1. Mechanical Ventilation

2. Behavioral Objectives The participant will be able to:
1. Write complete ventilator orders for modalities of CMV.
2. Identify and describe modes of ventilation; CMV,
(volume, pressure), SIMV, pressure support, NIPPV,
CPAP, BIPAP.
3. Identify types of ventilator graphics; (scalars, loops).
4. Determine air trapping, autopeep, air leak,
ventilator asynchrony.
5. Describe and recognize modes for protective lung strategies

3. Ventilator Orders: CMV Volume Ventilation:
A/C, rate 12, Vt 500, PEEP 5, titrate Fi02 to keep Sp02 > 94%
CMV Pressure Control:
rate 18, PIP 30, PEEP 15,
Itime 1.5, I:E (1:1, 1:2, 2:1, 3:1, 4:1), Fi02 same as above.
SIMV Volume Ventilation:
SIMV, rate 8, Vt 500, pressure
support 5, PEEP 5, Fi02 same as above.
SIMV Pressure Control Ventilation:
PIP 30, rate12, Itime 1.0, PEEP 5, pressure support 5,

4. Ventilator Orders: Spontaneous Ventilation: Pressure support 5, PEEP 5
CPAP 5
BIPAP 15/5-non invasive ventilation mask, nasal mask.
Protective Lung Modes:
ARDSnet protocol
Bilevel/APRV, THigh 4-6 sec., Tlow
sec., PHigh 20-35cmH20, PLow 0, optional pressure support.
3. Oscillator Hz 4-15, MAP 30,
amplitude (determined by chest
wiggle).

7. VENTILATOR GRAPHICS

8. Objectives A. General 1. Identify the two basic graphic waveforms
2. Identify the three scalars
3. Identify the two loops
B. Identify on a flow vs. time scalar
1. Airway obstruction vs. active exhalation
2. Response to bronchodialators
3. Air trapping or auto-PEEP
C. Identify on a volume vs. time scalar
1. Presence of an air leak
2. Active exhalation
D. Identify on a pressure vs. time scalar
1. Peak pressures and plateau pressures
2. Inadequate flow
E. Identify on a pressure-volume loop
1. PEEP and inflection points
2. Work of breathing
3. Decreased lung compliance
4. Increased airway resistance
5. Alveolar overdistension
6. Inadequate sensitivity
7. Inadequate inspiratory flow
8. Air leak
F. Identify on a flow-volume loop
1. Auto-PEEP
2. Air leak
3. Increased airway resistance
4. Airway secretions/water in the circuit
G. Recognize through waveforms
1. Spontaneous modes
2. Pressure support ventilation
3. Volume targeted ventilation
4. Pressure targeted ventilation

9. Ventilator graphics have become an essential tool in the management of mechanically ventilated patients. These graphics are displayed in two basic forms - - scalars and loops.
A. Scalars
- Any single variable displayed against time
* Flow curve
* Pressure curve
* Volume curve
B. Loops
- A two-dimensional graphic display of two scalar
values.
* Pressure-volume loop
* Flow-volume loop

11. CPAP mode is identical to a spontaneous breath except that the baseline is at a higher level on the pressure vs. time time curve
B. Pressure Support Ventilation
The key waveform for identifying PSV is the flow vs. time curve. Inspiration terminates when the flow reaches a predetermined value (25% of peak flow), and volume can vary.

12. C. Volume-Targeted Ventilation
In assist control mode notice the negative deflection just prior to the initiation of the mechanical breath, indicating patient triggering.
Notice the difference in volumes between the intermittent mechanical breaths where the volume is pre-set and the pressure supported spontaneous breaths where the volume can vary.

13. D. Pressure-Targeted Ventilation
Notice the negative deflection just prior to the mechanical breaths indicating patient triggering.
Notice the difference in volumes between the mechanical breaths where volume is pre-set and the spontaneous breaths where volume can vary. Also notice the
negative deflection indicating patient effort.

14. Recognition of Common Abnormalities Flow vs. Time Scalars
A. Airway Obstruction vs. Active Exhalation
* Exhalation is normally passive
* The expiratory flow pattern and PEFR depend
upon changes in compliance, resistance, and
active efforts to exhale

15. Increased airway resistance due to bronchospasm or accumulation of secretions in the airway may result in decreased PEFR and a prolonged expiratory flow. If the patient begins to actively exhale using expiratory muscles, it may result in an increase in PEFR and a shorter duration of expiratory flow.
B. Response to Bronchodialator
* Can verify clinically suspected bronchoconstriction
* PEFR reduced and expiratory flow returns to
baseline very slowly
C. Air Trapping or Auto-Peep
* An event in which expiratory flow does not
return to the zero line and the subsequent
inspiration begins below the baseline

16. The presence of auto-PEEP or airtrapping can result from an inadequate expiratory time, too high of a respiratory rate, too long of an inspiratory time, and a prolonged exhalation due to bronchoconstriction.
Volume vs. Time Scalars
A. Presence of an Air Leak
* Can be detected if an expiratory tracing
smoothly descends, then plateaus, but does
not reach baseline

17. The volume of the leak can be easily estimated by measuring the distance from the plateau to the end of the expiratory tracing.
B. Active Exhalation
* Seen on a volume-time tracing as extending
below the zero line
This tracing can also occur if the flow transducer is out of calibration.
Pressure vs. Time Scalar
A. Peak Inspiratory Pressure vs. Plateau Pressure
- There are four curves that have profound
clinical significance
* Normal curve
* High airway resistance
* High flow
* Decreased lung compliance

18. B. Inadequate Flow
* Indicated when the pressure rises very slowly
This tracing can also occur when there is a depression in the inspiratory limb of the pressure contour.

