An observational study of the state of the renal and systemic circulations in patients with early septic shock. Both macro and microvascular parameters will be assessed using echocardiography, sublingual incident dark field video-microscopy and renal contrast enhanced ultrasound. Patients will be categorised by KDIGO degree of kidney injury at Day 7 and stratified. Haemodynamic and perfusion based variables over time for these groups will be compared to assess the impact of changes in same on the development of AKI. Lab based work to quantify renal injury biomarkers will also be undertaken.

Inclusion Criteria:

Age > 18 years Within 48 hours of ICU admission Evidence of suspected or confirmed infection Serial Organ Failure Assessment (SOFA) score increase of 2 or more (assuming baseline 0 if no previous measures) Requiring vasopressor therapy to maintain a MAP > 65mmHg Lactate > 2 mmol/l despite initial fluid resuscitation

Exclusion Criteria:

Known intolerance to Sonovue or any other ultrasound contrast agent Acute Respiratory Distress Syndrome Pregnancy Breast Feeding mothers Patients not expected to survive 24 h in whom the intent of treatment is palliative

Adult patients with early septic shock admitted to ICU