5 cm H2O
1400 54 cm H2O 43 cm H2O 550 mL 40 L/min 7 cm H2O
1600 45 cm H2O 33 cm H2O 450 mL 60 L/min 12 cm H2O
1. Complete the table below.
Time PTA Raw CSTAT Time Constant
1000
1200
1400
1600
2. What is the source of the rising PIP between 1000 and 1400?
3. What would be the minimum inspiratory time for this patient at 1600 hours?
8
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
WORKBOOK
, Contents
UNIT ONE BASIC CONCEPTS AND CORE KNOWLEDGE IN MECHANICAL VENTILATION
1. Basic Terms and Concepts of Mechanical Ventilation 1
2. How Ventilators Work 11
3. How a Breath Is Delivered 17
UNIT TWO INITIATING VENTILATION
4. Establishing the Need for Mechanical Ventilation 25
5. Selecting the Ventilator and the Mode 35
6. Initial Ventilator Settings 45
7. Final Considerations in Ventilator Setup 55
UNIT THREE MONITORING IN MECHANICAL VENTILATION
8. Initial Patient Assessment 65
9. Ventilator Graphics 75
10. Assessment of Respiratory Function 91
11. Hemodynamic Monitoring 103
UNIT FOUR THERAPEUTIC INTERVENTIONS-MAKING PPROPRIATE CHANGES
12. Methods to Improve Ventilation in Patient-Ventilator Management 115
13. Improving Oxygenation and Management of Acute Res iratory Distress Syndrome 125
UNIT FIVE EFFECTS AND COMPLICATIONS OF MECHANICAL VENTILATION
14. Ventilator-Associated Pneumonia 135
15. Sedatives, Analgesics, and Paralytics 141
16. Extrapulmonary Effects of Mechanical 1/'e tilation 149
17. Effects of Positive-Pressure Ventilation on the Pulmonary System 159
18. Problem Solving and Troubleshooting lill
UNIT SIX NONINVASIVE ROSITIYE-PRESSURE VENTILATION
19. Basic Concepts of Noninvasive:Pos·tive-Pressure Ventilation 183
UNIT SEVEN DISCONTINUATION FROM VENTILATION AND LONG-TERM VENTILATION
20. Weaning and Discontinuation from Mechanical Ventilation 193
21. Long-Term Ventilation 201
UNIT EIGHT NEONATAL AND PEDIATRIC RESPIRATION SUPPORT
22. Neonatal and Pediatric Mechanical Ventilation 209
UNIT NINE SPECIAL APPLICATIONS IN VENTILATORY SUPPORT
23. Special Techniques in Ventilatory Support 219
xi
Copyright© 2016 by Elsevier, Inc. All rights reserved. Contents
, UNIT ONE BASIC CONCEPTS AND CORE KNOWLEDGE
IN MECHANICAL VENTILATION
Basic Terms and Concepts
of Mechanical Ventilation
LEARNING OBJECTIVES
On completion of this chapter the reader will be able to 8. Calculate the airway resistance (Raw) given the peak
do the following: inspiratory pressure (PIP), a plateau pressure (P plateau),
1. Define ventilation, external respiration, and internal and the flow rate.
respiration. 9. From a figure showing abnormal compliance or
2. Draw a graph showing how intrapleural and alveolar airway resistance, be able to determine which lung
(intrapulmonary) pressures change during spontaneous unit will fill more quickly or with a greater volume.
ventilation and during a positive pressure breath. 10. Compare several time constants and explain how
3. Define the terms transpulmonary pressure, different time cons ants will affect volume distribution
transrespiratory pressure, transairway pressure, during inspira ion.
transthoracic pressure, elastance, compliance, and 11. Give the pe centage of passive filling (or emptying)
resistance. for one two three, and five time constants.
4. Provide the value for intra-alveolar (Pa1v) pressure 12. B iefly discuss the principle of operation of negative
throughout inspiration and expiration during normal, pressure, positive pressure, and high-frequency
quiet breathing. mechanical ventilators.
