Effects of ciprofol for the induction of general anesthesia in patients scheduled for elective surgery compared to propofol: a phase 3, multicenter, randomized, double-blind, comparative study

OBJECTIVE

Ciprofol is a newly developed intravenous sedative-hypnotic drug. The objective of the study was to prove whether ciprofol was non-inferior to propofol for the successful induction of general anesthesia. The ideal post-induction sedation level was assessed by comparing patients' clinical symptoms and their hemodynamic effects in responding to noxious stimuli, mostly tracheal intubation and bispectral index (BIS) alterations following ciprofol/propofol administration.

PATIENTS AND METHODS

In this multi-center, randomized, double-blind phase 3 trial, selective surgery patients were randomly assigned in a 1:1 ratio to either ciprofol 0.4 mg/kg (n = 88) or propofol 2.0 mg/kg (n = 88) groups. The primary endpoint was the percentage of patients with successful anesthesia inductions. Secondary endpoints included the times to successful induction of general anesthesia and loss of the eyelash reflex, changes in BIS, as well as safety indicators.

RESULTS

The anesthesia induction success rates for both ciprofol 0.4 mg/kg and propofol 2 mg/kg groups were 100.0%, with a 95% CI lower success limit of -4.18% difference between the two groups, indicating that ciprofol was non-inferior to propofol. For secondary outcomes, the average time to successful anesthesia and loss of the eyelash reflex were 0.91 min and 0.80 min for ciprofol and 0.80 min and 0.71 min for propofol, respectively. The pattern of BIS changes with ciprofol was similar to propofol and stable during the anesthesia maintenance period. Safety was comparable with 88.6% TEAEs in the ciprofol group compared to 95.5% in the propofol group. The incidence of injection pain was significantly lower in the ciprofol group compared to the propofol group (6.8% vs. 20.5%, p < 0.05). In addition, the patients treated with ciprofol had a lesser increase in blood pressure and heart rate, and fewer cases with BIS > 60 within 15 min of intravenous administration, which indicated that ciprofol may provide a better ideal sedation level during the post-induction period under an equivalent dosing regimen to propofol.

CONCLUSIONS

Ciprofol for patients undergoing selective surgery is a new option for the induction of general anesthesia.

GABAergic excitotoxicity injury of the immature hippocampal pyramidal neurons' exposure to isoflurane

BACKGROUND

Certain anesthetics exhibit neurotoxicity in the brains of immature but not mature animals. γ-Aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, is excitatory on immature neurons via its action at the GABAA receptor, depolarizing the membrane potential and inducing a cytosolic Ca2+ increase ([Ca2+]i), because of a reversed transmembrane chloride gradient. Recent experimental data from several rodent studies have demonstrated that exposure to isoflurane during an initial phase causes neuronal excitotoxicity and apoptosis. GABAA receptor-mediated synaptic voltage-dependent calcium channels' (VDCCs) overactivation and Ca2+ influx are involved in these neural changes.

METHODS

We monitored [Ca2+]i using Fluo-4 AM fluorescence imaging. Using whole-cell patch clamp techniques, IVDCC (voltage-dependent calcium channel currents) were recorded from primary cultures of rat hippocampal neurons (5-day culture) exposed to isoflurane. To further investigate the neurotoxicity of high cytosolic-free calcium after isoflurane in a dose- and time-dependent manner, the possibility of increased caspase-3 levels was evaluated by Western blot and quantitative real-time polymerase chain reaction. Statistical significance was assessed using the Student t test or 1-way analysis of variance followed by the Tukey post hoc test.

RESULTS

Under control conditions, isoflurane enhanced the GABA-induced [Ca2+]i increase in a dose-dependent manner. Dantrolene and nicardipine markedly inhibited this enhancement mediated by isoflurane. Moreover, in Ca2+-free media, pretreatment with isoflurane did not show any influence on the caffeine-induced increase of [Ca2+]i. Similarly, using whole-cell recording, isoflurane increased the peak amplitude of IVDCC in the cultured neurons from rat hippocampus by depolarization pulses. Isoflurane (0.25, 0.5, 0.75, and 1 minimum alveolar concentration [MAC]) potentiated IVDCC peak current amplitude by 109.11%±9.03%, 120.56%±11.46%, 141.33%±13.87%, and 146.78%±15.87%, respectively. To analyze variation in protein levels, the effect of treatments with isoflurane on caspase-3 activity was dose- and time-dependent, reaching a maximal caspase-3 activity after exposure to 1 MAC for 6 hours (P<0.001). However, in the mRNA levels, hippocampal caspase-3 mRNA levels began to be significantly increased in isoflurane-treated developing rat hippocampal neurons after 6 hours of exposure to 0.25 MAC isoflurane (P<0.001).

