Historically, the management of haemorrhagic shock has emphasised fluid resuscitation with crystalloid solution, to achieve and maintain a normal blood pressure.21,22 However, aggressive volume resuscitation can cause serious problems, including:
- oedema, compartment syndrome23 and acute lung injury
- exacerbation of anaemia, thrombocytopenia and coagulopathy due to haemodilution24-26
- exacerbation of bleeding due to possible clot disruption.24,27
In contrast, permissive hypotension and minimal volume resuscitation are strategies in which systolic blood pressures of 80–100 mm Hg are tolerated while bleeding is controlled.28 These concepts are not new (they date back to World War I 29) and several studies have shown survival benefit.30,31 Permissive hypotension is widely practised for ruptured abdominal aortic aneurysms.32,33
Permissive hypotension is contraindicated in patients with traumatic brain injury, because reduced perfusion pressure and oxygenation can lead to secondary brain injury.34
Permissive hypotension and minimal volume resuscitation are generally preferable to aggressive volume resuscitation while active bleeding is being controlled.
Permissive hypotension is contraindicated in patients with possible traumatic brain injury.
The safe low threshold for systolic blood pressure is unknown, and elderly patients require specific consideration.
The maximum safe duration for permissive hypotension is unknown.