Tracheal tube-tip displacement in children during head-neck movement—a radiological assessment †

Comparison of preformed microcuff and preformed uncuffed endotracheal tubes in pediatric cleft palate surgery-A randomized controlled trial

BACKGROUND AND AIMS

Airway management in children with oral cleft surgery carries unique challenges, concerning the proximity of the surgical site and the tracheal tube. We hypothesized that using a Microcuff oral RAE tube would reduce tube exchange and migration rate. We aimed to compare the performance of Microsoft and uncuffed oral performed tracheal tubes in children undergoing cleft palate surgeries regarding the rate of tracheal tube exchange, endobronchial intubation, and ventilatory parameters.

METHODS

One hundred children scheduled for cleft palate surgery were randomized into two groups. In the uncuffed group (n = 50), the tracheal tube was selected using the Modified Coles formula, and in the Microcuff (n = 50) group, the manufacturer's recommendations were followed. Intraoperatively, we compared the primary outcome of tube exchange using the chi-square test. The leak pressure and ventilatory parameters after head extension and mouth gag application were measured in both groups.

RESULTS

The tracheal tube exchange rate was significantly lower in the Microcuff group (0/50) than in uncuffed (19/50) preformed tubes (0 vs. 38% respectively; p <.001). The uncuffed and Microcuff tracheal tube were comparable concerning ventilation parameters and leak pressure of finally placed tubes (17.78 ± 3.95 vs. 19.26 ± 3.81 cm H2 O respectively, with a mean difference (95% CI) of -1.48 (-0.01-2.98); p-value =0.059. Cuff pressure did not vary significantly during the initial hour, and the incidence of postoperative airway morbidity between uncuffed and Microcuff tube was comparable, 5/50 (10%) versus 7/50 (14%) with risk ratio (95% CI) of 0.71(0.24-2.1), p value .49.

CONCLUSION

Microcuff oral preformed tubes performed better than uncuffed tubes regarding tube exchange during cleft palate surgery.

Usefulness of video laryngoscopy in tracheal intubation at thyroid surgical position for intraoperative neuromonitoring

This observational study aimed to compare the glottic view between video and direct laryngoscopy for tracheal intubation in the surgical position for thyroid surgery with intraoperative neuromonitoring. Patients scheduled for elective thyroid surgery with intraoperative neuromonitoring were enrolled. After the induction of anesthesia, patients were positioned in the thyroid surgical posture with a standard inclined pillow under their head and back. An investigator assessed the glottic view using the percentage of glottic opening (POGO) scale and the modified Cormack-Lehane grade in direct laryngoscopy and then video laryngoscopy sequentially while using the same McGRATH™ MAC video laryngoscope at once, with or without external laryngeal manipulation, at the surgical position. A total of thirty-nine patients were participated in this study. Without external laryngeal manipulation, the POGO scale significantly improved during video laryngoscopy compared to direct laryngoscopy in the thyroid surgical position (60.0 ± 38.2% vs. 22.4 ± 23.8%; mean difference (MD) 37.6%, 95% confidence interval (CI) = [29.1, 46.0], P < 0.001). Additionally, with external laryngeal manipulation, the POGO scale showed a significant improvement during video laryngoscopy compared to direct laryngoscopy (84.6 ± 22.9% vs. 58.0 ± 36.3%; MD 26.7%, 95% CI = [18.4, 35.0] (P < 0.001). The superiority of video laryngoscopy was also observed for the modified Cormack-Lehane grade. In conclusion, video laryngoscopy with the McGRATH™ MAC video laryngoscope, when compared to direct laryngoscopy with it, improved the glottic view during tracheal intubation in the thyroid surgical position. This enhancement may potentially facilitate the proper placement of the electromyography tracheal tube and prevent tube displacement due to positional change for thyroid surgery.

New Formula for Depth of Insertion of Endotracheal Tube in Children: A Prospective Observational Study

OBJECTIVES

To assess the correct placement of endotracheal tube (ETT) by confirming it with a flexible fiberoptic bronchoscope (FOB), to propose a new formula that would be suitable for Indian children, and to assess the movement of the ETT tip during neck flexion and extension.

METHODS

A total of 76 patients were included in the study between the age of 2 and 10 y. Depth of ETT insertion was assessed using FOB. ETT migration due to changes in head and neck position was also assessed.

RESULTS

It was observed that 6 out of 76 children had endobronchial/at carina position of ETT after the initial insertion as per the black line guidance in the neutral position. While the incidence was 23, 36, and 36, respectively as per Cole, weight-, and height-based formula.

CONCLUSION

The existing formulae are not suitable for Indian children as their physical stature is different from other ethnic populations. Therefore, the authors suggest a new formula [(Age/2) + 10 cm] for depth of ETT insertion for children of the authors' geographical area.

TRIAL REGISTRATION

CTRI/2015/06/005871.

A new formula to predict the size and insertion depth of cuffed nasotracheal tube in children receiving dental surgery: a retrospective study

This retrospective study aimed to develop a new formula for selecting the appropriate size and determining the depth of the cuffed nasotracheal intubation (NTI) for a cuffed endotracheal tube (cETT) in pediatric patients undergoing dental surgery. In addition, the clinical data on cETT (i.e., the size and depth of insertion) was compared with those calculated with age-based formulas to evaluate their correlation. A total number of 684 patients who received NTI were enrolled (healthy group, n = 607; special-need group, n = 77). The ETT size used in real-world scenarios was smaller (i.e., about 0.5 and 0.94 mm) than the age-based formula, while the ETT depth was greater (i.e., about 1.5 cm) than the age-based formula in both groups. In the healthy group, age, gender, and body weight were identified as predictors of ETT size and depth through multiple linear regression analysis, while only age and body weight were predictors in the special-needs group. New formulas were developed based on these findings, with ETT size = 3.98 + 0.052 × age + 0.048 × gender (male = 1, female = 0) + 0.023 × body weight (kg) and ETT depth = 15.1 + 0.43 × age + 0.300 × gender (male = 1, female = 0) + 0.007 × body weight (kg). The new formula could be useful for both healthy and special-need pediatric populations undergoing dental procedures.

Guedel oropharyngeal airway: The validation of facial landmark-distances to estimate sizing in children - Visualisation by magnetic resonance imaging (GUEDEL-I): A prospective observational study

OBJECTIVE

To validate the ERC-recommended facial landmark-distance for oropharyngeal airway sizing in children.

METHODS

We conducted a prospective observational study in anaesthetised, spontaneously breathing children ≤12 years undergoing cranial MRI. Oropharyngeal airways were inserted following the distance from the maxillary incisors to the mandibular angle. Primary outcome was the rate of properly sized oropharyngeal airways on MRI, defined as the distal end positioned within 10 mm from the epiglottis without contacting it. Secondary outcomes were the occurrence of tongue protrusion, oropharyngeal airways clinical efficacy, and related adverse events. Furthermore, we calculated probabilities for the estimation of proper size when considering five facial landmark-distances and optimal rules based on biometric parameters.

RESULTS

In 94 children with a mean (SD) age of 4.7 (±3) years, 47.9% [95%-CI 38%-57.9%] oropharyngeal airways were properly sized, while 23.4% [95%-CI 15.9%-33%] were undersized, and 28.7% [95%-CI 20.5%-38.7%] oversized. Tongue protrusion occurred in 59.1% [95%-CI 38.2%-77.2%] of undersized and 15.6% [95%-CI 7.6%-29.2%] of properly sized oropharyngeal airways. No oropharyngeal airway required replacement. Comparing probabilities for five landmark-distances, "maxillary incisors to the angle of the mandible" proved superior for proper sizing at 41.2% [95%-CI 32%-51.7%]. The best-fit formula was "22.43 + 17.54 × log(weight[kg])" with a probability of 61.7% [95%-CI 51.5%-70.9%].

