03 Penerapan Terapi Oksigen Pada Kegawat Daruratan Dengan Aplikasinya

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Oxygen Therapy

UKK PGD - IDAI

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Goals and Indications

• Goals : is to provide tissue oxygenation at the lowest inspired FiO2

• Indications :1. Documented Hypoxemia

• Infants & Children : PaO2 < 60 mmHg or SaO2 < 90% (breathing room air)

• Neonates : PaO2 < 50 mmHg or SaO2 < 88%

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• Indications2. In Acute care situation in which hypoxemia is

suspected :• Shock

• Severe trauma

• Short term therapy (during certain medical procedures)

Goals and Indications

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Contraindications

• No specific contraindications

• Nasal cannulas : Nasal Obstruction

• Nasopharyngeal catheters : Basal skull fracture, Maxillofacial trauma & Nasal obstruction

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Hazards, Precautions & Complications

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Relation between PO2 and exposure time for O2 toxicity

Time (hours)

Insp

ired

PO

2 (a

tm)

8

7

76

6

5

5

4

4

3

3

2

2

1

1 Several days

CNS limits

Pulmonary limits

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Increased FiO2

O2 Toxicity

Low PaO2

Increased Shunting

The vicious circle that can occur in managing hypoxemia with High FiO2

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Hazards, Precautions & Complications

• Physiologic:• Preterm infants (ROP)

• Paraquat, bleomycin : pulmonary fibrosis

• High FiO2 : Absorption atelectasis, BPD, free radicals

• Equipment related• Hypoxemia, Hyperoxemia

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Overview of the transport of gases

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• O2 transported from lungs to tissues.

• O2 moves down a partial pressure gradient at each interface:• From alveolar gases into blood.

• From arterial blood into tissues.

• Into cells and into mitochondria.

• CO2 transported from tissues to lungs.

• CO2 moves down a partial pressure gradient at the same interfaces.

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PO2 = 100

PO2 = 100

PO2 = 40

PO2 = 40

PCO2 = 40

PCO2 = 40

PCO2 = 46

PCO2 = 40

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PAO2

Oxygenation

• The key factors which affect adequate oxygenation:

• FiO2 (affect Alveolar O2 tension)

• Alveolar gas exchange

• The mixed venous oxygen content

• The distribution of ventilation to perfusion

FiO2

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Alveolar Oxygen Tension

FiO2 PAO2

• PAO2 = (PB - PH2O)FiO2 - PaCO2/RQ• PAO2 = Alveolar O2 tension

• PB = Barometric pressure (760 mmHg at sea level)

• FiO2 = fraction of inspired oxygen

• PaCO2 = arterial CO2 pressure

• RQ = respiratory quotient = 0.8• PH2O = Water vapor tension (47 mmHg)

PAO2

FiO2

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Alveolar Oxygen Tension

• PAO2 = (PB - PH2O)FiO2 - PaCO2/RQ

• PAO2 = (PB - PH2O)FiO2 - PaCO2/0.8

10 years old boy in Surabaya breathing room air

• PAO2 = (PB - PH2O)FiO2 - PaCO2/0.8

• PAO2 = (760- 47)0.21 - 40/1.25 = 100 mmHg

PAO2

FiO2

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Oxygen in Blood

• O2 is held in 2 compartments in blood– Physically dissolved in plasma– Chemically bound on hemoglobin

• Solubility of O2 in plasma = 0.003ml/dl blood/mmHg

• The effective carrying capacity of Hb = 1.34 ml O2/g Hb

20 40 60 80 100 120 140 180 2000

PO2

5

10

15

20

25

Hb = 15 g/dL

Hb = 8 g/dL

Dissolved O2

O2

Con

tent

(m

L/1

00m

L)

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0.40.2 0.6 0.8 1.0

300

200

100

700

600

500

400

FiO2

Alv

eola

r P

O2

VA/Q = 1

VA/Q << 1

VA/Q > 1

. .

. .. .

West JB Respir Physiol 1969;7:8818

0.2 0.4 0.6 0.8 1.0

100

200

300

400

FiO2

Art

eria

l PO

20

10%

25%

50%

Arterial PO2 is plotted as a function of FiO2 for a variety of RL shunts(Benator SR, etal: Br J Anaesthesiol 1973;45:722)

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The Goal of Oxygen therapy

• To achieve adequate tissue oxygenation with the lowest fractional concentration of inspired oxygen (FiO2)

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100

80

60

40

20

20

15

10

5

0

120 140100806040200

PaO2 mmHg

CaO

2 m

l/d

l

Hb

15

gm

/dl

SaO

2 %

A

B

21

0 1 2 3 4 5 6 7 8

Duration of exposure, days

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.21

Fi02

Risk of clinical oxygen toxicity

Clinically safe

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Oxygen Administration

• Equipment : Smaller versions of the adult devices

• Low flow (Variable performance oxygen delivery systems)

• High flow (Fixed performance oxygen delivery systems)

• Reservoir • Enclosure

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Oxygen therapy devices

Low flow Reservoir High flow Enclosure

Nasal cannula

Nasal catheter

Simple mask

Partial rebreathing mask

Non rebreathing mask

Air entraintment mask

(Venturi mask)

Oxyhood

Incubator

O2 Tent

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A

BC

Flo

w

Insp.

Exp.

