Administration of oxygen is an important therapeutic intervention to prevent death from hypoxia due to pneumonia.
The world health organization has recommended the administration of oxygen through a nasopharyngeal catheter , a nasal catheter and nasal tips.
While nasal prongs are said to be safer, catheters are more effective at oxygenating or just as effective.
In a similar study comparing tipped nasopharyngeal catheters, nasopharyngeal catheters were found to be associated with more complications, such as nasal ulceration, nasal bleeding, and increased mucus production.
Due to concerns about the safety of the nasopharyngeal catheter, which is inserted deep into the nasopharynx down to the level of the uvula, some centers have modified the procedure by inserting the catheter midway. This is known as a nasal catheter.
Description of the nasal catheter
The catheter is intended for long-term [long-term] and short-term oxygen therapy. It is made of transparent non-toxic medical polyvinyl chloride.
Ensures regular supply of oxygen. It is easily fixed in the patient’s nostrils by regulating the length of the loop. The thermoplastic material of the nasal teeth is softened by the temperature of the body and does not cause discomfort to the patient.
The edges of the nasal teeth are smooth, have a rounded shape, eliminate the risk of damage to the mucous membrane of the nose. Length of the tube for the connection to the oxygen pipeline 2 m.
The catheter has a flange in the area of the nasal teeth, it simplifies the manipulations with the introduction and extraction of the catheter. The size of the connector complies with international standards and allows connection to any oxygen network.
The administration of oxygen through a catheter inserted into the nose was used in the last war for the treatment of pulmonary edema due to gas poisoning. Introduced by Stokes, it was used with varying results by Douglas, Ryle, Hamil, and Hoover.
In general, the nasal catheter was considered less effective but more comfortable than the Haldane mask. In 1922, I discovered that it was an effective method of delivering oxygen to babies, in whom oxygen consumption and tidal air were small.
Later experience showed that the oxygen concentration in the inspired air could be increased to 30% and that the oxygen content of the arterial blood of pneumonia patients could be raised considerably if 2 liters per minute of oxygen were administered through the catheter.
Clinical oxygen delivery is now being used in many disorders and is being used both at home and in the hospital. This has been made possible by the improved availability of oxygen and the development of simplified equipment for its administration.
In general, it is considered that inhaled air must contain 35 to 55 percent oxygen to produce therapeutic effects.
To achieve these percentages of oxygen in the inhaled air, several methods have been used; namely, the oxygen room, the oxygen tent and the nasal catheter.
The nasal catheter method is a simple means of delivering oxygen, but has been criticized by many for being relatively inefficient.
Comparison of nasal tips with nasal catheters
Efficient, inexpensive and safe methods of delivering oxygen to children with severe pneumonia are needed in developing countries .
The objective is to estimate the frequency of complications when nasal catheters or nasal tips are used for oxygen delivery.
Ninety-nine children between 2 weeks and 5 years of age with hypoxia were randomized to receive oxygen through a nasal catheter (49 children) or nasal barbs (50 children).
There were no differences in the incidence of hypoxemic episodes or in oxygen flow rates between the two groups. Mucus production was more of a problem in the catheter group.
Nasal blockage, intolerance to the method of administration, and nursing effort were generally higher between catheter groups, but these differences were not significant, except in nursing effort, when all age groups were analyzed together.
Oxygen Administration: What’s the Best Option?
Although design plays an important role in the selection of oxygen delivery devices, clinical evaluation and performance ultimately determine which device to select.
Oxygen administration is used routinely in most patients admitted to the emergency room or intensive care unit with respiratory distress.
Indications for oxygen administration include: hypoxemia, increased work of breathing, and hemodynamic failure.
Goal of oxygen therapy
The overall goal of administering oxygen therapy is to maintain adequate tissue oxygenation and minimize cardiopulmonary work.
Signs of inadequate oxygenation include: tachypnea, accessory muscle work, dyspnea, cyanosis, tachycardia, and hypertension.
Oxygen administration can also be used for chronic administration in patients with advanced cardiopulmonary disease and can be administered during diagnostic evaluation or evaluation.
Oxygen supply devices
Currently, there is a wide range of oxygen delivery devices available for use by the respiratory therapist for administration.
The choice of oxygen delivery devices depends on the patient’s oxygen requirement, device efficacy, reliability, ease of therapeutic application, and patient acceptance.
Although design plays an important role in the selection of these devices, clinical evaluation and performance ultimately determine how and which device should be selected.
Oxygen delivery devices range from very simple and inexpensive designs to more complex and expensive designs. Percent oxygen delivery may be inconsistent or accurate depending on the type of delivery device selected.
Oxygen administration can be administered through low-flow or high-flow systems, with or without humidity, and with or without reservoir.
Monitoring the effectiveness of oxygen delivery includes arterial blood gas analysis, oxygen saturation monitoring, and clinical evaluation.
