Radial artery catheterization using a novel T-type ultrasound probe: a single-center randomized study.

Ultrasound guidance has been reported to facilitate radial artery catheterization compared with the palpation method. However, a recent meta-analysis showed that there was not significant differences in the first attempt success rate between the long-axis in-plane (LA-IP) method and the short-axis out-of-plane method. In 2023, we started using a novel T-type probe. We can recognize the needle first during the radial artery access with the short-axis view and then dose it with the long-axis view using the T-type probe. Therefore, we hypothesized that the T-type probe-guided method might heighten the first attempt success rate in radial artery catheterization, even for non-expert practitioners, compared with the LA-IP technique. One hundred and fifty adult patients, older than 20 years, ASA I to III, were randomly assigned to the T-type probe-guided group (Group T: n = 75) or the LA-IP group (Group L: n = 75). The primary outcome was the first attempt success rate. The first attempt success rate in Group T (49/71, 69%) was significantly higher than that in Group L (31/68, 46%) (p = 0.0062). The present study showed that the T-type probe might facilitate the radial artery catheterization rather than the LA-IP method.

Differences in circulating blood volume changes during emergence from general anesthesia in transcatheter aortic valve implantation and MitraClip implantation.

PURPOSE: We aimed to compare changes in the circulating blood volume (CBV) during emergence from general anesthesia in patients undergoing transcatheter aortic valve implantation (TAVI) and MitraClip implantation. METHOD: We included 97 patients who underwent TAVI or MitraClip implantation. The primary outcome was the rate of change in the estimated CBV associated with emergence from general anesthesia. The secondary outcomes were hemoglobin and hematocrit values before and after emergence from anesthesia for each procedure. Additionally, the independent factors associated with changes in the estimated CBV were assessed using multiple regression analysis. RESULTS: In the TAVI group, the hemoglobin concentration increased from 9.6 g/dL before emergence from anesthesia to 10.8 g/dL after emergence (P < 0.001; mean difference, 1.2 g/dL, 95% confidence interval [CI] 1.1-1.3 g/dL). Conversely, no statistically significant change was observed in the hemoglobin concentration before and after emergence from anesthesia in the MitraClip group. The mean rate of change in the estimated CBV was - 15.4% (standard deviation [SD] 6.4%) in the TAVI group and - 2.4% (SD, 4.7%) in the MitraClip group, indicating a significant decrease in the estimated CBV in the former than in the latter (P < 0.001; mean difference, 13.0%; 95% CI 9.9-16.1%). CONCLUSION: Emergence from general anesthesia increased the hemoglobin concentration and decreased the estimated CBV in patients undergoing TAVI but did not elicit significant changes in patients undergoing MitraClip implantation. These results may provide a rationale for minimizing blood transfusions during general anesthesia in patients undergoing these procedures.

INJEX50 could improve the success rate of local anesthesia for arterial cannulation in the pediatric intensive care unit: A randomized, double-blind, single-center study.

BACKGROUND: Quick arterial cannulation is required in pediatric emergency situation, which require effective local anesthesia to avoid withdrawal movement. However, pediatric local anesthesia could be difficult because of withdrawal movement. Jet injectors, which are needleless and provide local anesthesia quickly, could be helpful for pediatric local anesthesia during arterial cannulation. AIMS: This study aimed to examine whether new jet injector "INJEX50" could improve the success rate of local anesthesia for arterial cannulation in pediatric intensive care unit compared with the current standard of care, infiltration using a 26-gauge needle. METHODS: This study was a randomized, double-blind, single-center study. Participants were infants and young children in the pediatric intensive care unit, who required an arterial line. Local anesthesia was performed with either a 26-gauge needle (group C) or INJEX50 (group I) before arterial cannulation. The primary outcome (success of local anesthesia) was the presence of withdrawal movement at the time of skin puncture for arterial cannulation. The secondary outcomes included rescue sedation during arterial cannulation. Data were analyzed using Fisher's exact test and the Mann-Whitney U-test, with values of p < .05 considered statistically significant. RESULTS: Seventy patients were randomly assigned to groups C and I. The local anesthesia success rate in group I (30/35 [86%]) was significantly higher than that in group C (15/35 [43%], odds ratio, 8.00; 95% confidence interval, 2.51-25.5; p = .0005). In conclusion, INJEX50 could improve success rate of local anesthesia for arterial cannulation in pediatric intensive care unit compared with 26-gauge needle.