CONCLUSION

Although the facial landmark-distance "maxillary incisors to the angle of the mandible" does not reliably predict oropharyngeal airway size, no clinical problems have been encountered. Since it can be considered the least inaccurate facial landmark-distance, it can serve as an approximation, but the efficacy of oropharyngeal airways should be evaluated clinically.

REGISTERED CLINICAL TRIAL

German Clinical Trials Register; DRKS00025918.

Tracheal Tube Misplacement after Emergency Intubation in Pediatric Trauma Patients: A Retrospective, Exploratory Study

Inadvertent tracheal tube misplacement and particularly endobronchial intubation are well-known complications of emergency endotracheal intubation (ETI) in pediatric trauma patients, which require repositioning of the tube to avoid impairment of gas exchange. The main aim of study was to identify the frequency of tube misplacement and associated factors of pediatric trauma patients who received ETI either by prehospital physician-staffed emergency medical service (EMS), or at emergency department (ED) admission to a single level-1 trauma center. Sixty-five patients (median age 14 years and median injury severity score 29) were included. Of these, 30 underwent helicopter EMS ETI, 29 ground EMS ETI, and 6 ED ETI. Seventeen cases (26%) of tracheal tube misplacement were recognized. After multivariable analysis, tracheal tube misplacement was independently negatively associated with body weight (OR 0.86; 95% CI, 0.76–0.99; p = 0.032) and helicopter EMS ETI (OR 0.20; 95% CI, 0.04–0.97; p = 0.036). Two of nineteen patients received tube thoracostomy due to endobronchial intubation. Mortality and length of stay were comparable in patients with misplaced tubes and correctly placed tubes. The results suggest that particularly small children require attention to avoid tracheal tube misplacement, which emphasizes the need for special training. Helicopter EMS physicians’ expertise might be beneficial in prehospital pediatric trauma patients requiring advanced airway management.

Ideal Depth of Endotracheal Intubation at the Vocal Cord Level in Pediatric Patients Considering Racial Differences in Tracheal Length

Numerous formulas that can predict endotracheal intubation depth at the corner of the mouth or the nasal wing of patients have been reported, even though the oral and nasal cavity anatomies differ among patients. Therefore, the purpose of this study was to derive a simple and reliable formula to predict the ideal endotracheal tube insertion depth at the vocal cord level in pediatric patients. The current study was conducted as a retrospective observational study, involving 425 and 335 cardiac pediatric patients in Germany and Japan, respectively, and aimed to determine a formula for predicting tracheal length and ideal depth of endotracheal intubation at the vocal cord level in pediatric patients. The distance between the vocal cords and the carina tracheae was defined as the tracheal length, and was measured on preoperative chest radiographs obtained in the supine position. The tracheal length in cardiac pediatric patients ranged from 6 to 10% of the body height in Germany and from 7 to 11% in Japan. This study revealed racial differences in the tracheal length, that is, in the ideal depth of endotracheal intubation at the vocal cord level. This study suggests that an adequate endotracheal intubation depth can be achieved by inserting endotracheal tubes at the vocal cord level with the minimum tracheal length of each racial group in pediatric patients, for example, 6% and 7% of the body height in Europeans and Asians, respectively. If the endotracheal tube inserted with this method appears to be shallow on chest radiographs, this does not represent an increased risk of accidental extubation, due to an excessively short intubation depth, because the minimum tracheal length for each racial group is considered. That is, it is not due to the endotracheal tube insertion length, but is likely due to the tracheal length of the patient, who has a relatively long tracheal length in the racial group.

Effect of head position changes on the depth of tracheal intubation in pediatric patients: A prospective, observational study

PURPOSE

The purpose of this study was to investigate the effect of changing head position on the endotracheal tube (ETT) depth and to assess the risk of inadvertent extubation and bronchial intubation in pediatric patients.

METHODS

Subjects aged 4-12 years old with orotracheal intubation undergoing elective surgeries were enrolled. After induction, the distances between "the ETT tip and the trachea carina" (T-C) were measured using a Disposcope flexible endoscope in head neutral position, 45° extension and flexion, 60° right and left rotation. The distance of the ETT tip movement relative to the neutral position (ΔT-C) was calculated after changing the head positions. The direction of the ETT tip displacement and the adverse events including endobronchial intubation, accidental tracheal extubation, hoarseness and sore throat were recorded.

RESULTS

The ETT tip moved toward the carina by 0.5 ± 0.4 cm (P < 0.001) when the head was flexed. After extending the head, the ETT tip moved toward the vocal cord by 0.9 ± 0.4 cm (P < 0.001). Right rotation resulted that the ETT tip moved toward the vocal cord direction by 0.6 ± 0.4 cm (P < 0.001). Moreover, there was no displacement with the head on left rotation (P = 0.126). Subjects with the reinforced ETT had less ETT displacement after changing head position than the taper guard ETT.

CONCLUSION

The changes of head position can influence the depth of the ETT especially in head extension. We recommend using the reinforced ETT to reduce the ETT displacement in pediatrics to avoid intubation complications.

CLINICAL TRIAL REGISTRATION

[www.ClinicalTrials.gov], identifier, [ChiCTR2100042648].

Exploring the Necessity of Routine Daily Chest X-rays for Mechanically Ventilated Patients in the Pediatric Intensive Care Unit: An Integrative Review

PROBLEM

In the PICU of a university teaching hospital, daily chest X-rays (CXR) are performed on all intubated and non-invasive ventilation-assisted patients, even when the patient is stable with no changes in clinical status. Inconsistent practice was identified with PICUs globally. This review aims to address the risk-benefit balance of clinical value, outcomes, cost, and radiation exposure when performing routine daily CXRs in the PICU.

ELIGIBILITY CRITERIA

CINAHL, Medline, and Embase (Ovid) were searched for relevant articles within the last ten years (2009 to 2019). Articles involving routine daily CXR on adult patients were included due to limited pediatric research.

SAMPLE

18 articles were included in this review which evaluated the necessity of routine daily CXR protocol in the ICU setting and the risks of radiation exposure (pediatric n = 5, adult n = 10, both n = 3).

RESULTS

When comparing the routine daily to on-demand CXR ordering protocols, there was no difference noted in clinical outcomes including mortality, complications, length of stay in hospital or ICU, and number of ventilator days. The on-demand CXR protocol decreased the number of CXRs per patient, which thereby decreased radiation exposure for patients, decreasing their risk of potential toxicity and malignancy.

CONCLUSION

Routine daily CXR protocols are no longer recommended due to lack of clinical value, similar outcomes, increased cost, and since it places patients at risk for undue radiation exposure.

IMPLICATIONS

Further studies should evaluate clinical and physical exam findings that would trigger ordering a CXR in order to optimize their diagnostic value in the pediatric setting.

Working with estimation-formulas to predict nasopharyngeal airway insertion depth in children: Looking at magnetic resonance images - A prospective observational study (WEND:LI-Study)

OBJECTIVE

To determine the accuracy of the recently proposed landmark-method 'nostril-to-tragus minus 10 mm' and compare with ERC-recommended distances for nasopharyngeal airway length sizing in children.

