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Don appropriate personal protective equipment (PPE) based on the patient’s signs and symptoms and indications for isolation precautions.
Strictly adhere to guidelines for hand hygiene, standard precautions, and site preparation to minimize the risk for a health care–associated infection.13
Draw specimens for a blood culture before administering antibiotics.
Label blood specimens immediately after collection and in the presence of the patient.11,13
Take extra care with a patient who takes medications that increase the risk for bleeding.13
Signs and symptoms of nerve injury to the arm include severe, unusual, or shooting pain; tingling; numbness; or a tremor. If the patient complains of any of these during venipuncture, withdraw the needle immediately.4
A blood culture specimen requires 20 to 30 ml1 of blood drawn at one time from one location. Blood culture specimens should be drawn when the patient is experiencing signs and symptoms of bloodstream infection, including fever or chills, and before the administration of antibiotics to increase the likelihood of obtaining a true-positive result. If the patient has been on antibiotics at the time cultures are obtained, the laboratory should be notified because an additive can be applied to the culture medium to negate the antibiotic's effect.17 Typically, two sets of blood cultures are ordered, each with one aerobic bottle and one anaerobic bottle. Orders regarding the spacing of the specimens may vary among practitioners and organizations.
Drawing at least two sets of blood cultures and obtaining cultures from two different sites is important.17 If one of the cultures produces bacteria and the other culture does not, assuming that the bacteria in the first culture may be a contaminant and not the infecting agent is safe.17 When both cultures grow the infecting agent, bacteremia exists and is a result of the organism that is growing in the culture.
Caution should be taken to avoid contaminating the patient's skin or equipment to minimize the risk of false-positive test results, which can lead to inappropriate antibiotic use. False-positive results may expose patients to additional laboratory tests and increased length of stay.
Blood culture specimens are usually drawn using either a needle and syringe or a vacuum extraction blood-sampling system that draws blood into vacuum-sealed test bottles. In both cases, a hollow-bore needle is inserted into the lumen of a vein to obtain the specimen. Straight needles from extraction-collection systems are not used with blood culture bottles. Instead, winged-butterfly needles with a short length of tubing may be approved by the organization for use.
The correct amount of blood required by the laboratory must be extracted into each bottle to ensure accurate results and decrease the patient's risk of anemia.11 If more than one specimen is to be drawn during a single venipuncture, specimens for blood cultures should be drawn first to maintain asepsis and prevent contamination with additives from laboratory tubes.
Because limited venous access may be a life-threatening complication of venipuncture, maintaining the vein's integrity is essential. A patient with veins that may collapse or become injured from the vacuum pressure may require an alternative method of specimen collection. In addition, a patient whose veins may be difficult to locate because of unusual anatomy, trauma from repeated phlebotomy, or edema may also require an alternative method of specimen collection. Transillumination and ultrasonography may be available to aid with detecting veins that are otherwise impalpable or difficult to see.8
Tourniquets should be used with caution. To obtain valid results, the tourniquet should not be applied for longer than 1 minute.11 Prolonged tourniquet application can cause stasis and hemoconcentration.11 Infection-control standards require that tourniquets be single-use.10 Contamination from Staphylococcus aureus with reused tourniquets is common.21
Venipuncture can be painful, and a patient may experience anxiety or fear before the procedure. For some patients, particularly children, just the appearance of a needle is frightening. A calm approach and skilled technique may help limit the patient's aversion to venipuncture. The application of a vapocoolant spray has been shown to be effective in reducing pain during venipuncture.2 Anxiety may be eased by communicating with the patient about how to help relieve his or her concerns.
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Rationale: Resin can be added to the culture medium to negate the antibiotic effect.
If cultures are to be performed while the patient is on antibiotics, take the specimen shortly before the next antibiotic dose.17
Replace latex equipment with nonlatex equipment if the patient has a latex allergy.
Rationale: A low, supported position and an empty mouth
3 reduce the risk of injury to the patient if he or she experiences lightheadedness, faints from vagal stimulation, or experiences a seizure.
Do not draw blood if there is a discrepancy between the laboratory requisitions or labels and the patient's identity.3
Rationale: Proper patient positioning helps stabilize the arm.
Avoid the use of a tourniquet, if possible.
Consult with the clinical team leader per the organization's practice to stop the IV infusion for 2 minutes before obtaining the blood specimen as applicable.5
Rationale: A tourniquet blocks venous return to the heart from the arm, causing the veins to dilate for easier assessment.
A tourniquet should not be used on a patient who has a history of bleeding, is easily bruised, has fragile skin, or has diminished circulation; however, if a tourniquet must be used, apply it loosely.
Do not keep the tourniquet on the patient longer than 1 minute.11 Prolonged tourniquet application causes stasis, hemolysis, and hemoconcentration because of changes in the vascular endothelium from increased venous pressure and hypoxia.11
Rationale: A healthy vein is elastic and rebounds on palpation. A thrombosed vein is rigid, rolls easily, and is difficult to puncture.
Do not use a vein that feels rigid or cordlike or one that rolls when palpated.
Rationale: Making a fist facilitates the distention of veins by forcing blood up from the distal veins. Vigorously opening and closing the fist may cause pseudohyperkalemia.
Rationale: Warming increases arterial blood flow, making veins more prominent.
If unable to locate an acceptable vein after reapplying the tourniquet, use transillumination or ultrasonography, per the organization's practice, to help locate an appropriately perfused vein before attempting venipuncture.