Oxygen can be considered toxic if the percentages are administered in percentages greater than 60% and in the population of patients with chronic carbon dioxide retention it can decrease the impulse of the ventilator and produce life-threatening hypercarbia.
It can also cause absorption atelectasis by flushing nitrogen gas when delivered in high concentrations.
Oxygen delivery devices have historically been classified into three basic types based on their design: low flow, reservoir, and high flow.
Regarding the range of the inspiratory oxygen fraction, oxygen systems can be divided into those indicated for low oxygen (<35%), moderate administration (35% -60%) or high administration (> 60%).
Some devices can provide a wide range of oxygen percentages. When selecting an oxygen delivery device, the respiratory therapist must answer two key questions.
First, how much oxygen can the device deliver? Second, is the inspiratory oxygen fraction consistent or can it vary with changing breathing patterns?
Below is a review of the different oxygen delivery devices, clinical indications, and use:
Low flow delivery
Typical low-flow oxygen systems provide supplemental oxygen often less than the patient’s total minute ventilation.
Because the patient’s minute ventilation exceeds flow, the oxygen delivered by the device will dilute with the ambient air, and therefore the inspired oxygen delivery is less than expected.
Low flow oxygen delivery systems consist of nasal cannula, nasal catheters, and transtracheal catheters.
An inspiratory oxygen fraction (FiO2) of 24-44% in delivery flows ranging from 1-8 liters per minute. The formula is FiO2 = 20% + (4 x flow of liters of oxygen).
Inspiratory oxygen fraction is influenced by respiratory rate, tidal volume, and pathophysiology.
The slower the inspiratory flow, the higher the inspiratory oxygen fraction and the faster the inspiratory flow, the lower the inspiratory oxygen fraction.
Since the percentage of oxygen delivered is highly inconsistent during respiratory distress, a nasal cannula is not recommended for severe acute hypoxemia or patients breathing in a hypoxic unit where a high concentration of oxygen can cause respiratory depression.
A nasal cannula does not use an external oxygen reservoir and relies on the patient’s upper airway as an oxygen reservoir.
A humidification device is recommended for flows greater than four liters to ensure humidification of the dry inspiration gas.
Even with added moisture, flows of 6 to 8 liters per minute can cause a dry nose and bleeding.
The best clinical indications are for patients who have a relatively stable breathing pattern, who require a low percentage of oxygen, who require supplemental oxygen during a surgical or diagnostic procedure or for chronic home care.
A nasal catheter is a soft paste tube with several holes in the tip. It is inserted into a nostril, which must be changed every eight hours.
This device has been replaced by the nasal cannula, but can be used for a patient undergoing an oral or nasal procedure.
Transtracheal catheters deliver oxygen directly to the trachea. There are washing and storage effects that promote gas exchange in addition to providing high-flow oxygen.
High-flow transtrakic catheters can reduce work of breathing and increase carbon dioxide (CO2) removal in the chronic oxygen user.
Transtracheal oxygen therapy improves the efficiency of oxygen delivery by creating an oxygen reservoir in the trachea and larynx.
Consequently, the average oxygen saving amounts to 50% at rest and 30% during exercise.
Transtrakic oxygen reduces dead space ventilation and inspired ventilation in minutes, while slightly increasing alveolar ventilation, which may result in a reduction in the oxygen cost of respiration.
As a result, patients using this device may experience better exercise tolerance and reduced breathlessness .
This delivery device is best used for outpatients and home care patients who require long periods of mobility and are not comfortable using a catheter or nasal cannula.
Reservoir systems incorporate a mechanism to collect and store oxygen during inspiration and exhalation.
Patients draw from the oxygen reservoir whenever their minute ventilation flow exceeds the device delivery flow.
Litter flows of up to eight liters have been reported to adequately oxygenate patients with a high flow requirement.
The reservoir can be located under the nasal cannula or hung as a pendant around the neck of the patient.
The device is aesthetically acceptable to patients and its widespread use in patients requiring chronic oxygen therapy could generate significant financial savings.
Similar to transtrakic oxygen, this device is best used by chronic oxygen users who desire a higher degree of mobility than traditional oxygen systems.
To increase the concretion of delivered oxygen, a mask reservoir is often used. The volume of the mask is approximately 100-300 cm3 depending on the size. It can deliver 40-60% inspired oxygen fraction to 5-10 liters.
The fraction of inspired oxygen is influenced by respiratory rate, tidal volume, and pathology. A flow rate of more than 5 liters should be established to ensure exhaled gas scrubbing and carbon dioxide retention.
The mask is also indicated in patients with nasal irritation or epistaxis. It is also useful for patients who are strictly mouth breathers.
However, the mask can be bothersome, uncomfortable, and confining. It smoothes communication, obstructs coughing and prevents eating.
It can also mask aspiration in the semi-conscious patient. A simple mask must be administered for more than a few hours due to the low humidity delivered and the drying effects of oxygen gas.
