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Guest jammaltaleb

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  • 2 weeks later...
Guest Dr. Petrov

Hi! What type of ventilator are you use for this regime? We have the PSV protocol for Viasys VIP Bird. It may be different for other machine

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  • 3 months later...
Guest Dr. Petrov

Hi, mr. Manojpotdar. Excuse me for severe delay with answer. I spent all summer far away from civilization. So, here it is. Please, don`t hesitate to ask me questions.

Protocol of newborn`s managing during mechanical ventilation with pressure support (IMV + PSV).

Patient-triggered ventilation with pressure support gain some advantantages over conventional ventilation. This regime may be used successfully for the most of patients.


- weaning from mechanical ventilation*

* actually now we use this regime in acute phase too in case of stable patient


- absens of spontaniouse breathing attempts

- acute stage of RDS with unstable hymodynamics

- congenital heart disease with abnormal circulation

Small age of gestation and low birth weight are not contraindications for IMV + PSV!

Preparation before starting IMV + PSV

1. Blood gases and X-Ray

2. Exclude gas leakage beside endotracheal tube. If leakage is more than 1/3 of minute volume of ventilation it need to reintubate patient with larger tube.

3. Set alarm limits:

- breathing rate not more than 100 / min

- minimal tidal volume 4-6 ml/kg

Initial parameters settings:

1. Assist Sensitivity - 0.2. If breathing rate more then 100/min we increase sensitivity up to 1.0

2. Pressure Support (PS): initial level PS = PIP – PEEP, but not less then 6 - 8 cmH2O*.

*For example, if during conventional ventilation Pin was 18 and PEEP was 4, the PS will set 14 cm H2O.

3. Inspiratory Time: 0.3 sec if body weight < 1500 g; 0.35-0.38 сек if BW more than 1500 g.

4. Flow: 6 l/min for preterm babies and 8 l/min for term babies. If alarm «Demand» (lack of flow) is active, it need to increase flow rate in 1-2 l/min

5. Rise Time: 5

6. Termination Sensitivity: 15%

Regulation of settings

Changes in settings are depend on clinical status, blood gases and respiratory function. We perform blood gases analysis in 30 minutes after starting IMV+PSV and then every 6 hours.


• РаСО2 < 30 mm Hg - it is required to increase assist sensitivity by 0.2

• РаСО2 30- 35 mm Hg - it is required to increase assist sensitivity by 0.1

• РаСО2 35-50 mm Hg – no need in changes

• РаСО2 > 50 mm Hg – it is required to increase ventilation rate by 5/min, repeat blood gases in 30 minutes

NB! For patients with CLD (BPD) РаСО2 50-60 mm Hg is normal.


• РаО2 < 50 mm Hg – it is required to increase РЕЕР by 2 см Н2О; repeat blood gases in 30 minutes. If it is nesessary you may increase FiO2 by 10%

• РаО2 > 60 mm Hg – it is required to diminish FiO2 by 10%

МАР (mean airway pressure)

• МАР > 9-10 cm Н2О – it is required to diminish pressure support by 2 cmH2O

• МАР 6-8 см Н2О – no need in changes

• МАР < 6 см Н2О – it is required to decide about stopping ventilation and extubation

Ventilation rate / tidal volume ratio (VR/Vt):

If breathing rate is increasing but tidal volume is diminishing it is sign of worsening of respiratory function. In this case you have to:

• increase set ventilator rate by 10/min

• increase pressure support by 2 cm H2O

• Repeat blood gases in 30 minutes.

Common problems:

1. total breathing rate more than 70/min.

• Exclude auto-triggering due to condensated water in breathing contour

• Eliminate stressfull factors (pain, hypothermia, hunger)

• Assess VR/Vt ratio:

o If ratio is diminishing it is required to increase assist sensitivity

o If ratio is rising it is required to increase set ventilator rate by 10/min or increase pressure support by 2 cm H2O. Exclude athelectasys or pulmonary edema.

2. Expiratory resistance more than > 600 cm/l/sec

• Main reason of this cases is tube obstruction by sputum. Perform tube suctioning

• Assess depth of tube insertion and exclude single-lung ventilation

• Exclude pulmonary edema

3. Inexplicable worsening of situation

• Turn back to conventional ventilation

• Call to head doctor for consultation

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