An Exploration and Technical Notes for Advanced Airway Management on the Ski Slope: A Simulation Experiment

Background. Skiing is a high-risk winter sport, and the rate of injury fatality is the highest compared to other winter sports. During skiing rescue, the harsh natural environments will increase the difficulty of artificial airway establishment. There has been no research focusing on the establishment of the artificial airway during skiing rescue site. This study aims to simulate the real-world scenario, calculating and comparing the operation time of different artificial airways on the cold slope, and to explore the optimal method of establishing artificial airway on the cold slope, sharing our experience, technical notes, and pitfalls we encountered, hoping to help establish a standard operating procedure in advanced airway management on the ski slope. Methods. The simulated human was placed on the cold slope with the head under the feet. Artificial airway was established by the same anesthesiologist using endotracheal intubation (endotracheal intubation group), LMA Supreme laryngeal mask (LMA group), and I-gel laryngeal mask (I-gel group). Each method was repeated 5 times, and the operation time and whether it was successful by one attempt were recorded and compared between groups. Results. Three groups of artificial airway were successful by one attempt.. The bite block dropped and drifted away for one time in the endotracheal intubation group. Operation time is 209.2 ± 32.7 seconds in the endotracheal intubation group, 72.2 ± 3.1 seconds in the LMA group, and 52.6 ± 4.2 seconds in the I-gel group. ANOVA showed that there was a significant difference in the operation time among the three groups ( p < 0.001 ). Tukey’s post hoc test showed that there were statistically significant differences between the endotracheal intubation group and the other two groups in operation time, p < 0.001 , while there was no significant difference between the LMA group and I-gel group ( p = 0.275 ). Conclusion. The artificial airway can be completed by endotracheal intubation and LMA and I-gel laryngeal mask insertion on the cold slope. Artificial airway with the I-gel laryngeal mask takes the shortest time in this study. Extra caution should be paid to slippery and drifting.

Application Effects of Remimazolam and on Elderly Patients Undergoing Hip Replacement

Objective To explore the anesthetic and analgesic effects of remimazolam and propofol in elderly patients undergoing hip replacement and their effects on respiratory and circulatory systems, stress and cognitive function. Methods 60 elderly patients undergoing elective hip replacement in the hospital were selected as the research subjects, and they were divided into the remimazolam group and the propofol group according to the admission sequence of patients. The remimazolam group was anesthetized with remimazolam, and the propofol group was anesthetized with propofol. The anesthesia-related indicators, perioperative pain degree [Visual Analogue Scale (VAS)], circulatory indicators [heart rate, mean arterial pressure (MAP)] before anesthesia (T0), immediately before laryngeal mask insertion (T1), at 5 min after laryngeal mask insertion (T2), at 30 min after laryngeal mask insertion (T3) and at 5 min after laryngeal mask removal (T4), stress response indicators (plasma epinephrine, norepinephrine, cortisol) before anesthesia induction and at 24 h and 72 h after surgery, cognitive function [Mini-Mental State Examination (MMSE)] and adverse reactions were compared between the two groups. Results Among the 60 enrolled patients, only 1 case was excluded due to withdrawal, thus 30 cases in the remimazolam group and 29 cases in the propofol group were included. There were statistically significant differences in the heart rate, MAP, plasma epinephrine, norepinephrine, cortisol and VAS score in the two groups from the aspects of interaction effect and time-point effect (P<0.05). The heart rate and MAP at T1, T2 and T3 in the two groups were significantly decreased compared with those at T0, but the heart rate and MAP in the remimazolam group at T1, T2 and T3 were significantly higher than those in the propofol group (P<0.05). There were no statistical differences in the anesthesia time, awakening time and extubation time between the remimazolam group and the propofol group (P>0.05). The levels of plasma epinephrine, norepinephrine and cortisol in the two groups were significantly higher at 24 h and 72 h after surgery than those before anesthesia induction, and the above levels were significantly lower in the remimazolam group than those in the propofol group (P<0.05). The VAS scores at each time point in the two groups were significantly reduced compared to before surgery, but there was no statistically significant difference between the two groups after surgery (P>0.05). The MMSE scores of the two groups were significantly lower at 1 d and 3 d after surgery compared with those before anesthesia induction, but the score in the remimazolam group was significantly higher than that in the propofol group (P<0.05). In addition, the incidence rates of adverse reactions were significantly lower in the remimazolam group compared to the propofol group (P<0.05). Conclusion Compared with propofol, remimazolam can achieve equivalent anesthetic and analgesic effects in elderly patients undergoing hip replacement. However, the latter one can significantly relieve respiratory and circulatory suppression, stress response and cognitive dysfunction, with good safety. Trial registration Clinical trial ethics committee of Hefei second people's Hospital：2021- scientific research-032 (September 6, 2021).

