Remifentanil stabilizes hemodynamics with modulating subthalamic beta oscillation during deep brain stimulation

General anesthesia is a promising method for advanced Parkinson's disease patients unable to tolerate awake deep brain stimulation (DBS) surgery. However, anesthetic agents must be kept at relatively low levels to preserve the quality of intraoperative microelectrode recordings, which can lead to unstable hemodynamic conditions. Remifentanil, with its sedative and analgesic properties, could offer a solution. This study retrospectively analyzed microelectrode recordings of the subthamic nucleus (STN) and hemodynamic responses in patients with Parkinson's disease who received deep brain stimulation surgery under controlled volatile anesthesia with/without remifentanil infusion. From October 2017 to June 2019, 24 patients with Parkinson's disease who received bilateral subthalamic deep brain stimulation surgery in Hualien Tzu Chi Hospital with (n = 12) or without remifentanil infusion (n = 12) were enrolled in this study. We conducted a comprehensive spike analysis, examining frequency, inter-spike interval properties, modified burst index, modified pause index, and modified pause ratio. Additionally, we performed spike frequency spectrum analysis to investigate oscillatory activity in high-frequency, multi-unit, and single-unit neuronal activity. Our findings revealed no differences in STN firing characteristics, while a significant decrease in high beta power was observed in multi-unit activity in the remifentanil group. Notably, nine patients in the non-remifentanil group required additional nicardipine, whereas none in the remifentanil group did. Conclusively, for patients with advanced Parkinson's disease sensitive to external stimulation at low minimum alveolar concentration, remifentanil co-administration is an option to avoid unstable hemodynamic conditions during subthalamic deep brain stimulation surgery.

Effects of Transverse Abdominis Plane (TAP) Block on the MACBAR of Sevoflurane in Gynecologic Patients with Laparoscopic Pneumoperitoneal Stimulation: An Up-Down Sequential Allocation Study

Purpose

This study aimed to observe the effect of bilateral transverse abdominis plane (TAP) block on the MACBAR of sevoflurane in gynecological patients with laparoscopic pneumoperitoneal stimulation.

Patients and Methods

Fifty patients who underwent laparoscopic surgery were randomly assigned to either the control group (n= 25) or the TAP block group (n= 25). Patients in the TAP block group were subjected to a bilateral transversal abdominal muscle plane block with 0.33% ropivacaine (20 mL on each side) guided by ultrasound. The control group received an equal volume of normal saline. The MACBAR of sevoflurane in each group was determined using a sequential allocation technique.

Results

The MACBAR of sevoflurane in the TAP block group was significantly lower than that in the control group (4.20% [95% confidence interval {CI}, 4.02%-4.38%] vs 5.03% [95% CI, 4.89%-5.18%]).

Conclusion

Bilateral TAP block can reduce the MACBAR of sevoflurane in gynecological patients with pneumoperitoneum stimulation.

Trial Registration Number

ChiCTR2100046517. The trial is publicly available and registered at www.chictr.org.cn on May 18, 2021.

ED50 and ED95 of Remimazolam Tosilate Combined with Different Doses of Fentanyl in Elderly Patients for Painless Gastroscopy

Background

The novel short-acting benzodiazepine drug, remimazolam tosilate, has been employed for sedation during endoscopic procedures. The optimal loading dosage of remimazolam tosilate in gastroscopy for elderly patients when co-administered with fentanyl remains unclear. Therefore, the primary objective of our research was to ascertain the median effective dose (ED50) and the 95% effective dose (ED95) of remimazolam tosilate in combination with various fentanyl dosages for elderly patients undergoing painless gastroscopy.

Methods

Seventy-five patients aged ≥65 years and American Society of Anesthesiologists (ASA) class I-III were recruited to undergo elective painless gastroscopy. All patients were randomized assigned to group F1, group F2, and group F3, and were injected intravenously with different doses of fentanyl (0.5 ug/kg, 1 ug/kg, and 1.5 ug/kg) 3 minutes prior to the administration of remimazolam tosilate, respectively. The initial preset dose of remimazolam tosilate was 0.3 mg/kg in group F1, 0.2 mg/kg in group F2, 0.15 mg/kg in group F3. The dose gradient was 0.02 mg/kg per group according to the up-and-down sequential method. Probibt regression model was employed to determine the ED50 and ED95 of remimazolam tosilate.

