Difficult Facemask Ventilation Research Articles

Nasopharyngeal Ventilation Compared to Facemask Ventilation: A Prospective, Randomized, Crossover Trial in Two Different Elective Cohorts.

Facemask ventilation is routinely used to preoxygenate patients before endotracheal intubation during anesthesia induction or to secure ventilation in patients with respiratory insufficiency. Occasionally, facemask ventilation cannot be performed adequately. The placement of a regular endotracheal tube through the nose into the hypopharynx may be a valid alternative to improve ventilation and oxygenation before endotracheal intubation (nasopharyngeal ventilation). We tested the hypothesis that nasopharyngeal ventilation is superior in its efficacy compared to traditional facemask ventilation. In this prospective, randomized, crossover trial, we enrolled surgical patients requiring either nasal intubation (cohort #1, n = 20) or patients who met "difficult to mask ventilate" criteria (cohort #2, n = 20). Patients in each cohort were randomly assigned to receive pressure-controlled facemask ventilation followed by nasopharyngeal ventilation or vice versa. The ventilation settings were kept constant. The primary outcome was tidal volume. The secondary outcome was the difficulty of ventilation, measured using the Warters grading scale. Tidal volume was significantly increased by nasopharyngeal ventilation in cohort #1 (597 ± 156 ml vs.462 ± 220 ml, p = 0.019) and cohort #2 (525 ± 157 ml vs.259 ± 151 ml, p < 0.01). Warters grading scale for mask ventilation was 0.6 ± 1.4 in cohort #1, and 2.6 ± 1.5 in cohort #2. Patients at risk for difficult facemask ventilation may benefit from nasopharyngeal ventilation to maintain adequate ventilation and oxygenation before endotracheal intubation. This ventilation mode may offer another option for ventilation at induction of anesthesia and during the management of respiratory insufficiency, especially in the setting of "unexpected" ventilation difficulty.

Difficult or impossible facemask ventilation in children with difficult tracheal intubation: a retrospective analysis of the PeDI registry

BackgroundDifficult facemask ventilation is perilous in children whose tracheas are difficult to intubate. We hypothesised that certain physical characteristics and anaesthetic factors are associated with difficult mask ventilation in paediatric patients who also had difficult tracheal intubation. MethodsWe queried a multicentre registry for children who experienced “difficult” or “impossible” facemask ventilation. Patient and case factors known before mask ventilation attempt were included for consideration in this regularised multivariable regression analysis. Incidence of complications, and frequency and efficacy of rescue placement of a supraglottic airway device were also tabulated. Changes in quality of mask ventilation after injection of a neuromuscular blocking agent were assessed. ResultsThe incidence of difficult mask ventilation was 9% (483 of 5453 patients). Infants and patients having increased weight, being less than 5th percentile in weight for age, or having Treacher-Collins syndrome, glossoptosis, or limited mouth opening were more likely to have difficult mask ventilation. Anaesthetic induction using facemask and opioids was associated with decreased risk of difficult mask ventilation. The incidence of complications was significantly higher in patients with “difficult” mask ventilation than in patients without. Rescue placement of a supraglottic airway improved ventilation in 71% (96 of 135) of cases. Administration of neuromuscular blocking agents was more frequently associated with improvement or no change in quality of ventilation than with worsening. ConclusionsCertain abnormalities on physical examination should increase suspicion of possible difficult facemask ventilation. Rescue use of a supraglottic airway device in children with difficult or impossible mask ventilation should be strongly considered.

PREOPERATIVE SINGLE ANTHROPOMETRIC SCREENING TESTS OF DIFFICULT FACE MASK VENTILATION AND DIFFICULT DIRECT LARYNGOSCOPY INTUBATION IN PATIENTS UNDERGOING OTORHINOLARYNGOLOGICAL SURGERY: A PROSPECTIVE, OBSERVATIONAL, SINGLE CENTER STUDY.

