Chapter03

Bedside Management Strategies for infants on bubble CPAP

Mohamed. A. Mohamed, MD, MS, MPH

INTRO

Managing infants on bubble continuous positive airway pressure (bCPAP) is like learning how to bike. The beginning is always difficult, it needs a lot of training and it requires careful attention to the details. However, it is healthy for the driver, less costly and better for the environment. Same for bCPAP. Starting a bCPAP program is not easy, but it is feasible and achievable. It needs extensive training for all staff members; physicians, nurse practitioners, bedside nurses, respiratory therapists, and feeding specialists, and it always demands careful attention to details. However, it yields better outcomes; is less costly in terms of comorbidities; and eventually reduces health costs.

In this chapter we will discuss management strategies, including:

When to manage infants with bCPAP:

  • When you should, you may, or you may not use bCPAP

How to manage infants on bCPAP?

If the infant is stable on bCPAP:

  • How to “cruise” the infant on a day-by-day trip on bCPAP
  • How to start and advance feeding while on bCPAP
  • How to manage abdominal distention on bCPAP
  • If the infant has a murmur and you suspect a patent ductus arteriosus (PDA), how to manage a PDA while on bCPAP
  • How to “wean” the infant off bCPAP

IF bCPAP is not providing the sick infant with enough respiratory support:

When and how to “escalate” the intervention:

  • How to “maximize” bCPAP
  • Using inhaled Nitric Oxide (iNO) with bCPAP
  • When to consider NIPPV? And how to do it
  • When to intubate the infant and use invasive mechanical ventilation

Case (0): A Common encounter

Late preterm infant with respiratory distress

You are called to assess this male infant with respiratory distress and desaturations at one hour of life. Infant is a baby boy 34 5/7 weeks gestational age (GA) with a negative perinatal history. He presented at birth with respiratory distress and was given two rounds of face mask CPAP in the delivery room. He improved and was transferred to the newborn nursery for observation.

Currently, the infant is in moderate distress with a respiratory rate (RR) in the mid-70s and oxygen saturation (SpO2) that is fluctuating between 87-92%.

This is a relatively common encounter. The number of full- and near- term infants who present with respiratory distress and require respiratory support is more than the number of very low birth weight (VLBW) infants managed with bCPAP. However, preterm infants require longer duration of bCPAP.

The most common diagnosis for full- or near- term infants presenting with respiratory distress is delayed transitioning (transient tachypnea of newborn or TTN) vs. presumed sepsis. Although straightforward, the challenge in managing these infants is in the potential for underestimating the condition.

In centers where bCPAP is not the primary mode of respiratory support, such infants may be managed with nasal cannula (NC), high flow NC, Oxy-hood or other similar interventions. In doing so, the supplemental oxygen given will feed into patent (non-collapsed) alveoli but may not reach collapsed or fluid filled ones. In such case, oxygen will mask hypoxemia and may give false sense of improvement to the managing clinician. These infants usually end up by treating themselves through continuous grunting (generating a peak end expiratory pressure) and distending their own collapsed alveoli.

However, oxygen flow without pressure to distend and recruit collapsed alveoli will not fix the ventilation/perfusion (V/Q) mismatch. If no improvement over the first few hours and no spontaneous lung recruitment takes place, continued hypoxia may lead to reactive pulmonary vascular constriction and consequently persistent pulmonary hypertension (PPHN) and potentially end on extracorporeal membrane oxygenation (ECMO).

Bubble CPAP for infants with respiratory distress

  • Early use of bCPAP in full- or near- term infants with mild – moderate respiratory distress
  • Proper recruitment of collapsed alveoli
  • Improved ventilation/perfusion (V/Q) mismatch
  • Improved oxygenation
  • Early wean of bCPAP to RA
  • Shorter length of stay/ avoid progression to PPHN

If this infant develops PPHN, is there a role for inhaled Nitric Oxide (iNO) with bCPAP?

bCPAP X-Ray of baby chest

Managing team should look for signs of PPHN such as

  1. Excessive increase in FiO2 requirements with no significant parenchymal lung disease on chest x-ray.
  2. History suggestive of inefficient respiratory management with supplemental oxygen and prolonged borderline oxygen saturation (SpO2).

Inhaled Nitric Oxide (iNO) could be incorporated into the bCPAP circuits at the inspiratory arm. Start dose range from 10-20 ppm. It could be increased in increments of 5 ppm. Max dose usually 20 ppm. Some clinicians start with 20 ppm and do not advance further. Infants usually start to improve in 2-4 hours. It may take longer, sometimes, to relieve the pulmonary vasoconstriction.

Usually, infants can be weaned off supplemental oxygen in a few hours, rarely, it may take a few days.

