Effect of different lung recruitment strategies and airway device on oscillatory mechanics in children under general anaesthesia.

BACKGROUND: Atelectasis has been reported in 68 to 100% of children undergoing general anaesthesia, a phenomenon that persists into the recovery period. Children receiving recruitment manoeuvres have less atelectasis and fewer episodes of oxygen desaturation during emergence. The optimal type of recruitment manoeuvre is unclear and may be influenced by the airway device chosen. OBJECTIVE: We aimed to investigate the different effects on lung mechanics as assessed by the forced oscillation technique (FOT) utilising different recruitment strategies: repeated inflations vs. one sustained inflation and different airway devices, a supraglottic airway device vs. a cuffed tracheal tube. DESIGN: Pragmatic enrolment with randomisation to the recruitment strategy. SETTING: We conducted this single-centre trial between February 2020 and March 2022. PARTICIPANTS: Seventy healthy patients (53 boys) aged between 2 and 16 years undergoing general anaesthesia were included. INTERVENTIONS: Forced oscillations (5 Hz) were superimposed on the ventilator waveform using a customised system connected to the anaesthesia machine. Pressure and flow were measured at the inlet of the airway device and used to compute respiratory system resistance and reactance. Measurements were taken before and after recruitment, and again at the end of surgery. MAIN OUTCOME MEASURES: The primary endpoint measured is the change in respiratory reactance. RESULTS: Statistical analysis (linear model with recruitment strategy and airway device as factors) did not show any significant difference in resistance and reactance between before and after recruitment. Baseline reactance was the strongest predictor for a change in reactance after recruitment: prerecruitment Xrs decreased by mean (standard error) of 0.25 (0.068) cmH 2 O s l -1 per  1 cmH 2 O -1  s l -1 increase in baseline Xrs ( P  < 0.001). After correcting for baseline reactance, the change in reactance after recruitment was significantly lower for sustained inflation compared with repeated inflation by mean (standard error) 0.25 (0.101) cmH 2 O ( P  = 0.0166). CONCLUSION: Although there was no significant difference between airway devices, this study demonstrated more effective recruitment via repeated inflations than sustained inflation in anaesthetised children. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12619001434189.

Ventilation strategies for front of neck airway rescue: an in silico study.

BACKGROUND: During induction of general anaesthesia a 'cannot intubate, cannot oxygenate' (CICO) situation can arise, leading to severe hypoxaemia. Evidence is scarce to guide ventilation strategies for small-bore emergency front of neck airways that ensure effective oxygenation without risking lung damage and cardiovascular depression. METHODS: Fifty virtual subjects were configured using a high-fidelity computational model of the cardiovascular and pulmonary systems. Each subject breathed 100% oxygen for 3 min and then became apnoeic, with an obstructed upper airway. When arterial haemoglobin oxygen saturation reached 40%, front of neck airway access was simulated with various configurations. We examined the effect of several ventilation strategies on re-oxygenation, pulmonary pressures, cardiovascular function, and oxygen delivery. RESULTS: Re-oxygenation was achieved in all ventilation strategies. Smaller airway configurations led to dynamic hyperinflation for a wide range of ventilation strategies. This effect was absent in airways with larger internal diameter (≥3 mm). Intrapulmonary pressures increased quickly to supra-physiological values with the smallest airways, resulting in pronounced cardio-circulatory depression (cardiac output <3 L min-1 and mean arterial pressure <60 mm Hg), impeding oxygen delivery (<600 ml min-1). Limiting tidal volume (≤200 ml) and ventilatory frequency (≤8 bpm) for smaller diameter cannulas reduced dynamic hyperinflation and gas trapping, preventing cardiovascular depression. CONCLUSIONS: Dynamic hyperinflation can be demonstrated for a wide range of front of neck airway cannulae when the upper airway is obstructed. When using small-bore cannulae in a CICO situation, ventilation strategies should be chosen that prevent gas trapping to prevent severe adverse events including cardio-circulatory depression.

Use of an Ultra-slim Gastroscope to Accomplish Endoscopist-Facilitated Rescue Intubation During ERCP: A Novel Approach to Enhance Patient and Staff Safety.

