The goal is to deliver an IPV treatment with decreased risk of de-recruitment, by having a guaranteed peep
Set-up
Run IPV in-line with Bi-Level/APRV and not pressure control because Bi-level allows the additional flow from the ipv, that the ventilator isn’t accounting for, to pass through the expiratory valve. This reduces the possibility of the high pressure spikes dumping the breath
Starting points for Phigh (PIP) and Plow (Peep)
2-3 below the current PIP and current peep, then adjusted for patient need
Do not just match current Vent settings because
With the added ipv flow the pip and peep will be higher than the set values
The set values are guaranteed minimums
After placement, look at waveform pulses for actual peep set value
If the bottom peep pulse only falls to 10 cmh20 with a peep of 0 set, that’s at least a peep of 10 and at set peep of 10 on the servo isn’t necessary
Usage
Percussion effects on PCO2 and SpO2 are inversed
The slower the frequency (pulse frequency), the larger the volume and less peep is trapped. This blows off CO2 and drops SpO2 because the ratio of i:e is fixed. Slowing the rate down makes the inspiratory time of the pulse, longer, which allows for a higher pressure to be reached during the inspiratory burst. It also makes the E time longer thus allowing more time for air to escape. This makes for a higher inspiratory volume and less % of it trapped
The faster rates improve SpO2 and increases CO2, because the faster rates shorten the inspiratory time and thus limits the pressure reached during the inspiratory phase of the burst. Also, the E time is short and traps air faster, driving up the peep with each burst. So faster rates lead to smaller inspiratory volumes with a higher % of it trapped
A change in CVP during your treatment
Indicates an increase in intrathoracic pressure
Please take note of the CVP before starting and have RN stop running fluid boluses as need for accurate reading during treatments
If chest wiggle is diminished
Not enough inspiratory pressure
Too much FRC, so turn the set peep down.
I to E ratio
Generally, 1:1, however can adjust based on patient need. If need more time for secretion clearance stretch out E time to a 1:2 or 1:3 as long as oxygenation status is not compromised
You made need more time to exhale based on CO2 and the patient or more oxygenation
The higher the resistance there is to expiratory flow, the lower the flow will be and there will be less secretion movement. During the time high in your treatment, more requirement is obtained while limiting the secretion movement ability. During the lower phase you will get more secretion movement and less lung recruitment. This is why a 1:1 is typically chosen, however a 1: 2 or 1:3 could be used on pt’s that secretion mobilization is paramount to lung recruitment
4 Points on the Waveforms
Look to see where the four pulse points hit on the pressure waveform, top and bottom of the inspiratory phase and top and bottom of the peep phase
The four points represent the absolute lowest and highest pressures any lung tissue could possibly see. However, it is unrealistic to believe that these maximums are ever reached at the rates and inspiratory times used during the pulses so an average of the two in each phase is guesstimated
The patient pressure is somewhere between the four pulse points on the servo waveform screen. Actual delivered lung pressure and volume is unmeasurable at such high rates, much like with the HFOV, chest rise and wiggle must be used as guides to adjust settings