Chapter 13

• Arterial blood is rich in both oxygen and electrolytes.
• The absolute amount of oxygen is expressed as the partial pressure of oxygen.
• The carbon dioxide level is expressed as the partial pressure of carbon dioxide.
• ABGs measure the gas-exchange ability of the lungs and the buffering capacity of the blood.
• A lower-than-normal Po2 and a higher-than-normal Pco2 indicate that gas exchange in the lungs is impaired.
• Abnormal values mean that the body’s tissues are not getting adequate oxygen.
• Normal blood pH is 7.35to7.45.
• A lower pH indicates acidosis.
• a higher pH indicates alkalosis.
• The volume of blood required determines the syringe size; available syringe volumes range from 1 to 5 mL.
• The typical collection needle is usually 21 or 22 gauge.
• The 1-inch needle is used for either the brachial or the radial artery.
• The 11⁄2 inch needle is used for the femoral artery.
• Use a solution of sodium heparin with a concentration of 1000 U/mL.
• Use 0.05 mL of heparin solution for each milliliter of blood to be drawn.
• Luer Tip This plastic tip covers the syringe top after you have

  removed the needle.
• Collateral circulation is tested using the modified Allen test.
• the region distal to the collection site should have collateral

  circulation, meaning that it receives blood from more than one artery.
• The ulnar artery provides collateral circulation to the hand.
• Radial artery small size is a disadvantage in patients with low cardiac output because it is hard to locate.
• The brachial artery is large; therefore, it is easy to palpate and puncture.
• Nevertheless, the brachial artery has important disadvantages. It is deep and is close to the median nerve.
• The femoral artery is the largest artery used.
• Femoral it has poor collateral circulation.
• Femoral artery it is a difficult site to keep aseptic.
• Alternative sites in adults include the dorsalis pedis artery in the foot.
• In infants, the umbilical artery and scalp artery are used.
• When puncturing the dorsalis pedis, the posterior tibial must be

  checked for an adequate pulse.
• Arteriospasm, the spontaneous constriction of an artery in response to pain.
• Embolism, or blood vessel obstruction, due to an air bubble or dislodged clot in the artery.
• Hematoma, resulting from inadequate pressure on the site.
• Hematoma, This is more likely in elderly patients, whose artery walls are not as elastic and thus not as likely to close spontaneously.
• Hemorrhage. This is more likely in patients who have coagulation disorders or are receiving anticoagulant therapy
• Contaminants are easily carried to the rest of the body without

  encountering the immune system.
• Nerve damage, caused by inadvertent contact with a nerve.
• Thrombosis, or clot formation, within the artery.
• Samples collected in a plastic syringe are not iced, and must be analyzed within 30 minutes of collection.
• Samples collected in a glass syringe may be iced-5-to-10minutes if they are not to be delivered to the laboratory within.
• Iced samples must be delivered within 1 hour.
• Ice should not be used if the sample is being tested for potassium because lower temperatures affect those levels.