Arterial blood gases (ABGs) - Nursehealth.site

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Arterial blood gases

Interpretation

Presenter

RNO Farman

Ullah

General Nursing , ICU

Speciality

,Post RN

B.Sc,N

.

DEPT: Medical ICU

Dated: 26

th

May,2023

Objectives

ABGS Sampling

ABGS Normal values

ABGS acidosis status(acid) and ABGS Alkalosis status(base)

Compensation

Mixed Disorder or Mixed picture

Types of Therapy for blood gases

Quiz

ABGS

The gases present in the blood of artery. The test perform for ABGS

Is ABGS test. ABGS test performed by ABGS machine

ABGS TEST

An arterial blood gases analysis (ABGS) measure the balance of potential hydrogen, oxygen , bicarbonate and

corbondioxide

in blood to see how lungs and kidneys work.

The process of analysis and monitoring of arterial blood gas (ABG) is an essential part of diagnosing and managing the oxygenation status and acid–base balance of the high-risk patients, as well as in the care of critically ill patients in the Intensive Care Unit.

In 1957, John

Severinghaus

developed the first blood gas analyzer

.

ABGS Machine

ABGS sampling

Sites :

Radial artery

Brachial artery

Femoral artery

IF

Arterial line

inplaced

Or

Femoral sheath

inplaced

Blood will be draw from lines

Brachial artery

Radial artery

Femoral artery

Figure 1

Figure 2

Arterial line

Femoral sheath

Figure 1

Figure 2

Potential Pre analytical Errors

During preparation prior to sampling

Missing or wrong patient/sample identification;

Use of the incorrect type or amount of anticoagulant

dilution due to use of liquid heparin;

insufficient amount of heparin;

Inadequate stabilization of the respiratory condition of the patient; and

Inadequate removal of flush solution in arterial lines prior to blood collection.

During sampling/handling

• Mixture of venous and arterial blood during puncturing;

•Air bubbles in the sample. Any air bubble in the sample must be expelled as soon as possible after withdrawing the sample and before mixing with heparin or before any cooling of the sample has been done. An air bubble is a potential source of significant error and may seriously affect the pO2 value.

•Insufficient mixing with heparin.

During storage/transport

• Incorrect storage

• Hemolysis of blood cells

General Storage Recommendation

• Do not cool the sample.

• Sample analyze within 30 min.

• When analysis is expected to be delayed for more than 30 minutes, use of glass syringes and ice slurry is recommended.

During preparation prior to sample transfer

•Visually inspect the sample for clots.

•Inadequate mixing of sample before analysis.

Insufficient mixing can cause coagulation of the sample. It is recommended to mix the blood sample thoroughly by inverting the syringe 10 times and rolling it between the palms as shown in Figure 3. This prevents stacking (such as coins or plates) of red blood cells.

Figure 3

Correct method of mixing of the arterial sample with the anticoagulant in two dimensions to prevent stacking of red blood cells.

ABGS Syringes

There are two types syringes use

Modren

blood gases syringe

This syringe already heparinized with dry heparin and packed. should be checked

That how many IU/ML.

Normal range 50 IU/ML

Simple disposable Syringe

it is not heparinized . We should

take 0.05ml heparin then expelled heparin from 3cc syringe for heparinizing the syringe.

Figure 4

Modren

blood gases syringe

Modren

blood gases syringe

ABGS Normal

Rangesa

Analyzing three parameters are the most important while interpreting ABGS which are mentioned below.

(1) PH = 7.35 to 7.45

(2) CO2 = 35 to 45 mmHg

(3) HCO3 = 22 to 28

meq

/L

Spo2=95% to 100%

Po2 =80% to 100%

Step : 1

Acidosis

:

When PH reduces in ABGs from normal level (PH<7.35) is known as acidosis

PH

Alkalosis:

when PH increases in ABGs from normal level (PH>7.45) is known as

Alkalosis

PH

Step 2

Respiratory problems

When PH and CO2 inversely proportional to each other or in opposite direction if PH increases then CO2 will be reduced in ABGS and if PH reduces then CO2 will be increased in respiratory problems. (Absolutely lungs involved).

For example

Acidosis

normal

Respiratory Acidosis

PH=7.50

CO2=

20 HCO

3 =2

4 C

PH=7.

2 CO2=

6 HCO

3 =2

6 Respiratory Alkalosis

Alkalosis

Normal

Step 3

Metabolic problems

When PH and HCO3 directly proportional to each other or in same direction if PH increases then CHO3 will be increased in ABGS and if PH reduces then HCO3 will be reduced in metabolic problems (mainly kidneys involved).

For example

Acidosis

normal

Metabolic acidosis

PH=7.50

CO2=

40 HCO

3 =36

PH=7.21

CO2=

40 HCO

3 =1

4 Alkalosis

normal

Metabolic Alkalosis

Step 4

Compensation

Compensation is the mechanism by which the body copes with either acidosis or alkalosis

The main purpose of compensation is to normalize the PH of blood as persistent acidosis/alkalosis which causes damage to tissue and organs.

For example 1

(Respiratory problem with compensation)

Acidosis

Respiratory acidosis with

metabolic compensation

PH=7.59

CO2=

22 HCO

3 =14

PH=7.25

CO2=

55 HCO

3 =36

Alkalosis

Respiratory alkalosis with

metabolic compensation

Step 4

Example 2

Metabolic problems with compensation.

Metabolic acidosis with

Respiratory compensation

PH=7.57

CO2=

58 HCO

3 =38

Acidosis

PH=7.20

CO2=

20 HCO

3 =13

Metabolic alkalosis with

Respiratory compensation

Alkalosis

Step 4

There are two types of compensation

Partial

ompesation

Fully compensation

(1) Partial

compensation

:PH

will be increased or reduced from normal range (7.35 to 7.45)

for example

PH=7.55 Alkalosis

CO2=20

HCO3=12

(2) Fully

compensation

:PH

will be in normal range (7.35__7.40__ 7.45) .For example:

PH=7.43 Normal

C02=55

HCO3=40

Step 5

Mixed disorder or Mixed picture

Mixed picture is the mechanism in which both respiratory and metabolic problems will occur at a time.it means that both kidneys and lungs involved. focus should be on more problematic organ.