19. Pressure-Volume Loop
A. PEEP and Inflection Points
When PEEP is applied, the pressure-volume curve shifts to the PEEP level on the horizontal scale.

20. Inflection points represent sudden changes in alveolar opening and closing. The lower inflection point represents the opening pressure, where as the upper inflection point
represents recoiling characteristics. Setting PEEP at the level of the lower inflection point is reccomended, to optimize alveolar recruitment and prevent repeated opening and closing of the alveoli.
B. Work of Breathing
* Provides a quick assessment of the elastic as
well as resistive work of breathing
Work of breathing = Pressure X Volume

21. C. Decreased Lung Compliance
A shift of the curve to the right of a pressure-volume loop indicates decreased lung compliance. A shift to the left is associated with an increase in compliance.
Volume Targeted Ventilation
In volume targeted ventilation the PIP is the changing variable. In pressure targeted ventilation PIP is the constant and VT is the changing variable.
Pressure Targeted Ventilation

22. D. Increased Airway Resistance
An abnormal widening of the inspiratory tracing indicates increased airway resistance. Patients with obstructive disorders usually exhibit this type of pressure-volume loop. This
abnormal widening of the inspiratory side is referred to as an increased hystersis.
E. Alveolar Overdistension
This is a common observation during ventilation of patients with ARDS. The classic sign known as “beak effect” or “duckbill” correlates with an increase in airway pressure without
any appreciable increase in volume.

23. F. Inadequate Sensitivity
The pressure-volume loop normally traces in a counterclockwise direction. If a clockwise tracing is present prior to the initiation of a mechanical breath, this indicates patient effort. Adjusting the
sensitivity can minimize or eleviate this effort. If the sensitivity is not adjusted it creates an increased work of breathing for the patient.
G. Inadequate Inspiratory Flow
A scooped out pattern indicates inadequate inspiratory flow rates. You may also see a notch on the inspiratory curve indicating a patient effort in the middle of the breath .

24. H. Air Leak
An air leak is present when the expiratory curve does not return to zero volume
Flow-Volume Loop
A. Auto-PEEP
In an air trapping situation the flow does not return to zero level. Since the next breath must begin from zero, the tracing jumps abruptly from the trapped level to zero and proceeds with the next breath.

25. C. Increased Airway Resistance
B. Air Leak
Expired volume is less than inspired volume when an air leak is present, and the volume does not return to zero on a flow volume loop. This is a common tracing when there is a leak around the ET tube or in the circuit.
C. Increased Airway Resistance
Increased airway resistance (due to bronchospasm) shows as a scooped out pattern on the expiratory tracing of a flow volume loop. Administration of a bronchodialator should show on the tracing, however if it does not improve it indicates the ineffectiveness of the bronchodialator therapy.

26. Recognizing Modes of Ventilation Through Waveforms
D. Airway Secretions/Water in the Circuit
The presence of secretions in the large airways, as well as excess fluid in the ventilator circuit, will appear as a “saw-tooth” pattern on a flow-volume loop. This
will most often appear on the expiratory component of the loop but if the situation is not corrected it can also appear on the inspiratory component.
Recognizing Modes of Ventilation Through Waveforms
A. Spontaneous Modes
Notice only the pressure curve shows a negative or below baseline tracing during inspiration. Flow and Volume are both positive during inspiration.

27. Post Test 1. What are the two basic graphic forms?
2. How can you tell if a bronchodialator was effective on a flow vs. time scalar?
3. How can you tell if a patient is air trapping on a flow vs. time scalar?
4. How can you tell if there is an air leak and the volume of the air leak on a flow vs. time scalar?
5. How can you tell if a patients flow rate is inadequate on a pressure vs. time scalar?
6. How can you tell if there is PEEP on a pressure-volume loop?
7. What do the upper and lower inflection points represent?
8. How does setting PEEP at the lower inflection point help to prevent atelectatic injury?

28. 9. What does a shift of the curve indicate on a pressure-volume loop in: a) volume targeted ventilation b) pressure targeted ventilation?
10. Patients with COPD usually have what changes on a pressure-volume loop and what is indicated by this change?
11. What does the “duckbill” represent on a pressure-volume loop in an ARDS patient?
12. How can you tell if a patient has an increased work of breathing on a pressure-volume loop?
13. What does a scooped out pattern indicate on a pressure-volume loop?
14. What does it mean when the expiratory part of the curve does not return to zero on a pressure-volume loop?
15. How can you tell if a patient is air trapping on a flow-volume loop?
16. What does it mean when expired volume is less than inspired volume on a flow-volume loop?

29. 17. What indicates an increased airway resistance due to bronchospasm on a flow-volume loop?
18. If there is water in the circuit or excess secretions in the large airways how will the flow-volume curve look?