The role of ultrasound in appropriate endotracheal tube size selection in pediatric patients

The accuracy of the ultrasound measured transverse cricoid diameter and the epiphyseal transverse diameter of the distal radius in predicting the pediatric endotracheal tube size

BACKGROUND

In everyday pediatric anesthesia practice, clinicians frequently exchange an already inserted endotracheal tube because of a leak or resistance causing significant morbidity. We investigated the accuracy of two ultrasound measurements; the transverse cricoid diameter and epiphyseal diameter of the distal radius in the prediction of endotracheal tube size that best fits in children compared to age-based formulas.

PATIENTS

One hundred children (1-6 years) who underwent elective surgery with endotracheal tube whether cuffed (n = 50) or uncuffed (n = 50) were enrolled. The primary endpoint was the agreement between the reference tube size for which its outer diameter was selected based on transverse cricoid diameter and the final best-fit-ETT. The Correlation and Bland Altman agreement tests were conducted between best-fit-ETT outer diameter and ultrasound-measured outer diameter, and between best-fit-ETT inner diameter and inner diameter calculated by age-based formulas.

RESULTS

The agreement rate between transverse cricoid diameter-based endotracheal tube size and best-fit-ETT size was 88% in cuffed group compared to 90% in uncuffed group. A significant positive correlation was reported between the outer diameter of best-fit-ETT and the outer diameter measured by the two ultrasound methods. A lower degree of positive correlation was reported between the inner diameter of best-fit-ETT, and the inner diameter calculated by age-based formulas. Bland Altman's analysis showed agreement between best-fit-ETT outer diameter and epiphyseal diameter of the distal radius in both groups and with transverse cricoid diameter in the cuffed group, with no agreement with age-based formulas in either group.

CONCLUSIONS

Both transverse cricoid diameter and epiphyseal diameter of the distal radius are reliable predictors of the size of best-fit-ETT pediatric endotracheal tube compared to age-based formulas. To save time and effort, we recommend the US measurement of the epiphyseal diameter of distal radius in the preoperative visit and documenting the predicted tube size with the preoperative assessments.

A Scoping Review of Ultrasonographic Techniques in the Evaluation of the Pediatric Airway

Point-of-care ultrasound is making rapid advancements in pediatrics, and ultrasonographic assessment of the airway is being employed in many specialties such as the pediatric, cardiac, and neonatal intensive care units, emergency department, pulmonary clinic, and the perioperative setting. This scoping review provides a technical description of image acquisition and interpretation, accompanying ultrasound images of the hallmark airway applications in pediatrics, and supporting evidence when available. We describe and illustrate ultrasound-determined endotracheal tube (ETT) sizing, ETT placement and depth confirmation, vocal fold assessment, prediction of post-extubation stridor, difficult laryngoscopy prediction, and cricothyrotomy guidance. This review aims to provide the descriptions and images necessary to learn and apply these skills at the point of care in the pediatric patient.

Examining the pediatric subglottic airway by ultrasound: A systematic review

OBJECTIVE

The purpose of this review was to determine the ability of ultrasound (US) to assess the subglottic airway in pediatric patients to estimate the appropriate size of endotracheal tube (ETT).

DATA SOURCES

Pubmed, Scopus, and Embase databases.

METHODS

A search of the literature was performed for studies that utilized ultrasonography to examine the minimal transverse diameter of the subglottic airway (MTDSA) in the pediatric (age < 18) population to estimate endotracheal tube (ETT) size. Articles were excluded if they involved adults or non-humans, had no comparison method, or were case reports. The primary outcome was the successful use of ultrasound compared to the reference standard defined by the study.

RESULTS

Sixteen studies were included, for a total of 1,633 pediatric subjects in whom transcervical laryngeal ultrasound was used prospectively to examine the MTDSA to estimate ETT size prior to intubation. Ultrasound reliably predicted the clinically best fit endotracheal tube by air leak test in 48-100% of subjects, while age-based formulas were accurate 24-95% of the time. Ultrasound was highly predictive of proper size, with R2 ranging between 0.684 to 0.980. Of those reintubated (n = 104), 86 (83%) required larger-sized tubes, while 18 (17%) required smaller-sized tubes. Both methods tended to underestimate ETT size, but the age-based formulas accounted for most of these differences.

