Evaluation of a new recommendation for improved cuffed tracheal tube size selection in infants and small children

The in-vitro performance of a modern portable respirator in different lung models and as an alternative intensive care respirator: A simulation based cohort study

BACKGROUND

Transporting ventilated patients safely and without loss of efficacy is a challenge. Portable ventilators are generally used to transport critically ill patients, but their performance is often limited.

OBJECTIVE

This study aimed to compare the in-vitro performance of a modern portable respirator with a modern intensive care respirator for different lung settings.

DESIGN

An in-vitro testing of a portable and an intensive care respirator.

SETTINGS

Anaesthesia Department at the University Children's Hospital Zurich.

MAIN OUTCOME MEASURES

The portable respirator Hamilton T1 was compared with the established intensive care respirator bellavista1000 (BV) while applying different settings with the ASL 5000 (ASL) device. The ASL can simulate neonatal, paediatric, and adult lung settings with normal or impaired lung function. Accuracy of delivered tidal volumes, proximal and distal airway pressures and mechanical lung properties were assessed.

RESULTS

Bland-Altman analyses showed higher accuracy for applied tidal volumes delivered by the portable respirator, 12.6% [95% confidence interval (CI) -8.9 to 34.2], compared with the intensive care respirator, 15.9% (95% CI -18.5 to 50.3). In neonatal and infant lung models particularly, the accuracy of delivered tidal volumes by the portable respirator, 13.2% (95% CI -8.9 to 35.3) was superior to those delivered by the intensive care respirator, 20.9% (95%CI -15.9 to 57.7). Lung compliance estimation was performed more accurately by the intensive care respirator, whereas the portable respirator measured airway resistance more accurately. However, both respirators showed only moderate overall accuracy when assessing lung mechanics.

CONCLUSION

The tested portable respirator proved to be a useful device for invasive ventilation of critically ill patients. The overall performance is non-inferior to a conventional intensive care respirator.

The C-MAC video laryngoscope helps presbyopic anesthetists to overcome difficulty in neonatal and infantile intubation: a randomized controlled trial

BACKGROUND

Endotracheal intubation (ETI) is a life-saving procedure that must be accurately carried on to guard against complications. Presbyopia leads to difficulty in viewing close objects and may obstacle proper intubation even with the best hands.

PURPOSE

This study supposed that the use of video-laryngoscope (VL) may provide better intubation conditions for presbyopic anesthetists and targets to evaluate the neonates and infants' intubation success rates (ISR) by anesthetists aged ≥ 45 years using the C-MAC VL compared to the standard laryngoscope (SL).

METHODS

Thirty-one neonates with an age of 18.2 ± 5.2 days and a body weight of 4.5 ± 0.3 kg and 103 infants aged 8.6 ± 1 months and weighing 9.4 ± 1.5 kg were randomly categorized into the SL group that received ETI using the SL and the VL group had intubated using the C-MAC® (Karl Storz, Germany) VL with the standard Miller blade and flexible Stylet (2 mm PORTEX® stylet; Smiths Medical International Ltd., UK) to strengthen the endotracheal tube (ETT) and adjust its curvature as C-shaped. The study outcomes included the frequency of successful intubation and the number of intubation attempts.

RESULTS

The ISR was significantly (P < 0.001) higher with significantly (P = 0.0037) lower frequency of using assistance maneuvers with VL. The mean score of the anesthetist's difficulty rating was significantly (P < 0.001) higher with SL (2.7 ± 2) than with VL (1.27 ± 1.27). Times for the full intubation process were significantly (P < 0.001) shorter with VL than SL. The 1st attempt success rate was significantly (P = 0.0195) higher with VL than SL (86.6% vs. 67.2%). The frequency of maneuver-related complications was insignificantly (P = 0.116) reduced with the use of VL (4.5%) than with SL (12%). The ISR showed a negative significant correlation (r=-0.973, P = 0.005) with the anesthetist's age.

CONCLUSION

Neonatal and infantile intubation using VL is feasible and easy to handle by aged anesthetists and allows higher ISR and 1st attempt rate with minimal need for external assistant maneuvers and maneuver-related complications. VL might be more appropriate for the presbyopic pediatric anesthetists than the SL.

LIMITATIONS

The limitations of the study are the small sample size of anesthetists and the use of one type of VLs.

Exchange rates of second generation Microcuff® pediatric endotracheal tubes in children weighing more than 3 kg : A retrospective audit

BACKGROUND

Cuffed endotracheal tubes (cETT) pose the potential advantage of an infrequent need for reintubation in pediatric patients compared to uncuffed tubes. The aim of this study was to investigate tube exchange rates using second generation Microcuff® pediatric endotracheal tubes (PET) with an adapted sizing recommendation in a large single institution cohort of children and to identify potential variables associated with an elevated risk of tube exchange.

METHODS

Patient data obtained from the electronic patient data management system of the Department of Anesthesia, University Children's Hospital Zurich, Switzerland, were retrospectively assessed for demographic and anthropometric information, size of the internal tube diameter used for positive pressure ventilation and divergence from the size recommendation chart.

RESULTS

Data from 14,188 children younger than 16 years (median 5.3 years) and weighing at least 3 kg who underwent oral or nasal tracheal intubation using second generation Microcuff® PET between 2009 and 2015 were included. Of 13,219 oral tracheal intubations 12,049 (84.9%) were performed according to the manufacturer's size recommendation and 1170 with divergent endotracheal tubes. The odds ratio (OR) of oral reintubation was 0.13% (95% confidence interval 0.08-0.22%) for cases using the manufacture's size recommendation correctly and 22.74% (95% confidence interval 20.42-25.23%) for patients intubated with a not recommended tube (p < 0.0001).

CONCLUSION

These findings indicate that the second generation Microcuff® PETs can be reliably used with low tube exchange rates across the entire pediatric age range when the tube size is selected according to the manufacturer's size recommendation chart. Adherence to the manufacturer's tube size recommendation is urgently advised.

