8/2/2019 abg final

1/22

Sr.

no

SPECIFIC

OBJECTIVESDURATION CONTENTS

TEACHING

LEARNING

ACTIVITY

A V

AIDS BLACKBOARDACTIVITY EVALUATION

Define

Insertion of a needle/catheter into an artery for the

purposes of arterial blood sampling.

Blood is drawn anaerobically from a peripheral artery

(radial, brachial, femoral, or dorsalis pedis) via a single

percutaneous needle puncture, or from an indwelling

arterial cannula or catheter for multiple samples. Either

method provides a blood specimen for direct measurement

of partial pressures of carbon dioxide (PaCO2) and oxygen(PaO2), hydrogen ion activity (pH), total hemoglobin

(Hbtotal), oxyhemoglobin saturation (HbO2), and the

dyshemoglobins carboxyhemoglobin (COHb) and

methemoglobin (MetHb).

PURPOSE:

To evaluate the adequacy of ventilatory (PacO2)

acid-base (pH and PaCO2), and oxygenation (PaO2

and SaO2) status, and the oxygen-carrying capacity

of blood (PaO2, HbO2, Hb total, and

8/2/2019 abg final

2/22

dyshemoglobins).

The need to quantitate the patient's response to

therapeutic intervention and/or diagnostic evaluation

(e.g. oxygen therapy, exercise testing)

The need to monitor severity and progression of a

documented disease process.

8/2/2019 abg final

3/22

Sr.

no

SPECIFIC

OBJECTIVESDURATION CONTENTS

TEACHING

LEARNING

ACTIVITY

A V

AIDS BLACKBOARDACTIVITY EVALUATION

ANALYSIS

The following steps are recommended to evaluate arterial

blood gas values. They are based on the assumption thatthe average values are:

pH = 7.4

PaCO2 = 40 mm Hg

HCO3 = 24 mEq/L

1. First, note the pH. It can be high, low, or normal, as

follows:

pH > 7.4 (alkalosis)

pH < 7.4 (acidosis)

pH = 7.4 (normal)

A normal pH may indicate perfectly normal blood

gases, orit may be an indication of a compensated

imbalance. A compensated imbalance is one in

which the body has been able to correct the pH by

either respiratory or metabolic changes (depending

on the primary problem). For example, a patient with

primary metabolic acidosis starts out with a low

bicarbonate level but a normal CO2 level. Soon

afterward, the lungs try to compensate for the

imbalance by exhaling large amounts of CO2

8/2/2019 abg final

4/22

(hyperventilation).

As another example, a patient with primary

respiratory acidosis starts out with a high CO2 level;

soon afterward, the kidneys attempt to compensate

by retaining bicarbonate. If the compensatory

mechanism is able to restore the bicarbonate to

carbonic acid ratio back to 20:1, full compensation

(and thus normal pH) will be achieved.

2. The next step is to determine the primary cause of

the disturbance. This is done by evaluating the

PaCO2 and HCO3 in relation to the pH.

Example: pH > 7.4 (alkalosis)

a. If the PaCO2 is < 40 mm Hg, the primary

disturbance is respiratory alkalosis. (This

situation occurs when a patient hyperventilates

and blows off too much CO2. Recall that CO2

dissolved in water becomes carbonic acid, the

acid side of the carbonic acidbicarbonate

buffer system.)

b. If the HCO3 is >24 mEq/L, the primary

disturbance is metabolic alkalosis. (This situation

occurs when the body gains too much

bicarbonate, an alkaline substance. Bicarbonate

8/2/2019 abg final

5/22

is the basic or alkaline side of the carbonic acid

bicarbonate buffer system.)

Example: pH < 7.4 (acidosis)

a. If the PaCO2 is >40 mm Hg, the primary

disturbance is respiratory acidosis. (This

situation occurs when a patient hypoventilates

and thus retains too much CO2, an acidic

substance.)

b. If the HCO3 is

8/2/2019 abg final

6/22

The first set (1) indicates acute respiratory

acidosis without compensation (the PaCO2 is high,

the HCO3 is normal).

The second set (2) indicates chronic

respiratory acidosis. Note that compensation has

take place; that is, the HCO3 has elevated to an

appropriate level to balance the high PaCO2 and

produce a normal pH.

4. Two distinct acidbase disturbances may occur

simultaneously. These can be identified when the

pH does not explain one of the changes.

Example: Metabolic and respiratory acidosis

a. pH 7.21 decreased acid

b. PaCO2 52 increased acid

c. HCO3 13 decreased acid

This is an example of metabolic and respiratory acidosis.

8/2/2019 abg final

7/22

Sr.

no

SPECIFIC

OBJECTIVESDURATION CONTENTS

TEACHING

LEARNING

ACTIVITY

A V

AIDS BLACKBOARDACTIVITY EVALUATION

CONTRAINDICATIONS:

Contraindications are absolute unless specified otherwise.

Negative results of a modified Allen test (collateralcirculation test) are indicative of inadequate blood

supply to the hand' and suggest the need to select

another extremity as the site for puncture.