CONCLUSION

Transcervical laryngeal ultrasound appears to be a reliable predictor of endotracheal tube size in children undergoing elective surgery, which has implications for preventing intubation-related trauma and ensuring adequate ventilation for those who may require prolonged intubation.

Accuracy of Age-Based Formula to Predict the Size and Depth of Cuffed Oral Preformed Endotracheal Tubes in Children Undergoing Tonsillectomy

OBJECTIVES

To retrospectively investigate the reliability of the age-based formula, year/4 + 3.5 mm in predicting size and year/2 + 12 cm in predicting insertion depth of preformed endotracheal tubes in children and correlate these data with the body mass index.

PATIENTS AND METHODS

Patients were classified into 4 groups according to their nutritional status: thinness, normal weight, overweight, and obesity; we then retrospectively compared the actual size of endotracheal tube and insertion depth to the predicting age-based formula and to the respective bend-to-tip distance of the used preformed tubes.

RESULTS

Altogether, 300 patients were included. The actual endotracheal tube size corresponded with the Motoyama formula (64.7%, 90% CI: 60.0-69.1), except for thin patients, where the calculated size was too large (0.5 mm). The insertion depth could be predicted within the range of the bend-to-tip distance and age-based formula in 85.0% (90% CI: 81.3-88.0) of patients.

CONCLUSION

Prediction of the size of cuffed preformed endotracheal tubes using the formula of Motoyama was accurate in most patients, except in thin patients (body mass index < -2 SD). The insertion depth of the tubes was mostly in the range of the age-based-formula to the bend-to-tip distance.

Applications of Airway Ultrasound for Endotracheal Intubation in Pediatric Patients: A Systematic Review

Endotracheal intubation is a challenging procedure for pediatric patients. Airway ultrasound as a new technology is suitable for aiding this process, but its diagnostic value remains unclear. We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and the Chinese biomedical literature database to summarize specific applications of airway ultrasound in each step of endotracheal intubation in pediatric patients. Diagnostic accuracy and 95% confidence interval were used as outcomes. In total, 33 studies (6 randomized controlled trials and 27 diagnostic studies) with 1934 airway ultrasound examinations were included. Population included neonates, infants, and older children. Airway ultrasound could be used to determine the endotracheal tube size and confirm endotracheal intubation and intubation depth; the diagnostic accuracy for all these factors was 23.3-100%, 90.6-100%, and 66.7-100%, respectively. Furthermore, the accuracy of airway ultrasound in predicting endotracheal tube size was consistently higher than traditional methods, such as height formula, age formula, and the width of the little finger. In conclusion, airway ultrasound has unique advantages for confirming successful endotracheal intubation in pediatric patients, and it may become an effective auxiliary tool in this field. There is a need to develop a unified airway ultrasound protocol to conduct clinical trials and practice in the future.

Neonatal and paediatric point-of-care ultrasound review

Purpose

Point-of-care ultrasound (POCUS) examinations for children and newborns are different from POCUS exams for adults due to dissimilarities in size and body composition, as well as distinct surgical procedures and pathologies in the paediatric patient. This review describes the major paediatric POCUS exams and how to perform them and summarizes the current evidence-based perioperative applications of POCUS in paediatric and neonatal patients.

Method

Literature searches using PubMed and Google Scholar databases for the period from January 2000 to November 2021 that included MeSH headings of [ultrasonography] and [point of care systems] and keywords including "ultrasound" for studies involving children aged 0 to 18 years.

Results

Paediatric and neonatal POCUS exams can evaluate airway, gastric, pulmonary, cardiac, abdominal, vascular, and cerebral systems.

Discussion

POCUS is rapidly expanding in its utility and presence in the perioperative care of paediatric and neonatal patients as their anatomy and pathophysiology are uniquely suited for ultrasound imaging applications that extend beyond the standard adult POCUS exams.

Conclusions

Paediatric POCUS is a powerful adjunct that complements and augments clinical diagnostic evaluation and treatment.

