Dexmedetomidine Improves Locomotor Function and Alleviates Thermal Hyperalgesia Following Sciatic Nerve Crush Injury in Rats.

PURPOSE: The effects of dexmedetomidine on locomotor function and thermal hyperalgesia in sciatic nerve crush injury (SNCI) were investigated using rats. METHODS: After exposing the right sciatic nerve, the sciatic nerve was crushed for 1 minute by a surgical clip. One day after nerve injury, dexmedetomidine (5, 25, and 50 µg/kg) was directly applied to the injured sciatic nerve once a day for 14 days. Walking track analysis was used to assess locomotor function and plantar test was conducted to assess thermal pain sensitivity. Immunohistochemistry was performed to determine the expression of c-Fos in the ventrolateral periaqueductal gray (vlPAG) and paraventricular nucleus (PVN). Western blot was used to evaluate the expression level of nerve growth factor (NGF) and myelin basic protein (MBP) in the sciatic nerve. RESULTS: SNCI resulted in deterioration of locomotor function and increased thermal pain sensitivity. The level of c-Fos expression in the PVN and vlPAG was increased and the level of NGF and MBP expression in the sciatic nerve was enhanced by SNCI. Dexmedetomidine treatment improved locomotor function and upregulated expression of NGF and MBP in the sciatic nerve of SNCI. Dexmedetomidine treatment alleviated thermal hyperalgesia and downregulated expression of c-Fos in the vlPAG and PVN after SNCI. CONCLUSION: Dexmedetomidine may be used as a potential new treatment drug for recovery of locomotion and control of pain in peripheral nerve injury.

The relationship of preoperative estimated glomerular filtration rate and outcomes after cardiovascular surgery in patients with normal serum creatinine: a retrospective cohort study.

BACKGROUND: Although serum creatinine concentration has been traditionally used as an index of renal function in clinical practice, it is considered relatively inaccurate, especially in patients with mild renal dysfunction. This study investigated the usefulness of preoperative estimated glomerular filtration rate (eGFR) in predicting complications after cardiovascular surgery in patients with normal serum creatinine concentrations. METHODS: This study included 2208 adults undergoing elective cardiovascular surgery. Preoperative eGFR was calculated using Chronic Kidney Disease Epidemiology Collaboration equations. The relationships between preoperative eGFR and 90 day postoperative composite major complications were analyzed, including 90 day all-cause mortality, major adverse cardiac and cerebrovascular events, severe acute kidney injury, respiratory and gastrointestinal complications, wound infection, sepsis, and multi-organ failure. RESULTS: Of the 2208 included patients, 185 (8.4%) had preoperative eGFR < 60 mL/min/1.73 m2 and 328 (14.9%) experienced postoperative major complications. Multivariable logistic regression analyses showed that preoperatively decreased eGFR was independently associated with an increased risk of composite 90 day major postoperative complications (adjusted odds ratio: 1.232; 95% confidence interval [CI]: 1.148-1.322; P <  0.001). eGFR was a better discriminator of composite 90 day major postoperative complications than serum creatinine, with estimated c-statistics of 0.724 (95% CI: 0.694-0.754) for eGFR and 0.712 (95% CI: 0.680-0.744) for serum creatinine (P = 0.008). CONCLUSIONS: Decreased eGFR was significantly associated with an increased risk of major complications after cardiovascular surgery in patients with preoperatively normal serum creatinine concentrations.

Postoperative Blood Loss and Coagulation Changes After Balanced 6% Hydroxyethyl Starch 130/0.4 Administration During Spine Surgery: A Retrospective Study.

