Endotracheal Tube Size Research Articles

Prevention of Pediatric Drug Calculation Errors by Pre-Hospital Providers

Context: Calculating weight-based drug dosages for pediatric patients is difficult, with significant error potential. In the pre-hospital setting, few safeguards currently avert pediatric drug administration errors. Objective: To determine whether use of a protocol-specific pediatric code card can enable pre-hospital providers to calculate more consistently accurate weight-based drug dosages, volumes of administration, and age-appropriate endotracheal tube sizes. Design: Questionnaires containing sample calculations of medication dosages, volumes, and endotracheal tube sizes were administered to pre-hospital providers from June to November of 2006.

Can the Broselow Tape Be Used to Estimate Weight and Endotracheal Tube Size in Korean Children?

BackgroundThe Broselow pediatric emergency tape (BT) was developed to provide a length-based estimate of body weight and equipment size during resuscitation. ObjectivesTo conduct a validation study on the use of the BT in Korean children. MethodsAnesthesia records from children were retrospectively reviewed. The measured weights of the subjects were compared with the BT weight estimates by using Bland-Altman analysis. The accuracy of the BT and age-based formula in predicting the endotracheal tube (ETT) size were also compared. The authors drew a receiver operating characteristics (ROC) curve to evaluate the cutoff height that would be acceptable for the application of BT without error in Korean children. ResultsA total of 665 children (mean [± SD] age, 5.1 [± 3.3] years, 61.8% male) were enrolled. The average measured weight of the Korean children was 1.54 kg heavier than the BT estimates (95% CI = 1.24 to 1.85 kg). The BT estimates showed better agreement with the actually used ETT sizes than did the age-based formula estimates (86.9% vs. 34.9%, p < 0.001). The cutoff height of the ROC curve was 127.15 cm. When the BT was used in children who were shorter than the cutoff height, 98.8% of the enrolled children's estimated weights were within the limits of agreement. ConclusionsThe BT can be used in Korean children as a helpful adjunct during resuscitation to estimate the weight and ETT size.

A new expiratory support system for resolving air trapping in lungs during mechanical ventilation: A lung model study

The aim of the study was to assess a new expiratory support (ES) system in resolving air trapping in the lungs during mechanical ventilation. The ES system consisted of a cylinder and two valves that were connected to the ventilatory circuit. The movements of them were synchronized with the ventilator. The cylinder aspirated gas during expiration. We compared the effects of the ES on air trapping between a narrower and an ordinary size endotracheal tube (ETT) (internal diameter (ID): 5 and 8 mm). In addition, we compared the effects of the ES on air trapping between normal and high airway resistance of the lungs (5 and 20 cm H(2)O/L/s). The ventilatory settings were as follows: volume controlled ventilation with constant inspiratory flow rate; tidal volume, 0.5 L; inspiratory time, 1.0 s; expiratory time, 1.0, 1.5, or 2.0 s; and PEEP, 0 cm H(2)O. The ES normalized the end-expiratory alveolar pressure of the 5 mm ID ETT at a level similar to that of the 8 mm ID ETT. The ES also resolved the air trapping induced by the high airway resistance of the lungs. In conclusion, the ES system resolved the air trapping associated with a narrow endotracheal tube and high airway resistance of the lungs.

Predicting Endotracheal Tube Size by Length in Newborns

The objective of this study was to determine the relationship of length to endotracheal tube (ETT) size in newborns and to use this relationship to develop a tool for predicting ETT size. The study, a prospective derivation, and validation of a predictive model, took place in the neonatal intensive care units (NICUs) in two urban teaching hospitals. Subjects included: ETT derivation set − 39 intubated neonates admitted to the NICU; Validation set − 69 intubated newborns from the same NICU. Leak percentages were measured in intubated neonates where the actual ETT size did not correlate with the tape-determined ETT size. Interventions were length, weight, and leak measurements. A prototype tape was developed using the derivation set and published anthropometric studies. The accuracy of the tape was validated on a separate set of newborns. The average relative difference between tape-predicted weight and actual weight was 9.5% (confidence interval [CI] = 8.3–10.6%) and was evenly distributed throughout all the weight groups. The tape predicted actual ETT size in 96% of cases (CI 86.3–99.5%) and was correct within 1 tube size (1/2 mm) in 100% (CI 94.8–100%). The only error in prediction of ETT size was in underestimation. Length-based weight estimations were tested on 100 subjects and predicted actual weight within 20% in 94% of cases. We concluded that length is an accurate predictor of ETT size and weight in term and preterm newborns and may be useful in situations in which weights are unobtainable, such as emergency resuscitation.