Results

The ED50 of remimazolam tosilate in group F3 was lower than that in group F1 and F2 (0.095 [0.088-0.108] mg/kg vs 0.162 [0.153-0.171] mg/kg; 0.258 [0.249-0.266] mg/kg, p < 0.05). The ED95 of remimazolam tosilate was 0.272 mg/kg (95% CI: 0.264-0.295 mg/kg) in group F1, 0.175 mg/kg (95% CI: 0.167-0.200 mg/kg) in group F2 and 0.109 mg/kg (95% CI: 0.101-0.135 mg/kg) in group F3. The total dosage of remimazolam tosilate decreased gradually with the increasing of fentanyl (p < 0.001). The frequency of injection pain was higher in group F1 compared to groups F2 and F3 (p < 0.05). The patients in group F3 had a lower incidence of hypotension than in groups F1 and F2 (p < 0.05). There was no respiratory depression, intraoperative consciousness, dizziness or delirium in the three groups.

Conclusion

The concurrent use of fentanyl reduces the dosage of remimazolam tosilate required for sedative gastroscopy in elderly patients in a dose-dependent manner. Moreover, 1.5 ug/kg fentanyl combined with remimazolam tosilate may reduce the incidence of hypotension and injection pain. These findings should be confirmed in a large-scale study.

Effects of Etco2 on the Minimum Alveolar Concentration of Sevoflurane that Blunts the Adrenergic Response to Surgical Incision: A Prospective, Randomized, Double-Blinded Trial

BACKGROUND

CO2 has anesthetic potency and effectively influences the circulatory system. We investigated the effects of Etco2 on the minimum alveolar concentration of sevoflurane that blunts the adrenergic response to surgical incision (MAC-BAR) in patients undergoing radical surgery for gastric carcinoma.

METHODS

Ninety patients undergoing radical gastric-carcinoma surgery under general anesthesia were enrolled and randomly assigned into 3 groups. After intubation, the Etco2 in group L (n = 30), group N (n = 30), and group H (n = 30) was adjusted to 25 mm Hg ≤ Etco2 <30 mm Hg, 30 mm Hg ≤ Etco2 < 40 mm Hg, and 40 mm Hg ≤ Etco2 < 45 mm Hg, respectively, by changes in controlled ventilation. Hemodynamics and depth of anesthesia were observed before and after skin incision. The MAC-BAR of sevoflurane for each group was determined using an up-and-down sequential-allocation technique.

RESULTS

To obtain 7 crossovers, 25, 26, and 26 patients were used in group L, group N, and group H, respectively. The MAC-BAR of sevoflurane using the up-and-down method for group H was significantly lower than that for group L (2.3% [95% confidence interval {CI}, 2.2-2.4] vs 2.9% [95% CI, 2.7-3.0]; difference, -0.6% [95% CI, -0.7 to -0.4], P < .001) and group N (2.3% [95% CI, 2.2-2.4] vs 2.8% [95% CI, 2.8-2.9]; difference, -0.5% [95% CI, -0.7 to -0.4], P < .001), while no significant difference was found between group L and group N (P = 1.000).

CONCLUSIONS

Higher Etco2 levels (Etco2 values equal to 40 mm Hg or higher) can effectively decrease the MAC-BAR of sevoflurane in patients undergoing radical surgery for gastric carcinoma.

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.

Postoperative recovery of patients with differential requirements for sevoflurane after abdominal surgery: A prospective observational clinical study

An association between animals and volatile anaesthetic requirements has been shown; however, evidence related to the postoperative outcome of human patients is lacking. Our aim was to investigate whether there is a difference in the requirement for sevoflurane among people undergoing gastrointestinal surgery.We observed 390 adult patients who underwent gastrointestinal surgery with an American Society of Anesthesiologists physical status of I or II with an expected surgery duration of > 2 hours. We used the bispectral index (BIS) to guide the regulation of end-tidal sevoflurane concentration (ETsevo). The mean ETsevo from 20 minutes after endotracheal intubation to 2 hours after the start of surgery was calculated for all patients. Differential sevoflurane requirements were identified according to ETsevo. The BIS, ETsevo, heart rate, mean arterial pressure, dose of sufentanil and cisatracurium, tracheal extubation time, incidence of intraoperative awareness, and incidence of postoperative nausea and vomiting were compared between patients with a low requirement for sevoflurane (group L) and patients with a high requirement for sevoflurane (group H).The mean ETsevo of the 390 patients was 1.55% ± 0.26%. Based on our definition, patients with an ETsevo of < 1.29% were allocated to the low requirement group (group L; n = 69), while patients with an ETsevo of > 1.81% were allocated to the high requirement group (group H; n = 78). The ETsevo of group L was significantly lower than the ETsevo of group H (1.29% ± 0.014% vs 1.82% ± 0.017%, P < .001). There was no significant difference in the ETsevo, BIS, heart rate, mean arterial pressure, dose of sufentanil and cisatracurium, tracheal extubation time, incidence of intraoperative awareness, and incidence of postoperative nausea and vomiting. The tracheal extubation time in the L group was significantly shorter than that in the H group. No intraoperative awareness occurred.There was a significant difference in the requirement for sevoflurane in adult patients. The tracheal extubation time in group L was significantly shorter than that in group H.

