Dimensions of the neonatal cricothyroid membrane - how feasible is a surgical cricothyroidotomy?

Video Versus Nonvideo in a Rabbit Training Model for Establishing an Emergency Front of Neck Airway in Children: A Prospective Trial

OBJECTIVES

Simulating a realistic "cannot intubate, cannot oxygenate" (CICO) situation to train an "emergency front of neck airway" is difficult. It further remains unclear if provision of regular technical refreshers improves performance in the setting of a real CICO situation. The purpose of this prospective study on an established surgical rabbit cadaver tracheostomy model was to evaluate the benefit of viewing training material shortly before performing "emergency front of neck airway."

METHODS

Previously trained participants were randomized into 2 groups. The control group (video) was allowed to watch an instructional video before performing a tracheotomy on the training model, while the study group (nonvideo) was not. Queried outcomes included success rate, performance time, and severe secondary airway injuries between the 2 groups.

RESULTS

In 29 tracheotomies performed by 29 participants, the overall success rate was 86% (92% video; 81% nonvideo, P = 0.4). Performance time was not different between the 2 groups (video: 80 s [IQR25-75: 53-86], nonvideo 64 s [IQR25-75: 47-102]; P = 0.93). Only in the nonvideo group, the performance time and the time between the workshops correlated positively (P = 0.048). Severe secondary injuries were noted in 4 of 29 rabbit cadavers, 2 in each group. Watching a refresher video before performing an emergency surgical tracheostomy in an infant training model did not influence the success rate and the performance time in previously trained anesthetists.

CONCLUSIONS

These results highlight the ease of learning, memorization, and recall of this emergency surgical tracheostomy technique and may demonstrate its applicability in a real infant CICO situation.

Emergency front-of-neck access in pediatric anesthesia: A narrative review

BACKGROUND AND OBJECTIVES

Children undergoing airway management during general anesthesia may experience airway complications resulting in a rare but life-threatening situation known as "Can't Intubate, Can't Oxygenate". This situation requires immediate recognition, advanced airway management, and ultimately emergency front-of-neck access. The absence of standardized procedures, lack of readily available equipment, inadequate knowledge, and training often lead to failed emergency front-of-neck access, resulting in catastrophic outcomes. In this narrative review, we examined the latest evidence on emergency front-of-neck access in children.

METHODS

A comprehensive literature was performed the use of emergency front-of-neck access (eFONA) in infants and children.

RESULTS

Eighty-six papers were deemed relevant by abstract. Finally, eight studies regarding the eFONA technique and simulations in animal models were included. For all articles, their primary and secondary outcomes, their specific animal model, the experimental design, the target participants, and the equipment were reported.

CONCLUSION

Based on the available evidence, we propose a general approach to the eFONA technique and a guide for implementing local protocols and training. Additionally, we introduce the application of innovative tools such as 3D models, ultrasound, and artificial intelligence, which can improve the precision, safety, and training of this rare but critical procedure.

Pilot cadaveric study on the feasibility of cricothyroidotomy and the associated complications in 30 cats

Objectives

The study's primary goal was to assess the feasibility of the cricothyroidotomy technique (CTT) in cats and evaluate its success rate (i.e., secure airway access). Secondary outcomes were the assessment of the subjective difficulty of airway access based on body score condition and weight. Further secondary outcomes consisted of procedural time and scoring of associated complications. The current study hypothesized that the CTT procedure would provide secure airway access with a reasonable success rate.

Materials and methods

A prospective experimental study assessing the performance of CTT and associated complications was conducted on 30 feline cadavers. A procedural datasheet was completed to subjectively grade difficulty of landmark palpation, guide placement and tube placement and expected success of the procedure. A dissection was then performed post-procedure by a blinded observer to evaluate for any associated damages.

Results

CTT was successful in securing an airway in 100% of the cats. The time to completion of the CTT was rapid, with a median time of 49 s (ranging from 31 to 90 s) for securing an airway. Of importance, this procedure was judged to be overall easy (median "ease of procedure score" of 7/10; ranging from 3 to 10) by the experimenters. The post-procedural lesion rate was elevated (76.7%) in this population of cats, though based on the lesion scores, was deemed mild in 73.9% of the cases.

Clinical significance

CTT warrants consideration as the primary option for emergency front-of-neck airway access for cats although further studies are necessary.

Emergency front-of-neck access in infants: A pragmatic crossover randomized control trial comparing two approaches on a simulated rabbit model

BACKGROUND

Rapid-sequence tracheotomy and scalpel-bougie tracheotomy are two published approaches for establishing emergency front-of-neck access in infants. It is unknown whether there is a difference in performance times and success rates between the two approaches.

AIMS

The aim of this cross-over randomized control trial study was to investigate whether the two approaches were equivalent for establishing tracheal access in rabbit cadavers. The underlying hypothesis was that the time to achieve the tracheal access is the same with both techniques.

METHODS

Between May and September 2022, thirty physicians (pediatric anesthesiologists and intensivists) were randomized to perform front-of-neck access using one and then the other technique: rapid-sequence tracheotomy and scalpel-bougie tracheotomy. After watching training videos, each technique was practiced four times followed by a final tracheotomy during which study measurements were obtained. Based on existing data, an equivalence margin was set at ∆ = ±10 s for the duration of the procedure. The primary outcome was defined as the duration until tracheal tube placement was achieved successfully. Secondary outcomes included success rate, structural injuries, and subjective participant self-evaluation.

