initiating positive pressure cmv a generic approach!

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!