Cocaine versus xylometazoline to prevent epistaxis after nasotracheal intubation: A randomized trial.

BACKGROUND: Nasotracheal intubation is associated with a risk of epistaxis. Several drugs, including cocaine and xylometazoline may be used as decongestants prior to nasotracheal intubation to prevent this. We hypothesized that xylometazoline would prevent epistaxis more effectively than cocaine, demonstrated by a lower proportion of patients with bleeding after nasotracheal intubation. METHODS: We conducted a single-center, outcome assessor and analyst-blinded, clinical randomized controlled trial following approval from the local research ethics committee and the national medicine agency. Written informed consent was obtained from all patients. Patients scheduled for surgery under general anesthesia with nasotracheal intubation were randomized to receive either 2 mL 4% cocaine or 2 mL 0.05% xylometazoline prior to nasotracheal intubation. Immediately following intubation, epistaxis was evaluated by the blinded intubating anesthetist on a four-point scale. We measured heart rate and blood pressure the first 5 min after drug administration. Adverse events were followed up after 24 h. RESULTS: A total of 53 patients received cocaine and 49 patients received xylometazoline. Bleeding occurred in 32 patients receiving cocaine (60.4%) and in 34 patients receiving xylometazoline (69.4%) (p = .41, Fisher's exact test) with a difference of 9.0% (95% CI: -9.4% to 27%). There was no statistically significant difference between groups regarding the heart rate or blood pressure. No adverse cardiac events were recorded in either group. CONCLUSION: We found no statistically significant difference between cocaine and xylometazoline in preventing epistaxis after nasotracheal intubation, and the choice of vasoconstrictor should be based on other considerations, such as pricing, availability and medicolegal issues.

Improvements in cuirass ventilation for airway surgery: origins in Copenhagen on the 70th anniversary of the first intensive care unit.

The first modern intensive care unit was established in Copenhagen 70 yr ago. This cornerstone of anaesthesia was largely based on experience gained using positive pressure ventilation to save hundreds of patients during the polio epidemic in 1952. Ventilation approaches, monitoring techniques, and pharmacological innovations have developed to such an extent that cuirass ventilation, which proved inadequate during the polio epidemic, might now have novel applications for both anaesthesia and treatment of the critically ill.

Transcutaneous carbon dioxide monitoring during prolonged apnoea with high-flow nasal oxygen.

BACKGROUND: The duration of apnoeic oxygenation with high-flow nasal oxygen is limited by hypercapnia and acidosis and monitoring of arterial carbon dioxide level is therefore essential. We have performed a study in patients undergoing prolonged apnoeic oxygenation where we monitored the progressive hypercapnia with transcutaneous carbon dioxide. In this paper, we compared the transcutaneous carbon dioxide level with arterial carbon dioxide tension. METHODS: This is a secondary publication based on data from a study exploring the limits of apnoeic oxygenation. We compared transcutaneous carbon dioxide monitoring with arterial carbon dioxide tension using Bland-Altman analyses in anaesthetised and paralysed patients undergoing prolonged apnoeic oxygenation until a predefined limit of pH 7.15 or PCO2 of 12 kPa was reached. RESULTS: We included 35 patients with a median apnoea duration of 25 min. Mean pH was 7.14 and mean arterial carbon dioxide tension was 11.2 kPa at the termination of apnoeic oxygenation. Transcutaneous carbon dioxide monitoring initially slightly underestimated the arterial tension but at carbon dioxide levels above 10 kPa it overestimated the value. Bias ranged from -0.55 to 0.81 kPa with limits of agreement between -1.25 and 2.11 kPa. CONCLUSION: Transcutaneous carbon dioxide monitoring provided a clinically acceptable substitute for arterial blood gases but as hypercapnia developed to considerable levels, we observed overestimation at high carbon dioxide tensions in patients undergoing apnoeic oxygenation with high-flow nasal oxygen.

Infrared flashing light through the cricothyroid membrane as guidance to awake intubation with a flexible bronchoscope: A randomised cross-over study.

