3 DERMAL PUNCTURE

• Although venipuncture is the most frequentlyperformed phlebotomy procedure, it is notappropriate in all circumstances.
• POCT (Point-of-Care-Testing) make it possible toperform a majority of laboratory tests on microsamples of blood obtained by dermal puncture onboth pediatric and adult patients
• Dermal/Capillary/Skin puncture belongs to a sampling technique called microcollection technique (trying to collect 1 mL (at most) of blood from a patient)
• Dermal Puncture is the ideal blood collection technique for children 2 years old and below:

  1. Large superficial veins are often reserved for intravenous therapy (para ‘ yung mga veins ay maswero; for antibiotics.
  2. Deep veins may cause complications and injury caused by restraining the child 3. Drawing excessive amounts of blood from premature and small infants can rapidly cause Anemia (150 mL of blood) 4. Certain tests require capillary blood, such as newborn screening tests and capillary blood gases
• Dermal Puncture in Adult Patients

  1. Burned or scarred patients receiving chemotherapy 3. Patients with thrombotic tendencies 4. Geriatric or other patients with very fragile veins 5. Patients with inaccessible veins (amputee,injury, etc)

  6. Obese patients 7. Apprehensive patients 8. Patients requiring home glucose monitoring and point-of- care test
• IMPORTANCE OF CORRECT COLLECTION

  • Smaller amount of blood that is collected and thehigher possibility of sample contamination,microclots, and hemolysis (occurs when red bloodcell is ruptured from one reason to another)
  • Hemolysis may occur in dermal puncture for thefollowing reasons:

  1. Excessive squeezing of the puncture site(“milking”)2. Newborns have increased numbers of red bloodcells (RBCs) and increased RBC fragility3. Residual alcohol at the site4. Vigorous micing of the micro collection tubesafter collection
• COMPOSITION OF CAPILLARY BLOOD

  • A mixture of arterial and venous blood and maycontain small amounts interstitial and intracellularfluids• Warming the site before sample collectionincreases blood flow as much as sevenfold, therebyproducing a sample that is very close to thecomposition of arterial blood
• DERMAL PUNCTURE DEVICES

  1. Capillary Tubes
  2. Microcollection Tubes
  3. Alcohol Pads
  4. Gauze
  5. Sharp Containers
• SITE COLLECTION

  • Primary danger in dermal puncture is accidentalcontact with the bone, followed by infection orinflammation (osteomyelitis or osteochondritis).
• SITE COLLECTION

  • Can be avoided by selection of puncture sites thatprovide sufficient distance between the skin andthe bone
• SITE COLLECTION

  • The primary dermal puncture sites are the heel andthe distal segments of the third and fourth fingers(based on the age and size of the patient)
• SITE COLLECTION• Performing dermal punctures on earlobes is not recommended (less chance of collecting blood). Thechoice of a puncture area is based on the age and size of the patient.
• The 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.
• The heel is held between the thumb and indexfinger of the non-dominant and, with the indexfinger held over the heel and the thumb below theheel.
• Finger punctures are performed on adults andchildren over 1 year of age.
• Fingers of infants younger than 1 year may notcontain enough tissue to prevent contact with thebone.
• The fleshy areas located near the center of the thirdand fourth fingers on the palmar side of the nondominantand are the sites of choice for fingerpuncture
• The finger is held between the non-dominantthumb and index finger, with the palmar surfacefacing up and the finger pointing downward toincrease blood flow
• The heel bone is called Calcaneus
• PHLEBOTOMIST PREPARTION

  • Requisition from• Wearing of gowns and gloves• Extensive hand washing• Carrying only the necessary equipment to thepatient area
• • Requisition form, verbal identification (let thepatient state his/her name; no abbreviations), andID band (in case, the patient is confined and asleep)• Verbal identification of pediatric outpatients mayhave to be obtained from the parents (minor of outsound mind)
• PATIENT POSITION

  • • Must be seated or lying down with the handsupported on a firm surface, palm up, and fingerspointed downward for fingerstick For heelsticks, infants should be lying on the backwith the heel in a downward positionPatient should not change their positionanymore (in position for 10 mins)
• SITE SELECTION