Comparison of the negative effect of remimazolam and propofol on cardiac contractility: Analysis of a randomised parallel-group trial and a preclinical ex vivo study.

Remimazolam is a newly developed ultra-short-acting benzodiazepine that exerts sedative effects. This study aimed to clarify the effects of remimazolam on cardiac contractility. In a randomised-parallel group trial, haemodynamic parameters were compared between propofol (n = 11) and remimazolam (n = 12) groups during the induction of general anaesthesia in patients undergoing non-cardiac surgery. In a preclinical study, the direct effects of remimazolam on cardiac contractility were also evaluated using isolated rat hearts. RNA sequence data obtained from rat and human hearts were analysed to assess the expression patterns of the cardiac γ-aminobutyric acid type A (GABAA ) receptor subunits. In a clinical study, the proportional change of the maximum rate of arterial pressure rise was milder during the study period in the remimazolam group (propofol: -52.6 [10.2] (mean [standard deviation])% vs. remimazolam: -39.7% [10.5%], p = 0.007). In a preclinical study, remimazolam did not exert a negative effect on left ventricle developed pressure, whereas propofol did exert a negative effect after bolus administration of a high dose (propofol: -26.9% [3.5%] vs. remimazolam: -1.1 [6.9%], p < 0.001). Analysis of the RNA sequence revealed a lack of γ subunits, which are part of the major benzodiazepine binding site of the GABAA receptor, in rat and human hearts. These results indicate that remimazolam does not have a direct negative effect on cardiac contractility, which might contribute to its milder effect on cardiac contractility during the induction of general anaesthesia. The expression patterns of cardiac GABAA receptor subunits might be associated with the unique pharmacokinetics of benzodiazepines in the heart.

Comparing leak pressure of LMA® ProSeal™ versus i-gel® at head rotation: a randomized controlled trial.

PURPOSE: The effect of head rotation on supraglottic airway (SGA) oropharyngeal leak pressure (OPLP) has not been well elucidated. The aim of this study was to help clarify which SGA device provides higher OPLP at head-rotated position. METHODS: Patients who underwent elective surgery under general anesthesia were enrolled and randomly divided into laryngeal mask airway (LMA®) ProSeal™ and i-gel® groups. The allocated SGA device was inserted under anesthesia. The primary outcome was OPLP, and secondary outcomes were ventilation score, expiratory tidal volume, and maximum pressure under volume-controlled ventilation (VCV) with an inspiratory tidal volume of 10 mL·kg-1 ideal body weight and fibreoptic view of the vocal cords at 0°, 30°, and 60° head rotation. RESULTS: Data from 78 and 76 patients were analyzed in the LMA ProSeal and i-gel groups, respectively. The mean (standard deviation) OPLP of the LMA ProSeal was significantly higher than that of the i-gel at the 60° head-rotated position (LMA ProSeal, 20.4 [6.5] vs i-gel, 16.9 [7.8] cm H2O; difference in means, 3.6; adjusted 95% confidence interval, 0.5 to 6.6; adjusted P = 0.02, adjusted for six comparisons). The maximum pressure under VCV at 60° head rotation was significantly higher in the LMA ProSeal group than in the i-gel group. The expiratory tidal volume of the LMA ProSeal did not significantly change with head rotation and was significantly higher than that of the i-gel at 60° head rotation. Ventilation score, fibreoptic view of the vocal cords, and complications were not significantly different between the ProSeal and i-gel groups. CONCLUSIONS: The LMA ProSeal provides higher OPLP than the i-gel at a 60° head-rotated position under general anesthesia. TRIAL REGISTRATION: Japan Registry of Clinical Trials (https://jrct.niph.go.jp) (JRCT1012210043); registered 18 October 2021.