The aim of this study was to assess preoperative airway history data and single anthropometric screening tests of difficult face mask ventilation (FMV) and difficult direct laryngoscopy intubation (DLI) in otorhinolaryngological surgery. Final analysis included 62 patients aged ≥14 years undergoing elective surgery with endotracheal intubation at a single center during a one-month period. Data on difficult intubation history, airway symptoms and pathology related to difficult airway were prospectively collected. Han scoring classification of FMV and Intubation Difficulty Score (IDS) were used. There were 14 (22.6%) patients with a history of current airway tumors or abscesses. Only two (3.2%) patients were preoperatively evaluated as anticipated difficult airway. Both were slightly difficult to ventilate and scored IDS 5 and IDS 8. FMV was graded as easy in 50 (80.5%), slightly difficult in 10 (16.1%) and difficult in 2 (3.2%) cases. There were 29 (46.78%) slightly difficult DLIs and one (1.6%) case of difficult DLI. The study confirmed clinically relevant incidence of difficulties with FMV and DLI in otorhinolaryngologic surgery patients. However, there should be stronger evidence to identify a single preoperative variable predicting difficult airway.

AIRWAY MANAGEMENT GUIDELINES IN OBSTETRICS.

Anatomic and physiologic changes during pregnancy make it more difficult to establish a safe airway in pregnant women in case of the need for surgery under general anesthesia than in the non-obstetric population. The inability to ventilate and oxygenate is one of the most common causes of morbidity and mortality associated with general anesthesia for cesarean section. The aim of this paper is to present and analyze modern guidelines and algorithms for the management of difficult airway in obstetrics as an important segment of anesthesiology practice. Modern difficult airway management guidelines for pregnant women describe the procedure of difficult facemask ventilation, difficult airway management by using supraglottic devices, difficult endotracheal intubation, and emergency cricothyrotomy or tracheotomy in a situation where oxygenation and ventilation are impossible. Algorithms describe the procedures and equipment for each variant of difficult airway and decision-making strategies in situations when neither airway nor adequate oxygenation can be provided. Croatian anesthesiologists in most obstetric departments have appropriate equipment, as well as necessary experience in difficult airway management for pregnant women, and modern algorithms from the most developed countries can be adopted and accommodated to our daily practice, as well as incorporated into the training curricula of residents.

What We Knew and What's New: 10 Years of Managing the Difficult Airway

Committee News| July 2022 What We Knew and What's New: 10 Years of Managing the Difficult Airway Brittany Reardon, MD; Brittany Reardon, MD Search for other works by this author on: This Site PubMed Google Scholar Loren Smith, MD, PhD Loren Smith, MD, PhD Search for other works by this author on: This Site PubMed Google Scholar ASA Monitor July 2022, Vol. 86, 32. https://doi.org/10.1097/01.ASM.0000842076.17065.9f Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share MailTo Twitter LinkedIn Cite Icon Cite Get Permissions Search Site Citation Brittany Reardon, Loren Smith; What We Knew and What's New: 10 Years of Managing the Difficult Airway. ASA Monitor 2022; 86:32 doi: https://doi.org/10.1097/01.ASM.0000842076.17065.9f Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll PublicationsASA Monitor Search Advanced Search Topics: intubation, difficult Airway management is a cornerstone of anesthesiology, particularly management of potentially difficult airways, as anesthesiologists are the foremost experts in this arena. Anesthesiologists are acutely aware of how important it is to recognize a potentially difficult airway before administering sedation or anesthesia in order to avoid adverse events, including extended periods of hypoventilation, hypoxic brain injury, and death. The 2012 ASA Practice Guidelines for Management of the Difficult Airway defined a difficult airway as “the clinical situation in which a conventionally trained anesthesiologist experiences difficulty with face mask ventilation of the upper airway, difficulty with tracheal intubation, or both” (Anesthesiology 2013;118:251-70). These practice guidelines divided difficult airways into five categories: difficult facemask or supraglottic airway ventilation, difficult supraglottic airway placement, difficult laryngoscopy, difficult tracheal intubation, and failed intubation. Given the elevated risk of failed ventilation and/or intubation after induction of anesthesia in a suspected or known difficult airway,... You do not currently have access to this content.

The Prevalence of Difficult Airway in Children With Beckwith-Wiedemann Syndrome: A Retrospective Cohort Study.

