Respiratory physiology Flashcards
Type I alveoli
Squamous cell
Type II alveoli
Pneumocyte - surfactant produced
Where in airway is there most resistance?
Medium sized bronchi
COPD patients control of breathing
Rely on peripheral chemoreceptors, no central chemoreceptors
Central chemoreceptors
CO2
CSF
Peripheral chemoreceptors
O2
Carotid body - glossopharyngeal nerve
Aortic arch - vagus nerve
Transport of oxygen
98% bound to haemoglobin
2% dissolved in plasma
Transport of CO2
70% bicarbonate
20% bound to haemoglobin
10% dissolved in plasma
Oxygen dissociation curve shifted to LEFT by:
Increased ph
Decreased 2,3-BPG
Decreased temp
think Lungs = Left shift
Oxygen dissociation curve shifted to RIGHT by:
Decreased pH (increased acidosis)
Increased 2,3-BPG
Increased temperature
Investigations for pregnant lady ?perfortion
Erect CXR
USS
ECG changes in PE
S1Q3T3
Sinus tachycardia
Investigations for PE in pregnancy
No d-dimer
V/Q scan if normal CXR
CTPA if abnormal CXR (wedge infarct)
Why does saddle embolus kill?
Empty L atrium
Position for avoiding venous air embolism
L lateral decubitus
Cause of basal atelectasis
100% oxygen (absorbable) displaces nitrogen (non absorbable) causing alveolar collapse
ARDS
Acute (< 7 days)
Not due to cardiac failure/fluid overload
Hypoxia
CXR - bilateral opacities not due to effusion/consolidation/nodules
Exudate
High protein
Malignancy/infection
Transudate
Low protein
HF/cirrhosis
Most important lung value predicting mortality
FEV1
Obstructive lung disease
FEV1/FVC <0.8
COPD
Bronchiectasis
Asthma
Restrictive lung disease
FEV1/FVC > 0.8
Pulmonary fibrosis
ARDS
Obesity