RESULTS

The median duration of the scalpel-bougie tracheotomy was 48 s (95% CI: 37-57), while the duration of the rapid-sequence tracheotomy was 59 s (95% CI: 49-66, p = .07). The difference in the median duration between the two approaches was 11 s (95% CI: -4.9 to 29). The overall success rate was 93.3% (95% CI: 83.8%-98.2%). The scalpel-bougie tracheotomy resulted in significantly fewer damaged tracheal rings and was preferred among participants.

CONCLUSIONS

The scalpel-bougie tracheotomy was slightly faster than the rapid-sequence tracheotomy and favored by participants, with fewer tracheal injuries. Therefore, we propose the scalpel-bougie tracheostomy as a rescue approach favoring the similarity to the adult approach for small children. The use of a comparable equipment kit for both children and adults facilitates standardization, performance, and logistics.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05499273.

Anatomic Characteristics of the Adolescent Cricothyroid Membrane on Computed Tomography Scans

BACKGROUND

The cricothyroid membrane (CTM) is the most important anatomic structure when performing emergency front-of-neck access (FONA) procedures. Adolescence is a period of rapid morphologic change in laryngeal structures, including the CTM. We hypothesized that the adolescent CTM would be sufficiently different from pediatric or adult anatomy to merit special consideration in FONA.

OBJECTIVE

The aim of the study was to define the procedurally relevant CTM anatomy in an adolescent population.

METHODS

This was a retrospective, multicenter cohort study composed of patients who underwent a diagnostic computed tomography scan during routine clinical care. Inclusion criteria were ages 16 to 19 years and a computed tomography of the neck with or without contrast. The primary outcome was CTM height measured in the midsagittal plane using electronic calipers.

RESULTS

One hundred thirty-four imaging studies met inclusion criteria. The average CTM height was strongly associated with age and ranged between 5.4 and 6.2 mm in male adolescents and 4.6 and 5.8 mm in female adolescents. We predicted that standard cuffed endotracheal and tracheostomy tubes recommended for FONA procedures (5.0- and 6.0-mm devices) could potentially fail for most patients in our cohort.

CONCLUSIONS

The adolescent CTM is smaller than previously recognized. We recommend having a variety of equipment sizes readily available at any site where airway management in adolescents may occur.

Updated guideline on equipment to manage difficult airways: Australian and New Zealand College of Anaesthetists

The Australian and New Zealand College of Anaesthetists (ANZCA) recently reviewed and updated the guideline on equipment to manage a difficult airway. An ANZCA-established document development group, which included representatives from the Australasian College for Emergency Medicine and the College of Intensive Care Medicine of Australia and New Zealand, performed the review, which is based on expert consensus, an extensive literature review, and bi-nationwide consultation. The guideline (PG56(A) 2021, https://www.anzca.edu.au/getattachment/02fe1a4c-14f0-4ad1-8337-c281d26bfa17/PS56-Guideline-on-equipment-to-manage-difficult-airways) is accompanied by a detailed background paper (PG56(A)BP 2021, https://www.anzca.edu.au/getattachment/9ef4cd97-2f02-47fe-a63a-9f74fa7c68ac/PG56(A)BP-Guideline-on-equipment-to-manage-difficult-airways-Background-Paper), from which the current recommendations are reproduced on behalf of, and with the permission of, ANZCA. The updated 2021 guideline replaces the 2012 version and aims to provide an updated, objective, informed, transparent, and evidence-based review of equipment to manage difficult airways.

Cuffed versus uncuffed tracheal tubes in a rabbit training model for establishing an emergency front-of-neck airway in infants: a prospective trial

BACKGROUND

There is a paucity of evidence regarding the optimal type of tracheal tube to be advanced over a Frova catheter when performing a 'bougie' emergency front-of-neck airway (eFONA) technique in infants during a 'cannot intubate, cannot oxygenate' situation.

METHODS

A prospective non-inferiority trial in a rabbit cadaver surgical tracheotomy model to assess the performance of the eFONA technique with an uncuffed 3.5 mm ID tracheal tube vs a cuffed 3.0 mm ID tracheal tube. Queried outcomes include success rate, performance time, and severe secondary airway injuries among tracheal tube types.

RESULTS

In 60 tracheostomies performed by 30 participants, the overall success rate was 98%. Performance time was independent from tracheal tube choice (uncuffed: 61 s [95% confidence interval (CI), 52-76], cuffed: 64 s [95% CI, 55-79]; P = 0.82). No tracheal tube type was preferred in terms of usability by participants. The cuffed tracheal tube required increased force to be advanced over the Frova catheter and was associated with a risk ratio of 2.5 (95% CI, 0.53-11.9; number needed to harm, 10) for severe secondary airway injuries when compared with the uncuffed tracheal tube.

CONCLUSION

In performing eFONA in the rabbit cadaver model, an ID 3.5 uncuffed is non-inferior to an ID 3.0 cuffed tracheal tube regarding performance time and preference by the operator. Greater force application to advance the cuffed tube over the Frova catheter and more severe airway injuries may argue for the standardised performance of the eFONA technique with a uncuffed tracheal tube in infants.

"Cannot intubate, cannot oxygenate": A novel 2-operator technique for cannula tracheotomy in an infant animal model-a feasibility study

BACKGROUND

Evidence regarding optimal management of the "Cannot Intubate, Cannot Oxygenate" (CICO) scenario in infants is scarce. When inserting a transtracheal cannula for front of neck access direct aspiration to confirm intratracheal location is standard practice. This postmortem "infant airway" animal model study describes a novel technique for cannula tracheotomy.

AIMS

To compare a novel technique of cannula tracheotomy to an accepted technique to assess success and complication rates.

