LOADING AWESOME
HIGH FLOW NASAL OXYGEN
www.propofology.com
Dr. David Lyness
@Gas_Craic
AIRVO/HFNO/APNOX/HEATED/HUMIDIFIED/CPAP
Used when high flow FiO2 is needed such as acute respiratory failure, apnoeic oxygenation (APNOX),
procedures like TOE/BAL/endoscopy etc, palliative settings and post-extubation respiratory distress
LOADING AWESOME
Increasingly popular
Heated, humidified, titratable O2 delivered via large bore nasal cannula
More easily tolerated than conventional CPAP/NIV
Oxygen and air source
Air-oxygen blender = up to FiO2 1.0 at a flow rate of up to 60L/min
Active heated humidifier capable of providing 100% body humidity
Single limb heated inspiratory circuit (avoids heat loss & condensation)
Lightweight, flexible delivery tubing
Adjustable head strap
Soft and flexible nasal prongs
Different brands are available (e.g. Optiflow™)
Air-oxygen blender = up to FiO2 1.0 at a flow rate of up to 60L/min
Active heated humidifier capable of providing 100% body humidity
Single limb heated inspiratory circuit (avoids heat loss & condensation)
Lightweight, flexible delivery tubing
Adjustable head strap
Soft and flexible nasal prongs
Different brands are available (e.g. Optiflow™)
Has Been Used In
- Community-acquired pneumonia- Viral pneumonia (e.g. influenza)
- Acute asthma
- Cardiogenic pulmonary edema
- Pulmonary embolism
- Interstitial pneumonia
- Carbon monoxide poisoning
- Surgical Procedures on the Airway
- Post-op Surgical Patients
- (with chest wall pain like cardiac patients)
- COPD patients, bridging intubation
Importantly, the high flow generates positive pressure and also reduces ventilator dead space by washing out CO2.
Heated humidified gas flow preserves nasal mucosa and is more comfortable allowing high flows and enhanced mucocilliary function.
High flow = constant oxygen delivery even with high inspiratory flows from intense respiration efforts (oxygen dilution reduction)
Nasopharyngeal dead space washout decreases dead space, decreases CO2 rebreathing and provides an oxygen reservoir
Nasopharyngeal dead space washout decreases dead space, decreases CO2 rebreathing and provides an oxygen reservoir
Low levels of PEEP may contribute to alveolar recruitment (decreased dead space), improved compliance and decreased work of breathing
HFNC can generate FiO2 1.0 and PEEP of up to 7.4 cmH20 at 60 L/m
This is reduced at lower flow rates and if the nasal cannulae do not have a snug fit in the nares
More comfortable and better compliance than a face mask
Observational data suggests that HFNC outperform face masks for relieving respiratory distress, Improving oxygenation and ?prevents the need for NIV or intubation
Traditional unheated low-flow (≤ 6 L/min) diffuser humidifiers (“bubblers”) are much less effective
More comfortable and better compliance than a face mask
Observational data suggests that HFNC outperform face masks for relieving respiratory distress, Improving oxygenation and ?prevents the need for NIV or intubation
Traditional unheated low-flow (≤ 6 L/min) diffuser humidifiers (“bubblers”) are much less effective
PEEP drops to ~2 cmH20 when the patient’s mouth is open + PEEP is variable and not measurable
More costly and requires more technology than standard nasal cannula - but less ££ than I&V!
Critically ill patients may not be perceived as being so sick if they only have nasal cannulae on.
More costly and requires more technology than standard nasal cannula - but less ££ than I&V!
Critically ill patients may not be perceived as being so sick if they only have nasal cannulae on.
Caution in:
EpistaxisBase of skull fracture
Surgery to nose
Surgery to airway
Nasal obstruction
Nasal obstruction
A case series of 25 patients with difficult airways undergoing general anaesthesia for hypopharyngeal or laryngotracheal surgery had mean apnoea times of 14 minutes without desaturation (i.e. SaO2 >90%)
The FLORALI study = patients with acute hypoxaemic respiratory failure and without hypercapnia, treatment with high-flow nasal oxygen, standard face mask oxygen, or non-invasive ventilation did not result in a significantly different intubation rates.
(Pateal et al, 2015; THRIVE study)
Failure of HFNC might cause delayed intubation and worse clinical outcomes in patients with respiratory failure (Kang et al, 2015)
The FLORALI study = patients with acute hypoxaemic respiratory failure and without hypercapnia, treatment with high-flow nasal oxygen, standard face mask oxygen, or non-invasive ventilation did not result in a significantly different intubation rates.
There was a significant difference in favour of high-flow nasal oxygen in 90 day mortality (Frat et al, 2015; FLORALI study)
http://lifeinthefastlane.com/ccc/high-flow-nasal-cannula/
A controversial issue is when to START HFNO. It seems to be used in an escalation pathway eg:)
Room Air > Nasal Specs > Face Mask Oxygen > High Flow Face Mask/NRM > HFNO > NIV/CPAP > Intubation