METHOD

We conducted a prospective observational study in sedated children < 12 years. Nasopharyngeal airways were inserted following 'nostril-to-tragus minus 10 mm'. Primary outcome was the rate of nasopharyngeal airway tips between soft palate and epiglottis on magnetic resonance imaging (MRI) indicated for medical reasons. An optimal placement was defined when the tip lied within 25-75% of the total soft palate-to-epiglottis distance. Between 0-100% of this distance, placement was still considered acceptable, below 0% too proximal or above 100% too distal. Secondary outcomes were the rate of adverse events, the qualitative positions of airway tips, and the comparison of ́nostril-to-tragus minus 10 mḿ with the ERC-recommended distances 'nostril-to-angle of the mandible' and 'nostril-to-tragus' with objective MRI measurements.

RESULTS

We analysed 92 patients with a mean age of 4.3 years. Nasopharyngeal airways were optimally placed in 37.0% (8.7% too proximal-77.2% acceptable-14.1% too distal). Three qualitative malpositions, but no airway-associated adverse event occurred. Objective measurements on MRI revealed the probability of 40.2% optimally placed nasopharyngeal airways (5.4%-67.4%-27.2%) for 'nostril-to-tragus minus 10 mm', 38.0% (17.4%-58.7%-23.9%) for 'nostril-to-mandible' and 13.0% (0%-28.3%-71.7%) for 'nostril-to-tragus', respectively.

CONCLUSION

No landmark-method predicted nasopharyngeal airway position reliably. 'Nostril-to-tragus minus 10 mm' seems the least inaccurate one and could be a valuable approximation until another estimation-formula proves more accurate. During insertion, careful clinical evaluation of airway patency is crucial.

REGISTERED CLINICAL TRIAL

German Clinical Trials Register; DRKS00021007.

[Ventilation in Pediatric Anesthesia]

About nine percent of all anesthesia procedures per year are performed in children. The risk for complications in pediatric anesthesia is higher in comparison with adults. There are significant differences in anatomy, physiology and pharmacology between pediatric and adult patients. Respiratory complications and circulations dysregulation occur more often in children. The most important consideration in the safe practice of pediatric anesthesia is to ensure a patent airway. Appropriate intraoperative management of newborns and infants needs a senior anesthetist with good knowledge and clinical experience including the management of possible complications.

Length of the Cricoid and Trachea in Children: Predicting Intubation Depth to Prevent Subglottic Stenosis

OBJECTIVE

Define the length of the subglottis and trachea in children to predict a safe intubation depth.

METHODS

Patients <18 years undergoing rigid bronchoscopy from 2013 to 2020 were included. The carina and inferior borders of the cricoid and true vocal folds were marked on a bronchoscope and distances were measured. Patient age, weight, height, and chest height were recorded. Four styles of cuffed pediatric endotracheal tubes (ETT) were measured and potential positions of each cuff and tip were calculated within each trachea using five depth of intubation scenarios. Multivariate linear regression was performed to identify predictors of subglottic and tracheal length.

RESULTS

Measurements were obtained from 210 children (141 male, 69 female), mean (SD) age 3.21 (3.66) years. Patient height was the best predictor of subglottic length (R² : 0.418): Length_sg (mm) = 0.058 * height (cm) + 2.8, and tracheal length (R² : 0.733): Length_t (mm) = 0.485 * height (cm) + 21.3. None of the depth of intubation scenarios maintained a cuff-free subglottis for all ETT styles investigated. A formula for depth of intubation: Length_di (mm) = 0.06 * height (cm) + 8.8 found that no ETT cuffs would be in the subglottis and all tips would be above the carina.

CONCLUSION

Current strategies for determining appropriate depth of intubation pose a high risk of subglottic ETT cuff placement. Placing the inferior border of the vocal cords 0.06 * height (cm) + 8.8 from the superior border of the inflated ETT cuff may prevent subglottic cuff placement and endobronchial intubation.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Clinical Use of Preformed Microcuff® Pediatric Endotracheal Tubes in Japan

Preformed cuffed oral endotracheal tubes are widely used to intubate children undergoing oral surgery. To evaluate the efficacy and safety of oral Ring-Adair-Elwyn (RAE) Microcuff® pediatric endotracheal tubes, we retrospectively investigated the endotracheal tube exchange rate and associated complications in Japanese children younger than 2 years of age undergoing cheiloplasty or palatoplasty. The exchange rate was 3.5%, and although unplanned extubations occurred in 2 patients, no severe complications were observed. Our results suggest that oral RAE Microcuff® tubes are effective and safe for intubating Japanese children younger than 2 years of age, with a low tube exchange rate and minor complications.

Point of care airway ultrasound to select tracheal tube and determine insertion depth in cleft repair surgery

We aimed to evaluate the efficacy of using airway ultrasonography to select the correct tracheal tube size and insertion depth in pediatric patients who underwent cleft repair surgery as a way to decrease airway complications and adverse events during perioperative periods. Fifty-one patients (age < 28 months) were consecutively divided into conventional (n = 28) and ultrasound (n = 23) groups. Tracheal tube size and insertion depth were determined using the age-based formula and auscultation in the conventional group, whereas using ultrasonographic measurement of subglottic diameter with auscultation and lung ultrasonography in the ultrasound group. We evaluated the initially selected tube size, insertion depth, ventilatory indices, and the incidence of airway complications and adverse events. Tube insertion depth (median [interquartile range]) was significantly greater in the ultrasound group than in the conventional group (13.5 cm [12.5-14.0] vs 13.0 cm [11.8-13.0], P = 0.045). The number of complications and adverse events was significantly higher in the conventional group than in the ultrasound group (32.1% vs 4.3%, P = 0.013). Airway ultrasound application could reduce airway-related complications and adverse events by determining the appropriate tracheal tube size and insertion depth.

Simulated dimensional compatibility of uncuffed and cuffed tracheal tubes for selective endobronchial intubation in children

BACKGROUND

Cuffed tracheal tubes have recently been recommended for selective endobronchial intubation to establish single-lung ventilation even in smaller children. This implies that, compared with uncuffed tracheal tubes, the cuffed tracheal tubes selected will be smaller and therefore have a shorter length. We hypothesized that cuffed tracheal tubes might be of insufficient length for selective endobronchial intubation if the tube cuff were fully immersed in the left or right mainstem bronchus.

METHODS

The distance from the proximal end of the tracheal tube to the upper border of the cuff in cuffed tracheal tubes and to the upper margin of the Murphy eye in uncuffed tracheal tubes, respectively, was assessed in sizes 3.0-7.0 mm internal diameter. The raw data sets of two previously performed studies obtained from 337 children aged from birth to 16 years, including the distances "teeth to tracheal tube tip" and "tracheal tube tip to carina," were used to calculate age-, weight-, and height-related data for the distance from "teeth to carina." Tracheal tube dimensions were compared with age-related distances from "teeth to carina," applying published recommendations for the selection of uncuffed and cuffed tracheal tubes for selective endobronchial intubation in children.

RESULTS

The differences between the length of the age-related tracheal tube and the tracheal tube insertion length required to guarantee full insertion of the tracheal tube cuff or the Murphy eye within the mainstem bronchus ranged from -3.5 to 52.6 mm in cuffed tracheal tubes and from 42.3 to 83.3 mm in uncuffed tracheal tubes.

CONCLUSIONS

For many age groups of patients requiring selective endobronchial intubation, the lengths of cuffed tracheal tubes, in contrast to those of uncuffed tracheal tubes, were revealed to be critically short for safe taping outside the oral cavity with the cuff placed completely within the right or left mainstem bronchus.

Comparison of tracheoscopy and portable chest X-Ray in the evaluation of infant tracheostomy tube position

OBJECTIVE

To compare tracheoscopy and chest radiograph measurements of tracheostomy tube position in infants.

