Description[edit | edit source]Oxygen therapy has been in use for
centuries. Oxygen)(O2) is gas used as a drug/medication and a such should be prescribed and administered in the right manner with regards to presenting indications for it's use[1]; which is always in the case of hypoxaemia[2]. It has side effects and specific
risks, but, with objective monitoring and administration, it is a potent therapy for the patient with respiratory condition[3]. Oxygen is an expensive medication; thus, it's indication must be met before use. Show
Indications For Oxygen Therapy[edit | edit source]Oxygen is rarely indicated for any other reason than Hypoxaemia[4].
Other indications include:
Risks Of Oxygen Therapy[edit | edit source]1. Depression of ventilation: It is seen in COPD patients with chronic carbondioxide (CO2)retention who have hypoxic respiratory drive to breath[9]. Increased arterial tension to normal can lose the hypercapnoeic stimulus to maintain ventilation resulting in hypoventilation in these patients[10]. 2. Hyperbaric oxygen toxicity: Long term hyperbaric O2 therapy can lead to pulmonary, optic and central nervous system toxicity[11]. 3. Fire hazard: Oxygen enhance combustion of other fuels. Least level of supplemental oxygen (FiO2 greater than the 21% oxygen in ambient air) should be administratered during laser bronchoscopy to avoid intratracheal ignition[12]. 4. Absorption atelectasis: Given only pure oxygen results in the collapse of the dependent part of the lungs as it quickly taken up from the alveoli. It is also a risk in general anaesthesia induction[7] 5. Retinopathy of prematurity (ROP): It usually occur in low birth weight, very premature infant. That is why in preterm infants, 50-80 mmHg PaO2 is recommended in infants receiving oxygen[13] 6. Bacterial contamination associated with certain nebulization and humidification systems is a possible hazard[14]. 7. Oxygen therapy is contrindicated in patients suffering from paraquat poisoning[15] 8. Pulmonary toxicity: Patients exposed to high oxygen levels for a prolonged period of time have lung damage[16]. The extent of lung damage is dependent on FiO2 and duration of exposure. It is due to intracellular free radicals (such as superoxide, activated hydroxyl ions, singlet O2 and hydrogen peroxide) formed which can damage alveolar-capillary membrane. It starts with increased permeability of the capillaries with resultant edema, thickened membranes and finally to pulmonary fibrosis. Care should be taken in the use of oxygen in patients receiving bleomycin or have previously used bleomycin [17]. [edit | edit source]
Delivery Devices for Oxygen Therapy[edit | edit source]The oxygen delivery devices are grouped into two: Low flow oxygen delivery system High flow oxygen delivery system Low flow oxygen delivery systems are those that the exact fraction of oxygen in the inspired air (FiO2) will be based on the patient's anatomic reservoir and minute ventilation. They are:
High flow oxygen delivery systems[20] deliver a prescribed gas mixture (either high or low) at flow rates that exceed patient demand.
Oxygen Storage and Source[edit | edit source]Vacuum insulated evaporator (VIE): When a gas becomes liquid form, it occupies a much smaller volume. Therefore, a large amount of oxygen can be stored in the form of liquid. A VIE is a container designed to store liquid oxygen. The VIE system is used in large hospitals which have a pipeline system. It is the most economical way to store and supply oxygen.[19][20][4] Oxygen cylinders: It is expensive, cumbersome, and often unreliable. It usually serve as a backup in large hospitals and used mainly in out of hospital settings. Oxygen concentrators: It draws air from the atmosphere and extracts nitrogen leaving upto 90-96% concentration of oxygen using zeolite molecular sieve. It is safe, reliable, and cost efficient source of oxygen, and more convenient than oxygen cylinder. It is important to have a backup source of oxygen(Oxygen cylinder), as it needs continuous power source and regular maintenance. Central piped oxygen: oxygen is distributed via copper pipes circulating from a central source, that is situated outside the building. The source may be liquid oxygen, high-pressure gaseous oxygen cylinders, a large oxygen concentrator or a combination. It has the advantage of reduced risk of fire and obviates handling and transporting heavy cylinders between hospital wards. The high installment and maintenance cost is it’s daunting factor. Resources[edit | edit source]References[edit | edit source]
When should an EMS professional use oxygen humidification on a patient?When should an EMS professional use oxygen humidification on a patient? When the patient will receive oxygen for longer than 1 hour. Oxygen humidifiers should be filled with sterile water.
How often are humidified oxygen systems replaced to prevent infection?Heated, high flow oxygen system (i.e. Optiflow®) wire circuit and humidifier chamber are not required to be changed regularly. However, the interface of these systems should be replaced weekly. For home care clients, change items only when visibly soiled. 2.4.
What is the maximum flow rate that you would administered by nasal cannula?A traditional nasal cannula can only effectively provide only up to 4 to 6 liters per minute of supplemental oxygen. This equates to a FiO2 of approximately 0.37 to 0.45.
For which of the following patients would a nasal cannula be the most appropriate oxygen delivery device?The nasal cannula is most appropriate for patients experiencing minimal respiratory distress. Like the nasal cannula, the face mask mixes oxygen with room air, but it can provide higher oxygen concentrations (35% to 60%) and higher flow rates (5 to 10 liters/minute).
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