Using a nasopharyngeal airway during fiberoptic intubation in small children with a difficult airway

Review Airway management in pediatric patients with burn contractures of the face and neck

Burn injury is a common cause of trauma, non-fatal burn injuries are a leading cause of morbidity, and significant numbers of the victims are children. Scar contracture after burn injury can cause severe functional limitation, pain, aesthetic and psychological problems and patients may present for contracture release and reconstructive surgery. The aim of this systematic review was to identify research relevant to airway management of children with burn contracture of the face and neck with special emphasis on awake airway management and airway anesthesia, and synthesize results that can aid practice. Literature search was performed on Medline, PubMed, Cochrane Library, and Google Scholar with selected keywords. The search was restricted to human subjects of ≤18 year age, there was no language or time restriction and the final search was concluded in July 2021. The review included 41 articles involving airway management of 56 patients in 61 anesthesia episodes. Patients aged between 8 months to 18 years. Mask ventilation and direct laryngoscopy, video laryngoscopy, optical stylet, supraglottic airway, flexible scope intubation and tracheostomy, and extracorporeal membrane oxygenation were the devices and methods used for securing the airway and oxygenation while the patients were awake or after anesthesia induction. Detailed planning and patient preparation are the fundamentals of airway management of pediatric patients with burn contracture of the face and neck, awake airway management with airway anesthesia can be safely used in selected patients, this review provides information for good clinical practice and might serve to improve the care of such children.

Nasopharyngeal tubes in pediatric anesthesia: Is the flow-dependent pressure drop across the tube suitable for calculating oropharyngeal pressure?

BACKGROUND

Nasopharyngeal tubes are useful in pediatric anesthesia for insufflating oxygen and anesthetics. During nasopharyngeal tube-anesthesia, gas insufflation provides some positive oropharyngeal pressure that differs from the proximal airway pressure owing to the flow-dependent pressure drop across the nasopharyngeal tube (ΔP_NPT ).

AIMS

This study aimed to investigate whether ΔP_NPT could be used for calculating oropharyngeal pressure during nasopharyngeal tube-assisted anesthesia.

METHODS

In a physical model of nasopharyngeal tube-anesthesia, using Rohrer's equation, we calculated ΔP_NPT for three nasopharyngeal tubes (3.5, 4.0, and 5.0 mm inner diameter) under oxygen and several sevoflurane in oxygen combinations in two ventilatory scenarios (continuous positive airway pressure and intermittent positive pressure ventilation). We then calculated oropharyngeal pressure as proximal airway pressure minus ΔP_NPT . Calculated and measured oropharyngeal pressure couples of values were compared with the root mean square deviation to assess accuracy. We also investigated whether oropharyngeal pressure accuracy depends on the nasopharyngeal tube diameter, flow rate, gas composition, and leak size. Using ΔP_NPT charts, we tested whether ΔP_NPT calculation was feasible in clinical practice.

RESULTS

When we tested small-diameter nasopharyngeal tubes at high-flow or high-peak inspiratory pressure, proximal airway pressure measurements markedly overestimated oropharyngeal pressure. Comparing measured and calculated maximum and minimum oropharyngeal pressure couples yielded root mean square deviations less than 0.5 cmH₂ O regardless of ventilatory modality, nasopharyngeal tube diameter, flow rate, gas composition, and leak size.

CONCLUSION

During nasopharyngeal tube-assisted anesthesia, proximal airway pressure readings on the anesthetic monitoring machine overestimate oropharyngeal pressure especially for smaller-diameter nasopharyngeal tubes and higher flow, and to a lesser extent for large leaks. Given the importance of calculating oropharyngeal pressure in guiding nasopharyngeal tube ventilation in clinical practice, we propose an accurate calculation using Rohrer's equation method, or approximating oropharyngeal pressure from flow and pressure readings on the anesthetic machine using the ΔP_NPT charts.

