oxygen therapy

Introduction Introduction

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OXYGEN THERAPYOXYGEN THERAPY

J.Nandhakumar MSc (N) I YEAR

College of nursing MTPG & RIHS

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Oxygen was discovered by JB Priestley in 1773

Composition of Room AirComposition of Room AirNitrogen 78.08% ~78%Oxygen 20.946%~21%Trace gases ~1%

Definition:Definition:

*Oxygen therapy is the administration of oxygen at concentrations greater than room air ( 21%)

*With goal of treating or preventing the symptoms and manifestations of hypoxia(a state of oxygen deficiency reaching the tissues)

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Topics of DiscussionTopics of Discussion

*Types of Hypoxia*Signs and symptoms of Hypoxia*Indications *O2 delivery Systems*Hazards o2 therapy

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HYPOXIAHYPOXIAInadequate oxygen being delivered to the cells

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Types of HypoxiaTypes of Hypoxia

1-Hypoxic Hypoxia2-Circulatory Hypoxia3-Hemic Hypoxia4-Demand Hypoxia5-Histotoxic Hypoxia

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Hypoxic HypoxiaHypoxic Hypoxia*Low PaO2(arterial oxygen tension)

which is secondary to FiO2 < 21% or decreased barometric pressure( high altitude )

*Impaired ventilation secondary to neuromuscular weakness or narcotic overdose

*Impaired oxygenation secondary to Pulmonary Fibrosis, ARDS

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Circulatory HypoxiaCirculatory Hypoxia*Inadequate pumping of the blood

from the lungs to tissues , maybe secondary to disorders causing decreased cardiac output such as MI, low fluid volume, hypotension, poor supply of arteries. If the patient has myocardial ischemia supplemental O2 is definitely indicated.

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Hemic HypoxiaHemic Hypoxia

Decreased oxygen carrying capacity as in anemia or carbon monoxide poisoning

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Demand HypoxiaDemand Hypoxia

Increased tissue consumption of oxygen in hypermetabolic states : like fever, malignant hyperthermia

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Histotoxic Hypoxia Histotoxic Hypoxia

Utilization of oxygen is abnormal such as in cyanide poisoning

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Signs and Symptoms of Signs and Symptoms of HypoxiaHypoxia

Tachypnea, dyspneaTachycardia, dysrythmias, pulse

change, hypertensionAnemia, Restlessness, disorientation,

lethargy,Cyanosis, clubbing

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IndicationsIndications1)PaO2 <60mmHg or SaO2 <90% in subjects

breathing room air.PaO2=partial pressure of oxygen as measured in

the arterial blood, SaO2=hemoglobin’s saturation 2)Acute situation where hypoxemia is suspected3)Severe trauma4)Acute myocardial infarction5)Short term, post operative

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DefinitionsDefinitionsFiO2= Fraction of inspired oxygen, or

the percent of oxygen in the inspired gas

Oxygen toxicity is cellular injury of the lung parenchyma and airway epithelium due to release of cytoxic free oxygen radicals.

There is no exact threshold at which O2 toxicity occurs, however signs of gas exchange abnormalities occur within 24-48 hours if on 100% oxygen. Atelectasis leading to drop in PO2, decreased lung compliance, infiltrates on x-ray.

Breathing FiO2 up to 50 % for 2-7 days usually does NOT result in toxicity. 04/11/23 17

DEVICESDEVICES

The oxygen delivery devices can be categorized as

Low flow systemsReservoir systemsHigh flow systemsEnclosure systems

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Oxygen TherapyOxygen TherapyDesign & PerformanceDesign & Performance

Low flow Devices Flow does not meet inspiratory

demand O2 is diluted with air on inspiration Devices deliver Fio2 ranging from

22-60%E.g Nasal cannula Transtracheal catheter

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Nasal CannulaNasal Cannula

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NASAL CANNULANASAL CANNULA low oxygen devicelow oxygen device

This device delivers an unpredictable amount of oxygen ranging from 25-45 % at 1 - 6 L/min depending on how much the patient inhales through the mouth

Higher flow rates are uncomfortable for the patient

A high flow rate can quickly dry out the nasal mucosa and become rapidly uncomfortable

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NASAL CANNULA Cont…NASAL CANNULA Cont… low oxygen devicelow oxygen device

Delivers 25-45% FIO2 at 1-6 L/min flow 1. Flow 0 liters per minute: 21%

(Room Air) 2. Flow 1 liters per minute: 25% 3. Flow 2 liters per minute: 29% 4. Flow 3 liters per minute: 33% 5. Flow 4 liters per minute: 37% 6. Flow 5 liters per minute: 41% 7. Flow 6 liters per minute: 45%

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Reservoir SystemReservoir System Simple oxygen face mask Partial rebreathing mask Nonrebreathing mask

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SIMPLE FACEMASKSIMPLE FACEMASK low oxygen devicelow oxygen device

