initiating positive pressure cmv a generic approach!
TRANSCRIPT
Initiating Positive Pressure CMV
A generic approach!
Do these BEFORE attaching the patient Assemble the ventilator circuit Attach humidifier and fill with water Attach high pressure O2 hose (may
also need hose for air) Plug ventilator in
Set the FIO2
If no prior ABGs, start on 100%
Set desired Vt
6-12 ml/kg
Set rate
Choose a rate that in conjunction with Vt, gives a minimum Ve of 6-8 LPM
ALWAYS THINK OF MINUTE VENTILATION WHEN SETTING RATE
Set flowrate
Start between 40-60 LPM Make sure it meets patients inspiratory
demand– Steady rise on manometer
Make sure it gives good I:E ratio The larger the Vt, the faster the
flowrate!
Set sigh parameters ( if using)
Sigh Vt = 1.5 x Vt Sigh rate = 6-10 per hour
Set sensitivity
If pressure triggering, set for 1-2 cmH2O pressure drop
If flow triggering, usually set for 3-5 LPM drop in flow
Turn ventilator on and attach patient
Note: make sure high pressure alarms are set at 50 cmH2O to start the patient on CMV
Set high pressure alarms
For Vt, set 5-10 cmH2O greater than peak pressure for Vt
For sigh, set 5-10 cmH2O greater than peak pressure for sigh
Set low exhaled volume alarm
Set 100 ml less than Vt
Set low pressure alarm
Set 5-10 cmH2O less than peak pressure for Vt
Alarms and Monitors
What they mean and what to do
Assist Light
Shows patient triggered the breath If patient is not triggering and light is on,
then ventilator is too sensitive– autocycling
Pressure Light
Shows ventilator pressure limited the breath
Also has audible alarm
Pressure limiting may be caused by: Secretions Water in the tubing Physical obstruction or a kink in tubing Change in patient position ET tube in right main stem bronchus Pneumothorax Maladjusted control
Indicates increased resistance
Also a decrease in compliance
Remember:
Flow =pressure/resistance
Ratio Light
Indicates inverse I:E – Inspiration is as long or longer than
expiration Increase flow!!!!!
Oxygen Lights
Red = FIO2 set to greater than 21% but not hooked up to source of O2– Usually has audible too
Green = FIO2 is greater than 21% Many ventilators only check for
pressure on the O2 line
Low exhaled Vt/Low pressure
Indicates a leak between ventilator and patient
The closer the leak is to the ventilator, the lower the manometer pressure
Low exhaled Vt/pressure causes:
Patient disconnect Leaking humidifier (very common) Leak in exhalation valve Loose nebulizer Loose tubing connection Leak in ET tube Alarm maladjustment
Tubing compliance
Tubing expands as it is pressurized Some of Vt from ventilator is lost to
tubing expansion Nondisposable circuit compliance is
about 3 ml/cmH2O
To figure out how much Vt is lost to tubing expansion: Multiply peak pressure by tubing
compliance (usually 3 ml/cmH2O) Subtract this number (tubing expansion
volume) from the set Vt The difference is known as effective or
corrected Vt Effective or corrected Vt is the Vt the
patient actually gets!
Flow sheet
Accumulated data Makes sure patient is being ventilated
effectively Allows trend analysis to aid in decisions
about ventilator management Filled out periodically, eg every 2 hours
Time to Rock and Roll!