[Characteristics of the fetal and infant respiratory system : What the pediatric anesthetist should know]

Respiratory complications are the most frequent incidents in pediatric anesthesia after cardiac events. The pediatric respiratory physiology and airway anatomy are responsible for the particular respiratory vulnerability in this stage of life. This article explains the aspects of pulmonary embryogenesis relevant for anesthesia and their impact on the respiration of preterm infants and neonates. The respiratory distress syndrome and bronchopulmonary dysplasia are highlighted as well as the predisposition to apnea of preterm infants and neonates. Due to the anatomical characteristics, the low size ratios and the significantly shorter apnea tolerance, airway management in children frequently represents a challenge. This article gives useful assistance and provides an overview of formulas for calculating the appropriate tube size and depth of insertion. Finally, the pathophysiology and adequate treatment of laryngospasm are explained.

Usefulness of C-curved stylet for intubation with the C-MAC® Miller videolaryngoscope in neonates and infants: a prospective randomized controlled trial

BACKGROUND

Optimizing endotracheal tube (ETT) shape is important for successful videolaryngoscope-aided intubation. This prospective randomized controlled study aimed to compare the tube-handling time between a C-curved and hockey stick-shaped stylet in infants and neonates using the C-MAC® videolaryngoscope Miller blade.

METHODS

A total of 110 infants (age < 1 year) were randomly assigned to either the hockey stick-curved stylet group (group H, n = 53) or the C-curved stylet group (group C, n = 57). The primary outcome was tube handling time after glottis visualization and the secondary outcomes were the total intubation time, incidence of successful intubation, initial tube tip location at the laryngeal inlet, and numerical rating scale for ease of intubation.

RESULTS

Tube insertion time and total intubation duration (both in seconds) were significantly shorter in group C than in group H (13.3 ± 8.9 vs. 25.1 ± 27.0, P = 0.002; 19.9 ± 9.4 vs. 32.8 ± 27.1, P = 0.001, respectively). Group C displayed a higher rate of intubation success within 30 s than group H (87.7% vs. 69.8%, P = 0.029). The initial tube tip was located at the center in 34 children in group C (59.6%) and 12 children in group H (26.1%, P < 0.001). Laryngoscope operators rated intubation as easier when provided with a C-curved stylet.

CONCLUSIONS

In neonates and infants, modification of the ETT shape into a C-curve may reduce tube handling time compared to the conventional hockey stick-shaped tube during intubation using a C-MAC® video laryngoscope Miller blade.

Pre-Extubation Cuffed Tube Leak Test and Subsequent Post-Extubation Laryngeal Edema: Prospective, Single-Center Evaluation of PICU Patients

OBJECTIVES

We performed our standard air leak, leak percentage, and cuff leak percentage tests in pediatric patients intubated with microcuff pediatric tracheal tubes (MPTTs) just before extubation. We examined the association between test findings and the subsequent occurrence of post-extubation laryngeal edema (PLE).

DESIGN

Prospective, single-center, observational study.

SETTING

PICU (June 1, 2020 to May 31, 2021).

PATIENTS

Pediatric patients intubated and scheduled for extubation during the day shift in the PICU.

INTERVENTIONS

Multiple pre-extubation leak tests were performed on each patient immediately before extubation. In our center, the standard leak test is positive if a leak is audible at 30 cm H 2 O applied pressure with the MPTT cuff deflated. Two other tests were calculated in the pressure control-assist control ventilator mode using the following formulas: leak percentage with deflated cuff = (inspiratory tidal volume [V t ]-expiratory V t ) × 100/inspiratory V t ; cuff leak percentage = (expiratory V t with inflated cuff-expiratory V t with deflated cuff) × 100/expiratory V t with inflated cuff.

MEASUREMENTS AND MAIN RESULTS

The diagnostic criteria for PLE was made by at least two healthcare professionals and included upper airway stricture with stridor-requiring nebulized epinephrine. Eighty-five pediatric patients (< 15 yr) who had been intubated for at least 12 hours using the MPTT were included. Positive rates for the standard leak, leak percentage (cutoff 10%), and cuff leak percentage (cutoff 10%) tests were 0.27, 0.20, and 0.64, respectively. The standard leak, leak percentage, and cuff leak tests showed sensitivities of 0.36, 0.27, and 0.55, respectively; and specificities of 0.74, 0.81, and 0.35, respectively. PLE occurred in 11 of 85 patients (13%), and there were no instances of needing reintubation.

CONCLUSIONS

The pre-extubation leak tests in current practice for intubated pediatric patients in the PICU all lack diagnostic accuracy for PLE.

Neonatal perioperative resuscitation (NePOR) protocol-An update

Unexpected cardiac arrest in the perioperative period is a devastating complication. Owing to immaturity of organ systems, and presence of congenital malformations, morbidity and mortality are higher in neonates. There is abundant literature about early recognition and management of perioperative adverse events in children, but similar data and guidelines for surgical neonates is lacking. The current neonatal resuscitation guidelines cater to a newborn requiring resuscitation at the time of birth in the delivery room. The concerns in a newborn undergoing transition from intrauterine to extra uterine life is significantly different from a neonate undergoing surgery. This review highlights the causes and factors responsible for peri-arrest situations in neonates in the perioperative period, suggests preoperative surveillance for prevention of these conditions, and finally presents the resuscitation protocol of the surgical neonate. All these are comprehensively proposed as Neonatal Peri-operative Resuscitation (NePOR) protocol.

Choice of the correct size of endotracheal tube in pediatric patients

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

Airway Management in Pediatric Patients: Cuff-Solved Problem?

Traditionally, uncuffed tubes were used in pediatric patients under 8 years in pursuit of reducing the risk of postextubation stridor. Although computed tomography and magnetic resonance imaging studies confirmed that the subglottic area remains the narrowest part of pediatric airway, the use of uncuffed tubes failed to reduce the risk of subglottic swelling. Properly used cuffed tubes (correct size and correct cuff management) are currently recommended as the first option in emergency, anesthesiology and intensive care in all pediatric patients. Clinical practice particularly in the intensive care area remains variable. This review aims to analyze the current recommendation for airway management in children in emergency, anesthesiology and intensive care settings.

Cuffed versus uncuffed endotracheal tubes for neonates

BACKGROUND

Endotracheal intubation is a commonly performed procedure in neonates, the risks of which are well-described. Some endotracheal tubes (ETT) are equipped with a cuff that can be inflated after insertion of the ETT in the airway to limit leak or aspiration. Cuffed ETTs have been shown in larger children and adults to reduce gas leak around the ETT, ETT exchange, accidental extubation, and exposure of healthcare workers to anesthetic gas during surgery. With improved understanding of neonatal airway anatomy and the widespread use of cuffed ETTs by anesthesiologists, the use of cuffed tubes is increasing in neonates.