Beckwith-Wiedemann syndrome (BWS) is the most common congenital overgrowth disorder with an incidence of approximately 1 in 10,000 live births. The condition is characterized by lateralized overgrowth, abdominal wall defects, macroglossia, and predisposition to malignancy. Historically, children with BWS have been presumed to have difficult airways; however, most of the evidence to support this has been anecdotal and derived from case reports. Our study aimed to determine the prevalence of difficult airway in patients with BWS. We hypothesized that most patients with BWS would not have difficult airways. We retrospectively reviewed the electronic medical records of patients enrolled in our institution's BWS registry. Patients with a molecular diagnosis of BWS who were anesthetized between January 2012 and July 2019 were included for analysis. The primary outcome was the presence of difficult airway, defined as difficult facemask ventilation, difficult intubation, or both. We defined difficult intubation as the need for 3 or more tracheal intubation attempts and the need for advanced airway techniques (nondirect laryngoscopy) to perform tracheal intubation or a Cormack and Lehane grade ≥3 during direct laryngoscopy. Secondary objectives were to define predictors of difficult intubation and difficult facemask ventilation, and the prevalence of adverse airway events. Generalized linear mixed-effect models were used to account for multiple anesthesia events per patient. Of 201 BWS patients enrolled in the registry, 60% (n = 122) had one or more documented anesthetics, for a total of 310 anesthetics. A preexisting airway was present in 22 anesthetics. The prevalence of difficult airway was 5.3% (95% confidence interval [CI], 3.0-9.3; 18 of 288) of the cases. The prevalence of difficult intubation was 5.2% (95% CI, 2.9-9.4; 12 of 226). The prevalence of difficult facemask ventilation was 2.9% (95% CI, 1.4-6.2; 12 of 277), and facemask ventilation was not attempted in 42 anesthetics. Age <1 year, macroglossia, lower weight, endocrine comorbidities, plastics/craniofacial surgery, tongue reduction surgery, and obstructive sleep apnea were associated with difficult airways in cases without a preexisting airway. About 83.8% (95% CI, 77.6-88.5) of the cases were intubated with a single attempt. Hypoxemia was the most common adverse event. The prevalence of difficult tracheal intubation and difficult facemask ventilation in children with BWS was 5.2% and 2.9%, respectively. We identified factors associated with difficult airway, which included age <1 year, macroglossia, endocrine abnormalities, plastics/craniofacial surgery, tongue reduction surgery, and obstructive sleep apnea. Clinicians should anticipate difficult airways in patients with these factors.

The DIFFMASK score for predicting difficult facemask ventilation: a cohort study of 46,804 patients.

Facemask ventilation is an essential part of airway management. Correctly predicting difficulties in facemask ventilation may reduce the risk of morbidity and mortality among patients at risk. We aimed to develop and evaluate a weighted risk score for predicting difficult facemask ventilation during anaesthesia. We analysed a cohort of 46,804 adult patients who were assessed pre-operatively airway for 13 predictors of difficult airway management and subsequently underwent facemask ventilation during general anaesthesia. We developed the Difficult Facemask (DIFFMASK) score in two consecutive steps: first, a multivariate regression analysis was performed; and second, the regression coefficients of the adjusted regression model were converted into a clinically applicable weighted point score. The predictive accuracy of the DIFFMASK score was evaluated by assessment of receiver operating characteristic curves. The prevalence of difficult facemask ventilation was 1.06% (95%CI 0.97-1.16). Following conversion of regression coefficients into 0, 1, 2 or 3 points, the cumulated DIFFMASK score ranged from 0 to 18 points and the area under the receiver operating characteristic curve was 0.82. The Youden index indicated a sum score ≥5 as an optimal cut-off value for prediction of difficult facemask ventilation giving a sensitivity of 85% and specificity of 59%. The DIFFMASK score indicated that a score of 6-10 points represents a population of patients who may require heightened attention when facemask ventilation is planned, compared with those patients who are obviously at a high- or low risk of difficulties. The DIFFMASK score may be useful in a clinical context but external, prospective validation is needed.

Bedside tests for predicting difficult airways: an abridged Cochrane diagnostic test accuracy systematic review.