BACKGROUND: ERCP is often performed under monitored anesthesia care (MAC) rather than general anesthesia (GA), with patients positioned semi-prone on the fluoroscopy table. Rarely, a MAC ERCP must be converted to GA due to hypoxia or retained food in the stomach. In these circumstances, standard intubation is associated with a significant delay and potential for patient/staff injury during repositioning. We report a novel endoscopist-driven approach to intubation during ERCP using an ultra-slim, flexible gastroscope with an endotracheal tube backloaded onto it. MATERIALS AND METHODS: We identified patients who underwent ERCP from 2014 to 2019, and MAC to GA conversion events. Mode of intubation (standard vs. endoscopist-facilitated) and patient/procedure characteristics were evaluated. All endoscopist-facilitated intubations were performed under anesthesiologist supervision. RESULTS: A total of 3409 patients underwent ERCP; 1568 (46%) GA and 1841 (54%) MAC. Of these, 42 (2.3%) required intubation during ERCP and 16 underwent endoscopist-facilitated intubation due to retained food in the stomach and/or hypoxia. In 3 patients, aspirated material was suctioned from the trachea and bronchi using the ultra-slim gastroscope. Immediate post-procedure extubation was successful in all endoscopist-facilitated intubation patients and none exhibited radiographic evidence of aspiration pneumonia. CONCLUSIONS: Endoscopist-facilitated intubation using an ultra-slim flexible gastroscope is feasible and expeditious for MAC to GA conversion during ERCP. This technique is readily accomplished in the semi-prone position, while standard intubation requires patient transfer from fluoroscopy table to gurney, with associated delay/risks. These data suggest that further study of this approach is warranted, and this may be the most favorable approach for intubation during ERCP.

A pharmacodynamic model of tidal volume and inspiratory sevoflurane concentration in children during spontaneous breathing.

PURPOSE: High concentrations of sevoflurane causes respiratory depression, mainly due to the decrease in tidal volume (TV) during spontaneous ventilation. The purpose of this study was to identify clinical variables that affect the relationship between TV and sevoflurane concentration, and to establish a population pharmacodynamic modelling approach to TV and sevoflurane concentration in children. A prospective observational study involving 48 patients (≤ 6 years of age) scheduled to undergo general anesthesia using laryngeal mask airway was performed. When the inspiratory sevoflurane concentration reached 2 vol%, the vaporizer was increased to 4 vol% for 5 min, then sevoflurane was decreased to 2 vol% for 5 min. During the study period, TV, end-tidal carbon dioxide, and sevoflurane concentration were recorded every 30 s. Pharmacodynamic analysis using a sigmoid Emax model was performed to assess the TV-sevoflurane concentration relationship. To collapse hysteresis of the pharmacokinetic and pharmacodynamic relationship, the semicompartmental model was applied which does not require a structural model for equilibration delay causing the hysteresis. TV decreased with increasing inspiratory sevoflurane concentrations. Hysteresis between the TV and sevoflurane concentration was observed and was accounted for when the model was developed. Initial TV and maximal reduction in TV were related to body weight. The γ (a steepness of the concentration-response relation curve) was 8.78 and the keo, (a first-order rate constant determining the equilibrium between the end-tidal sevoflurane concentration and effect site sevoflurane concentration) was 2.27 min-1. Changes in TV were correlated with sevoflurane concentration with spontaneous breathing during sevoflurane anesthesia. The initial and maximal TV were related to body weight, in a pediatric population.

The Ventilator Management Team: Repurposing Anesthesia Workstations and Personnel to Combat COVID-19.

The coronavirus disease 2019 pandemic resulted in unprecedented numbers of patients with respiratory failure requiring ventilatory support. The number of patients who required critical care quickly outpaced the availability of intensive care unit (ICU) beds. Consequently, health care systems had to creatively expand critical care services into alternative hospital locations with repurposed staff and equipment. Deploying anesthesia workstations to the ICU to serve as mechanical ventilators requires equipment preparation, multidisciplinary planning, and targeted education. We aim to contextualize this process, highlighting major differences between anesthesia workstations and ICU ventilators, and to share the insights gained from our experiences creating an anesthesia provider-based ventilator management team.

Prospective, Randomized Comparison of the i-gel and the Self-Pressurized air-Q Intubating Laryngeal Airway in Elderly Anesthetized Patients.

