Oxygen Availability in India :In selecting an oxygen delivery device, the respiratory therapist should include the following in their recommendation: the goal of oxygen delivery, the patient’s condition and etiology, and the performance of the device being selected.
Explained; How Quality Oxygen Delivery Devices Will Increase Oxygen Availability in India
New Delhi (ABC Live India): Oxygen Availability in India India nowadays during second Wave
of COVID-19 is facing shortage of Medical oxygen, and Prime Minister Narendra
Modi is directly reviewing the COVID-19 situation on regular basis.
The Government of India is claiming that there is no shortage
of medical oxygen in India and in this emergent situation; we can enhance the availability
of oxygen to needy COVID-19 hit patients by using high quality oxygen delivery
ABC Research team is referring a research article written by Kenneth
Miller in the public interest and if this information is used for utilizing
available medical oxygen judiciously then this can save thousands lives.
Oxygen administration is routinely utilized on the majority
of patients admitted the emergency room or ICU with respiratory distress.
Indications for oxygen administration include hypoxemia, increased working of
breathing, and hemodynamic insufficiency.
The overall goal of oxygen therapy administration is to
maintain adequate tissue oxygenation while minimizing cardiopulmonary work.
Signs of inadequate
oxygenation include tachypnea, accessory muscle work, dyspnea, cyanosis,
tachycardia and hypertension. Oxygen administration can also be utilized for
chronic administration for patients with advance cardiopulmonary disease and
can be administered during diagnostic assessment or assessment.
Currently, there is a wide array of oxygen delivery devices
available to the respiratory therapist to utilize for administration. The
choice of oxygen delivery devices depends on the patient’s oxygen requirement,
efficacy of the device, reliability, ease of therapeutic application and
Although design plays an important role in selection of these
devices, clinical assessment 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 costly.
Oxygen percentage delivery can be inconsistent or precise depending on the type
of administration device selected. Oxygen administration can be delivered via
low-flow or high-flow systems, with humidity or not, and with a reservoir or
not. Monitoring of oxygen delivery effectiveness includes arterial blood gas
analyses, oxygen saturation monitoring, and clinical assessment. Oxygen can be
considered toxic if percentages are delivered greater than 60%, and in the
chronic carbon dioxide retention patient population it may diminish ventilator
drive and produce life threatening hypercarbia. It can also cause absorption
atelectasis by washing out nitrogen gas when delivered in high concentrations.
Oxygen delivery devices have historically been
categorized into three basic types based on their design: low-flow, reservoir,
and high-flow. Regarding the inspiratory oxygen fraction (FiO2) range, oxygen systems can be divided into
those indicated for low oxygen (<35>60%). Some devices can deliver a wide range of oxygen percentages.3 When selecting an oxygen delivery device the
respiratory therapist must address two key questions. First, how much oxygen
can the device deliver? Second, is the FiO2 delivery
consistent, or can it vary with changing respiratory patterns?
A review of the different oxygen
delivery devices, clinical indications, and utilization will follow.
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 be diluted with ambient air and thus the inspired
oxygen delivery is less than anticipated. Low-flow oxygen delivery systems
consist of nasal cannula, nasal catheters, and transtracheal catheters.
The standard nasal cannula delivers an FiO2 of 24-44% at supply flows ranging from 1-8
liters per minute (LPM). The formula is FiO2 = 20% + (4 × oxygen liter flow). The FiO2 is influenced by breath rate, tidal volume
and pathophysiology.4 The slower the inspiratory flow, the higher the FiO2; the faster the inspiratory flow, the lower the
FiO2. Since the delivered oxygen percentage is very inconsistent
during respiratory distress, a nasal cannula is not recommended for acute
severe hypoxemia or patients that breathe on a hypoxic drive where too high of
an oxygen concretion may lead to respiratory depression. A nasal cannula
utilizes no external reservoir of oxygen and relies on the patient’s upper
airway as an oxygen reservoir. A humidification device is recommended for flows
greater than 4 LPM to insure humidification of the dry inspired gas.5 Even with humidity, added flows 6-8 LPM
can cause nasal dryness and bleeding. The best clinical indications for the
nasal cannula are for patients who have a relatively stable respiratory
pattern, who require low oxygen percentage, or who need supplemental oxygen
during an operative or diagnostic procedure, or for chronic home care.
A nasal catheter is a soft paste tube with several holes at
the tip. It is inserted into a nare, which needs to be changed every eight
hours. This device has been replaced by the nasal cannula but it can be used
for a patient that is undergoing an oral or nasal procedure.
deliver oxygen directly into the trachea. There are washout and storage effects
that promote gas exchange, as well as provide high-flow oxygen. High-flow
transtracheal catheters may reduce the work of breathing and augment 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, mean
oxygen savings amount to 50% at rest and 30% during exercise. Transtracheal
oxygen reduces dead space ventilation and inspired minute ventilation while
increasing alveolar ventilation slightly, which may result in a reduction of
the oxygen cost of breathing. As a result, patients using this device may
experience improved exercise tolerance and reduced dyspnea.6 This delivery device is best used for home
care and ambulatory patients who require long periods of mobility and do not
feel comfortable wearing a nasal cannula.
Reservoir systems incorporate a mechanism for gathering and storing oxygen during inspiration and exhalation. Patients draw from the oxygen reservoir anytime their minute ventilation flow exceeds the device delivery flow. Types of reservoir devices include cannula and masks.
