Size matters: choosing the right tracheal tube

Executive Summary of the Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR) Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management

The Airway section of the Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) present the Guidelines for the integral management of difficult airway in adult patients. This document provides recommendations based on current scientific evidence, theoretical-educational tools and implementation tools, mainly cognitive aids, applicable to the treatment of the airway in the field of anesthesiology, critical care, emergencies and prehospital medicine. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations and optimization in the progression of the application of strategies to preserve adequate alveolar oxygenation in order to improve safety and quality of care.

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part II

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Evolving Endotracheal Tube Preferences and Practices: Intensivist Knowledge Gaps and Sex Disparities

OBJECTIVES

The complex management of intubation-related laryngeal injury makes prevention vital. The purpose of this study is to assess endotracheal tube (ETT) practices and preferences among intensivists at our institution.

METHODS

Chart review of intubated patients and intensivist survey were simultaneously performed in January 2016 and August 2022. A height-to-ETT size ratio (H:ETT) was calculated for each patient in the 2022 cohort. Intubated patients were followed until tracheostomy, extubation, or death occurred. Surveys assessed intensivist preferences for ETT size and management of intubated patients.

RESULTS

300 ICU patients were included. The mean ETT size for males decreased from 7.73 ± 0.30 in 2016 to 7.57 ± 0.25 in 2022 (p < 0.001). The average H:ETT of men was higher than females (p = 0.004), indicating that females in this population were intubated with larger ETTs relative to their height compared to males. Whereas the majority (66.7%) of intensivists endorse 7.0 ETTs as the standard for women, the majority (70%) of women at our institution are intubated with a 7.5 ETT or larger. Of intubated patients in the ICU, 23 (19.5%) were intubated for 11 days or longer.

CONCLUSIONS

Compared to men, women are intubated with larger-than-preferred ETTs relative to height. Additionally, patients in our study were intubated for longer than preferred based on intensivist surveys, putting this population at higher risk for acute laryngeal injury (AlgI)-related laryngotracheal stenosis (LTS). Further studies should seek to identify similar trends and barriers to reducing ALgI-related LTS.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:3080-3086, 2023.

A Neural Integrity Monitor Electromyography Endotracheal Tube Causes More Severe Postoperative Sore Throat Than a Standard Endotracheal Tube in Adults: A Prospective Cohort Study

BACKGROUND

This study aimed at figuring out the different effects of a neural integrity monitor electromyography endotracheal tube (NIM-EMG-ETT) and a standard endotracheal tube (ETT) on postoperative sore throat (POST).

METHODS

This prospective cohort study enrolled 143 patients scheduled to undergo general anesthesia with endotracheal intubation. Patients were allocated into three groups: Group A, non-thyroid surgery with a standard ETT; Group B, thyroid surgery with a standard ETT; Group C, thyroid surgery with a NIM-EMG-ETT. The incidence, the severity and visual analog scale (VAS) of POST were recorded. The incidence and the severity of POST were tested by χ2 test or Fisher's exact test. And VAS of POST was tested by Kruskal-Wallis test.

RESULTS

The incidences of POST in Group B and Group C were significantly higher than that of Group A at all the time points after extubation (P < 0.001). The incidences of POST in Group C was significantly higher than that in Group B at 8 h, 24 h and 48 h after extubation (89.4% vs. 68.8%, P = 0.014, relative risk (RR) 1.30, 95% confidence interval (CI) 1.05-1.61; 89.4% vs. 58.3%, P = 0.001, RR 1.53, 95% CI 1.18-1.98; 76.6% vs. 45.8%, P = 0.002, RR 1.67, 95% CI 1.18-2.36). Moreover, there was a significant higher VAS of POST and more serious POST with Group C than with Group B.

CONCLUSIONS

A NIM-EMG-ETT may induce higher incidence of POST and more serious POST than a standard ETT.

TRAIL REGISTRATION

Chinese Clinical Trail Registry ( http://www.chictr.org.cn/index.aspx , ChiCTR2200058896, 2022-4-18).

High prevalence of postoperative arytenoid dislocation in patients undergoing liver transplantation: A case-control study

Arytenoid dislocation (AD) is a rare complication of surgery under general anesthesia. The potential factors for AD remain poorly defined, and the identification of risk factors is beneficial for reducing its incidence. We found that patients undergoing liver transplantation appeared to be more susceptible to postoperative AD at our hospital. The present study was designed to clarify this issue. A retrospective hospital-based case-control study was conducted in patients undergoing surgery under general anesthesia between 2017 and 2021. Recorded data for all patients were age, sex, body weight, height, body mass index, position of patients during surgery, duration of surgery, emergency status of surgery, and liver transplantation. Logistic regression analysis was performed to determine risk factors for AD. Thirty thousand one hundred fifty-four patients who underwent general anesthesia between 2017 and 2021 were included. Sixteen (0.05%) patients were diagnosed with AD, including 10 (3.9%) patients among 259 patients who underwent liver transplantation and 6 patients had complications among the 29,895 patients who underwent other operations (P < .0001). Postoperative AD incidence was significantly elevated in patients undergoing liver transplantation. This finding should be clinically relevant and alarming for anesthesiologists and clinicians to help avoid arytenoid dislocation and improve patient outcomes. Further studies that incorporate detailed data are needed to determine risk factors for AD.

Penetrating Neck Injury: Double Jeopardy of a Complex Aerodigestive Dilemma

The neck is a critical region containing many essential structures. Before surgical intervention, it is crucial to assess the adequacy of the airway and circulation, as well as the presence of any skeletal or neurological damage. Here, we present a case of a 33-year-old male with a background of amphetamine abuse who presented to our emergency department with a penetrating neck injury just below the mandible at the hypopharynx level, resulting in an upper zone II neck injury with complete separation of the airway. The patient was taken immediately to the operating room for exploration. Airways were managed by direct intubation, hemostasis was maintained, and the open laryngeal injury was repaired. After the surgery, this patient was transferred to the intensive care unit for two days and discharged after a satisfactory full recovery. Penetrating neck injuries are rare but often fatal. Advanced trauma life support guidelines emphasize the importance of managing the airway as the first action. Providing multidisciplinary care before, during, and after trauma can help prevent and treat such incidents.