Case (2): The Ideal Candidate

28 Week > 750 gram infant

You are in the delivery room resuscitating a 28 3/7 week female infant who is 823g with face mask CPAP. She has moderate respiratory effort, her heart rate is 140, she has good color and (+1) tone. What is your next step?

In such a clinical scenario, bCPAP should be strongly considered. It is frequently associated with a high success rate in this clinical scenario with less complications compared to intubation. It will increase the NICU staff’s confidence in their readiness to manage premature infants with bCPAP.

The benefits of bCPAP in this population are:

  1. splints alveoli and prevents alveolar collapse
  2. increases functional residual capacity (FRC)
  3. conserves surfactant
  4. increases lung compliance
  5. splints airway and diaphragm
  6. stimulates lung growth

Keys for success:

Initiation of bCPAP

CPAP is applied from the very beginning:

  • in delivery room (DR) via face mask (NeoPuff or Carden valve free flow)
  • bCPAP set-up should be always ready in the NICU
  • infants are to be transferred to NICU on face mask CPAP and immediately started on bCPAP upon admission

Maintenance of bCPAP

  • As bCPAP is a respiratory support system that maintains steady positive pressure in the newborn’s airway during spontaneous breathing, it requires meticulous attention to the patency and continuity of its circuits.
  • Proper suctioning every 2-3h (1st 3 days) then every 3-4h and as needed thereafter. Proper suctioning involves:
  1. Use of the appropriate size suction catheter for the size of the infant (8 vs.6 fr)
  2. Passing the catheter down to hypopharynx to ensure suctioning of all thick secretions or blood clots
  3. Use of superficial suctioning if nasal passages are inflamed, or bleed easily
  4. Characterizing retrieved secretions. If secretions are not clear/white this may reflect infection.
  • Care of nasal prongs
  1. Prongs size needs to be upgraded with gradual relaxation/dilation of the nasal apertures and infant’s natural growth
  2. Nasal septum needs to be examined frequently (every 3-4 hours) to avoid erosions as per bedside checklist.
  3. Bedside nurse needs to examine bCPAP check list with every care (every 3-4h)

Feeding on bCPAP

  • Feeding may start as early as the first day of life.
  • Feeding is advanced gradually (10-20 ml/kg/day after successful initiation period with trophic feeds.
  • Bolus gastric feeding is the preferred method.
  • Continuous transpyloric feeding (TP) may be considered in extremely low birth weight infants or those with severe gastroesophageal reflux disease (GERD). Transpyloric feeding may start only after assuring that the infant can tolerate bolus feeding up to 40 ml/kg/day.
  • Raising the infant’s head side of the bed may help in moving diaphragm against the full stomach.
  • Bowel distention of bCPAP babies is usually benign.

Weaning off bCPAP

  • Infants are continued on bCPAP as long as they need respiratory support and then weaned directly to room air when:
    • They have been on bCPAP PEEP +5 and FiO2 21% for at least 48 hours.
    • Weight is approximately 1200-1400g and GA is approximately 32 weeks.
    • Weaning off bCPAP starts by taking bCPAP off the infant once a day.
  • Place the infant back on bCPAP if apneas, bradycardias, desaturations or severe tachypnea develop or increase in frequency or severity.
  • Weaning off time should gradually increase as long as infant is stable until completely without bCPAP on room air.
  • Do not trade bCPAP with FiO2. If there is any doubt of respiratory compromise during the weaning process, do not wean.
  • It is better to anticipate and prevent lung collapse rather than manage a collapsed lungs.

Case (3): Relative Challenge

25 WK(GA) < 750 GM

You are called to attend the delivery of a 25 2/7 week pregnant mother who:

  • Presents with premature contractions and intact membrane since yesterday
  • She is GBS negative and was started on antibiotics
  • She completed her second dose of betamethasone 6 hours ago

Neonatal resuscitation sequence:

  • Membranes ruptured at time of delivery
  • A female infant was delivered vaginally (BW 628g)
  • Infant was initially apneic, limp, with HR <80
  • Bag and mask ventilation was initiated for a total of 2 minutes, heart rate improved to ~120 bpm, color improved, and the infant began to cry weakly

Bubble CPAP success factors in this infant:

  • GA & BW are not extremely immature (however, we advise to follow the multiphasic schedule on how to introduce bCPAP in your unit. Start with infants > 32 weeks GA then gradually advance to smaller and less mature infants (see Quality page starting bCPAP program at your unit)
  • Mother received steroids
  • Infant has uncomplicated course in the delivery room
  • Low risk for intrapartum infection

The 25 2/7 week infant was stable on bCPAP PEEP +5/ 27% FiO2 for a day, but at 24 hours of life her FiO2 requirement started to gradually increase. You decided to continue the same management and check a blood gas later…

At 36 hours of life, the infant’s FiO2 is up to 38% with moderate retractions, Arterial blood gas (ABG) was: pH 7.25/ PCO2 52/ PO2 58/ BD -5. What is your next step?

