Dermal Puncture

Laser lancets (Lasette Plus, Cell Robotics International, Inc., Albuquerque, NM)

- are available for clinical and home use, and are approved by the Food and Drug Administration (FDA) for adults and children older than 5 years. - lightweight, portable, battery-operated device eliminates the risks of accidental punctures and the need for sharps containers.

Microgard closure

- is removed by twisting and lifting.

laser light

- penetrates the skin 1 to 2 mm, producing a small hole by vaporizing water in the skin. - creates a smaller wound, reduces the pain and soreness associated with capillary puncture, and allows up to 100 µL of blood to be collected

BD Microtainer Contact-Activated Lancet (Becton Dickinson)

is designed to activate only when the blade or needle is positioned and pressed against the skin.

concentration of glucose

is higher in blood obtained by dermal puncture.

major vascular area of the skin

is located at the dermal subcutaneous junction

Warming the Site

- This is primarily required for patients with very cold or cyanotic fingers, for heelsticks to collect multiple samples, and for the collection of capillary blood gases. - dilates the blood vessels and increases arterial blood flow.

Hemolysis

is more frequently seen in samples collected by dermal puncture than it is in those collected by venipuncture.

povidone-iodine

is not recommended for dermal punctures because sample contamination may elevate some test results.

dermal puncture

is the method of choice for collecting blood from infants and children younger than 2 years

swollen or previously punctured site

is unacceptable because the increased tissue fluid will contaminate the blood sample.

1. callused 2. scarred 3. bruised 4. edematous 5. cold or cyanotic 6. infected 7. previous puncture sites (can easily introduce microorganisms) 8. side of a mastectomy

Areas selected for dermal puncture should not be:

Occupational Safety and Health Administration (OSHA) required safety devices

All devices must have it that retract and lock after use to prevent reuse and accidental puncture.

arterial pressure

Because of it the composition of this blood more closely resembles arterial rather than venous blood.

1. capillaries 2. arterioles 3. venules

Blood collected by dermal puncture comes from the:

-arterial and venous blood -interstitial and intracellular fluids

Blood collected by dermal puncture is a mixture of what blood? and may contain small amounts of?

True

By documenting that the sample was collected by dermal puncture, the health-care provider can consider the collection technique when interpreting results.

larger amount of blood required such as some coagulation studies that require - plasma - erythrocyte sedimentation rates - blood cultures

Certain tests may not be collected by dermal puncture:

● Burned or scarred patients ● Patients receiving chemotherapy who require frequent tests and whose veins must be reserved for therapy ● Patients with thrombotic tendencies ● Geriatric or other patients with very fragile veins ● Patients with inaccessible veins ● Obese patients ● Apprehensive patients ● Patients requiring home glucose monitoring and point-of-care tests

Dermal puncture may be required in many adult patients, including:

WBC and CBG

Excessive crying may affect the concentration of:

1. Causes a stinging sensation for the patient 2. Contaminates the sample 3. Hemolyzes RBCs 4. Prevents formation of a rounded blood drop because blood will mix with the alcohol and run down the finger

Failure to allow the alcohol to dry:

True

Failure to place puncture devices firmly on the skin is the primary cause of insufficient blood flow. One firm puncture is less painful for the patient than two "mini" punctures.

True

Having the parents present can provide emotional support and help enlist the child's cooperation.

Excessive squeezing of the puncture site ("milking") ● Newborns have increased numbers of red blood cells (RBCs) and increased RBC fragility ● Residual alcohol at the site ● Vigorous mixing of the microcollection tubes after collection

Hemolysis may occur in dermal puncture for the following reasons:

3 to 5 minutes

How long does it take covering the site to effectively warm?

5-10 times

How many times anticoagulated tubes gently inverted?

held horizontally

How to prevent the introduction of air bubbles in capillary tubes and micropipettes while being filled?

Heel

is used for dermal punctures on infants younger than 1 year because it contains more tissue than the fingers and has not yet become callused from walking.

42°C

In what temperature moistening a towel with warm water?

2.5 mm

Incision widths vary from needle stabs to

flea

Microhematocrit capillary tubes and a micropipette for capillary blood gases with metal filing called a

* seated or lying down * hand supported on a firm surface * palm up * fingers pointed downward

Patient Position

1. severely dehydrated 2. have poor peripheral circulation 3. have swollen fingers

Patients that are not possible to obtain a satisfactory sample by dermal puncture:

arch

Punctures should not be performed in other areas of the foot, and particularly not in the

1. nerves 2. tendons 3. cartilage

Punctures should not be performed in other areas of the foot that may cause damage to

low blood flow

Removal of the lancet before the puncture is complete will yield a

True

Select the puncture device that will safely provide the appropriate volume of blood to perform the required tests.

2.5 mm

Sufficient blood flow should be obtained from incision widths no larger than

10 minutes

The site should not be warmed for no longer than how many minutes or test results may be altered?

1. age of the patient 2. the amount of blood 3. sample required 4. the collection site 5. puncture depth

The type of device selected depends on the:

1. Unistik 2 Comfort for delicate skin 2. Unistik 2 Normal for normal skin/general use 3. Unistik 2 Extra for tougher skin/larger sample 4. Unistik 2 Super for multitest situations and optimal blood flow 5. Unistik 2 Neonatal for heelsticks on newborns

Unistik 2 lancets range from:

True

Use of glass capillary tubes is not recommended.

1. bilirubin 2. phosphorus 3. uric acid 4. potassium.