Clinicodemographic Predictors of Tracheotomy Tube Size and Decannulation: A Multiinstitutional Retrospective Cohort Study on Tracheotomy

OBJECTIVE

We aimed to discern clinico-demographic predictors of large (≥8) tracheostomy tube size placement, and, secondarily, to assess the effect of large tracheostomy tube size and other parameters on odds of decannulation before hospital discharge.

SUMMARY OF BACKGROUND DATA

Factors determining choice of tracheostomy tube size are not well-characterized in the current literature, despite evidence linking large tracheostomy tube size with posttracheotomy tracheal stenosis. The effect of tracheostomy tube size on timing of decannulation is also unknown, an important consideration given reported associations between endotracheal tube size and probability of failed extubation.

METHODS

We collected information pertaining to patients who underwent tracheotomy at 1 of 10 U.S. health care institutions between 2010 and 2019. Tracheostomy tube size was dichotomized (≥8 and <8). Multivariable logistic regression models were fit to identify predictors of (1) large tracheostomy tube size, and (2) decannulation before hospital discharge.

RESULTS

The study included 5307 patients, including 2797 (52.7%) in the large tracheostomy cohort. Patient height (odds ratio [OR] = 1.060 per inch; 95% confidence interval [CI] 1.041-1.070) and obesity (1.37; 95% CI 1.1891.579) were associated with greater odds of large tracheostomy tube; otolaryngology performing the tracheotomy was associated with significantly lower odds of large tracheostomy tube (OR = 0.155; 95% CI 0.131-0.184). Large tracheostomy tube size (OR = 1.036; 95% CI 0.885-1.213) did not affect odds of decannulation.

CONCLUSIONS

Obesity was linked with increased likelihood of large tracheostomy tube size, independent of patient height. Probability of decannulation before hospital discharge is influenced by multiple patient-centric factors, but not by size of tracheostomy tube.

A Soft Robotic Balloon Endoscope for Airway Procedures

Soft robots can provide advantages for medical interventions given their low cost and their ability to change shape and safely apply forces to tissue. This article explores the potential for their use for endoscopically-guided balloon dilation procedures in the airways. A scalable robot design based on balloon catheter technology is proposed, which is composed of five balloons together with a tip-mounted camera and LED. Its design parameters are optimized with respect to the clinical requirements associated with balloon dilation procedures in the trachea and bronchi. Possessing a lumen to allow for respiration and powered by the pressure and vacuum sources found in a clinical procedure room, the robot is teleoperated through the airways using a game controller and real-time video from the tip-mounted camera. The robot design includes proximal and distal bracing balloons that expand radially to produce traction forces. The distal bracing balloon is also used to perform balloon dilation. Three actuation balloons, located between the bracing balloons, produce elongation and bending of the robot body to enable locomotion and turning. An analysis of the actuation balloons, which incorporate helical coils to prevent radial collapse, provides design formulas by relating geometric parameters to such performance criteria as maximum change in actuator length and maximum robot bending angle. Experimental evaluation of a prototype robot inside rigid plastic tubes and ex vivo porcine airways is used to demonstrate the potential of the approach.

Quantitative Measurement of Throat and Larynx After Endotracheal Intubation for Palatoplasty

Introduction

Quantitative morphometric measurements of living human upper airway remain challenging. This study aimed to introduce a special laser projection device that can facilitate computer-assisted, digitalized analysis and provide important information on airway mucosa change, before and after endotracheal intubation for palatoplasty.

Materials and Methods

The laryngeal images were captured before and after surgery. Image processing techniques were used to quantize the post-operative laryngeal variation, with its distinct color space and texture features. Meanwhile, the maximum length of the vocal fold, vocal width at the midpoint, maximum cross-sectional area of the glottic space, maximum cross-sectional area of the oropharyngeal inlet (CSAOI) and the depth of the retropalatal space were determined and calculated. These parameters were analyzed and compared before and after surgery.

Results

A total of 39 subjects were enrolled in this study. The color space and texture analysis all show trends toward higher measures in post-operative images than in pre-operative images, especially in the interarytenoid region. Furthermore, the glottic area showed a significant decrease of 31.2%, while the vocal width showed a significant increase after intubation. The post-operative retropalatal depth and CSAOI were significantly deeper and larger than the baseline, reaching their peak in the 4th week after the surgery, and then slightly reduced in the 12th week.

Conclusion

For the first time we present a series of changes in upper airway after surgery, by using a laser module with quantitative measurement. Our equipment and processing can measure subtle mucosal changes that would allow a clinician to diagnose post-operative airway inflammation in a simpler and less invasive way. Here additional information collected by different imaging modalities would help to solve multiple current unmet needs in post-operative airway inflammation.

Non-cardiac Manifestations in Adult Patients With Mucopolysaccharidosis

Mucopolysaccharidoses (MPS) are a heterogeneous group of disorders that results in the absence or deficiency of lysosomal enzymes, leading to an inappropriate storage of glycosaminoglycans (GAGs) in various tissues of the body such as bones, cartilage, heart valves, arteries, upper airways, cornea, teeth, liver and nervous system. Clinical manifestations can become progressively exacerbated with age and affect their quality of life. Developments in advanced supportive treatment options such as enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT) may have improved patients' life span. Adult MPS patients require specialist clinical surveillance long-term. In many cases, in addition to the MPS-related health problems, they may develop age-related complications. Considering the complexity of their clinical manifestations and lack of guidelines on the management of adult MPS disorders, multispecialty and multidisciplinary teams' care is essential to diagnose and treat health problems that are likely to be encountered. This review presents non-cardiac clinical manifestations, their pathophysiology, management and long-term outcomes in adult MPS patients.

