Endotracheal Tube Size Research Articles

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

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. 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 sumanalysis was performed with acceptable and unacceptable failure rates set as 20 and 40%, respectively. 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. Learning curves constructed with cumulative sumanalysis 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.

Development of a clinical tool to aid endotracheal tube size selection in dogs

ObjectiveTo identify phenotypic parameters correlating with the inner tracheal diameter (ITD) and endotracheal tube size (ETS) in adult dogs and to develop a chart for ETS estimation.MethodsFive-hundred and forty-four adult...

Respiratory acidosis during bronchoscopy-guided percutaneous dilatational tracheostomy: impact of ventilator settings and endotracheal tube size

BackgroundThe current study investigates the effect of bronchoscopy-guided percutaneous dilatational tracheostomy (PDT) on the evolution of respiratory acidosis depending on endotracheal tube (ET) sizes. In addition, the impact of increasing tidal volumes during the intervention was investigated.MethodsTwo groups of ICU-patients undergoing bronchoscopy-guided PDT with varying tidal volumes and tube sizes were consecutively investigated: 6 ml/kg (N = 29, mean age 57.4 ± 14.5 years) and 12 ml/kg predicted body weight (N = 34, mean age 59.5 ± 12.8 years).ResultsThe mean intervention time during all procedures was 10 ± 3 min. The combination of low tidal volumes and ETs of 7.5 mm internal diameter resulted in the most profound increase in PaCO2 (32.2 ± 11.6 mmHg) and decrease in pH-value (− 0.18 ± 0.05). In contrast, the combination of high tidal volumes and ETs of 8.5 mm internal diameter resulted in the least profound increase in PaCO2 (8.8 ± 9.0 mmHg) and decrease of pH (− 0.05 ± 0.04). The intervention-related increase in PaCO2 was significantly lower when using higher tidal volumes for larger ET: internal diameter 7.5, 8.0 and 8.5: P > 0.05, =0.006 and = 0.002, respectively. Transcutaneous PCO2 monitoring revealed steadily worsening hypercapnia during the intervention with a high correlation of 0.87 and a low bias of 0.7 ± 9.4 mmHg according to the Bland-Altman analysis when compared to PaCO2 measurements.ConclusionsProfound respiratory acidosis following bronchoscopy-guided PDT evolves in a rapid and dynamic process. Increasing the tidal volume from 6 to 12 ml/kg PBW was capable of attenuating the evolution of respiratory acidosis, but this effect was only evident when using larger ETs.Trial registrationDRKS00011004. Registered 20th September 2016.

Focused airway ultrasound: an armamentarium in future airway management

Point-of-care ultrasound (POCUS) has gained the upper hand for being simple, non-invasive and portable. Traditional beliefs that ultrasound is futile in the imaging of air-filled structures has been refuted. Upper airway ultrasound is applicable to patients with distorted anatomy, not easily discernable by traditional methods, besides serving as a useful adjunct peri-intubation; as a pre-intubation screening tool for difficult laryngoscopy, selection of endotracheal tube (ETT) size and confirmation of ETT placement and depth, and to detect laryngeal mask airway (LMA) malrotation. Airway ultrasound also assists in procedural guidance for percutaneous cricothyroidotomy, percutaneous dilatational tracheostomy (PDT) and airway nerve blocks by improving success rate with fewer attempts and safety. In the critical care unit, sonographic parameters of the airway provide means to predict post extubation stridor hence successful extubation, in addition to identifying upper airway pathologies. The feasibility of focused airway ultrasound also lies in its shallow learning curve and the relative ease of mastering the skill with appropriate training. The integration of upper airway ultrasound into POCUS examination may be a prelude to a bigger picture in future airway management. Increasing awareness of the practicality of this tool, availability in critical areas and improving technological advancements will encourage more usage resulting in its incorporation into routine clinical practice.

Tracheal Size and Morphology on the Reconstructed CT Imaging.