Arterial puncture should not be pertormed through a

lesion or through or distal to a surgical shunt (eg, as

in a dialysis patient). If there is evidence of infection

or peripheral vascular disease involving the selected

limb, an alternate site should be selected.

Agreement is lacking regarding the puncture sitesassociated with a lesser likelihood of complications;

however, because of the need for monitoring the

femoral puncture site for an extended period,

femoral punctures should not be performed outside

the hospital.

A coagulopathy or medium-to-high-dose

anticoagulation therapy (e.g. heparin or coumadin,

streptokinase, and tissue plasminogen activator but

not necessarily aspirin) may be a relative

contraindication for arterial puncture.

8/2/2019 abg final

8/22

Sr.

no

SPECIFIC

OBJECTIVESDURATION CONTENTS

TEACHING

LEARNING

ACTIVITY

A V

AIDS BLACKBOARDACTIVITY EVALUATION

SITES OF PUNCTURE

1. RADIAL ARTERY

The radial artery is most easily accessible medial to

the radial styloid process and lateral to the flexor

carpi radialis tendon, 2-3 cm proximal to the ventral

surface of the wrist crease

8/2/2019 abg final

9/22

2. BRACHIAL ARTERY

The brachial artery is best identified between the

medial epicondyle of the humerus and the tendon of

the biceps brachii in the antecubital fossa. It can be

felt higher in the arm in the groove between the

biceps and triceps tendons. The basilic vein and the

brachial nerve are located in close proximity

8/2/2019 abg final

10/22

3. FEMORAL ARTERY

The femoral artery is best identified in the midline

between the symphysis pubis and the anterior

superior iliac crest, 2-4 cm distal to the inguinal

ligament. The femoral artery is medial to the femoral

nerve and lateral to the femoral vein

Assessment of collateral circulation (modified Allen

test) If puncture of the radial artery is planned, a

modified Allen test should be performed

beforehand when feasible to assess the

collateral circulation. Although the anatomy of

the radial artery in the forearm and the hand

is variable, most patients have adequate

collateral flow should radial artery thrombosis

occur. The modified Allen test is performed

as follows.

Firm occlusive pressure is held on both the

radial artery and the ulnar artery (see the first

image below). The patient is asked to clench

the fist several times until the palmar skin is

8/2/2019 abg final

11/22

blanched (see the second image below), then

to unclench the fist. Overextension of the

hand or wide spreading of the fingers should

be avoided, because it may cause false-

normal results. The pressure on the ulnar

artery is released while occlusion of the radial

artery is maintained (see the third image

below). The time required for palmar capillary

refill is noted.

8/2/2019 abg final

12/22

POSITION

For radial artery blood sampling, the patient should

be in the supine position, with the arm lying at his or

her on a hard surface. The forearm should be

supinated and the wrist dorsiflexed at 40. A gauze

roll may be placed under the wrist to make the

patient more comfortable and to bring the radial

artery to a more superficial plane. Overextension of

the wrist is discouraged, because interposition of

flexor tendons may make the pulse difficult to detect.

For femoral artery blood sampling, the patient is

supine on a stretcher, and the patient's leg is placed

in neutral anatomic position.

For brachial artery blood sampling, the arm is placed

on a firm surface with the shoulder slightly abducted.

The elbow is extended, with the forearm in full

supination.

8/2/2019 abg final

13/22

Sr.

no

SPECIFIC

OBJECTIVESDURATION CONTENTS

TEACHING

LEARNING

ACTIVITY

A V

AIDS BLACKBOARDACTIVITY EVALUATION

COMPLICATIONS:

Hematoma

Arteriospasm

Air or clotted-blood emboli

Anaphylaxis from local anesthestic

Introduction of contagion at sampling site and

consequent infection in patient; introduction

of contagion to sampler by inadvertent needle

'stick.'

Hemorrhage

Trauma to the vessel

Arterial occlusion

Vasovagal response

Pain

8/2/2019 abg final

14/22

Equipment Needed:

A. Clean tray

a. Mackintosh and towel

b. Spirit

c. Betadine

d. Kidney tray

e. Disposal syringe 2-5 ml

f. Chittle forcep

g. Injection heparin

h. Disposable gloves

i. Cup with crushed ice

j. Laboratory requisition form

k. Label with date, time, IPD/OPD, patients

name etc..

B. Sterile tray

a. Bowl

b. Gauze piece

c. 23 or 25 gauze needle

d. Eye towele. Arterial catheter if any

8/2/2019 abg final

15/22

Sr.

no

SPECIFIC

OBJECTIVESDURATION CONTENTS

TEACHING

LEARNING

ACTIVITY

A V

AIDS BLACKBOARDACTIVITY EVALUATION

NURSING RESPONSIBILITY

1. Check the physicians order.

2. Identify the client and explain the procedure to the

client and his family including need of interventionand complications

3. Monitor vitals before and after the procedure.

4. Asses for sites of puncture

5. Obtain written consent from the patient.

6. Assure the patient that best care will be taken during

the procedure.