How Does Tube Size Affect Patients' Experiences of Postoperative Sore Throat and Hoarseness? A Randomised Controlled Blinded Study

Sore throat (POST) and hoarseness (PH) are common complaints after endotracheal intubation (EI). The aim of this study was to investigate whether tube size impacts the experiences of POST and PH after EI in patients undergoing elective surgery, as well as to document a possible role of gender. This randomised, controlled, blinded study was conducted at Aalborg University Hospital, Thisted, Denmark or North Denmark Regional Hospital, Denmark. A total of 236 patients (53.4% female, mean age 50.9 years (SD 14.0)) were enrolled from the departments of gynaecology, parenchyma and orthopaedics. The patients were randomised to a tube size of 8.0 or 7.0 for males and 7.0 or 6.0 for females. Tube sizes were known to the anaesthesia staff but blinded for patients, researchers and staff at the postoperative care unit. POST and/or PH was reported 30–60 min before anaesthesia, at 30 min and at 2, 5, 12, 24, 48, 72 and 96 h after anaesthesia. Both female and male patients experienced significantly lower levels of POST and PH after intubation with the smallest tube size. This study demonstrates that a smaller size of tube results in a reduction in POST and PH after EI for both male and female patients.

Comparing tracheostomy techniques: Bjork flap vs. tracheal window

OBJECTIVES

Various operative techniques are used to perform tracheostomies. The objective of this study was to evaluate patient factors that influence the decision to perform a Bjork flap or a window.

METHODS

A retrospective review was conducted of all patients who underwent tracheostomies from January 2015 to December 2019 at a tertiary care medical center. All patients underwent tracheostomy with either a Bjork flap or a window. Charts were reviewed for demographics, comorbidities, indication for tracheostomy, operative details, and complications.

RESULTS

A total of 217 tracheostomies were evaluated, of which 104 (47.9%) had a Bjork flap and 113 (52.1%) had a window. Bjork flap was significantly more likely to be performed in patients with a higher average body mass index (p = 0.05), requiring ventilatory support (p = 0.0001), or had a stroke (p = 0.0140). A window was used significantly more in patients with prior neck dissection (p = 0.0110) or neck radiation (p < 0.0001). No significant difference was observed for post-op bleeding, returning to the operating room, or days to decannulation. In all tracheostomies, thrombocytopenia was found to significantly correlate with post-op bleeding (p = 0.0006), while blood thinner use did not.

CONCLUSION

Bjork flaps were more likely to be performed in those with a history of prolonged mechanical ventilation and elevated body mass index. Windows were performed more frequently in patients with a head and neck cancer history. Future prospective studies are needed to compare the outcomes of these techniques and their impacts on the trachea long term.

Equipment and procedural setup for interventional pulmonology procedures in the intensive care unit

Procedural setup is an important aspect of any procedure. Interventional pulmonologists provide a procedural practice and have additional expertise in performing high-risk procedures needed in the critically ill patients in intensive care. Taking the time to plan the procedure setup in advance and having all necessary equipment readily available at the patient's bedside is imperative for procedural services. This is especially essential to ensure patient safety, minimize risk of complications, and improve success for specialized procedures performed by interventional pulmonary in the intensive care unit. In this review we describe the equipment and procedural setup ideal for both pleural and airway procedures. These include flexible diagnostic and therapeutic bronchoscopy, ultrasound guided thoracentesis, chest tube insertion, difficult airway management, and bedside percutaneous dilatation tracheostomy. We provide a guide checklist for these procedures emphasizing the practical aspects of each procedure from selecting the appropriate size endotracheal tube to operator positioning to ensure efficiency and best access. The components of procedural setup are discussed in relation to patient factors that include patient positioning and anesthesia, personnel in the procedure team and the equipment itself. We further briefly describe the additional equipment needed for specialized techniques in therapeutic bronchoscopy used by interventional pulmonologists.

Endotracheal Tubes Design: The Role of Tube Bending

Endotracheal tubes (ETT) passed inside the human trachea witness tube bending at different angles, affecting the local fluid flow dynamics. This induces a variable mechanical ventilation performance across patients’ comfortability levels. Our understanding of the local fluid flow dynamics phenomena is thus crucial to enhance the maneuverability of ETT under operation. For the first time to our knowledge, we shed light on ETT through computational fluid dynamics (CFD) to investigate the bending effect of ETT on the local airflow in volume-controlled mechanical ventilation. We considered an ETT with 180° arc bend configuration, including Murphy’s eye. We identified several flow phenomena associated with the bending, such as flow asymmetries, secondary flows, and vortex dynamics throughout the tube.

Characteristics of a New Device for Intubation Through a Laryngeal Mask Airway Over a Flexible Endoscope

The laryngeal mask airway (LMA) is widely used for airway management in the emergency and elective treatment of patients in both the in-hospital and prehospital setting. The rate of prehospital use is increasing. The LMA is a vital link in the vortex approach to managing a difficult airway. Clinicians will be increasingly faced with the dilemma of managing the patient who has an LMA in place, but still requires the airway secured by an endotracheal tube (ETT). Flexible endoscopic intubation through an LMA is a simpler procedure than awake flexible endoscopic intubation. Furthermore, intubating flexible endoscopes are increasingly available and affordable (now single use) making its use out of the domains of the operating theater and intensive care unit feasible. The authors aim to inform clinicians about the indications, physical characteristics, and insertion/removal techniques related to a new device, the Rescue™ ETT (Genesis Airway Innovations®, Sunshine Coast, Australia), designed specifically for intubation through an LMA over a flexible endoscope and compare them to current devices used for this purpose.

