Intravenous administration of flurbiprofen does not affect cerebral blood flow velocity and cerebral oxygenation under isoflurane and propofol anesthesia

Comparison of intravenous sedation using midazolam versus dexmedetomidine in elderly patients with dementia: a randomized cross-over trial

Differences between the effects of intravenous sedation with midazolam (MID) and dexmedetomidine (DEX) on the cerebral function of elderly patients with severe dementia are unclear. This study aimed to compare the effects of intravenous sedation with MID or DEX on parameters such as brain waves and cerebral blood flow (CBF). This cross-over study analyzed 12 patients with severe dementia, with each patient receiving both drug treatments. Each drug was administered until a Modified Observer’s Assessment of Alertness/Sedation (OAA/S) score of 2 was reached. Bispectral index (BIS) and normalized tissue hemoglobin index (nTHI), which reflects CBF using near-infrared spectroscopy, were measured. Mann–Whitney U, Wilcoxon signed-rank, and Friedman tests, and multiple regression analysis were performed. While a similar decline in BIS values was observed in both groups (P < 0.030), there was a significant decrease in nTHI up to 11% in the MID group (P = 0.005). In the DEX group, nTHI values did not differ from baseline. When an OAA/S score of 2 was just achieved, CBF in the MID group (− 5%) was significantly lower than in the DEX group (± 0%). In dementia patients, sedation with MID resulted in a decrease in CBF, while the CBF value was maintained during sedation with DEX.

Effect of desflurane on changes in regional cerebral oxygenation in patients undergoing one-lung ventilation is equivalent to the effect of propofol

OBJECTIVES

Desaturation is an important clinical problem during one-lung ventilation (OLV) since it may induce cerebral hypoxia. Measurement of cerebral oxygenation has been shown to provide accurate information about episodes of cerebral hypoxemia. The purpose of this study was to compare the effect of desflurane on changes in cerebral oxygenation during OLV with the effect of propofol.

METHODS

A randomized, single-blinded, prospective study was conducted. Fifty adult patients who were scheduled to undergo thoracic surgery were randomly assigned to anesthetic management using desflurane with remifentanil (Group D: n = 25) or using propofol and remifentanil (Group P: n = 25).

RESULTS

The characteristics of the patients were very similar. Intergroup analysis of changes in cerebral oxygenation showed no significant difference on the operative side (two-way ANOVA, F (7, 368) = 0.425, p = 0.887) or the non-operative side (two-way ANOVA, F (7, 367) = 1.342, p = 0.229). Intragroup analysis of changes in cerebral oxygenation using one-way ANOVA showed no significant difference on the operative side (Group P; p = 0.585, Group D; p = 0.928) or the non-operative side in both groups (Group P; p = 0.657, Group D; p = 0.602).

CONCLUSIONS

The effects of desflurane and propofol on changes in cerebral oxygenation in patients undergoing OLV were equivalent. Our results indicated that desflurane might be an appropriate anesthetic during OLV for maintaining cerebral oxygenation with an effective equivalent to that of propofol.

Action of β-endorphin and nonsteroidal anti-inflammatory drugs, and the possible effects of nonsteroidal anti-inflammatory drugs on β-endorphin

This study aimed to review research on the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on β-endorphin. NSAIDs are commonly used as anti-inflammatory and analgesic drugs. They are well known for inducing peripheral analgesia by inhibiting cyclooxygenase (COX). However, an increasing number of studies have shown that NSAIDs have an analgesic effect not only in the periphery but also at the center. It means that a central analgesic mechanism of the action of NSAIDs exists besides the peripheral mechanism, and the central mechanism likely involves β-endorphin. β-Endorphin is one of the most prominent endogenous peptides, existing in the hypophysis cerebri and hypothalamus. It plays an irreplaceable role in the central and peripheral analgesia in the human body mainly through three mechanisms including three parts, the spinal cord, the supraspinal cord, and peripheries. β-Endorphin plays an important role in the development of hyperalgesia. However, the specific signal transduction pathways between prostaglandin E₂ or NSAIDs and β-endorphin are still not quite clear. Whether NSAIDs can lead to the increased content of β-endorphin in all patients after any operation needs further investigation. Further studies should determine the optimal dose when NSAIDs and opioid drugs are used together, and also explore the existence of one NSAID that has the potential to replace the traditional opioid drugs and can achieve adequate analgesia.

Sedation agents differentially modulate cortical and subcortical blood oxygenation: evidence from ultra-high field MRI at 17.2 T

BACKGROUND

Sedation agents affect brain hemodynamic and metabolism leading to specific modifications of the cerebral blood oxygenation level. We previously demonstrated that ultra-high field (UHF) MRI detects changes in cortical blood oxygenation following the administration of sedation drugs commonly used in animal research. Here we applied the UHF-MRI method to study clinically relevant sedation drugs for their effects on cortical and subcortical (thalamus, striatum) oxygenation levels.

METHODS

We acquired T2*-weighted images of Sprague-Dawley rat brains at 17.2T in vivo. During each MRI session, rats were first anesthetized with isoflurane, then with a second sedative agent (sevoflurane, propofol, midazolam, medetomidine or ketamine-xylazine) after stopping isoflurane. We computed a T2*-oxygenation-ratio that aimed at estimating cerebral blood oxygenation level for each sedative agent in each region of interest: cortex, hippocampus, thalamus and striatum.

RESULTS

The T2*-oxygenation-ratio was consistent across scan sessions. This ratio was higher with inhalational agents than with intravenous agents. Under sevoflurane and medetomidine, T2*-oxygenation-ratio was homogenous across the brain regions. Intravenous agents (except medetomidine) induced a T2*-oxygenation-ratio imbalance between cortex and subcortical regions: T2*-oxygenation-ratio was higher in the cortex than the subcortical areas under ketamine-xylazine; T2*-oxygenation-ratio was higher in subcortical regions than in the cortex under propofol or midazolam.

