Lund Concept for Traumatic Brain injury

OVERVIEW

A ‘volume-targeted’ approach to the management of TBI developed by a Swedish group (not ABBA), based on physiological volume regulation of the intracranial compartments.

The Lund concept contradicts the prevailing strategem of titrating CPP to match ICP in TBI

THEORY

Normal healthy brain

• The balance between effective transcapillary hydrostatic and osmotic pressures constitutes the driving force for transcapillary fluid exchange
• The low permeability for sodium and chloride combined with the high crystalloid osmotic pressure (approximately 5700 mmHg) on both sides of the blood-brain barrier (BBB) counteracts fluid exchange across the intact BBB
• variations in systemic BP  generally are not transmitted to these capillaries because cerebral intracapillary hydrostatic pressure (and blood flow) is tightly autoregulated

In TBI

• the BBB may be partially disrupted
• transcapillary water exchange is determined by the differences in hydrostatic and colloid osmotic pressure between the intra- and extracapillary compartments
• pressure autoregulation of cerebral blood flow is likely to be impaired in these conditions
• a high cerebral perfusion pressure increases intracapillary hydrostatic pressure and leads to increased intracerebral water content and an increase in ICP

MANAGEMNT ACCORDING TO THE LUND CONCEPT

Principles

• The prevention of brain oedema formation to reduce fluid shift from capillaries into brain parenchyma, by preserving capillary colloid osmotic pressure and reducing capillary hydrostatic pressure
• The improvement of the cerebral microcirculation by the avoidance of arterial vasoconstrictors

Preserve osmotic pressure

• albumin (considered a contra-indication by some based on SAFE trial subgroup analysis)
• blood products
• diuretics

Reduce hydrostatic pressure

• metoprolol
• clonidine
• thiopentone
• dihydroergotamine (precapillary vasoconstriction)

CPP target

• if ICP normal aim for 60-70mmHg
• however, if ICP elevated a CPP of 50mmHg is accepted

Vasoactive use

• avoid dobutamine (cerebral vasodilatation)
• avoid noradrenaline (cerebral vasoconstriction)

EVIDENCE

• improved outcomes compared with historical controls and other institutions have been reported in a few nonrandomized studies
• until recently had never been subjected to a randomized trial and had never been evaluated outside Sweden
• one small Bosnian RCT found a mortality benefit for a ‘modified Lund protocol’ in TBI, compared to a CPP targetted approach
• good evidence against some components of the Lund concept protocol

References and Links

• Dizdarevic K, Hamdan A, Omerhodzic I, Kominlija-Smajic E. Modified Lund concept versus cerebral perfusion pressure-targeted therapy: a randomised controlled study in patients with secondary brain ischaemia. Clin Neurol Neurosurg. 2012 Feb;114(2):142-8. PMID: 22036839.
• Grände PO. The Lund concept for the treatment of patients with severe traumatic brain injury. J Neurosurg Anesthesiol. 2011 Oct;23(4):358-62. PMID: 21908989.
• Nordström CH. Physiological and biochemical principles underlying volume-targeted therapy–the “Lund concept”. Neurocrit Care. 2005;2(1):83-95. PMID: 16174975.
• Sharma D, Vavilala MS. Lund concept for the management of traumatic brain injury: a physiological principle awaiting stronger evidence. J Neurosurg Anesthesiol. 2011 Oct;23(4):363-7. PMID: 21908990.