STUDY DESIGN

Retrospective chart review.

SETTING

Otolaryngology Department at Penn State Milton S. Hershey Medical Center.

SUBJECTS AND METHODS

All cases of pediatric patients who underwent tracheotomy at less than 1 year of age from 2014 to 2019 were reviewed. Patients were included if they had both intraoperative measurement of tracheostomy tube position relative to the carina by tracheoscopy and postoperative chest radiograph. Documented intraoperative findings were compared to measurements made on chest radiograph by an attending radiologist blinded to the intraoperative measurements.

RESULTS

The study included 66 patients; 30 patients (14:16, M:F) had available data. The mean distance from the distal tracheostomy tube to the carina measured by tracheoscopy was 8.88 mm (range, 3.5-20 mm) and measured radiographically was 11.71 mm (range, 2.4-23.3 mm). The mean difference between the measurements was 2.82 mm (p-value = 0.016). Ninety percent (n = 27) of patients had measurements that differed by greater than 2 mm; 53% (n = 16) had measurements that differed by 5 mm and 1% (n = 3) had measurements differing by greater than 10 mm.

CONCLUSION

In the infant population, significant discrepancy was found between direct tracheoscopy and chest radiograph measurements of the tracheostomy tube position. Measurements obtained by chest radiographs tend to overestimate the relative distance of the distal tracheostomy tube to the carina as compared to that of tracheoscopy. Clinical decisions regarding changes to tracheostomy tube sizes should mostly rely on tracheoscopy performed with the patient supine.

Real-Time Optical Monitoring of Endotracheal Tube Displacement

Proper ventilation of a patient with an endotracheal tube (ETT) requires proper placement of the ETT. We present a sensitive, noninvasive, operator-free, and cost-effective optical sensor, called Opt-ETT, for the real-time assessment of ETT placement and alerting of the clinical care team should the ETT become displaced. The Opt-ETT uses a side-firing optical fiber, a near-infrared light-emitting diode, two photodetectors with an integrated amplifier, an Arduino board, and a computer loaded with a custom LabVIEW program to monitor the position of the endotracheal tube inside the windpipe. The Opt-ETT generates a visual and audible warning if the tube moves over a distance set by the operator. Displacement prediction is made using a second-order polynomial fit to the voltages measured from each detector. The system is tested on ex vivo porcine tissues, and the accuracy is determined to be better than 1.0 mm. In vivo experiments with a pig are conducted to test the performance and usability of the system.

Impact of changes in head position during head and neck surgery on the depth of tracheal tube intubation in anesthetized children

Background

The classic formula has been used to estimate the depth of tracheal tube intubation in children for decades. However, it is unclear whether this formula is applicable when the head and neck position changes intraoperatively.

Methods

We prospectively reviewed the data of 172 well-developed children aged 2–12 years (64.0% boys) who underwent head and neck surgery under general anesthesia. The distances from the tracheal carina to the endotracheal tube tip (CT), from the superior margin of the endotracheal tube tip to the vocal cord posterior commissure (CV), and from the tracheal carina to the posterior vocal commissure (TV) were measured in the sniffing position (maximum), neutral head, and maximal head flexion positions.

Results

Average CT and CV in the neutral head position were 4.33 cm and 10.4 cm, respectively. They increased to 5.43 cm and 11.3 cm, respectively, in the sniffing position, and to 3.39 cm and 9.59 cm, respectively, in the maximal flexion position (all P-values < 0.001). TV remained unchanged and was only dependent on age. After stratifying patients by age, similar results were observed with other distances. CT and CV increased by 1.099 cm and 0.909 cm, respectively, when head position changed from neutral head to sniffing position, and decreased by 0.947 cm and 0.838 cm, respectively, when head position changed from neutral head to maximal flexion.

Conclusion

Change in head position can influence the depth of tracheal tube intubation. Therefore, the estimated depth should be corrected according to the surgical head position.

Use of the Microcuff® During General Anesthesia for Patients With Scoliosis

Scoliosis may often be associated with a variety of cardiovascular and respiratory conditions or diseases, and depending on the severity of the spinal deformity, it may also complicate anesthetic management because of the difficulty of neck extension and tracheal deformity. Therefore, patients with scoliosis may require careful perioperative anesthetic considerations. A 14-year-old girl was scheduled to undergo extractions and restorative treatment for dental caries under general anesthesia. Her medical history was significant for intellectual disability and autism as well as previously undiagnosed scoliosis. After fixation of a 6.0 Portex^® endotracheal tube (ETT), percutaneous oxygen saturation (SpO₂) decreased to 93%, peak airway pressures increased, and unilateral lung ventilation was noted. Inadvertent mainstem bronchial intubation was immediately suspected, prompting removal of the Portex ETT and reintubation with a shorter 6.0 Microcuff^® ETT. The dental treatment was completed successfully without further incident. Assessment of the ETTs used intraoperatively led to the determination that the distance from the glottis to the carina was considerably shorter than normal for this patient. It was speculated that the Microcuff ETT may be optimal for anesthetic management of scoliosis patients because of its shorter lengths compared with other style ETTs, which may reduce the risk of bronchial intubation in such cases.

Endotracheal Tube Migration Associated With Extension During Tracheotomy

Tracheotomy is occasionally performed to prevent postoperative airway obstruction especially for invasive surgical procedures involving head and neck cancer. When performed under general anesthesia, attention must be paid to avoid rupture of the tracheal tube cuff during the incision into the trachea. In this study, changes in the position of the endotracheal tube tip during extension of the head and neck for a tracheotomy were investigated. Twelve patients underwent placement of a tracheotomy during surgical procedures for oral cancer. After nasal intubation, the distance between the tube tip and the carina was measuring using a fiberoptic scope with the patient's head placed at an angle of 110°. Patients were repositioned for tracheotomy by placing a pillow under the shoulders and extending the head and neck at an angle of 140°. The distance measurements were subsequently repeated. The difference between the first and second measurements was calculated and analyzed statistically using a paired t test. On average the patients were 69.5 ± 9.0 years in age. The distance between the tube tip and the carina at an angle of 140° (3.6 ± 1.1 cm) was significantly longer than that at an angle of 110° (1.7 ± 1.0 cm) (p < 0.001). The migration in the positioning of the endotracheal tube tip was 1.9 ± 0.7 cm (range: 0.7-3.7 cm) upon extension. In 3 cases, the tube cuff was ruptured during incision of the trachea. The endotracheal tube tip may migrate in the cephalad direction approximately 2 cm as a result of the extension of the patient's head and neck during a tracheotomy. Therefore, consideration should be given to advancing the endotracheal tube tip towards the caudal side and to confirming the position of the tube and cuff during a tracheotomy.

The Occurrence and Risk Factors of Inappropriately Deep Tip Position of Microcuff Pediatric Endotracheal Tube During PICU Stay: A Retrospective Cohort Pilot Study

OBJECTIVES

Cuffed endotracheal tubes are being used increasingly for pediatric patients on mechanical ventilation. Appropriate placement of the tube tip for Microcuff (Kimberley-Clark, Roswell, GA) pediatric endotracheal tube is guided by the intubation depth mark on the device. However, inappropriately deep tip position is sometimes observed during PICU stay. The purpose of this study was to assess the occurrence and risk factors of inappropriately deep tip position of Microcuff pediatric endotracheal tube during PICU stay.

DESIGN

A retrospective cohort study.

SETTING

The PICU at the National Center for Child Health and Development, one of the largest tertiary pediatric hospitals in Japan.

