Download HHFNC presentation

Humidified High Flow Nasal
Cannula (HHFNC) Oxygen
therapy at Campbelltown
Hospital
Julia Parmeter (Paediatric Fellow) & Nicole Cook (CNE)
With thanks to Justin Smith (CNS)
HHFNC Oxygen Guideline
• MP4 conference in June 2014 presented data on the use of HHFNC
Oxygen in NSW NETS referrals
• Wide variability in usage
• Developed a guidelines for MP4 units and emergency departments to
provide consistent and safe clinical practice for using HHFNC in infants
Definition of HHFNC oxygen
• A system that delivers warm, humidified gas at high flow rates that
generate positive airway pressure
• HHFNC oxygen is thought to act as a bridge between low flow oxygen
therapies and Continuous Positive Airways Pressure (CPAP), reducing
the need for intubation
• High flow at 1-2 L/kg/minute generates a positive pharyngeal
pressure between 4-6 cmH2O
How does it work
Theory:
1. Humidifcation
2. Washes out oropharyngeal dead space
3. Generates positive pressure
4. Reduces energy expenditure
How does it work?
1. Humidification
• Humidification of the inhaled oxygen / blended air and oxygen
improves mucociliary clearance
• Also decreases the resistance in nasal mucosa induced by dry and
cold gas, thereby improving inspiratory flow
How does it work?
2. High flow affects the oropharyngeal dead space
• A flow higher than the patient’s inspiratory flow provides better oxygen
delivery than low flow oxygen or highly concentrated oxygen with a mask
• High flow washes out the end-expiratory oxygen depleted gas in the
oropharyngeal dead space
• In the next breath, the patient breathes in oxygen and reduces CO2
rebreathing
• Infants and children have an extra-thoracic dead space 2-3 times higher
than adults
How does it work?
3. Positive pharyngeal pressure
• Positive pharyngeal pressure results in:
• Prevention of pharyngeal collapse
• Compensates the inspiratory burden and facilitates inspiratory flow
• Prevents small airway collapse and increases expiratory time
• The pressure generated depends on:
• The flow rate
• The prong / nostril ratio
• Whether the mouth is opened or closed
How does it work?
4. Reduced energy expenditure
• The positive pressure at the time of inspiration generates an
inspiratory flow as soon as the inspiratory muscles begin working
which reduces the burden on the muscles
• Studies demonstrating decreased electrical activity of the diaphragm
and decreased oesophageal pressure swings in infants with
bronchiolitis on high flow
General concepts:
• Increased work of breathing?  Increase the flow rate
• Decreased oxygenation ?  Increase the FiO2
Indications for use:
• Moderate to severe respiratory distress in infants (0-12 months) with
bronchiolitis who have failed to respond to low flow oxygen
• May have a role in moderate to severe respiratory distress in children
who have failed to respond to low flow oxygen, but there is limited
evidence to support this
• Use for indications other than bronchiolitis may have some merit, but
should only be considered after senior medical consultation and
implementation of appropriate disease specific treatments
Contra-indications
• Neonates in special care nurseries
• Nasal obstruction (eg choanal atresia)
• Trauma (facial #, suspected base of skull #, chest wall injuries)
• Life threatening hypoxia / apnoeas / haemodynamic therapy
• Pneumothorax
• Foreign body aspiration
• Cyanotic congenital heart disease
Not a complete contra-indication, but proceed
with caution:
• Decreased level of consciousness
• Congenital heart disease
• Asthma *
• Chronic respiratory disease
*Asthma and HHFNC
• Physiologically, HHFNC seems an attractive option for asthmatic patients
• May decrease the burden on inspiratory muscles
• Heated / humidified gas may decrease the amount of bronchoconstriction induced
by cold/dry gas
• The high flow should theoretically improves the distribution of inhaled treatment
• However, the dose of bronchodilator received varies between 0.5% to 25%
of the administered dose
• Limited evidence for the use of in line mesh vibration nebuliser adaptor
Asthma – recommendations at Campbelltown
• Any child requiring metered dose or nebulised medications (eg
salbutamol) during HHFNC need to have the high flow ceased or have
the flow significantly reduced (<4L/min) during the time of
administration
• If no significant clinical improvement, cease high flow and treat the
asthma
What do Paediatrics want to hear?
