chapter 9: preexamination / preanalytical considerations

basal state

resting state of body early in the morning after fasting 12 hours

basal state specimen

• ideal for establishing reference ranges on inpatients

• effects of diet, exercise, etc. on test result are minimized

basal state is influenced by

age, sex, conditions of body

this symptom in a patient may indicate liver inflammation caused by hepatitis B or C virus

jaundice

if you have no choice by to draw in an area with a tattoo, try to insert the needle in a spot that does not contain dye

true

tattoos may be more susceptible to infection; dyes may interfere

true

use another site if possible or draw below (distal to) damaged veins

true

sclerosed

hardened veins

thrombosed

clotted veins

edema

• swelling caused by abnormal accumulation of fluid in tissues

• results when fluid from IV infiltrates surrounding tissues

• contaminates blood with tissue fluid

hematoma

• swelling or mass of blood

• caused by blood leaking from vessel during venipuncture

• can be painful, contaminate blood sample, obstruct blood flow

mastectomy

• surgical breast removal

• lymph flow is obstructed with removal of lymph nodes

• swelling and infection may be present

• can change blood composition

obese patients

use longer or bariatric tourniquet and try median cubital or cephalic vein

paralysis

• avoid drawing blood from paralyzed arm

• increased chance of thrombosis

intravenous line (IV)

• catheter inserted in peripheral vein

• avoid drawing blood from arm containing IV, if possible

IV catheter lock

• needless connection device in the form of a stopcock or cap

• saline lock

• heparin lock

arterial line (a-line)

• catheter placed in an artery (usually radial)

• provide accurate and continuous measurement of blood pressure

• no tourniquet or venipuncture on this arm

arteriovenous (AV) shunt/fistual/graph

• permanent surgical fusion of an artery and a vein

• created for dialysis access

only nurses and other specially trained personnel are allowed to draw blood specimens from vascular access devices (VADs)

true

a phlebotomist typically assists by supplying the appropriate tubes, and if a syringe is used, safely transferring the blood to the tubes

true

can mix arterial and venous blood if drawn from fistula

true

blood sampling device

• connected to arterial or central venous catheter to collect blood

• reduces chance of infection

• prevents needlesticks

central vascular access devices (CVADs)

• known as indwelling lines

• consist of tubing inserted into a main vein or artery

• used for

  • administering fluids and medications

  • monitoring pressures

  • draw blood

types of CVADs

• central venous catheter (CVC) or line

• implanted port

• peripherally inserted central catheter (PICC)

central venous catheter (CVC) or line

• inserted into large vein (subclavian)

• advanced into superior vena cava

implanted port

• small chamber attached to indwelling line

• surgically implanted under skin (upper chest / arm)

• self-sealing chamber located by palpating the skin and accessing with a special needle

peripherally inserted central catheter (PICC)

inserted in veins of extremities (AC vein) and threaded into a main vein leading to the heart

adhesive allergy

place gauze square over site, have a patient remove in 15 minutes, or have patient apply pressure for 5 minutes instead of bandage

antiseptic allergy

• if allergic to iodine, then use alcohol

• if allergic to iodine and alcohol, then use chlorhexidine

excessive bleeding

• patients on aspirin or anticoagulant may bleed longer

• maintain pressure until bleeding stops

• if bleeding continues > 5 minutes, notify appropriate personnel

never apply a pressure bandage instead of maintaining pressure until bleeding has stopped, and do not miss an outpatient or leave an inpatient until bleeding has stopped or the appropriate personnel have taken charge of the situation

true

syncope

• loss of consciousness and postural tone

• caused by insufficient blood flow to brain

• lower patient’s head and apply cold compress to back of neck

petechiae

tiny, nonraised red spots, appear on arm when tourniquet is applied

seizures/convulsions

• discontinue draw immediately

• hold pressure over site without restricting patient’s movement

hematoma formation

• discontinue draw immediately and hold pressure over site for 2 mins

• offer cold compress or ice pack if it is large and swollen

iatrogenic anemia

anemia brought about by blood loss from blood draws

claw hand

refers to abnormal hand position caused by ulnar nerve injury

reflux of additive

• blood flows back into vein from collection tube

• tube additive may cause adverse reaction

hemoconcentration

• a decrease in fluid content of blood

• an increase in non-filtrable large molecules

• caused by stagnation of normal venous flow due to tourniquet

hemolysis

damage to or destruction of red blood cells

needle bevel partially into vein causes blood leakage into tissue (hematoma)

true

needle bevel penetrating a valve prevents blood flow. needle may vibrate

true