Nasal Intermittent Positive Pressure Ventilation (NIPPV)
The spontaneously breathing preterm infant is faced with multiple challenges, such as reduced compliance of their lungs, high chest wall mobility, small upper airways, and periodic breathing with apnoeas
Overview
NIPPV superimposes an intermittent peak pressure on CPAP and is delivered to the infant with a ventilator and Hudson prongs.
NIPPV, in particular when synchronized, improves extubation success in preterm infants, but does not seem to be beneficial for the primary treatment of RDS. NIPPV does not reduce the rate of death or BPD¹,²
NIPPV is NOT a replacement for endotracheal ventilation, it should be seen as alternative to nCPAP. Sepsis and other pathologies should always be considered in infants with increased work of breathing or other respiratory deterioration. Intubation needs to be considered for these infants.
Introduction
The spontaneously breathing preterm infant is faced with multiple challenges, such as reduced compliance of their lungs, high chest wall mobility, small upper airways, and periodic breathing with apnoeas.
Intubation and ventilation is an effective way to overcome these challenges, but is associated with side effects, such as chronic lung disease, upper airway damage and infection. The use of NIPPV, in particular if synchronized, reduces the rate of extubation failure when compared to nCPAP.
The mode of action is not entirely clear. Non-synchronised NIPPV pressure peaks only seem to cause a small increase in relative tidal volumes during spontaneous inspiration and occasionally result in chest inflation during apnoea³. The positive effect of NIPPV might also derive from increased mean airway pressure, reduced work of breathing and/or improved gas exchange⁴.
Indications
NIPPV can be considered for preterm infants after extubation withprevious extubation failure and/or on-going apnoeas. Those infants should be treated with an optimised dose of Caffeine Citrate (≥ 10 mg/kg/day). A high or increasing CO₂level is a sign of hypoventilation. Non-synchronized NIPPV might not sufficiently increase tidal volume and intubation and ventilation should be considered for infants with high or increasing CO₂.
NIPPV settings
| Ventilator (mode) | Babylog VN 500 (PC-CMV). Place baby on Neopuff if currently ventilated, switch VN500 to standby mode and start PC-CMV as described in NIPPV set-up. The screen then displays PC-CMV and NIV (non-invasive ventilation) as mode in header bar. |
| Peak Inspiratory Pressure (Pinsp) | 14 - 20 cm H2O, in discussion with a consultant may be increased to 24 cm H2O. |
| Positive End Expiratory Pressure (PEEP) | 5-8 cm H2O. Aim for the achieved mean airway pressure to be the same as if the baby would be on Hudson CPAP. |
| Respiratory Rate (RR) | 10 - 40 breaths/min, in discussion with a consultant may be increased to 60 breaths/min. |
| Inspiratory time (Ti) | 0.3-0.5s, similar to Ti on the ventilator |
| Flow | 10 L/min. This can be turned up to 20 L/min if PIP or MAP not reached and then needs to be discussed with SMO next ward round. |
| Flow sensor | Automatically deactivated in NIPPV mode. Needs to be taken out of circuit. |
| Alarms | The 'Disconnection' alarm will function. Set disconnection alarm to 20 sec. |
| Oxygen | An oxygen analyzer is not needed. Read FiO2 administered on the ventilator' screen. |
NIPPV Setup
Assemble ventilator circuit with Hudson CPAP prongs appropriate for infant's nares. Connectors from the ventilator circuit pack will fit the end of the blue and white circuit tubes and directly onto the Hudson CPAP prongs (see photo). Keep rest of packet with baby as this can be used when the baby transitions to bubble CPAP.
If the baby is currently ventilated with the VN500, then the baby needs to be connected to the Neopuff while setting up NIPPV on the ventilator.
Go to standby screen, check that the ventilator is in neonatal mode. Select Tube/NIV tab, then select NIV option (NIV = non-invasive ventilation).
Perform breathing circuit check with Hudson prongs connected to the circuit. Occlude nose piece with fingers; do not squeeze prongs shut as this may lead to increased leak (leak should be < 300 ml/min).
Go to start/standby screen, go to ventilation settings and set appropriate NIPPV settings. Press start and confirm to start NIPPV.
Open alarms, to go limits, set Tdisconnect at 20s
There will be 3 changes in the header bar:
• The ventilation mode display bar will turn orange and display PC-CMV.
• There will be a picture of a face and mask in the header bar with the letters NIV (non-invasive ventilation).
• The flow sensor will be automatically deactivated and must be removed from the circuit.
Maintenance of NIPPV
| High/low CO2 | NIPPV is NOT a replacement for endotracheal ventilation. If the infant is deteriorating, do not change the settings as if the infant was ventilated but rather intubate and ventilate. For NIPPV, there is minimal evidence in regards to the effect of adjusting pressures and rates. |
| O2 concentration adjustment | This is done on the ventilator and not on the oxygen/air blender at the bed space. |
| Charting | Document on a 'Level Three' chart. Ventilator mode is charted as NIPPV to document it is not ventilation through an endotracheal tube. |
| Recordings | Record FiO2, rate, pressures (PIP, PEEP and MAP), Ti and flow as well as vital signs hourly as per usual for 'Level Three' chart. |
| Gastric Tube | A gastric tube needs to be in place and should be frequently aspirated for air while the baby is on NIPPV. Discuss with SMO if on continuous feeds. |
| Suctioning | Suctioning should be performed to maintain maximum airway patency and is the same as for babies on CPAP. |
| Kangaroo Care | The same considerations as for CPAP apply for NIPPV with regard to kangaroo care. |
Complications of NIPPV
Complications are similar to treatment with nCPAP. (see Complications of CPAP). Appropriate nursing care should prevent nasal septal erosion and nasal obstruction.
There have been concerns regarding NEC, feed intolerance, and intestinal perforation in association with NIPPV, but a recent Cochrane review could not confirm this². Given the airway pressures with NIPPV are higher than those given with nCPAP, a gastric tube needs to be in place and should ideally be aspirated frequently to remove gastric air while the infant is on NIPPV. Discuss a plan for abdominal distention on the ward round.
Troubleshooting NIPPV
NIPPV is provided with a ventilator, therefore there is no "bubbling" noise.
'Disconnection' alarm
Check if a leak originates from the circuit or from the 'infant' as you would with an infant on bubble CPAP (see CPAP - troubleshooting)
Systematically check the circuit.
Make sure the prongs fit snugly and are positioned properly. Consider a duoderm patch, a chin strap and/or a dummy.
Check that the disconnection alarm limit is set at 20 sec.
Ensure breathing check has been completed with Hudson prongs occluded prior to starting NIPPV. If unsure, redo breathing check (see above NIPPV set up step 4)
In case the ventilator keeps alarming despite above measures, increase flow to up to 20 L/min. If ongoing alarms, lengthening Ti to 0.5 sec may reduce alarms. Make sure MAP reaches required pressure, i.e. if baby would be on Hudson CPAP 8 cmH₂O then achieved MAP should be 8 cmH₂O.
Damage to nasal septum
The risk of nasal septal damage is the same as for nCPAP and should be prevented with careful positioning of the prongs and close monitoring (see CPAP - troubleshooting). A nasopharyngeal airway is an alternative option to Hudson prongs (see 'Nasopharyngeal CPAP'). However, studies have shown that for CPAP, short binasal prongs are more effective at preventing reintubation than single nasopharyngeal prongs.⁵
Unsettled infant
Settling the infant can be difficult and time consuming. Make sure the prongs are in a good position and that the infant is positioned comfortably. If this does not improve the situation, check 'CPAP - troubleshooting'