Hardcore Diagrams I – RESP + CVSHardcore Diagrams I – RESP + CVS CO 2 ventilation curve Reduce threshold (RIGHT shift) – sleep, low dose opioids, light anaesthesia, alkalosis,

Hardcore Diagrams I – RESP + CVS CO2 ventilation curve

Reduce threshold (RIGHT shift) – sleep, low dose opioids, light anaesthesia, alkalosis, denervation peripheral chemoreceptors Reduce sensitivity (↓gradient) – anaesthesia, high dose opioids Increase threshold (LEFT shift) – acidosis, pain Increase sensitivity (↑gradient) – hypoxia Note: acidosis DOES NOT alter sensitivity (i.e. gradient) O2 ventilation curve

Spirometry of pregnancy

Summary:

(1) TV 40% increase (2) TLC/FRC/RV all 20% decrease (cephalad migration of diaphragm)

Ageing TLC Unchanged FRC Increase slightly RV Increase FVC Decreased

Single breath nitrogen washout technique Technique 1. Breathe room air 2. Breathe out 3. Breathe in 100% O2 to TLC 4. Breathe out – measure N2 conc 5. Plot N2 conc vs volume

Phase I – anatomical dead space Phase II – mixed alveolar + dead space Phase III – plateau phase = mixed alveolar Phase IV – terminal rise = apical low V/Q alveoli Measures (1) anatomical deadspace and (2) closing volume Pressure Volume Loop

Work of Breathing vs Respiratory Rate

Resistive work – airflow Elastic work Flow Volume Loops in Disease

V/Q Matching Curve

Airway Resistance

Max airway resistance @ 4th generation Note: the unit should be cmH2O / (L/s)

Alveolar, Intrapleural, Transpulmonary Pressures vs Time

Key features: Inspiration shorter duration than expiration Intrapleural pressure is see-saw (acceleration/deceleration) Alveolar pressure is sinusoidal

Chest Wall + Lung + Total Compliance

Plot lung volume on y-axis vs recoid pressure on x-axis Positive recoil pressure = springing inwards Negative recoil pressure = springing outwards When total recoil pressure = 0 ! balance of lung and chest wall ! this is FRC When CW+L crosses L curve is when CW crosses 0 recoil pressure i.e. when lung volume exceeds certain threshold, BOTH chest wall and lung want to spring inwards Lung and CW curve y-axis should start from residual volume and go up to total lung capacity

Wigger’s diagram

Pulmonary Artery Catheter Trace

Note1: negative intrathoracic pressure transmitted to RV ! RV diastolic pressure may be negative, esp. during inspiration Note2: blip in RV trace prior to isovolumetric contraction = atrial kick Note3: dichrotic notch for PA trace CVP waveform vs Pathology

Lost a wave ! atrial fibrillation

Prominent a-wave + attenuated y-descent ! tricuspid stenosis

Cannon a-wave ! junctional rhythm, complete heart block, retrograde conduction, etc

Fused c-v wave ! tricuspid regurgitation

Steep x and y descents ! pericardial constriction (don’t really understand why this occurs)

Prolonged y descent ! cardiac tamponade (don’t really understand this bit) Arterial Trace

Features of ageing: - decreased contractility ! ↓dP/dt - decreased compliance ! higher peak - decreased incisura - loss of Windkessel effect ! rapid descent

Features of peripheral vs aorta trace: phase delay, ↑SBP/↓DBP, loss of incisura due to damping, diastolic hump due to reflection

Coronary Blood Flow vs Time

Systole Mean aortic root pressure = 120 mmHg Mean RVP = 25 mmHg Perfusion pressure = 95 mmHg Mean LVP = 120 mmHg Perfusion pressure = 0 mmHg Diastole Mean aortic root pressure = 80 Mean RVP = 5 mmHg Perfusion pressure = 75 mmHg Mean LVP = 5 mmHg Perfusion pressure = 75 mmHg

Cardiac Action Potential