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Intensive care scenarios

Clinical findings

Scenario	Considerations	Managment strategy
CABG On pump	Patients with pre-existing good LV are usually hypertensive and tachycardic Produce a large initial diuresis	Hypertension best managed with an infusion of GTN 1-20mg/hr (reduces coronary vasospasm, increases CBF, decreases SVR) Significant proportion develop hypotension due to long t1/2 of ACE-inhibitors Noradrenaline 0.03-0.05mcg/kg/min sufficient for BP control Dopamine 3-8mcg/kg/min is renal impairment Levosimendan: calcium ion sensitizer which binds calcium to cardiac troponin C - does not increase cAMP / intracellular calcium therefore does not increase oxygen demand Check for ST changes on ECG Failure to respond to inotropes mandates accurate assessment of cardiac indices (with Swan) +/- IABP
CABG Off pump	Patients with pre-existing good LV are usually hypertensive and tachycardic Do not produce a diuresis (usually underfilled) Significant metabolic acidosis develops in first 6 hours	Ensure adequately filled Warm (blankets, infusion) Early aspirin + LMWHeparin to ensure graft patency
Aortic stenosis	Stiff hypertrophied ventricle dependent on synchronised atrial contraction to provide 30% stroke volume Shortened filling times reduce cardiac output AF/Tachyarrythmias cause patients to decompensate rapidly	Ensure adequate preload CVP 14-16 Aim systolic pressures 80-90mmHg to preserve suture lines, reduce risk of haemorrage, stroke Anticoagulate mechanical valves Low threshold for DC cardioversion if antiarrythmic drugs do not cardiovert quickly Sequential pacing better than ventricular pacing (epicardial wires should be placed)
Aortic regurgitation	Have dilated compliant ventricles Rely on atrio-ventricular conduction	Require large volumes to raise filling pressures Removal of regurgitation means that LV performance improves compared to RV performance (filling pressures are lower) Anticoagulate mechanical valves
Aortic dissection	Involves suture of graft material to friable tissues Distal dissection channel is not obliterated by surgery; therefore extension can occur Surgery involves a period of deep circulatory arrest	Avoid hypertension: systolic <120mmHg using labetalol Correct coagulopathy (high bleeding risk due to friable tissues) Investigate descending aorta to assess distal end-organ supply especially the kidneys - percutaneous fenestration of the dissection flap may salvage organs
Mitral stenosis	Have small LV with preserved function	Reduce pulmonary hypertension and RV dysfunction Avoid high positive pressure ventilation Treat bronchospasm Treat pulmonary oedema Avoid vasoconstrictrs (eg. norad) Higher filling pressures are required to ensure CO Right sided filling pressure may not correlate with Left sided pressure because of RV dysfunction Respiratory dysfunction is common as a result of pulmonary hypertension Maintain on diuretic therapy Inotropes that offload the pulmonary vasculature should be selected: milrinone and dopamine GTN: results in pulmonary vasodilation Inhaled nitric oxide may be indicated Anticoagulate mechanical valves
Mitral regurgitation	In chronic AF variable degree of pulmonary hypertension May be associated with RV dysfunction Corrected MR may unmask LV dysfunction (when low resistance pathway is removed) Surgical repair: converts low pressure high volume system to a high pressure low volume system

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