European journal of anaesthesiology. Supplement
-
The most informative neurophysiological techniques available in the neurosurgical intensive care unit are electroencephalograph and somatosensory evoked potentials. Such tools, which give an evaluation of cerebral function in comatose patients, support clinical evaluation and are complementary to neuroimaging. They serve both diagnostic/prognostic and monitoring purposes. ⋯ While somatosensory evoked potentials correlated with short-term outcome, intracranial pressure showed a poor correlation. We believe neurophysiological monitoring is an ideal complement to the other parameters monitored in the neurosurgical intensive care unit. Whereas intracranial pressure is simply a pressure index, electroencephalograph-somatosensory evoked potential monitoring reflects to what extent cerebral parenchyma still remains metabolically active during acute brain injury.
-
Eur J Anaesthesiol Suppl · Jan 2008
ReviewDoes ICP monitoring make a difference in neurocritical care?
Raised intracranial pressure and low cerebral perfusion pressure are associated with ischaemia and poor outcome after brain injury. Therefore, many management protocols target these variables. However, there are no randomized controlled trials that have demonstrated the effectiveness of intracranial pressure-guided care in severely head-injured patients. ⋯ Furthermore, intracranial pressure monitoring and aggressive management of intracranial pressure and cerebral perfusion pressure have been associated with increased lengths of stay in the neurocritical care unit, conceivable costs and possibly an increased rate of complications. Against this background, there is sufficient clinical equipoise to warrant an adequately powered randomized controlled trial to compare intracranial pressure-guided care with supportive critical care without intracranial pressure monitoring in patients with severe traumatic brain injury. However, the realization of such a trial is likely to be problematic for a number of reasons, not least of which the firmly held biases of many clinicians.
-
Transcranial Doppler is an innovative, flexible, accessible tool for the bedside monitoring of static and dynamic cerebral flow and treatment response. Introduced by Rune Aaslid in 1982, it has become indispensable in clinical practice. The main obstacle to ultrasound penetration of the skull is bone. ⋯ Brain death is defined as the irreversible cessation of all functions of the whole brain. The clinical criteria are usually considered sufficient to establish a diagnosis of brain death; however, they might not be sufficient in patients who have been on sedatives or when there are ethical or legal controversies. Many authors have demonstrated the existence of a transcranial Doppler pattern, which is typical of brain death.
-
Eur J Anaesthesiol Suppl · Jan 2008
ReviewEffects of catecholamines on cerebral blood vessels in patients with traumatic brain injury.
Data on the cerebrovascular effects of catecholamines after head injury are difficult both to interpret and to compare. Diverse parameters with regard to brain trauma animal models, methods of determining the effects on the cerebral blood flow and metabolism and choice of end-points have been used. Many studies investigate the cerebrovascular effects of catecholamines over a range of cerebral perfusion pressures above the range recommended by current guidelines. ⋯ For all other catecholamines and related substances there are insufficient data on the cerebrovascular effects after head injury. This suggests that norepinephrine may be the catecholamine that is the most suitable substance to maintain or restore adequate cerebral perfusion. The data, however, are insufficient to formulate a guideline.
-
Eur J Anaesthesiol Suppl · Jan 2008
ReviewDoes multimodality monitoring make a difference in neurocritical care?
In spite of the many tools available for monitoring the central nervous system, there are no clinical trials which prove that continuous monitoring of any single variable in the intensive care unit has had any significant impact on the outcome of patients. Even in the absence of robust evidence proving the efficacy of neuromonitoring tools, we believe it is time to re-examine the basic objectives of neuromonitoring. The main reasons for monitoring neurocritical patients could be summarized as follows: (1) to detect early neurological worsening before irreversible brain damage occurs; (2) to individualize patient care decisions; (3) to guide patient management; (4) to monitor therapeutic response of some interventions and to avoid any consequent adverse effects; (5) to allow clinicians to be able to understand the pathophysiology of complex disorders; (6) to design and implement management protocols; and (7) to improve neurological outcome and quality of life in survivors of severe brain injuries. ⋯ In this review, the obstacles confronted in running randomized clinical trials in this field are discussed. The lack of equipoise and the ethical concerns in conducting such trials are discussed. In addition, the reasons for failure to improve outcome through the use of some monitoring devices are discussed and potential solutions proposed.