5. Write the formulas for calculating compliance and 13. Define peak inspiratory pressure, baseline pressure,
resistance. c:positive end-expiratory pressure (PEEP), and plateau
6. Explain how changes in lung compliance affect the pressure.
peak pressure measured during inspiration with a 14. Describe the measurement of plateau pressure.
mechanical ventilator. l
7. Describe how changes in airway condition canlead
to increased resistance.
1
Copyright© 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
,KEY TERMS CROSSWORD PUZZLE
1 2
3
4 5
6 7 8
9
10
11
12
13
14 15
16
17
18 19
Down
2 Pressure measured at the
mouth (three words)
3 Abbreviation for
20 21 ventilation using small
pulses of pressurized gas
at rates between 100 and
22 400 breaths/min
23 5 Complication of positive
pressure ventilation that
causes an inadvertent
buildup of positive pressure
24 in the alveoli (two words)
6 Abbreviation for ventilation
using lower than normal
25
tidal volumes and
respiratory rates between
60 and 100 breaths/min
Across 8 Pressure between the alveolus and the pleural
1 Alternate term for pressure in the airways of the space responsible for maintaining alveolar inflation
lungs (three words) (three words)
4 Total amount of gas remaining in the lungs after a 9 Another term for the highest pressure recorded at
resting expiration (three words) the end of inspiration (three words)
6 Abbreviation for a form of ventilatory support 11 Airway communications between the lung and
characterized by rates up to 4000 breaths/min pleural space (two words)
7 Pressure measurement when there is no gas flow 13 Highest pressure recorded at the end of inspiration
10 Pressure measured in the esophagus that is used to (three words)
represent intrapleural pressure (two words) 15 The ease with which the lungs distend
12 Movement of oxygen into cells and of carbon 16 Movement of oxygen into the bloodstream and
dioxide out of cells (two words) carbon dioxide out of the bloodstream (two words)
14 Measurement of elastic forces that oppose lung 17 Movement of air into the lungs for gas exchange
inflation (two words) and out of the lungs for carbon dioxide removal
18 Pressure in the airways of the lungs (two words) 18 Functional unit of the lung
19 Another term for intrinsic PEEP (hyphenated word) 20 Mathematical expression used to describe the filling
22 Impedance of gas flow through the conductive airways and emptying of lung units (two words)
24 Deliberate increase in the ventilator’s baseline 21 Tendency of the lungs to return to their original
pressure (two words) form after being stretched
25 Movement of gas molecules across a membrane 23 Difference between an area of high pressure and
low pressure
2
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
,CHAPTER REVIEW QUESTIONS b. Name at least three additional terms for pressure A.
1. Describe the difference between ventilation and 1.
respiration.
2.
3.
6. How is intrapleural pressure (Ppl) estimated?
2. The movement of oxygen and carbon dioxide in
and out of the alveolar capillaries is known as 7. The pressure gradient between airway pressure and
, whereas the movement of oxygen alveolar pressure is known as .
and carbon dioxide in and out of body tissues is called This pressure is responsible for the movement of air
. in the . This gradient is calculated
3. Describe the conditions necessary for air to flow from by the formula .
Point A to Point B in Figure 1-1.
8. The pressure needed to expand or contract both
the lungs and the chest wall at the same time is
Point Point
A B
. This pressure gradient is calculated
by the formula .
9. The pressure that is responsible for maintaining
alveolar inflation is known as and
4. The pressure in the potential space between the
is calculated by the formula .
parietal and visceral pleura is known as .
At the end of exhalation during spontaneous breathing 10. The pressure that is required for inflation of the lungs
and airways during positive pressure ventilation is
this pressure is approximately and
called and is calculated by the
at the end of inspiration is about .
formula .
11. Use Figure 1-2 to answer questions a through d.
a. What pressure gradient is represented by Point A
to Point C? What is its function during breathing?
A.
B.
b. What pressure gradient is represented by Point C
to Point D? What is its function during breathing?
