Ultrasound-assisted modified paramedian technique for spinal anesthesia in elderly.

BACKGROUND: At present, there are two techniques which are widely applied clinically; the midline and the paramedian. Both methods are difficult for clinicians when treating the elderly. The aim of this work is to explore the feasibility of an ultrasound-assisted modified paramedian technique for spinal anesthesia in the elderly. This would provide clinicians with a new and easy-to-operate technique. METHODS: A total of 150 elderly patients who were scheduled for urology surgery under spinal anesthesia in our hospital were randomly divided into three groups (n = 50): (i) midline technique group (group M), (ii) paramedian technique group (group P), and (iii) modified paramedian technique group (group PM). All spinal anesthesia were performed by the same second-year resident. RESULTS: Compared with groups M and P, group PM had significantly higher first-attempt success rate (P < 0.05, especially in patients aged 65-74 years), fewer attempts (P < 0.05), and higher patient satisfaction score (P < 0.05). Compared with group M, the time taken to perform spinal anesthesia and the number of needle redirections were significantly reduced in group PM (P < 0.05). There was no statistically significant difference between groups PM and P. There were also no statistically significant differences in the cases of inconsistency between ultrasound-assisted and landmark-guided location of intervertebral space, the time taken to ultrasound-assisted location, the onset time to pain block at T10, the incidence of hypotension, anesthesia effect and the incidence of headache, lower back pain, or nausea and vomiting, within 24 h after surgery. CONCLUSIONS: The modified paramedian technique in spinal anesthesia for elderly patients can significantly improve the first-attempt success rate, reduce both the number of attempts and procedure time, and minimize tissue damage during the operation. Compared with the traditional techniques, the modified paramedian technique combines the advantages of both the midline and the paramedian methods, and is easy to learn. It is worthy of further research and application. TRIAL REGISTRATION: Prospectively registered at the China Clinical Trial Registry, registration number ChiCTR2100047635 , date of registration: 21/06/2021.

Carbenoxolone has the potential to ameliorate acute incision pain in rats.

Carbenoxolone (CBX) is primarily used to relieve various types of neuropathic and inflammatory pain. However, little is known concerning the role of CBX in acute pain and its functional mechanisms therein and this was investigated in the present study. Rats underwent toe incision and behavioral tests were performed to assess mechanical hypersensitivity. The expression levels of pannexin 1 (Px1) and connexin 43 (Cx43) were detected using western blot analysis 2, 4, 6 or 24 h after toe incision, and the expression of TNF­α, IL­1ß and P substance (SP) was determined by ELISA; Px1 and Cx43 expression was also examined by immunofluorescence staining. At 2, 6 and 12 h post­toe incision, the postoperative pain threshold was significantly reduced, which was subsequently recovered at 2 and 6 h post­surgery following pretreatment with CBX or pannexin 1 mimetic inhibitory peptide. CBX reduced Px1 levels at 4 and 24 h post­incision. However, Cx43 levels were reduced by CBX as little as 2 h post­surgery. Furthermore, CBX not only distinctly decreased the levels of Px1 and Cx43, but also reduced the co­localization of Px1 or Cx43 with glial fibrillary acidic protein, 2 h after incision. It was also observed that the protein levels of inflammatory makers (IL­1ß, SP and TNF­α) showed a tendency to decline at 2, 4, 6 and 24 h after incision. Collectively, the expression of Px1 and Cx43 in astrocytes may be involved in pain behaviors diminished by CBX, and CBX potentially reduces acute pain by decreasing Px1 and Cx43 levels. Px1 and Cx43 from spinal astrocytes may serve important roles in the early stages and maintenance of acute pain, while preoperative injection of CBX has the potential to relieve hyperalgesia.

Propentofylline reduces mechanical allodynia and induces mitogen-activated protein kinase phosphatase-1: An experimental study in a rat model of acute incisional pain.

