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Recently, we showed the feasibility of ventilating neurosurgical patients with acute intracranial pathology and concomitant acute respiratory distress syndrome (ARDS) according the Open Lung approach. This technique consists of low tidal volume, elevated positive expiratory pressure (PEEP) level and initial recruitment maneuvers to open up collapsed alveoli. In this report, we focus on our experience to guide recruitment with brain tissue oxygenation (pO) probes.

We studied recruitment maneuvers in thirteen patients with ARDS and acute brain injury such as subarachnoid hemorrhage and traumatic brain injury. A pO probe was implanted in brain tissue at risk for hypoxia. Recruitment maneuvers were performed at an inspired oxygen frcation (FO) of 1.0 and a PEEP level of 30–40 cmHO for 40 seconds.

The mean FO necessary for normoxemia could be decreased from 0.85 ± 0.17 before recruitment to 0.55 ± 0.12 after 24 hours, while mean pO (24.6 mmHg before recruitment) did not change. At a mean of 17 minutes after the first recruitment maneuver, pO showed peak a value of 35.6 ± 16.6 mmHg, reflecting improvement in arterial oxygenation at an FO of 1.0.

Brain tissue oxygenation monitoring provides a useful adjunct to estimate the effects of recruitment maneuvers and ventilator settings in neurosurgical patients with acute lung injury.

We evaluated the effects of magnesium sulfate on brain tissue oxygen (PtO) tension, carbon dioxide (PtCO) tension and pH (pHt) in patients undergoing temporary artery occlusion for clipping of cerebral aneurysm.

We studied 18 patients with aneurysmal subarachnoid hemorrhage. All patients received standard anesthetics using target controlled infusion of propofol (3 µg/ml) and remifentanil (10 ng/ml). After craniotomy, a calibrated multiparameter sensor (Neurotrend, Diametrics Medical, Minneapolis, MN) was inserted to measure PtO, PtCO and pHt in tissue at risk of ischemia during temporary artery occlusion. Patients were then randomly allocated to receive either intravenous saline or magnesium 20 mmol over 10 min followed by an infusion 4 mmol/h. Plasma magnesium concentration, brain tissue gases and pHt were determined at baseline, 30 min after study drug infusion and 4 min after temporary clipping. Data were analyzed by factorial ANOVA with repeated measures. Intergroup difference was compared with unpaired test. value < 0.05 was considered significant.

Patient characteristics, baseline brain tissue gases and pHt did not differ between groups. Magnesium infusion increased PtO by 34%. Following temporary artery occlusion, PtO and pHt decreased and PtCO increased in both groups. However, tissue hypoxia was less severe and the rate of PtO decline was slower in the magnesium group.

Our data suggested that magnesium enhances tissue oxygenation and attenuates hypoxia during temporary artery occlusion.

We evaluated the performance of continuous intracerebral microdialysis to indicate the autoregulatory reserve in 36 severely headinjured patients. All patients received standard treatment with intracranial pressure (ICP) monitoring. A microdialysis probe was placed in the frontal cortex anterior to the ICP catheter. Perfusate was collected frequently and extracellular concentration of glutamate was measured online using enzymatic method. Autoregulatory index was calculated by comparing glutamate concentration with CPP using Pearson’s correlation. A correlation coefficient () < −0.5 is considered as loss of autoregulation, whereas r values approach 0 indicate preserved autoregulation. The change of autoregulatory status over time was correlated with outcome at 6 months.

Three patterns of autoregulatory profiles were identified. Patients with intact autoregulation had satisfactory outcome. Transient impairment of autoregulation may result in favorable outcome if patients responded to treatment. However, persistent loss of autoregulation was associated with poor outcome ( < 0.001).

The correlation between extracellular glutamate concentration (by microdialysis) and CPP is a useful index of autoregulation in head-injured patients. It predicts clinical outcome and may be used to guide therapy.

Objective of this study was to investigate the incidence, time, location, prevention, treatment and risk factors of recurrent hemorrhage in the earlier period of cerebral hemorrhage after operation. Three hundred and twenty two patients with operations in the earlier period of cerebral hemorrhage were analyzed retrospectively. The clinical data of hemorrhage and recurrent cerebral hemorrhage groups were compared and statistically analyzed. Logistic regression analysis was applied to evaluate the function of possible factors leading to recurrent hemorrhage after operation.

