Prevention of Oxygen Desaturation in a Patient With Previous Experience of Severe Hypoxia in Modified Electroconvulsive Therapy by Transnasal Humidified Rapid-Insufflation Ventilator Exchange: A Case Report.

Transnasal humidified rapid-insufflation ventilator exchange (THRIVE) has been reported to have better efficacy during anesthesia induction compared to conventional mask ventilation, including improved oxygenation and prolonged safe apnea time. This study reports on the effectiveness of the THRIVE system during modified electroconvulsive therapy (mECT) for a patient experiencing severe hypoxia. A 78-year-old female patient with bipolar disorder received maintenance mECT every four weeks. She previously experienced a significant hypoxic event, with oxygen saturation (SpO2) dropping to 50% following electrical stimulation. In response, we employed the THRIVE system, designed to deliver high-flow, 100% oxygen, thereby extending apnea tolerance. The implementation of THRIVE ensured a stable oxygen supply, maintaining oxygen saturation levels above 95% throughout the mECT procedure. THRIVE is useful for treating hypoxia that occurs due to the unavoidable lack of ventilation during mECT.

Anesthetic management with remimazolam for a patient with hereditary angioedema:a case report.

BACKGROUND: Hereditary angioedema (HAE), a genetic disorder caused by C1-inhibitor deficiency or dysfunction, may cause mucosal edema in the upper airway during tracheal intubation and extubation. CASE REPORT: A 57-year-old man with HAE and a history of laryngeal edema, scheduled to undergo cervical laminoplasty under general anesthesia. General anesthesia was induced by continuous injection of remimazolam and remifentanil, during which manual mask ventilation and intubation were performed without difficulty. The patient was extubated under deep anesthesia. After emergence from general anesthesia, he had no significant upper airway edema and was treated with a C1-inhibitor seven hours post-surgery because of slight tongue swelling. No additional airway edema was observed, and the patient was discharged from the intensive care unit the following day. CONCLUSIONS: Deep anesthesia tracheal extubation with remimazolam may be effective in preventing upper airway edema during anesthetic management in patients with HAE. J. Med. Invest. 71 : 184-186, February, 2024.

Reply to Su et al. Comment on "Matsumoto et al. Remimazolam's Effects on Postoperative Nausea and Vomiting Are Similar to Those of Propofol after Laparoscopic Gynecological Surgery: A Randomized Controlled Trial. J. Clin. Med. 2023, 12, 5402".

We thank the authors for their insightful and thoughtful commentary on our recent publication [...].

Remimazolam-based anesthesia with flumazenil allows faster emergence than propofol-based anesthesia in older patients undergoing spinal surgery: A randomized controlled trial.

BACKGROUND: Remimazolam is a novel, ultrashort-acting benzodiazepine that can be antagonized by flumazenil. This study aimed to determine whether remimazolam-based anesthesia with flumazenil provides a more rapid emergence than propofol-based anesthesia in older patients undergoing spinal surgery. METHODS: This was a prospective, single-blind, randomized controlled trial. Forty-four patients > 75 years old who had undergone spinal surgery were enrolled in this study. They were randomly assigned to the remimazolam or propofol group (1:1) using a computer randomization system stratified by age and body weight. For anesthesia induction and maintenance, remifentanil was administered at a defined dose in both groups, and remimazolam or propofol was adjusted to maintain the bispectral index or state entropy monitoring within 40-60. All anesthetics were discontinued simultaneously after the postoperative X-ray and 0.5 mg flumazenil was administered to the remimazolam group. The primary outcome was extubation time after discontinuing anesthesia, and the secondary outcomes were time to eye opening, obeying commands, and achieving a white fast-track score (WFTS) of 12. RESULTS: Thirty-nine patients were finally analyzed: remimazolam group (n = 20), propofol group (n = 19). There were no significant differences in intraoperative variables, such as operative time, anesthesia time, and patient background, between the 2 groups. Extubation times were significantly shorter in the remimazolam group than in the propofol group (4 vs 8 minutes, P < .001). The time to eye opening, obeying commands, and achieving a WFTS of 12 were significantly shorter in the remimazolam group (P < .001, for all comparisons). CONCLUSION: Remimazolam-based anesthesia with flumazenil resulted in a faster emergence than propofol-based anesthesia in older patients undergoing spinal surgery.

Remimazolam's Effects on Postoperative Nausea and Vomiting Are Similar to Those of Propofol after Laparoscopic Gynecological Surgery: A Randomized Controlled Trial.

