Arterial Blood Gas

INTRODUCTION

• Interpreting an arterial blood gas (ABG) is a crucial skill for Physicians, Nurses, Respiratory Therapists, and other health care personnel. ABG interpretation is especially important in critically ill patients.

• The following six-step process helps ensure a complete interpretation of every ABG. In addition, you will find tables that list commonly encountered acid-base disorders.

• Many methods exist to guide the interpretation of the ABG. This discussion does not include some methods, such as analysis of base excess or Stewart's strong ion difference. A summary of these techniques can be found in some of the suggested articles. It is unclear whether these alternate methods offer clinically important advantages over the presented approach, which is based on the "anion gap."

What is ABG Test?

•An arterial blood gas (ABG) test measures oxygen and carbon dioxide levels in blood. It also measures body's acid base (pH) level, which is normally balanced when healthy.

Components of ABGs:

• PCO2 (ventilation) - Partial Carbon Dioxide

• PaO2 - (oxygenation) -Partial Oxygen

• HCO3- (metabolism) -Bicarbonate

• 02Sat - Oxygen Saturation

• pH-Acid/Base balance

BE- Base excess

• The arterial blood gas provides the following values:

⚫pH_Measurement of acidity or alkalinity, based on the hydrogen (H+) ions present.

•The normal range is 7.35 to 7.45

• PaO2_ The partial pressure of oxygen that is dissolved in arterial blood.

⚫The normal range is 80 to 100 mm Hg.

•Sa02_The arterial oxygen saturation.

•The normal range is 95% to 100%.

PaCO2 The amount of carbon dioxide dissolved in arterial blood.

•The normal range is 35 to 45 mm Hg.

•HCO3_The calculated value of the amount of bicarbonate in the bloodstream.

•The normal range is 22 to 26 mEq/liter

B.E. (Base Excess):

• The base excess indicates the amount of excess or insufficient level of bicarbonate in the system.

• The normal range is -2 to +2 mEq/liter.

⚫ (A negative base excess indicates a base deficit in the blood.)

INDICATIONS:

# Assess the ventilatory status, oxygenation and acid base status.

# Assess the response to an intervention.

# Regulate electrolyte therapy.

# Establish preoperative baseline parameters.

Arterial blood gas test results may show whether:

1. Your lungs are getting enough oxygen.

2. Your lungs are removing enough Carbon dioxide.

3. Your kidneys are working properly.

HOW TO DRAW AN ABG..???

Equipments

Site Selection

• Contraindication

Puncture procedure

• Post puncture procedure

Sample handling