METHODS

Two experienced proceduralists repeatedly performed tracheotomy using an 18-gauge BD InsyteTM cannula (BD, Franklin Lakes, NJ, USA) in 6 postmortem White New Zealand rabbits. Cannulas were attached either directly to a 5ml syringe (Direct Aspiration) or via a 25 cm length minimum volume extension tubing set (TUTA Healthcare Lidcombe, NSW, Australia) (Indirect Aspiration, 2 operator technique). Each technique was attempted a maximum of 12 times per rabbit with an ENT surgeon assessing success and complication rates endoscopically for each attempt.

RESULTS

72 tracheotomy attempts were made in total, 36 for each technique. Initial aspiration through the needle was achieved in 93% (97.2% direct versus 89% indirect). Advancement of the cannula and continued aspiration (success) into the trachea occurred in 67% for direct compared with 64% for indirect aspiration. Direct aspiration was associated with higher rates of lateral (10.3% versus 5.6%) and posterior (19.4% versus 13.9%) wall injury compared with the indirect 2-operator technique.

CONCLUSION

Cannula tracheotomy in infant-sized airways is technically difficult and seems frequently associated with tracheal wall injury. The reduced incidence of injury in the indirect group warrants further investigation in preclinical and clinical trials.

Age-Related Changes in Upper Airway Anatomy Via Ultrasonography in Pediatric Patients

PURPOSE

Ultrasonography is a portable, noninvasive tool that may be used to evaluate the upper airway. The purpose of our study was to present a systematic approach to identify salient features of the pediatric airway and determine whether ultrasonography can identify anatomical changes that occur with growth and development.

METHODS

We present a prospective, observational trial where patients included were between 1 day and 10 years of age presenting for elective surgery who had no known history of unfavorable airway pathology. We sequentially obtained 5 ultrasound views under anesthesia: (1) sagittal sternal notch view of the trachea, (2) sagittal longitudinal view of trachea (LT), (3) axial view at the level of the vocal cords (AVC), (4) axial view at the level of the cricoid membrane (AC), and (5) sagittal longitudinal submental space view (SM). A broadband linear array transducer was used to identify airway structures and perform measurements.

RESULTS

Eighty-four percent of enrolled patients underwent airway imaging and were analyzed using multiple regression and Spearman correlation (ρ). In view 1, tracheal diameter via sagittal sternal notch view was immeasurable because of air disturbance. In the LT view, the distance from the skin to the cricothyroid membrane (LT1) did not statistically increase with age in days (P = 0.06); however, the distance from the cricoid to thyroid cartilage (LT2) did correlate to age (P < 0.001; 99% confidence interval [CI], 1.8 × 10-5, 7.7 × 10-5; ρ = 0.77, P = 0.001). We found a statistically significant relationship between age and the distance between the anterior and posterior commissures (AVC2; P < 0.001; 99% CI, 1.0 × 10-4, 1.7 × 10-4; ρ = 0.80, P < 0.001), the distance from the skin to the posterior commissure (AVC3; P < 0.001; 99% CI, 9.6 × 10-5, 2.0 × 10-4; ρ = 0.73, P < 0.001), the distance to the cricoid cartilage (AC; P < 0.001; 99% CI, 2.0 × 10-5, 7.7 × 10-5; ρ = 0.66, P < 0.001), and the distance from the tongue base to the soft palate (SM2; P < 0.001; 9% CI, 1.8 × 10-4, 3.9 × 10-4; ρ = 0.85, P < 0.001). There were no significant relationships between age and AVC1 (P = 0.16) and SM1 (P = 0.44).

CONCLUSIONS

Airway ultrasound is a feasible tool to evaluate the pediatric airway in children younger than 10 years; however, the detection of age-related changes of certain structures is limited to select measurements.

A Primer for Pediatric Emergency Front-of-the-Neck Access

"Cannot intubate, cannot oxygenate" situations in healthy children are uncommon but are often associated with poor outcomes. Clinical assessment, anticipatory planning, and the use of algorithms can lessen the likelihood of untoward outcomes, but the common final pathway of many algorithms for a difficult pediatric airway involves obtaining emergency tracheal access. The airway practitioner must have the know-how and training needed to invasively secure the airway when confronted with this rare but potentially devastating emergency. We provide practitioners with an overview of pediatric emergency front-of-the-neck access strategies and a structure for their management.

Rabbit training model for establishing an emergency front of neck airway in children

BACKGROUND

A 'cannot intubate, cannot oxygenate' (CICO) situation is rare in paediatric anaesthesia, but can always occur in children under certain emergency situations. There is a paucity of literature on specific procedures for securing an emergency invasive airway in children younger than 6 yr. A modified emergency front of neck access (eFONA) technique using a rabbit cadaver model was developed to teach invasive airway protection in a CICO situation in children.

METHODS

After watching an instructional video of our eFONA technique (tracheotomy, intubation with Frova catheter over which a tracheal tube is inserted), 29 anaesthesiologists performed two separate attempts on rabbit cadavers. The primary outcome was the success rate and the performance time overall and in subgroups of trained and untrained participants.

RESULTS

The overall success rate across 58 tracheotomies was 95% and the median performance time was 67 s (95% confidence interval [CI], 56-76). Performance time decreased from the first to the second attempt from 72 s (95% CI, 57-81) to 61 s (95% CI, 50-81). Performance time was 59 s (95% CI, 49-79) for untrained participants and 72 s (95% CI, 62-81) for trained participants. Clinical experience and age of the participants was not correlated with performance time, whereas the length of the tracheotomy incision showed a significant correlation (P=0.006).