BACKGROUND: Age-related changes in upper airway anatomy may affect the overall performance of supraglottic airways significantly. The clinical performance of the i-gel and the self-pressurized air-Q intubating laryngeal airways with noninflatable cuffs for elderly populations remains unknown, unlike in children. Thus, we performed a prospective, randomized comparison of these 2 supraglottic airways in elderly patients undergoing general anesthesia. METHODS: We recruited 100 patients, 65-90 years of age, who were scheduled for elective surgery under general anesthesia with muscle relaxation. The enrolled patients were allocated to the i-gel or self-pressurized air-Q group. We assessed oropharyngeal leak pressure as the primary outcome and fiberoptic view after placement and fixation of the airway and at 10 minutes after the initial assessment. The fiberoptic view was scored using a 5-point scale as follows: vocal cords not visible; vocal cords and anterior epiglottis visible, >50% visual obstruction of epiglottis to vocal cords; vocal cords and anterior epiglottis visible, <50% visual obstruction of epiglottis to vocal cords; vocal cords and posterior epiglottis visible; and vocal cords visible. We also investigated success rate and ease of insertion, insertion time, and manipulations during insertion as insertion variables, complications during maintenance and emergence periods, and postoperative pharyngolaryngeal complications including sore throat, dysphagia, and dysphonia. RESULTS: After assessing for eligibility, 48 patients were allocated to each group. Oropharyngeal leak pressures were significantly higher in the i-gel group than in the self-pressurized air-Q group (P < .001) at the 2 measurement points. The raw mean difference at initial assessment and the median difference after 10 minutes were 5.5 cm H2O (95% confidence interval, 3.3-7.6 cm H2O) and 5.0 (95% confidence interval, 2.0-7.0 cm H2O), respectively. The initial scores of fiberoptic view were similar in the 2 groups. However, the self-pressurized air-Q supraglottic airway provided a significantly improved fiberoptic view at 10 minutes after initial assessment (P = .030). We found no statistically significant differences in insertion variables and complications between the 2 groups. CONCLUSIONS: The i-gel provided better sealing function than the self-pressurized air-Q supraglottic airway according to the high oropharyngeal leak pressures in elderly patients during general anesthesia. The self-pressurized air-Q supraglottic airway had improved fiberoptic views in elderly patients during general anesthesia.

LMA Gastro™ airway is feasible during upper gastrointestinal interventional endoscopic procedures in high risk patients: a single-center observational study.

BACKGROUND: Nonoperating room anesthesia during gastroenterological procedures is a growing field in anesthetic practice. While the numbers of patients with severe comorbidities are rising constantly, gastrointestinal endoscopic interventions are moving closer to minimally invasive endoscopic surgery. The LMA Gastro™ is a new supraglottic airway device, developed specifically for upper gastrointestinal endoscopy and interventions. The aim of this study was to evaluate the feasibility of LMA Gastro™ in patients with ASA physical status ≥3 undergoing advanced endoscopic procedures. METHODS: We analyzed data from 214 patients retrospectively who received anesthesia for gastroenterological interventions. Inclusion criteria were upper gastrointestinal endoscopic interventions, airway management with LMA Gastro™ and ASA status ≥3. The primary outcome measure was successful use of LMA Gastro™ for airway management and endoscopic intervention. RESULTS: Thirtyone patients with ASA physical status ≥3, undergoing complex and prolonged upper gastrointestinal endoscopic procedures were included. There were 7 endoscopic retrograde cholangiopancreatographies, 7 peroral endoscopic myotomies, 5 percutaneous endoscopic gastrostomies and 12 other complex procedures (e.g. endoscopic submucosal dissection, esophageal stent placement etc.). Of these, 27 patients were managed successfully using the LMA Gastro™. Placement of the LMA Gastro™ was reported as easy. Positive pressure ventilation was performed without difficulty. The feasibility of the LMA Gastro™ for endoscopic intervention was rated excellent by the endoscopists. In four patients, placement or ventilation with LMA Gastro™ was not possible. CONCLUSIONS: We demonstrated the feasibility of the LMA Gastro™ during general anesthesia for advanced endoscopic procedures in high-risk patients. TRIAL REGISTRATION: German Clinical Trials Register (DRKS00017396) Date of registration: 23rd May 2019, retrospectively registered.

Computerized 4-choice reaction time test for the measurement of psychomotor recovery after general anesthesia.