Laparoscopic distal gastrectomy and hyperthermic intraperitoneal chemotherapy in the treatment of advanced gastric cancer: a retrospective case-matched study on perioperative outcomes

Background

This study aimed to assess the safety and efficacy of laparoscopic distal gastrectomy (LDG) with intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC) for advanced gastric cancer (AGC).

Methods

In this case-matched study, we retrospectively reviewed the database of 223 patients with AGC who underwent LDG in Tangdu Hospital from April 2016 to February 2019. Among all participants, 177 patients underwent LDG alone and 46 underwent LDG with HIPEC. We matched total of 138 (1:2) patients from the LDG + HIPEC group (n 46) and the LDG group (n 92) for gender, age, date of operation, and tumor-node-metastasis (TNM) stage of tumor.

Results

There was no significant difference in the Clavien-Dindo classification of complications between LDG alone and LDG + HIPEC patients. Further analysis showed the morbidity of gastroparesis to be significantly increased in LDG + HIPEC patients. At the same time, we found that the operation time, the time to 1st flatus, and hospital stay were longer in LDG + HIPEC patients and the incidence of abdominal recurrence 2 years after operation was significantly higher in the LDG group than the LDG + HIPEC group.

Conclusions

The combination of LDG with intraoperative HIPEC is a safe and feasible method for AGC and HIPEC will limit the recovery of gastrointestinal functions. In addition, during the follow-up of our study, although there was no statistical difference between the two groups in abdominal recurrence at 2 years after surgery, a decreasing trend of abdominal recurrence in LDG + HIPEC patients could be seen in comparison to LDG patients.

Effect of low-dose ketamine on MACBAR of sevoflurane in laparoscopic cholecystectomy: A randomized controlled trial

WHAT IS KNOWN AND OBJECTIVE

Low-dose ketamine can reduce the minimum alveolar concentration of sevoflurane necessary to block the adrenergic response (MAC_BAR ) in animals. However, the effects of low-dose ketamine on the sevoflurane MAC_BAR in patients undergoing laparoscopic surgery are unclear. The aim of this study was to investigate the effects of three different low doses of ketamine on the MAC_BAR of sevoflurane in patients undergoing laparoscopic cholecystectomy.

METHODS

One hundred patients who underwent laparoscopic cholecystectomy were enrolled. After general anaesthesia induction and tracheal intubation, patients received sevoflurane anaesthesia in combination with a loading dose of saline followed by infusion or a loading dose of 0.5 mg/kg ketamine followed by a continuous infusion of 5 (K₁ group), 10 (K₂ group) and 20 μg/kg/min (K₃ group). The target concentration of end-tidal sevoflurane was maintained for at least 20 minutes before carbon dioxide pneumoperitoneum stimulus. The MAC_BAR of sevoflurane in each group was determined by using an up-and-down sequential allocation technique.

RESULTS AND DISCUSSION

Seventy-one patients completed the study. The values of MAC_BAR for sevoflurane were 5.3% in the K₀ , 4.8% in K₁ , 3.3% in K₂ and 3.2% in K₃ groups. The use of ketamine significantly reduced the MAC_BAR of sevoflurane compared to sevoflurane alone. The K₂ and K₃ groups showed significantly lower values of MAC_BAR than that in the K₁ group. However, a higher dose of ketamine in the K₃ group did not further reduce the sevoflurane MAC_BAR . The mean arterial blood pressure (MAP) values before pneumoperitoneum in the K₂ and the K₃ groups were significantly higher compared to those in the K₀ and K₁ groups. Compared with the values before pneumoperitoneum, the heart rate and MAP after pneumoperitoneum were significantly increased. Overall, the haemodynamics remained stable during the study period in all groups.

WHAT IS NEW AND CONCLUSION

A loading dose of 0.5 mg/kg ketamine followed by a continuous infusion of 10.0 μg/kg/min led to a significant decrease in the MAC_BAR of sevoflurane in patients undergoing laparoscopic cholecystectomy.