A = Low flow deviceB = High flow deviceC = Reservoir device

= Patient’s flow

= Device’s flow

Nasal cannula• Advantages

• Easy to use• Disposable• Useful for

moderate O2 need

• Disadvantages• Irritating nose and

throat (> 6 L/min)• Low FiO2• Variability in

actual FiO226

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Nasal cannula

• FiO2 determined by– Capacity of available O2 reservoir– O2 flow– Patient’s breathing pattern

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Nasal cannula

• Anatomic reservoir capacity– 2/3 ml/kgBW

• O2 flow– xL/min = x1000ml/60 sec = 16.7 ml/sec

• Breathing pattern– Cycle time– I : E ratio– The filling time anatomic reservoir

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2L/min O2 nasal cannula provided to a 5 kg infant

breathing 40 times/min (assuming I:E ratio of 1:2)

Tidal volume : 6 ml/Kg

Anatomic reservoir : 2/3 ml/Kg

O2 flow : 1L/min = 16.7ml/sec

Inspir. O2 Volume : Inspiratory time x flow

Room air (flow)

volume :

Tidal volume - (inspir O2 volume +

anatomic reservoir volume)

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2L/min O2 nasal cannula provided to a 5 kg infant

breathing 40 times/min (assuming I:E ratio of 1:2)

Tidal volume : 30 ml

Anatomic reservoir : 3.3 ml

Inspir. O2 Volume : 16.7 ml

Room air (flow) volume : 10 ml = 10 ml x 0.21 = 2.1 ml O2

Total O2 volume : 3.3 + 16.7 + 2.1 = 22.1 ml

FiO2 provided : Total O2 volume/Tidal volume = 22.1

ml/ 30 ml = 0.7430

2L/min O2 nasal cannula provided to a 5 kg infant, goes

sleep, breathing 30 times/min (assuming I:E ratio of 1:2)

Tidal volume : 6 ml/Kg

Anatomic reservoir : 2/3 ml/Kg

O2 flow : 1L/min = 16.7ml/sec

Inspir. O2 Volume : Inspiratory time x flow

Room air (flow)

volume :

Tidal volume - (inspir O2 volume +

anatomic reservoir volume)

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2L/min O2 nasal cannula provided to a 5 kg infant, goes

sleep, breathing 30 times/min (assuming I:E ratio of 1:2)

Tidal volume : 30 ml

Anatomic reservoir : 3.3 ml

Inspir. O2 Volume : 22.38 ml

Room air (flow) volume : 4.32 ml = 10 ml x 0.21 = 0.91 ml O2

Total O2 volume : 3.3 + 22.38 + 0.91 = 26.58 ml

FiO2 provided : Total O2 volume/Tidal volume = 26.58

ml/ 30 ml = 0.9032

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QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Recommended Flow meterFor newborn

Masks

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Partial rebreathing mask Nonrebreathing mask

High Flow Systems

• Air entraintment System

• Venturi Systems

• Enclosure Systems

• Fixed FiO2 (WYSWYG)

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Air entrainmentEntrainment port

Jet

Jet Jet

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Entrainment port

Jet

Venturi (by Giovanni Venturi)

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Equation for Computing O2 percentage, Ratio, and Flow

% O2 = (Air flow x 21) + (O2 flow x 100)Total flow

Liters airLiters O2

= (100 - %O2)(%O2 - 21)

1. To compute O2% of a mixture of Air and O2

2. To compute air-to-O2 ratio needed to obtain O2%

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3. To compute the total output flow from an air entrainment device (given the oxygen input)

• Compute the air-to-O2 ratio• Add the air-to-O2 ratio parts• Multiple the sum of the ratio parts by the O2 input flow

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4. To compute the flow of oxygen and air needed to obtain a given O2% at a given total flow

• Compute the oxygen flow:

• Compute the air flow:

O2 flow = Total flow x (O2% - 21)79

Air flow = Total flow - O2 flow

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FiO2

(%%)

O2 Flow

(L/min)

Total Flow

(L/min)

Red 24 3 105

Yellow 28 6 68

Blue 31 8 63

Orange 35 10 56

Green 40 12 33

Venturi Flow (Salter Lab Ideal)

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Color FiO2

(%)

O2 Flow

(L/min)

Total Flow

(L/min)

Blue 24 3 78

White 28 6 66

Orange 31 8 72

Yellow 35 12 72

Red 40 15 60

Pink 50 15 40

Venturi Flow (Hudson RCI)

Ventury Systems• Total flow 3 - 4 times minute ventilation• A 50 Kg asthmatic patients breathing 40

times per minute ( I:E = 1:3)• Minute volume = 50 x 6 x 40 = 9 Liters• Needs total flow = 9 x 4 = 36 L/minute• Please be informed about the total flow.

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Oxygen Hood

• Advantages– Permit access to the chest, trunk

and extremities for continue care

– Well tolerated by infants

– Can deliver up to 100% oxygen

(flow 10 - 15 L/min)

• Disadvantages

– Very noisy for the patients

– Generally not large enough to be used over the age of 1 year

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Low-flow High-flow Enclosure systems

FiO2 Variable Fixed Variable (depend on devices)

Newborn Nasal Cannula,Simple oxygen mask

An air entrainment mask (venturi systems)

Oxygen hoods,Closed incubators

Infant &

Children

Nasal cannula,Nasopharyngeal

catheters,Simple oxygen mask,

Reservoir masks

An air entrainment mask (venturi systems)

Oxygen hoods,Oxygen tents

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Monitoring

• Vital signs• O2 monitoring (FiO2)• SaO2• Blood gas analysis• P(A-a)O2• PaO2/FiO2

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Thanks to Priestley (1774) for discovering oxygen for us

03 Penerapan Terapi Oksigen Pada Kegawat Daruratan Dengan Aplikasinya

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