Arterial blood gas sampling and interpretation techniques

¶ … Arterial Blood Gas Samples

Instructions for the Sampling of Arterial Blood for Blood Gas Analysis

This document provides the procedure for the drawing of arterial blood from human patients for use in the analysis of blood gasses.

Audience

This document is intended to provide proper and safe steps in the procedure used by respiratory therapists, phlebotomists, nurses and doctors for the procurement of human blood from extremity arteries for subsequent analysis of blood gases (Browning 1989).

Topics Covered

This document covers recommended clinical practice for the sampling of arterial blood (Bruck1985). Because the nature of this procedure uses human clinical subjects and a biohazardous substance, human blood, significant explanation of safety and best clinical practice are covered in the information. Topics covered include:

Safety Guidelines

Clinical Practice Guidelines

Personnel Requirements

Recommended Equipment

Site Selection

Procedure

VII. Complications

VIII. Contraindications

I. Safety Guidelines

Blood is considered a toxic and/or pathogenic substance; individuals performing arterial puncture should be trained in proper syringe preparation, site determination, puncture technique, sample acquisition, storage and disposal of blood specimens, and postsampling care of puncture site. The following guidelines are required for safe arterial punctures and handling of blood

1. Guidelines published by the Centers for Disease Control (3,4) must be followed in all circumstances involving blood or blood-contaminated devices.

2. Prior to a single puncture, the site should be cleaned and made aseptic (1,7,8)

3. Blood specimens, needles, and syringes must be disposed of in appropriate hazardous waste or biohazard containers.

4. Needle sticks are the most frequent source of transmission of blood-borne diseases and all personnel handling needles should be trained in proper technique to avoid needle sticks.(19-20)

5. Needles used for blood sampling should be resheathed only with a technique that utilizes one-hand that prevents access to the sharp point.

6. The needle should removed from the syringe and the syringe capped when not in use.

7. Gloves do not protect from needle punctures but should be worn to prevent splashing of blood on breached skin.

II. Clinical Practice Guidelines

Patients should be sampled only with express clinical orders by a licensed practicing physician. The purpose of the test is to provide a viable blood specimen for measurement of partial pressure of CO2, O2, pH, hemoglobin, oxyhemoglobin saturation, and syshemoglobin carboxyhemoglobin and methemoglobin.

Oxygenated blood is drawn without exposing the fluid to air from a peripheral artery (radial, brachial, femoral, or dorsalis pedis) through a single needle puncture.(1-8)

III. Personnel Requirements

Arterial blood sampling should be performed only under the direction of a qualified physician.

Persons responsible for obtaining the specimen should have a high school education plus training in sampling arterial blood, and the associated hazards associated with blood and bodily fluid handling. .

IV. Recommended Equipment

The following list represents the general equipment necessary to perform a safe arterial blood draw:Figure 1: Properly Stocked Arterial Blood Draw Tray (Molnlycke Corporation)

1. Well fitting sterile latex or vinyl gloves

2. Sterile plastic low diffusibility syringe with needle

3. Heparin anticoagulant dolution

4. Antiseptic solution

5. Sterile gauze squares

6. Puncture resistant container

7. Needle disposal vessel

8. Syringe cap

9. Container of ice and water

10. Patient label corresponding to facility labeling procedure.

III. Site SelectionFigure 2: Diagram of radial and brachial artery locations (13)

Site selection is critical to safety and success in drawing arterial blood. It is possible to draw a sample from a radial, brachial, or femoral artery, the femoral artery is linked to higher rates of hematoma and infection and should be used only as a last resort. The pulse in both the radial and brachial arteries is easier to palpate and access.

Avoid brachial sites in obese patients because of the difficulty in attaining hemostasis.

IV. Procedure

The procedure varies from patient to patient depending on individual pain tolerance, accessibility of arteries and contraindications. The general procedure is detailed below:

1. Inform the patient that drawing blood from an artery may cause a burning sensation. Enlist cooperation in remaining still despite the discomfort until the procedure is completed.

2. Help the patient into a position that's comfortable for him and provides the best access to the identified draw site.

3. Turn the patient's palm face up and mildly hyperextend the wrist, using a small rolled towel under the joint to maintain the position. This extension moves the radial artery closer to the skin's surface, improving the palpation of the pulse and arterial distention.