1. Mechanical Ventilation of the Pre-term and Term Neonates
Roles of the Respiratory Therapist and the Nurses

2. Mechanical Ventilation Settings and Terms
Modes of Ventilation:
PC or PCV=Pressure Control Ventilation
VC/AC= Volume Control or Assist Control Ventilation
PS=Pressure Support setting on ventilator, cmH2O
VG=Volume Guarantee
TPS= Total Pressure Support: PS setting + PEEP setting, cmH2O
PIP=Peak Inspiratory Pressure (Actual PC setting + PEEP), cmH2O
PEEP=Positive End Expiratory Pressure, cmH2O
RR=Respiratory Rate, bpm
IT= Inspiratory Time, s or secs
FiO2= Oxygen percentage delivered, %
Slope: speed of flow delivery of gas
*Alarms are to be set within Respiratory Care Nursery guidelines, TBD

3. Olathe Medical Center’s Goal for babies on CPAP or mechanical ventilation:
- Neonates must be 34 weeks gestational age or greater
- Be able to be extubated within 24 hours, limited to less than 24hours of assisted mechanical ventilation
Will be limited to CPAP(Infant Flow System) or can be ventilated(Drager XL) adequately in the following modes: PCV+, PC-VG and PS-VG

4. Ventilation Modes on the Drager XL that will be most often used here at Olathe Medical Center’s NICU
Pressure Control Plus (PCV+)
Pressure Control Volume Guarantee (PCV-VG)
Pressure Support with Volume Guarantee (PS-VG)

5. Pressure Control Plus (PCV+)
PCV+ is mode of ventilation where each breath is delivered at a set pressure(not volume); subsequently, tidal volumes vary depending on lung compliance and resistance.
In PCV+, the patient always receives the set respiratory rate(RR) and if the patient triggers additional breaths, the ventilator will respond with a pressure assisted/supported(PS) breath.
Initial inspiratory flow is fast moving to slower as we approach the set pressure, so we call this a decelerating flow waveform and a square pressure waveform.
The settings required in this ventilation mode are:
- PIP which is a combination of PC + PEEP
- PEEP-Positive End Expiratory Pressure
- FiO2
- RR- Respiratory Rate
- Flow Trigger- the minimum amount of inspiratory flow required by the patient to trigger a breath whether it be a mandatory breath or a spontaneous breath
- Total Pressure Support(TPS) which is a combination of Pressure Support + PEEP
- Slope- A dial that determines how quickly a targeted pressure is delivered

6. PCV+ Waveform Graph 2 1

7. Advantages to PCV+ mode
Every breath is fully supported by the ventilator
PCV+ mode acts in an assist-control mode with a minimum set rate and all triggered breaths above that rate are also fully supported
In PCV+, the set respiratory rate that is given to the patient is delivered at a constant inspiratory pressure with a decelerating variable inspiratory flow rate
-inspiratory pressure is limited/more stable

8. Disadvantages of PCV+
Changes in lung compliance or resistance will result in variable tidal volumes
As lung compliance decreases(i.e. stiffer lungs) or airway resistance increases(↑Raw) tidal volumes will decrease which can lead to increased PCO2(hypercarbia), acidosis
As lung compliance increases or airway resistance decreases(↓Raw), tidal volumes will increase which can lead to hypocarbia, volutrauma

9. Pressure Control Volume Guarantee PC-VG
PC-VG is a mode of ventilation in which all breaths whether initiated by the ventilator or the patient are volume guaranteed pressure supported breaths. The ventilator delivers the tidal volume at the lowest pressure compensating for changes in the patients lung compliance. The ideal pre-term infant this mode of ventilation would be used on are the infants may already have chronic lung disease, Meconium Aspiration Syndrome and any other situations in which the infants lung compliance is expected to change.
The following values that need to be set in this mode are:
- Vt-Tidal Volume, mL
- PEEP, cmH20
-FiO2
- Respiratory Rate
- Pmax alarm
-Slope also called Rise Time

10. PC-VG Waveforms Pressure Waveform Graph Inspiratory time
Expiratory time
Pressure gradient that the ventilator will adjust breath to breath to achieve Vt.
Time
Flow Waveform Graph In PC-VG the flow is decelerating
Vt set/given under the curve 3