Size selection of the Ambu AuraOnce laryngeal mask in Chinese men weighing >70 kg: a pilot study

Objective To collect computed tomography data of the laryngeal anatomy of Chinese men and to determine the feasibility of using the size 4 Ambu AuraOnce laryngeal mask (Ambu A/S, Copenhagen, Denmark) in Chinese men weighing >70 kg. Methods This prospective study involved men who underwent surgery from May 2018 to January 2019 at Jinshan Hospital. Pharyngeal and laryngeal parameters were measured by computed tomography. The laryngeal mask insertion success rate, requirement for tracheal tube insertion, laryngeal mask insertion time, fiberoptic bronchoscopy grading, air leakage pressure, and pharyngeal complications were analyzed. Results In a comparison of the size 4 and 5 Ambu AuraOnce devices, the first insertion success rate was 100% and 87% and the three-times insertion success rate was 100% and 93%, respectively, with no significant differences. However, the insertion time was significantly different at 19.6 ± 5.9 versus 31.1 ± 11.2 s, respectively, and the proportions of fiberoptic grading levels were also significantly different. There were no significant differences in the air leakage pressure or pharyngeal complications. Conclusion The size 4 Ambu AuraOnce is more adequate than the size 5 for Chinese men weighing >70 kg, with a shorter insertion time and higher fiberoptic bronchoscopic grading.

The Median Effective Dose (ED50) of cis-Atracurium for Laryngeal Mask Airway Insertion during General Anaesthesia for Patients Undergoing Urinary Surgery

Background In clinical practice, the laryngeal mask airway is an easy-to-use supraglottic airway device. However, the cis- atracurium dosage for laryngeal mask insertion is not standardised. We aimed to determine the optimal dose of cis- atracurium using a sequential method for successful laryngeal mask insertion. Methods : The cohort study protocol is registered at clinicaltrial.gov (NCT-03668262). Twenty-three patients undergoing elective urinary surgery were sequentially administered doses (μg· kg -1 ) of cis- atracurium as follows: 150, 100, 70, 50, 30, and 20. The main outcome was the response to laryngeal mask airway insertion: ≥16 points and <16 points indicated “satisfactory” and “unsatisfactory” responses, respectively. The median effective dose was estimated using the mean of the seven crossovers from “satisfactory” and “unsatisfactory” responses. The primary outcome was to determine the median effective dose (ED50) of cis- atracurium for laryngeal mask airway insertion. Results : The median effective dose of cis- atracurium was 26.5 μg·kg -1 (95% CI 23.6-29.8) using the sequential method. The heart rate was decreased in the 50μg·kg -1 group compared to the 30μg·kg -1 group at timepoints T7, T8, and T10 ( P = 0.0482, P = 0.0460, and P = 0.0236, respectively), but no difference with 20 μg·kg -1 group. The systolic blood pressure was decreased in the 50 μg·kg -1 group compared to the 20 μg·kg -1 group at timepoints T2, T3, T4 ( P = 0.0159, P = 0.0233, and P = 0.0428, respectively). The train-of-four value was significantly lower in the 50 μg·kg -1 group than in the 30 μg·kg -1 group at timepoint T3( P = 0.0326). Conclusions : The ED50 of cis- atracurium was 26.5 μg·kg -1 for laryngeal mask airway insertion.

The Median Effective Dose (ED50) of cis-Atracurium for Laryngeal Mask Airway Insertion during General Anaesthesia for Patients Undergoing Urinary Surgery

Background In clinical practice, the laryngeal mask airway is an easy-to-use supraglottic airway device. However, the cis- atracurium dosage for laryngeal mask insertion is not standardised. We aimed to determine the optimal dose of cis- atracurium using a sequential method for successful laryngeal mask insertion. Method s : The cohort study protocol is registered at clinicaltrial.gov (NCT-03668262). Twenty-three patients undergoing elective urinary surgery were sequentially administered doses (μg· kg -1 ) of cis- atracurium as follows: 150, 100, 70, 50, 30, and 20. The main outcome was the response to laryngeal mask airway insertion: ≥16 points and <16 points indicated “satisfactory” and “unsatisfactory” responses, respectively. The median effective dose was estimated using the mean of the seven crossovers from “satisfactory” and “unsatisfactory” responses. The primary outcome was to determine the median effective dose (ED50) of cis- atracurium for laryngeal mask airway insertion. Result s : The median effective dose of cis- atracurium was 26.5 μg·kg -1 (95% CI 23.6-29.8) using the sequential method. The heart rate was decreased in the 50μg·kg -1 group compared to the 30μg·kg -1 group at timepoints T7, T8, and T10 ( P = 0.0482, P = 0.0460, and P = 0.0236, respectively), but no difference with 20 μg·kg -1 group. The systolic blood pressure was decreased in the 50 μg·kg -1 group compared to the 20 μg·kg -1 group at timepoints T2, T3, T4 ( P = 0.0159, P = 0.0233, and P = 0.0428, respectively). The train-of-four value was significantly lower in the 50 μg·kg -1 group than in the 30 μg·kg -1 group at timepoint T3( P = 0.0326). Conclusion s : The ED50 of cis- atracurium was 26.5 μg·kg -1 for laryngeal mask airway insertion.

