- Is also referred to as hct, PCV or Crit.
- Refers to the % or ratio of red blood cells in plasma.
- When serum is centrifuged, white blood cells and platelets rise to the top (this is referred to as a ‘buffy coat’). The red blood cells are heavier and pack to the bottom, thus the reason for the term PVC meaning packed cell volume.
- Is useful only if the hydration of the patient is normal.
- There is no special preparation of the patient.
- Can be obtained by capillary blood (finger or heel stick) or venipuncture.
- If obtained through capillary blood, discard the 1st drop and then fill the capillary tube.
- Capillary values may be 5-10% higher than venipuncture values.
- Values are also increased at high altitudes.
- Be sure not to squeeze the tissue to obtain capillary blood, it adds tissue fluids and dilutes the sample.
- Hematocrit is usually about three times higher than the hgb, in the patient with both a normal red blood cell count and hgb.
Decreases, especially in the last trimester as serum volume increases
Up to 60%
Varies with age
- Any decrease in the volume of plasma causes an increase in hematocrit, even though the red blood cell count has not increased. An example is the patient with a burn, here plasma or fluid may be lost from the vascular space making the blood more concentrated thus hct may be as high as 60-65%.
- If the patient’s hydration status is normal an increase may indicate a true increase in red blood cells (polycythemia).
Possible Nursing Diagnosis and Interventions:
- Fluid volume deficit r/t elevated hct.
- Determine if the increased hct is related to a decreased plasma volume or a true increase in red blood cells.
- If there is a lack of volume, an increased oral intake or parenteral fluid replacement may be ordered.
- Risk for Injury r/t possible formation of venous thrombi.
- If there is an increase in red blood cells, an increase in fluids may aid to decrease blood viscosity. (See also Red Blood Cell Count).
- Here the blood becomes more viscous making the patient susceptible to formation of venous thrombi.
- Therefore it is important to maintain adequate hydration.
- Example: 2000 mL per day for an adult.
- HOWEVER be sure to assess your patients overall status carefully, patients with heart defects and chronic lung disease may be nearing a state of congestive heart failure!
- It is important patients not become dehydrated. Consider this when NPO is ordered for extended periods of time.
May be due to:
- Overhydration, which increases the plasma volume.
- Or a true decrease in red blood cells (more common cause)
- Hct is important in assessing the magnitude of blood loss.
- Hct drawn right after a massive blood loss will probably be normal. Why? Both plasma and RBCs have been lost in equal proportion.
- A few hours after the bleeding episode - the plasma volume usually returns to normal due to a shift of some interstitial fluid into the plasma/vascular space (provided the patient has adequate fluid balance). The hct will be low because it will take about eleven days for new mature RBCs to replace the RBCs.
- ***Always interpret hct in relation to the time the sample is drawn and to the probable hydration status of the client at the time.
Possible Nursing Diagnosis and Interventions:
- Risk for fluid volume excess.
- Is where low hct reflects an increased plasma volume.
- Assess for signs and symptoms of excess fluid.
- Decrease fluid intake.
- Strict I & O (as all I & O should be strict!)
- Risk for activity intolerance related to loss of blood.
- Assess for paleness of the skin and conjunctiva.
- Patient’s will often have a normal BP. However, if there’s not enough fluid to shift from extravascular to intravascular abd replace the loss of blood, the BP falls and signs of shock may be noted.
- If the loss isn’t severe the pulse may give a clue to the amount of blood loss. To assess the pulse, perform the ‘tilt test,’ have the patient sit up and the pulse will increase. The pulse may increase even more with exercise. These increases occur because the O2 carrying capacity of the blood is decreased. With a hct as low as 28% the heart rate may increase, even at rest.
- Assess for signs of continued bleeding
- Assess for occult (hidden) blood.
- Monitor pulse before and after activity.
- Consider weakness and fatigue on exertion when planning activities.
- Ask not only the reason for low hct, but whether it is acute or chronic.
- The patient with acute low hct related to sudden blood loss may quickly develop signs and symptoms of shock.
- The patient with chronic low hct, as low as 18-20%, may show few symptoms because the body has had time to adjust.
- Example: The renal dialysis patient (low hct is partially related to the lack of erythropoietin normally made by the kidneys).
- Example: The patient with sickle cell anemia (here the RBCs have an abnormal hgb that decreases the life of the cells)
- Alteration in nutritional requirements or iron and protein.
- The patient with low hct needs adequate iron and protein.
- The iron is needed by the bone marrow to create new RBCs.
- Adequate protein is needed to produce protein hormones, particularly erythropoietin.
- Provide foods high in iron and protein such as liver, egg yolk, lean beef and prune juice.
- Heme iron, found in animal products is readily available for absorption.
- Nonheme iron, found in all other sources contains dietary inhibitors that decrease absorption.
- Knowledge deficit related to iron supplements.
- It may be difficult to increase iron intake by diet alone, therefore iron supplements may be prescribed.
- Supplements may be prescribed for up to three months after hct returns to normal, allowing the body to build up a reserve.
- Teach patient’s taking iron supplements the following:
- Supplements may cause the feces to turn a dark greenish-black.
- Supplements may cause constipation.
- Iron is best absorbed in an acid stomach. Take with vitamin C (ascorbic acid) to increase absorption. However, if unable to tolerate take with food.
- Iron and antacids should not be taken together. Antacids create an alkaline stomach environment and decrease absorption.
- Tetracycline and cholesterol-lowering drugs decrease absorption.
- ***Iron products are the leading cause of accidental poisoning in children.
- Risk for infection.
- Protect from infection. Immunologic defenses of the anemic, iron deficient patient are deceased and predisposes them to infection
- Alteration in comfort.
- Fatigue and weakness may be present.
- The patient is easily chilled. Provide blankets and warm clothing.
- Risk for alteration in breathing pattern.
- Dyspnea can develop with a very low hct because the amount of oxygen to the tissues is reduced (ABGs remain normal).
- The administration of oxygen does not solve the problem (it’s more an issue of not having enough RBCs to transport oxygen). Transfusion of RBCs would be more effective.
- Oxygen may be given for symptomatic.
- Risk for injury related to use of blood tranfusions.
- As with all who receive blood, this patient is at risk for allergic reactions and transmission of viruses.
- A hct less than 25-35% may receive an order for blood (probably packed cells).
- A patient going to surgery should not have a hct less than 30%, therefore patient’s may receive blood preoperatively.
- A unit of whole blood or packed cells, raises the hct about 3% in an adult.