Determination of Endotracheal Tube Size in a Perinatal Population

Determination of Endotracheal Tube Size in a Perinatal Population

Can the Broselow Tape Be Used to Estimate Weight and Endotracheal Tube Size in Korean Children?

The Broselow pediatric emergency tape (BT) was developed to provide a length-based estimate of body weight and equipment size during resuscitation. To conduct a validation study on the use of the BT in Korean children. Anesthesia records from children were retrospectively reviewed. The measured weights of the subjects were compared with the BT weight estimates by using Bland-Altman analysis. The accuracy of the BT and age-based formula in predicting the endotracheal tube (ETT) size were also compared. The authors drew a receiver operating characteristics (ROC) curve to evaluate the cutoff height that would be acceptable for the application of BT without error in Korean children. A total of 665 children (mean [+/- SD] age, 5.1 [+/- 3.3] years, 61.8% male) were enrolled. The average measured weight of the Korean children was 1.54 kg heavier than the BT estimates (95% CI = 1.24 to 1.85 kg). The BT estimates showed better agreement with the actually used ETT sizes than did the age-based formula estimates (86.9% vs. 34.9%, p < 0.001). The cutoff height of the ROC curve was 127.15 cm. When the BT was used in children who were shorter than the cutoff height, 98.8% of the enrolled children's estimated weights were within the limits of agreement. The BT can be used in Korean children as a helpful adjunct during resuscitation to estimate the weight and ETT size.

The Feasibility of Ultrasound to Assess Subglottic Diameter

In healthy patients, the narrowest diameter of the subglottic upper airway is the width of the air-column at the level of the cricoid cartilage. This diameter governs the selection of the endotracheal tube size, as excessive tube diameter may damage the tracheal mucosa leading to postextubation stridor or subglottic stenosis. Unfortunately, selecting endotracheal tube size based on height, weight, or age does not reliably lead to the proper tube. The knowledge of airway diameter, especially using a bedside noninvasive tool, could therefore be helpful in anesthesia and intensive care. We studied 19 healthy volunteers (27 +/- 3 yr, nine females) to compare the transverse diameter of the cricoid lumen assessed by ultrasonography and magnetic resonance imaging. We found a strong correlation between the two techniques (r = 0.99, P < 0.05) confirmed by Bland-Altman analysis with a bias of 0.14 mm, a precision of 0.33 mm, and limits of agreement of -0.68 mm/0.96 mm. In young healthy adults, ultrasonography appeared to be a reliable tool to assess the diameter of the subglottic upper airway.

Laryngo-tracheal stenosis following endotracheal intubation

Background: Despite significant improvements in the biocompatibility of materials used for tracheal tubes, laryngeal and tracheal lesions as long-term complications of artificial airways continue to be problematic in patients requiring prolonged airway support. Methods: We present a case of postintubation tracheal stenosis in a 63-year-old woman with a history of dyspnoea on exertion after a relatively short period of intubation. Endoscopic examination performed a few weeks later revealed a tracheal stenosis. Consequently, she underwent a tracheal resection and reconstruction with good overall result. Conclusions: We highlight the fact that some patients with airway narrowing could be misdiagnosed as having bronchial asthma. The incidence of airway stenosis is relatively low, but a history of artificial airway should always be obtained. Endotracheal tube size and cuff pressure vare considered as two major risk factors for laryngo-tracheal stenosis.

