Topic Discussion Oxygen Therapy.doc

7/25/2019 Topic Discussion Oxygen Therapy.doc

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TOPIC DISCUSSION

OXYGEN THERAPY

Andria Amanda Pulungan

1106127784

Gerald Alain Aditya 1106064676

Karin Nadia Utami 1106127765

Raisha Basir

1106127752

Supervisor:

Dr. Adria Rusli, SpP


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FACULTY OF MEDICINE UNIVERSITY OF INDONESIA

PULMONOLOGY CLINICAL PRACTICE MODULE

JAKARTA

APRIL 2016

Table of content

Indication of oxygen therapy 3

Administration of Oxygen Therapy 7

Oxygen delivery equipment

9

Side Effects of Oxygen Therapy 13


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Indication of oxygen therapy

Oxygen is a treatment for hypoxemia, not breathlessness. Oxygen has not been shown to have

any effect on the sensation of breathlessness in non-hypoxemic patients. Oxygen therapy is a

management therapy to give additional oxygen, especially for patient with heart and lung

problems. The primary indication of oxygen therapy is for hypoxemia patient, which is a state

of decline partial pressure of oxygen (PaO2) in the blood < 60mmHg or oxygen saturation

(SaO2) < 90%

that is proved by supporting examination in the form of blood gas analysis.

Another indications are for patient with severe trauma, acute myocardial infarction, shock,

shortness of breath, carbon monoxide poisoning, post anesthesia, and other acute situation

because of hypoxemia.

The oxygen therapy target is to maintain Pa02 > 60mmHg or SaO2 > 90% to prevent hypoxic

cells and tissue and also to decrease the work of breathing and heart muscles.1,2

Indication of long term oxygen therapy , include:

1. Hypoxaemia when you wake up and rest:

a. PaO2< 55 mmHg or

b . PaO2 55-59 mmHg with evidence of end-organ dysfunction are due to chronic

hypoxic shown by P pulmonal, right heart failure, and eritrositosis.

2. Chronic hypoxemia (3-4 weeks after diagnosis), which settled lower PaO2 ,SaO2 < 89 % for the condition 1a , SaO2 89 % for conditions 1b .

1

Administration of oxygen as a drug could be given as a supplement and therapy

1. Oxygen supplementOxygen supplement is given in an acute hypoxemic condition and for many others

patient who are at risk of hypoxemia, including patient with major trauma and shock,

which need oxygen < 30 days, such as in pneumonia and acute asthma.1,2

2. Oxygen therapy Short-term oxygen therapy


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It is given for patient that need oxygen therapy in 30-90 days, such as a patients

with congestive heart failure.

Long-term oxygen therapy

It is given for patient that need oxygen therapy > 90 days, such as patients with

COPD.1,2

Hypoxemia

Hypoxemia is a condition when the oxygen partial ressure (PaO

2) in the blood drops, when

PaO2< 60 mmHg or SaO

2< 90 % in adults, children, and infants aged more than 28 days. For

neonates, it is called hypoxemia if PaO2< 50 mmHg or SaO2 < 88 %.

1

There are several mechanisms of hypoxemia :

Impaired ventilation-perfusion / (V/Q mismatch)

This disorder or disturbance is the most common cause of hypoxemia and it has a

good response by administering small doses of oxygen. This disorders can be caused

by obstructive lung disease such as (COPD, asthma, emphysema, chronic bronchitis),

sputum retention, cardiovascular disease (myocardial infarction and congestive heart

failure).1,2

Hypoventilation alveolar

Alveolar ventilation is an air exchange process in alveolus. In hypoventilation

alveolar, there is an increasing pressure of arterial CO2 ( PaCO2 > 45 mmHg). This

situation can occur when a drug overdose, sleep apnea, and acute exacerbations of

COPD. Oxygen therapy is only able to cope with hypoxemia, but not fix the

ventilation.1,2

Shunt

Shunting occurs when oxygenated blood mixing with the deoxygenated because the

alveoli are not ventilated. The magnitude of the shunt affect the magnitude of

decrease in PaO2. This condition can be found in the case of pneumonia, acute

respiratory distress syndrome (ARDS), atelectasis, pulmonary edema, and pulmonary

embolism. In these circumstances, the oxygen required high doses and therapeutic

interventions to address the alveoli collapse example with continuous positive airway

pressure (CPAP), overcoming ateletaksis or improve the work of the heart in

cardiogenic pulmonary edema with inotropic drugs or diuretics.1,2

Impaired diffusion

The cause is a thickening in the area between the capillaries and alveoli, which

caused by the interstitial edema, sarcoidosis, and asbestosis.1,2

Decrease the pressure of inspired oxygen

Decrease the pressure of inspired oxygen can be occurs in people with impaired

function of hemoglobin such as anemia and bleeding; it can also occurs in person at

high altitude.1,2

Hypoxemia detection

There are some ways to detect the state of hypoxemia, which are:


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Clinical symptoms

Cyanosis : SaO2 < 85 % fatigue, disorientation, lethargy, coma, tachypnea, dyspnea,

tachycardia / bradycardia, arrhythmia, hypertension / hypotension, polycythemia, and

clubbing finger.