Before considering bCPAP failure check circuits for gas leaks

  • Be sure nasal prongs are snugly fitting in nasal apertures, consider larger prongs
  • Suction infant’s nose to remove excessive secretions or blood clots
  • Be sure the infant is positioned properly with head of bed elevated at least 30 degrees and the neck roll is in place where neck is extended and infant’s head is slightly falling back
  • Be sure respiratory tubes are attached to prongs properly
  • If infant does not appear to be in distress, obtain repeat blood gas
  • Consider increasing your bCPAP up to +6 cm H2O and check gas in 2-4 hours

Now infant’s FiO2 is 47% and her ABG is:

pH 7.22/ PCO2 64/ PO2 40/ BD -9

What is your next step?

In some cases, bCPAP fails because of severe apnea and the newborn’s inability to generate proper minute ventilation to wash out CO2.

Criteria for bCPAP failure

Premature infants on bCPAP need higher levels of respiratory support such as non-invasive positive pressure ventilation (NIPPV) or mechanical ventilation (MV) if:

  • FiO2 > 50% (relative to your experience)
  • PCO2 > 65 mmHg
  • Persistent metabolic acidosis with BD < -10
  • Marked retractions, frequent apneic, or bradycardic events

Before intubating the infant try NIPPV:

  • NIPPV may save VLBW infants who didn’t respond to bCPAP from intubation and you may switch them back to bCPAP in 1-3 days.
  • Suggested initial settings: PIP 18/ PEEP (5-6)/ IMV 40/ Ti 0.4-0.45 (titrate as needed)
  • Monitor abdominal girth and decompress stomach by frequently venting orogastric tube
  • Monitor blood gases closely to avoid hypo or hyperventilation

At 36 hours of life, the infant’s FiO2 is 52% and her ABG is:

  • pH is 7.20/ PCO2 68/ PO2 35/ BD -11!
  • What is your next step?
  • This infant requires intubation. Likely, this infant has significant alveolar collapse and will need surfactant. An INSURE approach (INtubate, give SURfactant, then Extubate) may be considered. However, the infant may remain on MV for a few hours until proper alveolar recruitment ensues, then infant should be extubated.

The infant now is 14 days old, 728g

  • She has been on bCPAP PEEP +6 / FiO2 23-28% since she was extubated on her 3rd day of life.
  • Yesterday, she started to have more apneic and desaturation events than her baseline
  • Her CBG reflects a mixed respiratory and metabolic acidosis

How should you proceed?

Late respiratory distress is usually not a result of bCPAP failure

This clinical picture does not resemble the initial bCPAP failure associated with severe premature lungs presenting early in life.

You need to examine other causes

  • Airway obstruction (blood in the nose)
  • GERD: higher volumes of enteral feeding (>1 wk)
  • Severe anemia (Hct <35%)
  • Severe apnea of prematurity
  • Sepsis/ pneumonitis/ NEC

If you rule out all of the above conditions, consider one dose of Lasix 1-2 mg/kg/dose to reduce interstitial edema. If there is no improvement, you can place the infant on NIPPV to reduce work of breathing and improve FRC through recruiting lung volume.

Patent Ductus Arteriosus (PDA) in infants on bCPAP

Another form of decompensation presents as a PDA.

Over the last few days, she started to have increasing oxygen requirements. Now she is on +6/ 38%. However, she has been tolerating her feeds with no observed increase in her bradycardic or oxygen desaturation events

Her current assessment:

  • Tachycardia ~160 bpm
  • III/VI systolic ejection murmur with bounding pericardial pulses.
  • B/P 48/24 (32)
  • pH 7.28/ PCO2 61/ PO2 35/ BD -3

This infant now has a PDA. However, the infant is not showing signs of severe symptoms (pH is > 7.25, BD (-3) and tolerating her feeds. The PDA could be managed conservatively with fluid restriction (140 ml/kg/d) and mild diuretics. There is a great chance that the duct will close on its own. Echocardiographic examination could be diagnostic and for follow up of duct closure, however, bedside assessment may be enough in low resources settings.

Case (4): A Mastering level of competency is required

The 23 Weeks < 500g infant

You are counseling a 23 4/7 week pregnant mother who was admitted this morning with PROM

  • During fetal ultrasonography this am, the expected fetal weight (EFW) was 470g
  • Mother has strong contractions every 5 minutes.

How would you plan to manage this newborn infant if delivered today?