The Association Between Endotracheal Tube Size and Aspiration (During Flexible Endoscopic Evaluation of Swallowing) in Acute Respiratory Failure Survivors

OBJECTIVES

To determine whether a modifiable risk factor, endotracheal tube size, is associated with the diagnosis of postextubation aspiration in survivors of acute respiratory failure.

DESIGN

Prospective cohort study.

SETTING

ICUs at four academic tertiary care medical centers.

PATIENTS

Two hundred ten patients who were at least 18 years old, admitted to an ICU, and mechanically ventilated with an endotracheal tube for longer than 48 hours were enrolled.

INTERVENTIONS

Within 72 hours of extubation, all patients received a flexible endoscopic evaluation of swallowing examination that entailed administration of ice, thin liquid, thick liquid, puree, and cracker boluses. Patient demographics, treatment variables, and hospital outcomes were abstracted from the patient's medical records. Endotracheal tube size was independently selected by the patient's treating physicians.

MEASUREMENTS AND MAIN RESULTS

For each flexible endoscopic evaluation of swallowing examination, laryngeal pathology was evaluated, and for each bolus, a Penetration Aspiration Scale score was assigned. Aspiration (Penetration Aspiration Scale score ≥ 6) was further categorized into nonsilent aspiration (Penetration Aspiration Scale score = 6 or 7) and silent aspiration (Penetration Aspiration Scale score = 8). One third of patients (n = 68) aspirated (Penetration Aspiration Scale score ≥ 6) on at least one bolus, 13.6% (n = 29) exhibited silent aspiration, and 23.8% (n = 50) exhibited nonsilent aspiration. In a multivariable analysis, endotracheal tube size (≤ 7.5 vs ≥ 8.0) was significantly associated with patients exhibiting any aspiration (Penetration Aspiration Scale score ≥ 6) (p = 0.016; odds ratio = 2.17; 95% CI 1.14-4.13) and with risk of developing laryngeal granulation tissue (p = 0.02).

CONCLUSIONS

Larger endotracheal tube size was associated with increased risk of aspiration and laryngeal granulation tissue. Using smaller endotracheal tubes may reduce the risk of postextubation aspiration.

Local Delivery of Mometasone Furoate from an Eluting Endotracheal Tube Reduces Airway Morbidity Following Long-Term Animal Intubation

BACKGROUND

upper airway complications are common sequelae of endotracheal tube (ETT) intubation, and systemic corticosteroids are considered a mainstay treatment for this problem. Drug-eluting ETT may present an attractive option for topical steroid delivery while avoiding systemic side effects and improving the therapeutic outcome. The objective of the present study is to evaluate the reduction of tube-related tracheal morbidity via a self-designed steroid-eluting ETT with controlled sustained release properties in an animal model.

METHODS

steroid-eluting ETTs were coated by poly(lactic-co-glycolic acid) -electrospun nanofibers loaded with mometasone furoate (MF) as a model drug. Animals were randomly assigned into three equal groups: non-intubated, blank-ETT, and loaded-ETT. The intubation interval was 1 week. Specimens were analyzed by histology, specific fibrosis staining, and scanning electron microscopy (SEM).

RESULTS

the blank-ETT group exhibited a significant increase in tracheal mucosal thickness compared to the loaded-ETT and control groups. Average tracheal mucosal thickness was 112 ± 34, 242 ± 49, and 113 ± 43 μm in the control, blank-ETT, and loaded-ETT groups, respectively. The blank-ETT group exhibited a significant increase in tracheal fibrosis compared to the loaded-ETT and control groups. Relative fibrosis values were 0.07 ± 0.05, 0.154 ± 0.1, and 0.0984 ± 0.084% for the control, blank-ETT, and loaded-ETT groups, respectively. While SEM imaging showed normal surface structures in the control group, intubated blank-ETT rats showed severe surface structural damage, whereas only mild damage was observed in the loaded-ETT group.

CONCLUSIONS

local sustained release of MF via a self-designed drug-eluting ETT is a potential therapeutic approach which may significantly reduce tube-related upper airway morbidity.

Laryngeal Injury and Upper Airway Symptoms After Endotracheal Intubation During Surgery: A Systematic Review and Meta-analysis

Laryngeal injury from intubation can substantially impact airway, voice, and swallowing, thus necessitating multidisciplinary interventions. The goals of this systematic review were (1) to review the types of laryngeal injuries and their patient-reported symptoms and clinical signs resulting from endotracheal intubation in patients intubated for surgeries and (2) to better understand the overall the frequency at which these injuries occur. We conducted a search of 4 online bibliographic databases (ie, PubMed, Embase, Cumulative Index of Nursing and Allied Health Literature [CINAHL], and The Cochrane Library) and ProQuest and Open Access Thesis Dissertations (OPTD) from database inception to September 2019 without restrictions for language. Studies that completed postextubation laryngeal examinations with visualization in adult patients who were endotracheally intubated for surgeries were included. We excluded (1) retrospective studies, (2) case studies, (3) preexisting laryngeal injury/disease, (4) patients with histories of or surgical interventions that risk injury to the recurrent laryngeal nerve, (5) conference abstracts, and (6) patient populations with nonfocal, neurological impairments that may impact voice and swallowing function, thus making it difficult to identify isolated postextubation laryngeal injury. Independent, double-data extraction, and risk of bias assessment followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Cochrane Collaboration's criteria. Twenty-one articles (1 cross-sectional, 3 cohort, 5 case series, 12 randomized controlled trials) representing 21 surgical studies containing 6140 patients met eligibility criteria. The mean patient age across studies reporting age was 49 (95% confidence interval [CI], 45-53) years with a mean intubation duration of 132 (95% CI, 106-159) minutes. Studies reported no injuries in 80% (95% CI, 69-88) of patients. All 21 studies presented on type of injury. Edema was the most frequently reported mild injury, with a prevalence of 9%-84%. Vocal fold hematomas were the most frequently reported moderate injury, with a prevalence of 4% (95% CI, 2-10). Severe injuries that include subluxation of the arytenoids and vocal fold paralysis are rare (<1%) outcomes. The most prevalent patient complaints postextubation were dysphagia (43%), pain (38%), coughing (32%), a sore throat (27%), and hoarseness (27%). Overall, laryngeal injury from short-duration surgical intubation is common and is most often mild. No uniform guidelines for laryngeal assessment postextubation from surgery are available and hoarseness is neither a good indicator of laryngeal injury or dysphagia. Protocolized screening for dysphonia and dysphagia postextubation may lead to improved identification of injury and, therefore, improved patient outcomes and reduced health care utilization.

