OXYGEN THERAPY

Indications for O2 Administration
–    Respiratory Compromise – i.e.: cyanosis, partially obstructed airway, tachypnoea
–    Cardiac Compromise – i.e.: chest pain, shock
–    Neurological deficits – i.e.: stroke, spinal injuries

Prescribing O2

•    Several ways of prescribing oxygen amount
•    Flow per minute (L/min)
•    Percentage (%)
•    FiO2

Nasal Cannula
Nasal Cannula

 

Indication:
–    To patient spontaneously breathing, with decreasing level of PaO2.
–    In state of anxiety, without the need of high oxygen concentration
–    O2 flow up to 4 L/min

 

Advantages:
–  Safe and simple
–    Easy fixation.
–    Facilitate verbal communication.
–    Possibility for performing mouth care.
–  Comfortable, allows patient to eat and drink
Disadvantage:
•    Can’t deliver concentrations higher
than 40%;
•    Can’t be used in complete nasal obstruction.
•    May cause headaches or dry mucous membranes; can remove easily.
Nursing care principle:
•    Avoid applying it too tightly, which can result in excess pressure on facial structures as well as cannula occlusion.

Medium Concentration Face Masks

Medium Concentration Face Masks

•    Hudson’ / MC masks
•    O2 flow rate must be at least 5 l/min
•    Amount of O2 received is dependent on the patient’s rate and depth of breathing,
•    Not possible to know exactly how much O2 is being delivered
•    Poor humidification
•    Disposable

Fixed Concentration Masks ‘Venturi’
Fixed Concentration Masks Venturi

Fixed Concentration Masks
•    ‘Venturi’
•    O2 has to be at minimum recommended flow rate to achieve correct percentage of O2
•    O2 flow from 4 – 15 l/min
•    O2 delivery up to 60%
•    Bernoulli principle – port size of valve ensures the correct proportions of O2 and entrained air are mixed to obtain a fixed O2 concentration
•    Able to increase flow rate without altering percentage of O2

Venturi mask
•    Venturi mask mix a fixed flow of oxygen with a high but variable flow of air to produce a constant oxygen concentration.
•    Oxygen enters via jet (restricted opening) at high velocity, room air also enters and mixes with the oxygen at this site. The higher the velocity (smaller the opening), the more room air is drawn.

Reservoir Masks

Reservoir Masks
Reservoir Masks
•     ‘Non-rebreath mask’
•    O2 delivered between 60 – 85%
•    O2 flow must be 15 litres/min
•    Bag should be filled with O2 by at least 2/3 before applying to patient
•    High FiO2 delivered because of reservoir which provides increased volume of O2

Tracheostomy tube

Tracheostomy tube
Indication:
–    Failing to wean the patient from M.V.
–    When airway blocked and intubation is impossible.
–    When suspected edema of the larynx.
–    When an intubation endangers to the patient (cervical spine #).
Advantage
–    No danger in damaging the vocal cord
–    Ability to verbal communication.
–    Ability to perform an efficient mouth care program.

Disadvantage
–    Risk for bleeding and emphysema.
–    Risk of tracheal damage in prolonged use.
–    Risk of developing granulomas in operation incisions.
–    Increase risk of displaced canula in the first 24hr.

CPAP mask


•    This system allows the spontaneously breathing patient to receive continuous positive airway pressure (CPAP) with or without an artificial airway.

Advantages:
–    Noninvasively improves arterial oxygenation
–    by increasing functional residual capacity;
–    Allows the patient to avoid intubation;
–    allows the patient to talk and cough without interrupting positive pressure.

Disadvantages
•    Requires a tight fit, which may cause discomfort; interferes with eating and talking; heightened
•    Risk of aspiration if the patient vomits.
•    Increased risk of pneumothorax, diminished cardiac output, and gastric distention;

Risks of Oxygen Therapy


–    O2 toxicity:

–  Very high levels lead to CNS toxicity and
seizures
–   Lower levels (FiO2 > 60%) and longer exposure (48hr):   capillary damage, leak and
pulmonary fibrosis
–   PaO2 >150 can cause retrolental fibroplasia
–  FiO2 35 to 40% can be safely tolerated indefinitely

Clinical manifestation of O2 Toxicity


– Restlessness, chest pain, dyspnea and cyanosis.
– Nausea, anorexia and vomiting
CO2 narcosis:
–   PaCO2 may increase severely to cause respiratory     acidosis and coma.
Nursing Alert
Because hypoxemia stimulates respiration in the pts with sever COPD, increase the oxygen flow level to a high rate may greatly raise the patient blood oxygen level. At the same time this will suppress the respiratory drive, causing increase retention of CO2 and CO2 narcosis.
So oxygen given with low concentration

Indications for Humidification


•    Room Air is 50% humidified
•    O2 is 0 % humidified
•    Dehydration of the respiratory tract by O2 can cause epithelial damage
•    Resulting in destruction of cilia and damage to mucous glands
•    Important to humidify inspired gases
•    O2 of at least 40% or above should be humidified
•    Cold / Hot water humdification
•    Saline nebulisers can be used as alternative

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