This device is best used for short-term emergencies, operative procedures, or for those patients where the nasal cannula is not appropriate.
The non-respiring mask is indicated when an inspired oxygen fraction> 40% is desired and for acute desaturation. It can deliver a fraction of inspired oxygen up to 90% at flow settings greater than 10 liters.
Oxygen flows into the reservoir at 8-15 liters, washing the patient with a high concentration of oxygen. Its main drawback is that the mask must be hermetically sealed on the face, which is uncomfortable and dry.
There is also the risk of carbon dioxide being retained if the mask reservoir bag is allowed to collapse on inspiration. Humidification is difficult with this device, due to the high flow required and the possibility of the humidifier turning off.
This device is best used in acute cardiopulmonary emergencies where a high fraction of inspired oxygen is needed.
Its duration must be less than four hours, secondary to the inadequate supply of humidity and a variable of a fraction of inspired oxygen for patients who require a high percentage of precise oxygen.
High flow delivery
High-flow oxygen delivery systems deliver a given oxygen concentration at a flow equal to or greater than the patient’s inspiratory flow demand.
An air entrainment or mixing system is often used. As long as the delivered flow exceeds the total patient flow, an exact fraction of inspired oxygen can be achieved.
A Venturi mask mixes oxygen with ambient air, creating high-flow enriched oxygen of a desired concentration.
Provides an accurate and constant fraction of inspired oxygen despite varying respiratory rates and tidal volumes.
The fraction of the inspired oxygen delivery setting is typically set to 24, 28, 31, 35, and 40% oxygen.
The Venturi mask is often used when the physician has a concern about carbon dioxide retention or when the respiratory drive is inconsistent.
The addition of humidification is not necessary with this device, secondary to the large amount of environmental carryover that occurs to ensure the exact fraction of inspired oxygen delivered.
The Venturi mask is often used in the chronic obstructive pulmonary disease patient population, where the risk of disabling the patient’s hypoxic drive is of concern.
An aerosol generating device will provide between 21 and 100% inspired oxygen fraction, depending on how it is configured.
The flow is generally set at 10 liters and the desired fraction of inspired oxygen is selected by adjusting a drag collar located on top of the aerosol container.
The humidity device is connected to the flow meter, and a large diameter tube connects it to the patient’s mask.
The wide-gauge tubes and the reservoir bag are placed in-line to act as an oxygen reservoir to ensure that an exact high fraction of inspired oxygen is delivered.
This device adds water content to the patient and can add in the liquefaction of retained secretions.
This oxygen delivery option is ideal for tracheostomy patients because it allows the inspired air to be oxygenated, humidified, and even warmed, if necessary.
They can be attached to a mask, a tracheostomy mask, and even a T-piece.
If the patient’s flow exceeds the total administered flow (carryover in the environment and 10 liters per minute), the patient can retain carbon dioxide and the fraction of inspired oxygen will be lower than desired.
During inhalation, an aerosol mist should be seen coming from the mask or reservoir. To ensure accurate delivery of oxygen through this system, an oxygen analyzer must be used.
This device can be used to ensure a precise oxygen supply and also to maintain the humidification of the artificial airways.
A relatively new oxygen delivery device is the High Flow Nasal Cannula (HFNC) delivery system. Nasal oxygen has been administered in flows ranging from 10 to 60 liters.
When this oxygen is heated to body temperature and saturated to full humidity through molecular humidification, despite its high fluxes, it is considered comfortable.
High Flow Oxygen (HFO) consists of high flow oxygen that can deliver up to 100% heated and humidified oxygen at a maximum flow of 60 LPM through the nasal tips.
An air / oxygen blender can provide a precise oxygen supply independent of the inspiratory flow demands of the patient. Based on different bench and patient models, a positive end-expiratory pressure can be generated.
In these models, for approximately every 10 liters of flow supplied, approximately 1 cm / H2O of positive pressure is obtained.
High-flow oxygen can help prevent escalation to more invasive respiratory interventions and can help facilitate ventilator release.
It is best used to treat mild to moderate hypoxemia, help with mucokinesis, and provide an accurate percentage of oxygen delivery in patients with an inconsistent breathing pattern.
High-flow oxygen delivery has been used clinically in a wide spectrum of patient care areas.
It has been administered to patient populations in critical care units, emergency departments, and end-of-life settings, and has recently migrated to the home care setting.
In conclusion, the administration of oxygen is a common clinical intervention in patients with respiratory distress. Optimizing results often depends on selecting the correct oxygen delivery device.
When selecting an oxygen delivery device, the respiratory therapist should include the following in their recommendation: the goal of oxygen delivery, the condition and etiology of the patient, and the performance of the selected device.
There are a large number of oxygen delivery devices for the respiratory therapist to choose the desired clinical end point. Selection depends on the clinical pathophysiology and the physiological response of the patient.
Clinical evaluation and monitoring are essential to ensure patient safety and to achieve the desired clinical results when administering oxygen.