  • Heel
  • Distal segments of the third and fourth fingers
• • Areas selected for dermal puncture should not becallused, scarred, bruised, edematous (swollen;nagmamanas), cold or cyanotic, or infected.• Do not collect blood from the fingers on the side ofa mastectomy without a health-care provider’ sorder.
• HEEL PUNCTURE SITES

  • Infants younger than 1 year
  • Punctures should not be performed in otherareas of the foot, and particularly not in thearch
• FINGER PUNCTURE SITES

  • Adults and children over 1 year of age
  • Fleshy areas located near the center of the thirdand fourth fingers on the palmar side of thenondominant hand
  • Problems associated with the use of the otherfingers include possible calluses on the thumb,increased nerve endings in the index finger, anddecreased tissue in the fifth finge
• WARMING THE SITES

  • Warming dilates the blood vessels and increasesarterial blood flow
  • Towel moistened with warm water (42 degreesCelsius) or activating a commercial heel warmer and covering the site for 3 to 5 minutes effectivelywarms the site
  • The site should not be warmed for longer than 10minutes or test results may be altered
• CLEANSING THE SITE

  • Site is cleansed with 70% isopropyl alcohol, using acircular motion
  • The alcohol should be allowed to dry on the skin formaximum antiseptic action, and the residue may beremoved with gauze to prevent interference withcertain tests
• • Failure to allow the alcohol to dry:Causes a stinging sensation for the patientContaminates the sampleHemolyzes RBCs (hemolyze specimen = repeatextraction)Prevents formation of a rounded blood drop(lalabnaw) because blood will mix with thealcohol and run down the finger
• PERFORMING THE PUNCTURE

  • Heel or finger should be weel supported and held firmly, without squeezing the puncture area
  • Massaging the area before the puncture may increase blood flow to the area
• PUNCTURE DEVICE POSITION

  • Corresponds to the size of the patient • Remove the trigger lock if necessary • Firmly place device on selected site • Don’ t indent skin when placing the lancet on the puncture site • Should be aligned to cut across (perpendicular to) the grooves of the fingerprint or heel print • Depress the lancet release mechanism and hold for a moment, then release • Pressure must be maintained because the elasticity of the skin naturally inhibits penetration of the blade
• SAMPLE COLLECTION

  • First drop of blood must be wiped away with a clean gauze • Firm pressure should produce free flowing blood; shouldn’t be obtained by “milking” • Alternately applying pressure to the area and releasing it produces blood flow • Tightly squeezing the area with no relaxation cuts off blood flow to the puncture site
• CAPILLARY TUBES AND MICROPIPETTES

  • Hold micropipettes horizontally to prevent air bubbles • Place the end of the tube into the drop of blood and maintain the tube in a horizontal position • Removing the microhematocrit tube from the drop of blood causes air bubbles in the sample - The capillary tube’ s tip should only be touching the blood, not the skin
• • When the tubes are filled, they are sealed with sealant clay or designated plastic caps • When using a sealant tray, place the end that has not been contaminated with blood into the clay taking care to not break the tube - Prevent the blood from leaking out during the procedure
• MICROCOLLECTION TUBES

  • 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 • The tip of the collection container is placed beneath the puncture site and touches the underside of the drop • Gently tapping the bottom of the tube may be necessary to force blood to the bottom
• ORDER OF COLLECTION

  • Capillary blood gases • Blood smear (Glass slides) • EDTA tubes (Lavender) • Other anticoagulant tubes • Serum tubes (Red/Yellow)
• BANDAGING THE PATIENT

  • When sufficient blood has been collected, pressure is applied to the puncture site with gauze • The finger or heel is elevated and pressure is applied until the bleeding stops • Confirm that the bleeding has stopped before removing the pressure
• LABELING THE SAMPLE

  • Microsamples must be labelled with the same information required for venipuncture samples - Manually write the name, full name, age and sex, date and time of collection, initials of the phlebotomist
• COMPLETION OF THE PROCEDURE

  • Disposing of all used materials in appropriate containers • Removing gloves • Washing hands • Thanking the patient and/or parents for their cooperation - Monitor the patient for nausea or fainting • As with venipuncture, it is recommended that only two punctures be attempted to collect blood