OBJECTIVES

To assess the benefits and harms of cuffed ETTs (inflated or non-inflated) compared to uncuffed ETTs for respiratory support in neonates.

SEARCH METHODS

We searched CENTRAL, PubMed, and CINAHL on 20 August 2021; we also searched trial registers and checked reference lists to identify additional studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), quasi-RCTs, and cluster-randomized trials comparing cuffed (inflated and non-inflated) versus uncuffed ETTs in newborns. We sought to compare 1. inflated, cuffed versus uncuffed ETT; 2. non-inflated, cuffed versus uncuffed ETT; and 3. inflated, cuffed versus non-inflated, cuffed ETT.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal. Two review authors independently assessed studies identified by the search strategy for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We identified one eligible RCT for inclusion that compared the use of cuffed (inflated if ETT leak greater than 20% with cuff pressure 20 cm H₂O or less) versus uncuffed ETT. The author provided a spreadsheet with individual data. Among 76 infants in the original manuscript, 69 met the inclusion and exclusion criteria for this Cochrane Review. We found possible bias due to lack of blinding and other bias. We are very uncertain about frequency of postextubation stridor, because the confidence intervals (CI) of the risk ratio (RR) were very wide (RR 1.36, 95% CI 0.35 to 5.25; risk difference (RD) 0.03, -0.11 to 0.18; 1 study, 69 participants; very low-certainty evidence). No neonate was diagnosed with postextubation subglottic stenosis; however, endoscopy was not available to confirm the clinical diagnosis. We are very uncertain about reintubation for stridor or subglottic stenosis because the CIs of the RR were very wide (RR 0.27, 95% CI 0.01 to 6.49; RD -0.03, 95% CI -0.11 to 0.05; 1 study, 69 participants; very low-certainty evidence). No neonate had surgical intervention (e.g. endoscopic balloon dilation, cricoid split, tracheostomy) for stridor or subglottic stenosis (1 study, 69 participants). Neonates randomized to cuffed ETT may be less likely to have a reintubation for any reason (RR 0.06, 95% CI 0.01 to 0.45; RD -0.39, 95% CI -0.57 to -0.21; number needed to treat for an additional beneficial outcome 3, 95% CI 2 to 5; 1 study, 69 participants; very low-certainty evidence). We are very uncertain about accidental extubation because the CIs of the RR were wide (RR 0.82, 95% CI 0.12 to 5.46; RD -0.01, 95% CI -0.12 to 0.10; 1 study, 69 participants; very low-certainty evidence). We are very uncertain about all-cause mortality during initial hospitalization because the CIs of the RR were extremely wide (RR 2.46, 95% CI 0.10 to 58.39; RD 0.03, 95% CI -0.05 to 0.10; 1 study, 69 participants; very low-certainty evidence). There is one ongoing trial. We classified two studies as awaiting classification because outcome data were not reported separately for newborns and older infants.

AUTHORS' CONCLUSIONS

Evidence for comparing cuffed versus uncuffed ETTs in neonates is limited by a small number of babies in a single RCT with possible bias. There is very low certainty evidence for all outcomes of this review. CIs of the estimate for postextubation stridor were wide. No neonate had clinical evidence for subglottic stenosis; however, endoscopy results were not available to assess the anatomy. Additional RCTs are necessary to evaluate the benefits and harms of cuffed ETTs (inflated and non-inflated) in the neonatal population. These studies must include neonates and be conducted both for short-term use (in the setting of the operating room) and chronic use (in the setting of chronic lung disease) of cuffed ETTs.

Comparison of the efficacy and safety of cuffed versus uncuffed endotracheal tubes for infants in the intensive care setting: a pilot, unblinded RCT

OBJECTIVE

To study effectiveness and safety of cuffed versus uncuffed endotracheal tubes (ETTs) in small infants in the intensive care unit (ICU).

DESIGN

Pilot RCT.

SETTING

Neonatal and paediatric ICUs of children's hospital in Western Australia.

PARTICIPANTS

Seventy-six infants ≥35 weeks gestation and infants <3 months of age, ≥3 kg.

INTERVENTIONS

Patients randomly assigned to Microcuff cuffed or Portex uncuffed ETT.

MAIN OUTCOMES MEASURES

Primary outcome was achievement of optimal ETT leak in target range (10%-20%). Secondary outcomes included: reintubations, ventilatory parameters, ventilatory complications, postextubation complications and long-term follow-up.

RESULTS

Success rate (achievement of mean leak in the range 10%-20%) was 13/42 (30.9%) in the cuffed ETT group and 6/34 (17.6%) in uncuffed ETT group (OR=2.09; 95% CI (0.71 to 6.08); p=0.28). Mean percentage time within target leak range in cuffed ETT group 28% (IQR: 9-42) versus 15% (IQR: 0-28) in uncuffed ETT group (p=0.01). There were less reintubations to optimise size in cuffed ETT group 0/40 versus 10/36 (p<0.001). No differences were found in gaseous exchange, ventilator parameters or postextubation complications. There were fewer episodes of atelectasis in cuffed ETT group 0/42 versus 4/34 (p=0.03). No patient had been diagnosed with subglottic stenosis at long-term follow-up.

CONCLUSIONS

There was no difference in the primary outcome, though percentage time spent in optimal leak range was significantly higher in cuffed ETT group. Cuffed ETTs reduced reintubations to optimise ETT size and episodes of atelectasis. Cuffed ETTs may be a feasible alternative to uncuffed ETTs in this group of patients.

TRIAL REGISTRATION NUMBER

ACTRN12615000081516.

Effects of tip-manipulated stylet angle on intubation using the GlideScope® videolaryngoscope in children: A prospective randomized controlled trial

BACKGROUND

An optimal endotracheal tube curve can be a key factor in successful intubation using the GlideScope videolaryngoscope.

AIMS

This study aimed to evaluate the effects of tube tip-modified stylet curve on the intubation time in children.

