Oxygen Therapy
What is oxygen therapy?
Oxygen is necessary for the survival and effective functioning of all body tissues. When body tissues are not receiving enough oxygen, we have to supplement extra oxygen.
The administration of extra oxygen at higher concentration than that in the room air (more than 21%) to treat or prevent hypoxia (decreased oxygen level in blood) is called oxygen therapy.
Like other drugs Oxygen therapy requires a doctor’s prescription as it can produce serious side effects.
What are the main goals of oxygen therapy?
Major goals of oxygen therapy are:
- Treat hypoxia (decreased oxygen level in blood).
- Decreased work of breathing
- Decreased myocardial work(reduce heart muscle contraction)
What are the indications for oxygen therapy?
- Acute respiratory failure.
- Acute myocardial infarction (blood flow blockage in hear muscle)
- Cardiac failure (heart fails to pump blood)
- Shock (sudden drop in blood flow through the body)
- Hyper metabolic state induced by trauma, burns or sepsis
- Anaemia ( Lack of red blood cells in blood plasma)
- Cyanide poisoning (toxic has prevents absorption of oxygen)
- During CPR (cardiopulmonary resuscitation)
- During anaesthesia for surgery.
What are the sources of oxygen?
1. Oxygen cylinder
- It is delivered with a protective cap to avoid accidental force against the cylinder outlet.
- A regulator is used to release oxygen safety and at a desirable rate.
- Amount of oxygen in the tank is shown in a reduction gauge.
- The oxygen is regulated and control by a flow meter in liter in meter.
- Humidifier is used to moisten the oxygen to prevent dryness of mucous membranes of therespiratory tract.
2. Oxygen through wall outlets from a central source:
- Through a pipeline from a central source oxygen is supplied.
- Only flow meter and a humidifier are required.
3. Oxygen Concentrator
- Operates on electricity.
Extracts oxygen from air, concentrate it and delivers.
How oxygen is administrated? What are the oxygen delivery devices?
Oxygen is supplied through oxygen delivery systems. Different types are available. We have to choose the type depending on the condition of the patient.
- Low flow devices: Delivers flow rate of 25 – 30 L/min.
- High flow devices: Delivers flow rate more than 30L/min.
What are Low flow devices?
Low flow devices are:
- Nasal cannula,
- Nasal catheter,
- Transtracheal oxygen catheter,
- Simple oxygen mask,
- Partial – re breathing mask,
- Non – re breathing mask.
What are High flow devices?
High flow devices are:
- Venturi mask
- Oxygen tent
- Aerosal mask
- Face tent
What is nasal cannula?
It delivers oxygen of 24 – 44% at flow rate of 1- 6 liter/min.
It is well tolerated by the patient
It is easy for patient to eat and communicate.
What is nasal catheter?
It delivers oxygen of 24 – 44% at a flow rate of 1 – 4 L/min.
It should be lubricated with water soluble gel and inserted nasally just above the uvula.
What is Transtracheal oxygen catheter?
The catheter is inserted directly into the trachea through an incision between the 2nd and 3rd
tracheal rings to deliver low rate of 1 – 6 L/min.
What is simple oxygen mask?
It delivers oxygen of 25 – 55 % at flow rate of 6 – 10 L/min.
Patient may find difficult to communicate and eat.
What is partial – re breathing mask?
It delivers oxygen of 35 – 60% at flow rate of 8 – 15 L/min.
The flow must be sufficient to keep the reservoir bag at least one-third to one-half all time.
Only the 1st part of the patient’s exhaled gas enters the reservoir bag. This is the gas that was left in the upper airway from previous inspiration and is therefore high in oxygen and low in carbon.
What is non-re breathing mask?
It delivers oxygen of 75 – 100% at flow rate of 8 – 15 L/min.
The flow must be sufficient to keep reservoir bag at least one-third to one and half full at all time.
One way fluttered valve are located to prevent air entertainment.
What is Venturi mask?
Delivers oxygen of 24 – 48%
Increasing the flow rate on the device will not alter FiO2. Jet size and entrainment port alter FiO2.
The larger the entertainment port, the more air entrained and the lower the FiO2. Likewise, the smaller the entrainment port, the more air entrained and the higher the FiO2.
Larger the jet size, less air entrained and higher the FiO2. Likewise, smaller the jet size more air entrained and lower the FiO2.
What is oxygen tent?
It delivers oxygen of 21 – 50% at flow rate of 15 L/min. Primary used on children with croup or pneumonia.
What is aerosol mask?
It delivers 2% to 100% oxygen at flow rate of 8 – 15 L/min.
What is face tent?
It delivers 40% oxygen at flow rate of 10 – 15L/min.
What are the complications of oxygen therapy?
- Oxygen toxicity
- Depression of ventilation
- Retinopathy of prematurity(Abnormal blood vessel growth in retina of eye)
- Absorption atelectasis ( nitrogen washout in lungs causes lung alveoli collapse)
- Fire hazard.