Comparison of the selection of nasotracheal tube diameter based on the patient's sex or size of the nasal airway: A prospective observational study

When selecting the nasotracheal tube diameter for nasotracheal intubation, atraumatic introduction of the tube through the nasal passage and a safe location of the tube's cuff and tip should be ensured simultaneously. To maintain safety margin for the tube's cuff and tip from the vocal cords and carina (2 cm and 3 cm, respectively), the maximum allowable proximal-cuff-to-tip distance was calculated as 5 cm less than the measured vocal cords-to-carina distance. The primary aim of this study was to find a single predictive preoperative factor of the nostril size and maximum allowable proximal-cuff-to-tip distance of nasotracheal tubes. The secondary aim was to compare the difference in the safety margin between the maximum allowable proximal-cuff-to-tip distance based on the patient's airway and the actual proximal-cuff-to-tip distance of the selected tube. We used fiberoptic bronchoscope to measure the distance from the vocal cords to the carina for the calculation of the maximum allowable proximal-cuff-to-tip distance. We analyzed the association of preoperative characteristics such as age, sex, height, and weight with the nostril size and maximum allowable proximal-cuff-to-tip distance. The proportion of patients with appropriate locations of both the cuff and tip was evaluated. Sex and height were significant predictive factors of the nostril size and maximum allowable proximal-cuff-to-tip distance, respectively (p = 0.0001 and p = 0.0048). The difference in the safety margin was significantly decreased when the tube diameter was selected based on the nostril size rather than by sex (p<0.0001). The proportion of patients who had the appropriate cuff/tip location was significantly larger (75.2%) when the tube diameter was selected by sex compared to when it was selected by the nostril size (65%) (p<0.0001). It is more suitable to select the nasotracheal tube diameter based on sex rather than by nostril size to ensure the safe location of the tube's cuff and tip simultaneously.

Effects of thermal softening of endotracheal tubes on postoperative sore throat: A randomized double-blinded trial

BACKGROUND

Postoperative throat complications after intubation are undesirable but frequent outcomes. A randomized, double-blinded study was performed to determine whether thermal softening of endotracheal tubes reduced throat complications after intubation.

METHODS

Patients (n = 196) undergoing nasal surgery were randomly allocated into the control group and thermal softening groups. Sore throat and hoarseness were evaluated 1 and 24 hours after extubation. The severity of sore throat was evaluated using the numeric rating scale (NRS). The primary outcome was the incidence of sore throat 1 hour after extubation and sore throat was defined as a painful or scratchy feeling in the throat. The secondary outcomes were the incidence of hoarseness 1 hour after extubation, the incidence of sore throat and hoarseness 24 hours after extubation, severity of sore throat, and vocal cord injuries.

RESULTS

The incidence of sore throat 1 hour after extubation was lower in the thermal softening group than in the control group (35.1% vs 52.7%, P = .02). Moreover, thermal softening decreased the mean NRS score for sore throat in the thermal softening group by 10% an hour after extubation (thermal softening group, 1.29 [95% CI, 0.88-1.70] vs control group, 2.33 [95% CI, 1.77-2.89]; P < .01). At 24 hours after extubation, the incidence of sore throat (38.3% vs 40.7%, P = .77) and hoarseness (34.0% vs 35.2%, 0.95 [0.52-1.74], P = .74) were comparable between the two groups.

CONCLUSIONS

Intubation using endotracheal tubes with thermal softening significantly decreased the incidence of sore throat 1 hour after extubation when compared with endotracheal tubes without thermal softening.

Emergency Tracheal Intubation in Patients with COVID-19: Experience from a UK Centre

This retrospective observational case series describes a single centre's preparations and experience of 53 emergency tracheal intubations in patients with COVID-19 respiratory failure. The findings of a contemporaneous online survey exploring technical and nontechnical aspects of airway management, completed by intubation team members, are also presented. Preparations included developing a COVID-19 intubation standard operating procedure and checklist, dedicated airway trolleys, a consultant-led mobile intubation team, and an airway education programme. Tracheal intubation was successful in all patients. Intubation first-pass success rate was 85%, first-line videolaryngoscopy use 79%, oxygen desaturation 49%, and hypotension 21%. Performance was consistent across all clinical areas. The main factor impeding first-pass success was larger diameter tracheal tubes. The majority of intubations was performed by consultant anaesthetists. Nonconsultant intubations demonstrated higher oxygen desaturation rates (75% vs. 45%, p=0.610) and lower first-pass success (0% vs. 92%, p < 0.001). Survey respondents (n = 29) reported increased anxiety at the start of the pandemic, with statistically significant reduction as the pandemic progressed (median: 4/5 very high vs. 2/5 low anxiety, p < 0.001). Reported procedural/environmental challenges included performing tasks in personal protective equipment (62%), remote-site working (48%), and modification of normal practices (41%)-specifically, the use of larger diameter tracheal tubes (21%). Hypoxaemia was identified by 90% of respondents as the most challenging patient-related factor during intubations. Our findings demonstrate that a consultant-led mobile intubation team can safely perform tracheal intubation in critically ill COVID-19 patients across all clinical areas, aided by thorough preparation and training, despite heightened anxiety levels.