CONCLUSIONS

Isoflurane-mediated enhancement of GABA-triggered [Ca2+]i release results from membrane depolarization with subsequent activation of VDCCs and further Ca2+-induced Ca2+ release from the ryanodine-sensitizing Ca2+ store. An increase in [Ca2+]i, caused by activation of the GABAA receptor and opening of VDCCs, is necessary for isoflurane-induced calcium overload of immature rat hippocampal neurons, which may be involved in the mechanism of an isoflurane-induced neurotoxic effect in the developing rodent brain.

Isoflurane enhances spontaneous Ca(2+) oscillations in developing rat hippocampal neurons in vitro

BACKGROUND

During the nervous system development, spontaneous synchronized Ca(2+) oscillations are thought to possess integrative properties because their amplitude and frequency can influence the patterning of neuronal connection, neuronal differentiation, axon outgrowth, and long-distance wiring. Accumulating studies have confirmed that some drugs such as volatile anesthetic isoflurane produced histopathologic changes in the central nervous system in juvenile animal models. Because the hippocampus plays an important role in learning and memory, the present work was designed to characterize the Ca(2+) oscillations regulated by volatile anesthetic isoflurane in primary cultures of developing hippocampal neurons (5-day-cultured).

METHODS

Primary cultures of rat hippocampal neurons (5-day-cultured) were loaded with the Ca(2+) indicator Fluo-4AM (4 microM) and were studied with a confocal laser microscope.

RESULTS

Approximately 22% of 5-day-cultured hippocampal neurons exhibited typical Ca(2+) oscillations. These oscillations were dose-dependently enhanced by isoflurane (EC50 0.5 MAC, minimum alveolar concentration) and this effect could be reverted by bicuculline (50 microM), a specific gamma-aminobutyric acid (GABA(A)) receptor antagonist.

CONCLUSION

Unlike its depressant effect on the Ca(2+) oscillations in adult neurons in previous researches, isoflurane dose-dependently enhanced calcium oscillations in developing hippocampal neurons by activating GABA(A) receptors, a major excitatory receptor in synergy with N-methyl-d-aspartate receptors at the early stages of development. It may be involved in the mechanism of an isoflurane-induced neurotoxic effect in the developing rodent brain.

[Patient-controlled analgesia with lornoxicam in patients undergoing gynecological surgery]

OBJECTIVE

To assess the analgesic effect and side effects of PCA with lornoxicam compared with morphine and tramadol.

METHODS

89 patients, scheduled for elective hysterectomy or hysteromyomectomy, were randomly divided into Group L, Group M and Group T. Three drugs administered i.v. via a patient-controlled analgesia for up to 24 h postoperatively.

RESULTS

Efficacy was assessed by comparing total pain relief (TOTPAR) and sum of pain intensity difference (SPID) over 24 h. Statistically significant equivalence of lornoxicam, morphine and tramadol was shown by TOTPAR values 15.2 +/- 3.9, 16.4 +/- 3.5 and 15.9 +/- 4.4, by SPID values 10.3 +/- 3.1, 9.0 +/- 2.0 and 9.2 +/- 4.7, respectively (P > 0.05). Lornoxicam caused fewer adverse events than morphine and tramadol (10.0%, 26.7% and 17.2% of patients, respectively).

CONCLUSION

The study suggests that lornoxicam provides an alternative to morphine or tramadaol for the treatment of postoperative pain.

[Ondansetron on postoperative nausea and vomiting]

The efficacy and safety of prophylactic intravenous ondansetron on prevention of postoperative nausea and vomiting were investigated in 65 ASA grades I-III patients undergoing elective abdominal surgery and receiving general anesthesia. Patients received ondansetron 4mg i.v. prior to a standardized technique for induction and intubation. Anesthesia was maintained with N2O-O2 and enflurane. The results showed that, by ondansetron 4mg, nausea and emesis could be significantly decreased. The effect lasted around 24h postoperatively without sedation. No one developed vomiting and only 9 patients developed nausea. No changes on laboratory parameters as well as vital signs were observed. No side-effects related to ondansetron were found. In prophylaxis of postoperative nausea and vomiting, ondansetron is effective and safe.