(1) Background: Remimazolam is a novel benzodiazepine that prevents postoperative nausea and vomiting (PONV), is more effective than volatile anesthetics, and was recently approved for use in Japan. (2) Methods: This prospective, double-blind, randomized controlled trial study aimed to compare the efficacy of remimazolam and propofol as general anesthetics in terms of the incidence of PONV after laparoscopic gynecological surgery (UMIN000046237). High-risk female patients who underwent general anesthesia with either remimazolam or propofol for the maintenance of anesthesia were enrolled. The primary outcome was the incidence of PONV in the two groups (i.e., REM versus PROP) 2 h and 24 h after surgery. The incidence of vomiting without nausea, rescue antiemetic use, and the severity of nausea were also evaluated. (3) Results: No significant differences in PONV were identified between the REM and PROP groups at 2 h or 24 h. Furthermore, no differences were observed in any of the measured parameters, and no adverse events were reported. (4) Conclusions: The results of the present study suggest that remimazolam may be as effective as propofol in preventing PONV; however, further investigation is necessary to identify possible differences between these two agents.

Rapid Dantrolene Administration with Body Temperature Monitoring Is Associated with Decreased Mortality in Japanese Malignant Hyperthermia Events.

Purpose: Malignant hyperthermia (MH) is a rare genetic disorder but one of the most severe complications of general anesthesia. The mortality rate of MH has dropped from 70% in the 1960s to 15% because of dantrolene, the only currently accepted specific treatment for MH. In this study, we retrospectively identified the optimal dantrolene administration conditions to reduce MH mortality further. Methods: Our database performed a retrospective analysis of patients with MH clinical grading scale (CGS) grade 5 (very likely) or 6 (almost certain) between 1995 and 2020. We examined whether dantrolene administration affected mortality and compared the clinical variables associated with improved prognosis. Furthermore, a multivariable logistic regression analysis was used to identify specific variables associated with improved prognosis. Results: 128 patients met the inclusion criteria. 115 patients were administered dantrolene; 104 survived, and 11 died. The mortality rate of patients who were not administered dantrolene was 30.8%, which was significantly higher than those of patients who were administered dantrolene (P = 0.047). Among patients administered dantrolene, the interval from the first sign of MH to the start of dantrolene administration was significantly longer in the deceased than in the survivors (100 min vs. 45.0 min, P < 0.001), and the temperature at the start of dantrolene administration was also significantly higher in the deceased (41.6°C vs. 39.1°C, P < 0.001). There was no significant difference in the rate of increase in temperature between the two, but there was a substantial difference in the maximum temperature (P < 0.001). The multivariable analysis also showed that the patient's temperature at dantrolene administration and interval from the first MH sign to dantrolene administration was significantly associated with improved prognosis. Conclusions: Dantrolene should be given as rapidly as possible once MH has been diagnosed. Beginning treatment at a more normal body temperature can prevent critical elevations associated with a worse prognosis.

Remimazolam Requires Less Vasopressor Support during Induction and Maintenance of General Anesthesia in Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement: A Retrospective Analysis from a Single Center.

Introduction: We compared the hemodynamics during general anesthesia with remimazolam and conventional anesthetics in patients with severe aortic stenosis (AS). Methods: This was a retrospective single-center analysis. We reviewed the records of 42 patients who underwent transcatheter aortic valve implantation with a transfemoral artery approach under general anesthesia from January to December 2020. Patients were divided into three groups based on the general anesthetic used for (induction/maintenance) remimazolam/remimazolam (Group R/R), propofol/sevoflurane (Group P/S), and midazolam/propofol (Group M/P). Vasopressor use (ephedrine, phenylephrine, and noradrenaline) was compared among the groups. Results: The number of patients in each group was 15 (Group R/R), 13 (Group P/S), and 14 (Group M/P), with no significant difference in background characteristics and intraoperative vital signs. For anesthesia induction, doses of ephedrine and phenylephrine used were significantly lower in Group R/R (ephedrine [mg]: Group R/R 2 [0-4] vs. Group P/S 8 [8-12], P < 0.001, Group R/R vs. Group M/P 5 [0-15], P = 0.39; phenylephrine (mg): Group R/R 0 [0-0.08] vs. Group P/S 0.15 [0.10-0.20], P = 0.03, Group M/P 0.21 [0.04-0.40], P = 0.08). For anesthesia maintenance, the noradrenaline dose used was low in the Group R/R (noradrenaline [µg/kg/min]: Group R/R 0.019 [0.015-0.039], Group P/S 0.042 [0.035-0.045], P = 0.02, Group M/P 0.048 [0.040-0.059], P < 0.01). Conclusion: In patients with severe AS, induction and maintenance of anesthesia with remimazolam resulted in less overall vasopressor use than conventional general anesthetics.

Intravenous patient-controlled analgesia does not increase the risk of postoperative delirium compared to patient-controlled epidural analgesia: a propensity score-matched retrospective cohort study.