The recovery of patients after general anesthesia is usually estimated by using clinical scores. Since there is a lack of objective methods for assessing psychomotor recovery, the aim of this study was to evaluate three psychological tests for this purpose. Patients, scheduled for ambulatory gynecological surgery, underwent 3 standard psychological tests before (T1), 15 min after the surgery (T2) and on discharge from the recovery room (T3). The tests used were Wechsler memory scale (test 1, working memory capacity), d2-test (test 2, concentration endurance) and computer-based 4-choice-reaction time (4CRT, test 3, reaction time) as well as Postanesthesia Discharge Scoring System (PADSS). The same test battery was used in healthy female volunteers, all test results were compared at the different time points. In 109 patients, working memory capacity and concentration (tests 1 and 2) decreased, the reaction time (test 3) was prolonged at T2 in comparison with T1 and T3 (P < 0.01). PADSS increased from 8 (T2) to 10 (T3) (medians, P < 0.001). Fifty-seven healthy volunteers demonstrated a practice effect in all 3 tests through the course of the study (P <0.01). 4CRT test had shortest duration and enabled computerized data processing. All three tests objectively assess the recovery of psychomotor function in patients after general anesthesia, the computer-based 4CRT seems to be the most convenient for the clinical routine.

Nonoperating Room Anesthesia for Interventional Neuroangiographic Procedures: Outcomes of 105 Patients.

BACKGROUND AND AIM: Accurate anesthesia management is of great importance for the success of interventional neuroangiographic procedures (INPs). General anesthesia with endotracheal intubation is the most commonly preferred anesthetic method for these procedures. However, whether laryngeal mask airway (LMA) anesthesia is a suitable and safe option for such cases is unclear. The aims of this study were to report the outcomes of anesthetic management in patients who underwent INP, and to compare endotracheal intubation with LMA anesthesia in terms of anesthesia-related outcomes. METHODS: Data of patients who underwent INP under general anesthesia at interventional neuroangiography unit were retrospectively evaluated. RESULTS: A total of 105 patients with a mean age of 52.9 years were included in the study. All procedures were performed under general anesthesia with using endotracheal tube (n = 79, 75.2%) or laryngeal mask (n = 26, 24.8%). Anesthesia-related complications, including respiratory (laryngospasm,bronchospasm, and desaturation) and circulatory (disrhythmia, hypotension, hypertension), were observed in 20 (19.1%) patients. The 2 airway instruments were similar in age, gender, diagnosis, American Society of Anesthesiologist score, mallampati score, duration of procedure, and duration of anesthesia (P > .05). Anesthesia-related complications were more common in LMA group compared with patients who were intubated using endotracheal tube (P = .003). CONCLUSIONS: Anesthesia management in INPs carries many challenges for anesthesiologists, due to the need of exact immobility during the procedure and potential procedure-related risks such as vasculary perforation and bleeding. General anesthesia using endotracheal intubation seems to be more secure, in comparison to LMA anesthesia.

Midazolam Premedication Facilitates Mask Ventilation During Induction of General Anesthesia: A Randomized Clinical Trial.

BACKGROUND: During induction of general anesthesia, proper mask ventilation is crucial for supplying sufficient oxygen to unconscious patients. Midazolam has a relaxing effect on airway muscles. We hypothesized that sedative premedication with midazolam would facilitate mask ventilation during anesthetic induction. METHODS: Patients undergoing elective surgery under general anesthesia were randomized into 2 groups. The midazolam group received midazolam premedication at the reception area, 3 minutes before transfer to the operating room. Patients in the control group were treated with normal saline as a placebo. The primary outcome was difficulty of mask ventilation during induction, as evaluated using the Warters scales. RESULTS: A total of 97 patients completed the analysis: 49 in the control group and 48 in the midazolam group. The patients in the midazolam group showed a significantly lower mask ventilation difficulty score on the Warters scale than that of the control group (mean [standard deviation], 0.92 [1.13] vs 0.19 [0.57]; estimated difference [95% confidence interval], 0.73 [0.37-1.09]; P < .001). The incidence of difficult mask ventilation (≥2 Warters scale) was significantly lower in the midazolam group than in the control group (risk ratio [95% confidence interval], 0.15 [0.03-0.72]; P = .015). CONCLUSIONS: This randomized clinical trial demonstrated that midazolam premedication enhanced mask ventilation during induction of general anesthesia.

The distance between the glottis and the cuff of a tracheal tube placed through three supraglottic airway devices in children: A randomised controlled trial.

