Brain PtiO2

Recombinant human erythropoietin (EPO) has been successfully tested as neuroprotectant in brain injury models. The first large clinical trial with stroke patients, however, revealed negative results. Reasons are manifold and may include side-effects such as thrombotic complications or interactions with other medication, EPO concentration, penetration of the blood-brain-barrier and/or route of application. The latter is restricted to systemic application. Here we hypothesize that EPO is neuroprotective in a rat model of acute subdural hemorrhage (ASDH) and that direct cortical application is a feasible route of application in this injury type...

Neuromonitoring in patients with severe brain trauma and stroke is often limited to intracranial pressure (ICP); advanced neuroscience intensive care units may also monitor brain oxygenation (partial pressure of brain tissue oxygen, P(bt)O(2)), electroencephalogram (EEG), cerebral blood flow (CBF), or neurochemistry. For example, cortical spreading depolarizations (CSDs) recorded by electrocorticography (ECoG) are associated with delayed cerebral ischemia after subarachnoid hemorrhage and are an attractive target for novel therapeutic approaches...

Decompressive craniectomy (DC) following brain injury can induce complications (hemorrhage, infection, and hygroma). It is then considered as a last-tier therapy, and can be deleteriously delayed. Focal neuromonitoring (microdialysis and PtiO2) can help clinicians to decide bedside to perform DC in case of intracranial pressure (ICP) around 20 to 25 mmHg despite maximal medical treatment. This was the case of a hunter, brain injured by gunshot. DC was performed at day 6, because of unstable ICP, ischemic trend of PtiO2, and decreased cerebral glucose but normal lactate/pyruvate ratio...

BACKGROUND: Lactate fuels cerebral energy-consuming processes and it is neuroprotective. The impact of arterial lactate on brain metabolism determined by microdialysis was investigated retrospectively in patients with severe traumatic brain injury (TBI). METHODS: Cerebral microdialysis (glucose, lactate), neuromonitoring (ICP, CPP, ptiO2, SjvO2) and blood gas data collected in 20 patients during pharmacologic coma were grouped within predefined arterial lactate clusters (<1, 1-2, >2 mM)...

Therapeutic interventions following severe traumatic brain injury (TBI) are substantially influenced by complex and interwoven pathophysiological cascades involving both, local and systemic alterations. Our main duty is to prevent secondary progression of the primary damage. This, in turn, obliges us to actively search and identify secondary insults related, for example, to hypoxia, hypotension, uncontrolled hyperventilation, anaemia, and hypoglycaemia. During pharmacological coma we must rely on specific cerebral monitoring which is indispensable in unmasking otherwise occult changes...

INTRODUCTION: The management of incidental unruptured aneurysms remains a matter of controversy; middle-sized or large anterior circulation incidental aneurysms, in young or middle age patients, should be considered for treatment. Surgical clipping is an accepted treatment for middle cerebral artery unruptured aneurysms. Ischemic events can occur even in cases of incidental aneurysm surgery. Since regional cerebral blood flow can be compromised due to temporary arterial clipping or to incorrect placement of defi nitive clip, we performed intra-operative monitoring of brain tissue oxygen concentration (PtiO(2)), to detect changes in brain oxygenation due to reduced blood fl ow, eventually leading to ischemia, during surgery of middle cerebral artery incidental aneurysms...

Second level therapeutic maneuvres for controlling intracranial hypertension (ICH) proposed by the European Brain Injury Consortium and the American Association of Neurological Surgeons include barbiturates, moderate hypothermia and more recently the decompressive craniectomy (DC).In most patients, ICP can be maintained below 25 mmHg after a DC. However, the exact effect of DC on brain oxygenation (PtiO2) still unclear. From our point of view the ptIo2 monitoring with the probe located in the healthy area of the most severely damaged cerebral hemisphere is not only a important tool for timing craniectomy in the future but also for evaluating the therapeutic effectivity of DC...

The traditional axiom that vasospasm induced reduction of blood flow leads to poor tissue oxygenation and ischaemic cellular injury culminating in delayed neurological deficits has been challenged and the efficacy of triple H therapy in reversal of the above is debated. In this study we assess cerebral physiology before and during onset of DIND and with application of triple H therapy with real time neuro-monitoring tools. Patients with Fisher grade 3/4/3 + 4/rebleed were consented. Probes for measuring rCBF, pTiO2, and Microdialysis parameters - glucose, glycerol, lactate, and pyruvate were inserted at time of coiling/clipping...

OBJECTIVE: The study presented evaluated the first clinical use of a new multiparameter catheter measuring intracranial pressure (ICP), partial pressure of brain tissue oxygen (ptiO2), and brain temperature (TBr) (Neurovent PTO). To assess the validity of measured ptiO2 a second probe, which represents the current golden standard of ptiO2 measurement, was implanted (Licox system). METHODS: Thirty patients with indicated invasive measurement of ICP under intensive care unit conditions were included...

Present knowledge about hemodynamic and metabolic changes after subarachnoid hemorrhage (SAH) originates from neuromonitoring usually starting with aneurysm surgery and animal studies that have been focusing on the first 1 to 3 h after SAH. Most patients, however, are referred to treatment several hours after the insult. We examined the course of hemodynamic parameters, cerebral blood flow, and tissue oxygenation (ptiO2) in the first 6 h after experimental SAH. Sixteen Sprague-Dawley rats were subjected to SAH using the endovascular filament model or served as controls (n=8)...