Supreme™ laryngeal mask airway insertion requires a lower concentration of sevoflurane than ProSeal™ laryngeal mask airway insertion during target-controlled remifentanil infusion: a prospective randomised controlled study

Background ProSeal (PLMA) and Supreme (SLMA) laryngeal mask airways are effective ventilator devices with distinctive designs that may require different anaesthetics for insertion. Sevoflurane induction provides acceptable conditions for laryngeal mask insertion, and remifentanil significantly decreases the minimum alveolar concentration of sevoflurane required for that insertion. The study aimed to evaluate the optimal end-tidal (ET) sevoflurane concentration for successful insertion of PLMA versus SLMA in patients receiving a remifentanil infusion without a neuromuscular blocking agent. Methods Altogether, 45 patients ASA (American Society Anaesthesiologists) physical status I–II, aged 18–60 years were scheduled for elective ambulatory surgery. Exclusion criteria were a difficult airway, recent respiratory infection, reactive airway, obstructive sleep apnoea syndrome, gastric aspiration’s risk factors, pregnancy, and lactation. Patients were randomly allocated to receive the SLMA or the PLMA. Sevoflurane induction with co-administration of remifentanil was performed at an effect-site concentration of 4 ng mL− 1. ET50 was calculated with a modified Dixon’s up-and-down method (starting at 2.5% in steps of 0.5%). Predetermined sevoflurane concentration was kept constant during the 10 min before LMA insertion. Patient’s response to LMA insertion was classified as “movement” or “no movement”. Sevoflurane ET50 was determined as the midpoint concentration of all the independent pairs that manifested crossover from “movement” to “no movement”. Results The ET50 sevoflurane concentration co-administered with remifentanil required for PLMA insertion was 1.20 ± 0.41% (95% confidence interval 0.76 to 1.63%). For SLMA insertion, it was 0.55 ± 0.38% (95% confidence interval 0.14 to 0.95%) (p = 0.019). Conclusions The end-tidal sevoflurane concentration with co-administered remifentanil required to allow insertion of the SLMA was 54% lower than that needed for inserting the PLMA. Trial registration Clinicaltrials.gov identifier: NCT03003377. Retrospectively registered. Date of registration: December 28, 2016.

The Median Effective Dose (ED50) of cis-Atracurium for Laryngeal Mask Airway Insertion during General Anaesthesia for Patients Undergoing Urinary Surgery

Background In clinical practice, the laryngeal mask airway is an easy-to-use supraglottic airway device. However, the cis- atracurium dosage for laryngeal mask insertion is not standardised. We aimed to determine the optimal dose of cis- atracurium using a sequential method for successful laryngeal mask insertion. Method s : The cohort study protocol is registered at clinicaltrial.gov (NCT-03668262). Twenty-three patients undergoing elective urinary surgery were sequentially administered doses (μg· kg -1 ) of cis- atracurium as follows: 150, 100, 70, 50, 30, and 20. The main outcome was the response to laryngeal mask airway insertion: ≥16 points and <16 points indicated “satisfactory” and “unsatisfactory” responses, respectively. The median effective dose was estimated using the mean of the seven crossovers from “satisfactory” and “unsatisfactory” responses. The primary outcome was to determine the median effective dose (ED50) of cis- atracurium for laryngeal mask airway insertion. Result s : The median effective dose of cis- atracurium was 26.5 μg·kg -1 (95% CI 23.6-29.8) using the sequential method. The heart rate was decreased in the 50μg·kg -1 group compared to the 30μg·kg -1 group at timepoints T7, T8, and T10 ( P = 0.0482, P = 0.0460, and P = 0.0236, respectively), but no difference with 20 μg·kg -1 group. The systolic blood pressure was decreased in the 50 μg·kg -1 group compared to the 20 μg·kg -1 group at timepoints T2, T3, T4 ( P = 0.0159, P = 0.0233, and P = 0.0428, respectively). The train-of-four value was significantly lower in the 50 μg·kg -1 group than in the 30 μg·kg -1 group at timepoint T3( P = 0.0326). Conclusion s : The ED50 of cis- atracurium was 26.5 μg·kg -1 for laryngeal mask airway insertion.