BACKGROUND: After tracheal tube insertion via various types of supraglottic airway devices, the distance from the tube cuff to the vocal cords has not been evaluated in children. OBJECTIVES: The aim of this study was to evaluate the position of a tracheal tube cuff relative to the glottis in children when one of three supraglottic airway devices (I-gel, AuraGain and air-Q laryngeal airway) are used as intubation conduits. DESIGN: A randomised controlled trial. SETTING: Tertiary children's hospital. PATIENTS: Children aged less than 7 years. INTERVENTION: In vivo fibre-optic assessment and in vitro measurement. MAIN OUTCOME MEASURES: The main outcome was the safety margin: the distance between the ventilation outlet of the supraglottic airway device and the beginning of the proximal cuff minus that from the ventilation outlet to the glottis. The maximum inner diameter of the cuffed tracheal tube that could be inserted, the fibre-optic view score and the oropharyngeal leak pressure were also evaluated. RESULTS: The three devices exhibited significant differences in the distance from the ventilation outlet to the glottis (mean ±â€ŠSD): I-gel 3.6 ±â€Š0.6 cm, AuraGain 3.8 ±â€Š0.7 cm, air-Q 2.8 ±â€Š1.0 cm (P < 0.001). The safety margin was greatest with the air-Q and narrowest with the I-gel: I gel 1.9 ±â€Š1.1 cm, AuraGain 4.4 ±â€Š0.7 cm and air-Q 7.9 ±â€Š1.1 cm. Using the AuraGain and air-Q, the cuffs of the tracheal tubes were predicted to be located below the glottis with one-size and two-size smaller tracheal tubes in all patients. However, using I-gel, the cuffs would be below the glottis in 69% (95% CI 49.6 to 84.5) and 29% (95% CI 14.0 to 48.4) of the patients with a one-size and two-size smaller tube, respectively. CONCLUSION: The AuraGain and air-Q are well tolerated intubating conduits. The possibility of vocal cord damage is higher when the I-gel is used. TRIAL REGISTRATION: www.clinicaltrials.gov (number: NCT03156166).

Comparison of the clinical performance of i-gel and Ambu AuraGain in children: A randomised noninferiority clinical trial.

BACKGROUND: Supraglottic airway devices are commonly used in general anaesthesia in children. The AuraGain is a newly developed disposable second-generation supraglottic airway device with an inflatable cuff and a gastric port. OBJECTIVE: To confirm our hypothesis that the oropharyngeal leak pressure (OLP) of the AuraGain would be noninferior to that of the i-gel in paediatric patients. DESIGN: A single-blinded, randomised, noninferiority, clinical trial. SETTING: Single-centre trial from January to March 2017. PATIENTS: One hundred paediatric patients (American Society of Anesthesiologists' physical status 1 to 3), aged up to 12 years old, and body weight of 5 to 30 kg requiring a supraglottic airway for elective surgery with an expected surgery time of less than 2 h under general anaesthesia. INTERVENTION: The patients were randomised to allocation to the AuraGain group or the i-gel group. The device size (1.5 to 2.5) used in each group was based on the manufacturer's recommendation. MAIN OUTCOME MEASURES: The primary outcome measure was OLP immediately after insertion, with a predefined noninferiority margin of 3 cmH2O. RESULTS: The OLP immediately after insertion was lower for the AuraGain than for the i-gel (17.1 vs. 23.0 cmH2O; mean difference: -5.9 cmH2O; 95% confidence interval: -8.5 to -3.3 cmH2O; P = 0.98 and <0.001 for noninferiority and superiority, respectively). The first-attempt success rate (AuraGain, 96% vs. i-gel, 90%; P = 0.44) was comparable between the devices. The incidence of blood staining was lower (AuraGain, 6% vs. i-gel, 0%; P = 0.012) and time to insertion was shorter (AuraGain 21.3 vs. i-gel, 17.1 s; P < 0.001) for the i-gel compared with the AuraGain. CONCLUSION: Our noninferiority hypothesis was not adopted. The OLP of the i-gel may be higher than that of the AuraGain, but this superiority hypothesis should be investigated in future trials. The i-gel demonstrated a shorter time to successful placement and lower incidence of blood staining than the AuraGain. TRIAL REGISTRATION: University Hospital Medical Information Network identifier, UMIN000024222.

Effect of positive end-expiratory pressure on gastric insufflation during induction of anaesthesia when using pressure-controlled ventilation via a face mask: A randomised controlled trial.