CONCLUSION

This eFONA training model for children facilitates rapid skill acquisition under realistic anatomical conditions to perform an emergency invasive airway in children younger than 2 yr.

The Knowledge of Health Professionals About the Application of Cricoid Pressure in a Low-Income Country: A Single-Center Survey Study

BACKGROUND

The application of cricoid pressure requires good knowledge and practice of health professionals who are working in operation theatres to prevent pulmonary aspiration. This study aims to assess the application of cricoid pressure knowledge and practice in health professionals who are working in the operation theatres.

METHODS

This survey-based study was conducted in health care professionals who are working in the operation theatre of Debre Tabor Comprehensive Specialized Hospital from November 1 to December 1, 2020. A structured checklist was used to collect data regarding the knowledge and practice of the application of cricoid pressure.

RESULTS

A total of 43 health professionals who are working in the operation theaters were involved in this study with a response rate of 81%. The correct anatomic position of cricoid cartilage was not identified in 67% of nurses. We found that 78% of anesthetists did not use the nasogastric tube for decompression, and 83% of them complain of difficult intubation during the application of cricoid pressure.

CONCLUSION

Health care professionals who are working in operation theatres had poor knowledge and practice in the application of cricoid pressure.

Management of the Unexpected Difficult Airway in Neonatal Resuscitation

A "difficult airway situation" arises whenever face mask ventilation, laryngoscopy, endotracheal intubation, or use of supraglottic device fail to secure ventilation. As bradycardia and cardiac arrest in the neonate are usually of respiratory origin, neonatal airway management remains a critical factor. Despite this, a well-defined in-house approach to the neonatal difficult airway is often lacking. While a recent guideline from the British Pediatric Society exists, and the Scottish NHS and Advanced Resuscitation of the Newborn Infant (ARNI) airway management algorithm was recently revised, there is no Norwegian national guideline for managing the unanticipated difficult airway in the delivery room (DR) and neonatal intensive care unit (NICU). Experience from anesthesiology is that a "difficult airway algorithm," advance planning and routine practicing, prepares the resuscitation team to respond adequately to the technical and non-technical stress of a difficult airway situation. We learned from observing current approaches to advanced airway management in DR resuscitations in a university hospital and make recommendations on how the neonatal difficult airway may be managed through technical and non-technical approaches. Our recommendations mainly pertain to DR resuscitations but may be transferred to the NICU environment.

Tracheostomy in Infants in the Neonatal Intensive Care Unit

Approximately half of all pediatric tracheostomies are performed in infants younger than 1 year. Most tracheostomies in patients in the NICU are performed in cases of chronic respiratory failure requiring prolonged mechanical ventilation or upper airway obstruction. With improvements in ventilation and management of long-term intubation, indications for tracheostomy and perioperative management in this population continue to evolve. Evidence-based protocols to guide routine postoperative care, prevent and manage tracheostomy emergencies including accidental decannulation and tube obstruction, and attempt elective decannulation are sparse. Clinician awareness of safe tracheostomy practices and larger, prospective studies in infants are needed to improve clinical care of this vulnerable population.

Emerging trends, techniques, and equipment for airway management in pediatric patients

Pediatric patients present unique anatomic and physiologic considerations in airway management, which impose significant physiologic limits on safe apnea time before the onset of hypoxemia and subsequent bradycardia. These issues are even more pronounced for the pediatric difficult airway. In the last decade, the development of pediatric sized supraglottic airways specifically designed for intubation, as well as advances in imaging technology such that current pediatric airway equipment now finally rival those for the adult population, has significantly expanded the pediatric anesthesiologist's tool kit for pediatric airway management. Equally important, techniques are increasingly implemented that maintain oxygen delivery to the lungs, safely extending the time available for pediatric airway management. This review will focus on emerging trends and techniques using existing tools to safely handle the pediatric airway including videolaryngoscopy, combination techniques for intubation, techniques for maintaining oxygenation during intubation, airway management in patients at risk for aspiration, and considerations in cannot intubate cannot oxygenate scenarios.

Accuracy of pediatric cricothyroid membrane identification by digital palpation and implications for emergency front of neck access

BACKGROUND

Emergency front of neck access in a "can't intubate can't oxygenate" scenario in pediatrics is rare. Ideally airway rescue would involve the presence of an ear, nose, and throat surgeon. If unavailable however, responsibility lies with the anesthesiologist and accurate identification of anterior neck structures is essential for success.

AIM

We assessed anesthesiologists' accuracy in identification of the pediatric cricothyroid membrane by digital palpation in three predefined age groups (37 weeks to <1 year old, 1-8 years old, and 9-16 years old) and whether accuracy improved with repetition. We also investigated a novel hypothetical vertical skin incision strategy to successfully expose the cricothyroid membrane.

METHODS

We asked anesthesiologists to identify the location of the cricothyroid membrane of anesthetized children in the extended neck position. Accuracy was defined as a mark made within the margins of the cricothyroid membrane using ultrasound as a reference standard. The position of the cricothyroid membrane relative to the neck midpoint, between the suprasternal notch and mentum, was defined for each child. Using this neck midpoint, we determined the hypothetical vertical skin incision lengths required to successfully expose the cricothyroid membrane ("midpoint incision").

RESULTS

Ninety-seven patients were included in this study. There were 14, 58, and 25 patients recruited across the three predefined groups. Accurate anesthesiologist identification of the location of the cricothyroid membrane occurred in 29.4%, 28.6%, and 38.2% of attempts, respectively. The majority of inaccurate assessments (64.1%) were below the cricothyroid membrane. There was no improvement in accuracy with repetition. Hypothetical "midpoint incision" lengths of 20, 30, and 35 mm were required.

