The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [362]
Legal and professional issues
Competencies
Nursing staff must be trained to adequately administer oxygen therapy and their competency assessed. They should check and document that a device is being used appropriately and the flow is as prescribed and appropriate for the patient’s needs. Nursing and physiotherapy staff may assess patients, initiate and monitor oxygen delivery systems within the prescribed parameters, except in emergencies when oxygen should be given first and documented later (NPSA 2009).
Preprocedural considerations
Before commencing oxygen therapy, it is essential that it should be prescribed. This should be in the form of parameters, for example 28–40% to keep saturations (sats) >92%. This will allow nursing staff to alter the oxygen setting to achieve the target saturations without requiring a change to the prescription on each occasion, as well as individualizing treatment to meet the patient’s needs. The only exception to this situation is during immediate management of critical illness or emergency situations when oxygen should be given irrespective of it being formally prescribed (O’Driscoll et al. 2008). Regular pulse oximetry monitoring must be available in all clinical environments where oxygen may be administered. Oxygen therapy will need to be adjusted to achieve target saturations rather than giving a fixed dose to all patients with the same disease. Nurses can make these adjustments without requiring a change to the prescription on each occasion. Most oxygen therapy will be from nasal cannulas rather than masks and will not be given to patients who are not hypoxaemic (except during critical illness).
Equipment
Oxygen is an odourless, tasteless, colourless, transparent gas that is slightly heavier than air. Oxygen supports combustion so there is always a danger of fire when oxygen is being used. The following safety measures should be remembered.
Oil or grease around oxygen connections should be avoided.
Alcohol, ether and other inflammatory liquids should be used with caution in the vicinity of oxygen.
No electrical device must be used in or near an oxygen tent.
Oxygen cylinders should be kept secure in an upright position and away from heat.
There must be no smoking in the vicinity of oxygen.
A fire extinguisher should be readily available.
Care should be taken with high concentrations of oxygen when using the defibrillator in a cardiorespiratory arrest, or during elective cardioversion.
All oxygen delivery systems should be checked at least once per day. Care should be taken to avoid interruption of oxygen therapy in situations including ambulation or transport for procedures.
Oxygen delivery
Any oxygen delivery system will include these basic components.
Oxygen supply, from either a piped supply or a portable cylinder. All medical gas cylinders have to conform to a standardized colour coding: oxygen cylinders are black with a white shoulder and are labelled ‘Oxygen’ or ‘O2’. Since 2004, small portable oxygen cylinders have been in use: these are totally white and are a C-size cylinder.
A reduction gauge: to reduce the pressure to atmospheric pressure.
Flowmeter: a device that controls the flow of oxygen in litres per minute.
Tubing: disposable tubing of varying diameter and length.
Mechanism for delivery: a mask or nasal cannulas.
Humidifier: to warm and moisten the oxygen before administration.
Water trap if humidifier in use.
Nasal cannulas
Nasal cannulas (Figure 10.3) consist of two plastic prongs that are inserted inside the anterior nares and supported on a light frame. Advantages to the patient are that they may seem less claustrophobic and do not interfere with eating, drinking and communication (Fell and Boehm 1998). Nasal cannulas provide an alternative to a mask, but can be used only where the patient requires a low percentage of oxygen and are usually used with flow rates of 1–4 litres of oxygen per minute and provide approximately 28–35% oxygen (Table 10.1). They cannot be attached satisfactorily to an external