Enflurane requirement for blocking adrenergic responses to incision in infants and children

Effects of different plasma target concentrations of remifentanil on the MACBAR of sevoflurane in children with laparoscopic surgery

Background

To investigate the effects of different plasma target concentrations of remifentanil on the minimum alveolar concentration (MAC) for blocking adrenergic response (BAR) of sevoflurane in children with laparoscopic herniorrhaphy.

Methods

Seventy-five children with 3-7 years old scheduled for laparoscopic herniorrhaphy were randomly divided into group R₀, group R_1, and group R₂ according to different remifentanil plasma target concentration (0, 1, and 2 ngml^-1), respectively. The MAC_BAR of sevoflurane was determined by the up-and-down and sequential method in each group. The concentrations of epinephrine and noradrenaline were also determined at corresponding time points.

Results

A total of 52 child patients were used among the anticipated 75 patients. In groups R₀, R_1, and R₂, the MAC_BAR of sevoflurane was (3.29 ± 0.17) %, (2.12 ± 0.10) % and (1.29 ± 0.11) %, respectively, and a significant difference was found among the three groups (P<0.05). The changes of epinephrine and noradrenaline concentrations in each group before and after insufflation of carbon dioxide pneumoperitoneum showed no significant differences.

Conclusion

Remifentanil by target-controlled infusion can effectively reduce the MAC_BAR of sevoflurane during laparoscopic surgery in children. At a similar effect of MAC_BAR, both the changes of epinephrine and noradrenaline concentrations are not affected by the infusion of different remifentanil target concentrations.

Trial registration

The trial was registered at http://www.chictr.org.cn(ChiCTR1800019393, 8, Nov, 2018).

Effects of different remifentanil target concentrations on MACBAR of sevoflurane in patients with liver dysfunction under carbon dioxide pneumoperitoneum stimulus: A randomized controlled trial

WHAT IS KNOWN AND OBJECTIVE

Remifentanil can effectively decrease the sevoflurane concentration to block sympathetic adrenergic response to CO₂ pneumoperitoneum stimulus,and liver dysfunction will significantly reduce the MAC_BAR (minimum alveolar concentration for blocking adrenergic response) of sevoflurane. However, the effects of different remifentanil concentrations on the MAC_BAR of sevoflurane in patients with liver dysfunction are unclear. The aim of this study was to observe the effects of different remifentanil concentrations by intravenous target-controlled infusion on the MAC_BAR of sevoflurane in patients with grade B liver dysfunction under carbon dioxide pneumoperitoneum stimulus.

METHODS

Seventy-five patients with grade B liver dysfunction undergoing elective laparoscopic surgery were selected, and randomly divided into three groups with remifentanil plasma target concentrations of 0 (group R₀ ), 1 (group R₁ ) and 2 (group R₂ ) ng/ml. Anaesthesia was induced by intravenous injection of propofol 2-3 mg/kg, remifentanil 2 μg/kg and cisatracurium 0.15 mg/kg. All groups were inhaled different concentrations of sevoflurane. The determination of sevoflurane MAC_BAR in each group was used a method of sequential-allocation technique, and venous blood samples were taken before and after the creation of carbon dioxide pneumoperitoneum to determine plasma adrenaline and noradrenaline concentrations.

RESULTS AND DISCUSSIONS

The MAC_BAR of sevoflurane in groups R₀ , R₁ and R₂ was 4.83%, 3.00% and 2.10%, respectively. The MAC_BAR of sevoflurane was significantly difference among the three groups. When a similar effect of MAC_BAR had achieved in each group, no significant differences were found in the changes of plasma adrenaline and noradrenaline concentrations before and after the creation of pneumoperitoneum. What is new and conclusion Target-controlled infusion of different concentrations of remifentanil can reduce sevoflurane MAC_BAR during pneumoperitoneum stimulation in patients with liver dysfunction in some degree. However, the changes of plasma adrenaline and noradrenaline concentrations are consistent in the three groups when patient's stress response was inhibited at the same degree.