Traumatic brain injury
The Lund Concept: Although still controversial, there is a convergence of guidelines regarding TBI treatment
Traumatic brain injury (TBI) is the main cause of accidental death in Europe and all highly developed countries, accounting for around 40% of all accidental mortality.
Often, such injuries also cause permanent invalidity. Road traffic accidents are the most common cause by far. Around 20-30% of patients with severe TBI have intracranial bleeding or impression fractures that necessitate neurosurgical intervention. More than 70% of patients with traumatic brain injuries can be treated conservatively, which why intensive care plays a key role in TBI treatment.
To understand TBI treatment it is important to know that primary and secondary brain damage can be differentiated. During the development of a delayed secondary injury the post-traumatic cerebral under-perfusion of the tissue (ischaemia) plays a decisive role. The cerebral perfusion pressure (CPP), defined as mean arterial pressure (MAP) minus intracranial pressure (ICP), together with cerebral vascular resistance are the physiological variables that control cerebral blood flow (CBF) and metabolic supply. Therefore, there is a close link between CPP and ischaemia.
There are currently very different views about the level of the necessary cerebral perfusion pressure. The guidelines from the European Brain Injury Consortium (EBIC) and the American Association of Neurological Surgeons (AANS) recommend a CPP targeted treatment as ischaemia and hypoxia (lack of adequate oxygen supply) of the brain are considered to be main factors of post-traumatic brain swelling. For a long time this was the accepted treatment approach. However, the high mortality rate of this treatment made Dr Per-Olof Grände and his neurosurgical colleague Dr Carl-Henrik Nordström, at the University Hospital in Lund, look for an alternative.
The alternative he developed is based on the basal physiology for brain volume and brain circulation. The main objective is to prevent an increase in intracranial pressure (ICP) and thus improve the perfusion and oxygenation of the injured brain areas. Unlike the conventional guidelines, with their meta-analytical approach, Per-Olof Grände’s team did not want to accept high blood pressure in the brain: ‘The American guidelines even recommend the administration of catecholamines to increase blood pressure in the brain, but with the Lund Concept we do the opposite. We administer antihypertensive treatment to lower the blood pressure, because we assume that an increase in blood pressure goes hand in hand with increased cerebral oedema,’ Dr Grände pointed out.
The most important parts of the concept were proven in animal research and clinical studies. In the first study in the early 1990s, 45 patients were treated according to the new concept. Result: Mortality for severe TBI was lowered from 40 to below 15%.
Other studies also confirm a better clinical outcome for patients. However, the Lund Concept still remains controversial, mainly because most studies were not randomised. ‘Only one study from China, published in 2010, was carried out using a control group. This study also showed a tendency similar to the other studies,’ he said.
Meanwhile, according to Dr Grände both approaches have converged somewhat. Whilst the conventional guidelines originally recommended a CPP minimum of 70 mm Hg, they have since been changed because of the bad outcome for patients. ‘The US guidelines from 2007 give almost the same recommendations with regards to CPP as we do with the Lund Concept,’ he explained. Therefore, nowadays there is a clear convergence with the Lund Concept not only regarding CPP but also for many other aspects of TBI treatment.’
PROFILE
Professor Per-Olof Grände gained his MSc in technical science in 1969, PhD in circulatory physiology in 1979, and graduated as a medical doctor in 1981, from Lund University, Sweden. In 1986 he became a specialist in anaesthesia and intensive care and in 2002, took the role of Professor for Anaesthesia and Intensive Care at Lund University Hospital.
His research has focused on circulatory physiology, head trauma and sepsis, while his circulatory physiology study has concentrated on control systems of the peripheral circulation and particularly mechanisms controlling transvascular fluid exchange. An important part of his research has dealt with the Lund Concept to treat severe brain trauma.
06.03.2013