C.
D. c. What pressure gradient is represented by Point D
to Point E? What is its function during breathing?
E.
5. Use Figure 1-2 for this question.
a. Identify the pressures labeled A through E.
3
Copyright © 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
, d. What pressure gradient is represented by Point B 17. Draw and label, on the graph in Figure 1-5, the
to Point D? What is its function during breathing? changes in intrapulmonary pressure that occur during
a positive pressure breath with a PIP of 45 cm
H2O, a Pplateau of 25 cm H2O, PEEP of 10 cm H2O,
inspiratory time of 1 second, and expiratory time of
2 seconds, followed by a spontaneous breath with the
12. On the graph in Figure 1-3, label the x- and y- axes, same baseline.
draw the changes in Palv during a spontaneous breath,
and label inspiration and expiration.
18. The highest pressure recorded at the end of inspiration
is called or
13. Describe how a negative pressure ventilator causes
air to move into an individual’s lungs. .
19. The pressure at which expiration ends is called
.
20. When end expiratory pressure is above atmospheric
pressure, this is called .
14. List three advantages of using negative pressure
ventilators. 21. The pressure required to overcome the elastic recoil
1. of the lungs is known as
and is measured on a mechanically ventilated person
2.
by .
3.
22. What are the two types of forces that oppose inflation
15. Calculate the transairway pressure (PTA) when the
mouth pressure (PM) is 125 cm H2O and the Palv is of the lungs?
15 cm H2O. and
23. The relative ease with which a structure distends is
16. Draw and label, on the graph in Figure 1-4, the known as , and the tendency of a
changes in intrapulmonary pressure that occur during structure to return to its original form after being
a positive pressure breath with a PIP of 30 cm H2O, a
Pplateau of 20 cm H2O, PEEP of 5 cm H2O, inspiratory stretched is known as .
time of 2 seconds, and expiratory time of 4 seconds.
24. Pulmonary compliance is defined as ,
and the formula is written as .
25. Normally, total compliance of the lungs and thorax
is about , but it can range from
to .
4
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
,26. While mechanically ventilated, the compliance value 38. How much pressure is needed to overcome airway
resistance when PIP is 30 cm H2O and Pplateau is 20 cm
for a male with normal lungs is and H2O?
for a female with normal lungs is .
27. What is the formula used to calculate static compliance? 39. What is the normal amount of pressure lost to airway
resistance when a patient has a properly sized
endotracheal tube?
28. When more pressure is required to deliver a set tidal
volume (VT), what is likely happening to compliance?
40. Calculate Raw for a ventilated patient with the
following: PIP 48 cm H2O, Pplateau 30 cm H2O, and a
29. Calculate the static compliance when Pplateau is 27 cm set flow rate of 40 L/min.
H2O, baseline pressure is 10 cm H2O, and VT is 750 mL.
30. Calculate the static compliance when Pplateau is 35 cm 41. Calculate airway resistance for a ventilated patient
H2O, baseline pressure is 5 cm H2O, and VT is 575 mL. with the following: PIP 25 cm H2O, Pplateau 15 cm
H2O, and a set flow rate of 60 L/min.
31. Calculate the static compliance when Pplateau is 18 cm
H2O, baseline pressure is 0 H2O, and VT is 650 mL. 42. Why are the characteristics of the lung not
homogenous?
32. What happens to PIP as the lungs become more
difficult to ventilate? What happens to lung compliance?
43. Compare the filling time and volume for a normal
lung unit, a low compliance unit, and a unit with high
33. Define resistance. airway resistance using the same driving pressure.
34. What is the formula for airway resistance (Raw)?
35. What is the normal resistance range for flow rates of
0.5 L/s?
44. What factors contribute to resistance when breathing?
36. What lung disease causes both airway resistance and
static compliance to increase?
45. What clinical factors can increase airway resistance
by decreasing the radius of the airways?
37. Calculate the PTA when PIP is 27 cm H2O and Pplateau
is 20 cm H2O.
