Sampling Methods Flashcards
examples of diagnostic sampling methods?
FNA
Biopsies
Joint and CSF taps
Thoracocentesis
Pericardiocentesis
Abdominocentesis
BAL
What equipment do you need for an FNA?
Gloves
Needles
Slides
Slide container
Pencil
Lab form
where do you normally perform an FNA?
Lymph nodes
Small masses
Internal organs
what can you diagnose with an FNA?
checks sites for Inflammation and neoplasia
what are the advantages of an FNA?
Diagnostics
Minimally invasive
Can be done without sedation/GA in most cases
what are the disadvantages of an FNA?
Haemorrhage - low risk
Introducing infection - low risk
Organ perforation - if internal organs
Introduction of air - lung FNA
what is the difference between fenestration and aspiration?
two types of FNA techqniues
Fenestration
- uses only a small needle
- good for small areas (eg small masses)
- less blood contamination as no neg pressure from syringe
- less cellular damage as no neg. pressure from syringe
- can’t do on organs as syringe stops air from entering the cavity
Aspiration
- provides negative pressure
- good for firm masses that havent worked with fenetration
- good for painful and sensitive areas
- only need to enter site once
what stains are used on an FNA sample?
inhouse = diff-quick
external = wright stain
what is the difference between a biopsy and an FNA?
FNA
- little to no sedation
- non-specific cytology
- results often non-diagnostic
biopsy
- easier to visualise on US
- can do laparoscopic or surgical biopsies
- a diagnosis is quarenteed
- high complications - haemorrhage
- requires sedation/GA - so fasting
- small needles can cause tissue crushing and fragmentation
what equipment do you need for a biopsy?
Sterile Gloves
Biopsy needle
Formalin pot
Slides
Slide container
Pen
Lab form
where do you normally perform a biopsy?
Internal organs
Commonly done during surgery
what can you diagnose with a biopsy?
Inflammation
Infection
Neoplasia
what are the disadvantages of a biopsy?
Painful
- requires sedation or GA
High risk of haemorrhage
- coagulation testing is vital prior to liver/spleen biopsy
Risk of pneumothorax if lung
Damage to other organs
Vagal response (cats)
Hypertensive crisis – adrenal gland
what equipment do you need for a thoracocentesis?
gloves
clippers
chloroprep
lidocaine
blade
butterfly needle
syringe
3-way-tap/one way valve
kidney dish
EDTA tube
what is the site of insertion for a thoracocentesis?
7th-9th intercostal space
avoids liver and heart
what do different samples from a thoracocentesis suggest?
blood = haemothorax
- neoplastic effusion
- run PCV
puss = pyothorax
- bacterial infection in chest cavity
- run cytology
air = pneumothorax
- lung rupture
pale liquid = chylothorax
- lymph fluid
- thoracic duct damaged
- run biochem
neoplastic
- run cytology
what are the advantages of a thoracocentesis?
Diagnosis
Therapeutic
- removes fluid or air from lungs
- improves inflation and ventilation
what are the possible complications of a thoracocentesis?
Can require sedation/GA
- depending on patient compliance
Risk of haemorrhage and pneumothorax
Must be monitored closely after procedure
what equipment do you need for a pericardiocentesis?
gloves
clippers
chloroprep
lidocaine
blade
periocardiococentesis catheter
syringe
3-way-tap/one way valve
kidney dish
EDTA tube
what is the site of insertion for a pericardiocentesis?
3rd-5th intercostal space
ideally right lateral
what can a pericardiocentesis let us diagnose?
often neoplasia
run cytology to confirm
whatchecks should you perform during a pericardiocentesis?
ensure patient is on an ECG
- hit heart = arythmias
check small sample for clotting before draining
- confirms not blood from heart
what are the possible complications of a pericardiocentesis?
Painful
Requires sedation/GA in most cases
Hgh risk of hitting major vessels/perforating ventricle
Haemorrhage
Arrythmias
Pneumothorax
Effusion is very likely
what are the advantages of a pericardiocentesis?
Diagnosis
Therapeutic
- remove fluid from cardiac space
- stop/prevent cardiac tamponade - pressure preventing filling of right ventricle
what equipment is needed for a joint tap?
sterile gloves
clippers
chloroprep
needle
syringe
slides
EDTA and serum tubes
best technique for a joint tap?
Flex joint to open joint capsule
what can a joint tap help us diagnose?
collection of synovial fluid
- smear and cytology
- EDTA for WBC count
- heparin for clot testing
- blood culture
also helps differentiate:
- inflammatory or infectious
- traumatic, acute or chronic
crude assessment of synovial fluid?
what can it tell us?
colour
- normally clear
- yellow = bleeding (bilirubin)
clarity/apacity
- normally clear
- more opaque = inflammation
viscosity
- normally quite thick
- if thinned then infection/inflammation
what are the disadvantages of a joint tap?
high risk of intoducing infection
some risk of haemmorrhage
requires sedation/GA
what equipment do you need for a cerebrospinal fluid tap?
clippers
chloroprep
sterile gloves
spinal needle
- no syringe as neg pressure causes damage
EDTA tube
where can you perform a CSF tap?
cisternal - preferred
lumbar
what can you diagnose with a CFS tap?
should be colourless, ordorless and clear
- if not then issue
cytology - check bacteria/inflammatory cells
protein assessment
fungal culture - check toxoplasma/nesopora
what are the disadvantages of CSF taps?
Possible trauma to the spinal cord
Introduction of infection
Raises intracranial pressure
- brain herniation
- avoid cisternal if patients already have raised pressure
Must be under GA
what equipment do you need for an abdominocentesis?
gloves
clippers
chloroprep
butterfly needle
slides
if drain then 3-way tap
EDTA tube
reasons for ascites?
heart failure
uroabdomen - trauma
splenic or GI rupture/trauma
- haemoabdomen
low protein = low albumin
FIP
infection
where do you perform an abdominocentesis?
centre of linea alba
use ultrasound to guide into fluid pockets
what can an abdominocentesis allow us to diagnose?
neoplasia
haemorrhage
FIP (yellow and straw-like)
cytology
- bacteria/infection
biochemistry
- hypoalbuminaemia or urine
what are the advantages of an abdominocentesis?
diagnosis
therapeutic
- reduces abdominal pressure
- improve ventilation
- reduce pressure on organs
what are the disadvantages of an abdominocentesisis?
risk of perforating internal organs
risk of haemorrhage
sedation likely needed
what equipment do you need for a broncho-alveolar lavage?
Intubation equipment
EDTA
Serum tubes
Gloves
Syringe
Saline
Endoscope
where do you perform a BAL?
down ET tube
what can a BAL allow us to diagnose?
Pneumonia
Lungworm
Asthma
what are the disadvantages of a BAL?
risk of hypoxia
- monitoring spO2 is vital
bronchospasm post proedure common
- especially in cats
may worsen respiratory signs
- due to inflammation
