Dose-response Relationship of Dexmedetomidine Combined with Sufentail for Postoperative Intravenous Analgesia in Video-assisted Thoracoscopic Surgery / 中国医学科学院学报

Objective To investigate the 50% effective dose(ED)and 95% effective dose(ED)of dexmedetomidine(DEX)combined with 0.032 μg/(kg·h)sufentanil as well as its analgesic effect for patient-controlled intravenous analgesia(PCIA)after video-assisted thoracoscopic surgery(VATS).Methods Totally 25 patients undergoing elective VATS were enrolled. DEX and 0.032 μg/(kg·h)sufentanil were used for postoperative PCIA. The loading dose of DEX was 0.048 μg/(kg·h),and the dose difference between two adjacent patients was 0.008 μg/(kg·h). The DEX dose of a current patient was determined by whether the previous patient was satisfied with postoperative analgesic effect. If the previous patient was satisfied with postoperative analgesic effect,the DEX dose of the current patient was decreased by 0.008 μg/(kg·h);and if the previous analgestic effect was not satisfactory,DEX dose of the current patient was increased by 0.008 μg/(kg·h). The study endpoint was dexmedetomidine dose was<0.008 μg/(kg· h) within 7 upper and lower cycles in 7 consecutive cases. Finally,the probability unit regression was used to estimate the ED and ED of DEX and their 95% .Results When DEX combined with 0.032 μg/(kg·h) sufentanil was used for postoperative PCIA in young patients undergoing VATS,the ED and EDof DEX were 0.0346 μg/(kg· h)[95%:0.0283-0.0408 μg/(kg·h)] and 0.0459 μg/(kg·h)[95%:0.0400-0.0880 μg/(kg·h)],respectively. No adverse reaction such as vomiting,respiratory depression,or bradycardia occurred. The average Visual Analogue Scale(VAS)scores at rest(=-5.128,=0.000)and cough(Z=-6.642,=0.000)and the Ramsay sedation score(Z=-2.335,=0.020)within 6 hours after surgery were higher than those after 6 hour.Conclusion DEX combined with 0.032 μg/(kg·h) sufentanil are effective for postoperative PCIA in patients undergoing VATS when the ED and ED are 0.0346 μg/(kg·h)and 0.0459 μg/(kg·h),respectively.

Effect of aquaporin-4 deficiency on intravenous anaesthetic induced hypnotic effects in mice / 生理学报

The deficiency of aquaporin-4 (AQP4) has been reported to alter release of neurotransmitters in the mouse brain. However, the functional relevance of AQP4 in mediating essential components of the general anaesthetic state is unknown. The aim of the present study was to investigate the role of AQP4 in general anaesthesia in mice lacking AQP4. The hypnotic effects of propofol, ketamine, and pentobarbital in AQP4 knockout (KO) and CD1 control mice were evaluated using the behavioural endpoint of loss of righting reflex (LORR). The effects of propofol on extracellular levels of amino acids in prefrontal cortex of freely moving mice were investigated using microdialysis coupled to high performance liquid chromatography with fluorescent detection. The result showed that, after receiving ketamine or pentobarbital, LORR occurred at earlier time in KO mice than that in control animals. Intraperitoneal injection of ketamine or pentobarbital increased the duration of LORR. After the administration of propofol, the duration of LORR was significantly reduced in KO mice compared with that in controls. Propofol increased the extracellular levels of aspartate, glutamate, and GABA, but not taurine, in prefrontal cortex. There were significant differences of increase patterns of the three kinds of neurotransmitters between KO and WT mice. Notably, the duration of GABA level increase correlated with the duration of LORR in two genotypes of mice. These results provide in vivo evidence of different responses in time-dependent release of excitatory and inhibitory neurotransmitters in prefrontal cortex of the two genotypes of mice. It is suggested that changes in anaesthetic reactions in mice with AQP4 loss may be related to neurotransmitter regulation, and that normal functioning of AQP4 plays an important role in the maintenance of anaesthetic hypnosis.

Protective effect of heme oxygenase-1 on lung injury induced by erythrocyte instillation in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intratracheal instillation of blood induces self-repaired acute lung injury. However, the mechanism of repair has been unclear. Heme-oxygenase (HO)-1, which catalyzes heme breakdown, acts as an inducible defense against oxidative stress and plays an important role in inflammation. The objective of this study was to test the role of HO-1 in lung injury caused by intratracheal instillation of red cells.</p><p><b>METHODS</b>Forty healthy, male Sprague-Dawley rats were randomly divided into five groups: normal group, saline group, erythrocyte group, erythrocyte+zinc-protoporphyrin (ZnPP, HO-1 inhibitor) group and saline+ZnPP group. At 2 days after intratracheal instillation of red cells, lung tissues and lavage samples were isolated for biochemical determinations and histological measurements.</p><p><b>RESULTS</b>Histological analysis revealed that administration of ZnPP worsened the acute lung injury induced by instilled erythrocytes. HO-1 was over-expressed in the erythrocyte group and in the erythrocyte + ZnPP group. Compared with the erythrocyte + ZnPP group, the levels of total protein, lactate dehydrogenase and tumor necrosis factor-alpha in the lavage were lower (P < 0.01), while the level of interleukin-10 was higher in the erythrocyte group (P < 0.01).</p><p><b>CONCLUSION</b>HO-1 protects against erythrocyte-induced inflammatory injury in lung.</p>