Remimazolam dosing for intraoperative sedation in elderly patients undergoing hip replacement with combined spinal-epidural anesthesia

OBJECTIVE

The aim of the study was to investigate the 50% and 95% effective doses (ED50 and ED95) of remimazolam for intraoperative sedation in elderly patients undergoing hip replacement with combined spinal-epidural anesthesia (CSEA).

PATIENTS AND METHODS

We retrospectively analyzed the clinical data of 50 patients who underwent hip replacement with CSEA in our hospital from October 2021 to June 2022. There were 29 males and 21 females, aged 60-80 years old, with body mass indexes (BMI) ranging from 18 to 24 kg/m2, and American Society of Anesthesiologists (ASA) classifications of I or II. The modified Dixon sequential method was used to determine the dose of remimazolam for each patient. Each patient's initial dose was 0.1 mg/kg/h, and the dose gradient was 0.01 mg/kg/h. The bispectral index (BIS) and the modified observer's assessment of alertness/sedation score (MOAA/S) were used to evaluate the sedation of the patient. An MOAA/S score ≤3 and a BIS <85 at three or more time points during surgery indicated the sedation was satisfactory. The induction dose of the next patient was adjusted by 0.01 mg/kg/h based on the level of sedation achieved, and the study was terminated after eight crossovers.

RESULTS

The ED50 and ED95 of remimazolam for sedation of elderly patients undergoing hip replacement with CSEA are 0.212 mg/kg/h (95% CI: 0.121-0.231 mg/kg/h) and 0.288 mg/kg/h (95% CI: 0.254-0.884 mg/kg/h), respectively. Two patients experienced transient bradycardia, five experienced hypoxemia, three experienced postoperative nausea, and three experienced postoperative delirium. No patients experienced adverse reactions such as injection pain, hypotension, vomiting, delayed awakening, or emergence agitation.

CONCLUSIONS

The ED50 and ED95 of remimazolam for sedation of elderly patients undergoing hip replacement with CSEA are 0.212 mg/kg/h and 0.288 mg/kg/h, respectively.

Comparison of the treatment effects of methoxamine and combining methoxamine with atropine infusion to maintain blood pressure during spinal anesthesia for cesarean delivery: a double blind randomized trial

OBJECTIVE

Hypotension is a common complication of spinal anesthesia for cesarean delivery. Atropine is a vagus nerve blocker that can antagonize vagus excitation to mitigate the reflex bradycardia. We aimed to assess the effect of methoxamine-atropine therapy in treating spinal anesthesia hypotension for cesarean section.

PATIENTS AND METHODS

This is a double-blind randomized controlled study. Women under spinal anesthesia for elective caesarean delivery received boluses of methoxamine 2 mg alone (Group M, n = 40), or with addition of atropine 0.1 mg (Group MA1, n = 40), atropine 0.2 mg (Group MA2, n = 40) or atropine 0.3 mg (Group MA3, n = 40) upon a maternal systolic pressure ≤ 80% of baseline. The primary endpoint was systolic blood pressure and the secondary endpoints were maternal heart rates, instant neonatal heart rates, umbilical artery pH and umbilical artery base excess.

RESULTS

Changes in systolic blood pressure were similar among the four groups. The incidences of bradycardia in groups M and MA1 were significantly higher than those in group MA2 and MA3. The fetal heart rates after delivery in groups MA2 and MA3 were higher than those in group M and MA1 but within the normal range. The acid-base status had no difference in the four groups.

CONCLUSIONS

Methoxamine-atropine combination has a similar efficacy to methoxamine alone but has an increased hemodynamic stability and a less adverse effect occurrence.

Clinical features and risk factors of creatine kinase elevations and myopathy associated with telbivudine

With the extensive use of telbivudine, more and more studies reported its association with creatine kinase (CK) elevations and myopathy. However, clinical features of these adverse effects were poorly understood. The aim of the present study was to investigate the clinical features and risk factors of CK elevations and myopathy associated with telbivudine. The serum CK levels of 200 patients who were treated with telbivudine for chronic hepatitis B (CHB) between January 2007 and July 2010 were monitored and analysed along with clinical manifestations. The 3-year cumulative incidence of CK elevations and myopathy was 84.3% and 5%, respectively. CK elevations occurred more frequently in men than in women, and patients aged ≤45 years and with negative HBeAg had higher incidence of CK elevations. There was no difference in CK elevations among patients with different HBV DNA levels. Male, younger age and HBeAg negativity were independent predictors of CK elevations by multivariate Cox regression analysis. There was no association between the occurrence of myopathy and variables including age, sex, HBeAg and HBV DNA. No risk factors of myopathy were identified. CK elevations usually occurred 21 months after starting treatment, and most patients resolved spontaneously without interruption of telbivudine therapy except three patients who had to switch to other agents. In conclusion, CK elevations are common adverse reactions associated with telbivudine therapy, while myopathy is rare. Male, younger age and HBeAg negativity might be risk factors of CK elevations.