High Flow Nasal

Cannulae Therapy in

Infants with Bronchiolitis

Dr. Michele Pennica

Terapia Intensiva Pediatrica

AOU Meyer

BRONCHIOLITIS - EPIDEMIOLOGY

Common in young children

Most common between December and March

Usually affects young children (< 1 – 2 yo) with peak of incidence between 2 and 8 months of age

1. 90% children 0-2y experience RSV infection

2. 20% have lower respiratory infection

3. 3% require hospitalization

4. 20% cause hospitalization in infancy

5. 0.002% mortality (2/100,000 children)

BRONCHIOLITIS - ETIOLOGY

Respiratory syncytial virus (RSV) accounts for 50 – 70% of cases

Other etiologies: 1. Parainfluenza 1, 2, and 3

2. Rhinovirus

3. Influenza A and B

4. Adenovirus

5. Rarely, Mycoplasma, Enteroviruses

BRONCHIOLITIS -PATHOPHISIOLOGY

Cell death (RSV cell to cell transfer and syncytial formation)

Sloughing produces airway debris

Mucous production, airway edema, mononuclear cell infiltration

Narrowed airways and turbulent flow

Plugging leads to hyperexpansion and atelectasis slough

BRONCHIOLITIS – PRESENTATION

AND DIAGNOSIS

History - URI for 1 – 2 days; fever in 1/3 of patients

- Signs and symptoms of lower airway disease

- Worsens over 2 – 5 days

Physical examination - Apnea in young infants

- URI symptoms

- Tachypnea, cough, wheezes, rales,

retractions

Supplementary tests add little

BRONCHIOLITIS – ANCILLARY TESTS

“Clinicians should diagnose bronchiolitis

and assess disease severity on the basis

of history and physical examination.

Clinicians should not routinely order

laboratory and radiologic studies for

diagnosis.”

AAP Guideline 2006

BRONCHIOLITIS – SEVERE DESEASE

Severe disease more common with background illness

- Cyanotic congenital heart disease

- Bronchopulmonary dysplasia

- Congenital immunodeficiency

- Metabolic and Neurological disease

Predictors of severe disease in - Prematurity

- Age < 12 week

CASE PROGRESSION

Can any treatment prevent

intubation?

BRONCHIOLITIS

AMERICAN ACADEMY of PEDIATRICS

AMERICAN THORACIC SOCIETY

EUROPEAN RESPIRATORY SOCIETY

AMERICAN COLLEGE of CHEST PHYSICIANS

AMERICAN ACADEMY of FAMILIY PHYSICIANS

BRONCHIOLITIS

One of the major problems with

interventional trials in infants and children

with bronchiolitis is the difficulty in

distinguishing bronchiolitis caused by

primary infection from virus induced

wheezing or asthma

BRONCHIOLITIS – SUPPORTIVE

CARE

Evaluate for possible bacterial infection and treat it

Ensure adequate hydration

Nasal suctioning

Antipyretics

Close follow up or monitoring

RECOMMENDATION

Bronchodilators should not be used routinely

in the management of bronchiolitis

A carefully monitored trial of adrenergic

medication is an option.

Inhaled bronchodilators should be continued

only if there is a documented positive clinical

response to the trial using an objective

means of evaluation (AAP 2006, Cochrane Database

Syst Rev 2011)

RECOMMENDATION

Current evidence suggests nebulised 3%

saline may significantly reduce the length of

hospital stay among infants hospitalised with

non-severe acute viral bronchiolitis and

improve the clinical severity score in both

outpatient and inpatient populations (Cochrane Collaboration 2013)

RECOMMENDATION

Corticosteroid medications should not be used

routinely in the management of bronchiolitis (N Engl J Med, 2007) (Cochrane Rev, 2010)

Despite the treatment options

suggested by the literature, oxygen

supplementation remains the mainstay

therapy for bronchiolitis

RECOMMENDATION

Supplemental oxygen is suggested if oxyhemoglobin saturation (SpO2) falls persistently below 90% in previously healthy infants.

If the SpO2 does persistently fall below 90%, adequate supplemental oxygen should be used to maintain SpO2 at or above 90%.

