Remimazolam-based total intravenous anesthesia in a patient with a confirmed diagnosis of malignant hyperthermia: a case report.

BACKGROUND: Malignant hyperthermia (MH) is a rare, life-threatening disorder of calcium homeostasis in skeletal muscle cells that is triggered by volatile anesthetics and succinylcholine, leading to a hypermetabolic reaction. The pathogenic ryanodine receptor 1 (RYR1) gene variant is critical. Patients susceptible to MH should avoid triggering agents, and total intravenous anesthesia (TIVA) is preferred. Remimazolam is safe in patients with suspected MH. CASE PRESENTATION: We present the first case of remimazolam treatment in a genetically confirmed patient with MH without MH development. A 72-year-old man with a family history of MH underwent remimazolam-based TIVA. After informed consent was obtained, a muscle biopsy and genetic testing were performed. Intraoperatively and postoperatively, the patient exhibited no signs of MH. An enhanced function of the RYR1 channel into releasing calcium was indicated, and the genetic testing revealed a pathogenic variant of RYR1. CONCLUSIONS: Remimazolam-based TIVA is safe in patients confirming the diagnosis of MH.

Effects of intravenous injection of indocyanine green on the oxygen reserve index (ORi™).

PURPOSE: The oxygen reserve index (ORi™) is a parameter used for the noninvasive evaluation of arterial partial pressure of oxygen (PaO2), specifically in the 100-200 mmHg range. We aimed to report on the impact of indocyanine green (ICG) on the ORi™. METHODS: In this study, we retrospectively examined patients who underwent neurosurgery between April and July 2019 and assessed the impact of ICG on ORi™. We excluded patients who did not use ICG or who were not examined for ORi™. The dose and timing of ICG administration were determined by a neurosurgeon. The changes in ORi™ were measured for up to 30 min. RESULTS: We analyzed ten patients and found that the ORi™ increased to 1.00 in all of them. The median time for ORi ™ to rise to 1.00 after ICG administration was 2 min (range 1-4). After rising to 1.00, ORi ™ decreased and took 27 min to return to the pre-dose value. CONCLUSION: It is important to consider the initial rapid increase and subsequent slow decrease in ORi™ when using ICG during surgery.

[Effect of dexmedetomidine on intraoperative somatosensory evoked potential monitoring].

BACKGROUND: Intraoperative somatosensory-evoked potential (SEP) monitoring has become a part of neurosurgical procedures. In this study, we evaluated the effect of dexmedetomidine on SEP monitoring during neurosurgical anesthesia. METHODS: Eight patients scheduled for neurosurgery were studied. Anesthesia was maintained with continuous infusion of propofol at 2 microg x ml(-1) concentration using target controlled infusion (TCI). A loading dose of dexmedetomidine was infused at 6 microg x kg(-1) hr(-1) for 10 min and SEP was recorded. Infusion of dexmedetomidine was continued at 0.5 microg x kg(-1) x min(-1) for 10 min and SEP was recorded. We measured the change of amplitude and latency of SEP (N20-P25) and compared to baseline values. RESULTS: There was no statistically significant change in the cortical SEP amplitude (98.0 +/- 18.1% after a loading dose of dexmedetomidine and 112.7 +/- 16.8% at 0.5 microg x kg(-1) x min(-1) of dexmedetomidine, respectively) or latency (101.5 +/- 1.7% after a loading dose of dexmedetomidine and 101.9 +/- 1.7% at 0.5 microg x kg(-1) x min(-1) of dexmedetomidine, respectively). Mean blood pressure rose from 81 mmHg to 95 mmHg after initiation of dexmedetomidine infusion. Heart rate did not change. CONCLUSIONS: These findings suggest that dexmedetomidine has possibilities to produce an ideal environment as an anesthetic adjunct in patients requiring intrapoerative SEP monitoring.

[Use of AirWay Scope for tracheal intubation in bright sunlight].

BACKGROUND: The AirWay Scope (AWS), which is equipped with a wide-angle LCD monitor, has been developed to achieve accurate and safe tracheal intubation under various conditions, including emergency settings. However, since bright sunlight degrades the image quality of LCDs, we investigated its usefulness outdoors in bright sunlight. METHODS: A single anesthesiologist intubated a mannequin with an AWS and conventional direct laryngoscope indoors and in sunlight outdoors, using 6 trials for each condition. Success rate, Cormack grade, and intubation time from device insertion to removal were recorded. RESULTS: Indoors, all tracheal intubations with both devices achieved Cormack grade 1 and were successful. Outdoors, all the laryngoscopes achieved Cormack grade 1 and intubation was successful, whereas intubation with the AWS was successful in 3 trials, while 2 esophageal intubations and 1 failure also occurred. In addition, sunlight deteriorated the image quality of the LCD and Cormack grade could not be determined. The intubation times for the AWS and laryngoscope indoors were 8.7+/-1.8 and 17.0+/-6.5 sec, and outdoors were 18.7+/-9.0 and 21.3+/-4.9 sec, respectively. CONCLUSIONS: Our findings indicate that successful tracheal intubation with an AWS is difficult to achieve in bright sunlight.