This document discusses high flow nasal cannula (HFNC) and humidification. It provides an overview of HFNC, including how it works and key points. HFNC can deliver high levels of oxygen and is well tolerated by patients. It has several benefits over traditional oxygen masks, including better washout of dead space and more consistent oxygen delivery. The document reviews indications, contraindications and complications of HFNC. It also discusses evidence on using HFNC to prevent intubation in respiratory failure, as peri-intubation support, and for post-extubation therapy. Risks, cleaning and questions around HFNC are also addressed.

1. Nick Dalmon
Staff Nurse
Intensive Care, William Harvey Hospital
High Flow Nasal Cannula and
Humidification

2.  Risks
 Respiratory failure
 Preventing intubation
 Peri-intubation
 Post extubation therapy
 Questions
 What is HFNC
 Key Points
 Indications
 Contraindications
 Complications
 Positive effects
Overview

3. •Oxygen and air source
•Air-oxygen blender generates 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 and
condensation)
•Lightweight, flexible delivery tubing
•Adjustable head strap
•Soft and flexible nasal prongs
•Different brands are available (e.g.
Optiflow™)
High Flow Nasal Cannula (Optiflow)

4.  The amount of oxygen a patient gets
depends on their inspiratory flow rate.
 Masks do not deliver consistent levels
of Oxygen, HFNC does.
 Dead space is washed out (Möller et
al, 2015)
 Its not a reliable form of PEEP!!
 Mouth closed ~ 7cmH2O
 Mouth open ~ 2! (Ritchie et al, 2011)
Key Points

5. Hypoxic respiratory failure, e.g.:
 •Community-acquired pneumonia
 •Viral pneumonia (e.g. influenza)
 •Acute asthma
 •Cardiogenic pulmonary odema
 •Pulmonary embolism
 •Interstitial pneumonia
 •Carbon monoxide poisoning
Need for high FiO2 oxygen delivery
in settings such as:
 •Intubation (pre-oxygenation and
apnoeic oxygenation)
 •Post-extubation respiratory
distress
 •Do-not-intubate/ palliative
settings
 •Post-cardiac surgery
 •Oxygen supply during invasive
procedures, e.g: TOE, upper GI
endoscopy
Indications

6. •Epistaxis
•Base of skull
fracture
•Surgery to the nose
or upper aero-
digestive tract
•Nasal obstruction;
e.g. nasal fracture,
tenacious secretions,
tumour
Contraindications

7.  •Local trauma, discomfort and
pressure areas
 •Epistaxis
 •Gastric distension
 •Blocked cannulae due to secretions
Complications

8.  High flow washes out carbon dioxide in
anatomical dead space. I.e. the patient
actually gets the oxygen you are giving
them!!
 Because gas is generally warmed to 37°C
and completely humidified, mucociliary
functions remain good and little
discomfort is reported.
 Compliance is increased as patients can
talk, eat and drink whilst on HFNC
 Improved mouth care
 Less input from nursing staff!!!
Positive effects

9.  He is doing ok on that, lets not
intubate……
 In patients who are acutely unwell
with high oxygen/flow rates, there
should be a two hour limit on HFNC
trial.
 It should NOT delay intubation.
 Failure of HFNC might cause delayed
intubation and worse clinical
outcomes in patients with respiratory
failure (Kang et al, 2015)
Risks

10.  Gold standard for Type 2 is still BiPAP
 No big studies yet
 One small study compared treating
patients in acute respiratory failure
with facemasks and HFNC
 They found that the HFNC improved
the patients PaO2 and was associated
with a lower respiratory rate (Roca et
al, 2013)
Respiratory failure (Type 1)

11.  A second study evaluated the efficiency, safety
and outcome of high flow nasal cannula
oxygen (HFNC) in ICU patients with acute
respiratory failure.
 HFNC significantly reduced the respiratory
rate, heart rate and increased pulse oxymetry.
 These improvements were observed as early
as 15 min after the beginning of HFNC for
respiratory rate and pulse oxymetry. PaO2 and
PaO2/FiO2 increased significantly after 1 h
HFNC in comparison with baseline (Sztrymf et
al, 2011).
Respiratory failure continued

12.  One study compared standard therapy,
NIV and HFNC in patients with type 1
respiratory failure
 They found the intubation rate was lower
in the HFNC group (38% of patients
compared with 47% in the standard and
50% in the NIV group) but this was not
statistically significant.
 It did show an improvement in ventilator
free days and 90 day mortality (Frat et al,
2015).
Preventing intubation