Oxygen may be discontinued if SpO2 is at or above 90% and the infant is feeding well and has minimal respiratory distress

(Ped 2007 )

BRONCHIOLITIS –HELIOX

Insufficient power to determine effect on need for

invasive ventilation (Chest 2006)

In one very small study, heliox – CPAP

combination showed improved clinical

scores and enhanced CO2 clearance; no

intubations (Pediatrics 2008)

BRONCHIOLITIS –CPAP

Continuous positive airway pressure (CPAP) with or without helium-

oxygen blends has gained favor as a way to decrease work of

breathing and prevent endotracheal intubation in children with

progressive hypoxemia or hypercarbia.

However, a systematic review found the evidence regarding CPAP for

bronchiolitis to be inconclusive because of methodologic limitations in

the existing studies.

Additional studies are necessary to clarify the benefits of CPAP for

infants with bronchiolitis who are admitted to an intensive care

(Curr Op Ped 2011, Pulmo 2011, Acta Ped 2010 )

BRONCHIOLITIS –CPAP

Increased CO2 in severe bronchiolitis

Improved CO2 clearance with CPAP

Bronchiolitis - NIV

NIV was safely and effectively used to support infants with

respiratory distress due to severe bronchiolitis. Prospective

randomized controlled trials are now required to delineate the

differing roles of the various modalities and predictive clinical

indicators of which patients can be successfully managed by

NIV. ( Ped Pneumo 2012 )

Oxygen therapy administered via a heated humidified

highflow nasal cannula (HFNC) has recently been

introduced in clinical practice and is gaining

widespread popularity – even outside the intensive

care setting – because it has proved to be a well-

tolerated, non-invasive form of respiratory support High flow nasal cannulae therapy in infants with bronchiolitis. J Pediatr 2010;

Pilot study of vapotherm oxygen delivery in moderately severe bronchiolitis. Arch Dis Child

2012

High Flow Nasal Cannula Therapy

High Flow Nasal Cannula Therapy

A heated, humidified circuit with a blended

oxygen source used to deliver flows that

exceed the patient’s inspiratory flow rate;

this eliminates the entrainment of room air

and purges the nasopharyngeal space of

end expiratory gases.

The goal is to decrease the work of

breathing.

High Flow Nasal Cannula Therapy

Devices are now available which warm and humidify air so flow rates of 2 l/min – 40 l/min can be delivered

Widely used in neonates with RDS

Has also been used in infants, older children and adults in ICU setting

Early studies of its use in children with bronchiolitis have been promising

Use is feasible and secure in pediatric ward

High Flow Nasal Cannula Therapy

HFNC improve the ventilatory status by:

• Prevention of mucous dryness and

improvement of mucous-ciliary clearance,

• reduction of energy expenditure for gas

warming and humidification,

• provision of continuous positive airway

pressure, which contributes to the

maintenance of patent alveoli, improves

the ventilation perfusion mismatch, and

prevents microatelectasis

Pediatr Crit Care Med 2011

INSPIRATORY PEEK

L/min

% O2

delivered flow rates.

HIGH FLOW

Flushes out the dead space in the NP cavity: - Reduce overall dead space - Alveolar ventilation becomes greater - Improves fraction of alveolar oxygen - May lead to improved CO2 elimination ( Respiratory Medicine 2009 )

1500g <pazienti <3500g

830g < pazienti < 1500g

Kubicka 2008 Pediatrics Heated Humidified High Flow Nasal Cannula Therapy : Yet another way to deliver CPAP ?

- Larger nasal prongs and decreased leak increase measured pressures - More predictable in smaller infants (neonates) - Increases with increased flow rate - Decreases and less predictable in patients whose mouths are open

Parke 2011 Respiratory Care The effects of flow on airway pressure during Nasal High Flow oxygen therapy.

a 35 L/min, CLOSED MOUTH

The first studies on the effect of the HFNC in children with bronchiolitis were carried out at intensive care units

(High flow nasal cannulae therapy in infants with bronchiolitis. J Pediatr 2010)

Their retrospective data showed a reduction in the intubation rate and an improvement in the respiratory distress associated with the introduction of HFNC

(Reduced intubation rates for infants after introduction of high-flow nasal prong oxygen delivery. Intensive Care Med 2011)

High Flow Nasal Cannula Therapy

A pilot study conducted by Padova

group showed that the HFNC is a

feasible oxygen delivery method in

infants with moderate–severe

bronchiolitis hospitalized in a

pediatric ward setting, and it is

associated with improvement in

respiratory rate and endtidal carbon

dioxide.

(Effects of high flow nasal cannula oxygen

therapy on infants with bronchiolitis in a pediatric

ward setting. Pneumologia Pediatrica 2012)

High Flow Nasal Cannula Therapy

HFNC seems to be a promising form of respiratory

support even for usage outside the intensive care.