BACKGROUND: In case of distorted airway anatomy, awake intubation with a flexible bronchoscope can be extremely difficult or even impossible. To facilitate this demanding procedure, an infrared flashing light source can be placed on the patient's neck superficial to the cricothyroid membrane. The light travels through the skin and tissue to the trachea, from where it can be registered by the advancing bronchoscope in the pharynx and seen as flashing white light on the monitor. We hypothesised that the application of this technique would allow more proximal and easier identification of the correct pathway to the trachea in patients with severe airway pathology. METHODS: As part of awake intubation, patients underwent insertion of a flexible video bronchoscope via the mouth into the trachea. The procedure was performed twice, in random order in each patient, with and without the aid of the transcutaneous flashing infrared light. All insertions were video recorded to determine at which anatomical landmark within the airway the correct pathway was identified. The videos are accessible via this link: https://airwaymanagement.dk/infrared_comparative. The predefined landmarks were in successive order: oral cavity, oro-pharynx, tip of epiglottis, arytenoid cartilages, false cords, vocal cords and trachea, as well as the spaces between them. RESULTS: Twenty-two patients had a total of 44 awake insertions with the flexible bronchoscope. The median anatomical level, at which correct identification of the trachea was obtained on the monitor, was, past the epiglottis, with the conventional technique, and at the level of the oropharynx, when using the infrared flashing light (p = .005). The time until the flashing light or the vocal cords were seen was 21 (22) S, mean (SD), and 48 (62) S, during the insertion with and without infrared flashing light activated, respectively (p = .005). Endoscopists rated it easier (p = .001) to recognise the entrance to the trachea in the infrared-group. CONCLUSION: During awake intubation of patients with airway pathology, the application of trans-cricothyroid infrared flashing light to guide the insertion of a flexible bronchoscope significantly facilitated the recognition of the pathway into the trachea and the correct advancement of the flexible endoscope. REGISTRATION OF CLINICAL TRIAL: NCT03930550.

Managing Known Difficult Airways in Obstetric Patients Using a Flexible Bronchoscope and IRRIS: A Case-Illustrated Guide for Nonexpert Anesthesiologists, without Surgical Backup.

Pregnancy is associated with anatomical and physiological changes leading to potential difficult airway management. Some pregnant women have known difficult airways and cannot be intubated even with a hyperangulated videolaryngoscope. If neuraxial techniques are also impossible, awake tracheal intubation with a flexible bronchoscope may be one of the few available options to avoid more invasive techniques. The Infrared Red Intubation System (IRRIS) may help nonexpert anesthesiologists in such situations and may enhance the chance of successful intubation increasing safety for the mother and the fetus, especially in hospitals without the ear, nose, and throat surgical backup.

Useful Ultrasonographic Parameters to Predict Difficult Laryngoscopy and Difficult Tracheal Intubation-A Systematic Review and Meta-Analysis.

Unexpected difficult airway management can cause significant morbidity and mortality in patients admitted for elective procedures. Ultrasonography is a promising tool for perioperative airway assessment, nevertheless it is still unclear which sonographic parameters are useful predictors of difficult laryngoscopy and tracheal intubation. To determine the ultrasonographic predictors of a difficult airway that could be applied for routine practice, a systematic review and meta-analysis was conducted. Literature search was performed on PubMED, Web of Science and Embase using the selected keywords. Human primary studies, published in English with the use of ultrasonography to prediction of difficult laryngoscopy or tracheal intubation were included. A total of 19 articles (4,570 patients) were analyzed for the systematic review and 12 articles (1,141 patients) for the meta-analysis. Standardized mean differences between easy and difficult laryngoscopy groups were calculated and the parameter effect size quantified. A PRISMA methodology was used and the critical appraisal tool from Joanna Briggs Institute was applied. Twenty-six sonographic parameters were studied. The overall effect of the distance from skin to hyoid bone (p = 0.02); skin to epiglottis (p = 0.02); skin to the anterior commissure of vocal cords (p = 0.02), pre-epiglottis space to distance between epiglottis and midpoint between vocal cords (p = 0.01), hyomental distance in neutral (p < 0.0001), and extended (p = 0.0002) positions and ratio of hyomental distance in neutral to extended (p = 0.001) was significant. This study shows that hyomental distance in the neutral position is the most reliable parameter for pre-operative airway ultrasound assessment. The main limitations of the study are the small sample size, heterogeneity of studies, and absence of a standardized ultrasonographic evaluation method [Registered at International prospective register of systematic reviews (PROSPERO): number 167931].