Although bedside screening tests are routinely used to identify people at high risk of having a difficult airway, their clinical utility is unclear. We estimated the diagnostic accuracy of commonly used bedside examination tests for assessing the airway in adult patients without apparent anatomical abnormalities scheduled to undergo general anaesthesia. We searched for studies that reported our pre-specified bedside index screening tests against a reference standard, published in any language, from date of inception to 16 December 2016, in seven bibliographic databases. We included 133 studies (127 cohort type and 6 case-control) involving 844,206 participants. Overall, their methodological quality (according to QUADAS-2, a standard tool for assessing quality of diagnostic accuracy studies) was moderate to high. Our pre-specified tests were: the Mallampati test (6 studies); modified Mallampati test (105 studies); Wilson risk score (6 studies); thyromental distance (52 studies); sternomental distance (18 studies); mouth opening test (34 studies); and the upper lip bite test (30 studies). Difficult facemask ventilation, difficult laryngoscopy, difficult intubation and failed intubation were the reference standards in seven, 92, 50 and two studies, respectively. Across all reference standards, we found all index tests had relatively low sensitivities, with high variability, but specificities were consistently and markedly higher than sensitivities. For difficult laryngoscopy, the sensitivity and specificity (95%CI) of the upper lip bite test were 0.67 (0.45-0.83) and 0.92 (0.86-0.95), respectively; upper lip bite test sensitivity (95%CI) was significantly higher than that for the mouth opening test (0.22, 0.13-0.33; p<0.001). For difficult tracheal intubation, the modified Mallampati test had a significantly higher sensitivity (95%CI) at 0.51 (0.40-0.61) compared with mouth opening (0.27, 0.16-0.41; p<0.001) and thyromental distance (0.24, 0.12-0.43; p<0.001). Although the upper lip bite test showed the most favourable diagnostic test accuracy properties, none of the common bedside screening tests is well suited for detecting unanticipated difficult airways, as many of them are missed.

Supraglottic airway devices in difficult airway management: a retrospective cohort study of 658,104 general anaesthetics registered in the Danish Anaesthesia Database.

Indications for using supraglottic airway devices have widened over time and they now hold a prominent role in guidelines for difficult airway management. We aimed to describe the use of supraglottic airway devices in difficult airway management. We included adult patients undergoing general anaesthesia registered in the Danish Anaesthesia Database from 2008 to 2012 whose airway management had been recorded as difficult, defined as: ≥3 tracheal intubation attempts; failed tracheal intubation; or difficult facemask ventilation. In the Danish Anaesthesia Database, a separate difficult airway management module requires the technique used in each successive airway management attempt to be recorded. The primary aim of the study was to describe the use of supraglottic airway devices in cases of difficult airway management. Secondary aims were to examine success rates of supraglottic airway devices in difficult airway management cases, and specifically in the cases of 'cannot intubate, cannot facemask ventilate'. Difficult airway management occurred in 4898 (0.74% (95%CI 0.72-0.76%)) of 658,104 records of general anaesthesia. Supraglottic airway devices were used or use was attempted in 607 cases of difficult airway management (12.4% (95%CI 11.5-13.3%)), and were successful in 395 (65.1% (95%CI 61.2-68.8%)) cases. In 'cannot intubate, cannot facemask ventilate' situations, supraglottic airway devices were used in 86 (18.9% (95%CI 15.6-22.8%)) of 455 records and were successful in 54 (62.8% (95%CI 52.2-72.3%)) cases. We found that supraglottic airway devices are not widely used in the management of the difficult airway despite their prominent role in difficult airway management guidelines.

Преоксигенация: можно ли сделать меру безопасности менее опасной?

While providing reserve time for dificult airway management, preoxygenation with pure oxygen increases the risk of pulmonary complications due to absorption atelectases. The authors explored when it could be appropriate to prevent atelectases by preoxygenation with decreased FiO₂. ASA I-II elective gynecological surgery patients were randomized among five groups (n = 22 each) with preoxygenation using FiO₂ 100, 70, 60, 60% + PEEP 5 mbar and 50%. Even FiO₂ 70% led to decrease. in safe apnea time (i.e. time interval to Sp²O₂ 95%) by two, while FiO₂ 50% - by more than three times. Furthermore, in five similar additional groups of women with same techniques ofpreoxygenation (n = 10 each) it was shown that for FiO₂ 5 70% very fast pattern of SpO2 fall after the first change ofpulseoxymeter figure (100% by 99%) is typical: interval to SpO2 90% was less than 1 min, while for FiO₂ 100% it lasts for 200 s. Since critical problem is "Cannot intubate, cannot ventilate", the authors tried to focus on the difficultfacemask ventilation prognosis. In the group of 71 elective general surgery patients (31 males, 40 females, ASA I-III) original prognostic model based on seven simple bedside tests (removable dentures, beard, snoring, Mallampati class 2-4, age > 50 y.o., BM > 30 kg/m², sternomental distance < 12 cm) demonstrated the reliability of difficult facemask ventilation negative prognosis of 97,5%. The authors suggest that only in patients with reliable prognosis of easy facemask ventilation prevention ofpulmonary complications by preoxygenation with FiO₂ 50-60% could be safely recommended.

