Neuroanaesthesia and Neurointensive Care

Intracranial pressure (Monitoring and imaging) Part 2

Measurement techniques of intracranial pressure In sedated patients with TBI, continuous ICP monitoring is recommended, and can only be achieved by direct invasive measurement. he indications for ICP monitoring are discussed below. Different methods of monitoring ICP have been described. he gold standard for ICP monitoring is a catheter inserted into the lateral ventricle (usually […]

Intracranial pressure (Monitoring and imaging) Part 3

Intracranial pressure waveforms Intracranial pressure waveforms include distinct periodic components: heart pulse waves, respiratory waves and quasi-periodic slow vasogenic waves (Lundberg B waves). Every waveform has its characteristic frequency (heart rate 50-180 bpm, respiratory waves 8-20 cycles min-1 and slow waves 0.3-3 cycles min-1), and can be identified using spectral analysis . By definition, a […]

Intracranial pressure (Monitoring and imaging) Part 4

Protocols: cerebral perfusion pressure (CPP)-, intracranial pressure- and ‘optimal CPP’-oriented therapy He continuous measurement of ICP is an essential modality in brain monitoring systems. After a decade of enthusiastic attempts to introduce newer modalities for brain monitoring (e.g. tissue oxygenation, microdi-alysis, cortical blood flow, TCD and jugular bulb oxygen saturation), ICP monitoring remains a robust […]

Bedside measurements of cerebral blood flow (Monitoring and imaging) Part 1

Introduction Monitoring cerebral blood flow (CBF) continues to be a long-standing challenge in the neurocritical care unit. he tight flow-metabolism coupling associated with normal brain function is often disturbed following brain injury, and alteration in blood flow not aligned to changes in metabolism may exacerbate secondary neuronal inj ury. Patients with traum atic brain injury […]

Bedside measurements of cerebral blood flow (Monitoring and imaging) Part 2

Laser Dopplerflowmetry Laser Doppler flowmetry (LDF) is based on the assessment of Doppler shift of low-power laser light, which is scattered by moving red blood cells (RBCs) (Fig. 5.5). Briefly, monochromatic laser light, with a wavelength above the maximal absorption of haemoglobin and below the maximal absorption of water (600-780 nm), is delivered to and […]

Cerebral oxygenation (Monitoring and imaging) Part 1

Introduction Maintaining the balance between cerebral metabolic supply and demand underpins much of neurocritical care and neuroanaesthetic practice. Cerebral perfusion pressure (CPP) and metabolic rate can be manipulated by a number of means, but these are not benign interventions and do not guarantee the absence of regional oxygenation deficits. A bedside technique for the quantitative, […]

Cerebral oxygenation (Monitoring and imaging) Part 2

Clinical applications Monitoring of cerebral oxygenation in critical care Jugular venous saturation below 50% suggests a relative failure of oxygen supply compared with demand, and such episodes have been demonstrated to predict poor outcome after head injury in a dose-dependent way. Low SjO2 is often seen in comatose patients with head injuries or subarachnoid haemorrhage, […]

Cerebral oxygenation (Monitoring and imaging) Part 3

Clinical applications A number of studies have investigated NIRS in patients with carotid occlusive disease. Vernieri and colleagues used NIRS to measure cerebral carbon dioxide reactivity and found differences between symptomatic and asymptomatic patients. Intraoperative NIRS during carotid endarterectomy demonstrated cerebral desat-uration in 50% of patients after internal carotid artery cross-clamping. Cerebral oxygen saturation has […]

Brain tissue biochemistry (Monitoring and imaging) Part 1

Introduction Cerebral microdialysis is a well-established laboratory tool that was introduced into clinical practice in the mid 1990s. It is now widely used as a bedside monitor of brain tissue biochemistry to identify cerebral hyp-oxia/ischaemia and assess cellular bioenergetics after brain injury. This topic will review the principles of cerebral microdialysis and identify its role […]

Brain tissue biochemistry (Monitoring and imaging) Part 2

Bedside microdialysis markers As any molecule that is small enough to pass across the dialysis membrane can be sampled, microdialysis is a universal biosensor with many potential applications. his section will review the substances commonly analysed at the bedside. he research applications, investigating a myriad of other substances, will be considered later in this topic. […]