CONCLUSION

Significant anesthesiologist inaccuracy exists in locating the cricothyroid membrane in children of all ages. This has implications for the technical approach to emergency front of neck access and how we teach the management of "can't intubate can't oxygenate" in pediatric practice.

The management of unanticipated difficult airways in children of all age groups in anaesthetic practice - the position paper of an expert panel

Children form a specific group of patients, as there are significant differences between children and adults in both anatomy and physiology. Difficult airway may be unanticipated or anticipated. Difficulties encountered during intubation may cause hypoxia, hypoxic brain injury and, in extreme situations, may result in the patient’s death. There are few paediatric difficult-airway guidelines available in the current literature, and some of these have significant limitations. This position paper, intended for unanticipated difficult airway, was elaborated by the panel of specialists representing the Polish Society of Anaesthesiology and Intensive Care as well as the Polish Neonatal Society. It covers both elective intubation and emergency situations in children in all age groups. An integral part of the paper is an algorithm. The paper describes in detail all stages of the algorithm considering some modification in specific age groups, i.e. neonates.

Transtracheal jet oxygenation: Comparing the efficacy and safety of two self-made Y-connector devices with the ENK oxygen flow modulator™ in an infant animal model

BACKGROUND

Self-made Y-connector jet-oxygenation devices with wide-bore expiratory port have been described but not evaluated in infant models. Little is known about the effect of oxygen flow rates on jet oxygenation via transtracheal cannula.

AIMS

The aim of this study was to compare two self-made Y-connector jet-oxygenation devices against the ENK oxygen flow modulator™, and the effects of three different oxygen flow rates based on body weight, in both unobstructed and obstructed airways, on the time to re-oxygenate in a rabbit infant model. The aim was also to assess the effectiveness of an oxygen flow rate of 1 L/min, for re-oxygenation using ENK oxygen flow modulator™.

METHODS

Nine rabbits were grouped in threes: Group 1 had a Y-connector attached to an intravenous infusion tubing, Group 2 the same Y-connector attached to a perfusion oxygenator tubing and Group 3, ENK oxygen flow modulator™. From oxygen saturations of 75%, the rabbits were jet oxygenated using their assigned device for 10 minutes at each flow rate of 1 L/kg/min, 1.5 L/kg/min and 2 L/kg/min with their airways unobstructed and later, obstructed. Group 3 had additional experiments involving an absolute oxygen flow rate of 1 L/min.

RESULTS

All devices resulted in rapid re-oxygenation within 40 seconds at flow rates of 1 L/kg/min. Oxygen flow rates beyond 1 L/kg/min in obstructed airways resulted in high airway pressures. All rabbits in Group 3 with obstructed airways died from barotrauma when jet oxygenated at a flow rate of 1.5 L/kg/min. When an oxygen flow rate of 1 L/min was used in Group 3, there was a failure to re-oxygenate to SpO₂ 90% within 120 seconds in some rabbits.

CONCLUSION

Our animal model results suggest that self-made Y-connector jet-oxygenation devices with wide-bore expiratory port are efficacious and perhaps safer than ENK oxygen flow modulator™ in obstructed airways, and jet oxygenation with minimal oxygen flow rates starting at 1 L/kg/min or (age [years] + 4) L/min, whichever lower, should be considered.

Accuracy of ultrasound in measurement of the pediatric cricothyroid membrane

BACKGROUND

Emergency front of neck airway is a recommended airway rescue strategy in children over 1 year old. Surgical tracheostomy is advocated as the first-line technique, but in the absence of an ear, nose and throat surgeon cricothyroidotomy or tracheostomy is proposed. Recent research shows that clinical identification of the cricothyroid membrane is frequently inaccurate in older children and adults and has prompted investigation of ultrasound as a potential clinical tool for emergency front of neck airway. Advance knowledge of the dimensions of the pediatric cricothyroid membrane may assist clinicians in determining the feasibility of emergency front of neck airway, optimum technique, and equipment.

AIMS

The aim of this study was to assess the accuracy of ultrasound-assisted pediatric cricothyroid membrane localization and dimension measurement using magnetic resonance imaging as the reference standard.

METHODS

After structured training, two pediatric anesthesiology trainees used ultrasound to identify and measure the dimensions of the cricothyroid membrane in pediatric patients undergoing elective magnetic resonance imaging of the head and neck under general anesthesia. A pediatric radiologist reviewed the corresponding magnetic resonance imaging scans and measured the height of the cricothyroid membrane. The accuracy of the cricothyroid membrane height as measured by ultrasound was compared to that measured by magnetic resonance imaging.

RESULTS

Twenty-two patients were included in the study. The cricothyroid membrane was accurately identified by ultrasound in all cases. The correlation coefficient for cricothyroid membrane height measured by ultrasound and that measured by magnetic resonance imaging was 0.98 (95% C.I 0.95-0.99, P < 0.0001). The bias was -0.16 mm and the precision was 0.19 mm. All differences were within the a priori limits of agreement. The 95% limits of agreement were -0.54 to 0.22 mm.

CONCLUSION

Ultrasound can be used to accurately identify and measure cricothyroid membrane height in pediatric patients. This approach could have clinical and research utility.