PATIENTS

All patients on mechanical ventilation with Microcuff pediatric endotracheal tube admitted between February 1, 2015, and July 31, 2016, were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the occurrence of inappropriately deep tip position, defined as a position of the tube tip less than 5 mm above the carina on a chest radiograph. There were 179 cases (157 patients) requiring mechanical ventilation with Microcuff pediatric endotracheal tube during the study period. An inappropriately deep tip position was found in 42 cases (23.5%), including bronchial intubation in 13 cases (7.3%). In multivariate analysis, height in cm (odds ratio, 0.93; p < 0.001), history of abdominal disease or previous abdominal surgery (odds ratio, 4.38; p = 0.004), and oversized endotracheal tube (odds ratio, 2.93; p = 0.042) were found to be independent risk factors.

CONCLUSIONS

The occurrence of inappropriately deep tip position of Microcuff pediatric endotracheal tube during PICU stay was 23.5%. The possibility of an inappropriately deep tip position should be considered whenever patients with the above risk factors, a history of abdominal disease or previous abdominal surgery, and small children are treated or when oversized endotracheal tubes are used.

Pediatric airway dimensions-A summary and presentation of existing data

BACKGROUND

Age-related pediatric airway dimension reference values for cricoid, tracheal, and bronchial diameters as well as tracheal and bronchial lengths are essential for distinguishing normal from pathological airway findings and for manufacturing and selecting appropriately sized airway equipment.

AIM

The aim of this work was to summarize and present existing pediatric airway dimension data for the larynx, trachea, and main stem bronchi from fetus to adolescence.

METHODS

A systematic literature search was carried out using PubMed, Scopus, Embase, and Google Scholar. Publications containing original data on pediatric airway dimensions as mean or median in tabular form and spanning narrow age groups of 1 or 2 years were included in our study. Original data such as diameters, lengths, and cross-sectional areas of trachea, cricoid, left and right main bronchi in fetuses and children were collected and presented as figures.

RESULTS

Pediatric airway dimension data were gathered and compiled from 15 studies fulfilling the inclusion criteria. Data were obtained from different measurement methods such as autopsy, chest X-ray, computed tomography, magnetic resonance imaging, rigid and flexible bronchoscopy as well as ultrasound examinations. There was considerable variation among age-related data due to biologic heterogeneity, different presentation of data, different definitions, and various measurement techniques.

CONCLUSION

This investigation revealed heterogeneous data on pediatric airway dimensions, making it impossible to compile them into standard reference values for airway dimensions. New studies with structured and standardized measurements and data presentation in large populations of children are required to provide more valid pediatric airway dimension data.

Pediatric tracheal dimensions on computed tomography and its correlation with tracheostomy tube sizes

OBJECTIVE

Age-based formulas for selecting the appropriate size of tracheostomy tubes in children are based on data on tracheal dimensions. This study aims to measure the tracheal dimensions of Indian children by computerized tomography (CT) and to compare this with the dimensions of age-appropriate tracheostomy tubes.

METHODS

CT scans of children aged less than 16 years that were taken for indications other than respiratory distress were included. Tracheal diameters at the tracheostomy point and tracheal length from the tracheostomy point to the carina were calculated from the scans. These dimensions were correlated with age, weight, and height. The measurement on the CT scan was used to predict the appropriate size of tracheostomy tube, which was compared with the tracheostomy tube sizes.

RESULTS

Two hundred and fourteen CT scans of children aged below 16 years were included in the study. On multiple logistic regression analysis, tracheal diameter correlated well with age and weight (P = 0.04 and 0.001, respectively), whereas tracheal length correlated well with age and height of the child (P = 0.03 and 0 < 0.001, respectively). On comparison with dimensions of the tracheostomy tube, tracheal diameter correlated well, and the length was found to be longer than needed to prevent endobronchial intubation. The regression value was used to predict the size of an ideal tracheostomy tube.

CONCLUSION

Tracheal diameter of Indian children correlates well with the outer diameter of age-appropriate tracheostomy tubes, but the length of these tubes is longer than the ideal length. This would necessitate a change in the design of these tubes.

LEVEL OF EVIDENCE

2b Laryngoscope, 130:1316-1321, 2020.

Changes in nasotracheal tube depth in response to head and neck movement in children

BACKGROUND

A tracheal tube is often inserted via the nasal cavity for dental surgery. The position of the tube tip is important, given that the head position sometimes changes during surgery. Head movement induces changes in the length of the trachea (t-length) and/or the distance between the nare and the vocal cords (n-v-distance). In this study, we investigated the changes in t-length and n-v-distance in children undergoing nasotracheal intubation.

METHODS

Eighty patients aged 2-8 year undergoing dental surgery were enrolled. After nasotracheal intubation with an uncuffed nasotracheal tube (4.5-6.0 mm), the tube was fixed at the patient's nares. The distance between the tube tip and the first carina was measured using a fibrescope with the angle between the Frankfort plane and horizontal plane set at 110°. The location of the tube in relation to the vocal cords was then checked. These measurements were repeated at angles of 80° (flexion) and 130° (extension). The t-length and n-v-distance were then calculated using these measurements.

RESULTS

On flexion, the t-length shortened significantly from 87.5 ± 10.4 mm to 82.9 ± 10.7 mm (P = 0.017) and the n-v-distance decreased from 128.1 ± 10.7 mm to 125.6 ± 10.4 mm (P = 0.294). On extension, the t-length increased significantly from 87.5 ± 10.4 mm to 92.7 ± 10.1 mm (P = 0.007) and the n-v-distance increased from 128.1 ± 10.7 mm to 129.4 ± 10.7 mm (P = 0.729). The change in t-length was significantly greater than that in the n-v-distance.

CONCLUSION

A change in the position of the tracheal tube tip in the trachea depends mainly on changes in t-length during paediatric dental surgery.

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.

Airway Management for a Pediatric Patient With a Tracheal Bronchus

Tracheal bronchus is an ectopic bronchus almost arising from the right side of the tracheal wall above the carina. The incidence of a tracheal bronchus is reported as 0.1 to 3%. We experienced a patient with tracheal bronchus that was incidentally found at induction of anesthesia. Endotracheal intubation in a patient with tracheal bronchus might cause obstruction of the tracheal bronchus, although in this case, ventilation was not impaired.

New decision formulas for predicting endotracheal tube depth in children: analysis of neck CT images

INTRODUCTION

The purpose of this study was to construct a prediction model for endotracheal tube depth using neck CT images.

METHODS

A retrospective image review was conducted that included patients who had undergone neck CT. Using sagittal neck CT images, we calculated the length between upper incisor and mid-trachea and then derived the model via regression analysis. The model was validated externally using chest radiographs of patients who had undergone endotracheal intubation. We compared performance of our model with that of other methods (Broselow tape and APLS formula) via Bland-Altman analysis and the percentage of estimations within 10% of the measured values.

RESULTS

A total of 1111 children were included in this study. The tube depth obtained from CT images was linearly related to body weight (tube depth (cm)=5.5+0.5×body wt (kg)) in children younger than 1 year and to height (tube depth (cm)=3+0.1×height (cm)) in children older than 1 year. External validation demonstrated that our new model showed better agreement with the desired tube depth than Broselow tape and APLS formula. The mean differences in children younger than 1 year were 0.61 cm and -1.24 cm for our formula and Broselow tape, respectively. The mean differences in children older than 1 year were -0.43 cm, -1.98 and -1.64 cm for our formula, Broselow tape and APLS formula, respectively. The percentages of estimates within 10% of the measured values were 52.7% and 35.8% for our formula and Broselow tape in children younger than 1 year, respectively, and 54.3%, 33.8% and 37.2% for our formula, Broselow tape and APLS formula in children older than 1 year, respectively (P<0.01).

