Chapter 10 Dermal Puncture. Copyright © 2008 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2 Learning Objectives List situations in

Chapter 10Chapter 10

Dermal PunctureDermal Puncture

Copyright © 2008 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2

Learning ObjectivesLearning Objectives

List situations in which a dermal puncture List situations in which a dermal puncture might be preferred.might be preferred.

Explain why it is necessary to inform the Explain why it is necessary to inform the physician when capillary blood is collected.physician when capillary blood is collected.

Describe skin puncture devices, including Describe skin puncture devices, including safety features they may have.safety features they may have.

Discuss containers that may be used to Discuss containers that may be used to collect capillary blood.collect capillary blood.



List the steps in the BD Unopette dilution List the steps in the BD Unopette dilution method.method.

Explain how circulation may be increased at Explain how circulation may be increased at the puncture site.the puncture site.

Discuss proper dermal puncture site Discuss proper dermal puncture site selection.selection.

Explain why it is important to control the Explain why it is important to control the depth of the puncture.depth of the puncture.



List in order the steps for dermal puncture.List in order the steps for dermal puncture. Describe how the cut should be made when a Describe how the cut should be made when a

finger is used.finger is used. Explain why the first drop of blood is Explain why the first drop of blood is

discarded.discarded. List precautions to be observed when List precautions to be observed when

collecting capillary blood.collecting capillary blood. State the order of draw in collecting capillary State the order of draw in collecting capillary

blood.blood.



Explain the use of the bleeding time test.Explain the use of the bleeding time test. List the equipment required to perform a List the equipment required to perform a

bleeding time test.bleeding time test. List in order the steps for performing a List in order the steps for performing a

bleeding time test.bleeding time test. Explain the procedure for performing a Explain the procedure for performing a

bedside glucose test.bedside glucose test.



Dermal puncture is an alternative collection Dermal puncture is an alternative collection procedure when small amounts of blood are procedure when small amounts of blood are needed, or when venipuncture is inadvisable needed, or when venipuncture is inadvisable or impossible.or impossible.

It is the usual collection procedure for infants It is the usual collection procedure for infants and children under 2 yrs. of age.and children under 2 yrs. of age.

It is also used for bleeding times, ancillary It is also used for bleeding times, ancillary blood glucose testing, and obese patients.blood glucose testing, and obese patients.



It is used for geriatric patients, those at risk It is used for geriatric patients, those at risk for venous thrombosis, and those with burns for venous thrombosis, and those with burns or scars over venipuncture sites.or scars over venipuncture sites.

It is also used for patients with only one test It is also used for patients with only one test ordered, those receiving IV therapy, frequent ordered, those receiving IV therapy, frequent blood tests, and those who might be at risk blood tests, and those who might be at risk for injury from restraints that might be needed for injury from restraints that might be needed for a venipuncture.for a venipuncture.



Dermal punctures cannot be done for blood Dermal punctures cannot be done for blood cultures, sed rates and coagulation tests.cultures, sed rates and coagulation tests.

It should not be done on dehydration patients It should not be done on dehydration patients or those in shock, or on sites that are swollen or those in shock, or on sites that are swollen or where circulation is compromised such as or where circulation is compromised such as in a mastectomy.in a mastectomy.


Venous vs. Capillary BloodVenous vs. Capillary Blood

Capillary blood is a mixture of arterial blood, Capillary blood is a mixture of arterial blood, venous blood, and tissue fluid. It is more venous blood, and tissue fluid. It is more arterial when warmed.arterial when warmed.

Hemoglobin and glucose values are higher in Hemoglobin and glucose values are higher in capillary blood.capillary blood.

Potassium, calcium, and total protein values Potassium, calcium, and total protein values are higher in venous blood.are higher in venous blood.


Skin Puncture DevicesSkin Puncture Devices

Skin puncture devices Skin puncture devices come in different types come in different types and sizes to meet different and sizes to meet different needs.needs.

To meet safety To meet safety regulations, devices now regulations, devices now have retractable blades have retractable blades that lock to prevent being that lock to prevent being used a second time.used a second time.

Courtesy of Zack Bent. From Garrels M, Oatis CS: Laboratory Testing for Ambulatory Settings: A Guide for Health Care Professionals. Philadelphia, Saunders, 2006.


Microsample ContainersMicrosample Containers

Containers come in Containers come in microcollection tubes, microcollection tubes, capillary tubes, and capillary tubes, and micropipets.micropipets.




Warming devices will increase capillary Warming devices will increase capillary circulation and blood flow.circulation and blood flow.