Examination of blood gas analysis

Blood gas analysis examination is done to evaluate PaO2 and oxygen saturation

(SaO2). Oxygen saturation is the amount of oxygen that can bind to hemoglobin. The

degree of saturation depends on the shape and position of the oxyhemoglobindissociation curve is influenced by pH, PaCO2, temperature, and 2,3

diphosphoglycerate (2,3 - DPG).

Pulse oxymetry

It is a noninvasive method for monitoring a persons oxygen saturation (SaO2)

Transcutaneous partial pressure of oxygen (PtcO2)

It is commonly used in the PICU for child, it is also used for adults but more common

used to monitor the results of vascular surgery compared to see oxygen pressure.1,2

Evaluation of hypoxemia

Comparing the drop in PaO2with the clinical condition of the patient.

If the laboratory results indicate serious respiratory disorders, but

patients are seen normal, the laboratory examination can be repeated.

Finding the cause of hypoxemia such as performing a physical

examination to find the cause of the decline in PaO2, if the result of

PaCO2, > 45mmHgcan be caused by alveolar hypoventilation.

Radiographic examinations and laboratory examinations.

Counting "alveolar -arterial oxygen gradient" (A-a DO2) ! PAO

2 -

PaO2PAO

2is obtained from the alveolar gas equation and the PaO

2is obtained from the

blood gas analysis, with the result shows:

A-a DO2< 20mmHg normal

A-a DO220-40 mmHgV / Q mismatch

A-a DO240-60 mmHg shunts

A-a DO2> 60 mmHgdisturbance of diffusion

1


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Administration of Oxygen Therapy

The administration of oxygen therapy should be done as simple as possible with the lowest

possible FiO2, but still keeping the level of PaO2 >60mmHg, and SaO2>90%. The method of

administration is chosen according to the level of FiO2 that is needed, the patients comfort,

the level of humidity required, and the need of nebulization therapy.1

Based on the difference of oxygen concentration level that is supplied by the device and thatis entered to the lungs, the administration of oxygen therapy is divided into:

Low-flow (variable performance) devices

Low-flow devices give lower oxygen contration than what the patient inhaled. It

varies according to the amount of gas that flows out of the device and the patients

breathing pattern. Some of the examples of low-flow devices are nasal cannule and

oxygen masks1.

High-flow (fixed performance) devices

The oxygen concentration that is administered is stabile and is according to what the

patient inhaled. Some examples of high-flow devices are ventury mask and


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continuous positive airway pressure (CPAP)1.

Patients with administration of oxygen therapy also needs to evaluated and observed. This can

be done with:

Physical examination, observation of clinical symptoms

On physical examination, we can find that there is improvement of the symptoms

such as arrhytmia, cyanosis, and tachypnoe. Other symptoms such as fatigue and

disorientation could also be relieved

1

Additional examination

Blood gas analysis can be done 15-20 minutes after oxygen therapy is given. There

can be found changes such as an increase in partial oxygen pressure1.

To determine the level of oxygen that is needed, these steps are used:

1. Determine the level of oxygen concentration in alveolus (PAO2)

PAO2

={(PB PH2O) x FiO

2} (1,25 x PaCO

2)

PB: barometer pressure (760 mmHg)

PH2O: partial H2O pressure (47 mmHg)

PaCO2: partial CO2 pressure (based on results of blood gas analysis)

FiO2 can be determined by using the table below:

Devices O2(L/minute) FiO2

Nasal Cannula 1-2 0,21-0,24

2 0,23-0,28

3 0,27-0,34

4 0,31-0,38

5-6 0,32-0,44

Ventury Mask 4-6 0,24-0,28

8-10 0,35-0,40

8-12 0,50

Simple Face Mask 5-6 0,30-0,45

7-8 0,40-0,60

Rebreathing Mask 7 0,35-0,75

10 0,65-1,00

Non rebreathing Mask 4-10 0,40-1,00

2. Determining the level of PAO2 that is needed (in order to achieve

PaO2>60 mmHg)1


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3. Determining the level of FiO2 that is needed to achieve PAO2

according to calculation number 2.1

PAO2={(PB PH

2O) x FiO

2} (1,25 x PaCO

2)

4. Re-matched the result to the previous table, see how many liters of

oxygen that should be given according to the previous FiO2 result.1

Oxygen delivery equipment

Simple face mask

Simple face mask delivers oxygen concentrations between 40% and 60%. The oxygen

supplied to the patient will be of variable concentration depending on the flow of oxygen and

the patients breathing pattern. The concentration can be changed by increasing and

decreasing the oxygen flows between 5 and 10 l/min. Flows of 5 l/min can cause increased

resistance to breathing and there is a possibility of a build up carbon dioxide within the mask

and rebreathing may occur.2

Simple facemask is suitable for patients with hypoxaemic respiratory failure but is not

suitable for patients with hypercapnic respiratory failure. The mask is not recommended for

patients who require low dise oxygen therapy because the simple face mask deliver a highconcentration of oxygen.