Choice of the correct size of endotracheal tube in pediatric patients

Selection and insertion of an endotracheal tube (ETT) of appropriate size for airway management during general anesthesia in pediatric patients is very important. A very small ETT increases the risk of inadequate ventilation, air leakage, and aspiration, whereas a very large ETT may cause serious complications including airway damage, post-intubation croup, and, in severe cases, subglottic stenosis. Although the pediatric larynx is conical, the narrowest part, the rima glottidis, is cylindrical in the anteroposterior dimension, regardless of development, and the cricoid ring is slightly elliptical. A cuffed ETT reduces the number of endotracheal intubation attempts, and if cuff pressure can be maintained within a safe range, the risk of airway damage may not be greater than that of an ETT without cuff. The age-based formula suggested by Cole (age/4 + 4) has long been used to select the appropriate ETT size in children. Because age-based formulas in children are not always accurate, various alternative methods for estimating the ETT size have been examined and suggested. Chest radiography, ultrasound, and a three-dimensional airway model can be used to determine the appropriate ETT size; however, there are several limitations.

Ultrasonography measurement of glottic transverse diameter and subglottic diameter to predict endotracheal tube size in children: a prospective cohort study

We aimed to determine the correlation between mid-glottic transverse diameter/subglottic diameter and outer diameter of endotracheal tube (ETT) by ultrasonography in children. Ninety-five patients aged 1–8 years who underwent general anesthesia were included. Ultrasonography of glottic/subglottic transverse diameter was performed by two investigators after patients were anesthetized and when the train of four showed ≤ 4. The subglottic diameter was measured at the mid cricoid cartilage. The mid-glottic transverse diameter was measured at the mid-point of true vocal fold triangle whereas the distance between arytenoids was considered as the glottic transverse diameter. Linear regression models and correlation coefficients (r) were used to determine the best formula of glottic/subglottic transverse diameter to predict the outer diameter of ETT. The predicted outer diameter of ETT formula for subglottic diameter, mid-glottic transverse diameter, and glottic transverse diameter were 5.7 + (subglottic_mm/3) with an r of 0.45, 5.5 + (midglottic_mm/2) with an r of 0.47, and 5.7 + (glottic_mm/4) with an r of 0.46, respectively. The correlation between subglottic diameter and mid-glottic transverse diameter was 0.50. Subglottic/mid-glottic/glottic transverse diameter formulae had moderate correlations with the outer diameter of ETT. The glottic/mid-glottic transverse diameter can be used alternatively to predict the ETT size.

Trial registration: Thai Clinical Trial Registry: TCTR20191022002 Registered 22/10/2019—Prospectively registered, https://www.thaiclinicaltrials.org/# TCTR20191022002.

Challenge of Lung Isolation in Patients with Vocal Cord Implants

Glottic closure insufficiency increases the risk of aspiration and pneumonia, particularly in the elderly. Medialization thyroplasty is an open surgical procedure for treating glottic incompetency by approximating both vocal folds. The vocal fold medialization is achieved by inserting an implant to bring the nonmobile fold to the unaffected side. Lung isolation in patients with vocal cord implantation poses a unique challenge. Understanding the risks of different modalities of lung isolation and their impacts on the vocal cord implant is crucial to implementing a specifically tailored plan. Preoperative bronchoscopy, intraoperative video laryngoscopy, and bronchoscopy are ideal methods for assessing the vocal fold implants and guiding the lung isolation technique. Bronchial blocker through a single-lumen endotracheal tube may be the preferred choice to avoid the injury of the stretched vocal cords and dislodgement of the implant by a larger diameter double-lumen tube.

Length of the middle finger of hand as a simple and reliable predictor of optimal size of uncuffed endotracheal tube in paediatric patients: An observational study

Background and Aims

A recent study suggested middle finger length-based formula as a better predictive guide compared with age-based formula for selecting uncuffed endotracheal tubes (ETTs) in children. But that study did not meet sample size requirement. Thus, we primarily aimed to determine the accuracy of formula using length of the middle finger to determine the internal diameter of the uncuffed ETT and to compare its accuracy with the Cole's formula. As a secondary objective, we desired to compare its accuracy with some commonly used length and weight-based formulae.