STUDY DESIGN: Retrospective analysis. OBJECTIVE: The objective of this study was to investigate the effects of intraoperative balanced 6% hydroxyethyl starch (HES) 130/0.4 on postoperative blood loss and the coagulation profile. SUMMARY OF BACKGROUND DATA: The safety of colloid versus crystalloid transfusion for bleeding and coagulation during major spine surgery remains controversial and only a few studies exist. Thus, we compared the effects of balanced 6% HES 130/0.4 and crystalloid on postoperative bleeding and coagulation. METHODS: Patients undergoing spine surgery between February 1, 2015 and February 28, 2017 were divided into 2 groups: patients receiving intraoperative balanced 6% HES 130/0.4 and patients receiving crystalloid. We compared the postoperative bleeding volume with changes in the coagulation profile and length of hospital stay between these 2 groups. Propensity score (PS)-matching and multivariate stepwise linear regression were performed. RESULTS: A total of 169 patients who met the inclusion criteria were analyzed. The quantity of total colloid per patient was 10-15 mL/kg. A significant difference was observed in the total intraoperative transfused crystalloid volume between the 2 groups (colloid group, 1.394.6±1.414.0 mL; crystalloid group, 2.027.3±1.114.1 mL; P<0.001). Postoperative blood loss and coagulation profile changes were not significantly different in the 60 PS-matched paired patients. Furthermore, no differences in either postoperative transfusion requirement or length of hospital stay were observed between the groups. Multivariate stepwise linear regression revealed that operation time (ß=0.549; P<0.001) and intraoperative transfusion of packed red blood cells (ß=0.466; P=0.003) or fresh frozen plasma (ß=-0.263; P=0.041) were independently associated with postoperative blood loss. However, intraoperative colloid administration was not a predictive factor. CONCLUSIONS: Intraoperative infusion of balanced 6% HES 130/0.4 in patients undergoing spine surgery presented clinically insignificant changes in postoperative blood loss and coagulation compared to crystalloid. LEVEL OF EVIDENCE: Level III.

Association Between Arterial Carbon Dioxide Tension and Outcome in Patients Admitted to the Intensive Care Unit After Coronary Artery Bypass Surgery.

OBJECTIVES: The aim of this study was to determine the association between PaCO2 and patient outcome in patients admitted to the intensive care unit (ICU) after coronary artery bypass grafting (CABG). DESIGN: A retrospective cohort study. SETTING: Single-institutional, university hospital. PARTICIPANTS: All patients admitted to the ICU after CABG between January 2009 and December 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Based on PaCO2 status during the first 24 hours after CABG, 1,011 patients were classified into 4 groups: normocapnia, hypocapnia, hypercapnia, and dual hyper/hypocapnia. The 30-day mortality rate was 0.7% (n = 4) for normocapnia, 1.5% (n = 4) for hypocapnia, 2.2% (n = 3) for hypercapnia, and 7.5% (n = 4) for the dual-exposure group. The extubation times were 13.3±21.7 hours, 15.8±21.37 hours, 21.79±39.70 hours, and 42.29±75.35 hours, respectively. After adjusting for confounding variables, the dual hypocapnia and hypercapnia exposure group was associated with increased 30-day mortality (odds ratio [OR] = 8.08; 95% confidence interval [CI], 1.82-35.86; p = 0.006) and delayed extubation (OR = 2.40; 95% CI, 1.24-4.64; p = 0.010). CONCLUSIONS: Exposure to both hypocapnia and hypercapnia within 24 hours after CABG was associated independently with increased risk of 30-day mortality and delayed extubation. Exposure to either hypocapnia or hypercapnia alone was not associated with patient outcome.

Dexmedetomidine promotes the recovery of the field excitatory postsynaptic potentials (fEPSPs) in rat hippocampal slices exposed to oxygen-glucose deprivation.