11. Pressure Support Volume Guarantee (PS-VG)
Pressure Support Volume Guarantee (PS-VG) is a spontaneous ventilation mode in which each breath is supported by variable pressure to achieve the targeted tidal volume(Vt.)
Required Vent settings:
Vt, (4-6mL/Kg)
Backup rate, (BUR) bpm, ensures that the patient RR does not go below set threshold
Trigger Sensitivity (range of LPM)
FiO2
PEEP
Pmax or PIP limit
Considerations before switching to PS-VG:
All VG modes can be used with endotracheal tubes(ETT) leaks up to ~50% because the ventilator automatically adjust the PIP to deliver the set Vt.
In some cases of large ETT leaks, consider re-intubating with an appropriate size ETT

12. PS-VG Waveforms 4

13. VG with Autoflow Advantages continued
A control mode, which delivers a set tidal volume with each breath at the lowest possible peak pressure.
Delivers the breath with a decelerating inspiratory flow pattern that is thought to be less injurious to the lung…… “the guided hand”.
Pressure automatically adjusted for changes in compliance and resistance within a set range
Tidal volume guaranteed
Limits volutrauma
Prevents hypoventilation

14. Advantages of VG modes
VG has been shown to achieve equivalent ventilation and oxygenation, while delivering lower MAP (decrease risk of pneumnothorax , BPD) *E
VG reduced the breath to breath tidal volume variability , thus more stable pCO2 values( decrease risk of pneumnothorax, hypocarbia, hypercarbia, head bleeds-caused by fluctuations in CBF) *E
VG + SIMV mode achieved wean of mechanical support while maintaining equivalent gas exchange *E
PS-VG or VG-PS has the combined advantages of pressure limited, time cycled continuous flow ventilation as well as those of volume controlled ventilation *E
Again, relatively small fluctuations in breath to breath PIP’s with relatively stable Vt help to decrease ventilator associated lung injury while providing stable blood gas values which help to decrease risk of CLD and brain bleeds

15. Some Hazards and Complications of CPAP and Mechanical Ventilation:
-For CPAP:
- Gastric insufflation, pressure soars to skin and head
- Hemodynamic compromise
- Pulmonary Barotrauma or Volutrauma
- For Mechanical Ventilation:
- Barotrauma or Volutrauma
- Chronic lung disease (CLD) aka bronchopulmonary dysplasia(BPD)

16. Disadvantages to PS-VG
Large ETT leaks can overestimate the actual tidal volume delivered
The ETT leaks can be variable depending on the inspiratory pressure, neck position and the position of the endotracheal tube itself
If the baby has poor or weak respiratory drive the breath to breath measurements by the ventilator may not fully deliver the set tidal volume.

17. Caring for the mechanically ventilated baby
Roles of the Respiratory Therapist
-Maintain ventilator function, adjust settings per order, assist nurses with patient care, educates family and others, assess patient on routine basis checking ETT placement, stability and skin breakdown
Roles of the Nurse for the baby on a ventilator
Nurse can adjust FiO2 as needed to maintain SpO2 range TBD
Suction ETT(numbers to numbers matching)
Assist RT in keeping circuit in a down drain direction as to not lavage baby
Reposition the baby’s body, head or neck to minimize leaks around ETT and also to maintain ETT stability
Oral care and other general NICU RN duties

18. Roles of the RT and RN working together
Must have open communication at all times
Compare ventilator settings at beginning of shift
Discuss possible goals and interventions for the baby as relayed by the NNP or Neonatologist
Coordinate hands on time with RT therapy times(neb tx’s, suctioning, chest PT)
Coordinate times for getting Cap gases and having RT at bedside when blood drawn
Coordinate times for parent to hold baby while on the ventilator
Coordination and cooperation prior CXR’s to note the exact position of the ETT

19. Alarm scenarios Apnea High RR Low Pressure High Pressure
Low Minute Ventilation
Flow Measurement Inop
Vt not achieved
Look, Listen, Look, Listen, Assess
Other Alarms and situations

20. References Other resources:
1. -M Keszler, KM Abubakar - Clinics in perinatology, 2007
2. -
by C Riley - ‎2003
3.-
4.- Keszler M. Clinical Guidelines and Observations on Babylog with Pressure Support Ventilation
(PSV) and Volume Guarantee (VG)
Other resources:
- ”A Practical Guide to Neonatal Volume Guarantee Ventilation- C Klingenberg; K I Wheeler; P G Davis; C J Morley, J Perinatol. 2011;31(9)
- ”Better Practices: Volume Guarantee Pressure Support (VGPSV);
- Manual of Evita Series Ventilator-Drager Medical