Methods

This prospective observational study included children aged up to 12 years posted for elective surgery under general anaesthesia. The length of the middle finger on the palmar aspect of the hand was measured in the preoperative period and the characteristics of the airway used were noted. A predefined criterion of optimal size of the uncuffed ETT was used.

Results

A total of 139 patients were included in the final analysis. It was observed that the formula based on middle finger length can predict the optimal size of uncuffed ETT within an error of 0.5 mm in more than 90% instances and its predictive performance is better than Cole's formula. As a secondary outcome, we also observed that its accuracy is better than other formulae under evaluation.

Conclusion

Formula based on middle finger length can be used as a predictor of optimal size of uncuffed ETT in paediatric patients and it is a better predictor than Cole's formula.

Prediction of endotracheal tube size in pediatric patients: Development and validation of machine learning models

OBJECTIVE

We aimed to construct and validate machine learning models for endotracheal tube (ETT) size prediction in pediatric patients.

METHODS

Data of 990 pediatric patients underwent endotracheal intubation were retrospectively collected between November 2019 and October 2021, and separated into cuffed and uncuffed endotracheal tube subgroups. Six machine learning algorithms, including support vector regression (SVR), logistic regression (LR), random forest (RF), gradient boosting tree (GBR), decision tree (DTR) and extreme gradient boosting tree (XGBR), were selected to construct and validate models using ten-fold cross validation in training set. The optimal models were selected, and the performance were compared with traditional predictive formulas and clinicians. Furthermore, additional data of 71 pediatric patients were collected to perform external validation.

RESULTS

The optimal 7 uncuffed and 5 cuffed variables were screened out by feature selecting. The RF models had the best performance with minimizing prediction error for both uncuffed ETT size (MAE = 0.275 mm and RMSE = 0.349 mm) and cuffed ETT size (MAE = 0.243 mm and RMSE = 0.310 mm). The RF models were also superior in predicting power than formulas in both uncuffed and cuffed ETT size prediction. In addition, the RF models performed slightly better than senior clinicians, while they significantly outperformed junior clinicians. Based on SVR models, we proposed 3 novel linear formulas for uncuffed and cuffed ETT size respectively.

CONCLUSION

We have developed machine learning models with excellent performance in predicting optimal ETT size in both cuffed and uncuffed endotracheal intubation in pediatric patients, which provides powerful decision support for clinicians to select proper ETT size. Novel formulas proposed based on machine learning models also have relatively better predictive performance. These models and formulas can serve as important clinical references for clinicians, especially for performers with rare experience or in remote areas.

Prediction of endotracheal tube size in the pediatric age group by ultrasound: A systematic review and meta-analysis

Anatomical differences in the airway in pediatric patients, compared to adults pose many challenges during endotracheal intubation, such as selecting the proper sized endotracheal tube (ETT) during intubation. Our primary objective was to assess how accurate is ultrasound (US) co-relation in comparison to standard age-based formulas in pediatric patients. Meta-analysis was registered in PROSPERO 2020, CRD42020220041. Online literature available in PubMed, Cochrane, and Embase, Goggle scholar was searched from year 2000 till November 30, 2020, using relevant Mesh terms, ('airway US' OR (('airway'/exp OR airway) AND ('US'/exp OR US))) AND ('endotracheal intubation'/exp OR 'endotracheal intubation') AND ('pediatric'/exp OR pediatric)" to Predict endotracheal tube size/placement in pediatric age (neonate till 18 years) by the US. Bibliographic cross-references of selected publications were further manually screened. The full texts of each article were studied, once the abstract was found appropriate independently by two reviewers. A total of 48 papers published between 2010 and 2020 were identified as relevant and read in detail. Average numbers of patients were 86 and total numbers of patients were 1978. Most of the studies included pediatric patients posted for elective surgeries under general anesthesia and excluded emergency procedures, known laryngeal or tracheal pathology, high-risk patients, recent upper respiratory tract infections or allergy to ultrasound gel. A total of 18 independent correlations were analyzed. Final combined r value calculated from all the included articles was 0.824 (95% CI 0.677, 0.908) with a P < 0.00001 {strong co-relation (r > 0.80)}. Q statistic of 756.484, and I² statistics of 97.53% showed a large degree of heterogeneity in the effect size across the studies. Use of US for upper airway in pediatric patients is an effective modality and can effectively predict endotracheal tube size estimations in comparison to standard age-based or height-based formulae in the pediatric age group. US is a non-invasive, cost-effective, portable, and reproducible technique as compared to CT and MRI. It also takes less time with increasing expertise and experience.

