Phlebotomy Book- Chapter 10 Flashcards
dermal puncture is the preferred method for-
young patients (infants & very small children)
dermal puncture is preferred method in younger patients because-
the veins are very small, & it is difficult to find a vein large enough to withstand the vacuum in evacuated collection tubes
dermal puncture may also be used for- (3)
-elderly
-obese
-severely burned patients
dermal puncture takes less time, so it is more- (3)
-successful
-easy to perform
-less traumatic for children
dermal puncture may also be used as alternate method of blood collection for adults with -
difficult venipuncture procedures
patients who are obese or have thin skin are often candidates for-
dermal (capillary) puncture
The blood specimen obtained using dermal puncture is not entirely venous blood, instead, it is a mixture of- (4)
-Capillary blood
-Venous blood
-Arterial blood
-Interstitial fluid
capillary blood is higher in-
glucose
capillary blood is lower in- (3)
-electrolytes (sodium, potassium, chloride & calcium)
-total protein
-bilirubin making normal values (reference ranges) different
Dermal Puncture Preparation- (6)
-acquire & examine the requisition slip
-greet & identify the patient
-explain the procedure
-verify any dietary restrictions
-wash your hands
-put on gloves
main differences between venipuncture & dermal puncture- (2)
-site selection
-equipment assembled
when selecting a dermal puncture site, the skin should be-
warm, pink, & free from scars, cuts, rashes, or bruises
Sites to consider for dermal (capillary) puncture for children & adults- (2)
-use the distal region of the third or fourth finger of the hand, palmar surface of the finger, or sides of the fingertip instead of the middle of the finger
-warm the finger slightly to increase blood flow
Sites to consider for dermal (capillary) puncture for infants- (2)
-use the medial or lateral plantar surface of the heel, well away from the calcaneus (heel bone) (if calcaneus is punctured, it can cause osteomyelitis (bone infection))
-never perform a dermal puncture on the heel of an infant who has begun to walk
Sites to consider for dermal (capillary) puncture for infants less than 1 year old- (3)
-sides of the plantar surface of the heel are the sites of choice
-do not use the fingers because they are too small to maintain a safe distance from the bone during puncture
-If an infant has several old puncture sites, attempt to find an unused area
do not use these sites for dermal puncture- (3)
-Arch of the foot
-Back of the heel
-Plantar area (bottom surface, or sole) of foot
do not use the thumb or pointer fingerer dermal puncture because-
they are poor choices because the area is too thick & callused
do not use the pinkie for dermal puncture because-
the bones are closer to the surface, increasing the risk of bone puncture
actual depth of the puncture is slightly more than the lancet/device blade length because-
the pressure used to perform the puncture compresses the skin slightly
lancet devices are usually set at ____ for children over 8 & adults-
2.2 mm
slightly longer lancet depths may be needed for-
obese patients
puncture depth should never be greater than-
2mm
equipment needed for dermal puncture- (10)
-Requisition slip
-Alcohol prep pad
-Gauze pad
-Gloves
-Adhesive bandage or tape
-Sharps container
-Computer label
-Permanent marker or pen
-Lancet
-Microspecimen containers
steps for planning the puncture- (3)
-examine the fingers
-choose a finger for the puncture
-plan to cut across the fingerprint
select a puncture site that is warm & free from- (4)
-scars
-cuts
-rashes
-bruises
when making a puncture, plan to cut across the fingerprint, do not cut in the same direction as the fingerprint because-
blood tends to run in the prints or ridges instead of forming a rounded drop
steps in performing the puncture- (5)
-clean the site with alcohol
-allow to dry completely
-hold the finger in the proper position & stretch skin tightly
-position the lancet to cut across the fingerprint, rather than in the same direction as the fingerprint
-puncture the finger
improper technique during dermal puncture can cause-
bone infection, especially in infants
Do not use spring-loaded devices designed for glucose monitoring for dermal puncture because-
these lancets produce a smaller puncture & only 2-3 drops of blood
not allowing alcohol to dry before puncture will result in-
hemolysis of the blood due to contact with the alcohol
steps to perform dermal puncture- (4)
-assemble the equipment, considering the patient & puncture depth
-clean the site with an alcohol pad & allow the site to dry thoroughly
-hold the finger (or heel) with the skin stretched tightly
-use the lancet or puncture device according to the manufacturer’s direction to create the puncture
during collection, wipe away the first drop to avoid-
contaminating the specimen with tissue fluid
the first drop of blood contains- (2)
-interstitial fluid
-damaged tissue cells
after the next drop of blood has formed-
touch the open end (collection tube/scoop) of the microcollection container to the drop of blood
while collecting the blood, gently tap the container after each drop to ensure-
mixing with the anticoagulant, if present
do not “milk” the finger (massage or apply pressure moving toward the puncture site) because this will-
contaminate the specimen with interstitial fluid causing hemolysis or clotting
do not scrape the container against the skin while collecting blood because this may cause the blood to-
hemolyze or clot before it mixes with the anticoagulant in the collection container
it is critical to collect blood to the fill line, especially if-
the container has an anticoagulant
order of draw- (4)
-EDTA (lavender or pink)
-Heparin (green or light blue)
-Sodium Fluoride (gray)
-Nonadditive (red) or Serum Separator (gold)
complications of dermal puncture- (4)
-Infection
-Osteochondritis
-Osteomyelitis
-if microorganisms are present in the scar tissue from previous puncture
infections in dermal puncture-
puncturing through a previously punctured site
Osteochondritis-
inflammation of bone & cartilage from being punctured
osteomyelitis-
inflammation of bone marrow & adjacent bone from being punctured
collecting too much blood for dermal puncture can result in- (2)
-iatrogenic anemia
-exsanguination
a reason for drawing just the right amount of blood is-
the amount of additives in the microcollection containers are based on a specific quantity of blood
if too little or too much blood is drawn, the ratio of blood to additive is affected, which may cause- (2)
-the blood to clot
-affect test results
not all patients should have a bandage applied, small children tend to put their fingers in their mouths, this puts them at risk for-
swallowing or choking on the bandage