METHODS

Children aged 1-5 years were randomly assigned to either the standard curve (group S, n = 60) or tip-modified curve (group T, n = 60) groups. In group S, the endotracheal tube curve was similar to that in the GlideScope. In group T, a point approximately 1.5 cm from the tube tip was additionally angled to the left by 15°-20°. The primary outcome was the total intubation time, and the secondary outcomes were incidence of successful intubation in the first attempt, number of additional manipulations of the stylet curve, and visual analog scale (VAS) score for the easiness of intubation.

RESULTS

The mean total intubation time was significantly longer in group S than that in group T (13.9 [10.8] vs. 9.0 [3.4] sec, mean difference, 4.9 s; 95% confidence interval [CI], 2.0-7.8; p = .001). All patients in group T were successfully intubated in the first attempt, whereas those in group S were not (100% vs. 93.3%, relative risk [RR], 0.11; 95% CI, 0.01-2.02; p = .1376). Three patients in group S could be intubated after modifying the ETT curve similar to that in group T. Operators reported that tracheal intubation was easier in group T than in group S (median [interquartile range] for VAS; 1 [1-2] vs. 2 [1-3]; p < .001).

CONCLUSIONS

Having additional angle of the endotracheal tube tip to the left could be a useful technique to facilitate directing and advancing endotracheal tube into the vocal cords.

Cuffed endotracheal tubes in neonates and infants of less than 3 kg body weight-A retrospective audit

BACKGROUND

Large prospective clinical studies have shown that modern cuffed pediatric tracheal tubes can be used safely, even in children weighing ≥3 kg. There is a growing interest in their use in children weighing <3 kg so that they, too, can benefit from the potential advantages, particularly the high probability of these tubes fitting into and sealing the pediatric airway at the first intubation attempt. This study aimed to find a cut-off body weight for procedures requiring a cuffed tracheal tube to seal the airway in children weighing <3 kg and to evaluate the frequency and predictive factors for the requirement to place a cuffed instead of an uncuffed tracheal tube.

METHODS

This study was a retrospective analysis of 269 children weighing 2000-2999 g, primarily intubated by pediatric anesthetists. Frequency of intubation with uncuffed Sheridan tubes versus cuffed Microcuff^® Pediatric Endotracheal Tube (PET) 3.0 mm ID was studied. Predictive variables were assessed by means of logistic regression analysis. The ROC curve for weight at intubation time and Youden index was calculated.

RESULTS

The 149 (55.4%) children were finally intubated with a cuffed tracheal tube. Logistic regression demonstrated that body weight at tracheal intubation and birth weight were the strongest predictors for the appropriateness of cuffed/uncuffed tracheal tubes. The threshold weight at tracheal intubation was 2700 g for a probability >50% of using a cuffed tracheal tube.

CONCLUSION

Half of the children weighing 2000-2999 g received a Microcuff^® PET 3.0 mm ID, especially those with a body weight above 2700 g. Because of the anatomical dimensions in patients with a body weight of 2000-2999 g, cuffed tracheal tubes with smaller outer diameters may be required to better fit their airways.

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.

Adrenergic Signaling in Muscularis Macrophages Limits Infection-Induced Neuronal Loss

Enteric-associated neurons (EANs) are closely associated with immune cells and continuously monitor and modulate homeostatic intestinal functions, including motility and nutrient sensing. Bidirectional interactions between neuronal and immune cells are altered during disease processes such as neurodegeneration or irritable bowel syndrome. We investigated the effects of infection-induced inflammation on intrinsic EANs (iEANs) and the role of intestinal muscularis macrophages (MMs) in this context. Using murine models of enteric infections, we observed long-term gastrointestinal symptoms, including reduced motility and loss of excitatory iEANs, which was mediated by a Nlrp6- and Casp11-dependent mechanism, depended on infection history, and could be reversed by manipulation of the microbiota. MMs responded to luminal infection by upregulating a neuroprotective program via β₂-adrenergic receptor (β₂-AR) signaling and mediated neuronal protection through an arginase 1-polyamine axis. Our results identify a mechanism of neuronal death post-infection and point to a role for tissue-resident MMs in limiting neuronal damage.

Correlation between correctly sized uncuffed endotracheal tube and ultrasonographically determined subglottic diameter in paediatric population

Background and Aims:

Conventional age-based formulae often fail to predict correct size of endotracheal tube (ETT). In this study, we evaluated usefulness of ultrasound in determining appropriate tube size and derived a formula which enables us to predict correct tube size.

Methods:

A total of 41 American Society of Anesthesiologists' physical status 1 and 2 children in the age group of 2–6 years, undergoing elective surgery under general anaesthesia with uncuffed ETT were included in the study. Ultrasonography (US) was used to measure the subglottic diameter after induction of anaesthesia. The trachea was intubated with an ETT that allowed an audible leak between 15–30 mmHg. Pearson's correlation was used to assess the correlation between US measured subglottic diameter (US-SD) with diameter of ETT used. Linear regression was used to derive a formula for predicting ETT size.

Results:

We found that US-SD and patient's age correlated well with actual ETT OD (r: 0.83 and 0.84, respectively). Age-based formula, ETT ID = (Age/3) +3.5 [r: 0.81] had better correlation with actual ETT OD than conventional age-based Cole's formula, i.e., ETT ID = Age/4 + 4 [r: 0.77]. Our results enabled us to derive a formula for selecting uncuffed ETT based on US-SD.

Conclusion:

Our study concludes that although US-SD correlates with actual tracheal tube used and may be useful in choosing appropriate size ETT, there was no difference in number of correct predictions of ETT size by US measurement, universal formula, and locally derived formula.

Tracheal tube cuff pressure monitoring: Assessing current practice in critically ill patients at Chris Hani Baragwanath Academic Hospital

Background

Intubated patients with a high tracheal tube cuff pressure (CP) are at risk of developing tracheal or subglottic stenosis. Recently an increasing number of patients have presented to our hospital with these complications.

Objectives

To determine the frequency of tracheal tube CP measurements and the range of CP and to explore nursing knowledge regarding CP monitoring.

Methods

Frequency of CP measurement was assessed using a prospective chart review, followed by an interventional component. In the final stage nurses completed a self-administered questionnaire.

