Phlebotomy Ch.10: Lecture 1

Dermal Puncture

is an alternative procedure when small amounts of blood are needed or a venipuncture is not advised or possible

it is a usual procedure for infants and children under 2 yrs old

also for a bleeding time, ancillary blood glucose, and obese patients testing

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

also for pts with only one test ordered, those receiving IV therapy, frequent blood tests, and those who are at risk for injury from restrains that might be needed for venipuncture

procedure can't be used for blood cultures, sed rates, and coagulation tests

not done for dehydrated pts, shock, on sites that are swollen, circulation is compromised

Venous v. Capillary

capillary blood is a mix of arterial blood, venous blood, and tissue fluid

hemoglobin and glucose values are higher in capillary blood

K, Ca, and total protein values are higher in venous blood

Puncture devices

microsample containers

come in microcollection tubes, capillary tubes, and micropipets

the puncture devices come in different types and sizes to meet different needs

meet safety regulations

devices contain retractable blades that lock to prevent being used again

warm devices will increase capillary circulation and blood flow

wash cloths/commercial heel warmers can be used to

the temperature should not exceed 42 degrees Celsius and applied for 3-5 minutes

Width and depth

depth should not exceed 2.0 mm in infant heels and 0.65 to 0.85 mm in premature infants

care should be taken not to puncture the heel bone

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

puncture should be done on the palmer surface of the distal segments of middle or ring finger of non dominant hand

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

Dermal on infants

under one years old and not walking

use medial or lateral portion on the plantar (bottom) surface of heel

follow standard precautions making sure to wash hands and put on gloves

always greet patient and parents, if present, obtain consent, identify pt's as would

on pt's infants the armband may be on ankle

Procedure

  1. Document on the requisition that you are performing a dermal puncture
  1. Assemble Equipment

use pt age, size, tests ordered to determine puncture device needed

  1. Select and clean the site warming first, then cleaning with 70% isopropyl alcohol
  1. hold the finger firmly to prevent moving during the puncture
  1. Make puncture

count to two before lifting blade to make sure blade has made a complete puncture and retracted

dispose of lancet in sharps container

  1. prepare to collect sample

wipe away first drop with clean gauze to prevent tissue fluid contamination of specimen

keep finger in downward motion applying a "squeeze and release" pressure to the finger

  1. Collect sample

Touch the scoop of the tube to the drop, allowing it to run into the tube; make sure to mix the # of times required by manufacturer

hold the capillary tube horizontally without touching the skin so to prevent tissue fluid contamination

order of collection

slides first to minimize effects of platelet clumping

  1. Complete procedure

lavender tubes for CBC's

other tubes with anticoagulants serum tubes last

apply bandage after bleeding has stopped

do not bandage children under 2 years since they could remove it and choke on teh bandage

Make sure equipment has been equipment has been picked up and bed rails are up

label specimen, remove gloves, and wash hands

thank pt