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Figure 1 Simple face mask2

Reservoir mask

These type of mask is similar to simple mask however this mask has a reservoir bag. The

reservoir can hold until 600 mL The mask is divided into non-rebreathing and rebreathing

mask. Non rebreathing mask has a valve that when you exhale, the air can go through the

hole in the valve. Therefore when you inhale, only oxygen that the patient inhale.

Non-rebreathing mask delivers oxygen at concentrations between 60% and 90% when at a

flow rate of 10-15 l/min. The concentration is not accurate and will depend on the flow of

oxygen and the patients breathing pattern. These type of mask are most suitable for trauma

and emergency use where carbon dioxide retention is unlikely.

Figure 2 Non-rebreathing mask2


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Venturi mask

This type of mask will give an accurate concentration of oxygen to the patient regardless of

oxygen flow rate. The oxygen concentration remains constant because of the venturiprinciple. The gas flow into the mask is diluted with ait which goes in through the cage on the

venture adaptor. The amount of air sucked into the cage is related to the flow of oxygen into

the venture system. The higher the flow rate, the more the air will be sucked in. The

proportion remain the same, therefore the venture mask will delivers the same concentration

of oxygen regardless the increase of the flow rate.

The concentrations that are available in the venture masks are 24%, 28%, 35%, 40% and

60%. These type of mask are suitable for patients that need a known concentration of oxygen.

Venturi mask with a concentration of 24% and 28% are suitable for patients at risk of carbon

dioxide retention. The effect on the patient will depend on the condition being treated,

breathing pattern and oxygen saturation of the patient. Patient who have an oxygen saturationin a normal range will have a very small increase in oxygen saturation. If the patient has very

low oxygen saturation, the oxygen saturation will have a significant rise.

Nasal cannulae

Nasal cannulae can give low and medium dose oxygen concentrations. The oxygen levels and

carcon dioxide may be vary in different patients because there is a variation of breathing

pattern between patient even tough the flow the rate is the same. The pipe of nasal cannulaecan be connected to the humidifier with the flow rate of oxygen between 2-6 litre/min. If the

flow rate is more than 2 litre/min, the patient may experience discomfort and nasal dryness.

Figure 3 Nasal Cannulae2


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The are several devices that were used as oxygen storage and provision:

Cylinder

Cylinder contains compressed gas detained under a very high pressure. Cylinder can be used

for bedside administration where piped oxygen is not available or can be the supply of piped

system.

Liquid oxygen

Liquid oxygen contained in a pressure tank and acquired from atmospheric oxygen. Large

tanks are often used in the hospitals, where as the small one can be use domestically.

Oxygen concentrators

Oxygen concentrators are largely used for long-term oxygen therapy, therefore this oxygen is

not used for acute setting

Side Effects of Oxygen Therapy

In case of hypoxemia, or few other conditions, oxygen therapy can be a life saving procedure.

However, in some cases, the excessive administration of oxygen can do more harm to thepatient, rather than saving them.

The side effects can range from simple to dangerous one; first of all, oxygen can cause injury

to the nose/mouth because oxygen causes dryness. In addition, nitrogen is more common in

open air compared to oxygen, those nitrogen acts to maintain alveoli so that it will not

collapse, in some circumstances where patient is administered high pressure of pure oxygen,

nitrogen can get pushed out and collapsing the alveoli.1


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Furthermore, patients who have prolonged exposure to inspiratory oxygen fraction >50%

could experience oxygen toxicity. Oxygen toxicity happens when oxygen molecules are

converted into radicals that are toxic to lung cells. Ultimately, oxygen toxicity can cause

pathophysiological changes such as decreased lung compliance, reduced inspiratory airflow,

and decreased oxygen diffuse.

Another side effect that can happen due to prolonged oxygen therapy is carbon dioxide

retention. Carbon dioxide retention can lead to reduced in respiratory drive, and hypercapnia,

that ultimately resulting in respiratory acidosis.

References

1. Rasmin M. Terapi Oksigen. 1stedition. Jakarta: Perhimpunan

Dokter Paru Indonesia; 2006. p. 7-9.

2. British Thoracic Society. Guideline for emergency oxygen usein adult patients. Thorax2008; 63(VI): 168.


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