1. CMV Mode Workshop

2. Objectives:
Know the difference between controlled ventilation and assist/control
Controlled variables: PC-CMV vs VC-CMV
Phase variables: trigger/limit/cycle
Know the breath types
Know the breath sequence
Settings and adjustment
Indications, advantages and disadvantages

3. Continuous Mandatory Ventilation
All breaths are mandatory and can be volume or pressure targeted
Controlled Ventilation – when mandatory breaths are time triggered
Assist/Control Ventilation – when mandatory breaths are either time triggered or patient triggered

4. Mandatory Modes of Ventilation CMV
Control
Trigger
Limit
Target
Cycle
Pressure Or
Volume
Time
Pressure or Volume
Time or Volume
Time Triggered Time Cycled Ventilation

5. Controlled Ventilation: Breath Types
All breaths are mandatory breaths
Ventilator determines the start time (time triggered)
Ventilator delivers the set control (volume or pressure target)
Te ventilator ends the breath (time- or volume-cycled)

6. Controlled Ventilation: Breath Sequence
All breaths are mandatory breaths

7. Controlled Ventilation: Indications
Appropriate when a patient can make no effort to breathe or when ventilation must be completely controlled
Drugs
Cerebral malfunctions
Spinal cord injury
Phrenic nerve injury
Motor nerve paralysis

8. Controlled Ventilation: Indications
In other types of patients, controlled ventilation is difficult to use unless the patient is sedated or paralyzed with medications
Seizure activity
Tetanic contractions
Inverses I:E ratio ventilation
Patient is fighting (bucking) the ventilator
Crushed chest injury – stabilizes the chest
Complete rest for the patient

9. Controlled Ventilation: Settings
Adequate alarms must be set to safeguard the patient
E.g., disconnection
Sensitivity should be set so that when the patient begins to respond, they can receive gas flow from the patient
Do not lock the patient out of the ventilator!

10. Control Mode (Pressure-Targeted Ventilation)
Set PC Level
Time Cycling
Pressure
(cm H2O)
Flow
(L/m)
Volume
(mL)
Time (sec)
Time Triggered, Pressure Limited, Time Cycled Ventilation

11. Control Mode (Volume-Targeted Ventilation)
Time Cycling
Pressure
(cm H2O)
Dependent on
CL & Raw
Flow
(L/m)
Preset VT
Volume Cycling
Volume
(mL)
Time (sec)
Time Triggered, Flow Limited, Volume Cycled Ventilation

12. Pressure Or Volume-Targeted Ventilation
Advantages
Disadvantages
Decreases the work of breathing (WOB)
Helps maintain a normal PaCO2
Not able to assist the ventilator

13. Hybrid Modes of Ventilation A/C
Control
Trigger
Limit
Target
Cycle
Pressure Or
Volume
Time
Patient
Pressure or Volume
Time or Volume
Time or PatientTriggered Time Cycled Ventilation

14. Assist/Control Ventilation
A time or patient triggered CMV mode in which the operator sets a minimum rate, sensitivity level, type of breath (volume or pressure)
The patient can trigger breaths at a faster rate than the set minimum, but only the set volume or pressure is delivered with each breath

15. Volume Controlled-CMV
Time or patient triggered, volume targeted, volume cycled ventilation
Graphic (VC-CMV)
Time-triggered, constant flow, volume-targeted ventilation

16. Volume Controlled-CMV
Time or patient triggered, volume targeted, volume cycled ventilation
Graphic (VC-CMV)
Time-triggered, descending-flow, volume-targeted ventilation

17. Pressure Controlled-CMV
PC – CMV (AKA – Pressure control ventilation - PCV)
Time or patient triggered, pressure targeted (limited), time cycled ventilation
The operator set the length of inspiration (Ti), the pressure level, and the backup rate of ventilation
VT is based on the compliance and resistance of the patient’s lungs, patient effort, and the set pressure

18. Pressure Controlled-CMV
Airway pressure is limited, which may help guard against barotrauma or volume-associated lung injury
Maximum inspiratory pressure set at 30 – 35 cm H2O
Especially helpful in patients with ALI and ARDS
Allows application of extended inspiratory time, which may benefit patients with severe oxygenation problems
Usually reserved for patient who have poor results with a conventional ventilation strategy of volume ventilation

19. Assisted Mode (Volume-Targeted Ventilation)
Time Cycling
Pressure
(cm H2O)
Preset peak Flow
Flow
(L/m)
Volume
(mL)
Time (sec)
Patient Triggered, Flow limited, Volume Cycled Ventilation

20. Assisted Mode (Pressure-Targeted Ventilation)
Set PC Level
Time Cycling
Pressure
(cm H2O)
Flow
(L/m)
Volume
(mL)
Time (sec)
Patient Triggered, Pressure Limited, Time Cycled Ventilation

21. Assist/Control Ventilation
Indications
Patients requiring full ventilatory support
Patients with stable respiratory drive
Advantages
Decreases the work of breathing (WOB)
Allows patients to regulate respiratory rate
Helps maintain a normal PaCO2
Complications
Alveolar hyperventilation

22. Thank You