Airway dimensions from fetal life to adolescence-A literature overview

BACKGROUND

Data on airway dimensions in pediatric patients are important for proper selection of pediatric airway equipment such as endotracheal tubes, double-lumen tubes, bronchial blockers, or stents. The aim of the present work was to provide a synopsis of the available data on pediatric airway dimensions.

METHODS

A systematic literature search was carried out in the PubMed database, Scopus, Embase, Web of Science, Prisma, and Google Scholar and secondarily completed by a reference search. Based on inclusion and exclusion criteria, a final selection of 109 studies with data on pediatric airway dimensions published from 1923 to 2018 were further analyzed.

RESULTS

Six different airway measurement methods were identified. They included anatomical examinations, chest X-ray, computed tomography, magnetic resonance tomography, bronchoscopy, and ultrasound. Anatomical studies were more abundant compared to other methods. Data provided were very heterogeneously presented and powered. In addition, due to different study conditions, they are hardly comparable. Among all, anatomical and computer tomography studies are thought to provide the most reliable data. Ultrasound is an upcoming technique to estimate airway parameters of fetus and premature infants. There was, in general, a lack of comprehensive studies providing a complete range of airway dimensions in larger groups of patients from birth to adolescence.

CONCLUSIONS

This work revealed a large heterogeneity of studies providing data on pediatric airway dimensions, making it impossible to compare, or assemble them to normograms for clinical use. Comprehensive studies in large population of children are needed to provide full range nomograms on pediatric airway dimensions.

Unanticipated Difficult Airway in a Neonate: Are we Prepared for this CHAOS?

Unanticipated difficult airway in a neonate is a challenging situation with many difficulties because of inherent anatomical variations. To complicate the situation there is a lack of appropriate equipment, expertise and established guidelines on the management of difficult airway in neonates and infants. There are few published reports regarding the use of available devices for emergency front-of-neck access. We report the case of airway management of a neonate with an unanticipated finding of subglottic stenosis. Subglottic stenosis is one of the aetiologies of congenital high airway obstruction syndrome, which may be diagnosed antenatally based on ultrasonography findings.

Management of pediatric 'cannot intubate, cannot oxygenate'

Case

“Cannot intubate, cannot oxygenate” (CICO) is a rare, life‐threatening situation. We describe a pediatric case of CICO and highlight some educational points.A 3‐year‐old boy who collapsed in the bathtub came to our emergency department. On admission, he went into cardiac arrest probably because of an airway obstruction. We judged his condition as CICO and carried out an emergent tracheostomy after several attempts to perform a cricothyroidotomy failed. We continued resuscitation; however, circulation did not return spontaneously.

Outcome

The child died, and the autopsy showed an airway obstruction caused by idiopathic anaphylaxis or acquired angioedema.

Conclusion

This case highlights that it can be anatomically difficult to perform a percutaneous cannula cricothyroidotomy and scalpel cricothyroidotomy safely in pediatric CICO cases. An emergent tracheostomy using the scalpel–finger–bougie technique on the proximal trachea should be considered in such cases.

All India Difficult Airway Association 2016 guidelines for the management of unanticipated difficult tracheal intubation in Paediatrics

The All India Difficult Airway Association guidelines for the management of the unanticipated difficult tracheal intubation in paediatrics are developed to provide a structured, stepwise approach to manage unanticipated difficulty during tracheal intubation in children between 1 and 12 years of age. The incidence of unanticipated difficult airway in normal children is relatively rare. The recommendations for the management of difficult airway in children are mostly derived from extrapolation of adult data because of non-availability of proven evidence on the management of difficult airway in children. Children have a narrow margin of safety and mismanagement of the difficult airway can lead to disastrous consequences. In our country, a systematic approach to airway management in children is lacking, thus having a guideline would be beneficial. This is a sincere effort to protocolise airway management in children, using the best available evidence and consensus opinion put together to make airway management for children as safe as possible in our country.

An institutional approach to the management of the 'Can't Intubate, Can't Oxygenate' emergency in children

The 'Can't Intubate Can't Oxygenate' emergency is rare in children. Nevertheless, airway clinicians involved in pediatric airway management must be able to rescue the airway percutaneously through the front of the neck should this situation be encountered. Little evidence exists in children to guide rescue techniques, and extrapolation of adult evidence may be problematic due to anatomical differences. This document reviews the currently available evidence, and presents a practical approach to standardizing equipment, techniques, and training for managing the 'Can't Intubate Can't Oxygenate' emergency in children.

The role for surgery in pre-hospital care

Pre-hospital care requires a broad skillset. One of the most challenging aspects of pre-hospital care is performing surgical procedures. The indications and evidence for performing pre-hospital surgical airway, thoracostomy, thoracotomy, caesarean section and amputation are discussed. Where evidence for the procedure is lacking from pre-hospital care, evidence from in-hospital experience is sought.

Indications and results of emergency surgical airways performed by a physician-staffed helicopter emergency service

BACKGROUND

Airway management is essential in critically ill or injured patients. In a "can't intubate, can't oxygenate" scenario, an emergency surgical airway (ESA), similar to a cricothyroidotomy, is the final step in airway management. This procedure is infrequently performed in the prehospital or clinical setting. The incidence of ESA may differ between physician- and non-physician-staffed emergency medical services (EMS). We examined the indications and results of ESA procedures among our physician-staffed EMS compared with non-physician-staffed services.

METHODS

Data for all forms of airway management were obtained from our EMS providers and analyzed and compared with data from non-physician-staffed EMS found in the literature.

RESULTS

Among 1871 patients requiring a secured airway, the incidence of a surgical airway was 1.6% (n=30). Fourteen patients received a primary ESA. In 16 patients, a secondary ESA was required after failed endotracheal intubation. The total prehospital ESA tracheal access success rate was 96.7%.

