Oxygen Therapy V P Stgeorge

Oxygen Therapy LIMITATIONS FOR PRACTICE: RN who has been instructed in this procedure.

AIM: • To supplement a patient with oxygen safely and effectively. • To reverse hypoxemia.

EXPLANATION: Patients usually require supplementary oxygen if demand is greater than supply, eg haemorrhage, myocardial infarct, cardiac failure or if respiratory function is diminished and gas exchange is inadequate.

DEVICES: Mapleson Circuit and Silicon Self-inflating Bag With O2 Reservoir Connected • These deliver 100% O2 with flow rates of 10-15L/min. • May be used with black, anaesthetic face mask, endotracheal or tracheostomy tube. • It is important to maintain a seal with the mask. • A Geudel airway may help with airway maintenance. • Suitable for short-term use only. • Uses: - Cardiac arrest - Ventilator emergency - Pre-oxygenation prior to suction, intubation, tracheostomy change, extubation - Hyperinflation for chest physiotherapy - Transport of ventilated patient

The St George Hospital ICU Nursing Procedure Manual

Revised August 2003

CIG or Hudson Oxygen Mask (Variable Performance) • Most commonly used device. • The O2 percentage delivered to the patient cannot be controlled. O2 percentage is dependent upon: - the O2 flow rate - mask fit (a tight fitting mask delivers a higher percentage of O2 than a loose mask) - the patient’s inspiratory effort Approximate Oxygen percentages:-

L/min 4 6 8 14

% 35 45 50 65

• Flow rates > 4L/min are recommended to prevent rebreathing of expired CO2. • Humidification may be used with flow rates >6L/min for a prolonged period or if the patient’s secretions are tenacious (see procedure “Humidification”).

Venturi Mask (Fixed Performance) • These are designed to deliver a fixed percentage of O2 (24%, 28%, 35%, 40%, 50%). • Operate according to the Venturi principle. • O2 flowing through a narrow orifice entrains room air at up to 150L/min via vents in the mask connector. • The gas flow and the Venturi valve determine the O2 concentration. • Humidification is not necessary due to the large amounts of room air entrained. • These masks are particularly useful for CAL patients whose stimulus to breathe is controlled by a degree of hypoxia (hypoxic drive) because the mask delivers a fixed percentage of O2.

The St George Hospital ICU Nursing Procedure Manual

Revised August 2003

T-Piece Circuit • Deliver fixed percentage of O2 (according to gas flow rates) via an endotracheal or tracheostomy tube (see procedure “Humidification”). • Deliver variable percentage of O2 via CIG, Hudson or tracheostomy mask.

Nasal Prongs (Variable Performance) • Deliver flow rates of 1-4L/min. • Flow rates >5L/min are not recommended due to drying out of the nasal mucosa. • Inspired O2 will be reduced if the patient mouth breathes. • These are inexpensive and comfortable, allow patient to eat or talk without disrupting oxygen therapy. • Ensure correct position of prongs. Approximate Oxygen percentages:-

L/min 1 2 3 4

% 24 28 32 35

NURSING MANAGEMENT: • Ensure equipment is functioning correctly at beginning of each shift. • Patients requiring oxygen therapy should have their oxygen saturation checked with a pulse oximeter continuously. • Arterial blood gases should be taken as ordered or if there is concern about patient’s condition.

The St George Hospital ICU Nursing Procedure Manual

Revised August 2003