The Spectrum of Respiratory Distress Syndrome

If you are a bCPAP starter: “Do Not” consider bCPAP in the “Initial” management of this infant. There are several factors that increase the chance for this infant to fail initial management with bCPAP:

  • Severe lung immaturity
    • Lung development is in the respiratory bronchiole phase
    • Low number of developing alveoli
    • Narrow collapsible airways
  • Reduced muscle mass
  • Excessively compliant chest wall
  • Severe apnea of prematurity

You may consider INSURE strategy for this infant or non-invasive instillation of surfactant

Insure Strategy

  • INtubate-SURfactant-Extubate (intubate, give surfactant and extubate)
    Infants who are likely to need mechanical ventilation should be intubated and given surfactant as early as possible
  • Infants who are not likely to need mechanical ventilation should not be exposed to the risk of intubation

Another alternative is to give surfactant non-invasively though MIST, LISA or LMA (see chapter: Contemporary Methods for Surfactant Administration in Neonates)

  • Your 23-week infant was delivered the day after
  • In the delivery room, infant didn’t breath and was limp and cyanotic
  • After initial bag & mask ventilation, HR was 80 bpm but apnea continued
  • Baby was intubated and bag ventilated
  • HR, tone and color improved

The newborn infant was transferred to the NICU:

  • Infant was placed on mechanical ventilation with PIP 20/ PEEP 5/ IMV 40/ FiO2 60%
  • Central lines were placed and surfactant was administered
  • Infant gradually stabilized and vent settings were gradually weaned…

Scenario for early extubation after surfactant administration

After 36 hours of life, infant is on

  • SIMV PIP 17/PEEP 5/ IMV 25/FiO2 27%
  • Trophic feeds of BM at 1ml q4 via orogastric tube

Do we have room for bCPAP?

  • This infant is relatively ready for extubation
    • You may extubate directly to bCPAP and if apnea develops you may switch to NIPPV

OR

  • You may extubate to NIPPV and if stable in 24-48h you can wean to bCPAP

On DOL#7 the infant has been on bCPAP over the last 2 days, after 2 days of intubation and mechanical ventilation and 3 days on NIPPV. This morning bloody gastric aspirates were noted! What should you do?

  • Before starting your ‘NEC’ work up, check nasal septum
  • Anterior and lateral nasal septum irritation, erosion, and bleeding may be induced by the continuous pressure and/or friction from inappropriately placed nasal prongs. The bridge between nasal prongs is resting or pressing on the nasal septum or the prongs are too large in size causing lateral compression on the septum.

Prevention is a key strategy:

  • Use the correct size prongs
  • Secure prongs with fitted hat and correctly position the corrugated tubes
  • Do not allow the bridge of prongs to touch the nasal septum
  • Avoid twisting prongs. This can cause lateral pressure against the septum

Case (5): Unexplained Failure

A 31 Week who is 24 hour old but failing bCPAP

This is a 31 week female with BW 1080 gram SGA who has been on bCPAP +5/ FiO2 21% for 12h. Now she is distressed with intercostal and subcostal retractions and her FiO2 is up to 38%. What is going on?

Think “Mechanical Failure”

  • If bCPAP water bottle is not bubbling, then there is an air leak somewhere in the circuit. Remove prongs from nose and occlude them by hand to check for leak in the circuit
  • Inspiratory or expiratory limbs are disconnected or have excessive water condensation will interfere with gas delivery
  • There is a leak in the humidifier or leak in gas supply
  • Inappropriate gas flow (< 5-7 L/m)

Check nasal interface placement

  • Prongs may be outside the nose
  • Prongs are too small (inappropriate size)
  • Prongs are malpositioned
  • Is the hat fitting snugly?
  • Are the corrugated tubes fixed correctly to the hat on both sides and at the
  • Correct angle to the prongs?
  • Does the Velcro moustache need replacement?
  • Infant’s mouth may be wide open leaking air out and needs a “chin strip”

If everything is Ok do chest x-ray

  • Pneumothorax may occur on CPAP
    • It commonly occurs within first 12-24 hours
    • Could be managed conservatively with expectant management (no needle aspiration)
    • If a tension pneumothorax occurs, needle aspiration with no chest tube placement may be considered.
    • If recurred, chest tube should be placed.

Any of the above steps could be successfully achieved while on bCPAP (no routine intubation), intubation and mechanical ventilation should be considered only in unstable infants with severe hypercarbia, respiratory acidosis or bradycardia

Elements Of Success Of bCPAP

  1. Early introduction of bCPAP to all premature newborns in the delivery room. Be sure to allow time for establishing lung volume before intubation.
  2. If intubated, early extubation to bCPAP (or NIPPV) with persistent drive to reach to stability on bCPAP
  3. Continued use of bCPAP as long as infant requires respiratory support (to allow for enhanced lung growth), then gradual wean off CPAP to room air (no free flow oxygen via nasal cannula)