Which equipment would the nurse use to ensure the prescribed rate of oxygen is delivered?

Based on Nicol: Essential Nursing Skills 4E
Adapted by: Mary Nevin BNS(Hons) MSc RGN RNT; November 2014: 

Professor Maggie Nicol BSc(Hons) MSc(Nursing) PGDipEd RN

Nasal cannulae. (From Nicol M, Bavin C, Cronin P, et al. 2012 Essential Nursing Skills, 4th edn. Mosby Elsevier, Edinburgh.)

Oxygen cylinder. (From Nicol M, Bavin C, Cronin P, et al. 2012 Essential Nursing Skills, 4th edn. Mosby Elsevier, Edinburgh.)

Oxygen flow meter set at 2 l/min. (From Nicol M, Bavin C, Cronin P, et al. 2012 Essential Nursing Skills, 4th edn. Mosby Elsevier, Edinburgh.)

Learning Objective

After reading the skill overview, watching the video, following up some of the references/web sites and completing the self-test quiz you should be ready to be assessed in practice in the skill of applying nasal cannulae.

Introduction

Oxygen therapy may be required when a patient is unable to breathe in or use the oxygen that they have and a deficit occurs.  This is usually detected by pulse oximetry when the patient’s oxygen saturations are lower than the accepted normal.  Whilst what is normal may differ slightly from patient to patient, a normally well adult who has no previous chronic respiratory condition should have a normal oxygen saturation greater than 94% on air. In adults with known chronic respiratory conditions, an acceptable oxygen saturation may be 88–92% (British Thoracic Society (BTS) 2008).

When it is established that oxygen therapy is required, it will be prescribed (apart from in some emergency situations) with the amount of oxygen to be delivered recorded as either litres/minute or written as a percentage range (e.g. 92–94%) within which the oxygen saturations should be maintained (Olive 2016).

Oxygen delivery devices fall into two main categories: low flow delivery systems or high flow delivery systems. The use of nasal cannulae to deliver oxygen is an example of a low flow oxygen system. Low flow delivery systems (also known as variable performance systems) deliver oxygen at a low flow rate and provide a variable oxygen concentration to the patient. The oxygen concentration is variable because the patient’s inspiratory flow rate is greater than the flow of oxygen; therefore, the patient draws in air from the atmosphere, which dilutes the concentration of oxygen delivered (McGloin 2008).

Nasal cannulae are narrow flexible tubing with two prongs to deliver oxygen via the nostrils. The small prongs are placed 2 cm into the nostrils; the long tubes go over the ears and under the chin. The woggle is adjusted so that the nasal cannulae fit comfortably and stay in place. The nasal prongs should fit comfortably on the patient (Figure 1). Nasal cannulae may be reused for the same patient, provided they are kept dry and free from dust. They should be disposed of in the clinical waste when no longer required.

The maximum flow rate for nasal cannulae is 4 L/min; a higher flow will cause damage to the nasal mucosa.Nasal cannulae are simple and convenient to use and also allow the patient to drink, eat, and speak comfortably while receiving oxygen therapy (Olive 2016). Some patients report that they feel very claustrophobic wearing an oxygen mask, something they do not report with the use of a cannula. However, if the patient requires a higher flow of oxygen than that deliverable through nasal cannula, or they are continually mouth breathing, a venturi mask should be used.  A venturi mask should also be used in acutely ill adults as this allows for a more controlled delivery of a higher percentage of oxygen (BTS 2008).

As well as ensuring that the oxygen is given at the prescribed flow rate, the nurse must also consider the comfort of the patient. Oxygen therapy via nasal cannulae can cause oral and nasal mucosal drying, along with skin redness or ulceration behind the ears. To prevent damage, the nurse must regularly check the patient's condition and document findings. If there is evidence that the patient's skin is becoming damaged they must act accordingly. The nurse must perform regular mouth care and offer the patient frequent sips of fluid (if appropriate for the patient's condition) in order to prevent the oral mucosa drying and cracking.

Oxygen therapy via nasal cannulae can be delivered from an oxygen cylinder or via a piped source. The oxygen cylinder has a black base with white shoulders and has ‘oxygen’ written on it (Figure 2). For safety purposes, if using an oxygen cylinder, the nurse must ensure that a replacement cylinder is available when the volume indicator gauge shows approximately one quarter full. The nurse must also ensure that patients and visitors are made aware of the dangers of smoking when oxygen is being administered as it is highly flammable. Paraffin or other flammable substances should not be used around the patient due to the fire risk (NPSA 2009).

Preparation and safety

• Explain the procedure to the patient in order to gain consent and cooperation.
• Prepare the patient preoperatively, if oxygen therapy is planned postoperatively.
• Patients and visitors must be made aware of the dangers of smoking when oxygen is being administered, because it is highly flammable.
• Patients must be made aware of the risks of using products such as paraffin containing emollients due to their flammable nature.
• Additional personal protective equipment may be necessary if indicated by the patient’s condition.

Procedure

If you are in the Republic of Ireland please use this skill in conjunction with the advice from PHECC

1. Perform hand hygiene and wear personal protective equipment where necessary. Introduce yourself and explain the procedure to thepatient.  
   Rationale – Explain the procedure to gain the patient's cooperation and consent. 
2. Check the patient’s identity and the prescription. Explain the need for oxygen. 
   Rationale – The National Patient Safety Agency emphasises that oxygen therapy is a medication and therefore must be prescribed, except in respiratory emergency situations (NPSA 2009). In order to ensure that administration of medication is safe the nurse must remember the ‘6 rights’, the right patient, medicine, dose, route, time, and documentation (Griffiths 2013).
3. Turn on the oxygen flow meter and set the centre of the ball to the prescribed rate (Figure 3). This should be no more than 4 L/min (Olive 2016). 
   Rationale – It is important that the flow is set at the rate indicated in order to achieve the prescribed amount of oxygen. Higher flows than 4 L/min will damage the nasal mucosa.
4. Place the small prongs into the patient’s nostrils. The other tubes go over the ears and under the chin. Adjust the woggle so that the nasal cannulae are comfortable and stay in place (Figure 1). 
   Rationale – The nasal prongs should fit comfortably so that the patient does not remove them. Tightly fitting nasal prongs can cause significant patient discomfort and skin redness or ulceration behind the ears.
5. Document the oxygen therapy according to local policy. 
   Rationale – To comply with local policy requirements.
6. Check the patient after a few minutes and continue to observe in accordance with patient’s condition and local policy.
Rationale – Oxygen is prescribed when a patient has a need and therefore the administration of oxygen must be checked to ensure that it is achieving the goal.

Ongoing care, monitoring and support

• Observe the patient’s colour, perfusion and respiratory pattern, rate and depth.
• Offer drinks or mouth washes. Oxygen therapy via nasal cannulae dries the mucous membranes of the mouth and nose. Frequent drinks should be provided (if the patient's condition allows).
• Observe the patient’s nose and ears to ensure there is no redness or pressure ulcers developing.
• Nasal cannulae may be reused for the same patient, provided they are kept dry and free from dust. They should be disposed of in the clinical waste when no longer required.
• If using an oxygen cylinder, ensure that a replacement cylinder is available when the volume indicator gauge shows only one quarter full.

Documentation and reporting

• Document oxygen therapy according to local policy.
• Report any abnormalities or complications so that appropriate interventions can be initiated.

What equipment do you need to deliver oxygen?

What would the nurse monitor frequently to ensure that the prescribed amount of oxygen is being delivered to a patient?

How do we measure oxygen delivery?

Which instrument is used to supplemental oxygen supply?