Predicted impossible mask ventilation in a patient with giant rhinophyma

SummaryWe describe the safe management of a patient with a giant rhinophyma requiring surgical debulking of the nasal tumour. Anaesthetic management incorporated an awake fibreoptic intubation (AFOI) as an effective facemask seal, and therefore bag/valve/mask ventilation, was predicted to be unachievable. We suggest that this is the safest approach to maintain oxygenation when difficult facemask ventilation is anticipated post anaesthetic induction.

Cervical vertebral hyperostosis and difficult direct laryngoscopy in a patient for primary thyroplasty

SummaryDiffuse idiopathic skeletal hyperostosis is a disease typified by calcification of ligamentous structures, predominantly in the spine. In the cervical spine, large congruous osteophyte formation anterior to the vertebral bodies can cause significant changes to airway anatomy. Difficult facemask ventilation, direct laryngoscopy and LMA positioning have all been reported. Primary thyroplasty involves medialisation of an immobile vocal cord in order to improve voice production. An unobstructed view of the vocal cords is important to aid implant insertion but can complicate airway management. We present the case of an elderly patient undergoing primary thyroplasty with cervical vertebral hyperostosis, dysphagia, immobile vocal cord and difficult direct laryngoscopy. This case highlights the intricacies involved when anaesthetising a patient for complex vocal cord surgery with abnormal airway anatomy.

Use of Simple Clinical Predictors on Preoperative Diagnosis of Difficult Endotracheal Intubation in Obese Patients

Background and objectivesAlthough the incidence of difficult laryngoscopy is similar in obese and non-obese patients, there are more reports of difficult intubation in obese individuals. Alternatives for the diagnosis and prediction of difficult intubation in the preoperative period may help reduce anesthetic complications in obese patients. The aim of this study was to identify predictors for the diagnosis of difficult airway in obese patients, correlating with the clinical methods of pre-anesthetic evaluation and polysomnography. We also compared the incidence of difficult facemask ventilation and difficult laryngoscopy between obese and non-obese patients, identifying the most prevalent predictors. MethodsObservational, prospective and comparative study, with 88 adult patients undergoing general anesthesia. In the preoperative period, we evaluated a questionnaire on the clinical predictors of the obstructive sleep apnea syndrome (OSAS) and anatomical parameters. During anesthesia, we evaluated difficult facemask ventilation and laryngoscopy. Descriptive statistics and correlation test were used for analysis. ResultsPatients were allocated into two groups: obese group (n=43) and non-obese group (n=45). Physical status, prevalence of snoring, hypertension, diabetes mellitus, neck circumference, and Mallampati index were higher in the obese group. Obese patients had a higher incidence of difficult facemask ventilation and laryngoscopy. There was no correlation between anatomical or clinical variable and difficult facemask ventilation in both groups. In obese patients, the diagnosis of OSAS showed strong correlation with difficult laryngoscopy. ConclusionsThe clinical and polysomnographic diagnosis of OSA proved useful in the preoperative diagnosis of difficult laryngoscopy. Obese patients are more prone to difficult facemask ventilation and laryngoscopy.

Use of Simple Clinical Predictors on Preoperative Diagnosis of Difficult Endotracheal Intubation in Obese Patients

Background and objectivesAlthough the incidence of difficult laryngoscopy is similar in obese and non-obese patients, there are more reports of difficult intubation in obese individuals. Alternatives for the diagnosis and prediction of difficult intubation in the preoperative period may help reduce anesthetic complications in obese patients. The aim of this study was to identify predictors for the diagnosis of difficult airway in obese patients, correlating with the clinical methods of pre-anesthetic evaluation and polysomnography. We also compared the incidence of difficult facemask ventilation and difficult laryngoscopy between obese and non-obese patients, identifying the most prevalent predictors. MethodsObservational, prospective and comparative study, with 88 adult patients undergoing general anesthesia. In the preoperative period, we evaluated a questionnaire on the clinical predictors of the obstructive sleep apnea syndrome (OSAS) and anatomical parameters. During anesthesia, we evaluated difficult facemask ventilation and laryngoscopy. Descriptive statistics and correlation test were used for analysis. ResultsPatients were allocated into two groups: obese group (n = 43) and non-obese group (n = 45). Physical status, prevalence of snoring, hypertension, diabetes mellitus, neck circumference, and Mallampati index were higher in the obese group. Obese patients had a higher incidence of difficult facemask ventilation and laryngoscopy. There was no correlation between anatomical or clinical variable and difficult facemask ventilation in both groups. In obese patients, the diagnosis of OSAS showed strong correlation with difficult laryngoscopy. ConclusionsThe clinical and polysomnographic diagnosis of OSA proved useful in the preoperative diagnosis of difficult laryngoscopy. Obese patients are more prone to difficult facemask ventilation and laryngoscopy.