Dexmedetomidine (DEX), a selective α2 adrenergic agonist, is an anesthetic and sedative agent, and is reported to exert neuroprotective effects after hypoxic ischemia. However, there are few studies on the electrophysiological effect of DEX in hippocampal slices under ischemic conditions. The effects of DEX on field potential in hippocampal slices exposed to oxygen-glucose deprivation (OGD) were evaluated. Hippocampal slices were prepared from rats, and the evoked field excitatory postsynaptic potentials (fEPSPs) were recorded using the MED 64 system. Hypoxic-ischemia was induced by perfusion with glucose-free artificial cerebrospinal fluid (aCSF) bubbled with 95% N2 and 5% CO2, and hippocampal slices were perfused with DEX-added aCSF before, during, and after OGD induction. In the normal hippocampal slices, perfusion with 1 and 10µM DEX did not significantly decrease the normalized fEPSP amplitude, but 100µM DEX significantly reduced the fEPSP amplitude compared with its baseline control. The induction of OGD remarkably decreased the fEPSP amplitude, whereas the pre-, co-, and post-treatment of 10µM DEX gradually promoted recovery after washing out, and consequently the amplitude of fEPSP in DEX pre-, co-, and post-treated OGD slices were significantly higher than that in the untreated OGD slices at 10min and 60min after washing out. In particular, co-treatment with DEX conspicuously promoted the recovery of the fEPSP amplitude at the beginning of washing out. These results suggest the possibility of DEX as a therapeutic agent to prevent hypoxic-ischemic brain damage and promote functional recovery after ischemia.

Treadmill exercise improves motor coordination through ameliorating Purkinje cell loss in amyloid beta23-35-induced Alzheimer's disease rats.

Alzheimer's disease (AD) is a most common age-related neurodegenerative disease. AD is characterized by a progressive loss of neurons causing cognitive dysfunction. The cerebellum is closely associated with integration of movement, including motor coordination, control, and equilibrium. In the present study, we evaluated the effect of tread-mill exercise on the survival of Purkinje neurons in relation with reactive astrocyte in the cerebellum using Aß25-35-induced AD rats. AD was induced by a bilateral intracerebroventricular (ICV) injection of Aß25-35. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 4 weeks, starting 2 days after Aß25-35 injection. In the present results, ICV injection of Aß25-35 deteriorated motor coordination and balance. The number of calbindin-positive cells in the cerebellar vermis was decreased and glial fibrillary acidic protein (GFAP) expression in the cerebellar vermis was increased in the Aß25-35-induced AD rats. Treadmill exercise improved motor coordination and balance. Treadmill exercise increased the number of Purkinje neurons and suppressed GFAP expression in the cerebellar vermis. The present study demonstrated that treadmill exercises alleviated dysfunction of motor coordination and balance by reduction of Purkinje cell loss through suppressing reactive astrocytes in the cerebellum of AD rats. The present study provides the possibility that treadmill exercise might be an important therapeutic strategy for the symptom improvement of AD patients.

Age and gender are important considerations in choosing the sniffing position for laryngoscopic view.

AIMS: The sniffing position is considered to be the standard position for direct laryngoscopic viewing. This crossover study evaluated age and gender as variables in comparing the benefits of the sniffing position over simple head extension for laryngeal view during direct laryngoscopy. METHODS: Laryngoscopy with a curved blade was performed on 200 anesthetized adults (100 males, 100 females) presenting for routine elective surgery. Glottic visualization was assessed by using the percentage of glottic opening (POGO) score in both simple extension and sniffing positions without the aid of the assistant or external laryngeal manipulation. Each gender group was divided into a younger group (< 50 years) and an older group (≥ 50 years). POGO scores were compared between both positions within each group. RESULTS: Mean (SD) POGO scores increased significantly only in younger male patients from 43% (39%) in the head extension position to 76% (30%) in the sniffing position. CONCLUSION: The sniffing position seems to be advantageous for getting a better laryngeal view during laryngoscopy for tracheal intubation in adult male patients less than 50 years old.

Endotracheal tube intubation with the aid of a laryngeal mask airway, a fiberoptic bronchoscope, and a tube exchanger in a difficult airway patient: a case report.

A 28-year-old male patient with occipito-atlanto-axial instability underwent a cervical fusion with posterior technique. Post-operatively, the endotracheal tube (ETT) was removed, and the patient was transferred to the intensive care unit. After transfer, an upper airway obstruction developed and reintubations with a laryngoscope were attempted but failed. We inserted a #4 proseal laryngeal mask airway (LMA) and passed a 5.0 mm ETT through the LMA with the aid of a fiberoptic bronchoscope. We passed a tube exchanger through the 5.0 mm ETT and exchanged it with a 7.5 mm ETT. This method may be a useful alternative for difficult tracheal intubations.