The incidence of recurrent hemorrhage was 21.4% in the earlier period of cerebral hemorrhage after operation. When the operation was performed after cerebral hemorrhage within 6 h, 6–12 h and 12–24 h, the incidence of recurrent hemorrhage after operation were 43.1%, 20.9%, 3.6% respectively. With regard to time of recurrent hemorrhage, the incidence was 3.1% within 12 h after operation, 15.5% between 12–24 h and just 2.8% after 24 h. Site of hemorrhage was in the basal ganglion in 92.6% of the cases. Mono-agent logistic analysis displayed that there is a significant correlation between high diastolic blood pressure, fluctuation of blood pressure after operation, taking anti-coagulant drugs for a long time, site of hemorrhage, difficult or not thorough hemostasis during operation and recurrent hemorrhage (p < 0.01). Multiple linear logistic regression analysis has shown that a remarkable diastolic blood pressure and fluctuation of blood pressure after operation are risk factors for recurrent hemorrhage. Their OR value were 10.32, 7.234. From this it is concluded that the incidence of recurrent cerebral hemorrhage after operation in the earlier period is 21.4%, which must never be ignored. The time period of 24 h after operation is a stage of high risk. Maintaining diastolic blood pressure below 85 mmHg and steadily controlling the pressure after operation are of great importance for prevention of recurrent cerebral hemorrhage.

Following aneurysmal subarachnoid haemorrhage (SAH), cerebral blood flow (CBF) may be reduced, resulting in poor outcome due to cerebral ischaemia and subsequent stroke. Hypertonic saline (HS) is known to be effective in reducing intracranial pressure (ICP) [16]. We have previously shown a 20–50% increase in CBF in ischaemic regions after intravenous infusion of HS [17]. This study aims to determine the effect of HS on CBF augmentation, substrate delivery and metabolism.

Continuous monitoring of arterial blood pressure (ABP), ICP, cerebral perfusion pressure (CPP), brain tissue oxygen (PO), middle cerebral artery flow velocity (FV), and microdialysis was performed in 14 poor grade SAH patients. Patients were given an infusion of 23.5% HS, and quantified xenon computerised tomography scanning (XeCT) was carried out before and after the infusion in 9 patients.

The results showed a significant increase in ABP, CPP, FV and PO, and a significant decrease in ICP (p < 0.05). Nine patients showed a decrease in lactate-pyruvate ratio at 60 minutes following HS infusion.

These results show that HS safely and effectively augments CBF in patients with poor grade SAH and significantly improves cerebral oxygenation. An improvement in cerebral metabolic status in terms of lactate-pyruvate ratio is also associated with HS infusion.

Idiopathic intracranial hypertension (IIH) is characterized by increased ICP without evidence for intracranial mass lesion. Although the pathogenesis remains unknown, some association was found with intracranial venous thrombosis. To our knowledge, the extracranial venous drainage was not systematically evaluated in these patients. This study compared extracranial cerebral venous outflow in eight IIH patients and eight control subjects using magnetic resonance (MR) Venography and flow measurements. In addition, the study identified extracranial factors that affect cerebral venous drainage.

In six of the IIH patients, either complete or partial functional obstruction of the internal jugular veins (IJVs) coupled with increased venous outflow through secondary venous channels was documented. On average, a four-fold increase in mean venous flow rate through the epidural and/or vertebral veins was measured in IIH patients compared with the healthy subjects.

In one of the healthy subjects, intracranial venous outflow was studied also during external compression of the IJVs. Over 40% of the venous outflow through the IJVs shifted to the epidural veins and intracranial pressure, measured noninvasively by MRI, increased from 7.5 to 13 mmHg. Findings from this study suggest that increased ICP in some IIH patients could be associated with increased extracranial resistance to cerebral venous outflow.

To our knowledge comparative studies of intracranial pressure (ICP) and degree of cerebral swelling during craniotomy for supratentorial or infratentorial space occupying lesion in children are not available. In this prospective study subdural ICP, cerebral perfusion pressure (CPP), dural tension, and the degree of cerebral swelling were analysed in supine and prone positioned children subjected to craniotomy for space occupying lesions.

. 48 children with space occupying tumours were subjected to either isoflurane/nitrous oxide 50%/ fentanyl (n = 22) or propofol/fentanyl/air/oxygen (n = 26). 25 children were operated supratentorially in supine position, while 23 patients were operated infratentorially in the prone position. Subdural ICP, mean arterial blood pressure (MABP), and CPP were measured just before opening of the dura. Dural tension was estimated before opening of dura, and the degree of cerebral swelling was estimated after opening of dura.

. The age and weight of children anaesthetised with isoflurane in the prone position were significantly lower than the propofol anaesthetised groups. No significant inter-group differences as regards tumour size, midline shift, rectal temperature, MABP or PaCO were found. ICP in prone positioned children averaged 16.9 mm Hg against 9.0 mm Hg in supine positioned children (p < 0.001). In prone positioned children the dura was significantly tenser, and the degree of brain swelling after opening of dura was significantly more pronounced. No significant difference as regard ICP was disclosed when isoflurane/nitrous oxide/fentanyl and propofol/ fentanyl anaesthetized children were compared, but MABP and CPP were significantly lower in isoflurane anaesthetised children.

. In children with cerebral tumours ICP is higher, and the degree of cerebral swelling more pronounced in the pronecompared with supine positioned children.

Choice of anaesthesia did not influence ICP, but CPP was significantly lower during isoflurane anaesthesia.