• History
• HPC: duration of symptoms, presence / absence of seizures
• PMHx: previous hospital admissions, known medical conditions, allergies,
immunisation status etc
• Examination findings
• Relevant investigations
• NPA
• Chest x-ray
• Bloods
• Differentials...
What do you need to do before starting high
flow?
• The most senior doctor (paediatric or emergency) should have reviewed
the patient and the Paediatrician on call must have been informed and
agreed to the use of HHFNC oxygen
• Informed consent from the parent or carer and documented in the notes
• Prescription of high flow, including the FiO2 and flow rate in L/kg/min
should be documented
• Flow 1L/kg/minute
• FiO2 40%
Starting Parameters
1. Flow
• Commence at 1L/kg/min
• Improvement defined by a reduction in heart rate by 20% (equates to a trend from red to
yellow or yellow to blue ones on SPOC chart)
• A decrease in respiratory rate and WOB should follow
• If no improvement to WOB, heart rate and respiratory rate after 15 minutes, titrate up to
2L/kg/min to a maximum of 25 L/min
• If no improvement within 60 minutes on 2L/kg/min (or max 25 L/min), the patient needs
senior medical review and escalation of therapy
2. FiO2
• Commence with 40% FiO2
• Titrate up or down to maintain oxygen saturations between 92-98% – to a maximum of
60%
• If unable to maintain saturations above 92% at a maximum of 60% FiO2 – get help
What is the set up?
• Equipment:
•
•
•
•
•
•
•
Oxygen and air source
Oxygen blender or oxygen analyser
Flow meter 0-30 L/min
Humidified base and Humidifier circuit
Nasal cannula
Sterile 2L water bag
Nasogastric / orogastric tube
HHFNCO2 Set Up
Please refer to,
NSW Kids and Families, Humidification High-Flow
Nasal Cannula Oxygen: Standards for Metropolitan
Paediatric Level 4
Units, NSW Health 2015
for more comprehensive set-up instructions.
Nasal Cannula Selection
As the size of nasal cannula has been demonstrated to
impact on the level of CPAP in preterm infants, but has not
been established in the paediatric setting, the following
parameters should be utilised.
“At all times a slight visible gap should be seen
between the nares and the nasal cannula”
The 2 available nasal cannulas on our ward are,
· Fisher & Paykel OPT316 (Infant) - Maximum flow of 20L/min.
· Fisher & Paykel OPT318 (Paediatric) - Maximum flow of 25L/min.
PLEASE REMEMBER: A MAXIMUM OF EITHER 20 OR 25LOF FLOW
CAN BE ACHIEVED WITH OUR CURRENT EQUIPMENT
Ongoing care
• Medical review must occur again within 1 hour of commencement of
high flow therapy and 4 hourly at a minimum if patient stable at the 1
hour review
• Patient should be nursed with a patient ratio of 1:2 in Close
Observation Area by a registered nurse experienced and educated in
paediatric nursing care
• If patient remains stable after 24 hours of HHFNC therapy, ongoing
medical review should occur 4-8 hourly
Monitoring requirements
• Continuous cardio-respiratory monitoring
• Continuous oxygen saturation monitoring
• Hourly check and documentation of FiO2, flow and circuit
• 4th hourly temperature check
• Blood pressure check once per nursing shift, unless abnormal
• Blood glucose level 6th hourly for fasting infants
Other care concerns
• Nasogastric tube
• Feeding
• Not contra-indicated – depends on respiratory status and clinical situation
• Continuous feeds vs IV fluids
• IV fluids generally 2/3 maintenance
• IV access
• Consider need for antibiotics
Not improving?
• ? Pneumothorax
• ? Aspiration
• ? Nasal trauma
• ? Equipment problem
• ? Need to escalate therapy
• ? Right diagnosis
Notify Paediatrician & consider NETS consultation
Weaning HHFNC Oxygen
• When to wean:
• Mild or no increased work of breathing
• Normal parameters (HR, RR)
• Saturations >92%
• Order of weaning:
• Wean FiO2 by 10% increments (aiming to maintain SpO2 >92%)
• Once needing less than 40% FiO2 with minimal work of breathing, decreased flow rate
• First to 1L/kg/min
• If child remains stable for 2-4 hours, then reduce again to 0.5 L/kg/min and then cease
• If flow is under 2L/min and there is still an oxygen requirement, swap to low flow oxygen
• Cease once child is in 21% O2 and <4L/min
Case studies from 2016
1. MR
• 4 week old boy brought in by parents with cough and increased work
of breathing, poor feeding. Day 2 of symptoms.