BACKGROUND: It is unclear whether the doses of opioids and the routes of administration used for postoperative analgesic management are associated with delirium. We aimed to compare the incidence of postoperative delirium (POD) between intravenous patient-controlled analgesia (IVPCA) and patient-controlled epidural analgesia (PCEA) in patients who underwent postoperative analgesic management using opioids. METHODS: We retrospectively investigated surgical patients (n=3,324) who received patient-controlled analgesia (PCA). Morphine was used for IVPCA, and fentanyl and ropivacaine were used for PCEA. The patients' background characteristics, perioperative management, presence of POD, and postoperative analgesia technique after IVPCA (n=1,184) or PCEA (n=2,140) were assessed. We divided the patients into IVPCA and PCEA groups and compared the incidence of POD by propensity score matching. We used the independent t-test for comparisons between the groups, and P<0.05 as considered as statistically significant. RESULTS: POD was noted in a total of 125 patients (3.8%); 55 patients (4.6%) with IVPCA and 70 patients (3.3%) with PCEA (P=0.046). There was no statistically significant difference in cumulative opioid usage up to postoperative day 2 (in mg) between patients with and without POD (POD 62.7±39.8 vs. non-POD 48.9±50.3, P=0.10). After propensity score matching, 1,156 patients with similar baseline characteristics were selected. POD was noted in 22 of 578 patients (3.8%) in the IVPCA group and 30 of 578 patients (5.2%) in the PCEA group, with no difference between the two groups (P=0.256). On the other hand, opioid usage was higher in the IVPCA group than in the PCEA group (P<0.001). CONCLUSIONS: There was no difference in the incidence of POD between morphine IVPCA and fentanyl PCEA when the patient characteristics were matched using propensity score matching. POD occurs regardless of the route and dose of opioid administration.

Relationship Between the Loaded Pressure and Flow Rate of Packed Red Blood Cells and Various Infusion Solutions in Normal Infusion Lines and Catheters.

BACKGROUND: We investigated the relationship between the loaded pressure and flow rate in various catheters and the entire infusion line including the catheters, in several infusion solutions and packed red blood cells. METHODS: We connected the infusion line and catheter to the infusion solution and used an outer pressure bag or a compressor to pressurize the infusion solution bag to a pressure within the clinical (up to 450 mm Hg) or higher range (up to 1050 mm Hg). We approximated the relationship between the loaded pressure and flow rate in the entire infusion line including the catheter, versus the catheter alone, as a power function and compared the power numbers. RESULTS: In the clinical pressure range of normal saline, the power numbers of the entire infusion line for the 24-, 22-, 20-, and 18-gauge catheters were 0.76, 0.82, 0.81, and 0.86, respectively, while those for the catheter alone were 0.67, 0.63, 0.56, and 0.44, respectively. In the higher pressure range of normal saline, the power numbers of the entire infusion line for the 24-, 22-, 20-, and 18-gauge catheters were 0.68, 0.70, 0.71, and 0.73, respectively, while those for the catheter alone were 0.62, 0.61, 0.59, and 0.58, respectively. As the power number of the entire infusion line was closer to 1.00 than the values of the catheter, the relation between the loaded pressure and the flow rate was more linear in the entire infusion line than that in the catheter. Similar results were obtained using packed red blood cells and 40% glycerin mixture in normal saline. CONCLUSIONS: Regardless of the type of infusion solution or transfusion, the pressure-flow relationship in the catheter was nonlinear and not directly proportional. However, within the clinical pressure range (up to 450 mm Hg), the relationship between the flow rate and pressure in the entire infusion line was almost linear and proportional.

Acute-onset paraplegia as an unexpected complication under general anesthesia in supine position during abdominal endovascular aneurysm repair: a case report.

BACKGROUND: Acute onset paraplegia after endovascular aneurysm repair (EVAR) is a rare but well-known complication. We here show a 79-year-old woman with paraplegia caused by static and dynamic spinal cord insult not by ischemia after EVAR. CASE PRESENTATION: The patient underwent EVAR for abdominal aortic aneurism under general anesthesia in the supine position. She had a medical history of lumbar canal stenosis. After the surgery, we recognized severe paraplegia and sensory disorder of lower limbs. Although the possibility of spinal cord ischemia was considered at that time, postoperative magnetic resonance imaging (MRI) revealed burst fracture of vertebra and compressed spinal cord. CONCLUSIONS: Patients with spinal canal stenosis can cause extrinsic spinal cord injury even with weak external forces. Thus, even after EVAR, it is important to consider extrinsic factors as the cause of paraplegia.

Effects of Remimazolam and Propofol on Ca2+ Regulation by Ryanodine Receptor 1 with Malignant Hyperthermia Mutation.

