Five-year audit of adherence to an anaesthesia pre-induction checklist.

Although patient safety related to airway management has improved substantially over the last few decades, life-threatening events still occur. Technical skills, clinical expertise and human factors contribute to successful airway management. Checklists aim to improve safety by providing a structured approach to equipment, personnel and decision-making. This audit investigates adherence to our institution's airway checklist from 1 June 2016 to 31 May 2021. Inclusion criteria were procedures requiring airway management and we excluded all procedures performed solely under regional anaesthesia, sedation without airway management or paediatric and cardiovascular surgery. The primary outcome was the proportion of wholly performed pre-induction checklists. Secondary outcomes were the pattern of adherence over the 5 years well as details of airway management, including: airway management difficulties; time and location of induction; anaesthesia teams in operating theatres (including teams for different surgical specialities); non-operating theatre and emergency procedures; type of anaesthesia (general or combined); and urgency of the procedure. In total, 95,946 procedures were included. In 57.3%, anaesthesia pre-induction checklists were completed. Over the 5 years after implementation, adherence improved from 48.3% to 66.7% (p < 0.001). Anticipated and unanticipated airway management difficulties (e.g. facemask ventilation, supraglottic airway device or intubation) defined by the handling anaesthetist were encountered in 4.2% of all procedures. Completion of the checklist differed depending on the time of day (61.3% during the day vs. 35.0% during the night, p < 0.001). Completion also differed depending on location (66.8% in operating theatres vs. 41.0% for non-operating theatre anaesthesia, p < 0.001) and urgency of procedure (65.4% in non-emergencies vs. 35.4% in emergencies, p < 0.001). A mixed-effect model indicated that urgency of procedure is a strong predictor for adherence, with emergency cases having lower adherence (OR 0.58, 95%CI 0.49-0.68, p < 0.001). In conclusion, over 5 years, a significant increase in adherence to an anaesthesia pre-induction checklist was found, and areas for further improvement (e.g. emergencies, non-operating room procedures, night-time procedures) were identified

Parameters influencing the size of chitosan-TPP nano- and microparticles

Chitosan nanoparticles, produced by ionic gelation, are among the most intensely studied nanosystems for drug delivery. However, a lack of inter-laboratory reproducibility and a poor physicochemical understanding of the process of particle formation have been slowing their potential market applications. To address these shortcomings, the current study presents a systematic analysis of the main polymer factors affecting the nanoparticle formation driven by an initial screening using systematic statistical Design of Experiments (DoE). In summary, we found that for a given chitosan to TPP molar ratio, the average hydrodynamic diameter of the particles formed is strongly dependent on the initial chitosan concentration. The degree of acetylation of the chitosan was found to be the second most important factor involved in the system's ability to form particles. Interestingly, viscosimetry studies indicated that the particle formation and the average hydrodynamic diameter of the particles formed were highly dependent on the presence or absence of salts in the medium. In conclusion, we found that by controlling two simple factors of the polymer solution, namely its initial concentration and its solvent environment, it is feasible to control in a reproducible manner the production and characteristics of chitosan particles ranging in size from nano- to micrometres

Inflation volume-balloon diameter and inflation pressure-balloon diameter characteristics of commonly used bronchial blocker balloons for single-lung ventilation in children

BACKGROUND Balloon-tipped bronchial blocker catheters are widely used in pediatric thoracic anesthesia to establish single-lung ventilation. In clinical practice, their balloons demonstrate sudden expansion when inflated with air. In addition, there are concerns related to the high inflation pressures required to expand the balloons. METHODS This in vitro study assessed inflation volume- and inflation pressure-balloon diameter characteristics of the Fogarty arterial embolectomy catheters and Arndt endobronchial blockers. Balloon diameters were photographically assessed during unrestricted volume- and pressure-guided inflation, using air up to the maximum allowed inflation volume as indicated by the manufacturers. Inflation pressures required to open the blocker balloons and inflation pressures needed to expand them to maximum indicated diameter were measured. RESULTS Volume-guided inflation demonstrated a late acute rise in diameter in Fogarty blocker balloons, whereas in the Arndt endobronchial blocker balloons almost linear inflation volume-to-diameter characteristics were observed. Pressure-guided inflation on the other hand demonstrated low-volume, high-pressure characteristics in the Fogarty blocker balloons, with inflation pressures required to expand the balloons to maximum diameters ranging from (mean (SD)) 636 (75) to 947 (152) cmH$_{2}$ O. The inflation pressures required to open the Fogarty blocker balloons were even >1000 cmH$_{2}$ O. Inflation pressures required to expand the 5 F, 7 F, and 9 F Arndt endobronchial blocker balloons to maximum indicated diameter were much lower, namely at 218 (15), 252 (28), and 163 (8) cmH$_{2}$ O. CONCLUSION Based on these study findings, the balloons of Fogarty arterial embolectomy catheters represent high-pressure devices and do not permit stepwise controlled bronchial blockage. The Arndt endobronchial blockers have some advantages over the Fogarty blocker devices, but also represent high-pressure equipment and must be used with caution and limited duration. Manufacturers are asked to design pediatric endobronchial blocker catheters with truly high-volume, low-pressure balloons in accordance to age-related pediatric airway dimensions

Risk patterns of consecutive adverse events in airway management: a Bayesian network analysis.

