Effects of dexmedetomidine dosage on the short-term cognitive function of elderly patients undergoing cardiac surgery.

BACKGROUND: This study aimed to investigate the effects of perioperative dexmedetomidine (DEX) infusion rates on the postoperative short-term cognitive function. METHODS: A total of 88 patients aged ≥ 60 years who underwent cardiac surgery from January 2022 to November 2022 at the First Affiliated Hospital of The University of Science and Technology of China (USTC) were included. Based on a single-center pilot analysis, patients were divided into two groups according to the rate of intraoperative DEX infusion, which started after tracheal intubation and continued until 1 h before extubation in the cardiac surgery intensive care unit. In Group L (n = 44), the infusion rate was 0.1-0.5 µg/kg/h (low-dose group), whereas in Group H (n = 44), the infusion rate was 0.5-0.9 µg/kg/h (high-dose group). Clinical outcomes were then compared between the groups. The Mini-Mental State Evaluation (abbreviated as MMSE1, MMSE2, MMSE3, and MMSE4) scale was used for the assessment of cognitive function, which was conducted on postoperative Days 2 (T1), 7 (T2), 14 (T3), and 28 (T4), with the score from postoperative Day 2 (MMSE1) considered as the primary observation. RESULTS: Patients in Group L had higher MMSE1 scores compared to those in Group H (26.0 [24.0, 27.0] vs. 24.5 [22.0, 26.0], p = 0.046), and there was no significant difference in the scores between the groups at all subsequent time points. Group H exhibited a higher incidence of hypotension and bradycardia compared to Group L (p = 0.044 and p = 0.047, respectively). CONCLUSIONS: Compared to a high dose (0.5-0.9 µg/kg/h) of DEX infusion, a low-dose (0.1-0.5 µg/kg/h) infusion started after induction of anesthesia and continued until 1 h before extubation improved postoperative cognitive function scores on postoperative Day 2 in patients aged 60 years and older. TRIAL REGISTRATION: URL: www.chictr.org.cn with registration number ChiCTR2100055093, registered on 31/12/2021.

Comparison of Adrenaline and Dexmedetomidine in Improving the Cutaneous Analgesia of Mexiletine in Response to Skin Pinpricks in Rats.

BACKGROUND: Adrenaline (Adr) and dexmedetomidine (Dex) are commonly used adjuvants of local anesthetics; however, the difference in the improvement of analgesia of local anesthetics between the 2 adjuvants remains unclear. OBJECTIVE: The objective of this experimental research was to evaluate the cutaneous analgesic effect of mexiletine (Mex) by coadministration with Dex or Adr. METHODS: The effect of a nociceptive block was assessed based on the inhibition of the cutaneous trunci muscle reflex in response to skin pinpricks in rats. The analgesic activity of Mex alone and Mex coadministered with Dex or Adr was evaluated after subcutaneous injections. Subcutaneous injections of drugs or combinations include Mex 0.6, 1.8, and 6.0 µmol; Adr 13.66 nmol; Dex 1.05600 nmol; saline; and Mex 1.8 and 6.0 µmol, respectively, combined with Dex 0.01056, 0.10560, and 1.05600 nmol or Adr 0.55, 2.73, and 13.66 nmol, with each injection dose of 0.6 mL. RESULTS: Subcutaneous injections of Mex elicited dose-related cutaneous analgesia. Compared with Mex (1.8 µmol), adding Dex or Adr to Mex (1.8 µmol) solutions for skin nociceptive block potentiated and prolonged the action. Mex (6.0 µmol) combined with Dex or Adr extended the duration of cutaneous analgesia when compared with Mex (6.0 µmol) alone. A high dose of Adr is more effective with Mex 1.8 µmol than that of Dex, whereas medium and low doses were less effective. Mex 6.0 µmol combined with any dose of Adr is superior to that of Dex. CONCLUSIONS: Both Dex and Adr improve the sensory block and enhance the nociceptive block duration of Mex. But in most cases, Adr is superior to Dex. It may be that different mechanisms of action of the 2 adjuvants lead to the differences.

The efficacy of pedicle screw instrument in treatment of irreducible atlantoaxial dislocation.