Impact of endotracheal tube size and cuff pressure on tracheal and laryngeal mucosa of adult horses

OBJECTIVE

To assess the effects of two sizes of silicone endotracheal tubes with internal diameter 26 mm (ETT₂₆) and 30 mm (ETT₃₀) inflated to minimum occlusive volume on tracheal and laryngeal mucosa of adult horses anesthetized for 2 hours with isoflurane.

STUDY DESIGN

Prospective, randomized, blinded, crossover experimental study.

ANIMALS

A total of eight healthy adult mares.

METHODS

Upper airway endoscopy and ultrasound measurements of internal tracheal diameter were performed the day before anesthesia. Horses were anesthetized and orotracheally intubated with ETT₂₆ or ETT₃₀. Ease of intubation was scored. The cuff was inflated in 10 mL increments to produce a seal. Final volume of air used and intracuff (IC) pressure (measured by pressure transducer) were recorded. At the end of anesthesia, a manometer was used to measure IC pressure and these measurements compared against measurements from the pressure transducer. Laryngeal and tracheal mucosa were assessed via endoscopy and assigned a score 0-3 before anesthesia, and at 2 and 24 hours following extubation.

RESULTS

Data are from seven horses because one horse with laryngeal hemiplegia was excluded. Mean tracheal ultrasound measurement was 3.5 ± 0.4 cm. No significant differences were noted between endotracheal tube sizes for intubation score, IC pressures, inflation volumes or tracheal or laryngeal injury scores at any time point. IC pressure measured by manometer was slightly higher than that by transducer (+1.0 ± 2.8 mmHg).

CONCLUSIONS AND CLINICAL RELEVANCE

Results identified no clear advantage of one endotracheal tube size over the other in the population of horses studied, when endotracheal intubation is properly applied and IC pressure is carefully monitored. However, given that ETT₂₆ was associated with the highest observed IC pressures and the only observed incidents of tracheal circumferential erythema, the larger ETT₃₀ may be the better choice in most cases where tracheal size is sufficient.

Procedural Applications of Point-of-Care Ultrasound in Pediatric Emergency Medicine

Point-of-care ultrasound can improve efficacy and safety of pediatric procedures performed in the emergency department. This article reviews ultrasound guidance for the following pediatric emergency medicine procedures: soft tissue (abscess incision and drainage, foreign body identification and removal, and peritonsillar abscess drainage), musculoskeletal and neurologic (hip arthrocentesis, peripheral nerve blocks, and lumbar puncture), vascular access (peripheral intravenous access and central line placement), and critical care (endotracheal tube placement, pericardiocentesis, thoracentesis, and paracentesis). By incorporating ultrasound, emergency physicians caring for pediatric patients have the potential to enhance their procedural scope, confidence, safety, and success.

Prediction of endotracheal tube size using a printed three-dimensional airway model in pediatric patients with congenital heart disease: a prospective, single-center, single-group study

Background

To determine the correct size of endotracheal tubes (ETTs) for endotracheal intubation of pediatric patients, new methods have been investigated. Although the three-dimensional (3D) printing technology has been successful in the field of surgery, there are not many studies in the field of anesthesia. The purpose of this study was to evaluate the accuracy of a 3D airway model for prediction of the correct ETT size, and compare the results with a conventional age-based formula in pediatric patients.

Methods

Thirty-five pediatric patients under six years of age who were scheduled for congenital heart surgery were enrolled. In the pre-anesthetic period, the patient’s computed tomography (CT) images were converted to Standard Triangle Language (STL) files using the 3D conversion program. A Fused Deposition Modelling (FDM) type 3D printer was used to print 3D airway models from the sub-glottis to the upper carina. ETT size was selected by inserting various sized cuffed-ETTs to a printed 3D airway model.

Results

The 3D method selected the correct ETT size in 21 out of 35 pediatric patients (60%), whereas the age-based formula selected the correct ETT size in 9 patients (26%).