5
Copyright © 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
,46. How many seconds will it take to allow 86% of the 53. Calculate the time constant for a mechanically
VT to be exhaled when compliance is 25 mL/cm H2O ventilated patient when the VT is 700 mL, PIP is
and resistance is 30 cm H2O/L/s? 45 cm H2O, Pplateau is 18 cm H2O, flow rate is
60 L/min, and PEEP is 5 cm H2O.
47. Calculate the time constant for a mechanically
ventilated patient when the VT is 600 mL, PIP is
30 cm H2O, Pplateau is 24 cm H2O, and flow rate is
60 L/min, with no PEEP.
54. Which of the two lung units represented in
Figure 1-6 will receive more volume given the
same amount of time for inspiration? Explain your
answer.
48. What percentage of passive filling occurs for 1, 2,
3, 4, and 5 time constants?
A B
49. The time constant for patient #1 is 0.05 second;
patient #2 is 3 seconds; and 0.5 second for patient #3.
If the same filling pressure is used for each, which
patient will receive the most volume during
inspiration and why?
55. Which of the two lung units represented in
Figure 1-7 will fill more quickly? Explain your
50. Calculate the time constant for a compliance answer.
of 55 mL/cm H2O and resistance of 6 cm
H2O/L/s.
51. What is the inspiratory time setting to allow
95% volume emptying for a patient with the time
constant calculated in Question 50?
A B
52. Why do patients with increased airway resistance
develop air trapping when ventilator rates are set too
high?
6
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
,CRITICAL THINKING QUESTIONS
1. When the PIP is 43 cm H2O and the Pplateau is 18 cm H2O, how much pressure is required to overcome the resistance
of the airways?
2. What time constants would you expect for a patient with Adult Respiratory Distress Syndrome?
3. Describe how emphysema causes lung units to have long time constants.
4. What time constants would you expect for a 30-week (gestational age) premature infant?
5. When measuring the Pplateau on a patient receiving mechanical ventilation you observe a Pplateau that is higher than the
PIP. What is one explanation for this?
CASE STUDIES
Case Study 1
A respiratory therapist reviews the following information concerning an intubated patient being mechanically
ventilated.
Time PIP Pplateau VT Set Flow Rate PEEP
0800 18 cm H2O 10 cm H2O 600 mL 45 L/min 5 cm H2O
1000 24 cm H2O 12 cm H2O 600 mL 45 L/min 5 cm H2O
1200 35 cm H2O 11 cm H2O 600 mL 45 L/min 5 cm H2O
1. What is the PTA at 0800, 1000, and 1200?
2. Calculate the Raw at 0800, 1200, and 1200.
7
Copyright © 2016 by Elsevier, Inc. All rights reserved. Chapter 1 Basic Terms and Concepts of Mechanical Ventilation
, 3. Calculate the static compliance at 0800, 1000, and 1200.
4. Calculate one time constant at 0800, 1000, and 1200.
5. a. What caused the PIP to rise between 0800 and 1200?
b. What problems will this cause when ventilating the patient?
Case Study 2
The following information is obtained from the flow sheet of an intubated patient being mechanically ventilated.
Time PIP Pplateau VT Set Flow Rate PEEP
1000 40 cm H2O 28 cm H2O 550 mL 40 L/min 0 cm H2O
1200 47 cm H2O 37 cm H2O 550 mL 40 L/min 5 cm H2O
1400 54 cm H2O 43 cm H2O 550 mL 40 L/min 7 cm H2O
1600 45 cm H2O 33 cm H2O 450 mL 60 L/min 12 cm H2O
1. Complete the table below.
Time PTA Raw CSTAT Time Constant
1000
1200
1400
1600
2. What is the source of the rising PIP between 1000 and 1400?
3. What would be the minimum inspiratory time for this patient at 1600 hours?
8
Chapter 1 Basic Terms and Concepts of Mechanical Ventilation Copyright © 2016 by Elsevier, Inc. All rights reserved.