To characterize the real size and morphology of tracheas in childhood for the optimal selection of endotracheal tube. A retrospective cohort study of pediatric patients who received CT scan of the cervical spine from July 2011 to March 2018. Cross-sectional CT images vertical to trachea were reconstructed and the accurate tracheal diameters were measured. The validity of the traditional age-based formula for predicting the endotracheal tube size was assessed for the best fit to trachea. Tertiary Emergency and Critical Care Center of Kyushu University Hospital. Children, who are 1 month to 15 years old, received CT scan of the cervical spine. None. We enrolled 86 children with median age of 53 months. The cross-sectional shape of pediatric trachea was circular at the cricoid level and elliptical at the infraglottic level. The narrowest part of pediatric trachea was the transverse diameter at the infraglottic level at any age. Significant positive correlation between age and the narrowest diameter was observed. When compared the transverse diameter at the infraglottic level with the outer diameter of endotracheal tubes, uncuffed endotracheal tubes selection based on the traditional age-based formula ran a significant risk of oversized endotracheal intubation until 10 years old compared with cuffed endotracheal tubes selection (60.0% vs 23.8%; p < 0.05). These findings indicate the safety and efficacy of cuffed endotracheal tubes in infants and children and the reconsideration for the airway management in pediatric anesthesia and intensive care.

The effect of pressure support on imposed work of breathing during paediatric extubation readiness testing

BackgroundPaediatric critical care practitioners often make use of pressure support (PS) to overcome the perceived imposed work of breathing (WOBimp) during an extubation readiness test (ERT). However, no paediatric data are available that shows the necessity of adding of pressure support during such tests. We sought to measure the WOBimp during an ERT with and without added pressure support and to study its clinical correlate. This was a prospective study in spontaneously breathing ventilated children < 18 years undergoing ERT. Using tracheal manometry, WOBimp was calculated by integrating the difference between positive end-expiratory pressure (PEEP) and tracheal pressure (Ptrach) over the measured expiratory tidal volume (VTe) under two paired conditions: continuous positive airway pressure (CPAP) with and without PS. Patients with post-extubation upper airway obstruction were excluded.ResultsA total of 112 patients were studied. Median PS during the ERT was 10 cmH2O. WOBimp was significantly higher without PS (median 0.27, IQR 0.20–0.50 J/L) than with added PS (median 0.00, IQR 0.00–0.11 J/L). Although there were statistically significant changes in spontaneous breath rate [32 (23–42) vs. 37 (27–46) breaths/min, p < 0.001] and higher ET-CO2 [5.90 (5.38–6.65) vs. 6.23 (5.55–6.94) kPa, p < 0.001] and expiratory Vt decreased [7.72 (6.66–8.97) vs. 7.08 (5.82–8.08) mL/kg, p < 0.001] in the absence of PS, these changes appeared clinically irrelevant since the Comfort B score remained unaffected [12 (10–13) vs. 12 (10–13), P = 0.987]. Multivariable analysis showed that changes in WOBimp occurred independent of endotracheal tube size.ConclusionsWithholding PS during ERT does not lead to clinically relevant increases in WOBimp, irrespective of endotracheal tube size.

Factors influencing the accuracy of ETT size prediction in children with CHD: a pilot study

Induction and intubation for pediatric patients with congenital heart defects (CHD) should be conducted with careful measures to avoid any complications due to anesthetic drugs. Proper endotracheal tube (ETT) size is essential to avoid reintubation. The aim of this study is to analyze factors affecting the accuracy of uncuffed ETT size prediction in paediatrics with CHD. This observational-analytic study included seventeen patients aged 0-8 years with CHD underwent general anesthesia with tracheal intubation. Subjects were classified as cyanotic or acyanotic heart disease. The ETT size was predicted by Cole’s formula. The accuracy of prediction was analyzed according to age, body weight, height and type of CHD. The prediction of ETT size was accurate in 53% of the subjects. The prediction was inaccurate in 63% of cyanotic subjects, while only 16.7% of acyanotic subjects. Univariate analysis for all variables showed there was no significant factor to affect the accuracy of ETT size prediction. The smallest p value was subject’s height. Height has a 69.8% affecting factor to predict the accurate ETT size. Thus, age, body weight, height and type of CHD are not statistically significant factors to affect the accuracy of ETT size prediction. But, height gives a better prediction to the accuracy of ETT size.