Anesthesiologists' airway management expertise: Identifying subjective and objective knowledge gaps.

BACKGROUND: Failure in airway management continues to cause preventable patient harm, and the recommended continuing education is challenged by anesthesiologists' unknown knowledge gaps. This study aimed to identify anesthesiologists' subjective and objective knowledge gaps as well as areas where anesthesiologists are incorrect and unaware. METHODS: An adaptive E-learning program with 103 questions on adult airway management was used for subjective and objective assessment of anesthesiologists' knowledge. All anesthesiologists in the Capital Region of Denmark were invited to participate. RESULTS: The response rate was 67% (191/285). For preoperative planning, participants stated low confidence (subjective assessment) regarding predictors of difficult airway management in particular (69.1%-79.1%). Test scores (objective assessment) were lowest for obstructive sleep apnea as a predictor of difficult airway management (28.8% correct), with participants being incorrect and unaware in 33.5% of the answers. For optimization of basic techniques, the lowest confidence ratings related to patient positioning and prediction of difficulties (57.4%-83.2%), which agreed with the lowest test scores. Concerning advanced techniques, videolaryngoscopy prompted the lowest confidence (72.4%-85.9%), while emergency cricothyrotomy resulted in the lowest test scores (47.4%-67.8%). Subjective and objective assessments correlated and lower confidence was associated with lower test scores: preoperative planning [r = -.58, P < .001], optimization of basic techniques [r = -.58, P = .002], and advanced techniques [r = -.71, P < .001]. CONCLUSION: We identified knowledge gaps in important areas of adult airway management with differing findings from the subjective and objective assessments. This underlines the importance of objective assessment to guide continuing education.

A marking of the cricothyroid membrane with extended neck returns to correct position after neck manipulation and repositioning.

BACKGROUND: Emergency front of neck airway access by anaesthetists carries a high failure rate and it is recommended to identify the cricothyroid membrane before induction of anaesthesia in patients with a predicted difficult airway. We have investigated whether a marking of the cricothyroid membrane done in the extended neck position remains correct after the patient's neck has been manipulated and subsequently repositioned. METHODS: The subject was first placed in the extended head and neck position and had the cricothyroid membrane identified and marked with 3 methods, palpation, 'laryngeal handshake' and ultrasonography and the distance from the suprasternal notch to the cricothyroid membrane was measured. The subject then moved off the table and sat on a chair and subsequently returned to the extended neck position and examinations were repeated. RESULTS: Skin markings of all 11 subjects lay within the boundaries of the cricothyroid membrane when the subject was repositioned back to the extended neck position and the median difference between the two measurements of the distance from the suprasternal notch was 0 mm (range 0-2 mm). CONCLUSION: The cricothyroid membrane can be identified and marked with the subject in the extended neck position. Then the patient's position can be changed as needed, for example to the 'sniffing' neck position for conventional intubation. If a front of neck airway access is required during subsequent airway management, the patient can be returned expediently to the extended-neck position, and the marking of the centre of the membrane will still be in the correct place.

Maintaining competence in airway management.

BACKGROUND: Airway management is a defining skill for anaesthesiologists. Anaesthesiologists must maintain and update these crucial skills throughout their career, but how this is best achieved remains unclear. This study aimed to clarify anaesthesiologists' procedural volume, confidence in airway management and their current and preferred future educational strategies. METHODS: A questionnaire was developed consisting of 28 items exploring essential skills in airway management. All anaesthesiologists in the Capital Region of Denmark were invited to participate. RESULTS: The response rate was 84% (240/285). Most anaesthesiologists felt competent to a high or very high degree in basic airway management. Anaesthesiologists from anaesthesia felt confident to a significantly higher degree than those working in the intensive care unit (ICU) regarding the practical aspects of airway management in both the anticipated difficult airway (93% vs 73%, P < .001) and the unanticipated difficult airway (81% vs 61%, P = .002). Both groups performed most of the key advanced techniques ≤4 times yearly, whereas anaesthesiologists from the ICU had a lower and less diverse procedural volume than those working in anaesthesia. The anaesthesiologists preferred training through their daily clinical work, hands-on workshops, and scenario-based simulation training. However, a large discrepancy was identified between the current and the desired level of training. CONCLUSION: The anaesthesiologists felt competent to a high or very high degree in basic airway management but the current procedural volume in advanced airway management causes concern for skill maintenance. Furthermore, we found a gap between the current and the desired level of supplemental training.

