Non-invasive ventilation (NIV) is used to provide respiratory support in both the acute and chronic (long-term care) settings in infants and children. The term refers to ventilation support that does not involve intubation. Technological advances have resulted in improvements in ventilation strategies that offer a wider range of non-invasive modalities and increased use in children over recent years.

NIV may involve positive airway or negative extrathoracic pressures, although the latter are less commonly used in the United Kingdom. Most NIV involves continuous positive airway pressure (CPAP) or bi-phasic positive airway pressure (BiPAP) delivered by one of a number of fairly simple, portable bedside devices. They are attached to the patient by face or nasal masks or prongs. LCD displays allow adjustment of a few basic settings, such as pressure limits, respiratory rate (for mandatory or back-up ventilation), inspiratory time (Ti) and trigger sensing.

CPAP is where a constant positive pressure is applied to the airway of a spontaneously breathing infant or child to maintain adequate end pressure within the alveoli and prevent atelectasis. In current practice, binasal CPAP has superseded the single nasal prong and is most commonly administered non-invasively by a flow driver. The set-up and an example screen can be seen in the Figure. Any mode given via a flow driver should include a humidifier within the circuit to ensure the delivered gases are moistened and warmed to 37 degrees Celsius. The pressure is delivered to the child’s airway via two short prongs or a nasal mask. These are attached to the circuit manifold.

Given the relationship between flow and pressure, generally, a flow of 8–10 litres/minute should give a pressure of 4–6 cm/water, provided that there is an adequate seal at the nostrils. Altering the flow will affect the pressure given. For some children, it is necessary to increase the flow to give a higher pressure of 6–7 cm/water (subject to individual assessment by ward medical/nursing team). Oxygen delivery is controlled via a dial.

BiPAP occurs where two pressure levels are set, a background continuous measurement and a higher one, which is delivered at intervals either triggered by the neonate or set as a mandatory ‘rate’. Infant Flow SiPAP, for example, provides bi-level nasal CPAP for the spontaneously breathing infant through the delivery of ‘pulses’ or ‘sighs’ (brief periods of increased pressure) above a baseline CPAP pressure. These may be timed, or ‘triggered’ by the infant’s own inspiratory efforts.

CPAP: This is a mode itself on all ventilators as well as a support strategy in its own right known as nCPAP (nasal CPAP). On the flow driver, it can be given with or without ‘apnoea’. If CPAP with apnoea is required, then an abdominal transducer is necessary in order to monitor any apnoeic episode and raise the alarm according to the apnoea time interval, which is set by the user.

BiPAP: The following mode options are available:

• Biphasic-timed: the machine delivers a set baseline pressure using the ‘low pressure’ flow metre (set to 8 l/minute on average). The extra pressure-supported ‘sighs’ are delivered according to a set ‘rate’ and Ti. The user will set the additional pressure with the ‘high pressure’ flow metre which is set at 2 l/minute above the low pressure dial. It is important not to set the ‘high pressure’ flow too high. The user will also set the number per minute and length of each extra sigh.
  
• Trigger biphasic: as above but the extra pressure sighs are not timed. These are now triggered by the infant/child initiating a breath.
  
• Biphasic + apnoea: as for biphasic-timed but there is additional apnoea monitoring and an alarm will sound if the infant/child does not breathe within the apnoea interval.

The Figure shows how to put the nasal manifold and hat on an infant, as an example. When caring for the infant or child, a balance is necessary between an adequate seal at the nose to maintain pressure and the prevention of nasal trauma.

• Ensure the nasal prongs/mask/bonnet are sized correctly according to guidelines.
  
• Ensure the bonnet-to-nose strapping provides secure fixation but is not too tight.
  
• Position the neonate and the tubing appropriately so that it is well supported.
  
• Regularly check for nasal trauma.
  
• Assess for any discomfort and provide measures to settle and console.
  
• Continuously monitor vital signs including oxygen monitoring.
  
• Assess the need for oral/nasal suction only if required.
  
• Remember mouth care should be given regularly due to potential dryness from gases.
  
• Continue feeding while on CPAP if applicable – observe for abdominal distention – nasogastric tube should be in situ and left on free drainage if infant/child is not fed OR to be aspirated before each feed and any excess gas removed.
  
• Once the lungs have improved, provide time off CPAP/BiPAP according to individual care plan and clinical condition. Strategies for weaning pressure and discontinuation of the device are subject to local unit policy.