High Flow Nasal Oxygen and Endoscopy

apnoea endoscopy high flow obstruction oxygen sedation ventilation Nov 14, 2024

Go with the flow – the wonders of high flow nasal oxygen for endoscopy 🌬️👃

Deep sedation to facilitate endoscopy presents all sorts of challenges:

❗ Airway obstruction from the scope

❗ Anaesthesia-induced upper airway collapse

❗ Respiratory depression

❗ Lung compression due to gas insufflation

...just to name a few!

Hypoxaemia is one of the most common adverse events occurring during sedation, happening in 26-85% of cases. 🩺 Older, obese, or highly comorbid patients are at a particularly high risk, with severe or prolonged hypoxaemia potentially leading to:

💥 Neurological damage

💔 Myocardial ischaemia

💓 Arrhythmias

💀 Cardiac arrest

 

Enter: High Flow Nasal Oxygen Therapy (HFNO)! 💨

But what makes high flow nasal oxygen (HFNO), also known as THRIVE (Transnasal Humidified Rapid-Insufflation Ventilatory Exchange), better than conventional oxygen therapy (COT)? 🤔

Let's break it down:

🌬️ COT: Cool, dry gas – uncomfortable and causes surface dehydration in the upper airway

💨💧 HFNO: Warm, humidified gas – maintains moisture, enhances mucociliary clearance, reduces work of breathing, and is far better tolerated by the patient

 

🌬️ COT: Flow rates between 2-10 litres/min, entrained with room air which dilutes the FiO2

💨💧HFNO: Flows range from 50-100 litres/min, minimising entrainment of room air, allowing for an FiO2 delivery of 95-100%

 

🌬️ COT: Provides no positive airway pressure

💨💧HFNO: High flow rates create a reservoir of oxygen in the upper airway, reducing dead space, increasing CO2 washout, and decreasing atelectasis

One of the biggest benefits of HFNO is that it provides apnoeic oxygenation, preventing desaturation in apnoeic patients for up to 20 minutes! 🕒 Bearing in mind that continuous monitoring and observation is still critical to maintain patient safety. Just because HFNO is in use, doesn’t mean you don’t need to monitor a patient's breathing!

As with any mode of treatment, there are some contraindications to the use of HFNO, such as:

🚫 Nasal obstruction

🚑 Airway trauma (e.g., laryngeal fracture, mucosal tear, tracheal rupture)

⚠️ Known or suspected base of skull fractures

🔥 Close proximity to laser or diathermy (Airway fire risk!!)

🦠 Contagious pulmonary infection (*cough COVID *cough)

🩸 Recent FESS surgery or active epistaxis

🚸 Children under the age of 16

Build Knowledge
Improve Safety

 

References:

Carron, M., Tamburini, E., Safaee Fakhr, B., De Cassai, A., Linassi, F., & Navalesi, P. (2022). High-flow nasal oxygenation during gastrointestinal endoscopy. Systematic review and meta-analysis. BJA open, 4, 100098. https://doi.org/10.1016/j.bjao.2022.100098

 

Cooper, J., Griffiths, B., Ehrenwerth, J. (2018). Safe use of high flow nasal oxygen (HFNO) with special reference to difficult airway management and fire risk. APSF V33(2). https://www.apsf.org/wp-content/uploads/newsletters/2018/3302/APSF3302.pdf

 

Nay, M.A., Fromont, L., Eugene, A., Marcueyy, J.L., Mfam, W.S., Baert, O., Remerand, F., Ravry, C., Auvet, A., Boulain, T. (2021). High-flow nasal oxygenation or standard oxygenation for gastrointestinal endoscopy with sedation in patients at risk of hypoxaemia: a multicentre randomised controlled trial (ODEPHI trial). BJA open. https://doi.org/10.1016/j.bja.2021.03.020

 

 

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