13.  A study which looked at respiratory
failure in do not intubate patients
treated with HFNC first and escalated
to NIV if HFNC failed
 The study showed that HFNC was
effective in increasing oxygen
saturations and lowered respiratory
rate.
 9 of the 50 (18%) patients recruited
had to be escalated to NIV
Preventing intubation

14.  Preoxygenation and apnoeic
oxygenation
Compared to HFFM (high flow face
mask), HFNC as a preoxygenation
device did not reduce the lowest
level of desaturation in an RCT
(Vour’ch et al, 2015 – PREOXYFLOW
trial)
Peri-intubation

15.  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%) (Pateal
et al, 2015; THRIVE study)
Peri-intubation continued

16.  Evidence is coming through that we
should be extubating onto HFNC in all
patients
 Compared to facemask, in low risk
patients, at the same FiO2 as when
ventilated, there were less episodes of
desaturation (75% to 40%) and
reintubation rates were reduced (21%
to 4%). (Maggiore et al, 2014)
Post extubation therapy

17.  A second study compared high and
low risk patients extubated onto
“conventional oxygen therapy” and
optiflow.
 Compared to the conventional
therapy patients experienced lower
rates of respiratory failure leading to
reintubation ( 12% to 5%) (Hernández
et al, 2016)
Post extubation therapy continued

18.  We all know how to clean an Optiflow,
hopefully!!
 What about weaning? 2hours on 2
hours off……
 Do you need a new set?
 When you do
 When you don’t……
Cleaning

19.  A meta analysis published in late 2017
showed that HFNC is supreior to
standard oxygen therapy in
preventing intubation
 It also showed no diffrence in
intubation rates between HFNC and
NIV
 The recommend further RCT’s (Zhao
et al, 2017)
STOP THE PRESSES!!

20.  What HFNC is
 What its good for
 What its not good for
 Should HFNC be our first line treatment for Type 1 RF?
 Good or bad for peri-intubation?
 Should we extubate onto HFNC routinely?
Conclusion

21. Questions & Discussion

22. References
• Kang, B.J., Koh, Y., Lim, CM. et al. Intensive Care Med (2015) 41: 623.
https://doi.org/10.1007/s00134-015-3693-5
• Patel A, Nouraei SA. Transnasal Humidified Rapid-Insufflation Ventilatory Exchange
(THRIVE): a physiological method of increasing apnoea time in patients with difficult
airways. Anaesthesia. 2015;70:(3)323-9.
• Vourc’h, M., Asfar, P., Volteau, C. et al. Intensive Care Med (2015) 41: 1538.
https://doi.org/10.1007/s00134-015-3796-z
• Möller W, Celik G, Feng S, et al. Nasal high flow clears anatomical dead space in upper
airway models. J Appl Physiol 2015;118(12):1525–1532.
• Ritchie JE, Williams AB, Gerard C, Hockey H. Evaluation of a humidified nasal high-flow
oxygen system, using oxygraphy, capnography and measurement of upper airway
pressures. Anaesth Intensive Care 2011;39(6):1103–1110.
• Maggiore SM, Idone FA, Vaschetto R, et al. Nasal high-flow versus Venturi mask
oxygen therapy after extubation. Effects on oxygenation, comfort, and clinical
outcome. Am J Respir Crit Care Med 2014;190(3):282–288.
• Hernández G, Vaquero C, González P, et al. Effect of Postextubation High-Flow Nasal
Cannula vs Conventional Oxygen Therapy on Reintubation in Low-Risk Patients: A
Randomized Clinical Trial. JAMA 2016;315(13):1354–1361.

23. • Roca O, Pérez-Terán P, Masclans JR, et al. Patients with New
York Heart Association class III heart failure may benefit
with high flow nasal cannula supportive therapy: high flow
nasal cannula in heart failure. J Crit Care 2013;28(5):741–
746.
• Sztrymf B, Messika J, Bertrand F, et al. Beneficial effects of
humidified high flow nasal oxygen in critical care patients: a
prospective pilot study. Intensive Care Med
2011;37(11):1780–1786.
• Frat J-P, Thille AW, Mercat A, et al. High-flow oxygen
through nasal cannula in acute hypoxemic respiratory
failure. N Engl J Med 2015;372(23):2185–2196.