OBJECTIVE: To explore the effect of pedicle screw instrument in treatment of irreducible atlantoaxial dislocation. PATIENTS AND METHOD: From June 2003 to February 2009, 14 cases of atlas dislocation with upper cervical cord compression were enrolled and anterior transoral soft tissue release combined with posterior reduction and pedicle screw fixation were performed. CT, MRI and radiograph were used preoperatively, and screw placement and bone graft were administered in all cases intraoperatively. Cervical collars were used for 3 months. RESULTS: Screws were successfully placed in atlas in all cases. The average follow-up period was 18 months. Bone fusion was observed in all cases without the following complications: neurologic symptoms, internal fixation failure and redislocation. Neurological recovery was observed in all 14 cases. CONCLUSIONS: Pedicle screw instrument has the following advantages in atlas and axis injury treatment: direct screw placement, short-segment fusion, intraoperative reduction and high fusion rate, which should be a better surgical method for the treatment of atlantoaxial dislocation.

Effects of short-term preoperative intranasal dexmedetomidine plus conventional treatment on delirium following cardiac surgery in patients with sleep disorders.

STUDY OBJECTIVES: To assess whether preoperative dexmedetomidine (DEX) nasal drips combined with conventional treatment could mitigate the occurrence of postoperative delirium (POD). DESIGN: A prospective randomised controlled study. SETTING: The cardiac surgery intensive care unit (CSICU) and patient hospitalisation ward at a university hospital. PARTICIPANTS: A total of 100 patients (aged ≥60 years) undergoing cardiac surgery at a university hospital between 7 January 2022, and 30 November 2022 met the eligibility criteria and were included in the study. INTERVENTIONS: Patients with sleep disorders (Pittsburgh Sleep Quality Index ≥8) were divided into two groups: Group A (the placebo group, n=50), receiving a short-term preoperative placebo combined with conventional treatment and Group B (the DEX group, n=50), receiving short-term preoperative DEX combined with conventional treatment. MEASUREMENTS AND RESULTS: The Confusion Assessment Method for the ICU (CAM-ICU) was used for POD assessment in the CSICU, while the CAM was employed to assess delirium in the patient ward. Group B demonstrated a reduced incidence of POD compared to Group A (12% vs. 30%, odds ratio: 0.318, 95% confidence interval: 0.112-0.905, p=0.027). CONCLUSION: The combined treatment involving DEX demonstrated a decreased incidence of POD in elderly individuals with sleep disorders undergoing cardiac surgery compared to the placebo combination treatment. TRIAL REGISTRATION: URL: www.chictr.org.cn with registration number ChiCTR 2100043968, registered on 06/03/2021.

Efficacy and Complications of Unilateral Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis: A Meta-Analysis and Systematic Review.

OBJECTIVE: As an emerging minimally invasive endoscopic technique, unilateral biportal endoscopic spinal surgery (UBESS) has the advantages of flexibility, a wide and clear field of view, and less soft tissue damage. However, the clinical evidence is insufficient and controversy exists regarding UBESS for the treatment of lumbar spinal stenosis (LSS). In the present meta-analysis, we investigated the clinical efficacy and complications of UBESS for the treatment of LSS. METHODS: The PubMed, Embase, Web of Science, and Cochrane Library databases were searched through to June 1, 2021 to identify all reported studies on UBESS for LSS. Only English-language studies with original reported data from ≥30 cases were considered for inclusion. The patient demographics, operative time, hospital stay, complications, visual analog scale (VAS) score, Oswestry disability index, and Macnab criteria were extracted. Quality assessment was performed using the Cochrane collaboration tool for randomized controlled trials and the Newcastle-Ottawa scale for retrospective studies. A meta-analysis was performed using a random or fixed effect model according to the heterogeneity. RESULTS: Thirteen studies with 586 patients and 607 operation levels were included. The mean single-level operative time, hospital stay, and follow-up duration were 61.10 minutes, 2.32 days, and 14.7 months, respectively. At the final follow-up visit, the mean VAS score for leg pain had decreased from 7.23 preoperatively to 1.83 postoperatively, the mean VAS score for back pain had decreased from 6.30 to 1.95, and the mean Oswestry disability index had significantly improved from 56.99 to 17.83. The average satisfied outcome (excellent or good using the Macnab criteria) was 86%. The overall complication rate was 5%, and the most common complication was a dural tear, with an incidence of 2%, followed by epidural hematoma with an incidence of 1%. The remaining complications were nerve root injury, inadequate decompression, and postoperative headache. CONCLUSIONS: From the available clinical results and experience from reported studies, UBESS for LSS is a feasible and effective approach and a worthwhile choice for clinicians. However, the complications associated with the procedure should also be seriously considered.