RéSUMé: OBJECTIF: L'effet de la rotation de la tête sur la pression de fuite oropharyngée (OPLP en anglais) des dispositifs supraglottiques (DSG) n'est pas encore bien élucidé. L'objectif de cette étude était d'aider à déterminer quel DSG procurait une pression de fuite oropharyngée plus élevée lorsque la tête est en rotation. MéTHODE: Les patient·es qui ont bénéficié d'une intervention chirurgicale non urgente sous anesthésie générale ont été recruté·es et aléatoirement réparti·es en deux groupes, soit masque laryngé (LMA®) ProSeal™ ou i-gel®. Le DSG alloué a été inséré sous anesthésie. Le critère d'évaluation principal était la pression de fuite oropharyngée, et les critères d'évaluation secondaires étaient le score de ventilation, le volume courant expiratoire et la pression maximale sous ventilation à volume contrôlé (VVC) avec un volume courant inspiratoire de 10 mL·kg−1 du poids corporel idéal et une visualisation fibroscopique des cordes vocales à une rotation de la tête de 0°, 30° et 60°. RéSULTATS: Les données de 78 et 76 patient·es ont été analysées dans les groupes LMA ProSeal et i-gel, respectivement. La pression de fuite oropharyngée moyenne (écart type) du LMA ProSeal était significativement plus élevée que celle de l'i-gel en position de rotation de la tête à 60° (LMA ProSeal, 20,4 [6,5] vs i-gel, 16,9 [7,8] cm H2O; différence de moyennes, 3,6; intervalle de confiance ajusté à 95 %, de 0,5 à 6,6; P = 0,02 ajusté, ajusté pour six comparaisons). La pression maximale sous VVC à une rotation de la tête de 60° était significativement plus élevée dans le groupe LMA ProSeal que dans le groupe i-gel. Le volume courant expiratoire du LMA ProSeal n'a pas changé de manière significative avec la rotation de la tête et était significativement plus élevé que celui de l'i-gel à une rotation de la tête de 60°. Le score de ventilation, la visualisation fibroscopique des cordes vocales et les complications n'étaient pas significativement différents entre les groupes ProSeal et i-gel. CONCLUSION: Le LMA ProSeal procure une pression de fuite oropharyngée plus élevée que l'i-gel dans une position de rotation de la tête à 60° sous anesthésie générale. ENREGISTREMENT DE L'éTUDE: Registre japonais des essais cliniques (https://jrct.niph.go.jp) (JRCT1012210043); enregistré le 18 octobre 2021.

I-gel Plus acts as a superior conduit for fiberoptic intubation than standard i-gel.

The supraglottic airway (SGA) is widely used. I-gel Plus is a next-generation i-gel with some improvements, including facilitation of fiberoptic tracheal intubation (FOI). To compare the performance of i-gel Plus and standard i-gel as conduits for FOI, a Thiel-embalmed cadaveric study was conducted. Twenty-two anesthesiologists were enrolled as operators in Experiment 1. The i-gel Plus and standard i-gel were inserted into one cadaver, and the FOI was performed through each SGA. The primary outcome was time required for FOI. The secondary outcomes were the number of attempts and visual analog scale (VAS) score for difficulty in FOI. Moreover, fiberoptic views of the vocal cords in each SGA were assessed by an attending anesthesiologist using nine cadavers in Experiment 2. The percentage of glottic opening (POGO) score without fiberscope tip upward flexion and upward angle of the fiberscope tip to obtain a 100% POGO score were evaluated as secondary outcomes. The time for FOI through i-gel Plus was significantly shorter than that through standard i-gel (median (IQR), i-gel Plus: 30.3 (25.4-39.0) s, vs standard i-gel: 54.7 (29.6-135.0) s; median of differences, 24.4 s; adjusted 95% confidence interval, 3.0-105.7; adjusted P = 0.040). Although the number of attempts for successful FOI was not significantly different, the VAS score for difficulty in the i-gel Plus group was significantly lower (easier) than that in the standard i-gel group. Moreover, i-gel Plus required a significantly smaller upward angle of the fiberscope tip to obtain a 100% POGO score. FOI can be performed more easily using i-gel Plus than using standard i-gel because of the improved fiberoptic visibility of vocal cords.

Effect of a Low Concentration of Sevoflurane Combined With Propofol on Transcranial Electrical Stimulation Motor Evoked Potential: A Case Series.