Local brain tissue oxygen (ptiO2) monitoring is frequently applied in patients at risk for cerebral ischemia. To identify ischemic thresholds, the normal range of local brain tissue oxygen pressure (ptiO2) values needs to be established. Ideally, such normal values are determined in healthy and awake subjects, so as to eliminate the possible influences of anesthetics on cerebral physiology or ptiO2. Thus far, however, such measurements have not been conducted, and to fill this void, we determined the ptiO2 values in normal white matter of awake patients undergoing functional stereotactic brain surgery...

OBJECTIVE: Tuberculous meningitis (TBM) is a massive global problem. The mortality and morbidity associated with the severe form of the disease are exceptionally high. Even when increased intracranial pressure is treated and full conventional therapy is commenced, cerebral ischemia can develop and is associated with a particularly poor prognosis. We sought to evaluate our experience with two patients with severe TBM and cerebral oxygenation monitoring. DESIGN: Case report...

OBJECTIVE AND IMPORTANCE: Cortical spreading depolarizations (CSD) are waves of mass tissue depolarization that mediate progressive development of cortical infarction in animal models and occur in approximately 50% of patients with acute brain injury. Here we performed multi-modal cerebral monitoring to investigate pathologies associated with CSD occurrence in a case of severe traumatic brain injury. CLINICAL PRESENTATION: A 20 years old male suffering severe traumatic brain injury from a fall had extensive frontal subdural and intraparenchymal hemorrhage with mass effect...

INTRODUCTION: Intraoperative neuromonitoring in aneurysm surgery can be very useful to determine inadequate positions of the vascular clip that cause partial or complete compromise of the cerebral sanguineous flow in the vascular territories irrigated by the arteries related to aneurysm. The direct visualization of these arteries after the application of the surgical clip can be insufficient in detecting this potentially detrimental situation. Knowing this circumstance on the onset would allow the neurosurgeon to correct it and to avoid, therefore, cerebral ischemic tissue hypoxia...

OBJECTIVE: Prolonged erythrocyte storage time might reduce the efficacy of transfusion. In this study, the effects of transfusion of erythrocytes with four different storage periods (<10 days, n = 18; 10-14 days, n = 15; 15-19 days, n = 17; and >19 days, n = 16 patients) on brain tissue oxygen tension (PtiO2) in stable male patients with severe traumatic brain injury were investigated during a 24-hr follow-up period. DESIGN: Prospective, observational study...

One of the main causes of secondary cerebral injury is cerebral hypoxia, basically of ischemic origin. However, cerebral tissue oxygenation depends on multiple physiological variables and cerebral hypoxia may be caused by an alteration of any one of them. Although several methods of continuous cerebral oxygenation monitoring of neurocritical patients have been developed, direct and continuous measurement of the oxygen pressure in the cerebral tissue (PtiO2) has been a reality in the handling of the neurocritical patients over recent years...

The aim of this study was to explore the effects of barbiturate coma on cerebral tissue oxygen tension and cerebrovascular pressure reactivity (PRx), as an index of cerebral autoregulation in severe head injury patients. This was a prospective observational clinical study of 12 patients with severe traumatic brain injury, carried out at a tertiary-level neurosurgical intensive care unit between April 2002 and May 2005. All patients received standard neurosurgical intensive care and monitoring. Probes for intracranial pressure (ICP), brain temperature (BT) and brain tissue oxygenation (PTiO2) were inserted into (noncontused) normal-looking white matter...

OBJECTIVE: To examine whether the effect of hypoxia-hypotension (HH) after traumatic brain injury (TBI) is affected by the delay between insults. DESIGN: Thirty Sprague-Dawley rats were randomized into five groups: sham, TBI alone (trauma alone, impact-acceleration, 450 g weight drop from 1.8 m), HH alone (blood depletion, mean arterial pressure 40 mmHg, FIO2=10%, 15 min), TBI+early HH (TBI followed by HH, 45-min delay), and TBI+late HH (225-min delay). Cerebral perfusion pressure was continuously recorded...

Delayed neurological deficit occurs among 30% of patients after aneurysmal subarachnoid haemorrhage, mainly related to cerebral vasospasm. The early detection of cerebral ischemia remains problematic. Conventional cerebral monitoring (as intracranial pressure and cerebral perfusion pressure) appears to be insufficient, because cerebral ischemia may occur without elevated intracranial pressure. Global cerebral monitoring as venous jugular oxygen saturation are useful for regional monitoring. Local monitoring as oxygen tissue partial pressure (PtiO2) and microdialysis are sensible for brain ischemia detection, but may also ignore episodes occurring in non-monitored brain area...

OBJECTIVE: We compared brain tissue oxygen tension (PtiO2) measured in peri-focal and in normal-appearing brain parenchyma on computerized tomography (CT) in patients following traumatic brain injury (TBI). DESIGN: Prospective observational study. SETTING: Neurointensive care unit. PATIENTS AND PARTICIPANTS: Thirty-two consecutive TBI patients were subjected to PtiO2 monitoring. INTERVENTIONS: Peri-focal tissue was identified by the presence of a hypodense area of the contusion and/or within 1 cm from the core of the contusion...