CONCLUSION

The incidence of ESA in our patient population was low compared with those reported in the literature from non-physician-staffed EMS. Advanced intubation skills might be a contributing factor, thus reducing the number of ESAs required.

The 'Can't intubate can't oxygenate' scenario in pediatric anesthesia: a comparison of the Melker cricothyroidotomy kit with a scalpel bougie technique

BACKGROUND

While the majority of pediatric intubations are uncomplicated, the 'Can't intubate, Can't Oxygenate' scenario (CICO) does occur. With limited management guidelines available, CICO is still a challenge even to experienced pediatric anesthetists.

OBJECTIVES

To compare the COOK Melker cricothyroidotomy kit (CM) with a scalpel bougie (SB) technique for success rate and complication rate in a tracheotomy on a cadaveric 'infant airway' animal model.

METHODS

Two experienced proceduralists repeatedly attempted tracheotomy in eight rabbits, alternately using CM and SB (4 fr) technique. The first attempt was performed at the level of the first tracheal cartilage with subsequent experimental trials of insertion progressively more caudad. Success was defined as intratracheal placement of cannula as seen on bronchoscope. Complications were assessed both by bronchoscopic and macropathological appearance.

RESULTS

32 attempts were made at tracheotomy. CM had an overall success rate of 100% compared to a 75% success rate for SB. Success rate for the first attempt was dependent on the level of the tracheotomy (Level 1 100%, level 2 62.5% and level 3 & 4 25%). While CM was associated with lateral and/or posterior wall damage on bronchoscopy/macropathology in 6% of 19% and 25% of 50% respectively, the damage observed was greater and more frequent with SB (19%/44% and 31%/50%, respectively).

CONCLUSIONS

At level 1, the first attempt success rate was 100% for both devices. Overall CM showed a better success rate than SB; however, both techniques were associated with significant complication rates, which were more pronounced following the scalpel bougie technique.

Pediatric airway management

Securing an airway is a vital task for the anesthesiologist. The pediatric patients have significant anatomical and physiological differences compared with adults, which impact on the techniques and tools that the anesthesiologist might choose to provide safe and effective control of the airway. Furthermore, there are a number of pathological processes, typically seen in the pediatric population, which present unique anatomical or functional difficulties in airway management. The presence of one of these syndromes or conditions can predict a "difficult airway." Many instruments and devices are currently available which have been designed to aid in airway management. Some of these have been adapted from adult designs, but in many cases require alterations in technique to account for the anatomical and physiological differences of the pediatric patient. This review focuses on assessment and management of pediatric airway and highlights the unique challenges encountered in children.

Time to adequate oxygenation following ventilation using the Enk oxygen flow modulator versus a jet ventilator via needle cricothyrotomy in rabbits

INTRODUCTION

Limited information is available on the management of the 'cannot intubate, cannot ventilate' (CICV) situation in infants. We compared the time to achieve adequate oxygenation following rescue ventilation using the Enk oxygen flow modulator (OFM) with a jet ventilator in a simulated CICV situation using the rabbit as an infant respiratory model.

METHODS

Following institutional ethics committee approval, needle cricothyrotomy was performed under direct vision in nine anesthetized rabbits following surgical exposure of the larynx. After ensuring adequate level of anesthesia and analgesia, and confirming proper positioning of the 18G cannula, apnea was induced by the administration of myorelaxant and the SpO2 was allowed to drop to 75% before initiating rescue ventilation via either the OFM or jet ventilator.

RESULTS

Five rabbits were ventilated with the OFM and four with the jet ventilator. Ventilation was maintained with either device for 15 min. All rabbits were successfully rescued using either device. There was no statistical difference in the time required for SpO2 to return to 80%, 85%, 90%, and 95%.

CONCLUSIONS

Both devices facilitated successful rescue ventilation through a needle cricothyrotomy.

Parker Flex-Tip or standard tracheal tube for percutaneous emergency airway access?

BACKGROUND

Percutaneous emergency airway access (PEAA) can be established utilising a scalpel, bougie and cuffed tracheal tube. The study compared the Parker Flex-Tip tracheal tube with a standard tracheal tube for PEAA in cadavers. We hypothesised that a standard tracheal tube would be more likely to advance over a bougie into the trachea during a PEAA procedure than a Parker Flex-Tip tracheal tube.

METHODS

Three anaesthetists performed a PEAA with a scalpel, bougie and cuffed tracheal tube, 12 times each. Recorded times included: loading the tracheal tube onto the bougie and advancing the tube over the bougie to the skin, advancing the tube through the skin into the trachea and completion of the whole procedure. Subjective opinion regarding the ease of tube insertion was recorded by visual analogue scoring.

RESULTS

Subjective opinion, overall time and time to complete each component of the procedure were not significantly affected by the type of tube used. The mean time for three novice anaesthetists to complete PEAA on a cadaver was 37.5 (8.8) s, after 1 h of training. In two of the 12 cadavers, the cricothyroid membrane could not be palpated or located with the scalpel.

CONCLUSION

The Parker Flex-Tip tube and a standard tracheal tube perform equally well during PEAA procedures on adult cadavers.