BACKGROUND: We investigated the potential safety of remimazolam and propofol in malignant hyperthermia- (HM-) susceptible patients using ryanodine receptor 1- (RYR1-) expressing human embryonic kidney- (HEK-) 293 cells. METHODS: We compared the enhanced responsiveness of HEK-293 cells expressing wild-type RYR1 with that of mutant RYR1 to caffeine following perfusion with remimazolam or propofol. Furthermore, we investigated whether RYR1 enhanced the responsiveness of cells to remimazolam or propofol and compared the median effective concentration (EC50; i.e., the concentration required to reach half-maximal activation) using an unpaired two-tailed t-test while a P < 0.05 was considered significant. RESULTS: Remimazolam and propofol did not promote the caffeine-induced increase in intracellular Ca2+ levels in HEK-293 cells expressing mutant RYR1 even with exposure to approximately 100-fold the clinically used concentration. In wild-type RYR1, EC50 values of remimazolam following refusion vs. nonperfusion were 2.86 mM vs. 2.75 mM (P = 0.76) while for propofol perfusion vs. nonperfusion, they were 2.76 mM vs. 2.75 mM, respectively (P = 0.83). In mutant RYR1, EC50 values of remimazolam refusion vs. nonperfusion were 1.58 mM vs. 1.71 mM, respectively (P = 0.63) while for propofol perfusion vs. nonperfusion, they were 1.65 mM vs. 1.71 mM, respectively (P = 0.73). Remimazolam and propofol increased intracellular Ca2+ levels in a concentration-dependent manner, but the effect was not enhanced by RYR1. EC50 values of remimazolam with non-RYR1 vs. wild-type RYR1 were 1.00 mM vs. 0.92 mM, respectively (P = 0.91) while those of propofol were 1.09 mM vs. 1.05 mM, respectively (P = 0.84). CONCLUSIONS: The increase in intracellular Ca2+ concentration caused by remimazolam or propofol was not considered an RYR1-mediated reaction. We conclude that remimazolam and propofol can be safely used as an anesthetic in MH-susceptible patients with RYR1-mutation without causing MH and may be safely substituted for an MH-triggering anesthetic when RYR1-mediated MH occurs.

Intraoperative responses of motor evoked potentials to the novel intravenous anesthetic remimazolam during spine surgery: a report of two cases.

BACKGROUND: Remimazolam is a novel short-acting benzodiazepine characterized by metabolism independent from organ function. We report intraoperative MEP responses of two patients who underwent spine surgery under general anesthesia using remimazolam. CASE PRESENTATION: In case 1, MEP monitoring was successfully performed with the use of a fixed dose of remimazolam at 0.5 mg/kg/h and remifentanil at 0.2 µg/kg/min. In case 2, an increasing dose of remimazolam from 0.5 to 1.5 mg/kg/h during the operation did not affect MEP signals. In both cases, remimazolam was titrated to maintain the values of entropy electroencephalogram (EEG) monitoring at 40-60. CONCLUSIONS: General anesthesia using remimazolam and remifentanil can be a valuable alternative for spine surgery with MEP monitoring by EEG to assess the optimal dose.

Rocuronium-sugammadex use for electroconvulsive therapy in a hemodialysis patient: a case report.

BACKGROUND: Recently, rocuronium with subsequent use of sugammadex was proposed for electroconvulsive therapy (ECT) as an alternative to succinylcholine. Because sugammadex is cleared via the kidney with no metabolism, it is unknown that rocuronium-sugammadex use is safe in hemodialysis patients who received ECT. CASE PRESENTATION: In this case report, we used rocuronium with subsequent administration of sugammadex in a 69-year-old female, hemodialysis patient, scheduled for ten ECT sessions for severe major depression. In the initial eight sessions, we tested the feasibility of rocuronium-sugammadex use for ECT. During the series of four ECT sessions, we measured plasma concentrations for the sum of sugammadex and sugammadex-rocuronium complex and observed whether possible residual sugammadex affected muscle relaxation during subsequent sessions of ECT. The results showed the feasibility of rocuronium-sugammadex use as muscle relaxants for ECT in patients undergoing hemodialysis. However, an accumulation of sugammadex did occur even after two sessions of hemodialysis, and residual sugammadex decreased the effect of the rocuronium given in the subsequent ECT sessions. Rocuronium-sugammadex was successfully utilized as muscle relaxants for ECT in this patient. CONCLUSIONS: Our experience in this case may indicate that if succinylcholine is contraindicated, rocuronium-sugammadex can be an alternative method for muscle relaxation during ECT in patients undergoing hemodialysis. When this rocuronium-sugammadex procedure is used, the effect of residual sugammadex after hemodialysis on the subsequently administered rocuronium should be considered.