BACKGROUND Minor adverse airway events play a pivotal role in the safety of airway management. Changes in airway management strategies can reduce such events, but the broader impact on airway management remains unclear. METHODS Minor, frequently occurring adverse airway events were audited before and after implementation of changes to airway management strategies. We used two Bayesian networks to examine conditional probabilities of subsequent airway events and to compute the likelihood of certain events given that certain previous events occurred. RESULTS Independent of sex, age, and American Society of Anesthesiologists physical status, targeted changes to airway management strategies reduced the risk of a first event. Obese patients were an exception, in whom no risk reduction was achieved. Frequently occurring event sequences were identified, for example the most likely event to follow difficult bag-mask ventilation was a Cormack-Lehane grade ≥3, with a risk of 14.3% (95% credible interval [CI], 11.4-17.2%). An impact of the targeted changes was detected on the likelihood of some event sequences, for example the likelihood of no consecutive event after a tracheal tube-related event increased from 43.3% (95% CI, 39.4-47.6%) to 56.4% (95% CI, 52.0-60.5%). CONCLUSIONS Identification of risk patterns and typical structures of event sequences provides a clinically relevant perspective on airway incidents. It further provides a means to quantify the impact of targeted airway management changes. These targeted changes can influence some event sequences, but overall, the benefit results from the cumulative effect of improvements in multiple events. Targeted airway management changes with knowledge of risk patterns and event sequences can potentially further improve patient safety in airway management. CLINICAL TRIAL REGISTRATION NCT02743767

Dimensional compatibility of balloon-tipped bronchial blockers with the pediatric airway anatomy using different recommendations for age-related size selection

BACKGROUND: Age-related recommendations for size selection of bronchial blocker devices are based on a few dated anatomical autopsy and radiological studies determining lower airway dimensions in children. These recommendations are based on anterior-posterior internal bronchial diameters, which are smaller than the more relevant lateral internal bronchial diameters. METHODS: Outer diameters of bronchial blocker balloons inflated with the maximum recommended volume of air were compared to age-related lateral internal bronchial diameters of left and right proximal mainstem bronchi using five different recommendations for age-related size selection of bronchial blocker equipment in children published in the literature. RESULTS: The ratio of outer bronchial blocker diameters inflated with the maximal recommended volume of air to the median lateral internal diameters of the proximal mainstem bronchus ranged from 71.4% to 181.8% for the left side and from 61.7% to 162.6% for the right side. There were many settings where the blocker diameters did not reach the median lateral internal diameters of the proximal mainstem bronchus. This was more often observed for the right than for the left side (37 vs 22 settings). CONCLUSION: This analysis demonstrates that irrespective of the recommendation for size selection used, neither the two balloon-tipped vascular catheters included nor the Arndt endobronchial blockers are ideal for lung isolation in children are compared with the age-related relevant dimensions of pediatric airway anatomy. A redesign of bronchial blocker equipment with age-related anatomically based high-volume, low-pressure blocker balloons made from ultrathin membranes and with smaller catheters would be desirable

Optimisation of airway management strategies: a prospective before-and-after study on events related to airway management

BACKGROUND Poor medical outcomes often result from series of minor events. The present study assessed events related to airway management to determine whether targeted changes to departmental strategies for airway management can reduce the incidence. METHODS This prospective before-and-after study was performed with ethics committee approval and written informed consent from patients. Major and minor events related to airway management were prospectively recorded for 9 weeks. After implementation of changes to departmental strategies for airway management, events were again prospectively recorded over 9 weeks. Primary outcome was number of cases with events. Secondary outcomes were various predefined events. RESULTS At study baseline, 3668 cases and at follow-up 3786 cases were assessed. Cases with events decreased from 566 (15.4%) to 433 (11.4%) (risk ratio [RR]=0.74; 95% confidence interval [CI], 0.66-0.83; P<0.01). As secondary outcomes, the following events decreased: Cormack-Lehane grade 3 or 4 (4.3-2.9%; RR=0.67; 95% CI, 0.52-0.85; P<0.01); difficult bag-mask ventilation (3.8-2.7%; RR=0.69; 95% CI, 0.54-0.89; P<0.01); hypoxaemia (3.8-2.9%; RR=0.75; 95% CI, 0.59-0.96; P=0.03); unplanned use of special equipment (3.2-2.0%; RR=0.62; (95% CI, 0.47-0.83; P<0.01); oesophageal intubation (1.3-0.8%; RR=0.61; 95% CI, 0.39-0.96; P=0.03); bleeding (0.8-0.2%; RR=0.30; 95% CI, 0.14-0.63; P<0.01); insufficient spontaneous breathing (0.3-0.0%; RR=0.09; 95% CI, 0.01-0.68; P<0.01); communication errors (0.1-0.0%; RR=0; 95% CI, 0-NA; P=0.03). CONCLUSIONS Implementation of changes to departmental strategies for airway management significantly reduced cases with events related to airway management. Analysis of events and implementation of strategies that specifically target identified issues might be key to improving airway management. CLINICAL TRIAL REGISTRATION NCT02743767