Background: Acute postoperative pain can lead to long hospital stays, dysfunction, and even chronic pain. Mitogen-activated protein kinases (MAPKs) are important in pain signaling. The activity of MAPKs are negatively regulated by dual specificity phosphatases such as mitogen- activated protein kinase phosphatase-1 (MKP-1), which specifically dephosphorylates MAPK p38. Since, propentofylline (PPF) can reduce pain by inhibiting MAPKs, we hypothesized that PPF relieves acute pain by inducing MKP-1 levels. Objective: Investigating the anti-nociception effect of an intrathecal injection of PPF in a rat model of acute incisional pain and the role of MKP-1 and phospho-p38 in the mechanism by which PPF ameliorates acute pain. Methods: We assessed the mechanical withdrawal threshold (MWT) response before and after incisional pain surgery between a control group and a group receiving PPF, and also assessed the effect of pre-treatment with Ro 31-8220, an MKP-1 inhibitor, on PPF effects. Following the MWT, lumbar spinal cord samples were also analyzed by western blot analysis to determine MKP-1 and p-p38 levels. Results: Following surgery, the MWT response was decreased over 5 h-3 d accompanied by decreased expression of MKP-1 and increased p-p38 levels. An intrathecal injection of PPF increased the MWT response and increased spinal cord MKP-1 expression, but decreased p-p38 levels. Pre-treatment of rats with Ro31-8220 partly reversed the analgesic effect of PPF and its effect on MKP-1/p-p38 levels. Conclusions: This study suggests that an increase in MKP-1 levels and a corresponding decrease in p-p38 levels may be the mechanism by which PPF ameliorates acute pain.

Establishment and Validation of a Prediction Equation to Estimate Risk of Intraoperative Hypothermia in Patients Receiving General Anesthesia.

Inadvertent intraoperative hypothermia (core temperature <36 °C) is a frequent but preventable complication of general anesthesia. Accurate risk assessment of individual patients may help physicians identify patients at risk for hypothermia and apply preventive approaches, which include active intraoperative warming. This study aimed to develop and validate a risk-prediction model for intraoperative hypothermia. Two independent observational studies in China, the Beijing Regional Survey and the China National Survey, were conducted in 2013 and 2014, respectively, to determine the incidence of hypothermia and its underlying risk factors. In this study, using data from these two studies, we first derived a risk calculation equation, estimating the predictive risk of hypothermia using National Survey data (3132 patients), then validated the equation using the Beijing Regional Survey data (830 patients). Measures of accuracy, discrimination and calibration were calculated in the validation data set. Through validation, this model, named Predictors Score, had sound overall accuracy (Brier Score = 0.211), good discrimination (C-Statistic = 0.759) and excellent calibration (Hosmer-Lemeshow, P = 0.5611). We conclude that the Predictors Score is a valid predictor of the risk of operative hypothermia and can be used in deciding whether intraoperative warming is a cost-effective measure in preventing the hypothermia.

Intraoperative hypothermia and its clinical outcomes in patients undergoing general anesthesia: National study in China.

BACKGROUND/OBJECTIVE: Inadvertent intraoperative hypothermia (core temperature <36°C) is a frequently preventable complication with several adverse consequences. Our study aimed to determine the overall incidence of inadvertent intraoperative hypothermia and its risk factors associated with clinical outcomes in this national survey in China. METHODS: We conducted a national cross-sectional study with 30 days postoperative follow-up from November 2014 through August 2015. A total of 3132 eligible patients underwent general anesthesia were randomly selected from 28 hospitals in the nationwide of China. RESULTS: The overall incidence of intraoperative hypothermia was as high as 44.3%, in which cumulative incidence rates of hypothermia being 17.8%, 36.2%, 42.5% and 44.1% within 1 h, 2 h, 3 h and 4 h respectively following induction of anesthesia. All patients were warmed passively by covering of surgical draping, sheets or cotton blankets, whereas only 14.2% of patients received active warming with space heaters or electric heater or electronic blankets. Compared to normothermic patients, patients with hypothermia is associated with more postoperative ICU admit, longer PACU and more postoperative hospital days, but no difference in surgical site infection (SSI) rates or 30-day mortality. Several factors were shown to be associated with decreased risk of hypothermia. They are active warming (OR = 0.46, 95% CI 0.26-0.81), BMI ≥ 25 (OR = 0.54, 95% CI 0.45-0.65), higher baseline core temperature (OR = 0.04, 95% CI 0.03-0.06), and higher ambient temperature (OR = 0.83, 95% CI 0.78-0.88). Risk factors associated with an increased risk of hypothermia included major-plus surgery (OR = 1.49, 95% CI 1.23-1.79), and long anesthesia (>2 h) (OR = 2.60, 95% CI 2.09-3.24). CONCLUSIONS: The incidence of intraoperative hypothermia in China is high, and the rate of active warming of patients during operation is low. Hypothermia is associated with more postoperative shivering, increased ICU admissions, and longer postoperative hospital days.

