Table 2.

Physiological changes in pregnancy and in sepsis

System	Pregnancy physiological changes	Sepsis-induced changes	Combined effect
Cardiovascular	Low systemic vascular resistance with vasodilation.	Vasodilation and reduced systemic vascular resistance.	Rapid haemodynamic collapse.
	Increase in blood volume by 40%.	Tachycardia.
	Increased heart rate.	Myocardial depression.
	Increased cardiac output.	Hypotension.
	Fall in blood pressure.
	Aorto-caval compression
Respiratory	Low pulmonary vascular resistance and plasma colloid osmotic pressure.	Enhanced pulmonary microvascular pressure and permeability.	Increased susceptibility to pulmonary oedema.
	Increased tidal volume, decreased residual volume and functional residual capacity.Increased minute ventilation with compensated respiratory alkalosis.	Sepsis-induced acute lung injury.	Rapid decline in oxygenation.Adult respiratory distress syndrome.Decreased ability to compensate for metabolic acidosis.
Coagulation	Elevated factors I, II, VII, VIII, IX and XII.Plasminogen activator inhibitors I and II increase 5-fold.Reduced protein S.Antithrombin and protein C not significantly affected.	Procoagulant effects. Increased thrombin production and reduced activated protein C associated with platelet aggregation.Decreased fibrinolysis via increase in plasminogen activator inhibitor 1	Increased microvascular fibrin thrombi.Tissue hypoperfusion and end organ dysfunction.
Renal	Renal plasma flow and glomerular filtration rate increase.The renal collecting system dilates.Predisposition to urinary tract infection.	Ischaemia– reperfusion injury.Vasoconstriction.Angiotensin activity and cytokine-mediated renal cell injury.	Acute tubular necrosis.Renal failure.