BACKGROUND: Face mask ventilation (FMV) during induction of anaesthesia is associated with risk of gastric insufflation that may lead to gastric regurgitation and pulmonary aspiration. A continuous positive airway pressure (CPAP) has been shown to reduce gastric regurgitation. We therefore hypothesised that CPAP followed by FMV with positive end-expiratory pressure (PEEP) during induction of anaesthesia would reduce the risk of gastric insufflation. OBJECTIVE: The primary aim was to compare the incidence of gastric insufflation during FMV with a fixed PEEP level or zero PEEP (ZEEP) after anaesthesia induction. A secondary aim was to investigate the effects of FMV with or without PEEP on upper oesophageal sphincter (UES), oesophageal body and lower oesophageal sphincter (LES) pressures. DESIGN: A randomised controlled trial. SETTING: Single centre, Department of Anaesthesia and Intensive Care, Örebro University Hospital, Sweden. PARTICIPANTS: Thirty healthy volunteers. INTERVENTIONS: Pre-oxygenation without or with CPAP 10 cmH2O, followed by pressure-controlled FMV with either ZEEP or PEEP 10 cmH2O after anaesthesia induction. MAIN OUTCOME MEASURES: A combined impedance/manometry catheter was used to detect the presence of gas and to measure oesophageal pressures. The primary outcome measure was the cumulative incidence of gastric insufflation, defined as a sudden anterograde increase in impedance of more than 1 kΩ over the LES. Secondary outcome measures were UES, oesophageal body and LES pressures. RESULTS: The cumulative incidence of gastric insufflation related to peak inspiratory pressure (PIP), was significantly higher in the PEEP group compared with the ZEEP group (log-rank test P < 0.01). When PIP reached 30 cmH2O, 13 out of 15 in the PEEP group compared with five out of 15 had shown gastric insufflation. There was a significant reduction of oesophageal sphincter pressures within groups comparing pre-oxygenation to after anaesthesia induction, but there were no significant differences in oesophageal sphincter pressures related to the level of PEEP. CONCLUSION: Contrary to the primary hypothesis, with increasing PIP the tested PEEP level did not protect against but facilitated gastric insufflation during FMV. This result suggests that PEEP should be used with caution after anaesthesia induction during FMV, whereas CPAP during pre-oxygenation seems to be safe. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02238691.

Cricoid-mental distance-based versus weight-based criteria for size selection of classic laryngeal mask airway in adults: a randomized controlled study.

The optimal size selection of laryngeal mask airway (LMA) based on body weight is not always applicable. This study was prospectively conducted to evaluate the efficacy of cricoid-mental distance-based method versus weight-based method in optimal size selection of LMA in adults. Seventy-four patients (aged from 18 to 65) undergoing ophthalmic surgery were randomly assigned into cricoid-mental (CM) distance-based group or weight-based group to select appropriate size of LMA. The primary outcome was oropharyngeal leak pressure (OLP). Secondary outcomes included overall insertion success rate, number of insertion attempts, time to successful insertion, ease of insertion, score of fiber-optic view, peak inspiratory pressure during mechanical ventilation and postoperative pharyngolaryngeal morbidity. The OLP was significantly higher in CM distance-based group than that in weight-based group (19.38 ± 3.52 vs. 17.50 ± 3.18, P = 0.022). The successful placement at the first attempt in CM distance-based group was dramatically increased as compared with weight-based group (89.2% vs. 62.2%, P = 0.005). The overall success rate of LMA insertion in CM distance-based group was slightly increased in comparison with the weight-based group (100% vs. 91.9%, P = 0.240). There were no significant differences in score of fiber-optic view and postoperative pharyngolaryngeal morbidity between both groups (all P > 0.05). CM distance-based criteria is an alternative choice for optimizing size selection of classic LMA in adults.

Modifiable and Nonmodifiable Factors Associated With Perioperative Failure of Extraglottic Airway Devices.

