Propofol and α2-Agonists Attenuate Microglia Activation and Restore Mitochondrial Function in an In Vitro Model of Microglia Hypoxia/Reoxygenation.

Cerebrovascular ischemia is a common clinical disease encompassing a series of complex pathophysiological processes in which oxidative stress plays a major role. The present study aimed to evaluate the effects of Dexmedetomidine, Clonidine, and Propofol in a model of hypoxia/reoxygenation injury. Microglial cells were exposed to 1%hypoxia for 3 h and reoxygenated for 3 h, and oxidative stress was measured by ROS formation and the expression of inflammatory process genes. Mitochondrial dysfunction was assessed by membrane potential maintenance and the levels of various metabolites involved in energetic metabolism. The results showed that Propofol and α2-agonists attenuate the formation of ROS during hypoxia and after reoxygenation. Furthermore, the α2-agonists treatment restored membrane potential to values comparable to the normoxic control and were both more effective than Propofol. At the same time, Propofol, but not α2-agonists, reduces proliferation (Untreated Hypoxia = 1.16 ± 0.2, Untreated 3 h Reoxygenation = 1.28 ± 0.01 vs. Propofol hypoxia = 1.01 ± 0.01 vs. Propofol 3 h Reoxygenation = 1.12 ± 0.03) and microglial migration. Interestingly, all of the treatments reduced inflammatory gene and protein expressions and restored energy metabolism following hypoxia/reoxygenation (ATP content in hypoxia/reoxygenation 3 h: Untreated = 3.11 ± 0.8 vs. Propofol = 7.03 ± 0.4 vs. Dexmedetomidine = 5.44 ± 0.8 vs. Clonidine = 7.70 ± 0.1), showing that the drugs resulted in a different neuroprotective profile. In conclusion, our results may provide clinically relevant insights for neuroprotective strategies in intensive care units.

Tentorial Angioleiomyoma: A Rare Neurosurgical Entity. Case Report and Review of the Literature.

BACKGROUND: Angioleiomyoma (ALM) is a soft tissue neoplasm rarely described in the intracranial site. Because of their uncommon presentation, atypical neuroradiologic and pathologic features, ALMs are often misdiagnosed. CASE DESCRIPTION: We describe the neuroradiologic, clinical, and pathologic data of a 37-year-old male patient suffering from a tentorial ALM. He was admitted at our hospital because of a posterior cranial fossa mass. Magnetic resonance imaging (MRI) showed a left tentorial tumor, hypointense on T1-weighted sequences, with heterogeneous contrast enhancement after gadolinium injection ("salt-and-pepper" fashion) and slightly hyperintense signal on T2-weighted sequence. After surgery, pathological examination showed a tumor composed of several thick-walled blood vessels mixed with a population of deeply eosinophilic spindle-shaped smooth muscle cells arranged in bundles. Necrosis was absent. Neither cellular pleomorphism nor mitoses were detected. Immuno-histochemical analysis confirmed the smooth muscle phenotype of the spindle cell component: diffuse and strong positivity for alpha-smooth muscle actin, desmin, and h-caldesmon. Based on both morphologic and immunohistochemical findings, a diagnosis of primary intracranial ALM was rendered. CONCLUSIONS: We add to the literature the tenth case of this exceedingly rare tumor and submit that ALM should be suspected when a tentorial mass with a "flame-like" time-dependent pattern of contrast enhancement on MRI, a "salt-and-pepper" post-contrast appearance on MRI T1-weighted sequences, and a relation with large intracranial feeding vessels are present.

A novel anaesthetical approach to patients with brugada syndrome in neurosurgery.

Brugada syndrome (BrS) is one of the most common causes of sudden death in young people. It usually presents with life-threatening arrhythmias in subjects without remarkable medical history. The need for surgical treatment may unmask BrS in otherwise asymptomatic patients. The best anaesthesiological treatment in such cases is matter of debate. We report a case of neurosurgical treatment of cerebello pontine angle (CPA) tumor in a BrS patient, performed under total intravenous anesthesia (TIVA) with target controlled infusion (TCI) modalities, using midazolam plus remifentanil and rocuronium, without recordings of intraoperative ECG alterations in the intraoperative period and postoperative complications.

Cuff-leak test predicts the severity of postextubation acute laryngeal lesions: a preliminary study.