Transcranial electrical motor evoked potential (TCeMEP) is used to monitor the integrity of intraoperative motor function. Total intravenous anesthesia (TIVA) is the preferred method because its effect on MEP is relatively smaller than volatile anesthetics. However, maintaining the balanced anesthesia in long-time surgery using TIVA is challenging and may sometime cause problems including body movement during microsurgery. Such problems can be avoided by intraoperative anesthesia management using a mixture of propofol and a low concentration of sevoflurane. We recorded TCeMEP under a mixture of propofol and low concentration of sevoflurane anesthesia in three cases of neurosurgery. Anesthesia was induced with a 5.0 µg/mL target-controlled infusion of propofol and 0.6 mg/kg rocuronium. General anesthesia was maintained by propofol and 0.1-0.25 µg/kg/min remifentanil infusion. After the recording of control TCeMEP, sequential inhalation of 0.2 minimum alveolar concentration (MAC) and 0.5 MAC of sevoflurane was performed. The duration of each sevoflurane inhalation was 10 minutes, and the MACs were adjusted by the patient's age. In our cases, the combination of propofol and 0.2 MAC sevoflurane suppressed the amplitude of TCeMEP to 38.0±21.7% (379.8±212.0 µV), but the amplitude was high enough for evaluation of motor function monitoring. On the other hand, the combination of 0.5 MAC sevoflurane greatly decreased the amplitude of TCeMEP to 6.3±6.0% (71.9±66.9 µV) resulting in less than 150 µV, and it was difficult to record the change in TCeMEP amplitude over time. The combination of 0.2 MAC sevoflurane with TIVA might enable TCeMEP monitoring with TIVA.

A case of safe airway management by fiber-optic nasotracheal intubation in general anesthesia in a pediatric patient with Hajdu-Cheney syndrome: a case report.

BACKGROUND: Hajdu-Cheney syndrome (HCS) is an extremely rare disorder characterized by progressive acro-osteolysis. A unique facial structure and deformity of the cervical spine are associated with a difficult airway. Although several reports describe general anesthesia with orotracheal intubation for patients with HCS, there have been no reports of nasotracheal intubation with a risk of skull base fracture. We describe nasotracheal intubation for oral surgery in a patient with HCS. CASE PRESENTATION: A 13-year-old girl with HCS was scheduled for dental surgery. Preoperative computed tomography revealed no abnormalities including fractures in the skull base or cervical spine. After confirming a lack of vocal cord paralysis by bronchofiberscopic inspection from the nose, general anesthesia was induced with sevoflurane, remifentanil, and rocuronium. Fiber-optic nasotracheal intubation was successfully performed without complications such as depletion of oxygen saturation and massive epistaxis, and the surgery was completed uneventfully. She was discharged the day after surgery with no anesthesia-related complications. CONCLUSIONS: We were able to safely manage the airway of a patient with HCS by nasotracheal intubation under general anesthesia.

Head cooling wrap could suppress the elevation of core temperature after cardiac surgery during forced-air warming in a pediatric intensive care unit: a randomized clinical trial.

PURPOSE: The main aim of the current trial was to explore our hypothesis that cooling head wraps lower the core temperature more effectively than ice packs on the head during forced-air warming after pediatric cardiac surgeries. METHODS: This study was a single-center Randomized Controlled Trial. Participants were children with a weight ≤ 10 kg and hyperthermia during forced-air warming after cardiac surgeries. When the core temperature reached 37.5 °C, ice packs on the head (group C) or a cooling head wrap (group H) were used as cooling devices to decrease the core temperature. The primary outcome was the core temperature. The secondary outcomes were the foot surface temperature and heart rate. We measured all outcomes every 30 min for 240 min after the patient developed hyperthermia. We conducted two-way ANOVA as a pre-planned analysis and also the Bonferroni test as a post hoc analysis. RESULTS: Twenty patients were randomly assigned to groups C and H. The series of core temperatures in group H were significantly lower than those in group C (p < 0.0001), and post hoc analysis showed that there was no significant difference in core temperatures at T0 between the two groups and statistically significant differences in all core temperatures at T30-240 between the two groups. There was no difference between the two groups' surface temperatures and heart rates. CONCLUSIONS: Compared to ice packs on the head, head cooling wraps more effectively suppress core temperature elevation during forced-air warming after pediatric cardiac surgery.

Transcranial electrical stimulation technique for induction of unilateral motor evoked potentials.