BACKGROUND: Extraglottic airway device (EGA) failure can be associated with severe complications and adverse patient outcomes. Prior research has identified patient- and procedure-related predictors of EGA failure. In this retrospective study, we assessed the incidence of perioperative EGA failure at our institution and identified modifiable factors associated with this complication that may be the target of preventative or mitigating interventions. METHODS: We performed a 5-year retrospective analysis of adult general anesthesia cases managed with EGAs in a single academic center. Univariable and multivariable logistic regressions were used to identify clinically modifiable and nonmodifiable factors significantly associated with 3 different types of perioperative EGA failure: (1) "EGA placement failure," (2) "EGA failure before procedure start," and (3) "EGA failure after procedure start." RESULTS: A total of 19,693 cases involving an EGA were included in the analysis dataset. EGA failure occurred in 383 (1.9%) of the cases. EGA placement failure occurred in 222 (1.13%) of the cases. EGA failure before procedure start occurred in 76 (0.39%) of the cases. EGA failure after procedure start occurred in 85 (0.43%) of the cases. Factors significantly associated with each type of failure and controllable by the anesthesia team were as follows: (1) EGA placement failure: use of desflurane (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.23-2.25) and EGA size 4 or 5 vs 2 or 3 (OR, 0.07; 95% CI, 0.05-0.10); (2) EGA failure before procedure start: use of desflurane (OR, 2.05; 95% CI, 1.23-3.40) and 3 or more placement attempts (OR, 4.69; 95% CI, 2.57-8.56); and (3) EGA failure after procedure start: 3 or more placement attempts (OR, 2.06; 95% CI, 1.02-4.16) and increasing anesthesia time (OR, 1.35; 95% CI, 1.17-1.55). CONCLUSIONS: The overall incidence of EGA failure was 1.9%, and EGA placement failure was the most common type of failure. We also found that use of desflurane and use of smaller EGA sizes in adult patients were factors under the direct control of anesthesia clinicians associated with EGA failure. An increasing number of attempts at EGA placement was associated with later device failures. Our findings also confirm the association of EGA failure with previously identified patient- and procedure-related factors such as increased body mass index, male sex, and position other than supine.

Changing Default Ventilator Settings on Anesthesia Machines Improves Adherence to Lung-Protective Ventilation Measures.

Perioperative lung-protective ventilation (LPV) can reduce perioperative pulmonary morbidity. We hypothesized that modifying default anesthesia machine ventilator settings would increase the use of intraoperative LPV. Default tidal volume settings on our anesthesia machines were decreased from 600 to 400 mL, and default positive end-expiratory pressure was increased from 0 to 5 cm H2O. This modification increased mean positive end-expiratory pressure from 3.1 to 5.0 cm H2O and decreased mean tidal volume from 8.2 to 6.7 mL/kg predicted body weight. Notably, increased adherence to LPV from 1.6% to 23.0% occurred quickly with the rate of increase more than doubling from 1.8% to 3.9% per year.

A retrospective study of the impact of supraglottic airway devices on the appearance of neck masses in children undergoing serial magnetic resonance imaging.

BACKGROUND: General anesthesia and sedation are used routinely for magnetic resonance imaging (MRI) studies in children to optimize image quality. Airway devices such as supraglottic airways (SGAs) can alter the appearance of cervical soft tissue regions on an MRI and increase the risk of misdiagnosis. This phenomenon has not been well described in vivo. AIMS: We conducted this retrospective study to determine how often SGAs affected the appearance of neck masses in children who received multiple anesthetics for MRIs with and without an SGA. METHODS: We retrieved data on children 17 years old and younger who had multiple MRIs between January 2005 and January 2015. Inclusion criteria were patients with neck masses who had a SGA for at least one MRI and either a natural airway or endotracheal tube (ETT) for another MRI. We reviewed MRI images and imaging reports to determine if SGAs affected the appearance of neck masses. RESULTS: Twelve of the 921 patients who received anesthesia for neck MRIs during the study period met the inclusion criteria. SGAs affected the appearance of the neck mass in 11 of the 12 patients. CONCLUSIONS: Supraglottic airways can significantly alter the appearance of neck masses in children undergoing MRIs and affect radiologists' ability to assess those masses. Communication with the radiologist prior to the induction of anesthesia is crucial when using supraglottic devices in this patient population. It may be more prudent to use a different airway device and/or anesthetic technique when MRIs of these neck masses are undertaken.

Comparison of the laryngeal mask airway supreme and the i-gel in paralysed elderly patients: A randomised controlled trial.

