1. Recruitment, PEEP titration and Open Lung Tool®
LUNG RECRUITMENT
Recruitment,
PEEP titration
and
Open Lung Tool®
This presentation is focusing on one of many different methods to recruit a collapsed lung. This CT scan shows collapsed areas in the lower parts of the lungs. This is called atelectasis. This gives a shunt in the ventilation/perfusion (V/Q) because the blood that passes the collapsed alveoli will not pickup oxygen or release CO2. The Open Lung Tool® is a tool to help clinicians/users to evaluate the changes in the ventilatory settings when they are at the bedside. The Open Lung Tool® has focus on inspiratory dynamic compliance (Cdyni).
Atelectasis

2. Stepwise alternating PC level procedure
This stepwise method is one of many different ways to do lung recruitment. This method of recruitment consists of a stepwise increase of Pressure Control level above PEEP with intermittent periods of baseline ventilation. The intention with this method is to minimize negative hemodynamic influence. It should also allow for less stress and resting of lung tissue during unloaded periods of baseline ventilation. The risk of volutrauma could be increased if high pressure levels and prolonged time at high pressures are used. High Tidal volume and hypocapnia also occurs with this method. The stepwise procedure allows for a possibility to evaluate the response of Tidal volume (VTi), Elimination of Carbon Dioxide (VTCO2) and inspiratory dynamic compliance (Cdyni) to each change of ventilator setting. The size of pressure steps and duration of time at each setting have to be individually selected for each patient.
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3. Open Lung Tool Preparations Pressure Control Ventilation
6 ml/kg PBW (Predicted Body Weight)
I:E Ratio 1 to 1
Set Upper Pressure Limit Alarm
Stabile Hemodynamics
Sedation
Relaxation?
Have a maximum pressure target before starting the procedure
Press Quick Access/Open Lung Tool
Preparations.
Recruitment maneuver in Pressure Control Ventilation (PCV).
To give collapsed alveoli more time to open up set I:E Ratio 1 to 1.
Increase the Upper Pressure Limit Alarm (UPL) before starting the procedure, otherwise the maneuver will be cut of if the UPL is set lo low.
The patients’ hemodynamic status needs to be stabile. If it is not stable, the patients blood pressure can be affected and the procedure has to be aborted. A bolus of i.v. fluid and/or inotropic drugs might be needed.
The patient also needs to be sedated and/or maybe to be given muscle relaxants.
Have in mind a maximum target pressure for this procedure. Important to stop at the target, and evaluate the lung mechanics.
When the preparations is finished start the procedure by pressing Quick Access and Open Lung Tool®.
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4. Four different steps Recruitment Find the collapse point 3. Re-Recruit
Find the opening pressure
Find the collapse point
Decremental PEEP titration
3. Re-Recruit
Re-open the lung
4. Keep the lung open
Set “Open Lung PEEP”
A recruitment maneuver contains four steps.
Step one is to find the opening pressure (maximum End Inspiratory Pressure, EIP) for this specific lung at this specific time. One method is to use the Stepwise alternating PC level procedure.
Step two is to find at which PEEP the lung starts to collapse. To find the collapse PEEP, the lung must be opened up before starting the decremental PEEP titration. Start a decremental PEEP titration, reduce PEEP in steps of 1 cm/H20.
Step three is to re-recruit the lung because the lung is collapsed after step two.
Step four is the maintain the open lung ventilation. Ventilate with “Open Lung PEEP” . Open Lung PEEP is PEEP set 2 cm/H20 above collapsed PEEP.
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5. Step 1 – Find opening pressure
Start with normal tidal volume (baseline) (6 ml/kg).
First increase PEEP to (e.g.) cm/H20 in steps of 5 cm/H20, looking at the compliance curve when increasing PEEP.
Stepwise increase of Pressure Control level above PEEP with intermittent periods of baseline ventilation.
Increase Pressure Above PEEP stepwise in steps of (e.g.) 3 cm/H20 until a decrease in the VTCO2 curve, decrease in compliance curve or no more increase in FRC (baseline of tidal volume).
Finding the Opening Pressure.
Always have a target for the maximum EIP for this maneuver.
Start with normal “baseline” ventilation and a tidal volume approx. (6ml/kg Predicted Body Weight, PBW). Then increase PEEP in steps of (e.g. 5 cm/H20) above the closing PEEP. When increasing PEEP look at the compliance curve. Some lung areas will be opened up by increasing PEEP and therefore the compliance curve will increase. Continue the increase until the compliance curve don’t increase any more and then add another 5 cm/H20 of PEEP. That PEEP level should be above the collapse point. The PEEP level can be different for each patient but should be from e.g. 15 to 40 cm/H20. Adjust tidal volume to 6 ml/kg PBW.
Then increase Pressure Above PEEP stepwise in steps of e.g. 3 cm/H20. For each step when opening up closed compartments containing CO2, the VtC02 curve will increase. Stay for e.g. 5 to 10 breaths and go back to baseline. During this stepwise increasing of pressure the compliance curve will decrease. The evaluation of each step has to be done when ventilation is back to baseline. If more alveoli are opened, the compliance will increase and the baseline for volume will also increase due to increased FRC.
Continue to increase Pressure Above PEEP stepwise until a decrease in the VTCO2 curve or no more increase in FRC (baseline of tidal volume) or the pressure target is reached.
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6. Step 1 – Find opening pressure
1. volume (FRC)
2. CO2 elimination
3. compliance
Looking for opening pressure during recruitment
Look at the maximum baseline for tidal volume (blue curve). When no more alveoli are opened, there will be no more increase in the volume baseline (FRC). FRC is Functional Residual Capacity.