A retrospective analysis of factors associated with difficult endotracheal tube passage with use of the hyper-angled GlideScope blade

Introduction: Videolaryngoscopy is a valuable tool for tracheal intubation. Some videolaryngoscopes such as the GlideScope, use a hyper-angled blade to improve the glottic view. Despite improved visualization, difficulty during GlideScope laryngoscopy may occur during manipulation of the endotracheal tube (ETT). This investigation seeks to identify characteristics and procedural factors associated with difficult or failed ETT passage. Methods: A single institution retrospective cohort analysis was performed for adult GlideScope intubations utilizing a hyper-angled blade. Tube passage was recorded as easy (T1), difficult (T2), or failed (T3). The primary outcome was difficult or failed ETT passage. A nonparsimonious logistic regression model was developed to determine independent predictors of this outcome, with an exploratory analysis conducted by bootstrapping the data across 1000 samples. Subgroup analysis was performed for head and neck surgical cases. Results: A total of 6109 patients met inclusion criteria. In all, 5412 (88.6%) had easy ETT passage, 666 (10.9%) difficult, and 31 (0.5%) failed. Limited view (grades 2a, 2b, 3, and 4) and short thyromental distance (&lt;6 cm) were independent predictors of difficulty or failure. The absence of teeth and use of standard oral ETT sizes 6–8 were negative predictors (protective) for difficulty or failure. In the subgroup analysis, use of laser-safe ETTs also independently predicted difficulty or failure. Conclusions: A relatively high incidence of difficulty during tracheal tube passage using GlideScope hyper-angled blades was observed. Limited videolaryngoscopic view, short thyromental distance, and use of nonstandard ETTs were independent predictors of procedural difficulty.

Rule of 4's: Safe and effective pleural decompression and chest drain insertion in severely injured children.

The intersecting scenarios of multi-trauma, thoracic injury and traumatic cardiac arrest present some of the most demanding moments in paediatric trauma. For these reasons, decision support through teamwork, checklists, technology and guidelines are central to ensuring quality paediatric trauma care. The 'Rule of 4's' is a simple aide-memoire, which guides clinicians of all grades, expertise and distractedness in a reliable approach to injured children who require safe and effective emergency pleural decompression and timely insertion of a chest drain. The Rule of 4's enables these important therapeutic goals to be met through: (i) four steps in a 'good plan'; (ii) fourth (or fifth) intercostal space as the basis for siting a 'good hole'; (iii) 4× uncuffed endotracheal tube size (4× [age/4 + 4]) to guide selection of a 'good tube'; and (iv) 4 cm mark for a 'good stop' to ensure the drain is in far enough but not too far.

Improving Simulated Pediatric Airway Management in Community Emergency Departments Using a Collaborative Program With a Pediatric Academic Medical Center.

Pediatric airway management is a challenging process at community emergency departments (CEDs) due to lower pediatric volume, a lack of pediatric expertise among staff, and a lack of pediatric-specific equipment and resources. This has contributed to increased mortality in pediatric patients presenting to CEDs in comparison to pediatric academic medical centers (AMCs). We hypothesized that a collaborative program between CEDs and the state AMC would improve the quality of pediatric airway management provided by CEDs in simulated settings and the CEDs' pediatric emergency readiness scores. This prospective, pre- and post-intervention study utilized in situ simulation and was conducted in 10 CEDs in the state of Indiana. A team from the pediatric AMC led a multi-faceted improvement program, which included post-simulation debriefing, addressing pediatric airway management issues, targeted assessment reports, access to pediatric resources, and ongoing communication with the AMC. The primary outcome of the study was improvement of simulated pediatric airway management in the CEDs. The secondary outcome was improvement of the CEDs' pediatric emergency readiness scores score. A total of 35 multidisciplinary teams participated in pre-intervention sessions, and 40 teams participated in post-intervention sessions. Overall adherence to a critical action checklist improved from 52% at the pre-intervention visits to 71% post-intervention (P = .003). There were significant improvements in the use of appropriate endotracheal tube (ETT) size (from 67% to 100%, P = .02), cuffed ETT (from 8% to 71%, P < .001), appropriate blade size (from 58% to 100%, P = .03), and availability of suction catheter (from 10% to 42%, P = .049). The CEDs' total pediatric emergency readiness scores score improved from 58.8 ± 15.6 pre-intervention to 75.8 ± 9.3 post-intervention (P = .01). A collaborative improvement program between a pediatric AMC and CEDs improved the CEDs' simulated pediatric emergency airway management. This model can be utilized to improve management of other pediatric critical conditions in these CEDs.