Effects of different sufentanil target concentrations on the MACBAR of sevoflurane in patients with carbon dioxide pneumoperitoneum stimulus

BACKGROUND

This study aims to observe the effects of different target controlled plasma sufentanil concentrations on the minimum alveolar concentration (MAC) of sevoflurane for blocking adrenergic response (BAR) in patients undergoing laparoscopic cholecystectomy with carbon dioxide pneumoperitoneum stimulation.

METHODS

Eighty-five patients undergoing laparoscopic cholecystectomy, aged 30-65 years, with American Society of Anesthesiologists physical status I-II, were enrolled in this study. All the patients were randomly divided into 5 groups (S₀, S₁, S₂, S₃, S₄) with different sufentanil plasma target concentration (0.0, 0.1, 0.3, 0.5, 0.7 ng ml^- 1). Anesthesia was induced by inhalation of 8% sevoflurane in 100% oxygen, and 0.6 mg kg^- 1 of rocuronium was intravenously injected to facilitate the insertion of a laryngeal mask airway. The end-tidal sevoflurane concentration and sufentanil plasma target concentration were adjusted according to respective preset value in each group. The hemodynamic response to pneumoperitoneum stimulus was observed after the end-tidal sevoflurane concentration had been maintained stable at least for 15 min. The MAC_BAR of sevoflurane was measured by a sequential method. Meanwhile, epinephrine (E) and norepinephrine (NE) concentrations in the blood were also determined before and after pneumoperitoneum stimulus in each group.

RESULTS

When the method of independent paired reversals was used, the MAC_BAR of sevoflurane in groups S₀, S₁, S₂, S₃, S₄ was 5.333% (confidence interval [CI] 95%: 5.197-5.469%), 4.533% (95% CI: 4.451-4.616%), 2.861% (95% CI: 2.752-2.981%), 2.233% (95% CI: 2.142-2.324%) and 2.139% (95% CI: 2.057-2.219%), respectively. Meanwhile, when the isotonic regression analysis was used, the MAC_BAR of sevoflurane in groups S₀, S₁, S₂, S₃, S₄ was 5.329% (95% CI: 5.321-5.343%), 4.557% (95% CI: 4.552-4.568%), 2.900% (95% CI: 2.894-2.911%), 2.216% (95% CI: 2.173-2.223%) and 2.171% (95% CI: 2.165-2.183%), respectively. The MAC_BAR was not significantly different between groups S₃ and S₄ when using 0.5 and 0.7 ng ml^- 1 of sufentanil plasma target concentrations. No significant difference was found in the change of E or NE concentration between before and after pneumoperitoneum stimulation in each group.

CONCLUSIONS

The MAC_BAR of sevoflurane can be decreased with increasing sufentanil plasma target concentrations. A ceiling effect of the decrease occurred at a sufentanil plasma target concentration of 0.5 ng ml^- 1. When the sympathetic adrenergic response was inhibited in half of the patients to pneumoperitoneum stimulation in each group, the changes of E and NE concentrations showed no significant differences.

TRIAL REGISTRATION

The study was registered at http://www.chictr.org.cn ( ChiCTR1800015819 , 23, April, 2018).

Effect of sex differences in remifentanil requirements for inhibiting the response to a CO2 pneumoperitoneum during propofol anesthesia: an up-and-down sequential allocation trial

Background

A CO₂ pneumoperitoneum during a laparoscopic procedure causes violent hemodynamic changes. However, the remifentanil required to inhibit the cardiovascular response to a CO₂ pneumoperitoneum combined with propofol remains unknown. Moreover, the sex of the patient may influence the response to opioids, which can affect this requirement. The main objective of this study was to compare the required median effective concentration (EC₅₀) of remifentanil for inhibiting the cardiovascular response to a CO₂ pneumoperitoneum between female and male patients during propofol anesthesia.

Methods

The current study is an up-and-down sequential allocation trial. Forty-six patients with American Society of Anesthesiologists physical status I or II, a body mass index 18 to 30 kg/m², aged 20 to 60 years, and scheduled for laparoscopic surgery were enrolled. Induction of anesthesia was performed by target-controlled infusion. The effective effect-site concentration (Ce) of propofol was 4 μg/ml. The Ce of remifentanil was initially 4 ng/ml and then adjusted to a predetermined level after I-gel laryngeal mask airway insertion. The Ce of remifentanil for each patient was determined by the response of the previous patient using the modified Dixon “up-and-down” method. The first patient received remifentanil at 5.0 ng/ml Ce, and the step size between patients was 0.5 ng/ml.