High-Fidelity Medical Simulation as an Assessment Tool for Pediatric Residents' Airway Management Skills

To evaluate high-fidelity medical simulation as an assessment tool for pediatric residents' ability to manage an acute airway. We performed a prospective, observational study in which 16 pediatric residents were consented and then brought to the medical simulation center. They were placed in 2 different computer-driven scenarios and asked to manage the cases. The first scenario was a 3-month-old infant with bronchiolitis and severe respiratory distress and was programmed to develop respiratory failure. The second case was a 16-year-old adolescent with alcohol intoxication and respiratory depression and was programmed for emesis and aspiration. Both cases included a nurse, parent, and intern. We recorded performance of predetermined critical actions and any harmful actions. There were 47 attempts at intubation with 27 successes (56%). Appropriate preoxygenation was performed in 15 (47%) of 32 cases. Appropriate rapid sequence induction was administered in 21 (66%) of 32 cases. Cricoid pressure was applied in 20 (63%) of 32 cases. End-tidal carbon dioxide detector was used in 11 (34%) of 32 cases. A nasogastric tube was placed in 14 (44%) of 32 cases. Harmful actions included rapid sequence induction administered before intubation equipment setup, bag-valve mask not connected to oxygen, inappropriate endotracheal tube size, pulling cuffed endotracheal tube out while inflated, and placing the laryngoscope blade on backwards. Our data identified many areas of concern with resident skills in managing an airway. This project suggests that high-fidelity medical simulation can assess a resident's ability to manage an airway as well as a program's effectiveness in teaching the skills necessary to manage an acute pediatric airway.

Appropriateness of Age-based Formula to Determine Endotracheal Tube Size in Korean Children

Background: Age-based formulae have been widely used to predict appropriate size of the endotracheal tube (ETT) in children. The objective of this study was to evaluate the effectiveness of formula (internal diameter (ID) (mm) = [age in years + 16]/4) in Korean children. Methods: Ninety children under 8 years who required intubation with the regular uncuffed ETT were included in the study. Appropriate sizes were to permit a gas leak at 10-25 cmH2O with positive pressure ventilation. Initial intubation was tried with predetermined size and ETT was adjusted to meet this guideline. Results: A range of three tubes around the predicted tube size covered 79 cases (88%), whereas one size predicted by the formula applied to only 29 cases (32%). The selection of ETT which is 0.5 mm larger than the predicted size could allow appropriate intubation in 41 (45.6%) patients. Conclusions: The age-based formula (ID (mm) = [age in years + 16]/4) could predict the appropriate tube size in less than one third our patients. Therefore, we recommend three sizes be available before endotracheal intubation.

The Effect of Tracheal Gas Insufflation on Gas Exchange Efficiency

Transtracheal gas insufflation (TGI) improves gas exchange efficiency, but is associated with hyperinflation, and usually requires ventilator adjustment to compensate for the increased gas flow. Although bidirectional TGI (Bi-TGI) minimizes hyperinflation, it does not preclude the need to reduce tidal volumes to prevent hyperinflation. A flow-compensation system was developed by Respironics (Murrysville, PA) to match TGI flows; however, neither that nor the efficacy of Bi-TGI have been tested in vivo. We tested the hypotheses that flow compensation allows for a constant minute ventilation; Bi-TGI produces less hyperinflation than does unidirectional TGI (Uni-TGI), and endotracheal tube size influences the degree of hyperinflation during TGI. Seven anesthetized intact dogs were studied during positive-pressure ventilation using the Respironics flow compensation system. Measurements were made during steady-state conditions at constant and measured levels of CO(2) production. Gas exchange efficiency (assessed by expired gas analysis for dead space) and hyperinflation (measured as an increase in pleural pressure) were compared during Bi- and Uni-TGI and for endotracheal tube sizes varying from 7 to 10F. Bi- and Uni-TGI could be delivered at constant minute ventilation without adjusting ventilatory setting when the flow compensation circuit was present. Uni-TGI produced more hyperinflation than did Bi-TGI with all sizes of endotracheal tube, and hyperinflation was universally present as tube size decreased to 7.5F. We conclude that this new flow compensation system allows for the delivery of TGI without the need for adjustments to the ventilator settings, and that Bi-TGI produces less hyperinflation than does Uni-TGI, even with small diameter endotracheal tubes.