BACKGROUND AND OBJECTIVE: The objectives of the present study were to evaluate the relationships between the results of the cuff-leak test and the presence of laryngeal lesions; to assess whether lesions needing pharmacological treatment and surveillance can be predicted by the cuff-leak test; and to analyse the relationships between these lesions and postextubation stridor. METHODS: The present study is a preliminary, prospective, clinical investigation set in an 11-bed ICU of a university hospital. We studied 50 consecutive adult patients admitted to the ICU and mechanically ventilated for more than 72 h. All patients underwent cuff-leak test before extubation. A laryngoscopic inspection was performed after extubation to evaluate the presence and degrees of laryngeal lesions. Laryngeal lesions were classified according to a 5-degree scale (0-4); patients with clinical manifestations were pharmacologically treated and monitored. RESULTS: A threshold cuff-leak value of 0.07 l (21% of tidal volume) was determined by visual inspection of the receiver-operating characteristic plot. Patients were divided into a positive and a negative cuff-leak test group. Comparing the severity of laryngeal lesions to the cuff-leak test, a relationship between higher degrees of lesions (degrees 3-4) and the positivity of the cuff-leak test (31.3% in the positive cuff-leak test group vs. 3.8% in the negative cuff-leak test group; P = 0.023) was observed. The positive and the negative predictive values were 25 and 96.1%, respectively. Only two cases of postextubation stridor were found, one in each group. There was no correlation between the results of the cuff-leak test and the occurrence of postextubation acute respiratory difficulties. CONCLUSION: Cuff-leak test is a simple, noninvasive tool, which may be useful to exclude, in patients with prolonged intubations, the presence of laryngeal injuries needing medical treatment and close monitoring. This occurs independently of postextubation stridor.

Effect of positive expiratory pressure and type of tracheal cuff on the incidence of aspiration in mechanically ventilated patients in an intensive care unit.

OBJECTIVE: To test the effects of positive expiratory pressure on the leakage of fluid around cuffs of different tracheal tubes, in mechanically ventilated patients and in a benchtop model. DESIGN: Randomized clinical trial and experimental in vitro study. SETTING: Intensive care unit of a university hospital. PATIENTS: Forty patients recovering in the intensive care unit were ventilated in volume-controlled mode. Twenty patients were randomly intubated with Hi-Lo tubes (HL group), whereas the remaining 20 subjects were intubated with SealGuard tubes (SG group). INTERVENTIONS: Immediately after intubation and cuff inflation with 30 cm H2O, Evans blue was applied onto the cephalic surface of the tracheal tube cuff. A 5-cm H2O positive expiratory pressure was used during the first 5 hrs of stay, and thereafter it was removed. Bronchoscopy verified whether the dye leaked around the cuff. The experiment lasted 12 hrs. Leakage was also tested in vitro with the same tracheal tubes with incremental level of positive expiratory pressure. MEASUREMENTS AND MAIN RESULTS: At 1 hr, 5 hrs, and thereafter hourly until 12 hrs, bronchoscopy was used to test the presence of dye on the trachea caudal to the cuff. At the fifth hour, two patients of the HL group failed the test. One hour after positive expiratory pressure removal, all subjects in group HL exhibited a dyed lower trachea. On the other hand, one patient in group SG presented a leak at the eighth hour, and at the 12th hour three of them were still sealed. In vitro, the same level of positive expiratory pressure delayed the passage of dye around the cuff; after 30 mins positive expiratory pressure was removed, and in 10 mins all dye leaked only in the Hi-Lo tube. CONCLUSIONS: We found that 5 cm H2O positive expiratory pressure was effective in delaying the passage of fluid around the cuffs of tracheal tubes both in vivo and in vitro. The SealGuard tube proved to be more resistant to leakage than Hi-Lo.

B-type natriuretic peptide in healthy subjects after exposure to hyperbaric oxygen at 2.5 ATA.

INTRODUCTION: B-type natriuretic peptide (BNP) is a cardiac hormone used as a marker of cardiac dysfunction with diuretic and vasodilating properties secreted by the ventricles in response to wall stress. Hyperbaric oxygen (HBO) exposure is known to induce hemodynamic effects in humans which can be complicated by acute pulmonary edema. The aim of this study was to investigate if HBO has any effects on the secretion of BNP in healthy human subjects. METHODS: Eight healthy volunteers underwent the following HBO protocol in a hyperbaric chamber: compression to 2.5 atmospheres absolute (ATA); 45 min breathing 100% oxygen; 5 min breathing air; another 45 min in 100% oxygen; then decompression to atmospheric pressure. A venous blood sample was drawn before entering the chamber (To), immediately at the end of the treatment (T1), and at 5 h from To (T2). BNP concentration was determined using a rapid point-of-care immunoassay. Non-parametric statistics were used to analyze data. RESULTS: No difference in BNP levels was found between T0 and T1 or T2. DISCUSSION: The findings of this preliminary study show that in healthy subjects a single HBO exposure does not significantly modify BNP plasma levels. We hypothesize that this can be the net result between the stimulating effect of the HBO-induced vasoconstriction and the direct inhibitory effect on BNP secretion of myocyte hyperoxia. We conclude that HBO does not modify BNP secretion in healthy volunteers and that the direct effect of extreme hyperoxia on BNP secretion deserves further investigation.