The sublingual microcirculation is impaired in sepsis and septic shock. Sidestream dark field imaging technology has been developed into a clinical tool to help the clinician assess the microcirculation at the bedside. The ideal resuscitation fluid has not been identified. The investigators aim to use this new bedside technology to establish the microcirculation properties of two popular resuscitation fluids.

Sepsis and septic shock are diseases of the microcirculation. Recent developments in microcirculation imaging have illustrated the extent of the impairment of the microcirculation in these diseases of critical care. Heterogenous flow, stagnation and microthrombi can all be seen clearly in the sublingual region using a sidestream dark field imaging device.

One of the key treatments for sepsis and septic shock is timely administration of intravenous fluids. Which fluid is administered is a matter for debate which has not been settled by several large trials. De-resuscitation has become increasingly important as physicians realise the implications and associated risks of excess fluid administration in ICU. Avoiding excess fluid administration at the resuscitation stage is therefore desirable. One of the prevailing theories about the function of albumin or colloid resuscitation is that it remains in the the intravascular space for a longer period of time, thereby continuing to benefit the patient and avoiding administration of excess fluid. However, recently albumin was tested against crystalloid for resuscitation and was shown to be effective but with no improvement in survival.

It is possible, however, that albumin is having an initial beneficial effect at a microcirculation level. Macrohaemodynamic improvements are not necessarily matched by improvements in blood flow and oxygen delivery to cells, this has been referred to as haemodynamic incoherence.

This randomised, prospective study aims to compare crystalloid and albumin resuscitation at a microcirculation level.

Inclusion Criteria:

• Sepsis; suspected source of infection, tachycardia, tachypneic, hyperlactatemia, hypotensive requiring vasopressors, febrile >38.5degrees Celsius
• Fluid responsive; pulse pressure variability >10% or passive leg raise positive

Exclusion Criteria:

• Fluid overloaded; pulmonary oedema, significant peripheral oedema
• Heart Failure, cardiogenic shock, recent MI
• Receiving regular albumin 20%