CONCLUSION

Our new formula is useful and more accurate than the currently available methods.

Pulmonary atelectasis in newborns with clinically treatable diseases who are on mechanical ventilation: clinical and radiological aspects

Objective

To analyze the radiological aspects of pulmonary atelectasis in newborns on mechanical ventilation and treated in an intensive care unit, associating the characteristics of atelectasis with the positioning of the head and endotracheal tube seen on the chest X-ray, as well as with the clinical variables.

Materials and Methods

This was a retrospective cross-sectional study of 60 newborns treated between 1985 and 2015. Data were collected from medical records and radiology reports. To identify associations between variables, we used Fisher's exact test. The level of significance was set at p < 0.05.

Results

The clinical characteristics associated with improper positioning of the endotracheal tube were prematurity and a birth weight of less than 1000 g. Among the newborns evaluated, the most common comorbidity was hyaline membrane disease. Atelectasis was seen most frequently in the right upper lobe, although cases of total atelectasis were more common in the left lung. Malpositioning of the head showed a trend toward an association with atelectasis in the left upper lobe.

Conclusion

Pulmonary atelectasis is a common complication in newborns on mechanical ventilation. Radiological evaluation of the endotracheal tube placement provides relevant information for the early correction of this condition.

A smartphone application to determine body length for body weight estimation in children: a prospective clinical trial

The aim of this study was to test the feasibility and accuracy of a smartphone application to measure the body length of children using the integrated camera and to evaluate the subsequent weight estimates. A prospective clinical trial of children aged 0-<13 years admitted to the emergency department of the University Children's Hospital Zurich. The primary outcome was to validate the length measurement by the smartphone application «Optisizer». The secondary outcome was to correlate the virtually calculated ordinal categories based on the length measured by the app to the categories based on the real length. The third and independent outcome was the comparison of the different weight estimations by physicians, nurses, parents and the app. For all 627 children, the Bland Altman analysis showed a bias of -0.1% (95% CI -0.3-0.2%) comparing real length and length measured by the app. Ordinal categories of real length were in excellent agreement with categories virtually calculated based upon app length (kappa = 0.83, 95% CI 0.79-0.86). Children's real weight was underestimated by physicians (-3.3, 95% CI -4.4 to -2.2%, p < 0.001), nurses (-2.6, 95% CI -3.8 to -1.5%, p < 0.001) and parents (-1.3, 95% CI -1.9 to -0.6%, p < 0.001) but overestimated by categories based upon app length (1.6, 95% CI 0.3-2.8%, p = 0.02) and categories based upon real length (2.3, 95% CI 1.1-3.5%, p < 0.001). Absolute weight differences were lowest, if estimated by the parents (5.4, 95% CI 4.9-5.9%, p < 0.001). This study showed the accuracy of length measurement of children by a smartphone application: body length determined by the smartphone application is in good agreement with the real patient length. Ordinal length categories derived from app-measured length are in excellent agreement with the ordinal length categories based upon the real patient length. The body weight estimations based upon length corresponded to known data and limitations. Precision of body weight estimations by paediatric physicians and nurses were comparable and not different to length based estimations. In this non-emergency setting, parental weight estimation was significantly better than all other means of estimation (paediatric physicians and nurses, length based estimations) in terms of precision and absolute difference.

The Tracheal Accordion and the Position of the Endotracheal Tube

The purpose of this review is to, first, determine the static factors that affect the length of the human trachea across different populations and, second, to investigate whether or not there are dynamic factors that cause the length of the human trachea to vary within the same individual. We also investigated whether these changes in tracheal length within the same individual are significant enough to increase the risk of endobronchial intubation or accidental extubation. A PubMed/MEDLINE and a Web of Science database English-language literature search was conducted in May 2016 with relevant keywords and MeSH terms when available. We found that gender, extremes of age, patient height, postsurgical changes and co-existing disease are static patient factors that affect the length of the human trachea. Dynamic clinical changes that occur under anaesthesia, including Trendelenburg position, head and neck flexion and extension, paralysis of the diaphragm and pneumoperitoneum, cause the trachea to act as an accordion, decreasing and increasing its length. The length of the human trachea in both awake and anaesthetised and paralysed patients is a critical consideration in preventing both endobronchial intubation and tracheal extubation. It is clear from the literature that tracheal length varies widely across populations and, additionally, with the dynamic clinical changes that occur under anaesthesia, the trachea acts as an accordion decreasing and increasing its length within the same individual. Knowledge of the magnitude of the change in tracheal dimensions in response to these factors is an important clinical consideration.

Automatic Detection of Endotracheal Intubation During the Anesthesia Procedure

This paper is concerned with the mathematical modeling and detection of endotracheal (ET) intubation in children under general anesthesia during surgery. In major pediatric surgeries, the airway is often secured with an endotracheal tube (ETT) followed by initiation of mechanical ventilation. Clinicians utilize auscultation of breath sounds and capnography to verify correct ETT placement. However, anesthesia providers often delay timely charting of ET intubation. This latency in event documentation results in decreased efficacy of clinical decision support systems. In order to target this problem, we collected real inpatient data and designed an algorithm to accurately detect the intubation time within the clinically valid range; the results show that we are able to achieve high accuracy in more than 96% of the cases. Automatic detection of ET intubation time would thus enhance better real-time data capture to support future improvement in clinical decision support systems.

Patient-specific depth of endotracheal intubation-from anthropometry to the Touch and Read Method

Objective:

Knowledge of accurate airway length (AL) enables safer placement of the endotracheal tube (ETT) in the trachea. Our objective was to check the safety of a new formula (Touch and Read method) to determine ETT depth.

Methods:

AL was measured in 176 patients. Patients were divided into a normal group (AL >25 cm in men, >23 cm in women) and a risk group (AL ≤25 cm in men, ≤23cm in women). A control test (Conventional method) was performed in which the ETT was secured at a depth of 23 cm from the central incisor in men and 21 cm in women. In the experimental test (Touch and Read method), the ETT was secured at a depth equal to the distance from the angle of the mouth to the epiglottis tip plus 12.5 cm in men and 11.5 cm in women. The mean distance from the tube tip to the carina and that from the vocal cords to tube cuff were compared between the control and experimental tests in each group.

Results:

The two distances were similar between control and experimental tests in the normal group, but differed in the risk group (Women: mean distance from tube tip to carina, 1.2 cm and from vocal cords to cuff, 2.7 cm [control test]; 1.9 and 2.0 cm, respectively [experimental test]. Men: 0.7 and 3.5 cm, respectively [control test]; 2.0 and 2.3 cm, respectively [experimental test]).

Conclusion:

Touch and Read method enables safer placement of the ETT in the trachea than the conventional method in the risk group.

Endotracheal tube displacement during head and neck movements. Observational clinical trial

STUDY OBJECTIVE

Measure the displacements of endotracheal tube (ETT) tip displacement during head and neck movements.

DESIGN

Observational study.

SETTING

Ear-nose-throat (ENT) and neurosurgery operating room.

PATIENTS

We performed a maximal head-neck movement trial on 50 adult patients, American Society of Anaesthesiologists 1 or 2. Patients with body mass index >35 kg · m(-2), height <150 cm, airway malformations, pulmonary diseases, difficulties in neck flexion or extension, previous ENT surgery or radiotherapy, gastroesophageal reflux, or dental instability were excluded from the study.

INTERVENTIONS

ENT and neurosurgery.

MEASUREMENTS

We measured the change in distance between the ETT tip and the carina, using a fiberscope through the ETT.