OBJECTIVE: Transcranial electrical stimulation motor evoked potentials (TES-MEP) are widely used to monitor motor function; however, broad current spread and induced body movement are limitations of this technique. We herein report a localized stimulation technique for TES-MEP that induces unilateral MEP responses. METHODS: The stimulation of C1(+)-C4(-) or C2(+)-C3(-) was performed to induce right- or left-sided muscle contraction, respectively, in 70 patients. Electromyography was recorded by placing electrodes on the bilateral abductor pollicis brevis (APB) and abductor hallucis (AH) muscles. Stimulation conditions were regulated in the range to induce unilateral muscle contractions contralateral to the anodal stimulation. The thresholds and amplitudes of TES-MEP were retrospectively analyzed. RESULTS: The thresholds of APB were lower than those of AH in 47 patients, AH thresholds were lower than those of APB in 6 patients, and both APB and AH started to respond at the same intensity in 15 patients. This technical stimulation induced contralateral limb contractions with a suprathreshold stimulation of 129.4 ± 35.6 mA (mean ± standard deviation) in 68 patients (97%). Amplitudes in the suprathreshold stimulation of APB and AH responses were 727.5 ± 695.7 and 403.3 ± 325.7 µV, respectively. CONCLUSIONS: The C1(+)-C4/C2(+)-C3(-) stimulation in TES-MEP enables a localized stimulation to induce unilateral MEP responses. SIGNIFICANCE: Our stimulation technique enables the stable and safe monitoring of unilateral limbs, and contributes to the reliable monitoring of motor function in neurosurgery.

Mouth-Opener Technique for Ultrasound-Guided Inferior Alveolar Nerve Block: A Case Series of Extraction of Impacted Mandibular Third Molars.

Extraction of the impacted mandibular third molar (IMTM) is common in oral surgery, but its postoperative pain is severe. Ultrasound-guided inferior alveolar nerve block (UGIANB) is an analgesic technique in the mandibular nerve region. We describe UGIANB using a mouth opener and report the cases with a good postoperative course. Six patients underwent the extraction of bilateral IMTMs under general anesthesia. After surgery, we performed UGIANB and administered 5 mL of 0.375% levobupivacaine on each side. The postoperative numerical rating scale pain scores were 1 (0-2) and 2.5 (0-5) (mean (range)), postoperative day one and seven, respectively. The postoperative quality of recovery-40 scores were 188.5 (8.1) and 191.7 (7.6) (mean (SD)), postoperative day one and seven, respectively. No procedural complications were encountered. We performed UGIANB with a mouth opener on a patient with IMTM extraction and were able to provide safe and good analgesia.

A case of monosomy 21 presented with difficult tracheal intubation.

BACKGROUND: Monosomy 21 is a rare chromosomal abnormality. It is mainly associated with mental retardation, intellectual disability, growth retardation, microcephaly, and characteristic facial features. General anesthesia in adults with this disease has not been reported. We report difficult airway management of an adult patient with monosomy 21. CASE DESCRIPTION: A 30-year-old female was scheduled for laparoscopic gynecological surgery. She was diagnosed with monosomy 21 at birth and accompanied with mental retardation. Preoperative examination revealed limited mouth opening with Mallampati score of IV, but no abnormal laboratory test or chest X-P. Anesthesia was performed using general anesthesia with epidural analgesia. Although bag-mask ventilation was improved by a muscle relaxant, mouth opening was further restricted, and laryngoscope insertion was impossible. Tracheal intubation was achieved using a bronchofiberscope. The operation procedure was completed, and the patient was discharged from the hospital without any major postoperative complications. CONCLUSIONS: In this patient, mouth opening was further reduced after induction of general anesthesia with a muscle relaxant. Preoperative evaluation and adequate preparation of airway management are important for general anesthesia in an adult patient with monosomy 21.

Anesthetic management of tracheal stent extraction using a double gum elastic bougie technique.