7. Inform the physician about the patients willingness.8. Check for the sterility of the equipments.

9. Collect all the necessary equipments near the bed of

the patient

STEPS IN PROCEDURE

1. Identify client and explain procedure to client in calm

tone of voice.

2. Prepare syringe with heparin:

a. Aspirate 0.5 ml sodium heparin (1000 U/ml)

into syringe from vial.

b. Withdraw plunger entire length of syringe and

8/2/2019 abg final

16/22

eject all heparin out of syringe.

3. Select safest and most accessible site for ABG

sample:

4. Perform Allens test. Have client make tight fist and

apply direct pressure to both radial and ulnar

arteries, When client opens hand, release pressure

over ulnar artery and observe color of fingers,

thumbs, and hand. Fingers should flush within 15

secondsa positive Allens test. If Allens test is

positive, use the radial artery.

5. Wash hands and put on gloves.

6. Palpate selected radial site with fingertips and

stabilize artery by slightly hyper-extending wrist.7. Use alcohol swab to clean in a circular motion the

area above the pulse.

8. Hold alcohol swab in fingers of one hand while

keeping a fingertip from the other hand on the

artery.

9. Insert needle with bevel up into artery at a 45

angle.10. Hold the needle and syringe still when blood

appears in the syringe.

11. Allow arterial pulsing to slowly pump 23 ml of

blood into heparinized syringe.

8/2/2019 abg final

17/22

12.When sample is collected, hold alcohol swab over

the puncture site and withdraw needle.

13. Apply pressure with the alcohol swab over the

puncture site for 5 minutes, or 10 minutes if the

client is on anticoagulant therapy or has a bleeding

disorder.

14. Inspect site for signs of complications

a. Bleeding

b. Change or disappearance of pulse

c. Color of hand

15.Remove gloves and wash hands.

16.Prepare sample for laboratory and send it:a. Expel air bubbles from syringe.

b. Label syringe with client identification.

c. Place syringe in cup of crushed ice.

d. Fill out requisition form,including amount of

oxygen the client is receiving (e.g.,2 liters O2

by nasal cannula,room air,70% on ventilator)

e. Note some laboratories also require a recentbody temperature.

8/2/2019 abg final

18/22

17.Review results of ABG sample and compare with

normal values:

a. pH 7.357.45, PaCO2 3545

b. PaO2 80100

c. SaO2 94%98%

18.Report ABG results to physician or qualified

practitioner and perform nursing measures

accordingly:

a. Respiratory acidosis

b. Respiratory alkalosis

DOCUMENTATIONWhen the blood gas results are delivered to the nurse, they

should be reported to the clients physician.

1. NURSES NOTES

The date and time of the ABG sampling

should be recorded in the narrative notes.

Also record the reason for the test, the resultsof the Allens test, the clients response to the

blood sampling, and any unusual

observations.

Note the route and amount of oxygen the

8/2/2019 abg final

19/22

client is receiving and any respiratory

assessment observations.

Record the condition of the puncture site prior

to the blood draw and after the blood draw.

Be sure to note the follow-up check on the

condition of the site.

2. LABORATORY REQUISTION FORM

Record the date and time of the sample, the clients

name and room number, the site the sample was

drawn from, and the amount and route of oxygen

delivery.

AFTER CARE

1. Replace all the articles

2. Send the specimen to the laboratory as early as

possible

3. Check the puncture site for complications

4. Review the results and inform physician

8/2/2019 abg final

20/22

Summary

Till now we have seen the definition, purpose,

contraindications, sites of withdrawal, complications, pre

procedure care, steps in procedure, documentation and

after care.

ASSIGNMENT

WRITE 3 NURSING DIAGNOSIS FOR A PATIENT

UNDERGONE ARTERIAL BLOOD GAS ANALYSIS.

8/2/2019 abg final

21/22

Sr.

no

SPECIFIC

OBJECTIVESDURATION CONTENTS

TEACHING

LEARNING

ACTIVITY

A V

AIDS BLACKBOARDACTIVITY EVALUATION

BIBLIOGRAPHY:-

1. Lewis, Heitkemper & Dirksen (2000) Medical Surgical

Nursing Assessment and Management of Clinical

Problem (7th

ed) Mosby, pg no. 2552-66.

2. Black J.M. Hawk, J.H. (2005) Medical Surgical

Nursing Clinical Management for Positive Outcomes.

(7th ed) Elsevier, pg no. 2441-54.

3. Brunner S. B., Suddarth D.S. The Lippincott Manual

of Nursing practice J.B.Lippincott. Philadelphia, pgno. 32051-59

4. Understanding medical surgical nursing, F A Davis 6thedition, elsieiver publication pg. no. 210-224.

5. www.trauma..org/systemtrauma.html

http://www.trauma..org/systemhttp://www.trauma..org/systemhttp://www.trauma..org/system

8/2/2019 abg final

22/22