Reservoir cannulas improve the efficiency of oxygen delivery. These devices are designed to conserve oxygen. Hence, patients may be well oxygenated at lower flows. Liter flows up to 8 LPM have been reported to adequately oxygenate patients with a high-flow requirement. It has been concluded that the reservoir cannula provides effective oxygen delivery to patients at supply flows substantially less than the standard nasal cannula. The reservoir can be located under the nasal cannula or hang as a pendant around the patient’s neck. The device is aesthetically acceptable to patients and its widespread use in patients requiring chronic oxygen therapy could bring about significant financial savings.7 Similar to transtracheal oxygen, this device is best employed on chronic oxygen users who wish a greater degree of mobility than traditional oxygen systems provide.
To increase the oxygen concentration delivered, often a mask
reservoir is utilized. The volume of the facemask is approximately 100-300 cm3 depending on size. It can deliver an FiO2 of 40-60% at 5-10 liters.8 The FiO2 is influenced by breath rate, tidal volume
and pathology. A flow rate of greater than 5 LPM must be set to ensure the
washout of exhaled gas 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 obtrusive,
uncomfortable, and confining. It muffles communication, obstructs coughing, and
impedes eating. It can also mask aspiration in the semi-conscious patient. A
simple mask should be administered for only a few hours because of the low
humidity delivered and the drying effects of the oxygen gas. This device is
best used for short-term emergencies, operative procedures, or for those
patients where a nasal cannula is not appropriate.
The non-rebreathing facemask is indicated when an FiO2 >40% is desired and for acute
desaturation. It may deliver an FiO2 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 major drawback is that the mask must
be tightly sealed on the face, which is uncomfortable and drying. There is also
a risk of CO2 retention if the mask reservoir bag is allowed to
collapse on inspiration. Humidification is difficult with this device, because
of the high-flow required and the possibility of the humidifier popping off.
This device is best utilized in acute cardiopulmonary emergencies where high FiO2 is necessary. Its duration should be less
than four hours, secondary to inadequate humidity delivery and to variable FiO2 for patients who require a precise high
High-flow oxygen delivery systems supply a given oxygen
concentration at a flow equaling or exceeding the patient’s inspiratory flow
demand. Often an air-entrainment or a blending system is used. As long as the
delivered flow exceeds the patient’s total flow, an exact delivered FiO2 can be achieved.
A Venturi mask mixes oxygen with room air, creating
high-flow enriched oxygen of a desired concentration. It provides an accurate
and constant FiO2 despite varied respiratory
rates and tidal volumes. FiO2 delivery settings are
typically set at 24, 28, 31, 35 and 40% oxygen. The Venturi mask is often
employed when the clinician has a concern about CO2 retention
or when respiratory drive is inconsistent. The addition of humidification is
not necessary with this device, secondary to the large amount of ambient
entrainment that occurs to ensure the exact FiO2 is
delivered.10 The Venturi mask is often utilized in the
COPD patient population where the risk of knocking out the patient’s hypoxic
drive is of concern.
An aerosol-generating device will deliver anywhere from 21 to
100% FiO2 depending on how it is set up. The flow is usually set
at 10 LPM and the desired FiO2 is selected by adjusting an entrainment
collar located on top of the aerosol container. The humidity device is
connected to the flow meter, and wide bore tubing connects this to the
patient’s mask. Wide bore tubing and the reservoir bag are placed in line to
act as an oxygen reservoir to ensure an exact high FiO2 is delivered. This device adds water content
to the patient and can assist in liquefying retained secretions. This
oxygen delivery option is ideal for patients with tracheotomies because it
allows for inspired air to be oxygenated, humidified, and even heated if
necessary. They can be hooked up to a mask, tracheotomy mask, and even a
T-piece. If the patient’s flow exceeds the total flow delivered (ambient
entrainment and 10 LPM), the patient may retain CO2 and the FiO2 may be lower than desired.11 During inhalation, an aerosol mist should be seen
coming from the mask or reservoir. To ensure accurate oxygen administration via
this system, an oxygen analyzer should be used. This device can be used to
ensure a precise oxygen delivery and also maintain humidification of artificial
relatively new oxygen delivery device is a high-flow nasal cannula (HFNC) system.
Nasal oxygen has been administered at flows ranging from 10-60 liters. When
this oxygen is warmed to body temperature and saturated to full humidity via
molecular humidification, despite its high flows, it is deemed comfortable.
High-flow oxygen (HFO) consists of a heated, humidified, high-flow nasal
cannula that can deliver up to 100% heated and humidified oxygen at a maximum
flow of 60 LPM via nasal prongs or cannula.
An air/oxygen blender can provide precise oxygen delivery
independent of the patient’s inspiratory flow demands. Based on different bench
and patient models, positive end-expiratory pressure may be generated.In these models, for approximately every 10
liters of flow delivered, about 1 cm/H2O of positive
pressure is obtained. High-flow oxygen may help
prevent escalation to more invasive respiratory interventions and can help
facilitate ventilator liberation. It is best used to treat mild to moderate
hypoxemia, to help aid with mucokinesis, and to provide an exact oxygen
delivery percentage in patients with an inconsistent respiratory pattern. HFO
delivery has been clinically utilized in a wide spectrum of patient care
arenas. It has been administered to patient populations in critical care units,
emergency departments, and end-of-life scenarios, and recently has migrated
into the home care environment
In conclusion, oxygen administration is a common clinical
intervention for patients with respiratory distress. Optimizing outcomes often
depends on selecting the correct oxygen administration device. In selecting an
oxygen delivery device, the respiratory therapist should include the following
in their recommendation: the goal of oxygen delivery, the patient’s condition
and etiology, and the performance of the device being selected. There are a
plethora of oxygen delivery devices for the respiratory therapist to choose
from to meet the desired clinical endpoint — selection depends on the clinical
pathophysiology and the patient’s physiological response. Clinical assessment
and monitoring are essential to ensure patient safety and to achieve desired
clinical outcomes when administering oxygen.