The simple facemask at an oxygen flow of 6 L/min delivers approximately 35-40 % oxygen

Increasing the flow to 10 L/min may increase oxygen concentration to about 50 %

If the flow rate is less than 6 L/min (as cylinder nears empty), the patient may re-breathe much of his own exhalation and thus, the concentration of oxygen delivered will be low, possibly severely hypoxic

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Partial Rebreathing Mask with reservoirPartial Rebreathing Mask with reservoir

Moderate oxygen deviceModerate oxygen device

Delivers 35-60% Oxygen at 6-10 L/min flow rate Ω First third of exhaled gases mix with

reservoir Ω Exhaled gases from upper airway are

oxygen rich

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Reservoir

Non-Rebreathing Mask with Non-Rebreathing Mask with reservoirreservoir

High oxygen deviceHigh oxygen device

Delivers 95% Oxygen at 10-12 L/min

Two valves added to Rebreathing mask prevents: Entrainment of room air during

inspiration Retention of exhaled gases during

expiration

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Valves

High Flow systemHigh Flow system

It provide oxygen at flow rates high enough to satisfy patient’s inspiratory demands.

Such high flows( i.e. 35-40 lit approx) are possible by

1.Entrainment of room air2.High flow rates and reservoirsE.g Venturi masks High flow aerosol nebuliser04/11/23 29

Oxygen TherapyOxygen TherapyHigh Flow Devices - High Flow Devices - EntrainmentEntrainmentAE Devices

AEM (Venti-Mask)

AE Nebulizer (Large Volume Nebulizer) cool/heated Aerosol

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Oxygen TherapyOxygen TherapyHigh Flow DevicesHigh Flow Devices

Air Entrainment systemWhat is Entrainment?

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VENTURI EFFECTVENTURI EFFECT

Oxygen is forced through a jet orifice entering the mask. As there is pressure drop across jet orifice, room air entrainment occurs through side ports

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Venturi MasksVenturi MasksVenti-MasksVenti-Masks

Can provide 24%-50% oxygen by mixing room air with a precise amount of oxygen thereby delivering a precise FiO2. The size of the port and the oxygen liter flow determine the FiO2. The mask should be fitted to the patient as best as possible to prevent entrainment of room air around the mask which would alter the FiO2.

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Air Entrainment Mask

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Reference ChartReference Chart

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Method FiO2

(Approximate)

Flowrate

(L/min)

Non rebreather Mask 60-80% 10-15

Venti Mask 24%

26%

28%

31%

35%

40%

50%

3

3

6

6

9

12

15

Simple Face Mask 35-55% 5-10lpm

Nasal Cannula 24%

28%

32%

36%

40%

44%

1

2

3

4

5

6

Enclosure systemsEnclosure systems

Tents Hoods

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Oxygen HoodOxygen Hood High oxygen deviceHigh oxygen device

Clear plastic shell encompasses the baby's head Well tolerated by infants Size of hood limits use to younger than age 1

year Allows easy access to chest, trunk, and

extremities Allows control of Oxygen Delivery:

o Oxygen concentration o Inspired oxygen temperature and humidity

Delivers 80-90% oxygen at 10-15 liter per minute

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CPAPCPAP

Administering oxygen by

CPAP(continuous positive airway pressure):

1-Nasal CPAP.2-Endotracheal CPAP.

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Nasal CPAPNasal CPAP::

Nasal CPAP: It consists of a single nasopharyngeal tube that deliveries 2-8 cm of positive pressure with or without o2.

Nursing care : - Frequent suction .- Tube care.- Change the nasal tube.

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Endotracheal CPAPEndotracheal CPAP

Endotracheal CPAP: Positive pressure delivering via an ETT.

Nursing care : - Use sterile suctioning

techniques- Mouth care - Change the ETT every seven

days .

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Oxygen HazardsOxygen HazardsFire ( airway fires) Tissue toxicity, pulmonary and

retinaDecreased hypoxemic drive and

increased in COPD.Seizures (hyperbaric)Mucosal damage due to lack of

humidity

Complications of oxygen Complications of oxygen adm…adm…1- Air way obstruction(thickened

secretions, mechanical problems with artificial airway or ventilator circutory.

2- Tracheal damage 3- pulmonary infection4- Barotrauma (pneumothorax or

tension pneumothorax)

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Cont….Cont….

5- Decrease cardiac output.6- Atelectasis.7- Alteration in

GI(dilation,bleeding).8- Alteration in renal function.9- Alteration in cognitive

perceptual status

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Take home messageTake home messageAcute empiric oxygen treatment is ok but

hypoxemia should be verified with pulse oximetry and /or ABG’s when situation more stable.

Oxygen is a drug and should be administered keeping following things in mind: mode of administration, flow rate, FiO2 (venturi), treatment goal, monitoring, when to stop.

Merci …..Merci …..

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oxygen therapy

Technology