Laryngotracheal injuries after intubation in pediatric seizure patients: A case series and a review of the literature

Acute management of seizures may require intubation with an endotracheal tube (ETT) in addition to benzodiazepine administration. Although necessary for management at times, intubation can lead to laryngotracheal injury as has been reported at length in both the adult and pediatric populations. A review of the literature shows no prior reports of laryngotracheal injuries following intubation in actively seizing pediatric patients. We share our experience with two pediatric patients who had laryngotracheal injuries after being emergently intubated with large ETT's during management of their seizures. We describe two unique cases in the pediatric seizure population associated with laryngotracheal injuries with the goal of emphasizing appropriate ETT sizing for intubation.

Current Practices in Endotracheal Tube Size Selection for Adults

OBJECTIVES/HYPOTHESIS

Intubation with inappropriately sized endotracheal tubes (ETT) can cause long-term tracheal and laryngeal injuries often requiring surgical intervention. Although tracheal size has been demonstrated to vary based on height and sex, it is unclear whether these guidelines are regularly implemented in patients undergoing endotracheal intubation. The objective of this study is to determine the rate of appropriate ETT size selection in patients undergoing intubation and assess provider decision making in ETT size selection.

STUDY DESIGN

Retrospective cohort study.

METHODS

The study population was all patients who underwent endotracheal intubation over a two-week period at a tertiary academic medical center. Data were collected on patient age, gender, height, BMI, comorbidities, ETT size, duration of intubation, bronchoscopies, and type of practitioner who performed the intubation. A height-based nomogram for ETT size selection was used to determine the recommended ETT size for each patient.

RESULTS

One hundred five patients met the inclusion criteria. 22% of patients were intubated with an inappropriately large tube, defined as 1.0 mm larger than the recommended size. Women were more likely to be intubated with an inappropriately large ETT (OR = 13.58, P = .001), as were patients with height less than 160 cm (OR = 141, P = .001). Other factors related to disease severity, anticipation for bronchoscopy, and BMI were not risk factors for the use of inappropriately large ETT.

CONCLUSIONS

Although there is compelling evidence that height is a strong predictor of tracheal morphology and appropriate ETT size, height-based guidelines have yet to be universally adopted for ETT size selection. Laryngoscope, 131:1967-1971, 2021.

Tracheal tube size in adults undergoing elective surgery - a narrative review

Tracheal tubes are routinely used in adults undergoing elective surgery. The size of the tracheal tube, defined by its internal diameter, is often generically selected according to sex, with 7-7.5 mm and 8-8.5 mm tubes recommended in women and men, respectively. Tracheal diameter in adults is highly variable, being narrowest at the subglottis, and is affected by height and sex. The outer diameter of routinely used tracheal tubes may exceed these dimensions, traumatise the airway and increase the risk of postoperative sore throat and hoarseness. These complications disproportionately affect women and may be mitigated by using smaller tracheal tubes (6-6.5 mm). Patient safety concerns about using small tracheal tubes are based on critical care populations undergoing prolonged periods of tracheal intubation and not patients undergoing elective surgery. The internal diameter of the tube corresponds to its clinical utility. Tracheal tubes as small as 6.0 mm will accommodate routinely used intubation aids, suction devices and slim-line fibreoptic bronchoscopes. Positive pressure ventilation may be performed without increasing the risk of ventilator-induced lung injury or air trapping, even when high minute volumes are required. There is also no demonstrable increased risk of aspiration or cuff pressure damage when using smaller tracheal tubes. Small tracheal tubes may not be safe in all patients, such as those with high secretion loads and airflow limitation. A balanced view of risks and benefits should be taken appropriate to the clinical context, to select the smallest tracheal tube that permits safe peri-operative management.

Intensive Care Unit Management of a Patient with Tracheal Rent Repair Following Laryngopharyngoesophagectomy

Tracheal injuries are one of the potentially fatal complications following laryngopharyngeal and esophageal surgeries. The patient developed tracheal rent during laryngopharyngoesophagectomy. The injury was diagnosed intraoperative and repaired. However, it did not heal, and the patient developed tracheopleural fistula. Right thoracotomy and latissimus dorsi flap was done under general anesthesia. Postsurgery, the patient was shifted to intensive care unit (ICU), where he developed respiratory distress not improving, with increasing oxygen flows. To avoid damage to the repair, under bronchoscopic guidance bilateral selective mainstem bronchial intubations were done using cuffed 5.0 mm regular endotracheal tubes (ETTs), and ventilation was supported on pressure control ventilation mode. The ventilator support was weaned off to pressure support ventilation mode on postoperative day (POD) 1. On POD2, ETTs were removed under bronchoscopic guidance and were replaced by 7 mm ID long and adjustable flange tracheostomy tube with the tip just above the carina. The cuff was kept deflated, and oxygen with the high flow was provided through a tracheostomy. The high flow was weaned off after 5 days. Later, the patient was managed conservatively by regular chest physiotherapy, antibiotics, bronchoscopic pulmonary toileting, nebulizations, and appropriate antimicrobial therapy. Patient was discharged in stable condition from ICU and hospital.