CONCLUSION

Preclinical UHF MRI is a powerful method to monitor the changes in cerebral blood oxygenation level induced by sedative agents across brain structures. This approach also allows for a classification of sedative agents based on their differential effects on cerebral blood oxygenation level.

Comparison of changes in jugular venous bulb oxygen saturation and cerebral oxygen saturation during variations of haemoglobin concentration under propofol and sevoflurane anaesthesia

BACKGROUND

A severe reduction in haemoglobin concentration can lead to a decrease in jugular venous bulb oxygen saturation (Sj(O(2))). However, recent evidences suggests that cerebral oxygen saturation (Sc(O(2))) measured by near infrared spectroscopy decreased during even mild haemodilution. We therefore tested the hypothesis that the changes in Sc(O(2)) may not be parallel to those in Sj(O(2)) during haemodilution. In addition, as cerebral oxygen balance during the operation can vary depending on the anaesthetics used, the changes in Sj(O(2)) and Sc(O(2)) during haemodilution were compared between patients under propofol and isoflurane/nitrous oxide anaesthesia.

METHODS

Forty-two patients with pre-donated autologous blood were randomly assigned to receive propofol (Group P) or sevoflurane/nitrous oxide (Group S) anaesthesia. A fibreoptic catheter was placed in the jugular bulb to measure Sj(O(2)). A cerebral oximeter, INVOS 4100S was used to monitor Sc(O(2)). Arterial and jugular bulb blood samples were drawn simultaneously at: (i) 10 min after the start of operation, (ii) after 400 ml of blood loss, (iii) after 800 ml of blood loss, (iv) just before the transfusion of pre-donated autologous blood, and (v) after 400 ml transfusion.

RESULTS

Mean (sd) control values of Sj(O(2)) in Group P were significantly lower than those in Group S (55 (8)% vs 71 (10)%, respectively; P<0.05), whereas there was no significant difference in control values of Sc(O(2)) between the two groups. During the operation, haemoglobin (Hb) concentrations significantly deceased in the both groups compared with control values (from 9.8 to 7.6 g dl(-1) in Group P and from 9.9 to 8.0 g dl(-1) in Group S). During a reduction in Hb concentration, Sj(O(2)) values remained unchanged in both groups, whereas Sc(O(2)) values significantly decreased in both groups (from 57 to 51% in Group P and from 59 to 52% in Group S).

CONCLUSION

The results indicated that, although the changes in Sj(O(2)) and Sc(O(2)) during a reduction in haemoglobin concentration were similar under propofol and sevoflurane/nitrous oxide anaesthesia, the changes in Sc(O(2)) were not parallel to those in Sj(O(2)). The discrepancy of the results in Sj(O(2)) and Sc(O(2)) may make the interpretation of their values difficult during haemodilution.

Gastroprotective effect and mechanism of amtolmetin guacyl in mice

AIM: To investigate the gastroprotective effect and mechanism of amtolmetin guacyl (AMG, MED15) in mice.

METHODS: Male and female Kunming strain mice, weighing 18-22 g, were utilized in the experiment. Normal or ethanol-induced gastric mucosal damage models in mice were successfully established to investigate the gastroprotective effect and mechanism of AMG. In the experiment of gastric mucosal damage after repeated treatment with AMG, the mice were randomly divided into 5 groups: normal group, 3 AMG groups receiving (75, 150 and 300 mg/kg), and tolmetin group receiving 90 mg/kg. The mice were randomly divided into 6 groups as follows: normal group, model group, AMG groups with doses of 75, 150 and 300 mg/kg, respectively, and tolmetin group with a dose of 90 mg/kg in ethanol-induced gastric mucosal damage experiment. The severity of gastric mucosal lesions was scored from 0 to 5. Gastric tissue sections were stained with hematoxylin and eosin (HE) and examined under light microscopy. Also gastric tissue sections were stained with uranyl acetate and lead citrate, and examined under electron microscopy. In addition, nitric oxide (NO) and malondialdehyde (MDA) contents, and nitric oxide synthase (NOS) and superoxide dismutase (SOD) activities in the stomach tissue homogenates were measured by biochemical methods.

RESULTS: Repeated treatment with AMG (75, 150 and 300 mg/kg) for 7 d did not induce any appreciable mucosal damage, and the average score was not significantly different from that of normal mice. In contrast, tolmetin (90 mg/kg) produced significant gastric mucosal lesions compared with the normal group (P < 0.01). AMG (75, 150 and 300 mg/kg) significantly reduced the severity of gastric lesions induced by ethanol in a dose-dependent manner as compared with the model group (P < 0.05, AMG 75 and 150 mg/kg vs model; P < 0.01, AMG 300 mg/kg vs model). Light and electron microscopy revealed that AMG (150 and 300 mg/kg) induced minimal changes in the surface epithelium layer, without vascular congestion or leucocyte adherence. AMG (75, 150 and 300 mg/kg) demonstrated dose-dependent gastroprotective effects on mice in our study. AMG (75, 150 and 300 mg/kg) could significantly increase NO content and NOS level in the stomach homogenates of mice compared with the model group (P < 0.05, AMG 75 mg/kg and 150 mg/kg groups vs model group; P < 0.01, AMG 300 mg/kg vs model group) respectively. Moreover, AMG (150 and 300 mg/kg) not only significantly increased SOD activities but also obviously decreased the MDA content in the stomach homogenates of mice.

CONCLUSION: AMG exerts significant gastroprotective actions on mice and the involved mechanisms may be its antioxidative effect and induction of NO production.