Nimodipine can improve cerebral metabolism and outcome in patients with severe head trauma
Introduction
Severe traumatic brain injury is an important public health problem with a high mortality and morbidity rate [1]. With a better understanding of the pathophysiology of traumatic brain injury, increasing effort has been applied to the development of neuroprotective measures [1], [2]. It was shown that cerebral blood flow (CBF) is decreased but oxygen consumption is increased in the acute phase after severe head trauma [3], [4], [5], [6], [7]. Treatment of cerebral ischemia may improve outcome of these patients. Secondary mechanisms, such as excitotoxicity can increase brain edema and intracranial pressure (ICP), and decrease cerebral perfusion pressure (CPP) and brain oxygenation [3], [8], [9], [10], [11], [12].
Some agents are used as neuroprotective against traumatic brain injuries [13]. One of them, L-type calcium channel blocking agent, nimodipine had been used clinically and experimentally and has been shown to dilate cerebral arterioles and to increase cerebral blood flow in humans and animals [1], [14], [15]. The neuroprotective effect of nimodipine is still not completely clear but, might be related to vasodilating, and calcium channel blocking [1], [2].
The role of intracerebral lactate after head injury has been much debated recently [3], [5]. It has been hypothesized that lactate constitutes the preferred substrate over glucose in neurons, especially in times of increased metabolism [3], [16], [17], [18], [19], [20]. This is because neurons use lactate by converting it to pyruvate which then enters the mitochondrial Krebs-cycle to produce adenosine triphosphate (ATP) synthesis [3], [21], as long as mitochondria are functioning [3], [22].
The aim of this study is to control and prevent secondary neuronal damages by giving nimodipine in the patients with severe head trauma. Therefore, CPP, jugular venous oxygen saturation (SjvO2), jugular lactate and glucose levels were measured and Glascow outcome score (GOS) was determined in all patients.
Section snippets
Materials and methods
All patients were admitted to the neurosurgical intensive care unit, examined and evaluated by Glascow coma score (GCS). A total of 10 patients who had suffered a severe head injury, with a GCS ≤ 8 were included in the study. Diffuse brain edema was determined in computerized tomographies of all patients. The patients with traumatic or chronic lung pathology, or brain lesion requiring surgical operation are excluded in this research. Again these patients had no pre-existing cardiovascular,
Results
A total of 10 patients suffering from severe head injury were studied; six males and four females in average. Patients of both groups were taken to the hospital mostly after a motor vehicle accident. In all the patients, ICP sensor and internal SjvO2 probe were placed. None of the patients were treated by any type of open surgical operation.
Demographic data for the patients who were treated without nimodipine and for patients treated with nimodipine is shown in Table 1. Demographic data were
Discussion
Traumatic brain injury patients are very heterogeneous and a wide range of factors including age, severity, mechanism types of injury and timing of initiation of treatment might significantly affect their outcome [1], [2]. The pathophysiology of traumatic brain injury is not entirely understood [1], [2]. Cerebral ischemia, glutamate release, influx of Ca2+ ions are the reasons of traumatic neurotoxicity. Neuroprotective agents targeting different pathophysiological mechanisms have been
Conclusions
The major conclusion of this study would be that the restoring effect of nimodipine in patients with severe head trauma on disordered cerebral metabolism would prevent cellular injury. This could be considered as a neuroprotective effect. The fact that neurological outcome in patients of nimodipine group is higher supports this consideration. One of the remarkable results in this study to note is that no detrimental side effect was observed related to the use of nimodipine in patients with
Study limitations
Since only the patients who had severe head trauma with a GCS ≤8 are included, and the ones with traumatic or chronic lung pathology or brain lesion which requires surgical operation are excluded in this research, total number of the patients for this study is not very high. Further studies with groups of larger samples would be necessary to investigate the effectiveness of this drug in detail.
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