Conclusions

Prediction of the correct size of ETTs using a printed 3D airway model demonstrated better results than the age-based formula. This suggests that the selection of ETT size using a printed 3D airway model may be feasible for helping minimize re-intubation attempts and complications in patients with congenital heart disease and/or those with an abnormal range of growth and development.

Ultrasonography for airway management

Ultrasonography (USG) allows a new approach to the airway in anaesthesia and intensive care. USG visualises the airway from the mouth to the lungs. By exploring the entire airway, USG proposes new criteria (1) to assess the risk of difficult laryngoscopy, (2) to anticipate the management of a difficult airway, (3) to confirm the position of the endotracheal tube (ETT), and (4) to confirm that the lungs are effectively ventilated. Intraoperatively, USG may also help to resolve acute ventilatory problems such as pneumothorax, delayed selective bronchial intubation after patient positioning (Trendelenburg, prone or lateral position) or acute pulmonary oedema.

Comparison of Endoscopic and Ultrasonographic Measurements of the Subglottic Airway in Children

OBJECTIVE

To compare measurements of the pediatric subglottis obtained by surgeon-performed ultrasound and endoscopy.

STUDY DESIGN

Prospective observational comparison-of-methods study.

SETTING

Tertiary care pediatric hospital.

SUBJECTS AND METHODS

Thirty-one patients who underwent direct laryngoscopy from May 2017 to July 2018 were recruited. Transcervical ultrasound was used to visualize the vocal folds, subglottis, and cervical trachea. The anterior-posterior (AP) and transverse (TV) diameter of the subglottic space were measured endoscopically and via ultrasound by 2 independent evaluators. Measurements were compared for correlation, bias, and agreement. A clinically acceptable bias for subglottic diameter was assumed to be 0.5 mm or less.

RESULTS

The median age of enrolled patients was 2.6 years (range, 4 months-13.3 years). Endoscopic subglottic AP and TV measurements ranged from 3.33 mm to 14.81 mm and from 4.44 mm to 11.65 mm, respectively, while ultrasonographic AP and TV measurements ranged from 4.57 mm to 9.85 mm and from 3.77 mm to 8.96 mm. Pearson coefficient showed strong a correlation for both endoscopic and ultrasound AP (R = 0.8081, P < .0001) and TV (R = 0.8796, P < .001) measurements of the subglottis. Bland-Altman plots revealed a bias (average discrepancy) for AP measurements of 0.22 mm and 0.11 mm for TV measurements.

CONCLUSION

Endoscopic and ultrasonography measurements of the pediatric subglottic airway were strongly correlated. The discrepancy between AP and TV measurements was less than 0.5 mm. Ultrasound of the subglottis may be an alternative to endoscopic assessment of the airway for measurement of the subglottic airway in children in select cases.

The development of the cricoid cartilage and its implications for the use of endotracheal tubes in the pediatric population

BACKGROUND

The rigid cricoid cartilage is functionally the narrowest portion of the larynx. There is some controversy over the shape of the pediatric cricoid cartilage in the transverse plane. It is important to understand the development of the cricoid cartilage so that endo-traceheal tubes can be used more safely.

AIM

To determine changes in the internal diameter and shape of the cricoid cartilage during development and explore the implications of those changes for the selection of ETT type and size for children.

METHODS

The cervical computed tomography scans were reviewed in patients aged 1-20 years. After performing the multiplanar reconstruction and correcting the slant, the transverse and anteroposterior internal diameters of the inlet and outlet of the cricoid cartilage were measured, respectively. The angle between the arch and the lamina of the cricoid cartilage in the middle sagittal plane was measured. The ratios of transverse to anteroposterior diameter for the inlet and outlet of the cricoid cartilage were calculated, respectively.

RESULTS

In females, the internal diameters of the cricoid cartilage increased linearly with age. In males, the internal diameters of the cricoid cartilage exhibited a growth spurt during adolescence. The transverse diameter of the inlet was the smallest diameter of the cricoid cartilage, and the predicting formula of the transverse diameter of the inlet for children aged 1-12 was 0.4 × age (year) + 5.1, R²  = .758. The angle between the arch and lamina of the cricoid cartilage and the ratios of transverse to anteroposterior diameter correlated weakly with age.