Routine use of ultrasonography in prediction of uncuffed endotracheal tube size in pediatric patients

Background and aimsEndotracheal intubation is a crucial skill in anesthesia. Uncuffed pediatric endotracheal tube (ETT) size can be calculated by various methods like age-based formula or by using ultrasound to measure minimal transverse subglottic diameter (MTSD). This study aimed to compare both age-based formula and ultrasound to assess the advantage of routine use of ultrasound to determine pediatric ETT size.Materials and methodsForty children of 2–10 years of age, ASA class ≤ II, Mallampati airway classes I and II, scheduled for surgery away from the head and neck, were included. Uncuffed ETT size for each child was calculated using age-based formula. After induction of balanced general anesthesia, an ultrasound was done to measure MTSD and an endotracheal tube was selected accordingly. After intubation, an air leak test was done and the ETT was accordingly changed (if needed).ResultsETT size by age-based formula strongly correlated with the size measured by ultrasound (Pearson correlation 0.913; P < 0.001). The percentage of the need to change the endotracheal tube according to the leak test was only 7.5%.ConclusionThe ETT size calculation was similar for both age-based formula and ultrasound. So, we could not justify the routine use of ultrasound for calculating ETT size for intubation in pediatric patients.

Voice loss following endotracheal intubation: The anaesthesiologist's dilemma

Endotracheal intubation is a routine procedure performed by anaesthesiologists worldwide. It is as routine as the placement of a peripheral intravenous catheter. Albeit the gold standard for securing the airway, endotracheal intubation comes with it's share of adverse effects, one of the worst being loss of voice or aphonia. A literature search in major medical databases revealed useful information about the aetiopathogenesis, various mechanisms and risk factors leading to vocal symptoms and acoustic variations. Patient risk factors such as age and co-morbid conditions and anaesthetic considerations such as size of endotracheal tube, number of attempts, mean cuff pressure, anaesthetic agents used and nature and duration of surgery all seem to have a role in this intriguing problem. This review also includes cases we have personally come across in our practice. Based on our experience of cases that we have come across, we propose an algorithm to avoid such a problem.

Prediction of endotracheal tube size in children by predicting subglottic diameter using ultrasonographic measurement versus traditional formulas.

Background:Paediatric airway assessment remains the most challenging task before the anaesthesiologists. Recent advancement in ultrasonography techniques should now allow for accurate and descriptive evaluation of paediatric airway. To compare calculated external diameters of the endotracheal tube from physical indices of traditional formulas and predetermined by ultrasound.Materials and Methods:100 subjects of either sex between 12-60 months of age, undergoing various elective surgeries under general anaesthesia requiring endotracheal intubation were enrolled in the study. The transverse diameter was measured at the level of cricoids cartilage by ultrasonography. The tracheal tube was considered best fit if air leak was satisfactory at 15-20 cm H2O of airway pressure. The obtained values were compared with the values of endotracheal tube size calculated by various age, height, weight based formulas and diameter of right and left little finger. The correlation of size of Endotracheal tube by different modalities was done and Pearson's correlation coefficient was obtained.Results:According to Pearson's correlation there was a moderate correlation of best fit Endotracheal tube with endotracheal tube size by age based formula (r = 0.743), body length based formula (r = 0.683), right little finger based formula (r = 0.587), left little finger based formula (r = 0.587) and multivariate formula (r = 0.741). There was a strong correlation with ultrasonography (r = 0.943).Conclusion:Ultrasonography is a reliable method of estimation of subglottic diameter and for prediction of endotracheal tube size in children.

A new second-generation supraglottic airway device (Ambu® AuraGain•) versus intubating laryngeal mask airway as conduits for blind intubation - A prospective, randomised trial.

Background and Aims:The Ambu® AuraGain• is a new single-use supraglottic airway device with gastric channel, designed to facilitate intubation. The study aimed to assess the success rates of proper placement and intubation using Ambu® AuraGain• compared with intubating laryngeal mask airway (ILMA).Methods:One hundred and twenty patients (18–60 years) were enrolled into this prospective, randomised, comparative study. After inducing general anaesthesia, appropriate size ILMA (group I)/Ambu® AuraGain• (group A) was placed as per the manufacturer's recommendations and correct placement was confirmed. Appropriate size endotracheal tube was passed through the device. The success rate of insertion and intubation, number of attempts, Cormack–Lehane grading before insertion and haemodynamics were recorded. Data were analysed using Mantel–Haenszel Chi-square test, Student's t-test and Fisher's exact test.Results:Demographic and airway parameters were uniformly distributed in both the groups. The success rate for insertion was 100% in both devices. The success rate for intubation was 96.6% (58/60) in group I and 36.6% in group A (P < 0.001). In group I, patients with mean thyromental distance >7.62 ± 0.75 cm had higher successful intubation compared with patients with mean thyromental distance <5.25 ± 0.35 cm (P = 0.014). Cormack–Lehane grading did not correlate with intubation attempts or success rate in group I (P = 0.45), whereas in group A the rate of successful blind intubation with Cormack–Lehane grade 1 was 50% (19/38).Conclusion:Both devices have 100% insertion success, though Ambu® AuraGain• has lower success rate for facilitating intubation compared with ILMA.