Depth to the airway lumen at the level of the cricothyroid membrane measured by ultrasound.

BACKGROUND: Knowing the likely depth to the airway before emergency cricothyroidotomy may improve success in cases where it cannot be measured. Our aim was to measure the depth to the airway at the cricothyroid membrane by ultrasound in a large group of adult patients. METHOD: Prospective, observational study in two centres, Oxford and Gloucester. Patients presenting for a large variety of surgical operations were studied. Patients under 18 years; pregnant; critically ill; had a history of neck surgery were not included. Ultrasound examination was performed pre-operatively while participants lay supine with their head and neck extended, with light transducer pressure. We measured depth to the airway lumen in mm; age; weight; height and sex. RESULTS: In total 352 patients were studied. We found that depth to the airway lumen strongly correlated with weight (r = 0.855, P < 0.001) and to a lesser extent body mass index (r = 0.781, P < 0.001). Statistical analysis produced an equation to predict upper 95% CI of depth to the airway from the patient's weight: Depth to the airway lumen in mm = (0.13 × weight in kg) + 0.86. CONCLUSIONS: If ultrasound measurement is not possible before emergency cricothyroidotomy, the clinician could use our results to predict the depth to the airway by using the patient's weight. If the upper 95% CI were used as the depth of incision, it would enter the airway in 39 out of 40 patients of that weight, without damage to posterior structures in those with a shallower airway.

Point-of-care ultrasound (POCUS) of the upper airway.

Airway management is a critical skill in the practice of several medical specialities including anesthesia, emergency medicine, and critical care. Over the years mounting evidence has showed an increasing role of ultrasound (US) in airway management. The objective of this narrative review is to provide an overview of the indications for point-of-care ultrasound (POCUS) of the upper airway. The use of US to guide and assist clinical airway management has potential benefits for both provider and patient. Ultrasound can be utilized to determine airway size and predict the appropriate diameter of single-lumen endotracheal tubes (ETTs), double-lumen ETTs, and tracheostomy tubes. Ultrasonography can differentiate tracheal, esophageal, and endobronchial intubation. Ultrasonography of the neck can accurately localize the cricothyroid membrane for emergency airway access and similarly identify tracheal rings for US-guided tracheostomy. In addition, US can identify vocal cord dysfunction and pathology before induction of anesthesia. A rapidly growing body of evidence showing ultrasonography used in conjunction with hands-on management of the airway may benefit patient care. Increasing awareness and use of POCUS for many indications have resulted in technologic advancements and increased accessibility and portability. Upper airway POCUS has the potential to become the first-line non-invasive adjunct assessment tool in airway management.

Essential ultrasound techniques of the pediatric airway.

Ultrasound of the airways is a technique which has been described in a number of recent articles and reviews highlighting the diagnostic possibilities and simple methodology. However, there is a paucity of information focusing specifically on such methods in children where equipment, technique, and challenges are different. This review article gives a general overview of the equipment considerations, scanning protocols, and clinical applications in children.

Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae.