Failed intubation and failed oxygenation in a child

A 'can't intubate, can't oxygenate' scenario in a child is fortunately extremely rare. We report a case of this life-threatening event in a four-year-old boy suffering from a rare genetic disorder, fibrodysplasia ossificans progressiva. He presented for manipulation of his dislocated jaw and was identified preoperatively as having a difficult airway. Despite extensive preparation, a catastrophic loss of airway control occurred minutes after induction of general anaesthesia, necessitating a life saving emergency tracheostomy. This report highlights the small evidence base and lack of definitive algorithms relating to how best to rescue a paediatric 'can't intubate, can't oxygenate' situation. Paediatric anatomical factors dictate that immediate procession to a tracheal surgical airway may be the optimal management.

The 'Can't Intubate Can't Oxygenate' scenario in Pediatric Anesthesia: a comparison of different devices for needle cricothyroidotomy

BACKGROUND

Little evidence exists to guide the management of the 'Can't Intubate, Can't Oxygenate' (CICO) scenario in pediatric anesthesia.

OBJECTIVES

To compare two intravenous cannulae for ease of use, success rate and complication rate in needle tracheotomy in a postmortem animal model of the infant airway, and trial a commercially available device using the same model.

METHODS

Two experienced proceduralists repeatedly attempted cannula tracheotomy in five postmortem rabbits, alternately using 18-gauge (18G) and 14-gauge (14G) BD Insyte(™) cannulae (BD, Franklin Lakes, NJ, USA). Attempts began at the first tracheal cartilage, with subsequent attempts progressively more caudad. Success was defined as intratracheal cannula placement. In each rabbit, an attempt was then made by each proceduralist to perform a cannula tracheotomy using the Quicktrach Child(™) device (VBM Medizintechnik GmbH, Sulz am Neckar, Germany).

RESULTS

The rabbit tracheas were of similar dimensions to a human infant. 60 attempts were made at cannula tracheotomy, yielding a 60% success rate. There was no significant difference in success rate, ease of use, or complication rate between cannulae of different gauge. Successful aspiration was highly predictive (positive predictive value 97%) and both sensitive (89%) and specific (96%) for tracheal cannulation. The posterior tracheal wall was perforated in 42% of tracheal punctures. None of 13 attempts using the Quicktrach Child(™) were successful.

CONCLUSION

Cannula tracheotomy in a model comparable to the infant airway is difficult and not without complication. Cannulae of 14- and 18-gauge appear to offer similar performance. Successful aspiration is the key predictor of appropriate cannula placement. The Quicktrach Child was not used successfully in this model. Further work is required to compare possible management strategies for the CICO scenario.

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.

Equipment to manage a difficult airway during anaesthesia

Airway complications are a leading cause of morbidity and mortality in anaesthesia. Effective management of a difficult airway requires the timely availability of suitable airway equipment. The Australian and New Zealand College of Anaesthetists has recently developed guidelines for the minimum set of equipment needed for the effective management of an unexpected difficult airway (TG4 [2010] www.anzca.edu.au/resources/professionaldocuments). TG4 [2010] is based on expert consensus, underpinned by wide consultation and an extensive review of the available evidence, which is summarised in a Background Paper (TG4 BP [2010] www.anzca.edu.au/ resources/professional-documents). TG4 [2010] will be reviewed at the end of one year and thereafter every five years or more frequently if necessary. The current paper is reproduced directly from the Background Paper (TG4 BP [2010]).

Cannot ventilate-cannot intubate an infant: surgical tracheotomy or transtracheal cannula?

BACKGROUND

An unanticipated difficult airway is very uncommon in infants. The recommendations for managing the cannot ventilate-cannot intubate (CVCI) situation in infants and small children are based on difficult airway algorithms for adults. These algorithms usually recommend placement of a transtracheal cannula or performing a surgical tracheotomy as a last resort. In this study, we compared the success rate and time used for inserting a transtracheal cannula vs performing a modified surgical tracheotomy in a piglet model.

METHODS

We used 10 three-week-old euthanized piglets, weighing eight kilograms each. Thirty physicians had a timed attempt of inserting a transtracheal cannula for jet ventilation. A maximum time of 120 s was allowed. Ten physicians had a timed attempt of performing a modified surgical tracheotomy after a short introduction by an ENT surgeon. The allowed time for this procedure was 240 s.

RESULTS

Placement of the transtracheal cannula was successful for eight of 30 physicians. Median time for successful insertion was 68 s. Surgical tracheotomy was successful for 8 of 10 physicians. Median time for successful tracheotomy was 89 s. There was a significantly higher success rate for surgical tracheotomy (P = 0.007).

CONCLUSIONS

We found placement of a transtracheal cannula to be significantly less successful than the modified surgical tracheotomy in a piglet model. We question whether placement of a transtracheal cannula should be recommended in infants in a cannot ventilate-cannot intubate situation.

Proposal for the management of the unexpected difficult pediatric airway

The incidence of unanticipated difficult or failed airway in otherwise healthy children is rare, and routine airway management in pediatric patients is easy in experienced hands. However, difficulties with airway management in healthy children are not infrequent in nonpediatric anesthetists and are a main reason for pediatric anesthesia-related morbidity and mortality. Clear concepts and strategies are, therefore, required to maintain oxygenation and ventilation in children. Several complicated algorithms for the management of the unanticipated difficult adult and pediatric airway have been proposed, but a simple structured algorithm for the pediatric patient with unanticipated difficult airway is missing. This paper proposes a simple step-wise algorithm for the unexpected difficult pediatric airway based on an adult Difficult Airway Society (DAS) protocol, discusses the role of recently introduced airway devices, and suggests a content of a pediatric airway trolley. It is intended as an easy to memorize and a practical guide for the anesthetist only occasionally involved in pediatric anesthesia care as well as a call to stimulate discussion about the management of the unanticipated difficult pediatric airway.