The role of the microcirculation in the pathophysiology of meningococcal disease
microcirculatory malfunction is the cause of organ failure
- Start Date:
01 January 2006
Alderhey Children's Hospital, Liverpool, UK, Institute of Child Health, London, UK, Liverpool University, Liverpool, UK
Meningococcal disease (MCD) may present with severe sepsis, which impairs the circulation. Currently macro-circulatory variables (pulse, blood pressure, central venous pressure) are used to quantitate shock and response to treatment.
However these variables may not reflect alterations in the microcirculation (e.g. capillary blood flow). Patients with normal arterial pressure post-resuscitation may still have hypoperfused vital organs.
This hypoperfusion perpetuates hypoxia and acidosis, creating a sub-optimal environment for physiological recovery, despite apparent adequate systemic haemodynamic stabilisation. Improved microcirculation in the first 24 hours of resuscitation has been shown to predict outcome in adult patients better than changes in cardiac index, blood pressure and blood lactate. There have been no studies in children.
The microcirculation can now be investigated at the bedside using orthogonal polarisation spectral (OPS) imaging (MicroscanTM) enabling minimally invasive quantitative assessment of capillary beds. Correlation of microcirculatory variables with conventional cardiovascular variables, (including echocardiography) and laboratory parameters (production and expression of cytokines and vasoactive endothelial mediators), will help to produce a more complete picture of the cardiovascular pathophysiology in children with MCD.
The method is dynamic and repeated measurements of microcirculation before, during and after interventions in critical illness could have a major impact on outcomes related to multiple organ failure and death. OPS imaging may prove a useful tool to evaluate the effects of volume infusion and vasoactive therapy and offers the possibility of assessing the impact of therapeutic strategies directly on the microcirculation, and hence of being able to target the microcirculation as a resuscitation endpoint.