Effect of Transcutaneous Electrical Acupoint Stimulation Combined with Transversus Abdominis Plane Block on Postoperative Recovery in Elderly Patients Undergoing Laparoscopic Gastric Cancer Surgery: A Randomized Controlled Trial.

INTRODUCTION: This study assessed the influence of transcutaneous electrical acupoint stimulation (TEAS) combined with transversus abdominis plane block (TAPB) on the recovery of elderly patients undergoing laparoscopic gastric cancer surgery. METHODS: Ninety patients (age ≥ 60 years) undergoing laparoscopic gastric cancer surgery were randomly divided into general anesthesia group (group G), TAPB group (group NG), and TEAS combined with TAPB group (group NTG). Patients in the NTG group received TEAS at PC6, LI4, and ST36 acupoints and TAPB. Patients in the NG group received TAPB. The quality of recovery (QoR) was assessed using the QoR-15 questionnaire. The percentages of T lymphocyte subsets were determined. Consumption of anesthetics, extubation time, visual analog scale (VAS) scores, time of first postoperative ambulation and flatus, and postoperative adverse events were also recorded. RESULTS: QoR-15 scores on postoperative day (POD) 3 and POD 7 were higher in the NTG group than in the G and NG groups (P < 0.05). On POD 1 and POD 3, the percentages of CD3+ and CD4+ T cells and the CD4+/CD8+ ratio were higher and the percentage of CD8+ T cells was lower in the NTG group than in the G and NG groups (P < 0.05). Remifentanil consumption, and the incidence of postoperative nausea and vomiting (PONV) were lower and extubation time and time of first postoperative flatus were shorter in the NTG group than in the G and NG groups (P < 0.05). Compared with the G group, the VAS scores on POD 1 were lower in the NG group and those on POD 2 were lower in the NTG group (P < 0.05). CONCLUSION: The combination of TEAS and TAPB ameliorated postoperative pain, improved immune and gastrointestinal function, reduced the incidence of PONV, and effectively promoted postoperative recovery in elderly patients undergoing laparoscopic gastric cancer surgery. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2100042119).

Dexmedetomidine Protects Human Renal Tubular Epithelial HK-2 Cells against Hypoxia/Reoxygenation Injury by Inactivating Endoplasmic Reticulum Stress Pathway.

OBJECTIVE: The study was aimed to investigate the effects and potential mechanisms of Dexmedetomidine (Dex) on hypoxia/reoxygenation (H/R) injury in human renal tubular epithelial HK-2 cells. MATERIALS AND METHODS: In this experimental study, HK-2 cells were divided into four groups: control group, Dex group, H/R group, and Dex+H/R group. The cells in control group received no treatment, and cells in Dex group were only treated with 0.1 nmol/L Dex. The cells in H/R group and Dex+H/R group were all treated with H/R (hypoxia for 24 hours and normoxia for 4 hours), and only the cells in Dex+H/R group were pre-administrated with 0.1 nmol/L Dex. Following treatments at 37˚C for 28 hours, cell viability and apoptosis were measured by MTT assay and flow cytometry, respectively. Also, the expressions of hypoxia-inducible factor 1 (HIF-1α), glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), caspase-12 and cleaved caspase-3 were determined by western blot. RESULTS: The cell viability was significant decreased in H/R group compared with control group (P<0.05), while was significantly increased in Dex+H/R group compared with that in H/R group (P<0.05). However, the change tendency of the cell apoptosis was opposite to that of cell viability. Compared with H/R group, the expression of HIF-1α was evidently up-regulated, while GRP78, CHOP, capase-12 and cleaved caspase-3 expressions were all obviously downregulated in Dex+H/R group (P<0.05). In addition, the concentrations of malondialdehyde (MDA) in H/R group and Dex+H/R group were 1.68 ± 0.22 nmol/mgprot and 0.85 ± 0.16 nmol/mgprot, respectively. The superoxide dismutase (SOD) activity was higher in Dex+H/R group (121 ± 11 U/L), which which was more than twice larger than that in H/R group (57 ± 10 U/L). CONCLUSION: Dex could promote cell viability and inhibit apoptosis through up-regulating HIF-1α, reducing endoplasmic reticulum (ER) stress and mediating oxidative stress, thus ameliorating the H/R injury.

