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The normal post-operative cardiac surgical patient is not critically ill.  The UNWELL post-operative cardiac surgical patient is TRULY critically ill.  The sicker the patient is pre-operatively the sicker they will be post-operatively and the longer they will take to get well.  Most patients get better of their own accord

Cardiovascular:

1. Contractility
   • Contractility improves initially after CP
   • Maximum contractility post-op without intervention is at 4 hours post CP
2. Peripheral circulation
   • Rewarming causes vasodilation
   • changes in catecholamine, ANP, renin-angiotensin systems cause variable changes in the peripheral vasculature
   • This is further exacerbated by pre-op state e.g. hypertension, ect and pre-op medicatins
3. Peripheral perfusion
   • Warming
   • Good tissue refill
4. Heart rate
   • Increases with vasodilation and reduction in filling pressures
   • Stays constant as patient filled in response to vasodilation
5. Blood pressure
   • Decreases with vasodilation and reduction in filling pressures
   • Stays constant as patient filled in response to vasodilation
6. Filling pressures (CVP/PCWP)
   • Decreases with vasodilation and increasing contractility (in the early phase)
   • Stays constant as patient filled in response to vasodilation

Respiratory:

1. Gas exchange
   • Combination of microemboli and activated blood enzymes leads to decreased functional residual capacity, pulmonary shunting and an increased alveolar-arterial oxygen gradient, V/Q mismatch, microateletasis, endothelial cell swelling and increased lung fluid
2. Intubated
   • Higher PEEP and FiO2 may be necessart early on to combat the physiological changes associated with CPB
   • Normalisatin of measured pulmonary parameterrs and other indices of patient wellbeing will allow for extubation
3. Extubated
   • Supplemental inspired oxygen, adequate analgesia and physiotherapy will allow for rapid return (1-2 days) of the normal pre-operative state

Renal:

• Variable responses of renal microvasculature, glomeruli dependent on many pre-operative and peri-operative factors
• Considerable renal reserve in most patients
• Urine output in the early postoperative course is usually excessive as the kidneys excrete the extra volume required during CPB
• There is often little or no change in serum urea, creatinine, in the post-operative period

Gastrointestinal system:

• Splanchnic blood flow is usually well maintained after CPB
• Hepatic and pancreatic function normally well maintained after CPB
• GI absorption of a number of subtrates (eg complex sugars) changes post CPB
• Normally no major derangement in GI function post operatively

Central nervous system:

• Post-operative neurological dysfunction occurs with considerable frequency
• Pre- and peri- operative factors are very important in causation
• The most important physiological cause - micro-emboli
• Normally complete return of all central and peripheral neurological function
• Major CVAs in 1=2% of post-op patients
• Neuro-psychometric changes very common post CPB
• Depression (mild) in up to 30% of patients
• Intellectual deficit (mild) in up to 50% of patients in early post-operative course, rapidly diminishes

Bleeding:

• Cardiac surgery causes a post-operative bleeding tendancy
• The primary cause appears to be fibrinolysis caused by blood contact with the biomaterial components of heart-lung machine
• Platelet dysfunction common which further exacerbates fibrinolytic tendancy
• Bleeding must be seen in the context of the patients pre- and peri- operative states and the surgeon