Upper airway tract complications of endotracheal intubation

The gold standard in airway maintenance is translaryngeal endotracheal intubation, but this is not without its complications. Trauma to the upper airway as a result of the act of endotracheal intubation is a common event in adults undergoing procedures under general anaesthesia. Sites requiring attention during intubation include the laryngeal apparatus, the pharynx and oral cavity as well as the nasal cavity when nasopharyngeal intubation is performed. Patients can present with a range of symptoms which can make assessment and management challenging. Dysphonia, throat pain and dysphagia are the commonest presenting complaints. Patient-related factors, intubation technique and other anaesthetic-related conditions can be a cause of trauma, if not adequately considered before intubation. All patients should be carefully examined preoperatively and their past medical history obtained. Patient demographics, comorbidities, existing airway pathology and presence of reflux should be noted. Trauma prevention strategies should be in place to eliminate avoidable complications. Potential difficult airway cases should be flagged up and adequately prepared for, in anticipation of intubation difficulties that can lead to trauma. The majority of injuries will resolve spontaneously with conservative management. Persistent symptomatology, usually secondary to laryngeal injuries, requires prompt referral to an ear nose and throat specialist with an interest in laryngology for further assessment and treatment.

Proposing an Endotracheal Tube Selection Tool Based on Multivariate Analysis of Airway Imaging

OBJECTIVES

We aimed to comprehensively investigate different upper airway segments in adults, determine the predictors of the size of each segment, and identify an appropriate endotracheal tube (ETT) size chart.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care center.

MATERIALS AND METHODS

The data for patients aged >18 years who underwent neck computed tomography were screened. Patients with existing tumors, trauma, or any pathology that can alter the normal airway anatomy and those with intubation, tracheostomy, or nasogastric tubes were excluded. Computed tomography software was used to measure the anteroposterior diameter (APD), transverse diameter (TD), and cross-sectional area (CSA) at the glottic, proximal subglottic, distal subglottic, and tracheal levels. Multiple regression analysis was used to identify the predictors of the airway size.

RESULTS

One hundred patients were reviewed. The TD was consistently smaller than or equal to the APD at each level in all but 3 patients. The mean CSA and TD (170 mm² and 11.3 mm, respectively) of the glottis indicated that the glottis was most often the narrowest level, followed by the proximal subglottis where the mean CSA and TD were 192.1 mm² and 12.7 mm, respectively. Moreover, the mean APD was the smallest at the level of the trachea (20.1 mm). Multiple regression analysis confirmed that height and sex were the predominant predictors of measurements for the 4 airway segments. In addition, age was associated with the TD and CSA of the distal subglottic and tracheal segments, respectively.

CONCLUSION

One-third of our participants exhibited a proximal subglottic diameter that was equal to or smaller than the glottic diameter. Our findings also suggested that the height and sex of the patients are important variables for the selection of an appropriate ETT size.

Targeted Drug Delivery to Upper Airways Using a Pulsed Aerosol Bolus and Inhaled Volume Tracking Method

The pulmonary route presents an attractive delivery pathway for topical treatment of lung diseases. While significant progress has been achieved in understanding the physical underpinnings of aerosol deposition in the lungs, our ability to target or confine the deposition of inhalation aerosols to specific lung regions remains meagre. Here, we present a novel inhalation proof-of-concept in silico for regional targeting in the upper airways, quantitatively supported by computational fluid dynamics (CFD) simulations of inhaled micron-sized particles (i.e. 1-10 μm) using an intubated, anatomically-realistic, multi-generation airway tree model. Our targeting strategy relies on selecting the particle release time, whereby a short-pulsed bolus of aerosols is injected into the airways and the inhaled volume of clean air behind the bolus is tracked to reach a desired inhalation depth (i.e. airway generations). A breath hold maneuver then follows to facilitate deposition, via sedimentation, before exhalation resumes and remaining airborne particles are expelled. Our numerical findings showcase how particles in the range 5-10 μm combined with such inhalation methodology are best suited to deposit in the upper airways, with deposition fractions between 0.68 and unity. In contrast, smaller (< 2 μm) particles are less than optimal due to their slow sedimentation rates. We illustrate further how modulating the volume inhaled behind the pulsed bolus, prior to breath hold, may be leveraged to vary the targeted airway sites. We discuss the feasibility of the proposed inhalation framework and how it may help pave the way for specialized topical lung treatments.

Incidence and risk factors for postoperative lingual neuropraxia following airway instrumentation: A retrospective matched case-control study

Background

Lingual nerve injury or neuropraxia is a rare but potentially serious perioperative complication following airway instrumentation during general anesthesia. This study explored the the incidence and perioperative risk factors for lingual nerve injury in patients receiving laryngeal mask (LMA) or endotracheal (ETGA) general anesthesia in a single center experience.

Methods and results

All surgical patients in our hospital who received LMA or ETGA from 2009 to 2013 were included, and potential perioperative risk factors were compared. Matched controls were randomly selected (in 1:5 ratio) from the same database in non-case patients. A total of 36 patients in the records had reported experiencing tongue numbness after anesthesia in this study. Compared with the non-case surgical population (n = 54314), patients with tongue numbness were significantly younger (52.2±19.5 vs 42.0±14.5; P = 0.002) and reported lower ASA physical statuses (2.3±0.7 vs 1.6±0.6; P<0.001). Patient gender, anesthesia technique used, and airway device type (LMA or ETGA) did not differ significantly across the two groups. A significantly higher proportion of patients underwent operations of the head-and-neck region (38.9 vs 15.6%; P = 0.002) developed tongue numbness after anesthesia. Multivariate logistic regression analysis indicated that head-and-neck operations remained the most significant independent risk factor for postoperative lingual nerve injury (AOR 7.63; 95% CI 2.03–28.70).

Conclusion

The overall incidence rate of postoperative lingual neuropraxy was 0.066% in patients receiving general anesthesia with airway device in place. Young and generally healthy patients receiving head-and-neck operation are at higher risk in developing postoperative lingual neuropraxy. Attention should be particularly exercised to reduce the pressure of endotracheal tube or laryngeal mask on the tongue during head-and-neck operation to avert the occurrence of postoperative lingual neuropraxy.