A comparative study of serotonin and norepinephrine as adjuncts to improve cutaneous antinociception of mexiletine in response to skin pinpricks in rats.

As adrenaline, serotonin and norepinephrine are two other vasoconstrictors and both of which have been proved to increase the quality and duration of local anesthetics when added as adjuvants. However, the difference in the improvement of the nociception of local anesthetics between the two adjuvants remains unclear. The purpose of this study was to assess the cutaneous nociception of mexiletine by coadministration with serotonin and norepinephrine. Subcutaneous injection of drugs or combinations includes mexiletine 0.6, 1.8, 6.0 µmol, serotonin 1.6500 µmol, noradrenaline 0.8895 nmol, saline, mexiletine 1.8 and 6.0 µmol, respectively combined with serotonin 0.4125, 0.8250, 1.6500 µmol and noradrenaline 0.0356, 0.1779, 0.8895 nmol, with each injection dose of 0.6 ml. The nociception of mexiletine alone and mexiletine coadministered with serotonin and norepinephrine was assessed after subcutaneous injection. Subcutaneous injections of mexiletine elicited dose-related cutaneous antinociception (P < 0.05, 0.01, or 0.001). Compared with mexiletine (1.8 µmol), adding norepinephrine (except for lowest dose) and serotonin to mexiletine (1.8 µmol) solutions for skin nociceptive block potentiated and prolonged the action (P < 0.01 or 0.001). Mexiletine (6.0 µmol) combined with norepinephrine and serotonin extended the duration of cutaneous antinociception when compared with mexiletine (6.0 µmol) alone (P < 0.05, 0.01, or 0.001). Both serotonin and norepinephrine improve the sensory block and enhances the nociceptive block duration of mexiletine, and serotonin is superior to that of norepinephrine.

The effect of dexmedetomidine on renal function in patients undergoing cardiac valve replacement under cardiopulmonary bypass: A double-blind randomized controlled trial.

STUDY OBJECTIVE: We attempted to explore the effect of Dex on renal function in patients with cardiac valve replacement under cardiopulmonary bypass (CPB). DESIGN: We designed a prospective, randomized, placebo-controlled, single-center, parallel-arm double-blind trial. SETTING: Operating room. PATIENTS: Seven-two eligible patients were randomly divided into Dex group and placebo group. INTERVENTIONS: Dexmedetomidine (Dex) (0.6µg·kg-1) was administered in patients of Dex group at 15min before anesthesia induction, followed by a treatment of 0.2µg·kg-1·h-1 Dex until the end of operation. Patients in placebo group were treated with normal saline equally. MEASUREMENTS: The levels of serum urea nitrogen (BUN), creatinine (Cr), neutrophil gelatinase-associated lipocalin (NGAL), urine interleukin-8 (IL-18) and superoxide dismutase (SOD) activity were tested before anesthesia induction (T1) and after operation at 0, 12h, 24h and 72h (T2-5). The urine output during operation and the post-operative complication of acute kidney injury (AKI) were recorded. MAIN RESULTS: The levels of BUN and Cr were significantly increased at T5, and similar findings were found in the levels of NGAL and urine IL-18 at T3 and T4. The SOD activity was significantly declined at T2 and T3 in the two groups. The levels of BUN and Cr at T5 and the NGAL level at T3 and T4 were significantly lower in Dex group, comparable to placebo group. The intraoperative urine output was significantly increased and the postoperative incidence of AKI was significantly lower in Dex group. CONCLUSIONS: Dex may attenuate the renal injury and decrease the incidence of AKI in patients undergoing cardiac valve replacement under CPB.