2021B05 Draw, label and describe the waveforms and pressures that are seen in each anatomical location during insertion of a pulmonary artery catheter.

List:

· Pressure trace

· Normal pressures

· Waveform components

· Factors increasing pressures

Pressure trace:

Normal pressures:

CVP	0-5cmH2O
RVP	25/0 mmHg (pressure can be subatmospheric during filling)
PAP	25/8 mmHg
PCWP	6-12 mmHg

Waveform components:

CVP = RAP	· a wave: atrial contraction · c wave: closure of TV · x descent: TV pulled downward, atrium relaxes and elongates · v wave: atrial filling during ventricular systole · y descent: open of TV, diastolic filling
RVP	· Atrial systole: small upstroke beforehand · Systolic upstroke: isovolumic contraction, rapid ejection, reduced ejection, protodiastole · Diastole: isovolumic relaxation, rapid filling, diastasis, atrial systole, protosystole
PAP	· Systole (as above) · Diastole (above) · Dicrotic notch: due to reflection and resonance
PCWP = LAP	Wedge = balloon inflated to occlude a pulmonary artery branch · a-c wave: atrial systole and closure of MV · x descent: MV pulled down, atrium relaxes and elongates · v wave: atrial filling during ventricular systole · y descent: opening of MV, rapid ventricular filling

Factors increasing pressures:

CVP	· ↑Central venous blood volume o ↑Venous tone o Skeletal muscle pump o Diaphragm pump o Right ventricular failure o TR, TS · ↓Central venous compliance o Positive pressure ventilation o Straining
RVSP	· Pulmonary hypertension · Pulmonary stenosis
mPAP	· Secondary to LV failure · Secondary to thromboembolic disease · Secondary to chronic hypoxia o V/Q mismatch: e.g. severe COPD / emphysema o Low VA: e.g OSA, OHS o Low PiO2: high altitude · Inflammatory or connective tissue disease · Idiopathic
PCWP	· ↑Venous return · ↓LV compliance · ↓LV emptying (↓LV contractility, ↑LV afterload)

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