Wash cloths or commercial heel warmers can Wash cloths or commercial heel warmers can be used.be used.

Temperature should not exceed 42Temperature should not exceed 42oo C and C and should be applied for 3 to 5 minutes.should be applied for 3 to 5 minutes.


Dermal Puncture Width and DepthDermal Puncture Width and Depth

Depth should not exceed 2.0 mm in infant Depth should not exceed 2.0 mm in infant heels; 0.65 to 0.85 mm in premature infants.heels; 0.65 to 0.85 mm in premature infants.

Care should be taken to not puncture the Care should be taken to not puncture the calcaneus (heel) bone.calcaneus (heel) bone.

A wider puncture cut will increase blood flow, A wider puncture cut will increase blood flow, but puncture width should not exceed 2.4 but puncture width should not exceed 2.4 mm. mm.


Dermal Puncture Sites in Adults & Dermal Puncture Sites in Adults & Older ChildrenOlder Children

Punctures should be done Punctures should be done on the palmar surface of the on the palmar surface of the distal segments of the distal segments of the middle or ring finger of the middle or ring finger of the nondominant hand.nondominant hand.

Punctures with blades Punctures with blades should be made should be made perpendicular to the ridges perpendicular to the ridges in the fingers to keep the in the fingers to keep the blood from flowing into the blood from flowing into the grooves.grooves.


Dermal Puncture in InfantsDermal Puncture in Infants

For infants under one year For infants under one year old and not walking, use the old and not walking, use the medial or lateral portion on medial or lateral portion on the plantar (bottom) surface the plantar (bottom) surface of the heel.of the heel.


Dermal Puncture ProcedureDermal Puncture Procedure

Follow standard precautions making sure to Follow standard precautions making sure to wash hands and put on gloves.wash hands and put on gloves.

Always greet patient and parents, if present, Always greet patient and parents, if present, obtain consent, and identify patient as you obtain consent, and identify patient as you would for a venipuncture.would for a venipuncture.

On inpatient infants, the armband may be on On inpatient infants, the armband may be on the ankle.the ankle.



1.1. Document on the requisition that you are Document on the requisition that you are performing a dermal puncture.performing a dermal puncture.

2.2. Assemble your equipment.Assemble your equipment.

Use the patient age, size and tests Use the patient age, size and tests ordered to determine puncture device ordered to determine puncture device needed.needed.

3.3. Select and clean the site, warming first, Select and clean the site, warming first, then cleaning with 70% isopropyl alcohol.then cleaning with 70% isopropyl alcohol.






4. Hold the finger firmly to 4. Hold the finger firmly to prevent moving during prevent moving during the puncture.the puncture.

5. Make the puncture. 5. Make the puncture. Count to two before Count to two before lifting the blade to make lifting the blade to make sure that the blade has sure that the blade has made a complete made a complete puncture and retracted. puncture and retracted. Dispose of lancet in Dispose of lancet in sharps container.sharps container.




6. Prepare to collect the sample.6. Prepare to collect the sample.

- - Wipe away the first drop with a clean Wipe away the first drop with a clean gauze to prevent tissue fluid gauze to prevent tissue fluid

contamination of the specimen.contamination of the specimen.

- - Keep the finger in a downward motion Keep the finger in a downward motion applying a “squeeze and release” applying a “squeeze and release”

pressure to the finger.pressure to the finger.



7. Collect the sample.7. Collect the sample. - - Touch the scoop of the tube to the drop, Touch the scoop of the tube to the drop,

allowing it to run into the tube. Make allowing it to run into the tube. Make sure sure to mix the number of times required to mix the number of times required by by the manufacturer.the manufacturer.

- - Hold capillary tubes horizontally without Hold capillary tubes horizontally without touching the skin so as to prevent touching the skin so as to prevent

tissue tissue fluid contamination.fluid contamination.






- Order of collect for dermal puncture:- Order of collect for dermal puncture:

* Slides first to minimize the effects of * Slides first to minimize the effects of

platelet clumping.platelet clumping.

* Lavender tubes for CBCs.* Lavender tubes for CBCs.

* Other tubes with anticoagulants.* Other tubes with anticoagulants.

* Serum tubes last.* Serum tubes last.



8. Complete the procedure.8. Complete the procedure.

- Apply a bandage after bleeding has - Apply a bandage after bleeding has stopped. Do not bandage children under stopped. Do not bandage children under 2 years of age since they could remove 2 years of age since they could remove

and choke on the bandage.and choke on the bandage.

