- Main types of oxygen therapy
- 1. Low flow systems
- 2. High flow systems
- 3. Non-invasive ventilation
- What is it for
- Care when using at home
Oxygen therapy consists of administering more oxygen than is found in the normal environment and aims to ensure the oxygenation of body tissues. Some conditions can lead to a reduction in the supply of oxygen to the lungs and tissues, as occurs in chronic obstructive pulmonary disease, known as COPD, asthma attack, sleep apnea and pneumonia and therefore, in these cases, oxygen therapy may be necessary.
This therapy is indicated by a general practitioner or pulmonologist after verifying a low level of oxygen in the blood, by performing arterial blood gases, which is a blood test collected from the wrist artery, and pulse oximetry, which is done by observation of oxygen saturation and must be above 90%. Find out more about how pulse oximetry is performed.
The type of oxygen therapy depends on the degree of a person's respiratory distress and the signs of hypoxia, and the use of a nasal catheter, face mask or Venturi may be recommended. In some cases, CPAP may be indicated to facilitate the entry of oxygen into the airways.
Main types of oxygen therapy
There are several types of oxygen therapy that are classified according to the oxygen concentrations that are released, and the doctor will recommend the type according to the person's needs, as well as the degree of respiratory distress and whether the person shows signs of hypoxia, like purplish mouth and fingers, cold sweat and mental confusion. Thus, the main types of oxygen therapy can be:
1. Low flow systems
This type of oxygen therapy is recommended for people who do not need a large amount of oxygen and through these systems it is possible to supply oxygen to the airways in a flow of up to 8 liters per minute or with a FiO2, called fraction of inspired oxygen, from 60%. This means that of the total air that the person will inhale, 60% will be oxygen.
The most used devices in this type are:
- Nasal catheter: it is a plastic tube with two air vents that must be placed in the nostrils and, on average, serve to offer oxygen at 2 liters per minute; Nasal cannula or eyeglass catheter: it is constituted as a small thin tube with two holes in its end and it is introduced into the nasal cavity at a distance equivalent to the length between the nose and the ear and is capable of offering oxygen up to 8 liters per minute; Facial mask: consists of a plastic mask that must be placed over the mouth and nose and works to provide oxygen in higher flows than the catheters and nasal cannulas, in addition to serving for people who breathe more through the mouth, for example; Mask with reservoir: it is a mask with an inflatable bag attached and capable of storing up to 1 liter of oxygen. There are models of masks with reservoirs, called non-rebreathing masks, which have a valve that prevents the person from breathing in carbon dioxide; Tracheostomy mask: equivalent to a specific type of oxygen mask for people who have a tracheostomy, which is a cannula inserted into the trachea for breathing.
In addition, in order for oxygen to be absorbed by the lungs properly, it is important that the person does not have any obstructions or secretions in the nose and also, to avoid drying out the airway mucosa, it is necessary to use humidification when the oxygen flow is above of 4 liters per minute.
2. High flow systems
High flow systems are capable of providing a high concentration of oxygen, above what a person is able to inhale and is indicated in more severe cases, in situations of hypoxia caused by respiratory failure, pulmonary emphysema, acute lung edema or pneumonia. See more what is hypoxia and possible sequelae if left untreated.
The Venturi mask is the most common way of this type of oxygen therapy, as it has different adapters that serve to offer exact and different oxygen levels, according to the color. For example, the pink adapter offers 40% oxygen in an amount of 15 liters per minute. This mask has holes that allow the exhaled air to escape, which contains carbon dioxide, and requires humidification to avoid drying out the airways.
3. Non-invasive ventilation
Noninvasive ventilation, also known as NIV, consists of a ventilatory support that uses positive pressure to facilitate the entry of oxygen into the airways. This technique is indicated by the pulmonologist and can be performed by a nurse or physiotherapist on adult people with respiratory distress and who have a respiratory rate above 25 breaths per minute or oxygen saturation below 90%.
Unlike other types, this technique is not used to provide extra oxygen, but it serves to facilitate breathing by reopening the pulmonary alveoli, improving gas exchange and decreasing respiratory effort and is recommended for people with sleep apnea and who have diseases cardiorespiratory.
In addition, there are several types of NIV masks that can be used at home and vary according to the size of the face and the adaptation of each person, with CPAP being the most common type. Check out more about what CPAP is and how to use it.
What is it for
Oxygen therapy is recommended by a doctor to increase the availability of oxygen in the lungs and tissues of the body, reducing the negative effects of hypoxia, and should be done when the person has oxygen saturation below 90%, partial pressure of oxygen, or PaO2, less than 60 mmHg, or when conditions such as:
- Acute or chronic respiratory failure; Chronic obstructive pulmonary disease; Pulmonary emphysema; Asthma attack; Carbon monoxide poisoning; Obstructive sleep apnea; Cyanide poisoning; Post-anesthetic recovery; Cardiorespiratory arrest.
This type of therapy is also indicated in cases of acute myocardial infarction and unstable angina pectoris, since the oxygen supply can decrease the signs of hypoxia, caused by the interrupted blood flow, increasing the oxygen levels in the blood and, consequently, in the alveoli of the lung.
Care when using at home
In some cases, people who have a chronic respiratory disease, such as COPD, need to use oxygen support for 24 hours a day and therefore, oxygen therapy can be used at home. This therapy is done at home through a nasal catheter, placed in the nostrils, and oxygen is offered from a cylinder, which is a metal container where oxygen is stored and only the amount prescribed by the doctor should be administered.
The oxygen cylinders are made available by specific SUS programs or can be rented from medical-hospital products companies and can also be transported through a support with wheels and can be taken to different locations. However, when using oxygen cylinders, some precautions are necessary, such as not smoking while using oxygen, keeping the cylinder away from any flame and protected from the sun.
Also, the person who uses oxygen at home needs to have access to pulse oximetry devices to check the saturation and in case the person presents signs such as purple lips and fingers, dizziness and fainting, a hospital should be sought immediately, as may have low blood oxygen.