BACKGROUND: Tracheal stenosis is a life-threatening condition, and management of a patient with a risk of tracheal stenosis is challenging for anesthesiologists. In this report, we describe a method for airway management using two gum elastic bougie method when removing a tracheal stent via a tracheostomy orifice with a risk of airway restenosis. CASE PRESENTATION: A 71-year-old man had an enlarged squamous cell carcinoma of the lung invading the upper mediastinum that had caused severe stenosis of the trachea. Two months after diagnosis, a tracheal stent had been placed to maintain tracheal patency. One month after stent placement, acute respiratory failure was induced by upper airway obstruction caused by subglottic airway edema due to mechanical stimulation of the cranial end of the stent, and the patient was rescued by oral tracheal intubation. Tracheal stent extraction was scheduled to relieve the laryngeal edema. Since there was a risk of tracheal restenosis because of the possibility of accidental evulsion of the orally tracheal tube which intubated to secure an emergency airway and tracheal stent extraction, two gum elastic bougies were inserted through the oral tracheal tube and tracheostomy orifice to facilitate re-intubation. After extraction of the tracheal stent, airway openness was maintained and tracheostomy was completed without any complication. CONCLUSION: Successful management of tracheal stent extraction was performed using a double gum elastic bougie technique.

Risk factors of cardiac arrest and failure to achieve return of spontaneous circulation during anesthesia: a 20-year retrospective observational study from a tertiary care university hospital.

PURPOSE: There is still a lack of robust data on the epidemiology of cardiac arrest during anesthesia. We investigated the frequency and risk factors of cardiac arrest during anesthesia over the past two decades at a tertiary care university hospital in Japan. METHODS: We retrospectively analyzed 111,851 anesthesia records of patients who underwent surgery under anesthesia between 2000 and 2019. Cardiac arrest cases were classified according to the patient's background, surgical status, main cause and initial rhythm of cardiac arrest, and the presence of the return of spontaneous circulation (ROSC). Univariate and multivariate logistic regression analyses were used to identify the risk factors of cardiac arrest and failure to achieve ROSC. RESULTS: Ninety cardiac arrest cases during anesthesia were identified. The incidence of cardiac arrest was 8.05 per 10,000 anesthetics (95% CI, 6.54-9.90). There were 6 anesthesia-related cardiac arrests and 9 anesthesia-contributory cardiac arrests. The most common cause of cardiac arrest was blood loss. American Society of Anesthesiologists physical status 4-5, emergency surgery, and cardiovascular surgery were identified as independent risk factors of cardiac arrest. American Society of Anesthesiologists physical status 4-5, blood loss-induced cardiac arrest, and non-shockable rhythm were independently associated with failure to achieve ROSC. CONCLUSION: Blood loss was the most common cause of cardiac arrest and blood loss-induced cardiac arrest was independently associated with failure to achieve ROSC. Further improvements in treatment strategies for bleeding may reduce the future incidence of cardiac arrest and death during anesthesia.

Aerosol boxes decrease aerosol exposure only in depressurized rooms during aerosol-generating procedures in a simulation study.

PURPOSE: The aim of this study was to compare aerosol exposure with or without an aerosol box in a pressurized/depressurized room during aerosol-generating procedures using an experimental model. METHODS: Cake flour (aerosol model) was expelled from an advanced life support training mannequin. The primary outcome measure was the number of 0.3-10 µm-sized particles at three locations corresponding to the physician, medical staff, and environmental aerosol exposure levels. The aerosol dispersion was visualized using a high-resolution video. The number of expelled particles was measured after artificial coughing during simulated tracheal intubation and extubation in four situations, with or without an aerosol box in a pressurized or depressurized room (≤ 2.5 Pa). RESULTS: The particles arising from tracheal intubation at the three positions in the four groups differed significantly in size (p < 0.05). The sizes of particles arising from extubation at the physicians' and medical staff's faces in the four groups differed significantly in size (p < 0.05). Post hoc analysis showed that the counts of all particles at the three positions were significantly lower in the depressurized room with an aerosol box than in the pressurized room without an aerosol box during tracheal intubation (p < 0.05 at three positions) and extubation (p < 0.05) at the physician's and medical staff's positions). Visual assessments supported these results. CONCLUSION: The aerosol box decreased the exposure of the aerosol to the physician, medical staff, and environment during aerosol-generating procedures in the depressurized room only.

Investigations into the efficacy of a novel extubation-aerosol shield: a cough model study.

