Determination of ED50 and time to effectiveness for intrathecal hydromorphone in laboring patients using Dixon's up-and-down sequential allocation method

95% effective volume of ropivacaine for ultrasound‑guided supra‑inguinal fascia iliaca compartment block

BACKGROUND

Hip arthroplasty is effective in treating hip diseases, such as osteoarthritis and hip fracture, but it often brings severe trauma and pain. In recent years, ultrasound-guided supra-inguinal fascia iliaca compartment block(S-FICB) has become a widely used nerve block method for analgesia in hip arthroplasty.

METHODS

Fifty-three patients preparing for hip arthroplasty were prospectively enrolled. S-FICB was performed under ultrasound guidance, and inject 0.33% ropivacaine into the space. Using the biased-coin design (BCD) sequential allocation method. The initial volume of 0.33% ropivacaine was 30ml. In case of failure, the next patient received a higher volume (defined as the previous volume with an increment of 1.2 mL). If the previous patient had a successful block, the next patient was randomized to a lower volume (defined as the previous volume with a decrement of 1.2 mL), with a probability of b = 0.05, or the same volume, with a probability of 1 - b = 0.95. The study was stopped when 45 successful blocks were achieved.

RESULTS

Forty-five patients (84.9%) were blocked successfully. The 95% effective volume (EV95) was 34.06ml (95%CI 33.35 ~ 36.28ml). There were 31 patients with non-fracture in this study. The quadriceps muscle strength decreased in only two patients. Moreover, they both received 34.8ml of ropivacaine for S-FICB. Twenty-two patients had hip fractures. There were 3 patients (14%) with failed blocks and 19 patients (86%) with successful blocks. However, all fracture patients experienced less pain after S-FICB.

CONCLUSION

EV95 of 0.33% ropivacaine for ultrasound-guided S-FICB was 34.06ml.

TRIAL REGISTRATION

The trial was registered at the Chinese Clinical Trial Registry (registration number: ChiCTR2100052214, registration date: 2021 October 22).

The 50% and 95% effective doses of remimazolam tosilate with adjuvant sufentanil for sedation in patients with liver cirrhosis undergoing oesophagogastric varices screening endoscopy

WHAT IS ALREADY KNOWN AND OBJECTIVE

Sedation is routinely provided for patients undergoing gastrointestinal endoscopy. Remimazolam tosilate is a novel and short-acting sedative agent that has been used for sedation during endoscopic procedures. The optimal dose of remimazolam in gastrointestinal endoscopy for patients with liver cirrhosis has not been elucidated.

BACKGROUND

To determine the effective dose of remimazolam tosilate with adjuvant sufentanil for sedation in patients with liver cirrhosis undergoing oesophagogastric varices screening endoscopy.

MATERIAL AND METHODS

Patients aged 18-65 years with liver cirrhosis undergoing screening endoscopy for oesophagogastric varices were recruited. Sufentanil 0.15 μg/kg was given intravenously at 2 min before administration of remimazolam tosilate. The initial dose of remimazolam was 0.1 mg/kg and adjusted by 0.025 mg/kg as a step size, based on the Dixon and Massay up-and-down sequential method. Inclusion of patients was stopped after eight crossovers and the calculated median effective dose (ED₅₀ ) of remimazolam for successful endoscopy was obtained by calculating the mean of midpoint of all crossovers. Furthermore, a probit regression was applied to establish the dose-response curve of remimazolam and further assess the 95% effective dose (ED₉₅ ) of remimazolam.

RESULTS

The calculated ED₅₀ of remimazolam for successful endoscopy using the mean of midpoint of all crossovers was 0.097 mg/kg (95% CI, 0.004-0.099 mg/kg). Using the probit regression analysis, the ED₅₀ and ED₉₅ of remimazolam for successful endoscopy was 0.097 mg/kg (95% CI, 0.004-0.099 mg/kg) and 0.107 mg/kg (95% CI, 0.103-0.336 mg/kg), respectively. No adverse events were observed throughout the study period.