Guidelines for the management of tracheal intubation in critically ill adults

These guidelines describe a comprehensive strategy to optimize oxygenation, airway management, and tracheal intubation in critically ill patients, in all hospital locations. They are a direct response to the 4^th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society, which highlighted deficient management of these extremely vulnerable patients leading to major complications and avoidable deaths. They are founded on robust evidence where available, supplemented by expert consensus opinion where it is not. These guidelines recognize that improved outcomes of emergency airway management require closer attention to human factors, rather than simply introduction of new devices or improved technical proficiency. They stress the role of the airway team, a shared mental model, planning, and communication throughout airway management. The primacy of oxygenation including pre- and peroxygenation is emphasized. A modified rapid sequence approach is recommended. Optimal management is presented in an algorithm that combines Plans B and C, incorporating elements of the Vortex approach. To avoid delays and task fixation, the importance of limiting procedural attempts, promptly recognizing failure, and transitioning to the next algorithm step are emphasized. The guidelines recommend early use of a videolaryngoscope, with a screen visible to all, and second generation supraglottic airways for airway rescue. Recommendations for emergency front of neck airway are for a scalpel-bougie-tube technique while acknowledging the value of other techniques performed by trained experts. As most critical care airway catastrophes occur after intubation, from dislodged or blocked tubes, essential methods to avoid these complications are also emphasized.

A Comparative Study of Tracheal Diameter in Caucasian and Chinese Patients

Ethnicity may be considered a factor when considering what size endotracheal tube to insert. In particular it has been suggested that Chinese patients have a smaller tracheal diameter, justifying the selection of smaller endotracheal tubes. We systematically evaluated transverse tracheal diameters in Chinese and Caucasian patients, utilising archived computer tomography images. A convenience sample of 100 Caucasian patients from Australia was compared with 100 Chinese patients from Hong Kong. Patients over 18 years of age who had undergone a computerised tomography scan of the neck and thorax, and also had accurate body height and weight recorded, were studied. The mean transverse diameter of the trachea measured at three levels was similar between the Chinese and Caucasian patients. At the narrowest measurement point, the immediate subcricoid transverse diameter, the unadjusted mean difference between male Chinese and Caucasian patients was small (1 mm, standard deviation 0.83 mm, P=0.01), and similarly small between female Chinese and Caucasian patients (1.5 mm, standard deviation 0.8 mm, P <0.01). Multivariate analysis demonstrated only a small influence related to ethnicity (12% relative contribution to the overall variance [R2] of the model), but substantial influence of height (40%) and sex (41%). Our findings do not support the practice of routinely selecting a smaller endotracheal tube size for Chinese patients on the basis that there is a difference related to the Chinese ethnic phenotype. Considerations regarding choice of endotracheal tube size should rather focus on patient sex and height.

Tracheal Size Variability Is Associated With Sex

Purpose:

Whereas selection of endotracheal tube (ETT) size in pediatric patients benefits from predictive nomograms, adult ETT sizing is relatively arbitrary. We sought to determine associations between cervical tracheal cross-sectional area (CTCSA) and clinical variables.

Methods:

One hundred thirty-two consecutive patients undergoing noncontrasted chest computed tomography (CT) at a single tertiary care institution from January 2010 to June 2011 were reviewed. Patients with improper CT technique, endotracheal intubation, and pulmonary/tracheal pathology were excluded. Tracheal luminal diameters in anteroposterior (D1) and transverse (D2) were measured 2 cm inferior to the cricoid and used to determine CTCSA = π*D1*D2*¼. The demographic variables of age, height, weight, and body mass index (BMI) were tested for association with CTCSA by Spearman correlation. Wilcoxon rank-sum test was used to compare CTCSA by race and sex. Multivariate linear regression was performed including all clinical variables.

Results:

There were 91 patients who met inclusion criteria. There was no correlation between age, weight, or BMI and CTCSA. There was a significant positive correlation between patient height and CTCSA ( P = .001, R = 0.35); however, this was confounded by sex. Female patients had significantly smaller CTCSA (mean = 241 mm2) compared to male patients (mean = 349 mm2, P < .001). Multivariate linear regression stratified by sex revealed that height is correlated with CTCSA only in males ( P = .028). Males also had more variability in CTCSA (SD 118.6) compared to females (SD 65.5).

Conclusion:

Our data suggest that selection of ETT size in male patients should include height as a predictive factor. For female patients, it may be appropriate to select a uniformly smaller diameter ETT size.

Gender differences in sore throat and hoarseness following endotracheal tube or laryngeal mask airway: a prospective study

Background

Postoperative sore throat and hoarseness are common minor complications following airway manipulation. This study was primarily done to determine gender differences in the incidence of these symptoms and the location of POST after laryngeal mask airway (LMA) and endotracheal tube (ETT).

Methods

A total of 112 men and 185 women were included during a four month period. All patients were evaluated postoperatively and after 24 hours about the occurrence of sore throat, its location and hoarseness. If the patients had any symptom, they were followed-up at 48, 72 and 96 hours until the symptoms resolved.

Results

There was no significant gender difference in postoperative sore throat (POST) and postoperative hoarseness (PH) when analyzing both airway devices together. The incidence of sore throat and hoarseness were higher postoperatively after an ETT than an LMA (32% vs. 19%, p = 0.012) and 57% vs. 33% (p < 0.001) respectively. Significantly more women than men had POST after an LMA (26% vs. 6%, p = 0.004). No significant gender difference was found in either POST or PH after an ETT or in the incidence of PH after an LMA. More patients located their pain below the larynx after an ETT vs. an LMA (24% vs. 4%). Pain above the larynx was more common after an LMA than an ETT (52% vs. 37%).

Conclusions

In a clinical setting where women are intubated with a smaller size ETT than men, there were no significant differences in POST or PH between genders. Additionally, more women than men have POST when an LMA is used. Awareness of POST and PH may help streamline patients in whom the best airway device could be used during anesthesia and surgery.