Use of povidone-iodine is not recommended for dermal punctures because sample contamination may elevate some test results, including:

• Use the medial and lateral areas of the plantar surface of the heel. • Use the central fleshy area of the third or fourth finger. • Do not use the back of the heel. • Do not use the arch of the foot. • Do not puncture through old sites. • Do not use areas with visible damage. • Do not use fingers on newborns or children younger than 1 year. • Do not use swollen sites. • Do not use earlobes. • Do not use fingers on the side of a mastectomy

What to do and not to do:

arterial blood gases (ABGs)

With the exception of it, very few chemical differences exist between arterial and venous blood.

1. lengths 2. depths

a variety of skin puncture devices are commercially available, in varying:

Rotating the hand 90 degrees

allows the phlebotomist to clearly see the blood drops without placing himself or herself in an awkward position and produces adequate blood flow.

Unistik 2 (Owen Mumford, Inc, Marietta, GA) safety lancets

are available in five versions with varying needle gauges and penetration depths.

Tubes protected by plastic sleeves and selfsealing tubes

are available to prevent breakage when collecting samples and sealing the microhematocrit tubes

BD Quikheel Lancets

are color-coded heelstick lancets made specifically for premature infants, newborns, and babies

lancets

are color-coded to indicate lancet puncture depths.

Correct collection techniques

are critical because of the smaller amount of blood that is collected and the higher possibility of sample contamination, microclots, and hemolysis.

Tenderfoot and Tenderlett devices

are designed for heel and finger punctures, respectively.

Microtainer tubes

are designed to hold approximately 600 µL of blood.

BD Microtainer tubes with BD Microgard closures

are designed to reduce the risk of blood splatter and blood leakage.

Capillary tubes

are frequently referred to as microhematocrit tubes, are small tubes used to collect approximately 50 to 75 µL of blood for the primary purpose of performing a microhematocrit test.

concentrations of potassium, total protein, and calcium

are lower.in blood obtained by dermal puncture.

Finger punctures

are performed on adults and children over 1 year of age.

1. Alcohol pads 2. gauze 3. sharps containers

are required for the dermal puncture just as they are for the venipuncture.

Microcollection tubes

are slanted down during the collection, and blood is allowed to run through the capillary collection scoop and down the side of the tube.

Plain tubes

are used when the test is being performed on blood from a lavender stopper ethylenediaminetetraacetic acid (EDTA) tube.

posterior curvature

back of the heel

plantar

bottom surface of the heel

ecchymoses

bruising

dermal

capillary or skin

Residual alcohol

causes rapid hemolysis that can alter test results for certain analytes.

1. age 2. size

choice of a puncture area:

● Locating superficial veins that are large enough to accept even a small-gauge needle is difficult in these patients, and available veins may need to be reserved for intravenous therapy. ● Use of deep veins, such as the femoral vein, can be dangerous and may cause complications including cardiac arrest, venous thrombosis, hemorrhage, damage to surrounding tissue and organs, infection, reflex arteriospasm (that can possibly result in gangrene), and injury caused by restraining the child. ● Drawing excessive amounts of blood from premature and small infants can rapidly cause anemia, because a 2-pound infant may have a total blood volume of only 150 mL. ● Certain tests require capillary blood, such as newborn screening tests and capillary blood gases.

collecting blood from infants and children younger than 2 years for the following reasons:

Microcollection containers

color-coded to match evacuated tube colors and include amber containers for light-sensitive analyte testing.

fifth finger

decreased tissue

Tenderfoot

for preemies

Tenderlett

for toddlers, juniors, and adults

1/2 inch away from the puncture site

frequently produces better blood flow than pressure very close to the site.

Tubes

have a wider diameter, textured interior, and integrated blood collection scoop to enhance blood flow into the tube and eliminate the need to assemble the equipment

calcaneus

heel bone

red band tubes

heparinized

0.35 to 1.6 mm

in a newborn, can range from below the skin from:

0.35 to 3.0 mm

in an adult, can range from below the skin from:

index finger

increased nerve endings

Warming the site before sample collection

increases blood flow as much as sevenfold, thereby producing a sample that is very close to the composition of arterial blood.

heel warmer

is a packet containing sodium thiosulfate and glycerin that produces heat when the chemicals are mixed together by gentle squeezing of the packet

the depth of the puncture

is actually much less important than the width of the incision

Blood smears used for the WBC differential and the examination of RBC morphology

may be made during the dermal puncture procedure and require a supply of glass slides.

Very agitated children

may need to have their legs and free hand restrained

presence of hemolysis

may not be detected in samples containing bilirubin, but it interferes not only with the tests routinely affected by hemolysis but also with the frequently requested newborn bilirubin determination.

scooping motion

must be avoided as it can hemolyze the sample.

1. skin puncture devices 2. microsample collection containers 3. glass slides 4. heel warmer for use in performing dermal punctures

phlebotomy collection tray or drawing station should contain:

blue band tubes

plain tubes

thumb

possible calluses

accidental contact with the bone, followed by infection or inflammation (osteomyelitis or osteochondritis)

primary danger in dermal puncture

1. heel 2. distal segments of the third and fourth fingers

primary dermal puncture sites

Plastic collection tubes: Microtainer (Becton, Dickinson, Franklin Lakes, NJ)

provide a larger collection volume and present no danger from broken glass.

International Technidyne Corporation (Edison, NJ)

provides a range of color-coded, fully automated, single-use, retractable, disposable devices in varying depths.

The Clinical and Laboratory Standards Institute (CLSI)

recommends that the incision depth should not exceed 2.0 mm in a device used to perform heelsticks

papoose-style wrap

restraining a child in

Longer incisions

should be avoided because they will produce unnecessary damage to the heel or finger

Heparinized tubes

should be used for hematocrits collected by dermal puncture

Alternating between dermal puncture and venipuncture

should not be done when results are to be compared.

To prevent contact with bone

the depth of the puncture is critical

clay sealant or a plastic plug

the end of the capillary tube that has not been used to collect the sample is closed with