Do not select a vein on the ventral surface of the wrist.9
Rationale: Combining systems may cause injury to the patient or yield incorrect test results because of hemolysis, needle disengagement, or inadequate tube filling. Incompatibility of components may cause failure of the process.
Do not use pediatric culture bottles for adult blood samples because smaller volumes diminish the yield of pathogens.
Rationale: Hemolysis may disrupt specimens drawn after blood culture specimens are drawn during the same venipuncture. Needles that are 23 G or smaller increase the risk of hemolysis.
21 If the needle is too large for the vein, it tears the vein and causes bleeding.
Keep the needle hub and the connection sites sterile.
Vacuum-extraction system sheathed needles are considered sharps that are associated with needlestick injuries, and they must be disposed of in a sharps container that is within arm's reach and is large enough to allow disposal of the entire device without detaching the needle.21 The sheathed needle's flexible cover prevents blood from flowing when the needle is not engaged in a vacuum tube; however, the sheath does not prevent a needlestick injury if a finger inadvertently enters the collection barrel.
Use a new collection barrel for each patient. Do not detach the needle from the collection barrel for disposal after use.21
Rationale: Puncturing the stopper before the needle is in the vein causes the tube to lose its vacuum.
Do not contaminate the top of the bottle after it is prepared with alcohol.
Rationale: The rubber-sheathed needle housed in the collection barrel is used to puncture the rubber top of the vacuum bottle. When the rubber top is punctured, the vacuum in the bottle extracts blood from the syringe.
Do not contaminate the transfer device or the top of the bottle after it is prepared with alcohol.
Use chlorhexidine cautiously because it may cause skin irritation and chemical burns in infants less than 2 months old or infants with compromised skin integrity (premature infants).10
If contamination occurs, discard the needle and the collection barrel or syringe in a sharps container and prepare a new venipuncture set.
Rationale: Gently stretching the patient's skin helps stabilize the vein and prevents it from rolling during needle insertion.
Rationale: The smallest and sharpest point of the needle should puncture the skin first to reduce the chance of penetrating the sides of the vein during insertion. Keeping the bevel up causes less trauma to the vein. Entering the skin distal to the vein prevents unanticipated vein puncture, which may result in inadequate blood specimen retrieval and hematoma.
Rationale: Inserting the needle slowly prevents puncture through the opposite side of the vein.
When using the butterfly method, collect the aerobic sample first and then collect the anaerobic sample. There is air in the butterfly tube that can expose the sample, so the opposite collection order is used for this method. Be sure to label the samples to reflect the order of collection.
Observe the rapid flow of blood into the bottle. Failure of blood to appear indicates that the vacuum is lost or that the needle is not in the vein. Avoid overfilling, which may cause a false-positive result.
If an insufficient amount of blood is drawn, inoculate the aerobic culture bottle with the required amount and then inoculate the anaerobic culture bottle with the remaining volume of blood.5
Keep the bottles upright to prevent a backflow of broth into the patient's vein.
Blood does not flow out of the collection barrel needle when it is detached from the bottles because the rubber sheath stops the flow of blood.
Rationale: Releasing the tourniquet before filling the last specimen tube reduces bleeding at the site when the needle is withdrawn.
Rationale: Applying pressure over the needle can cause discomfort and injury. Carefully removing the needle minimizes discomfort and vein trauma.
Rationale: Direct pressure minimizes bleeding and prevents hematoma formation. A hematoma may cause compression and nerve injury.
For a patient who has a bleeding disorder or is undergoing anticoagulant therapy, hold pressure for several minutes, as needed, until the bleeding stops.
Do not use a cotton ball or a rayon ball when applying pressure because of the potential for dislodging the platelet plug at the venipuncture site.3
Rationale: Applying gauze with tape or a bandage keeps the venipuncture site clean and controls any final oozing.
Instruct the patient not to bend his or her arm.
Carefully evaluate the patient for the potential for venous collapse when using a syringe barrel that is 10 ml or larger.21 Consider that young children, older adults, and those who have received treatments that are damaging to the veins may not be able to withstand high pressure or may require a smaller syringe barrel.
Rationale: Releasing the tourniquet before the last of the blood is drawn reduces bleeding at the site when the needle is withdrawn.
Rationale: Applying gauze with tape or a bandage keeps the venipuncture site clean and controls oozing.
Rationale: Transferring from the syringe alters the bottle's anaerobic environment. If the bottle and syringe are held upright, air near the syringe plunger should not enter the anaerobic culture bottle.
After skin antisepsis, the volume of cultured blood is the next most important variable affecting the sensitivity of detection of bacteria and fungi in the blood.
Rationale: Discarding the collection barrel, needle, and tubing prevents cross-contamination from needlesticks and contact with blood.
Do not recap needles or attempt to remove the needle from the collection barrel.15
Rationale: Unless ordered by the practitioner or per the laboratory's practice, blood cultures should be obtained from at least two separate blood draws on the same day or consecutive days and with two separate site preparations.
Rationale: Mixing gently blends the medium and the blood.
Rationale: Decontamination prevents cross-contamination and reduces the risk for exposure to blood-borne pathogens.
Rationale: Documenting the patient's response allows for improved care and planning for future venipunctures.
*In these skills, a "classic" reference is a widely cited, standard work of established excellence that significantly affects current practice and may also represent the foundational research for practice.
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