Improving the Success of Retrograde Tracheal Intubation

We read with great interest the comments Dr. Nadarajan made regarding our study comparing two techniques for retrograde orotracheal intubation,1and we thank him for the consideration he gave to our work.1Regarding the causes of the failure, we agree that, if the endotracheal tube has not been positioned beneath the vocal cords, the catheter may be difficult to insert or placed in a wrong position, and tracheal intubation will fail. In our study, most of the failures were due to a supraglottic placement of the endotracheal tube as a consequence of a wrong position of the catheter. The size of endotracheal tube was adapted to the patient’s morphology to allow its easy insertion into the trachea, as mentioned in the guidelines related to the airway management edited by the French Society of Anesthesia and Intensive Care.2The rotation of the endotracheal tube was also used to help the right positioning of the bevel and facilitate its passage between the vocal cords. Also, as discussed in the article,1we believe that, in alive patients, the analysis of the expired gas at the extremity of the catheter may be of great importance to confirm the correct position of the catheter before removing the guide wire.The literature regarding the retrograde tracheal intubation is sparse, and to our knowledge, there is no study comparing cricoid and subcricoid approaches in terms of complications, morbidity, and mortality. The subcricoid approach, enhancing the distance between the vocal cords and the site of the puncture, has been proposed to decrease the incidence of accidental extubation during retrograde tracheal intubation.3If the incidence of failure is decreased, the safety of this approach remains questionable. Regarding the cricoid approach, some of the complications have been reported during minitracheostomy,4,5and one can suppose that an incision may be more deleterious than a puncture with a needle and the insertion of a guide wire. It is difficult to conclude that the subcricoid approach should be preferred to the cricoid approach for retrograde tracheal intubation, and there are some good reasons to recommend the cricoid approach.6Because of its superficial localization, the cricothyroid membrane is easy to localize, the risk of accidental puncture of the thyroid gland is very low, and finally, the cricoid approach is easy to learn because the puncture of the cricothyroid membrane is used for other purposes, such as cricoid local anesthesia.*Hopital General, Centre Hospitalier Universitaire de Dijon, Dijon, France. francois.lenfant@chu-dijon.fr

Use of the Broselow Tape May Result in the Underresuscitation of Children

The purpose of this study was to determine the concordance of the Broselow tape with the measured heights and weights of a community-based population of children, especially in light of the increase in obesity in today's children. The authors examined more than 7,500 children in a cross-sectional, descriptive study in two different cohorts of children to compare their actual weight with their predicted weight by a color-coded tape measure. In all patients, the percent agreement and kappa values of the Broselow color predicted by height versus the actual color by weight for the 2002A tape were 66.2% and 0.61, respectively. The concordance was best in infants, followed by school-age children, toddlers, and preschoolers (kappa = 0.66, 0.44, 0.39, and 0.39, respectively; percent agreement, 81.3%, 58.2%, 60.7%, and 64.0%, respectively). The tapes accurately predicted (within 10%) medication dosages for resuscitation in 55.3%-60.0% of the children. The number of children who were underdosed (by > or =10%) exceeded those who were overdosed (by > or =10%) by 2.5 to 4.4 times (p < 0.05). The tapes accurately predicted uncuffed endotracheal tube sizes when compared with age-based guidelines in 71% of the children, with undersizing (> or =0.5 mm) exceeding oversizing by threefold to fourfold (p < 0.05). The Broselow tape color-coded system inaccurately predicted actual weight in one third of children. Caregivers need to take into consideration the accuracy of this device when estimating children's weight during the resuscitation of a child.

Unexpected Tracheal Web Encountered During Difficult Intubation in the Operating Room

A 60-year-old woman was prepared for revision of a previous anterior lumbar interbody fusion. After induction of anesthesia, three attempts to pass decreasing sizes of endotracheal tubes remained unsuccessful. An LMA Fastrach was inserted to maintain ventilation. Upon examination of the trachea with a flexible fiberoptic bronchoscope via the LMA Fastrach, a tracheal web was visualized 1 cm below the true vocal cords. Intraoperative excision of the tracheal web by an otolaryngologist allowed for the passage of an endotracheal tube and the continuation of the planned surgery.