RESULTS

After intubation, a wide disparity of tube tip distance to the carina in the neutral position was noted with a median of 5.0 (3.5-7.0) cm. Cephalad tube movement was documented following maximal head and neck extension in 34 (68%) patients and right head rotation in 25 patients (50%). Caudal tube displacement was due to maximal head and neck flexion in 38 patients (76%) and left head rotation in 25 patients (50%). Selective right main bronchus intubation was noted in 2 (4%) patients after maximal head extension.

CONCLUSION

Maximal head and neck movements led to unpredictable tube displacements. Proper reassessment of tube positioning after head and neck movement of intubated patients is therefore mandatory.

Ease and difficulty of pre-hospital airway management in 425 paediatric patients treated by a helicopter emergency medical service: a retrospective analysis

Background

Pre-hospital paediatric airway management is complex. A variety of pitfalls need prompt response to establish and maintain adequate ventilation and oxygenation. Anatomical disparity render laryngoscopy different compared to the adult. The correct choice of endotracheal tube size and depth of insertion is not trivial and often challenged due to the initially unknown age of child.

Methods

Data from 425 paediatric patients (<17 years of age) with any airway manipulation treated by a Swiss Air-Ambulance crew between June 2010 and December 2013 were retrospectively analysed. Endpoints were: 1) Endotracheal intubation success rate and incidence of difficult airway management in primary missions. 2) Correlation of endotracheal tube size and depth of insertion with patient’s age in all (primary and secondary) missions.

Results

In primary missions, the first laryngoscopy-guided endotracheal intubation attempt was successful in 95.3% of cases, with an overall success rate of 98.6%. Difficult airway management was reported in 10 (4.7%) patients. Endotracheal tube size was frequently chosen inadequately large (overall 50 of 343 patients: 14.6%), especially and statistically significant in the age group below 1 year (19 of 33 patients; p < 0.001). Tubes were frequently and distinctively more deeply inserted (38.9%) than recommended by current formulae.

Conclusion

Difficult airway management, including cannot intubate and cannot ventilate situations during pre-hospital paediatric emergency treatment was rare. In contrast, the success rate of endotracheal intubation at the first attempt was very high. High numbers of inadequate endotracheal tube size and deep placement according to patient age require further analysis. Practical algorithms need to be found to prevent potentially harmful treatment.

Agreement between lower esophageal and nasopharyngeal temperatures in children ventilated with an endotracheal tube with leak

BACKGROUND

A temperature probe placed in the lower third of the esophagus accurately reflects core temperature in anesthetized children. Temperature probes are commonly placed in the nasopharynx in children, but when utilizing an uncuffed endotracheal tube (ETT) with a softly audible leak, ventilated gases from the trachea can escape upwards toward the nasopharynx, thereby potentially causing a cooling effect in the nasopharynx.

OBJECTIVES

We sought to establish if nasopharyngeal and lower esophageal temperatures are in agreement in children undergoing general anesthesia, both in scenarios of ventilation with a cuffed ETT that has minimal or no leak (cuff up), as well as an ETT with leak (cuff down).

METHODS

A prospective, crossover agreement study was performed on anesthetized children. Children were intubated with a MicroCuff(®) ETT and had temperature probes inserted into both the nasopharynx and lower esophagus. Under standardized ventilator and gas flow settings, temperatures were recorded with the ETT cuff inflated, and with the cuff deflated. Bland-Altman plots were utilized to assess agreement of temperatures.

RESULTS

Fifty patients successfully completed this study. The mean difference between esophageal and nasopharyngeal temperature was found to be -0.03°C in the presence of minimal or no leak around the ETT (cuff up), with 95% limits of agreement (LOA) of -0.22 to 0.15°C. The mean difference between esophageal and nasopharyngeal temperature was found to be 0.1°C when a larger leak existed around the ETT (cuff down), with LOA of -0.31 to 0.51°C.

CONCLUSIONS

Nasopharyngeal temperature accurately reflects lower esophageal temperature when there is minimal or no ETT leak. When a larger ETT leak is present, nasopharyngeal temperature is on average 0.1°C cooler than lower esophageal temperature. As the nasopharyngeal temperature probe site confers the advantage of simplicity of accurate placement compared to its esophageal counterpart, our findings support the use of nasopharyngeal temperature probes in children ventilated with both cuffed and uncuffed ETTs.

Accuracy of a Chest X-Ray-Based Method for Predicting the Depth of Insertion of Endotracheal Tubes in Pediatric Patients Undergoing Cardiac Surgery

OBJECTIVES

The incidence of endotracheal tube (ETT) malposition in children with various described methods is 15% to 30%. Chest x-ray (CXR) is the gold standard for confirming appropriate ETT position. The aim of this study was to measure the accuracy of a preoperative CXR-based method in determining depth of insertion of ETTs and to compare it with methods based on the intubation depth mark or formulae (age, height, and ETT internal diameter) in children undergoing cardiac surgery.

DESIGN

Prospective observational study.

SETTING

University-affiliated tertiary care hospital.

PARTICIPANTS

Sixty-six consecutive children scheduled for elective pediatric cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The distance from carina to mid-trachea was measured for each child preoperatively on the CXR displayed as a computed radiography image in a picture archival and communications system computer. Following intubation, ETTs deliberately were pushed endobronchially and then pulled back to the carina; they were further withdrawn by the previously measured carina to mid-tracheal distance and secured. CXRs postoperatively were repeated to confirm ETT position. The ETT position was measured with other methods using the picture archival and communications system ruler on the postoperative CXR and compared with the CXR method. The proportion of appropriate ETT position with the CXR method was 98.5% (p≤0.001 v other methods). In children younger than 3 years, the appropriate proportion was 97.4%.

CONCLUSION

The appropriate positioning of ETTs in the trachea by the CXR method is superior to other methods.

Middle finger length-based tracheal intubation depth improves the rate of appropriate tube placement in children

BACKGROUND

It is challenging for anesthetists to determine the optimal tracheal intubation depth in children. We hypothesize that a measure three times the length of the middle finger can be used for predicting tracheal tube depth in children.

METHODS

Eighty-six children (4-14 years of age) were included in this study. After the children were anesthetized, a fiberoptic bronchoscope (FOB) was inserted into the trachea, the lengths from the upper incisor teeth to carina and vocal cords were measured, and a suitably sized cuffed tracheal tube was inserted into the trachea. Age-based and middle finger length-based formulas were used to determine the tracheal intubation depth.

RESULTS

All 86 children enrolled were included in this study. Compared with the age-based intubation, the rate of appropriate tube placement was higher for middle finger length-based intubation (88.37% vs 66.28%, P = 0.001). The proximal intubation rate was lower in middle finger length-based intubation (4.65% vs 32.56%, P < 0.001). There was only weak evidence for a difference in the distal intubation rate between the two methods (6.97% vs 1.16%, P = 0.054). The correlation coefficient between middle finger length and optimal tracheal tube depth was larger than that between age and optimal tracheal tube depth (0.883 vs 0.845).

CONCLUSIONS

Our data indicate that the appropriate tube placement rate can be improved by using three times the middle finger length as the tracheal intubation depth in children.

Nares-to-carina distance in children: does a 'modified Morgan formula' give useful guidance during nasal intubation?

BACKGROUND

Knowledge of the normal nares-to-carina (NC) distance might prevent accidental bronchial intubation and be helpful when designing preformed endotracheal tubes (ETT).

OBJECTIVE

The aim was to measure NC distance and to examine whether a height/length-based 'modified Morgan formula' would give useful guidance for nasotracheal ETT depth positioning.