Look for the maximum elimination of CO2 (yellow curve). When applying high (to high) pressure in thorax the capillaries will be squeezed and therefore the CO2 elimination will no longer increase. VTC02 will decrease instead.
look for the maximum compliance (white curve). When increased pressure not will result in more opened alveoli the compliance will not increase any more.
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7. Step 2 – Find collapse PEEP
Back to baseline ventilation (normal tidal volume, 6 ml/kg)
Choose either Pressure Control or Volume Control Ventilation
Decrease PEEP in steps of 1 cm/H2O, if in VC the tidal volume is constant. If in PC try to keep the tidal volume by decreasing the Pressure above PEEP.
Continue until you get a decrease in the compliance curve.
Finding the collapse PEEP.
First adjust so there is the same tidal volume as in the baseline ventilation. This second part can also be done in Volume Control Ventilation (VCV) to maintain the tidal volume.
Decrease PEEP in steps of 1 cmH20 and look at the compliance curve. If this is done in PCV, try also to keep the tidal volume by decreasing the Pressure above PEEP. For each step down in PEEP, the compliance shall increase due to release of overdistention until the lung starts to collapse. If there is no increase of compliance during the first decrease of PEEP, the initial PEEP is set too low. Then start all over with higher initial PEEP.
Continue with the steps down until the compliance curve starts to drop. Be aware of that the tidal volume will be lower if PCV is used. In VCV the delta pressure (driving pressure for each tidal volume) will be lower for each step down until collapse starts, when the delta pressure will increase instead.
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8. Step 2 – Find collapse PEEP
Closing PEEP
Maximum compliance before lung starts to collapse.
During this step look only at the compliance curve (white curve). Look for the drop in the curve when lung starts to collapse. If there is a plateau in the compliance curve during several PEEP steps, choose the first (highest) PEEP value.
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9. Step 3 – Re-open the lung
Activate the OLT cursor and define the highest value of
VTCO2 elimination
Tidal volume baseline
Compliance
Look for the EIP at that point and memories.
(Compliance curve may lower first of these 3 curves above due to some overdistention).
Re-open the lung
The lung are now collapsed so it needs to be opened up again. As the targets for both maximum pressure and collapse PEEP now are identified, the rest of the procedure can be done more quickly.
If the mode is VCV, turn back to PCV.
Re-open the lung with the initial settings that were used during step 1 and 2. Start to set the initial PEEP. Then set EIP to the defined value. Stay long enough to open up the lung again. E.g. 1 to 2 minutes if hemodynamics are ok.
Then look for the maximum compliance by scrolling with the cursor again. Compare PEEP at the identified value. This PEEP is called closing PEEP.
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10. Step 3 – Re-open the lung 1. Initial PEEP 2. EIP (opening pressure)
Re-open the lung with initial PEEP and EIP defined during step 1. Stay for 1-2 minutes to give the lungs time to be re-opened. Look at the blood pressure.
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11. Step 4 – Keep the lung open
Back to normal tidal volume
Set Open Lung PEEP
Adjust to normal tidal volume
Set Upper Pressure Alarm to be clinically relevant
Keep the lung open
The Pressure Above PEEP should be lowered to baseline ventilation.
Then lower PEEP should be set at 2 cmH20 above the identified maximum compliance. This PEEP is called Open Lung PEEP. That’s to be sure to be on the “safe” side. Studies have shown that at maximum compliance, parts of the lung have already started to collapse.
Adjust to normal tidal volume. If more alveoli are opened up, the driving pressure (to give the same tidal volume as before recruitment) will be lower.
If necessary adjust the rate to have a acceptable CO2 level.
Remember to set back the Upper Pressure Limit Alarm to a clinically relevant level.
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12. Step 4 – Keep the lung open
compliance
before
after
1. Open Lung PEEP
2. Delta pressure
(driving pressure)
This screen dump shows open lung ventilation with Open Lung PEEP set to 16 cm/H20, 2 cm/H20 above collapsed PEEP. Driving pressure or delta pressure ( pressure to give tidal volume) of 4 cmH20. Compliance is increased compared to before the maneuver.
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13. Benefits with Stepwise Recruitment
Minimized negative hemodynamic influence
Allows for less stress and resting of lung tissue during periods of baseline ventilation
Possibility to evaluate the pulmonary response to each change of ventilator setting
Benefits with Sequential Recruitment
The intention with this method is to minimize negative hemodynamic influence.
It should also allow for less stress and resting of lung tissue during unloaded periods of baseline ventilation. The risk of volutrauma could be increased if high pressure levels and prolonged time at high pressures are used.
The stepwise procedure allows for a possibility to evaluate the response of VTi, VTCO2 and Cdyni to each change of ventilator setting.
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14. Result after a successful recruitment
Atelectasis
Increased compliance value
Lower mean airway pressure
Lower Delta-P (lower difference between EIP and PEEP)
Better oxygenation / PF-Ratio
No atelectasis
Result of a successful recruitment
The dynamic compliance will be higher (lung mechanics are improved) compared to before recruitment, due to more lung tissue (alveolus) involvement in the ventilation.
Dynamic compliance is a fraction of volume divided by pressure. After a successful recruitment mean airway pressure will be lower.
The driving pressure (delta pressure) for each tidal volume will be lower.
Better oxygenation / PF-Ratio that could led to lower Fi02 (set oxygen concentration) because of less shunt.
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15. References SERVO education – Study Guide SERVO-i ventilator system
Lung Recruitment, PEEP titration and Open Lung Tool
SERVO-i ventilator system
Operating Manual
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