Physiology of shock and volume resuscitation

In shock, hypoperfusion of vital organs can lead to their failure. Recognizing shock, identifying the type and treating it promptly saves lives. Monitoring of haemodynamic and cellular end points is crucial in guiding treatment and improving outcomes. This article therefore focuses on the pathophysiology of shock, volume resuscitation, haemostasis and approaches to management. The body has a number of intrinsic homeostatic mechanisms for controlling blood pressure and organ perfusion which are pushed to their limits and beyond in disease. Replacement of circulating volume with fluids or blood is often necessary, but the best strategy depends on the clinical situation and latest evidence. Coagulopathy can accompany haemorrhage, particularly in trauma, and correction should be guided by testing. In haemorrhage, the aim is to stabilize the patient until definitive control can be achieved by intervention. Drug therapy to increase blood pressure and cardiac output may be necessary to increase the time available to treat underlying pathologies.