Paediatric View of High Flow Nasal Cannula Therapy

in Bronchiolitis-a PARIS High Flow Trial

A/Prof Andreas Schibler

University of Queensland

Paediatric Critical Care Research Group (PCCRG)

Lady Cilento Children’s Hospital

Brisbane, QLD, Australia

How Does High Flow

Treatment Work?

Time for a change in Paradigm?

Objective

Oxygen

Pressure

Work

of

Breathing

Conflict of Interest Declaration: Swiss Precision

Studies funded by National Health Medical Research

Council Australia, Heart Foundation, ANZ Trustee,

QEMRF, Preston James Fund, Intensive Care

Foundation, Welcome Trust UK, travel expenses for

conferences paid by Maquet, Draeger, Visasys,

Fisher&Paykel, no personal COI

Oxygen Requirement

in presence of Lung Disease

What does the clinician need to know?

• Is a Function of Alveolar Surface

- Size of the Lung, Atelectasis and Consolidation

• Is a Function of Shunt Fraction

- ventilation-perfusion mismatch

• Is a Function of Ventilation Inhomogeneity

- affected by Physiological Dead Space

and preferential ventilation

• Is a Function of Alveolar-Capillary Membrane

- Aa-Gradient

Responds to CPAP

Responds to O2

1986

The Birth of High Flow

2001

Frey and Shann.

Oxygen administration in infants

Arch Dis Child fetal Neonatal Ed 2003;88F84-F88

2006

Saslow et al.

Work of breathing using high-flow nasal cannula in preterm infants

J Perinatology 2006;26:476-480

3 large RCT in preterm infants post extubation for RDS (2013)

High Flow is non-inferior to nCPAP

n ~ 900 infants

2015:Current intubation rate ~3-5%

PICU admission fro Bronchiolitis in Australia and New Zealand

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7 8 9 10 11 12 13

Ad

mis

sio

n R

ate

per

100,0

00

Neonatal 28 days to <90 days

90 days to <1 year 1 year to <2 years

Risk adjusted Odds Ratio for Intubation of

infants with Bronchiolitis

0.25

0.5

1

2O

dd

s R

ati

o

What is High Flow Nasal

Cannula oxygen therapy?

• No clear definition

• High Flow Nasal Cannula (HFNC) therapy is anything if:

• flow rates >2L/min in infants and

• flow rates ranges from 0.5 to 2L/kg/min in paediatrics

• with or without fraction inspired oxygen

• Maximal flow rate capped at 8L/min in the past (manufacturing

limitations)

• Heated and Humidified gas (undisputed benefits)

• Blended oxygen

Most accepted definition in bronchiolitis is:

Flow rate titrated for body weight at 2L/kg/min for infants under

12mths with bronchiolitis improves lung volume, decreases

electrical activity of the diaphragm and reduces WOB measured by

oesophagus pressures. (Pham et al)

Differences in tidal breathing between infants with chronic lung diseases and healthy controls

Schmalisch BMC Pediatrics 2005

Table 3

Comparison of TB parameters between both patient groups ordered according to the p-value of the ANOVA

(Presented are group means ± SD, statistically significant p-values after Bonferroni correction (p < 0.0028) are

printed in bold)

Parameter Healthy neonates (n = 48) CLD infants (n = 48) p-value CLD

tI(s) 0.65 ± 0.14 0.45 ± 0.11 p < 0.0001

RR (min-1) 39.2 ± 8.6 55.4 ± 14.2 p < 0.0001

(PTIF+PTEF)/VT (s-1) 0.27 ± 0.06 0.37 ± 0.09 p < 0.0001

tE (s) 0.98 ± 0.24 0.72 ± 0.22 p < 0.0001

VT/tI(mL·s-1·kg-1) 8.9 ± 2.2 11.6 ± 2.8 p < 0.0001

V'E(mL·min-1·kg-1) 215 ± 51.7 276 ± 76.8 p < 0.0001

TIF 50 (L·min-1·kg-1) 0.75 ± 0.21 0.98 ± 0.26 p < 0.0001

PTIF (L·min-1·kg-1) 0.83 ± 0.20 1.05 ± 0.28 p < 0.0001

PTEF/tPTEF (L·s-2·kg-1) 2.90 ± 1.68 5.25 ± 3.66 p = 0.0001

PTEF (L·min-1·kg-1) 0.64 ± 0.19 0.82 ± 0.29 p = 0.0006

tptef (s)*) 0.24 ± 0.09 0.18 ± 0.11 p = 0.001

TEF75 (L·min-1·kg-1) 0.60 ± 0.20 0.76 ± 0.29 p = 0.003

TEF50 (L·min-1·kg-1) 0.52 ± 0.17 0.66 ± 0.25 p = 0.003

TEF25 (L·min-1·kg-1) 0.38 ± 0.11 0.46 ± 0.16 p = 0.006

Vptef (mL/kg)*) 1.68 ± 0.52 1.37 ± 0.44 p = 0.006

VT (mL·kg-1) 5.57 ± 1.06 5.15 ± 1.35 p = 0.09

VPTEF/VT(%)*) 29.4 ± 6.6% 27.2 ± 6.1% p = 0.13

tPTEF/tE (%)*) 25.8 ± 9.7% 23.2 ± 7.8% p = 0.20

*)Loops with flow limitations, grunting or other deformations were excluded from the evaluation (6 controls, 8 CLD

infants)