Setting randomized controlled studies are needed

to investigate its safety and effectiveness in order

to reduce hospital stays and transfers to the

intensive care unit, as well as its long-term

benefits and economic impact on the healthcare

system.

High Flow Nasal Cannula Therapy

Recent report of serious air leakage syndrome

complicating HFNC therapy in infant with

bronchiolitis underscores the need for extreme

caution in using HFNC for the off-label indication

of providing positive distending pressure in

children, especially at flows higher than the

patient’s minute ventilation. (Serious air leak syndrome complicating high-flow nasalmcannula

therapy: a report of 3 cases. Pediatrics 2013)

High Flow Nasal Cannula Therapy

Highflow nasal cannula use in children with respiratory

distress in the emergency department: predicting the need

for subsequent intubation. Ped Em Care 2013

Determine the clinical and patient characteristics that predict success or failure of HFNC therapy in children presented to the pediatric emergency department (PED) with respiratory distress.

In infants with respiratory distress presented to the PED, triage respiratory rate greater than 90th percentile for age, initial venous PCO2 greater than 50 mm Hg, and initial venous pH less than 7.30 were associated with failure of HFNC therapy. A diagnosis of acute bronchiolitis was protective with respect to intubation following HFNC. This finding may help guide clinicians who use HFNC by identifying a patient population at higher risk of failing therapy.

Initiating HFNC Therapy

1. HFNC should be administered by physicians, nurses and respiratory therapists experienced in its use. Children needing HFNC require close monitoring and may require escalation of care.

2. High flow rates require a heated, humidified breathing circuit and an interface with a blended oxygen source.

3. Flow rate should exceed the patients inspiratory flow rate.

4. Patients requiring HFNC and FiO2 > 40% should be cared for in an ICU setting; patients who require rapid escalation to HFNC even at lower FiO2 should be strongly considered for ICU admission.

5. HFNC may lead to stabilization in patients awaiting transfer or ICU admission.

HFNC complication

No reports of pneumothorax outside

neonatal age group

Little risk of facial/nasal trauma

May mask hypoventilation and impending

respiratory failure

Predictors of failure in infants with viral

bronchiolitis treated with highflow, high humidity

nasal cannula therapy.

History of prematurity and the patient's age did not increase a patient's risk of failure.

Nonresponders to highflow nasal cannula therapy were on the onset, more hypercarbic, less tachypnoic prior to the start of highflow nasal cannula,

Had no change in their respiratory rate after the initiation of highflow nasal cannula therapy.

( Ped Crit Care 2012 )

HFNC componenet

1. Humidifier – to warm and humidify respiratory gases

2. Respiratory circuit that preserves temperature and

humidity to the patient

3. Nasal cannula that connects to the circuit

Current commercial models:

- Vapotherm 2000i™ and Precision Flow™

- Fisher and Paykel MR 850™ system

- Locally “constructed” models

Age (Monts) Weight (Kg) Days Disease INT

6 7 2

24 12 8

1 3,4 7

1 3,7 2

2 4,6 7

1 5 10 yes

8 5,2 2 FC

18 days 2,3 1 Prematurity

2 5,1 1

3 8,6 7

9 9 1

3 5,5 9 Pulm Hyper yes

2 2,4 2 Prematurity

1 3 7

1 3,7 2

2 5,1 1

3 8,6 8

9 9 1

Age (average): 4 monts

Weight (average): 5,7 Kg

Not INT

INT

Intubation11%

CONCLUSION

Bronchiolitis is the most common lower respiratory tract infection in the first year of life and the primary cause of hospitalization in infants;

Despite the growing literature investigating treatment options with recent positive data about the use of nebulized hypertonic saline and epinephrine, oxygen supplementation still remains the best therapy.

CONCLUSION

Oxygen therapy administered by heated,

humidified highflow nasal cannulae (HFNC) has

been shown to reduce the intubation rate and to

improve respiratory distress in children hospitalized

in intensive care units for bronchiolitis.

HFNC has proven to be a well tolerated, non-

invasive respiratory support which provides a

humidified and heated airoxygen blend at a flow of

1 to 8 l/min

CONCLUSION

The advantages of HFNC over nasal continuous positive airways pressure, such as easy use and improved tolerance with minimal nasal trauma, have led to increasing utilization, outside the intensive care unit as well.

Lack of data on the feasibility of HFNC in infants with bronchiolitis.