Results

A total of 304 charts from 61 patients were reviewed. Patients' ages ranged from 1 to 71 years, with a male preponderance (1.5:1). The majority of charts (87%) did not reflect a documented CP measurement and only 12 charts showed at least one measurement per shift. Only 17% of recorded CPs were within the recommended range; 59% were too low. The questionnaire was completed by only 51% of the 75 respondents. Nursing experience ranged from 3 to 35 years and 92% of respondents were trained in critical care. Knowledge of current critical care CP monitoring guidelines was reported by 62% of the respondents (n=23/37). Only 53% (20/38) reported routinely measuring CP. Almost all respondents (94%) knew of at least one complication of abnormal CP.

Conclusion

Having a basic knowledge of CP measurement, having awareness of the complications of abnormal CP and the availability of national best practice guidelines did not translate into appropriate ICU practice. Research into effective implementation strategies to achieve best practice is needed.

Contributions of the study

Basic knowledge of cuff pressure measurement may not always result in best practice.Improvement in current practice requires research into effective implementation strategies.

Evaluating chewing function: Expanding the dysphagia field using food oral processing and the IDDSI framework

The dysphagia field is still in relative infancy with a sophisticated knowledge base amassed since the early 1980's. The desire to identify aspiration and prevent life threatening pneumonia has resulted in a focus on the complexities of swallowing liquids. However, humans also ingest saliva, food, and oral medications, with the potential for these substances to incompletely clear the pharynx, be aspirated or block the airway. Safe swallowing of solid food in particular requires adequate chewing function, good oral control, and sufficient higher cortical function. Although screening and assessment for liquid swallowing safety is well established, the same cannot be said for the evaluation of safety to chew and swallow different food textures. While research into liquid swallowing physiology and its clinical application has largely come from the medical and allied health fields, our knowledge of chewing function for food textures comes from food texture research and food sensory science arenas. There is an exciting opportunity to bring the medical and food texture science fields together to expand our knowledge base on human chewing function, with clinical application to people with dysphagia. The development of the IDDSI Framework as an international standardized way of describing and labelling food texture and drink thickness allows the field to move toward management of texture modified food and thick liquids in a coordinated fashion, speaking the same language. This commentary will describe what we know of chewing function and how it is assessed clinically, proposing methods of assessment that utilize the IDDSI Framework.

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.

Correlation between ultrasound-guided subglottic diameter and little finger breadth with the outer diameter of the endotracheal tube in paediatric patients - A prospective observational study

Background and Aims

Selection of an appropriate endotracheal tube (ETT) in paediatric patients is a challenging situation. The purpose of this study was to compare whether measurement of subglottic diameter with ultrasound or the age-old little finger width correlates better with the outer diameter (OD) of the ETT used for intubation.

Methods

Following approval from the Institutional Ethics board and a written informed consent from parent or guardian, this prospective observational study was carried out on 60 American Society of Anesthesiologists physical status I and II patients aged 6 months-8 years, scheduled for elective surgery under general anaesthesia requiring oral endotracheal intubation. Preoperatively ultrasound-guided subglottic diameter (USGD) and little finger breadth (LFB) measurements were taken. On the day of surgery, intubation was done with an uncuffed ETT, whose OD was noted. The concordance and agreeability between two techniques for estimation of the OD of the ETT were measured by Lin's concordance correlation coefficient. Further, the bias and precision between the techniques and the inter-changeability of the techniques were assessed by using Bland and Altman and Mountain plotting, respectively.

Results

Lin's concordance correlation coefficient between USGD and LFB with the OD of the ETT was found to be 0.29 (0.13-0.41) and 0.46 (0.29-0.6), respectively.

Conclusion

Overall, neither USGD nor LFB can be used as a reliable tool to predict the OD of the ETT. Registered in Clinical Trial Registry of India. REF/2016/08/011955.

Work of breathing for cuffed and uncuffed pediatric endotracheal tubes in an in vitro lung model setting

BACKGROUND

Over the last decade, cuffed endotracheal tubes are increasingly used in pediatric anesthesia and also in pediatric intensive care. However, the smaller inner diameter of cuffed endotracheal tubes and, implicitly, the increased endotracheal tube resistance is still a matter of debate.

AIMS

This in vitro study investigated work of breathing and inspiratory airway pressures in cuffed and uncuffed endotracheal tubes and the impact of pressure support ventilation and automatic tube compensation.

METHODS

In 5 simulated neonatal and pediatric lung models, the Active Servo Lung 5000 and an intensive care ventilator were used to quantify the differences in work of breathing under spontaneous breathing (with and without pressure support ventilation and automatic tube compensation) between cuffed and uncuffed endotracheal tubes. Additionally, differences in inspiratory airway pressures, measured either proximal or distal of the endotracheal tube, between cuffed and uncuffed endotracheal tubes under mechanical ventilation were investigated.

RESULTS

Work of breathing was overall 10.27% [95% confidence interval 9.01-11.94] higher with cuffed than with uncuffed endotracheal tubes and was dramatically reduced by 34.19% [95% confidence interval 31.61-35.25] with the application of pressure support. Automatic tube compensation almost diminished work of breathing differences between the 2 endotracheal tube types in nearly all pediatric lung models. Peak inspiratory and mean airway pressures measured at the proximal endotracheal tube end revealed significantly higher values in cuffed than in uncuffed endotracheal tubes. However, these differences measured at the distal end of the endotracheal tube became minimal.

CONCLUSION

This in vitro study confirmed significant differences in work of breathing and inspiratory pressures between cuffed and uncuffed endotracheal tubes. Work of breathing, however, is almost neutralized by pressure support ventilation with automatic tube compensation and distal inspiratory airway pressures that, from a clinical perspective, are not significantly increased.

Benefits of Using High-Volume-Low-Pressure Tracheal Tube in Children Undergoing Congenital Cardiac Surgery: Evidence From a Prospective Randomized Study

BACKGROUND

In the past 2 decades, usage of high-volume-low-pressure microcuffed tracheal tubes in smaller children has increased. However, there is paucity of evidence of its usage in smaller children undergoing congenital cardiac surgery. The aim of this study was to assess if microcuff endotracheal tubes in neonates and younger children undergoing congenital cardiac surgery is associated with better outcomes than uncuffed tubes.

METHODS

We carried out this single-center, prospective, randomized study between June and November 2016. Eighty patients were randomized into those receiving microcuff tracheal tubes and conventional uncuffed tubes. Primary outcome was stridor postextubation. Secondary outcomes measured included number of tube changes, volume of anesthetic gases required, and cost incurred.

