Biochemistry Tests Flashcards
sputum examination
appearance clear/colourless (chronic bronchitis) yellow-green (pulmonary infection) red (haemoptysis) black (smoke, coal dust) frothy white-pink (pulmonary oedema)
sample –> laboratory -microscopy , culture, cytology
peak expiratory flow
maximal forced expiration through peak flow meter
- estimates airway calibre
- more effort-dependent
pulse oximetry
peripheral O2 sat non invasive less than/equal to 80% = abnormal pneumonia less than 92% = serious sign -check ABG for PaCO2
pulse oximetry complication
poor perfusion motion excess light skin pigmentation nail varnish dyshaemoglobinaemias CO poisoning
arterial blood gas
herparinized blood - taken from radial/ femoral artery
pH, PaO2, PaCO2 meaured
FiO2 noted
Normal pH ABG
7.35-7.45
ph<7.35
acidosis
ph>7.45
alkalosis
normal PaO2
10.5-13.5pKa
hypoxia ccauses
ventilation/perfusion mismatch
hypoventilation
abnormal diffusion
right o left cardiac heart shunts
severe hypoxia
PaO2 <8kPa
normal PaCO2
4.5-6kPa
PaCO2 <4.5kPa
hyperventilation
PaCO2 >6.0kPa
hypoventilation
Type 1 resp failure
too little O2
PaO2<8kPa
PaCO2<6kPa
Type 2 resp failure
PaO2<8kPa
PaCO2>6kPa
little O2
too much CO2
What does spirometry measure
functional lung volumes
How are FEV1s and FVCs cmeasyred
full forced expiration in a spirometer
when does exhalation finish
until no more breaths = exhaled
is FEV1 or PEF more effort dependent
PEF
what does FEV1/FVC ratio give estimate of
airflow obstruction severity
Obstructive defect FEV1/FVC ratio
<75%
Restrictive defect FEV1/FVC
equal to > than normal
Normal FEV1/FVC ratio
75-80%
Obstructive defect examples
asthma
COPD
Restrictive defect examples
Lung fibrosis Sarcoidosis Pneumoconiosis Interstitial pneumonias Connective tissue diseases Pleural effusions Obesity Kyphoscoliosis Neuromuscular problems
what does Alveolar arterial oxygen gradient measure
difference in O2 pressure between alveolar + arterial sides
Aa gradient normal breathing range
- 2-1.5 kPa (25 yrs)
1. 5-3.0 kPa (75 yrs)
high Aa gradient hypoxia
O2 transfer problem
normal Aa gradient hypoxia
hypoventilation
lung capacities used to distinguish obstructive/ restrictive diseases
Total lung capacity
Residual volume
In obstructive airway disease what happens to TLC and RV
Increased
TLC and RV are reduced in
Restrictive lung diseases
Musculoskeletal abnormalities
explain gas transfer coefficient
CO diffusing capacity
measures
-CO uptake from single inspiration in standard time
-lung volume by helium dilution
gas transfer coefficient = high
alveolar haemorrhage
gas transfer coefficient = low
emphysema
what does the flow volume loop measure
flow at various lung volumes
radiology used in chest medicine
chest x-ray ultrasound radio-nucleotide scans computed tomography pulmonary angiography
what is ultrasound used for
diagnosis + guide drainage of pleural effusions + emphysema
radionucleotide scans are used for
ventilation/perfusion scans
-diagnose PE
bone scans
bone metastases
what is computed tomography used for
thorax diagnosing + staging lung cancer imaging hila, mediastinum, pleura high resolution CT -diagnose interstitial lung disease + bronchiectasis CT pulmonary angiography -PE diagnosis
fibreoptic bronchoscopy
local anaesthetic via nose or mouth
susoected lung carcinomas
slowly resolving pneumonia in immunosuppressed
interstitial lung disease
pre procedure investigations fibreoptic bronchoscophy
FBC CXR spirometry pulse oximetry ABGs
bronchoalveolar lavage
at time of bronchoscopy
instil + aspirate known vl warmed, buffered 0.9% saline into distal airway
bronchoalveolar lavage diagnostic indications
suspected malignancy
pneumonia immunocompromised
suspected TB
interstitial lung disease
bronchoalbeolar lavage complication
hypoxia
transient fever
transient CXR shadow
types of lung biopsy
percutaneous needle biopsy
transbronchial biopsy
open lung biopsy
percutaneous needle biopsy
under radiological guidance
peripheral lung + pleural lesions
transbronchial biopsy
@ bronchoscopy
diagnose diffuse lung disease
surgical procedures
rigid bronchoscopy
mediastinoscopy
mediastinotomy
thoracoscopy
rigid bronchoscopy
widen lumen
larger mucosal biopsies
controls bleeding
removes foreign bodies
mediastinoscopy
mediastinotomy
examination + biopsy of mediastinal lymph nodes/ lesions
thoracoscopy
examination + biopsy of
pleural lesions
drainage of pleural effusion
talcpleurodesis