Determination of Endotracheal Tube Size in a Perinatal Population

This study aimed at correlating anatomical dimensions of the larynx and trachea to age and weight in a prenatal population. Endotracheal tube size determination was then proposed according to these considerations. Anatomical measurements were obtained during 150 fetal and infant postmortem examinations. The optimal endotracheal tube size was determined by three methods: clinically, by a pressure method using calibrated inextensible balloons, and anatomically by comparing the laryngotracheal perimeter to the tube perimeters. Based on these results, recommended tube sizes were calculated. In premature babies before 37 weeks gestation, the optimal tube size according to pressure estimation was significantly greater than that determined by anatomical measurement alone. This difference was no longer valid after 40 weeks gestation. This study identified the elasticity of laryngeal structures in premature babies, allowing intubation with tube sizes greater than predicted by anatomical measurements with an increasing injury risk located in the posterior part of the glottic plane. This elasticity disappears near 40 weeks gestation, and the injury risk then predominates in the subglottic region. These results lead the authors to recommend that the size of the endotracheal tube used in the perinatal population should be based on anatomical and experimental data to limit the injury risks.

Developmental anatomy of the airway

This article describes changes that occur in the larynx and trachea from birth to adolescence in order to provide a rational approach to airway management at different ages. The timing and evolutionary role of the descent of the larynx is described. Guidelines are given for selecting endotracheal tube size along with a discussion of why choosing the correct tube size is so important. Changes in relative head size, adenotonsillar hypertrophy and mandibular growth are also discussed. The article ends with hints and tips for successful intubation.

The Air-Leak Test Is Not a Good Predictor of Postextubation Adverse Events in Children Undergoing Cardiac Surgery

The air-leak test is recommended as a method of assessing the appropriate size of an uncuffed endotracheal tube (ETT) in children. The authors' primary objective was to determine whether the air-leak test would predict adverse events and reintubations after the removal of the ETT in children who have undergone cardiac surgery. Prospective, observational, clinical study. University tertiary care hospital. Ninety-four children <10 years of age undergoing elective cardiac surgery requiring cardiopulmonary bypass surgery. The attending anesthesiologist assessed air-leak pressure after intubation in the operating room (OR). In addition, the air-leak test was performed in 42 patients before extubation in the pediatric intensive care unit (PICU). The incidence of adverse events and the number of failed extubations were recorded after removal of the ETT. Eleven of the 94 patients were excluded from the study. Four (4.3%) of the patients died in the PICU before extubation, and 7 patients were excluded for other reasons. The median age of the 83 children was 0.9 years (range 0.01-9.6 years). The total incidences of postextubation adverse events and failed extubations were 30.1% and 8.4%, respectively. An audible air leak < or =25 cmH(2)O airway pressure during the OR phase or before removal of the ETT during the PICU recovery phase had no significant predictive value for the incidence of adverse events (p = 0.63) or reintubations (p = 1.0). The patients undergoing simple and complete operations compared with more complex and incomplete operations had significantly fewer postextubation adverse events (p = 0.03). Neonates did not have a higher risk for postextubation adverse events (p = 0.64) or reintubations (p = 0.26) than older children. The air-leak test did not predict an increased risk for postextubation adverse events and reintubations in children undergoing elective congenital heart surgery.

Comparison of airway size with some phenotypic parameters in Dalmatian puppies: a practical method to estimate endotracheal tube size

ObjectiveTo determine the relationship between 16 phenotypic parameters and the diameter of the tracheal lumen and endotracheal tube size (ETS) in Dalmatian puppies. Study designA prospective nonblinded study. AnimalsTwenty-nine Dalmatian puppies, <5 months of age, referred to the Veterinary Faculty Clinics, Burdur, Turkey. Materials and methodsThe diameter of the tracheal lumen was assessed using lateral cervical radiographs and the ETS was determined for each puppy. The relationships between ETS and body mass, age, dimensions of carpal and digital pads of the thoracic limb, length of the philtrum and the distance between the philtrum and lateral nasal edges were analysed statistically. ResultsThe linear relationships between the ETS and the vertical length of the fourth digital pad (r2 = 0.915), and body mass (r2 = 0.908) were higher than with other parameters. Two predictive formulae for ETS derived from regression lines are: ETS ± SE (0.20) = [body mass (kg) × 6/10]+2.5 and ETS ± SE (0.19) = [vertical length of fourth digital pad (cm) × 6] − 2. Conclusions and Clinical relevanceThese formulae provide a practical guide to ETS selection in Dalmatian puppies.