RESULTS

The 2 groups were comparable in terms of baseline characteristics and duration of intubation. Incidence of stridor was significantly higher in conventional uncuffed tubes (12 [30%] vs 4 [10%]; P = .04) and so was the number of tube changes required (17/40 [42.5%] vs 2/40 [5%]; P ≤ .001). Tube change was associated with more than 3-fold risk of stridor (odds ratio = 3.92; 95% confidence interval = 1.23-12.43). Isoflurane (29.14 ± 7.01 mL vs19.2 ± 4.81 mL; P < .0001) and oxygen flow requirement ( P < .0001) and the resultant cost (7.46 ± 1.4 vs 5.77 ± 1.2 US$; P < .0001) were all significantly higher in the conventional uncuffed group.

CONCLUSION

Microcuff pediatric tracheal tube is associated with significantly lower incidence of stridor, tube changes, and anesthetic gas requirement. This leads to significant cost reduction that offsets the higher costs associated with usage of a microcuff tracheal tube.

Comparison of a paediatric emergency ruler with a digital algorithm for weight and age estimation

BACKGROUND

Emergency tapes like the "Paediatric-Emergency-Ruler" (PaedER) provide drug dosing and recommend medical airway equipment based on estimated patient bodyweight and age. Previous studies have revealed unsatisfactory accuracy in bodyweight estimation, due to the tapes' length-based weight categories. Therefore, we developed a digital algorithm allowing continuous length-based estimation of weight and age. The aim of this study was to compare the new algorithm with the PaedER regarding accuracy in estimating bodyweight and recommendation of medical airway equipment.

METHODS

Patients with a body length suitable for the PaedER were included in this single centre, prospective clinical observation trial after obtaining informed written parental consent. Bodyweight estimations by the algorithm and PaedER within ± 10% and ± 20% of the actual bodyweight were compared. Furthermore, medical airway equipment suggested by the PaedER and algorithm were compared with the equipment actually used for anaesthesia. Wilcoxon- and McNemar-Tests were used for statistical analysis. Results are median (interquartiles), P < 0.05 was considered significant.

RESULTS

In total, 489 patients aged 2.0 years (0.4-5.9), with a body length of 89.0 cm (63.5-114.5), weighing 12.8 kg (6.3-19.6), were included. The algorithm's precision of bodyweight estimation within ± 10%/± 20% was significantly higher at 64.0%/91.6% than the PaedER at 55.4%/81.8% (P < 0.001). Compared to PaedER the algorithm showed a higher incidence of correctly recommended medical airway equipment based on its accuracy for age and bodyweight estimation.

CONCLUSION

The new digital algorithm is an alternative to conventional emergency tapes, showing improved accuracy regarding length-based estimation of bodyweight and recommendation of medical airway equipment.

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

BACKGROUND

The aim of this prospective study was to investigate the success of ultrasound in pediatric patients in determining the appropriate sized cuffed endotracheal tube and to compare the results with conventional height-based (Broselow) tape and age-based formula tube size.

METHODS

One hundred and fifty-two children of 1-10 years of age, who received general anesthesia for adenotonsillectomy were enrolled to the study. In all participants, the transverse diameter of the subglottis was measured with ultrasound during apnea. An endotracheal tube was chosen with the outer diameter matched to the measured subglottic airway diameter. An age-based (Motoyama-Khine) and height-based (Broselow) endotracheal tube size was calculated. If there was resistance to passage of the tube into the trachea or an airway pressure >25 cmH₂ 0 was required to detect an audible leak, the endotracheal tube was replaced with internal diameter of 0.5 mm smaller. If there was an audible leak at airway pressure <10 cmH₂ O, or peak pressure >25 cmH₂ 0 or a cuff pressure > 25 cmH₂ O was required to seal, the tube was changed to the 0.5 mm larger internal diameter. Best-fit tube internal diameter was the resultant tube internal diameter that met the previously stated conditions. The need for endotracheal tube replacement and peak airway pressure were recorded.

RESULTS

The internal diameter of ultrasound determined tube was the same as best-fit tube in 88% of children. Endotracheal tube was replaced in 15 patients with a one size larger, and in three patients with one size smaller tube. Using Bland-Altman analysis, a better agreement was observed with ultrasound measurement rather than height-based estimation and age-based formulas.

CONCLUSION

Our findings show that subglottic diameter measured by ultrasound appears to be a reliable predictor for the assessment of the subglottic diameter of the airway in estimating appropriate size pediatric endotracheal tube.

Cuffed endotracheal tubes in children: the effect of the size of the cuffed endotracheal tube on intracuff pressure

BACKGROUND

In children, the size of the cuffed endotracheal tube is based on various age-based formulas. However, such formulas may over or underestimate the size of the cuffed endotracheal tube. There are no data on the impact of different-sized cuffed endotracheal tubes (ETT) on the intracuff pressure in children.

AIM

The current study measures intracuff pressure with different-sized cuffed ETT.

METHOD

The study was conducted in an in vitro and in vivo phase. For the in vitro phase, 10 cuffed ETT of size 4.0, 4.5, and 5 mm internal diameter (ID) each were randomly placed inside a 1.0 cm ID plastic tube (mimicking the trachea), which was in turn connected to a 1 l test lung. After inflation of the cuff using the air leak test at a continuous positive airway pressure of 20 cmH₂ O, the intracuff pressure was measured. The in vivo phase was conducted in 100 children (4-8 years) and were randomly divided into two groups to receive either a cuffed endotracheal tube based on the Khine formula (Group R) or a cuffed endotracheal tube that was a half-size (0.5 mm ID) smaller (Group S). Following the inflation of the cuff to seal the trachea, the intracuff pressure was measured.

RESULTS

In the in vitro phase, the intracuff pressure was 45 ± 6, 23 ± 1, and 14 ± 6 cmH₂ O with size 4.0, 4.5, and 5 mm ID cuffed ETT, respectively (F-test P < 0.001 for difference among three groups). In the in vivo phase, the mean intracuff pressure in Group R was 25 ± 19 cmH₂ O vs 37 ± 35 cmH₂ O in Group S (95% CI of difference: 1, 23; P = 0.039).