µ-Opioid agonists for preventing emergence agitation under sevoflurane anesthesia in children: a meta-analysis of randomized controlled trials.

BACKGROUND: Emergence agitation (EA) is an adverse effect after sevoflurane anesthesia in pediatric patients. The effectiveness of prophylactic µ-opioid agonists fentanyl, remifentanil, sufentanil, and alfentanil in preventing EA is debatable. METHODS: A literature search was conducted to identify clinical trials that observed the effect of µ-opioid agonists fentanyl, remifentanil, sufentanil, and alfentanil on preventing EA in pediatric patients under sevoflurane anesthesia. The statistical software RevMan 5.3 was used for meta-analysis. Data from each study were combined using the relative ratio (RR), weighted mean differences, and their associated 95% confidence intervals. I(2) was used to evaluate heterogeneity. Subgroup analysis was conducted to investigate the possible influences of patient age, adenotonsillectomy, premedication, N2 O, propofol, and regional block/local anesthetics on preventing EA with prophylactic administration of µ-opioid agonists. Publication bias was checked using funnel plots and Begg's test. RESULTS: This meta-analysis showed the inclusion of 19 randomized controlled trials with 1528 patients (857 patients received µ-opioid agonists therapy and 671 patients had placebo). The pooled data indicated that prophylactic µ-opioid agonists fentanyl, remifentanil, sufentanil, and alfentanil significantly decreased the incidence of EA [RR = 0.49 (0.38, 0.64), I(2) = 42%, P = 0.04; RR = 0.57 (0.33, 0.99), I(2) = 37%, P = 0.19; RR = 0.18 (0.08, 0.39), I(2) = 0%, P = 0.98; and RR = 0.56 (0.40, 0.78), I(2) = 6%, P = 0.34, respectively]. All subgroup analyses strengthened the proof for lower incidence of EA under sevoflurane anesthesia after fentanyl administration. A possibility of publication bias was detected in the fentanyl group. CONCLUSIONS: This meta-analysis suggested that prophylactic µ-opioid agonists fentanyl, remifentanil, sufentanil, and alfentanil could significantly decrease the incidence of EA under sevoflurane anesthesia in children compared to placebo. Considering the limitations of the included studies, more clinical studies are required.

[Effects of ketamine and splenectomy on cognition and synaptic plasticity in hippocampus of senile rats].

OBJECTIVE: To study the effects of ketamine anesthesia and surgery on cognition and synaptic structure in hippocampus of senile rats. METHODS: Fifty-six rats aged 18 months were randomly divided into 3 groups: Groups C (control group), A (ketamine 40 mg/kg, i.p.) and O (ketamine anesthesia & splenectomy). Morris water maze test was used to observe cognition at Days 1, 3 & 7 after ketamine anesthesia or operation respectively. Accordingly Groups A and O were divided into 3 subgroup, i.e. A1, A3, A7 and O1, O3, O7. The time of Morris water maze test was recorded and the synaptic structure was measured in the polymorphic layer of the rat hippocampal field CA3. RESULTS: Compared to Group C, the latency period and swimming distance significantly increased in Groups A1, O1 and O3 (P < 0.05), and the numbers passing the original platform decreased significantly in Groups O1 and O3 (P < 0.01). The latency period was significantly longer in Group O1 than that in Group A1 (P < 0.05) while the swimming distance was unchanged. Compared to Group C, the width of synaptic cleft (P < 0.01) increased, the length and area of postsynaptic densities (P < 0.05 or P < 0.01) as well as synaptic curvature (P < 0.01) decreased in Groups O1 and O3. The percentage of perforated synapses also decreased in Groups O1 and O3. CONCLUSION: Surgical injury can impair cognition of senile rats and the synaptic plasticity might be involved in postoperative cognitive dysfunction.