CONCLUSIONS

This pilot study suggests that the ED₅₀ and ED₉₅ of remimazolam tosilate with adjuvant sufentanil for sedation in liver cirrhosis patients undergoing oesophagogastric varices screening endoscopy was 0.097 and 0.107 mg/kg, respectively.

ED50 and ED95 of Propofol Combined with Different Doses of Intravenous Lidocaine for First-Trimester Uterine Aspiration: A Prospective Dose-Finding Study Using Up-and-Down Sequential Allocation Method

Purpose

This study aimed to test the effect of different doses of intravenous lidocaine on the median effective dose (ED50) and 95% effective dose (ED95) of propofol-induction dose and identify the optimal dose.

Patients and Methods

Patients undergoing first-trimester uterine aspiration were screened and randomly enrolled into the following groups: saline (L₀), 0.5 mg/kg lidocaine (L_0.5), 1.0 mg/kg lidocaine (L_1.0), and 1.5 mg/kg lidocaine (L_1.5). Anesthesia was induced with 1.0 µg/kg fentanyl. Prepared lidocaine or saline solution was injected later according to allocation, followed by propofol. The dose of propofol for each patient was determined using the up-and-down sequential study design. The primary end point was the ED50 and ED95 of the propofol-induction dose. The total propofol doses, awakening time, and adverse events were recorded.

Results

The ED50 (95% confidence interval) of propofol was significantly lower in groups L_1.0 and L_1.5 than group L₀ (1.6 [1.5–1.7] mg/kg and 1.8 [1.6–1.9] mg/kg, versus 2.4 [2.3–2.5] mg/kg, respectively; p<0.001). There was no significant difference in ED50 between groups L_1.0 and L_1.5 (p>0.05). However, surprisingly, the ED50 was significantly higher in group L_0.5 than L₀ (2.8 [2.6–3.0] mg/kg vs 2.4 [2.3–2.5] mg/kg; p<0.05). The total doses of propofol in groups L_1.0 and L_1.5 were lower than those in groups L₀ and L_0.5 (p<0.05). The systolic blood pressure (SBP) decline after anesthesia induction in group L_0.5 was greater than that in group L₀ (p<0.01). The incidence of respiratory depression in group L_0.5 was greater than that in groups L₀ and L_1.0 (p<0.05).

Conclusion

In patients who underwent first-trimester uterine aspiration, intravenous lidocaine 1.0 mg/kg prior to propofol injection significantly reduced the ED50 of propofol induction dose without severe side effects, equivalent to the effect of 1.5 mg/kg dose. We recommend 1.0 mg/kg as the optimal dose.

The Options for Neuraxial Drug Administration

Neuraxial drug administration, i.e., the injection of drugs into the epidural or intrathecal space to produce anesthesia or analgesia, is a technique developed more than 120 years ago. Today, it still is widely used in daily practice in anesthesiology and in acute and chronic pain therapy. A multitude of different drugs have been introduced for neuraxial injection, only a part of which have obtained official approval for that indication. A broad understanding of the pharmacology of those agents is essential to the clinician to utilize them in a safe and efficient manner. In the present narrative review, we summarize current knowledge on neuraxial anatomy relevant to clinical practice, including pediatric anatomy. Then, we delineate the general pharmacology of neuraxial drug administration, with particular attention to specific aspects of epidural and intrathecal pharmacokinetics and pharmacodynamics. Furthermore, we describe the most common clinical indications for neuraxial drug administration, including the perioperative setting, obstetrics, and chronic pain. Then, we discuss possible neurotoxic effects of neuraxial drugs, and moreover, we detail the specific properties of the most commonly used neuraxial drugs that are relevant to clinicians who employ epidural or intrathecal drug administration, in order to ensure adequate treatment and patient safety in these techniques. Finally, we give a brief overview on new developments in neuraxial drug therapy.