CONCLUSION

If the cuffed endotracheal tube is too small, the trachea can still be sealed by inflating the cuff with additional air. However, this transforms the cuff from the intended high-volume, low-pressure cuff to an undesirable high-volume, high-pressure cuff.

Development of International Terminology and Definitions for Texture-Modified Foods and Thickened Fluids Used in Dysphagia Management: The IDDSI Framework

Dysphagia is estimated to affect ~8% of the world's population (~590 million people). Texture-modified foods and thickened drinks are commonly used to reduce the risks of choking and aspiration. The International Dysphagia Diet Standardisation Initiative (IDDSI) was founded with the goal of developing globally standardized terminology and definitions for texture-modified foods and liquids applicable to individuals with dysphagia of all ages, in all care settings, and all cultures. A multi-professional volunteer committee developed a dysphagia diet framework through systematic review and stakeholder consultation. First, a survey of existing national terminologies and current practice was conducted, receiving 2050 responses from 33 countries. Respondents included individuals with dysphagia; their caregivers; organizations supporting individuals with dysphagia; healthcare professionals; food service providers; researchers; and industry. The results revealed common use of 3-4 levels of food texture (54 different names) and ≥3 levels of liquid thickness (27 different names). Substantial support was expressed for international standardization. Next, a systematic review regarding the impact of food texture and liquid consistency on swallowing was completed. A meeting was then convened to review data from previous phases, and develop a draft framework. A further international stakeholder survey sought feedback to guide framework refinement; 3190 responses were received from 57 countries. The IDDSI Framework (released in November, 2015) involves a continuum of 8 levels (0-7) identified by numbers, text labels, color codes, definitions, and measurement methods. The IDDSI Framework is recommended for implementation throughout the world.

Difficult tracheal intubation and post-extubation airway stenosis in an 11-month-old patient with unrecognized subglottic stenosis: a case report

Background

Subglottic stenosis can lead to life-threatening difficult tracheal intubation during general anesthesia. We report a case of difficult tracheal intubation in an 11-month-old female who had unrecognized subglottic stenosis.

Case presentation

The patient was scheduled for elective correction of a right accessory auricle. She was suspected of having first and second branchial arch syndrome. Preoperative physical examination was normal. Anesthesia was induced uneventfully using sevoflurane. It was not possible to pass size 4.0, 3.5, or 3.0 cuffed endotracheal tubes due to an advanced subglottic lesion. Subsequent successful intubation was achieved using a 3.0 uncuffed tube. Stridor was audible after extubation, and the patient required several days’ treatment with dexamethasone to address respiratory distress.

Conclusions

We encountered unrecognized subglottic stenosis that led to difficult tracheal intubation and post-extubation airway stenosis.

Use of cuffed tracheal tubes in neonates, infants and children: A practice survey of members of the Society of Pediatric Anesthesia

STUDY OBJECTIVE

This study aimed to characterize the current practice patterns with cuffed tracheal tubes (CTT) in neonates, infants, and children among members of the Society of Pediatric Anesthesia (SPA).

DESIGN AND SETTING

An electronic mail survey was distributed using Survey Monkey to members of SPA between December 2013 and February 2014. Each member was permitted one response.

PATIENTS/INTERVENTION/MEASUREMENTS

Not applicable as this is a practice survey study.

MAIN RESULTS

A total of 805 (28%) of the 2901 members of the SPA responded. Of the respondents, 88% were from the US, 83% were fellowship trained, 82% practiced pediatric anesthesia >50% of the time, and 65% practiced in academic centers. Eighty-five percent used CTT >50% of the time in children >2 years and 60% used CTT in full-term neonates >50% of the time. Twenty-nine percent reported always using CTT whereas 5% reported never using CTT. Those in practice <5 years, who were fellowship trained or in academic practice used CTT more often in neonates compared with those in practice >20 years, not fellowship trained or in private practice (P< .0001, P= .0003 and P= .0005, respectively). The most common reason for avoiding CTT was concern about post-extubation stridor (39%). Almost 70% of respondents accept the TT if it passes the subglottis without resistance and has a leak at 15 to 20 cmH2O. More than 60% of respondents do not monitor cuff pressures in CTT.

CONCLUSION

A majority of SPA members routinely use CTT in neonates, infants and children.

Cuffed endotracheal tubes in neonates and infants undergoing cardiac surgery are not associated with airway complications

STUDY OBJECTIVE

To determine the incidence of postoperative airway complications in infants <5kg in weight undergoing cardiac surgery intubated with Microcuff (Kimberley-Clark, Roswell, GA) endotracheal tubes (ETTs).

DESIGN

Retrospective review of infants weighing <5.0 kg with congenital heart disease (CHD) presenting for cardiac surgery.

SETTING

Single-center, tertiary pediatric cardiac critical care unit at a university hospital.

PATIENTS

A total of 208 infants weighing <5 kg underwent cardiac surgery for CHD from 2008 to 2013.

INTERVENTION

Intubation with Microcuff (Kimberley-Clark) ETTs.

STUDY DESIGN

Retrospective review of infants weighing <5.0 kg with CHD presenting for cardiac surgery to a single-center tertiary care university hospital.

MEASUREMENTS

Perioperative data were collected. Primary outcome was development of tracheal stenosis and/or reintubation for stridor. Stridor was defined as mild (≤2 doses of racemic epinephrine), moderate (>2 doses of racemic epinephrine), or severe (requiring reintubation). Secondary outcomes were variables possibly contributing to postextubation stridor. Infants with a tracheostomy, airway anomalies, and death prior to initial extubation were excluded. Logistic regression analysis was performed to evaluate the association between clinical risk factors and the incidence of postextubation stridor.

RESULTS

A total of 208 infants weighing <5 kg underwent cardiac surgery for CHD from 2008 to 2013; 12 subjects were excluded for death prior to initial extubation. No infant developed tracheal stenosis. The incidence of any stridor was 20.9% (95% confidence interval, 15.8%-27.1%) with severe stridor in 2 cases (1%). Age at surgery, weight, duration of intubation, dexamethasone use, and ETT size were not significantly associated with postextubation stridor. Presence of a comorbidity was significantly associated with stridor (P=.01).

CONCLUSIONS

Microcuff ETTs in infants <5.0 kg in weight undergoing cardiac surgery are associated with a low incidence of severe postextubation stridor. Because cuffed ETTs allow for improved control of ventilation/oxygenation and decreased risk of aspiration, they should be considered for use in this high-risk population. Larger studies are needed to confirm these results.

