Intrathecal dexmedetomidine as an adjuvant to plain ropivacaine for spinal anesthesia during cesarean section: a prospective, double-blinded, randomized trial for ED50 determination using an up-down sequential allocation method.

BACKGROUND: Intrathecal dexmedetomidine, as an adjuvant to local anesthetics, has been reported to improve the quality of spinal anesthesia and reduce the required local anesthetic dose. However, the optimal dosage regimen for intrathecal dexmedetomidine combined with plain ropivacaine for cesarean section (CS) remains undetermined. The present study aimed to determine the median effective dose (ED50) of intrathecal dexmedetomidine as an adjuvant to plain ropivacaine for spinal anesthesia during CS. METHODS: Sixty parturients undergoing CS were randomly assigned to either group: plain ropivacaine 8 mg (Group Rop8) or plain ropivacaine 10 mg (Group Rop10). The initial dosage of intrathecal dexmedetomidine in each group was 5 µg. The effective dose was defined as a bilateral sensory block at the level of T6 or above to pinprick attained within 10 min after intrathecal injection, without the need for supplementary intraoperative epidural anesthesia. Effective or ineffective responses were determined, followed by a 1 µg increment or decrement in the dose of intrathecal dexmedetomidine for the next parturient using up-down sequential allocation. ED50 were calculated using probit regression. RESULTS: The ED50 of intrathecal dexmedetomidine with plain ropivacaine was 5.9 µg (95% confidence interval [CI], 4.9-7.4 µg) in Group Rop8 and 3.1 µg (95% CI, 0.1-4.8 µg) in Group Rop10 (P < 0.05). Hemodynamic stability, side effects, patient satisfaction and neonatal outcomes were comparable between the two groups. CONCLUSIONS: The present data suggested that the ED50 of intrathecal dexmedetomidine as an adjuvant to 8 mg and 10 mg plain ropivacaine in spinal anesthesia during cesarean section was approximately 6 µg and 3 µg, respectively. TRIAL REGISTRATION: Chinese Clinical Trial Registry, identifier: ChiCTR2200055928.

Effects of Thoracic Paravertebral Block on Postoperative Analgesia in Infants and Small Children undergoing Ultra-Fast Track Cardiac Anesthesia: A Randomized Controlled Trial.

OBJECTIVES: To assess whether a preoperative bilateral thoracic paravertebral block (TPVB) would improve postoperative analgesia in infants and small children undergoing open cardiac surgery in the protocol of an ultra-fast track cardiac anesthesia (UFTCA). DESIGN: A single-center, prospective, randomized, controlled study. SETTING: At a tertiary children's medical center. PARTICIPANTS: A total of 180 children undergoing cardiac surgery, aged 1 month to 3 years. INTERVENTIONS: Patients are allocated randomly to TPVB and parent- and/or nurse-controlled intravenous analgesia (PNCA) group (Group T) or PNCA group (Group P). MEASUREMENTS AND MAIN RESULTS: The primary outcome is the postoperative pain scores. The secondary outcome are intraoperative consumption of sufentanil, time to extubation, using of neostigmine, cumulative total and invalid PCA attempts in 24 and 48 hours after surgery, hospitalization characteristics, perioperative blood glucose, postoperative arterial oxygen partial pressure, arterial carbon dioxide partial pressure (PaCO2) and brain natriuretic peptide (BNP). The postoperative pain scores within 24 hours, intraoperative consumption of sufentanil, total, and invalid PCA attempts in 24 and 48 hours, perioperative blood glucose and BNP on the seventh day in Group T were all significantly lower than those in Group P (p < 0.001). The time to extubation, the use of neostigmine, and PaCO2 on the sixth hour, postoperatively, were significantly smaller in Group T than those in Group P (p < 0.05). There were no significant differences in the hospitalizations between the 2 groups. CONCLUSIONS: A combination of bilateral single dose TPVB and PNCA pain management is superior to a PNCA pain management alone in infants and small children undergoing open cardiac surgery and contributes to a rapid recovery with preferable perioperative outcomes in the protocol of UFTCA.

The effect of ultra-fast track cardiac anaesthesia in infants and toddlers: a randomised trial.

BACKGROUND: The usefulness of ultra-fast track cardiac anaesthesia may give great benefits to patients; however, its usefulness has not been completely evaluated in infants and toddlers, who are generally considered the most difficult group for ultra-fast track cardiac anaesthesia. METHOD: A total of 130 children were allocated randomly into to a ultra-fast track cardiac anaesthesia group (Group D) or a conventional anaesthesia group (Group C) (each n = 65). In Group D, dexmedetomidine was administrated at a dosage of 1 µg/kg/hour after induction. The patient- controlled intravenous analgesia was dexmedetomidine and sufentanil. In Group C, patients were infused with of the same volume of normal saline, and sufentanil alone for patient-controlled intravenous analgesia. The dosages of sufentanil, extubation time, haemodynamic parameters, postoperative hospitalisation conditions, pain and sedation scores, blood gas analysis, and inotropic scores were all recorded. RESULTS: The dosage of sufentanil (1.49 ± 0.05 vs. 3.81 ± 0.04 µg, p < 0.001) and extubation time (2.63 ± 0.52 vs. 436.60 ± 22.19 minutes, p < 0.001) in Group D were all significantly lower than those in Group C. Moreover, cardiac intensive care unit stay time, total hospital stay, hospitalisation costs, postoperative lactate levels, and inotropic scores were also significantly lower in Group D. CONCLUSIONS: Using of ultra-fast track cardiac anaesthesia in infants and toddlers is effective, it not only reduce the perioperative requirement for opioids and shorten the extubation time but also decreases the inotrope requirement and provide a better postoperative condition for young children.

The kinin B1 receptor mediates alloknesis in a murine model of inflammation.

Noxious stimuli and non-noxious mechanical stimuli elicit itch (alloknesis) instead of pain on skin lesions of patients with atopic dermatitis. We previously found that bradykinin evokes an itch-related scratching response through activation of kinin B1 receptor in skin inflamed using complete Freund's adjuvant. In this study we investigated whether alloknesis is evoked in CFA-inflamed skin and the involvement of kinin receptors. In our results, alloknesis was elicited four days after CFA-inflammation. Furthermore, pretreatment with a B1 receptor antagonist or µ-opioid receptor antagonist significantly reduced alloknesis. In contrast, treatment with a B2 receptor antagonist significantly increased alloknesis. These results suggest that the alloknesis response is mediated by the activation of kinin B1 receptor but antagonized by the B2 receptor in CFA-inflamed mice.