• Antenatal history – NAD
• HR 150, RR 48, Sats 95% room air, afebrile. Mild to moderate work of
breathing, bilateral crackles and wheeze
• Admitted to paediatric ward. Commenced on oxygen 2L via NP for
work of breathing.
• Gradual increase in work of breathing
• NPA – RSV +
Observation Chart
Progress
• VBG:
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•
•
•
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pH 7.28
pCO2 55
HCO3 26
BE -1
Lactate 2.6
• Commenced on HHFNC 1L /kg/minute FiO2 40%
Observation Chart
High Flow Commenced
Progress
• Titrated up to 2L/kg/minute, FiO2 30%
• Repeat VBG:
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•
•
•
•
pH 7.33
pCO2 44
HCO3 26
BE -1
Lactate 1.9
Observation Chart
High flow ↑2L/kg/min
Progress
• Clinical improvement
• FiO2 weaned to 21%
• Flow rate gradually weaned and ceased.
• Discharged home after 3 day admission.
2. AU
• 7 week old infant presented to ED with significant respiratory distress
• 3-4 days of cough and runny nose, 1 day increased work of breathing.
Poor feeding
• Antenatal history - NAD
• On presentation to ED – RR 55, grunting, prolonged expiratory phase,
HR 190 bpm, mottled and tachycardic.
• Commenced 2L/min NP oxygen.
• Ongoing work of breathing
• NPA – RSV +
• VBG:
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•
•
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pH 7.24
pCO2 65
HCO3 28
BE 0
• Commenced HHFNC 1L/kg/minute FiO2 30%
Progress
• Admitted to Paediatric ward
• Titrated to 2L/kg/minute FiO2 40%
• Ongoing severe WOB
• VBG:
•
•
•
•
pH 7.23
pCO2 75
HCO3 28
BE 1
• Transferred to SCH PICU via NETS - CPAP
Observation chart
Take-home messages
• Indications & contraindications for bronchiolitis
• Notify Paediatrician if starting HHFNC oxygen therapy
• Starting prescription:
• Flow 1L/kg/min
• FiO2 40%
• If no improvement within 15 minutes, titrate flow and FiO2
• If no improvement within 60 minutes, consider diagnosis, complications
and escalation of care. NOTIFY senior medical officer
• Weaning of HHFNC Oxygen:
• First FiO2
• Second flow
• Review regularly
0 mins
HHFNC Oxygen Therapy Commenced in infants with bronchiolitis or children with
moderate to severe respiratory distress
1. Who have failed to respond to low flow oxygen and
2. AFTER senior ED/Paediatric Medical Officer review
15 mins
Commence at 1L/kg/min Flow and 40% FiO2
AFTER 15mins if no clinical improvement
Review by Senior Paediatric Medical Officer
Titrate up to 2L/kg/min to a maximum of 25 L/min
Titrate FiO2 up or down to maintain SpO2 between 92-98%
60 mins
Review by Senior Paediatric Medical Officer
Clinically stable or improving
continue to monitor and document
observations hourly
4 hourly review by Senior Medical
Officer / Paediatrician
If clinically stable after 24hrs of
HHFNC therapy ongoing medical
review should occur 4-8 hourly
If clinical state is improving
consider weaning.
1. First decrease FiO2 to maintain
SpO2 > 92%
2. Second decrease flow rate by half
Clinically Unstable
If no improvement after 60 mins,
deterioration, or unable to maintain
saturations above 92% at a maximum
of 60% FiO2 progress to
Senior Medical / Paediatrician
review and local escalation
procedures
If clinical state is deteriorating
escalate as per Local CERS and
contact NETS 1300 36 2500 for
transfer to Tertiary Facility
Consider intubation
HHFNC Oxygen Therapy should not exceed 2L/kg/min or a
maximum of 25 L/min