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.

Cuffed endotracheal tubes for neonates and young infants: a comprehensive review

Traditionally, uncuffed endotracheal tubes (ETTs) have been used for artificial ventilation of infants and children. More recently, newer designed high-volume low-pressure (HVLP) cuffed ETTs are being used with increasing frequency in infants from birth. Considering that many paediatric anaesthetists and intensivists are already using cuffed ETTs in infants >3 kg from birth, should neonatologists be doing the same? This review examines the reasons behind the traditional use of uncuffed ETTs and the problems associated with their use; newer HVLP cuffed ETTs and what they can potentially offer neonates; and reviews evidence from studies comparing the use of cuffed and uncuffed ETTs in neonates and small infants.

Use of Microcuff(®) endotracheal tubes in paediatric laparoscopic surgeries

BACKGROUND AND AIMS

Traditionally, uncuffed endotracheal tubes have been used in children. Cuffed tubes may be useful in special situations like laparoscopy. Microcuff(®) endotracheal tube is a specifically designed cuffed endotracheal tube for the paediatric airway. We studied the appropriateness of Microcuff(®) tube size selection, efficacy of ventilation, and complications, in children undergoing laparoscopy.

METHODS

In a prospective, observational study, 100 children undergoing elective laparoscopy were intubated with Microcuff(®) tube as per recommended size. We studied appropriateness of size selection, sealing pressure, ability to ventilate with low flow, quality of capnography and post-extubation laryngospasm or stridor.

RESULTS

Mean age of the patients was 5.44 years (range 8 months 5 days-9 years 11 months). There was no resistance for tube passage during intubation in any patient. Leak on intermittent positive pressure ventilation at airway pressure ≤20 cm H2O was present in all patients. Mean sealing pressure was 11.72 (1.9 standard deviation [SD]) cm H2 O. With the creation of pnemoperitoneum, mean intracuff pressure increased to 12.48 (3.12 SD) cm H2 O. With head low positioning, mean cuff pressure recorded was 13.32 (2.92 SD). Ventilation at low flow (mean flow 1 L/min), plateau-type capnography was noted in all patients. Mean duration of intubation was 83.50 min. Coughing at extubation occurred in 6 patients. Partial laryngospasm occurred in 4 patients, which responded to continuous positive airway pressure via face mask. Severe laryngospasm or stridor was not seen in any patient.

CONCLUSION

Microcuff(®) tubes can be safely used in children if size selection recommendations are followed and cuff pressure is strictly monitored. Advantages are better airway seal and effective ventilation, permitting use of low flows.

Cuffed tracheal tubes in children: past, present and future

This article reviews recent developments and core topics in the use and design of pediatric cuffed tracheal tubes. A concept for an appropriate pediatric cuffed tracheal tube is introduced. The main points in this concept are evidence-based tracheal tube size recommendation, continuous cuff pressure monitoring and a pediatric tracheal tube with an anatomically-based intubation depth mark and a short distally placed high-volume-low pressure cuff made from an ultra-thin polyurethane membrane with markedly improved tracheal sealing performance. The main points in proper handling of cuffed tracheal tubes in children are highlighted. Finally, an outlook on future developments in the design of pediatric cuffed tracheal tubes and an overview of tasks to be performed in evaluating them is given.

Pediatric cuffed endotracheal tubes

Endotracheal intubation in children is usually performed utilizing uncuffed endotracheal tubes for conduct of anesthesia as well as for prolonged ventilation in critical care units. However, uncuffed tubes may require multiple changes to avoid excessive air leak, with subsequent environmental pollution making the technique uneconomical. In addition, monitoring of ventilatory parameters, exhaled volumes, and end-expiratory gases may be unreliable. All these problems can be avoided by use of cuffed endotracheal tubes. Besides, cuffed endotracheal tubes may be of advantage in special situations like laparoscopic surgery and in surgical conditions at risk of aspiration. Magnetic resonance imaging (MRI) scans in children have found the narrowest portion of larynx at rima glottides. Cuffed endotracheal tubes, therefore, will form a complete seal with low cuff pressure of <15 cm H₂O without any increase in airway complications. Till recently, the use of cuffed endotracheal tubes was limited by variations in the tube design marketed by different manufacturers. The introduction of a new cuffed endotracheal tube in the market with improved tracheal sealing characteristics may encourage increased safe use of these tubes in clinical practice. A literature search using search words "cuffed endotracheal tube" and "children" from 1980 to January 2012 in PUBMED was conducted. Based on the search, the advantages and potential benefits of cuffed ETT are reviewed in this article.

Role of ultrasound compared to age-related formulas for uncuffed endotracheal intubation in a pediatric population

BACKGROUND

It is often difficult to determine the correct size of endotracheal tubes (ETT) needed for intubating pediatric patients. Therefore, we evaluated the role of ultrasound in pediatric patients to compare the correct size of an uncuffed (ETT) with the minimal transverse diameter of the subglottic airway (MTDSA) measured by ultrasound and with tube size predicted by different age-related formulas.

METHODS

A total of 50 pediatric patients ≤ 5 years were enrolled. As a standard, we defined the adequate ETT size with no audible leakage below a ventilation pressure of 15 mbar and with an audible leakage above 25 mbar. The maximum allowed difference between the prediction method result and the ETT that fit was defined as 0.3 mm. Ultrasound was performed before the intubation procedure; the intubating anesthesiologists were blinded to the results of the ultrasound measurement. Agreement between the two age-based formulas most commonly used at our department and MTDSA with the correct ETT size (standard) was analyzed using a Bland-Altman plot. Correlation and regression analyses were performed and the numbers of correct intubation trials recorded.

RESULTS

The frequency of bias ≤ 0.3 mm between each method and the correct ETT in the first attempt was <50% and the mean number of reintubations 1.6 ± 1.3. In contrast to age-related formulas, however, the ultrasonographically determined MTDSA was not significantly different from the correct ETT. MTDSA was highly associated with the outer diameter of the ETT (r = 0.869, R(2) = 0.754).

CONCLUSIONS

Measuring MTDSA by ultrasound facilitates selection of the appropriate ETT in pediatric patients and may reduce the number of reintubations.