OBJECTIVES: To create a state-of-the-art overview of the new and expanding role of ultrasonography in clinical decision-making, intervention and management of the upper and lower airways, that is clinically relevant, up-to-date and practically useful for clinicians. METHODS: This is a narrative review combined with a structured Medline literature search. RESULTS: Ultrasonography can be utilised to predict airway difficulty during induction of anaesthesia, evaluate if the stomach is empty or possesses gastric content that poses an aspiration risk, localise the essential cricothyroid membrane prior to difficult airway management, perform nerve blocks for awake intubation, confirm tracheal or oesophageal intubation and facilitate localisation of tracheal rings for tracheostomy. Ultrasonography is an excellent diagnostic tool in intraoperative and emergency diagnosis of pneumothorax. It also enables diagnosis and treatment of interstitial syndrome, lung consolidation, atelectasis, pleural effusion and differentiates causes of acute breathlessness during pregnancy. Patient safety can be enhanced by performing procedures under ultrasound guidance, e.g. thoracocentesis, vascular line access and help guide timing of removal of chest tubes by quantification of residual pneumothorax size. CONCLUSIONS: Ultrasonography used in conjunction with hands-on management of the upper and lower airways has multiple advantages. There is a rapidly growing body of evidence showing its benefits. TEACHING POINTS: • Ultrasonography is becoming essential in management of the upper and lower airways. • The tracheal structures can be identified by ultrasonography, even when unidentifiable by palpation. • Ultrasonography is the primary diagnostic approach in suspicion of intraoperative pneumothorax. • Point-of-care ultrasonography of the airways has a steep learning curve. • Lung ultrasonography allows treatment of interstitial syndrome, consolidation, atelectasis and effusion.

Airway management in a bronchoscopic simulator based setting: an observational study.

BACKGROUND: Several simulation-based possibilities for training flexible optical intubation have been developed, ranging from non-anatomical phantoms to high-fidelity virtual reality simulators. These teaching devices might also be used to assess the competence of trainees before allowing them to practice on patients. OBJECTIVES: To evaluate the validity of airway simulation as an assessment tool for the acquisition of the preclinical basic skills in flexible optical intubation and to investigate anaesthetists' opinion on airway simulation. DESIGN: Observational study. SETTING: International airway course. PARTICIPANTS: Thirty-six consultants and residents in anaesthesiology. MAIN OUTCOME MEASURES: All participants performed one single procedure on each of the three different simulators. Their video-filmed performances were assessed by two independent, blinded experts and their opinions of simulation were surveyed. RESULTS: The mean score increased 0.33 points after each attempt (P = 0.021). The attitude towards simulation-based training was always more than 4 on a scale from 1 to 5. Only 25% of the procedures were performed to satisfaction with a learning-by-testing effect (P = 0.021). Generalisability coefficient was 0.55, and there was no correlation between the number of clinical procedures performed beforehand and test scores (P = 0.93). CONCLUSION: The increase in mean score is a learning effect indicating that simulator training allows for entry of the learning curve at a higher level. The anaesthetists in our study agreed completely that simulation-based training was useful regardless of the fidelity of the simulator. Local, practical issues such as cost and portability should decide available simulation modalities in each teaching hospital.

Emergency airway access in children--transtracheal cannulas and tracheotomy assessed in a porcine model.

OBJECTIVES: In the rare scenario when it is impossible to oxygenate or intubate a child, no evidence exists on what strategy to follow. AIM: The aim of this study was to compare the time and success rate when using two different transtracheal needle techniques and also to measure the success rate and time when performing an emergency tracheotomy in a piglet cadaver model. METHODS: In this randomized cross-over study, we included 32 anesthesiologists who each inserted two transtracheal cannulas (TTC) using a jet ventilation catheter and an intravenous catheter in a piglet model. Second, they performed an emergency tracheotomy. A maximum of 2 and 4 min were allowed for the procedures, respectively. The TTC procedures were recorded using a video scope. RESULTS: Placement of a transtracheal cannula was successful in 65.6% and 68.8% of the attempts (P = 0.76), and the median duration of the attempts was 69 and 42 s (P = 0.32), using the jet ventilation catheter and the intravenous catheter, respectively. Complications were frequent in both groups, especially perforation of the posterior tracheal wall. Performing an emergency tracheotomy was successful in 97%, in a median of 88 s. CONCLUSIONS: In a piglet model, we found no significant difference in success rates or time to insert a jet ventilation cannula or an intravenous catheter transtracheally, but the incidence of complications was high. In the same model, we found a 97% success rate for performing an emergency tracheotomy within 4 min with a low rate of complications.