- Make sure that equipment has been - Make sure that equipment has been picked up and bed rails are up.picked up and bed rails are up.

- Label specimen, remove gloves and wash - Label specimen, remove gloves and wash hands.hands.

- Thank the patient.- Thank the patient.


Bleeding Time Test (BT)Bleeding Time Test (BT)

A BT measures the length of time required for A BT measures the length of time required for bleeding to stop after an incision is made.bleeding to stop after an incision is made.

A BT is a screening test to assess the A BT is a screening test to assess the integrity of the vascular system and platelet integrity of the vascular system and platelet function.function.

Normal BT is 2 to 10 minutes.Normal BT is 2 to 10 minutes.


Abnormal BT ResultsAbnormal BT Results

A BT of 15 to 20 min. can mean that the A BT of 15 to 20 min. can mean that the patient has a condition that is interfering with patient has a condition that is interfering with normal platelet plug formation or the test was normal platelet plug formation or the test was performed incorrectly.performed incorrectly.

Repeat the test if only one incision was Repeat the test if only one incision was made; if two incisions were made and are made; if two incisions were made and are within minutes of each other, it is not within minutes of each other, it is not necessary to repeat the test.necessary to repeat the test.


Bleeding Time (BT) ProcedureBleeding Time (BT) Procedure

1. Assemble your equipment: 1. Assemble your equipment:

- Alcohol pads- Alcohol pads

- Blood pressure cuff- Blood pressure cuff

- BT device - BT device

- Stopwatch- Stopwatch

- Filter paper- Filter paper

- Bandages- Bandages



2. Prepare the patient.2. Prepare the patient.

- Tell the patient that scarring may occur.- Tell the patient that scarring may occur.

- Ask about any aspirin or product - Ask about any aspirin or product containing salicylates, taken within the containing salicylates, taken within the

last last 7 to 10 days, or Ibuprofen within 24 7 to 10 days, or Ibuprofen within 24 hrs. hrs. that could inhibit platelet function.that could inhibit platelet function.



3. Position the arm, select, and 3. Position the arm, select, and clean the site.clean the site.

- Select a site 5 cm. - Select a site 5 cm. below the below the antecubital antecubital crease free of veins, crease free of veins,

scars, hair, and scars, hair, and bruises.bruises.

- - Clean with alcohol Clean with alcohol and and allow to dry.allow to dry.



4. Apply the blood pressure cuff.4. Apply the blood pressure cuff.- - Inflate cuff to 40 mm Hg.Inflate cuff to 40 mm Hg.- - Maintain the pressure throughout Maintain the pressure throughout

procedure.procedure.- - Wait 30 to 60 sec. after inflation to Wait 30 to 60 sec. after inflation to

make make puncture.puncture.5. Position the device parallel to the crease of 5. Position the device parallel to the crease of

the arm and 5 cm. below.the arm and 5 cm. below.



6. Make the incision and start timing.6. Make the incision and start timing. - Use firm pressure on the skin.- Use firm pressure on the skin. - Activate device and start the stopwatch at - Activate device and start the stopwatch at

the same time.the same time. - Remove device after the blade retracts.- Remove device after the blade retracts. 7. Wick the blood every 30 seconds.7. Wick the blood every 30 seconds. - Touch only the edge of the drop until the - Touch only the edge of the drop until the

drop disappears and you can see the drop disappears and you can see the site.site.





8. Complete the test.8. Complete the test. - - Bleeding has stopped when blood is no Bleeding has stopped when blood is no

longer absorbed by the filter paper.longer absorbed by the filter paper. - - Record the time and remove cuff.Record the time and remove cuff.9. Attend to the patient.9. Attend to the patient. - - Clean the arm (do not use alcohol).Clean the arm (do not use alcohol). - - Apply a butterfly bandage and tell patient Apply a butterfly bandage and tell patient

to keep on for 24 hrs.to keep on for 24 hrs.


Ancillary Blood Glucose TestingAncillary Blood Glucose Testing

Performed at the patient’s bedside.Performed at the patient’s bedside. Used to monitor patients with diabetes Used to monitor patients with diabetes

mellitus.mellitus. Follow the procedure from the manufacturer Follow the procedure from the manufacturer

of the instrument that you are using.of the instrument that you are using. Always make sure to calibrate and run Always make sure to calibrate and run

controls prior to testing the patient.controls prior to testing the patient. Know what to do with critical values.Know what to do with critical values.

Documents

Chapter 10 Dermal Puncture. Copyright © 2008 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2 Learning Objectives List situations in