Results

Patients characteristics including age, body mass index, American Society of Anesthesiologists physical status, type of surgery and surgery duration, were comparable between male and female patients. The EC₅₀ of remifentanil required to inhibit the response to a CO₂ pneumoperitoneum based on the Dixon “up-and-down” method in women (4.17 ± 0.38 ng/ml) was significantly lower than that in men (5.00 ± 0.52 ng/ml) during propofol anesthesia (P = 0.01).

Conclusions

The EC₅₀ of remifentanil required to inhibit the response to a CO₂ pneumoperitoneum was lower in women than in men during propofol anesthesia.

Trial registration

The study was registered at http://www.chictr.org.cn (ChiCTR-IOR-17011906, 8th, July, 2017).

Increased minimum alveolar concentration-awake of Sevoflurane in women of breast surgery with sleep disorders

BACKGROUND

Sleep disorders are commonly encountered in clinic. Evidences showed that sleep deprivation may modulate the effectiveness of general anesthetics in rats. However, this phenomenon has not been explored in humans. The study aimed to investigate whether the hypnotic potency of sevoflurane in patients with sleep disorders differ from patients with normal sleep habits.

METHODS

We recruited 44 patients scheduled for elective breast surgery and eventually analyzed 38 patients, including 19 subjects with normal sleep habits and 19 subjects with sleep disorders. According to the Dixon 'up-and-down' design, patients received sevoflurane at preselected concentrations starting at 1.0 vol%. After a steady-state period, a verbal command for testing awakening was performed. Based on the negative or positive response to the verbal command, we decreased or increased the concentration of sevoflurane by 0.2 vol% in the next patient accordingly. Plasma orexin-A was also measured before observation.

RESULTS

The MACawake of sevoflurane was 0.80% [95% confidence interval (CI), 0.683-0.926%] in the sleep disordered group vs 0.60% [95% CI, 0.493-0.689%] in the control group. The relative median potency between groups was 0.750 (95% CI, 0.236-0.969). Patients with sleep disorders had significantly higher orexin-A levels than control (72.17 ± 18.24 vs. 36.16 ± 14.18 pg/mL). A significant, positive relationship was detected between orexin-A level and probability of awakening (OR = 1.081, 95% CI is 1.020-1.146, P = 0.008).

CONCLUSIONS

MACawake of sevoflurane is higher in mild-aged women of breast surgery with sleep disorders compared to those with normal sleep habits. The increased anesthetic requirement may be related to changes of orexin-A levels. These findings suggest that sleep may have a potential impact on clinical anesthesia, including changes of sensitivity to anesthetics or postoperative complications. Further research is needed to confirm this hypothesis.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR1800016022), date of registration 07 May 2018.

Phosphatidylinositol 3-kinase inhibition induces vasodilator effect of sevoflurane via reduction of Rho kinase activity

AIMS

This study was aimed to examine whether a volatile anesthetic sevoflurane in clinical doses reduces vasoconstriction under the inhibition of phosphatidylinositol 3-kinase (PI3K) in the rat and human arteries and whether the intravenous administration of the PI3K inhibitor decreases blood pressure in rats under the sevoflurane inhalation.

MATERIALS AND METHODS

Rat arteries (n=5-6) and human omental arteries (n=5-6) were subjected to isometric force recordings and western immunoblotting for Rho kinase, mitogen-activated protein kinase, and protein kinase C. Some arteries were incubated with sevoflurane (1.5% or 3%), a selective PI3K inhibitor LY294002 (3×10^-6mol/L) or the combination. Mean arterial pressure (MAP) and heart rate (HR) in rats (n=7) were evaluated with or without intravenous injection of LY294002 (3×10^-6mol/L) under 2% sevoflurane inhalation.

KEY FINDINGS

Sevoflurane with LY294002, but not sevoflurane or LY294002 solely, inhibited the phenylephrine-induced contraction (32% to 52% decrease at phenylephrine [3×10^-6mol/L] in rat arteries and [3×10^-5mol/L] in human arteries). Sevoflurane (3%) only with LY294002 decreased Rho kinase activity in the rat aorta into 30%. Intravenous LY294002 reduced MAP (8.1-12.4mmHg decrease), but not HR, in rats under 2% sevoflurane inhalation.

SIGNIFICANCE

Clinical sevoflurane doses with PI3K inhibition reduce the contraction of rat and human arteries ex vivo resulting from Rho kinase inhibition, and systemic blood pressure of rats in vivo. These results suggest that sevoflurane potentially causes vasodilation and hypotension in patients receiving anti-cancer therapy that inhibits PI3K.