METHODS

Two groups were studied. A younger group consisted of nasally intubated postoperative patients. In these, NC distance was obtained as the sum of ETT length and the distance from the ETT tip to the carina, as measured from an anteroposterior chest X-ray. An older group consisted of children who had undergone computerized tomography (CT) examination including head, neck, and chest. In these, NC was measured directly from the CT image. The modified Morgan formula was derived from the NC vs height/length relationship.

RESULTS

Nares-to-carina distance was best predicted by a linear equation based on patient height. The equation in the younger group (1 day-8 years, n = 57) was: NC (cm) = 0.14 × height + 5.8, R(2) = 0.90, and in the older group (2.1-20 years, n = 45): NC (cm) = 0.15 × height + 3.4, R(2) = 0.93. The equation for the groups combined (n = 102) was: NC (cm) = 0.14 × height + 6.2, R(2) = 0.97. Based on the latter equation, a modified Morgan formula was identified as: ETT position at nares in cm = 0.12 × height + 5. If the ETT had been placed as calculated by this formula, the ETT tip would have been at 85 + 5% (mean ± sd) of NC distance, and the ETT tip-to-carina distance would have been 3.1 ± 1.1 cm (range 0-6.6). Bronchial intubation would not have occurred in any child, but a comparison to tracheal length measurements indicates that ETT tip position could be too proximal in some children.

CONCLUSION

The study confirms previous reports: NC distance can be well predicted from height/length. A modified Morgan formula might decrease the risk for accidental endobronchial intubation in infants and children, but ETT position need to be confirmed by auscultation or other verification.

Are preformed endotracheal tubes appropriately designed for pediatric patients?

BACKGROUND

The aim of the study was to examine different brands of preformed oral and nasal endotracheal tubes (ETT) and to assess whether the bend placement gave acceptable guidance for ETT depth positioning in children.

METHODS

The distance from the vertex of the bend to the tip (bend-to-tip distance) of seven brands of preformed oral and nasal ETTs were measured. Front teeth-to-carina (FTC) and nares-to-carina (NC) distance data from orally (0-19 years) and nasally (0-8 years) intubated children were used to assess the risk of endobronchial intubation if a preformed ETT had been placed with its bend at the front teeth or nares.

RESULTS

While the bend-to-tip distance of a cuffed oral preformed ETT only differed by 0-1 cm from a same size ETT from another brand, uncuffed oral ETTs differed by 0-4 cm. The bend-to-tip distance of cuffed and uncuffed ETTs of the same brand and size differed by 0-3 cm. Had preformed cuffed oral ETTs been placed with their bends at the front teeth in children of the FTC reference group, endobronchial intubation would have occurred in 0-27% of the patients, depending on the size and brand of the used ETT. In contrast to oral ETTs, the bend-to-tip distance of cuffed nasal ETTs differed more (0-5.5 cm) between brands, and uncuffed nasal ETTs less (0-3 cm). Also, the bend-to-tip distance of a cuffed nasal ETT was consistently greater (2-9 cm) than that of a same brand and size nasal uncuffed ETT. Had a preformed cuffed nasal ETT been placed with its bend at the nares in the NC reference group, 50-100% of the patients would have been endobronchially intubated.

CONCLUSION

The bend-to-tip distance of preformed ETTs varies between brands, especially for nasal tubes. Some preformed tubes are not well suited for routine use in children. There is a high risk for accidental endobronchial intubation if a cuffed preformed ETT is positioned with its bend at the front teeth or nares in a young child. ETT tube tip position needs to be carefully controlled when a preformed ETT is used in a child.

Correlation between changes in thyromental distance and distance of migration of oral Ring-Adair-Elwyn tubes during neck extension with a shoulder positioner in patients undergoing neck procedures

Objectives

To measure the migration of oral Ring-Adair-Elwyn (RAE) preformed tracheal tubes during neck extension compared with the neutral neck position, and to assess the correlation between changes in the thyromental distance (TMD) during changes in neck position and tracheal tube migration.

Methods

This prospective observational study enrolled adult patients undergoing elective neck or thyroid procedures below the mandible. Using fibreoptic bronchoscopy, distances from the RAE tube adapter to the carina and to the tube tip were measured in the neutral position and after neck extension with a 10 cm D-shaped gel shoulder positioner. The change in distance of the RAE tube tip migration was compared with the change in TMD in each patient.

Results

This study enrolled 106 patients. During neck extension with a 10-cm shoulder positioner, RAE tubes cranially migrated 2.7 cm from the neutral position, but RAE tube migration was not correlated with the change in external TMD.

Conclusion

Oral RAE tube migration was not significantly correlated with the change in external TMD. Due to their large variability, changes in TMD were not useful predictors of RAE tube migration.

Assessment of three placement techniques for individualized positioning of the tip of the tracheal tube in children under the age of 4 years

BACKGROUND

Accurate positioning of the tip of the tracheal tube (tube tip) is challenging in young children. Prevalent clinical methods include placement of intubation depth marks, palpation of the tube cuff in the suprasternal notch, or deliberate mainstem intubation with subsequent withdrawal. To compare the predictability of tube tip positions, variability of the resulting positions in relation to the carina was determined applying the three techniques in each patient.

METHODS

In 68 healthy children aged ≤4 years, intubation was performed with an age-adapted, high-volume low-pressure cuffed tube adjusting the imprinted depth mark to the level of the vocal cords. The tube tip-to-carina distance was measured endoscopically. Thereafter, placements using (I) cuff palpation in the suprasternal notch and (II) auscultation to determine change in breath sounds during withdrawal after bronchial mainstem intubation were completed in random order.

RESULTS

Tube tip position above the carina was higher when using depth marks (mean = 36.8 mm) compared with cuff palpation in the suprasternal notch (mean = 19.0 mm). Variability, expressed as sd, was lowest with the mainstem intubation technique (5.2 mm) followed by the cuff palpation (7.4 mm) and the depth mark technique (11.2 mm) (P < 0.005).

CONCLUSION

Auscultation after deliberate mainstem intubation and cuff palpation resulted in a tube tip position above the carina that was shorter and more predictable than placement of the tube using depth markings.

A randomized, single-blinded, prospective study that compares complications between cuffed and uncuffed nasal endotracheal tubes of different sizes and brands in pediatric patients

STUDY OBJECTIVE

To compare any association between the problematic distal placement of cuffed and uncuffed nasal endotracheal tubes (NETTs) of different sizes and brands in pediatric patients.

DESIGN

Randomized, single-blinded, prospective study.

SETTING

Operating room at The Children's Hospital.

PATIENTS

Pediatric patients (aged 2-18 years) scheduled for dental surgery under general anesthesia whose American Society of Anesthesiologists physical status is not greater than 2.

INTERVENTION

Patients were randomly assigned to preformed cuffed (1) RAE (Ring-Adair-Elwyn) endotracheal tube by Mallinckrodt or (2) nasal AGT NETT by Rüsch.

MEASUREMENTS

The distance between the tube's distal end and the carina was measured using a fiber optic bronchoscope. Problematic placements were defined where the tip of the tubes was within 0.5 cm of carina.

MAIN RESULTS

The odds of a problematic placement was 7 times higher (95% confidence interval of odds ratio, 2.06, 23.4) in patients managed with cuffed tubes than those with uncuffed tubes (P = .002). The distance between the tip of cuffed NETT tubes and carina was significantly less than with uncuffed tubes.

CONCLUSIONS

The chances of possible complications were significantly higher with cuffed NETT. The NETT should be kept at least 0.5 cm above carina to avoid possible complications.