Rapid-sequence induction of anesthesia in obstetric women: how safe is it?

A cautionary tale…A 35-year-old woman, 154 cm, 86 kg, with placentaprevia and preeclampsia, had massive bleeding afterconsuming a lunch. She was immediately transferredto the operating room, where an anesthesiologist wascalled in. She was morbidly obese, having largebreasts and a low-pitched voice (indicative of lar-yngeal edema), and the view of the oropharynx wasobscured (Mallampati score 4). Awake trachealintubation was attempted, but the patient refused toopen her mouth. General anesthesia was induced as arapid sequence, and tracheal intubation was attemp-ted, but failed twice. A senior anesthesiologist wascalled in and accomplished intubation. Cesareansection was started. Soon after this, it was found thatthe tube was wrongly inserted into the esophagus.The tube was taken out and mask ventilation wasattempted, but this was difficult. Arterial hemoglobinoxygen saturation rapidly decreased to 70 % withcardiac arrhythmia. Nevertheless, the baby was suc-cessfully taken out and the mother started to breathe.As the operation would continue, the laryngeal maskairway was inserted. The mother vomited andaspirated.This is a fiction, but we all might have heard about a realstory like this. And, what was wrong with this case? Whycannot we clearly answer what should have been done tothis case?In this issue of the Journal, Tao et al. [1] report a ret-rospective analysis of pregnant women who underwentgeneral anesthesia during 2001–2006 in a teaching hospi-tal, to obtain the incidence of ‘difficult airway,’ which wasdefined as follows: necessity of three or more attempts atdirect laryngoscopy, the use of any maneuvers or tech-niques outside the rapid sequence induction routine(including mask ventilation resulting from oxygen desatu-ration from unsuccessful intubation attempts), the use ofadditional airway equipment, or inability to intubate thetrachea. The incidence was 0.56 % (12 of 2,158 patients).They state that tracheal intubation was possible in morethan 99.9 % of pregnant patients, and the incidence ofdifficult airway in pregnant patients is no higher than theincidence in nonpregnant patients. They attempted to seekfactors contributing to the difficult airway, and have foundthat the lack of experience of anesthesia providersincreased the incidence, whereas emergency cesareansection did not add another level of difficulty over plannedcesarean section [1].So, can we conclude that tracheal intubation in pregnantwomen is as easy as in nonpregnant patients? The reportedincidence in the general population of difficult trachealintubation is about 1 %, and that for difficult facemaskventilation is as much as 5 % [2–4]. Therefore, it seemsreasonable to conclude that the incidence in pregnantpatients may be similar to, or not much higher than, theincidence in the general population.Can we then state that the pregnant patients are not atincreased risk of serious airway complications duringanesthesia? To answer this question, we need to know therisk in the general population. Until recently, the incidence,consequences, and causes of the problems had not been that

Supraglottic airways in difficult airway management: successes, failures, use and misuse

Supraglottic airway devices (SAD) play an important role in the management of patients with difficult airways. Unlike other alternatives to standard tracheal intubation, e.g. videolaryngoscopy or intubation stylets, they enable ventilation even in patients with difficult facemask ventilation and simultaneous use as a conduit for tracheal intubation. Insertion is usually atraumatic, their use is familiar from elective anaesthesia, and compared with tracheal intubation is easier to learn for users with limited experienced in airway management. Use of SADs during difficult airway management is widely recommended in many guidelines for the operating room and in the pre-hospital setting. Despite numerous studies comparing different SADs in manikins, there are few randomised controlled trials comparing different SADs in patients with difficult airways. Therefore, most safety data come from extended use rather than high quality evidence and claims of efficacy and particularly safety must be interpreted cautiously.