BACKGROUND: Physicians have had to perform numerous extubation procedures during the prolonged coronavirus disease 2019 (COVID 19) pandemic. Future pandemics caused by unknown pathogen may also present a risk of exposure to infectious droplets and aerosols. AIM: This study evaluated the ability of a newly developed aerosol barrier, "Extubation-Aerosol (EA)-Shield" to provide maximum protection from aerosol exposure during extubation via an aerosolised particle count and high-quality visualisation assessments. METHODS: We employed a cough model having parameters similar to humans and used micron oil aerosol as well as titanium dioxide as aerosol tracers. Aerosol barrier techniques employing a face mask (group M) and EA-Shield (group H) were compared. FINDINGS: The primary outcome was the difference in the number of particles contacting the physician's face before and after extubation. The maximum distances of aerosol dispersal after extubation were measured as the secondary outcomes. All aerosolised particles of the two tracers were significantly smaller in group H than in group M (p < 0.05). In addition, the sagittal and axial maximum distances and sagittal areas of aerosol dispersal for 3, 5, and 10 s after extubation were significantly smaller in group H than in group M (p < 0.05). CONCLUSION: This model indicates that EA-Shield could be highly effective in reducing aerosol exposure during extubation. Therefore, we recommend using it as an aerosol barrier when an infectious aerosol risk is suspected.

Effect of remimazolam on intraoperative neuromonitoring during thyroid surgery: a case series.

Intraoperative neuromonitoring is widely used to prevent accidental injury during thyroid surgery. Anesthesia should be performed without muscle relaxant or agents with high muscle-relaxant potency. Remimazolam, a novel intravenous anesthetic, became available for clinical use in 2020. Remimazolam is an ultra-short-acting benzodiazepine with a very high clearance rate. However, there are very few data regarding its effect on currently used intraoperative neurological monitoring. Five patients underwent thyroid surgery using intraoperative recurrent laryngeal neuromonitoring. In all cases, intubation was performed after the administration of rocuronium. Anesthesia was maintained by continuous administration of remimazolam at the recommended dose and remifentanil, and no additional rocuronium or sugammadex was administered. Recurrent laryngeal nerve activity could be detected at the first stimulus after surgery was started, and monitoring continued thereafter. Intraoperative monitoring was performed without problems and all surgeries were completed without any complications. Anesthesia with remimazolam at the normal dose did not prolong the time to first positive electromyogram in patients undergoing thyroid surgery, and enables intraoperative recurrent laryngeal nerve monitoring to be performed without any serious perioperative adverse events. Remimazolam may provide a comparable quality of anesthesia to that of existing drugs for neuromonitoring during thyroid surgery.

Safety of an improved pediatric epidural tunneling technique for catheter shear.

BACKGROUND: Epidural tunneling could help with prolonged catheterization and be effective in preventing infection and dislodgement. However, epidural tunneling techniques carry a risk of catheter shear or needlestick injuries. AIMS: This study aimed to examine the safety of our epidural tunneling technique in terms of catheter shear. METHODS: This study was designed as a double-blinded, single-crossover, in vitro study. Each of the operators performed two techniques to create a subcutaneous tunnel. We compared outcomes between the control tunneling technique (group C) and our improved technique (group I). Microscopic findings of catheter shear were assessed as the primary outcome. Secondary outcomes included the tension and displacement required to break the epidural catheter and the frequency of catheter breakage due to catheter shear. Data were analyzed using the Fisher's exact test and Mann-Whitney U test. A p-value of <.05 was considered statistically significant. RESULTS: Ten catheters were assessed in each group. The frequency of catheter shear was 10% in group I and 90% in group C (odds ratio, 0.019; 95% confidence interval [CI], 0.01-0.31; p < .001). The frequency of catheter breakage due to catheter shear was significantly lower in group I (0%) than in group C (80%; p < .001). The mean tension and displacement required to break the catheter were significantly higher in group I than in group C (4.13 ± 0.37 N vs. 3.14 ± 1.00 N; mean difference, 0.99 N; 95% CI, 0.25-1.73 N; p = .013 and 222 ± 59.9 mm vs. 122 ± 77.7 mm; mean difference, 100 mm; 95% CI, 34.1-165 mm; p = .005). CONCLUSIONS: Our improved epidural tunneling technique, which was designed for pediatric cases, could reduce the risk of catheter shear.