CONCLUSION

The transverse inner diameter of the inlet is the smallest diameter of the cricoid cartilage. The "funnel shape" of the cricoid cartilage remains unchanged during development. The outer diameter should be considered when selecting an endotracheal tube.

Learning curve of ultrasound measurement of subglottic diameter for endotracheal tube selection in pediatric patients

BACKGROUND

Endotracheal tube size can be predicted according to ultrasound measurement of subglottic airway diameter. The learning curve for this method is not yet established. The aim was to evaluate the learning curve of anesthesiology residents in ultrasound measurement of subglottic airway diameter for prediction of endotracheal tube size using cumulative sum analysis.

METHODS

Sixteen anesthesiology residents measured transverse subglottic airway diameter in children undergoing general anesthesia with cuffed endotracheal intubation. Each resident performed 30 ultrasound examinations. Primary outcome was the successful prediction of endotracheal tube size according to ultrasound measurement. Cumulative sum analysis was performed with acceptable and unacceptable failure rates set as 20 and 40%, respectively.

RESULTS

Ten out of 16 residents (62.5%) were deemed successful as they were able to pass lower decision boundary, whereas six residents' CUSUM scores were between the decisions lines deeming them indeterminate. The overall success rate for determining the correct endotracheal tube size was 77.5%. Median number of attempts to cross lower decision boundary was 29 with minimum of 18 and maximum of 29 attempts among successful residents.

CONCLUSION

Learning curves constructed with cumulative sum analysis in this study showed that only 62.5% of residents were able to correctly predict cuffed endotracheal tube size with 80% success rate. Considerable variability in achieving competency necessitates objective follow-up of individual improvement.

New directions in point-of-care ultrasound at the crossroads of paediatric emergency and critical care

PURPOSE OF REVIEW

The diagnostic capability, efficiency and versatility of point-of-care ultrasound (POCUS) have enabled its use in paediatric emergency medicine (PEM) and paediatric critical care (PICU). This review highlights the current applications of POCUS for the critically ill child across PEM and PICU to identify areas of progress and standardized practice and to elucidate areas for future research.

RECENT FINDINGS

POCUS technology continues to evolve and advance bedside clinical care for critically ill children, with ongoing research extending its use for an array of clinical scenarios, including respiratory distress, trauma and dehydration. Rapidly evolving and upcoming applications include diagnosis of pneumonia and acute chest syndrome, identification of intra-abdominal injury via contrast-enhancement, guidance of resuscitation, monitoring of increased intracranial pressure and procedural guidance.

SUMMARY

POCUS is an effective and burgeoning method for both rapid diagnostics and guidance for interventions and procedures. It has clinical application for a variety of conditions that span PEM and PICU settings. Formal POCUS training is needed to standardize and expand use of this valuable technology by PICU and PEM providers alike.

Point-of-care ultrasound in pediatric anesthesiology and critical care medicine

Ultrasound has increasingly become a clinical asset in the hands of the anesthesiologist and intensivist who cares for children. Though many applications for ultrasound parallel adult modalities, children as always are not simply small adults and benefit from the application of ultrasound to their management in various ways. Body composition and size are important factors that affect ultrasound performance in the child, as are the pathologies that may uniquely afflict children and aspects of procedures unique to this patient population. Ultrasound simplifies vascular access and other procedures by visualizing structures smaller than those in adults. Maturation of the thoracic cage presents challenges for the clinician performing pulmonary ultrasound though a greater proportion of the thorax can be seen. Moreover, ultrasound may provide unique solutions to sizing the airway and assessing it for cricothyroidotomy. Though cardiac ultrasound and neurosonology have historically been performed by well-developed diagnostic imaging services, emerging literature stresses the utility of clinician ultrasound in screening for pathology and providing serial observations for monitoring clinical status. Use of ultrasound is growing in clinical areas where time and diagnostic accuracy are crucial. Implementation of ultrasound at the bedside will require institutional support of education and credentialing. It is only natural that the pediatric anesthesiologist and intensivist will lead the incorporation of ultrasound in the future practice of these specialties.