Effect of endotracheal suction on lung dynamics in mechanically-ventilated paediatric patients

Endotracheal suctioning is performed regularly in ventilated infants and children to remove obstructive secretions. The effect of suctioning on respiratory mechanics is not known. This study aimed to determine the immediate effect of endotracheal suctioning on dynamic lung compliance, tidal volume, and airway resistance in mechanically-ventilated paediatric patients by means of a prospective observational clinical study. Lung mechanics were recorded for five minutes before and five minutes after a standardised suctioning procedure in 78 patients intubated with endotracheal tubes < or = 4.0 mm internal diameter. Twenty-four patients with endotracheal tube leaks > or = 20% were excluded from analysis. There was a significant overall decrease in dynamic compliance (p < 0.001) and mechanical expired tidal volume (p = 0.03) following suctioning with no change in the percentage endotracheal tube leak (p = 0.41). The change in dynamic compliance was directly related to both endotracheal tube and catheter sizes. There was no significant change in expiratory or inspiratory airway resistance following suctioning (p > 0.05). Although the majority of patients (68.5%) experienced a drop in dynamic compliance following suctioning, dynamic compliance increased in 31.5% of patients after the procedure. This study demonstrates that endotracheal suctioning frequently causes an immediate drop in dynamic compliance and expired tidal volume in ventilated children with variable lung pathology, intubated with small endotracheal tubes, probably indicating loss of lung volume caused by the suctioning procedure. There is no evidence that suctioning reduces airway resistance.

Anesthetic management of bronchopleurocutaneous fistula - an alternate approach

To the Editor: A 48-yr-old man with a persistent left bronchopleurocutaneous fistula (BPCF) and empyema thoracis following pneumonectomy presented for bronchial stump closure and left thoracoplasty. The patient refused any attempts at awake intubation. He was placed in semi-recumbent position with the left side down after topicalization and mask induction. Right-sided double-lumen tube (DLT) placement was attempted while the patient was breathing spontaneously, but was unsuccessful in the absence of adequate muscle relaxation. Attempts to position a left bronchial blocker under fibreoptic guidance resulted in the balloon either slipping into the fistulous opening or backing up into the trachea. Advancing a single-lumen tube into the right main stem bronchus resulted in right upper lobe obstruction and attempted DLT insertion over a tube exchanger was also unsuccessful. When rescheduled, he was positioned and induced in the same manner as before and intubated with an 8.5 size endotracheal tube. Anesthesia was maintained with air, oxygen and sevoflurane using a Bain circuit, the patient breathing spontaneously. A triple-lumen central line and a transesopheal echocardiograph (TEE) were added to standard monitoring. The patient was positioned in the sitting position and stabilized in the appropriate frame, with his hands abducted and flexed forwards. The surgeon approached the BPCF through a left thoracotomy by transaxillary approach. Transtracheal jet-ventilation was delivered through the tip of a catheter placed above the level of fistula, to lessen the possibility of barotrauma. Anesthesia was maintained with an infusion of ketamine. During jet-ventilation PaO2 values were 80 to 90 mmHg while PaCO2 increased to 60 mmHg. The fistula was repaired and leak tested while purulent material from the left chest cavity was suctioned clean. Controlled ventilation restored blood gas levels towards normal. Left thoracoplasty was completed and the patient was extubated in the operating room. Postoperative pain control was achieved by a thoracic epidural catheter with continuous infusion of bupivacaine and fentanyl. While anesthetizing the patient with BPCF in the sitting position, oxygenation can be assured with jetventilation, and gravity aids in draining away purulent secretions from the trachea.1 CO2 accumulation can be managed by limiting the surgical time and establishing controlled ventilation at the earliest opportunity. Hypotension can be corrected with crystalloid infusion. The hazard of air embolism can be monitored with TEE and treated with a triple lumen central venous catheter.2 When conventional methods of pulmonary isolation fail, anesthesia and surgery pose unusual challenges during the operative management of BPCF.3,4 Careful planning and meticulous anesthetic management can transform a difficult case into a manageable one.