Assessment of the Subglottic Region for Estimation of Appropriate Size Endotracheal Tube in Pediatric Patient: Ultrasonography Versus Age Based Formula

Assessment of the Subglottic Region for Estimation of Appropriate Size Endotracheal Tube in Pediatric Patient: Ultrasonography Versus Age Based Formula

Prediction of paediatric micro-cuff endotracheal tube size by ultrasonography and its comparison to standard age-based formula

Prediction of paediatric micro-cuff endotracheal tube size by ultrasonography and its comparison to standard age-based formula

Radiological evaluation of airway - What an anaesthesiologist needs to know!

Airway management forms the foundation of any anaesthetic management. However, unanticipated difficult airway (DA) and its sequelae continue to dread any anaesthesiologist. In spite of development of various clinical parameters to judge DA, no single parameter has proved to be accurate in predicting it. Radiological evaluation may help assess the aspects of patient's airway not visualised through the naked eye. Starting from traditional roentgenogram to ultramodern three-dimensional printing, imaging may assist the anaesthesiologists in predicting DA and formulate plan for its management. Right from predicting DA, it has been used for estimating endotracheal tube sizes, assessing airway pathologies in paediatric patients and planning extubation strategies. This article attempts to provide exhaustive overview on radiological parameters which can be utilised by anaesthesiologists for prediction of DA.

Effect of Endotracheal Tube Size and Cuff Pressure on Incidence of Postoperative Sore Throat: Comparison between Three Facilities

Effect of Endotracheal Tube Size and Cuff Pressure on Incidence of Postoperative Sore Throat: Comparison between Three Facilities

Effect of endotracheal tube size and cuff pressure on incidence of postoperative sore throat: Comparison between three facilities

Effect of endotracheal tube size and cuff pressure on incidence of postoperative sore throat: Comparison between three facilities

Tracheal Diameter Estimates Using Age-Related Formula Versus Radiographic Findings: Which Approximates the Actual Tracheostomy Tube in Pediatric Patients?

Objective: To compare actual tracheostomy tube sizes with estimated endotracheal tube sizes using age-related formula and tracheal diameter from preoperative radiographs among pediatric Filipino patients aged 0-18 years old undergoing tracheostomy.&#x0D; Methods:&#x0D; Study Design: Review of records&#x0D; Setting: Tertiary Private University Hospital in Dasmarinas, Cavite, Philippines&#x0D; Patients: Pediatric patients regardless of gender, aged 0 to 18 years old, with a preoperative radiograph of the trachea, and who subsequently underwent tracheostomy anytime from January 1, 2007 to December 31, 2016 were considered for inclusion. Radiographs were measured, endotracheal tube sizes were computed using age-related formula, and recorded tracheotomy tube sizes were retrieved.&#x0D; Results: Twenty-two patients (12 males, 10 females) aged 10 months to 18-years-old (median age: 11 years) were included in the study. Mean tube sizes were 6.46mm (+/- 1.492 SD) for age-related formula, 5.67mm (+/- 1.1849 SD) for radiograph-based estimation, and 5.0 for actual tracheostomy tube inserted in each patient. The Bland-Altman plot showed the bias estimate at 0.7913 and the lower and upper limits of agreement at -1.3598 and 2.9423 (confidence level 95% or 2 standard deviations away from the mean).&#x0D; Conclusions: The average value derived from radiograph-based estimation is less than the corresponding average value from age-related formula. There is a significant difference between age-related formula-based estimation and actual tracheostomy tube inserted. Since the range of differences between the two estimation methods is high, these results imply that the bias or the difference between measures from the two methods is not consistent, with the two methods exhibiting very poor agreement.&#x0D; Keywords: Tracheostomy, Intubation, Intra Tracheal, Penlington Formula, Trachea Radiograph Measurement, age related formula for endotracheal tube estimation