Abbreviations: tI,E-inspiratory, expiratory time, RR-respiratory rate, PTIF, PTEF-peak tidal inspiratory and expiratory

flow, VT-tidal volume, TIF 50-tidal inspiratory flow when 50% of VT is inspired, TEF 75, TEF 50, TEF 25-expiratory flow

when 75%, 50% and 25% of tidal volume remains in the lung, V'E-minute ventilation, tPTEF,VPTEF-time and volume to

peak tidal expiratory flow

Schmalisch et al. BMC Pediatrics 2005 5:36 doi:10.1186/1471-2431-5-36

PTIF (L·min-1·kg-1) 0.83 ± 0.20 1.05 ± 0.28 p < 0.0001

Why should we use 2L/kg/min?

Ph

ary

nx

Pre

ss

ure

Milesi C. Intensive Care Med 2013

Physiological EvidencePlausible cause relationship of High Flow

~ 1.6 L/kg/min

PEEP

Inspiratory

Aid

High Flow Setup

Infant Oxygen Cannula

BC2745

2 L/kg/min

Blended O2/Air Heated, Humidified

Figure 1: High-flow nasal prong system used for retrievals of critically ill children. 1, nasal

cannulae; 2, distal temperature probe; 3, tubing; 4, heated humidifier, 5, oximeter, 6, flow-meter

with ventouri blender, 7, ambient air entry port through air filter, 8, Pressurized O2 access

HFNC during interhospital Transport

children < 2 years of age

How does HFNC compare to CPAP?

Early Intervention

Intubation – Ventilation - Pressure Injury

Surfactant

plus Ventilation

Surfactant

plus CPAP

CPAP23-24 gestational week survival on

CPAP only

32-36 weeks

26-32 weeks

Do

ing

les

s

Delivery Room Neonatal Intensive Care Unit

Progression of Disease

Neo

na

tal R

es

pir

ato

ry D

istr

es

s

Res

ea

rch

Emergency Department

Operating Theatre

Hospital Ward

Intensive Care Unit

Progression of Disease

Acu

te R

esp

ira

tory

Dis

tre

ss

Rese

arc

h

Emergency Department

Operating Theatre

Hospital Ward

Intensive Care Unit

Progression of Disease

Ac

ute

Re

sp

ira

tory

Dis

tre

ss

Researc

h

Study Protocol

Inclusion Criteria

* Bronchiolitis

* SpO2 <92/94%%

* < 12mths

HFNC

2L/kg/min

Control

Responder

HFNC

2L/kg/min

Non-Responder

Non-Responder

Responder

Transfer

Non-Responder

Responder

Transfer

Criteria for non-responder:

RR, HR and EWT unchanged after 120-180 min

Primary Outcome

CPAP

WOB

+-

FiO2

Control

Humidification

Standardization

Evidence

ACKNOWLEDGMENTS

PARIS Study Group

Donna Franklin

Sue Moloney

Tom Hurley

David Levitt

Marlon Radcliffe

Vishal Kapoor

John Waugh

John Coghlan

John Gavranich

David McMaster

Collin Myers

Jan Cullen

Luregn Schlapbach

Christian Stocker

Adrian Mattke

Lee O’Malley

Trang Pham

Geraldine Corcoran

Debbie Long

Tara Williams

Kimble Dunster

John Fraser

Tom Riedel

PREDICT Study Group

Stuart Dalziel

Franz Babl

Ed Oakley

Jocelyn Neutze

Simon Craig

Kam Sinn

Jeremy Furyk

Natalie Phillips

Inclusion Criteria:

1. Infants < 12 mths (corrected age) requiring

admission to your hospital

2. Diagnosed with Bronchiolitis (viral illness

characterised by coryzal symptoms for 1-3days,

then worsens on days 3-5, with increased work of

breathing and auscultatory findings of possible

crackles and wheeze)

3. Oxygen requirement with SpO2 <94% in room air

If oxygen in ambulance - turn off briefly to assess

SpO2 in room air.

Exclusion criteria:

• Upper airway obstruction

• Apnoeas

• Craniofacial malformation

• Critically ill and immediate need for Intubation and

Ventilation or NIV

• Basal skull Fracture

• Trauma

• Decreased level of consciousness

• Cyanotic Heart Disease

• Home Oxygen therapy