BACKGROUND: The laryngeal mask airway supreme (LMA-S) and i-gel are both popular second-generation supraglottic airway devices that have been widely studied in surgical patients, but their differences in clinical performance in the elderly are not clear. OBJECTIVE: We compared the efficacy and safety of the LMA-S and i-gel in anaesthetised and paralysed elderly patients. DESIGN: A randomised study. SETTING: Single-centre trial, study period January 2014 from to October 2016. PATIENTS: One hundred and six elderly patients who underwent urological or orthopaedic surgery with an expected duration less than 2 h. INTERVENTION: Patients were allocated to either the LMA-S (n = 53) or i-gel (n = 53) group. All insertions were performed in a standardised manner according to the manufacturers' instructions. MAIN OUTCOME MEASURES: Our primary endpoint was the rate of successful insertion at the first attempt. The adequacy of positive pressure ventilation and airway sealing, fibreoptic laryngoscopy grades and stability of airway maintenance during anaesthesia were also assessed. RESULTS: Although the rate of successful insertion at the first attempt was similar between the two groups (94.3 vs. 82.7%, P = 0.072), more patients required device manipulation during insertion with the LMA-S than the i-gel (42.3 vs. 18.9%, P = 0.011). Good fibreoptic laryngoscopy grades were significantly more common with the i-gel than the LMA-S (79.3 vs. 55.8%, P = 0.042), and peak inspiratory pressures were lower in the i-gel group both immediately after insertion and at the end of surgery. Leak pressures were significantly higher in the i-gel group than the LMA-S group, both immediately after insertion and at the end of surgery (25.8 vs. 23.0, P = 0.036; and 28.1 vs. 23.7, P < 0.001, respectively). CONCLUSION: Both the LMA-S and i-gel were used successfully and safely in elderly patients. However, the i-gel demonstrated better airway sealing than the LMA-S at insertion and during maintenance of anaesthesia. TRIAL REGISTRATION: NCT02026791 at clinicaltrial.gov.

The effect of mouth prop on endotracheal tube intracuff pressure in children during dental rehabilitation under general anaesthesia.

Although the endotracheal tube (ETT) cuff may be associated with tracheal morbidity, cuffed tubes may reduce the aspiration risk in oral procedures. Dentists must use a mouth prop to facilitate oral visualization and to protect the oral soft tissues during dental rehabilitation under general anaesthesia (DRGA). The aim of this study was to evaluate the effect of mouth prop on endotracheal tube intracuff pressure in children during DRGA. Two-hundred and three ASA I-II patients, <18 years of age (mean: 5.3 ± 2.4 years) were included in the prospective observational study whose comprehensive dental treatment was performed under general anaesthesia. Following the induction of general anaesthesia, placement of a cuffed endotracheal tube which was an appropriate size for children was fixed. The intracuff pressure was measured intermittently after the intubation (baseline) (T0), immediately after the mouth prop (T1), 30 min after the mouth prop (T2), after taking out the mouth prop (T3) and just before extubation (T4). The mean intracuff pressure was 28.3 ± 2.01 cm H2O at T0. The mean intracuff pressure significantly increased at T1 (30.8 ± 2.7) and T2 (29.6 ± 3.7) compared to T0 (P < 0.001). No significant differences were observed between the duration of the procedure and intracuff pressure or postoperative complications (P > 0.05). Cough, sore throat and nausea were observed in 4, 1 and 5 patients, respectively. Because a mouth prop may increase the intracuff pressure of ETT, strict measurement and readjustment of cuff pressures should be employed when used in children during DRGA.

Comparison of clinical performance of size 1.5 Supreme™ LMA and Proseal™ LMA among Asian children: a randomized controlled trial.

To date, most of the studies on safety and efficacy of supraglottic airway devices were done in Caucasian patients, and the results may not be extrapolated to Asian patients due to the different airway anatomy. We conducted this study to compare Supreme™ LMA (SLMA) and Proseal™ LMA (PLMA) size 1.5 in anaesthetized children among an Asian population. This prospective randomized clinical trial was conducted in a tertiary teaching hospital from September 2013 until May 2016. Sixty children, weighing 5-10 kg, who were scheduled for elective surgery under general anaesthesia were recruited and completed the study. Patients were randomly assigned to have either SLMA or PLMA as the airway device for general anaesthesia, and standard anaesthesia protocol was followed. The primary outcome measured was the oropharyngeal leak pressure (OLP). The rate of successful insertion, insertion time, fibreoptic view of larynx and airway complications for each device were also assessed. There were no statistically significant differences between SLMA and PLMA size 1.5 in oropharyngeal leak pressure [19.1 (± 5.5) cmH2O vs. 19.8 (± 4.5) cmH2O, p = 0.68]. Secondary outcomes including time to insertion [20.8 (± 8.3) vs. 22.1 (± 8.3) s, p = 0.57], first attempt success rate for device insertion, fibreoptic view of larynx, and airway complications were also comparable between the two devices. We found that all the patients who had a failed device insertion (either PLMA or SLMA) were of a smaller size (5-6.2 kg). The oropharyngeal leak pressure of the SLMA 1.5 was comparable with the PLMA 1.5, and both devices were able to maintain an airway effectively without significant clinical complications in anaesthetized children from an Asian population.