The Pediatric Difficult Airway: Updates and Innovations

Children have unique characteristics that make them particularly vulnerable to perioperative adverse events. Skilled airway management is a cornerstone of high-quality anesthetic management. The use of hybrid airway techniques is a critical tool for the pediatric anesthesiologist. Point-of-care ultrasonography has an expanding role in airway management, from preoperative assessment of airway pathology and gastric contents to confirmation of tracheal intubation and identification of the cricothyroid membrane. The exciting fields of 3-dimensional printing, artificial intelligence, and machine learning are areas of innovation that will transform pediatric difficult airway management in years to come.

An Infant with Crouzon Syndrome Presenting with Reversible Chronic Airway Obstruction

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Temporomandibular Joint Ankylosis: "A Pediatric Difficult Airway Management"

Intubating a pediatric patient with temporomandibular joint ankylosis is a daunting task, and it becomes more challenging with limited mouth opening. Fiberoptic nasotracheal intubation technique is considered a gold standard. We describe an improvised technique of securing airway in the absence of appropriate-sized fiberoptic scope. The endotracheal tube inserted in the left nostril for maintaining depth of anesthesia was advanced under vision by the fiberoptic scope inserted into the right nostril, and with external laryngeal manipulation, the airway was secured with no complications.

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.

Randomized comparison of experts and trainees with nasal and oral fibreoptic intubation in children less than 2 yr of age

BACKGROUND

We hypothesized that the time to successful fibreoptic tracheal intubation through the nasal route would be faster than the oral route for both experts and trainees in children <2 yr of age.

METHODS

One hundred children, 24 months and under in age, were randomized to an operator (expert or trainee), and route (nasal or oral) for fibreoptic tracheal intubation. Three separate times were then measured: (i) time to first glottic view, (ii) time to carinal view, and (iii) total time to successful tracheal intubation. The number of attempts made, manoeuvres needed to obtain an adequate laryngeal view, and manoeuvres for tracheal tube passage were also recorded.

RESULTS

Time to successful tracheal intubation was significantly faster for experts than trainees. There was no difference in the time to tracheal intubation between the nasal and oral routes for experts. In trainees, intubation times were shorter for the nasal route-median (inter-quartile range) time (s) to carinal view was 35 (27-63) for the nasal route vs 59 (38-94) for the oral route (P=0.03), and the median time to successful tracheal intubation were 62 (49-122) vs 117 (61-224), P=0.05, for the nasal and oral routes, respectively. For trainees, the oral route required a greater number of airway manoeuvres for adequate laryngeal views and passage of the tracheal tube compared with the nasal route.

CONCLUSIONS

For clinicians with less experience in using paediatric bronchoscopes, fibreoptic tracheal intubation through the nasal route may be a more straightforward process than the oral route in children <2 yr of age.

CLINICAL TRIAL REGISTRATION

NCT02029300 (www.clinicaltrials.gov).

Pediatric airway management

Securing an airway is a vital task for the anesthesiologist. The pediatric patients have significant anatomical and physiological differences compared with adults, which impact on the techniques and tools that the anesthesiologist might choose to provide safe and effective control of the airway. Furthermore, there are a number of pathological processes, typically seen in the pediatric population, which present unique anatomical or functional difficulties in airway management. The presence of one of these syndromes or conditions can predict a "difficult airway." Many instruments and devices are currently available which have been designed to aid in airway management. Some of these have been adapted from adult designs, but in many cases require alterations in technique to account for the anatomical and physiological differences of the pediatric patient. This review focuses on assessment and management of pediatric airway and highlights the unique challenges encountered in children.

Children with Limited Oral Opening Can Be Safely Managed without a Tracheostomy

Objective

To describe airway management of children with limited oral opening that does not allow for routine orotracheal intubation by direct laryngoscopy. To analyze the incidence and outcome of airway compromise or loss in patients without a tracheostomy in place.

Study Design

Case series with chart review.

Setting

Tertiary children’s hospital.

Subjects

Children with limited oral opening that does not allow for routine orotracheal intubation.

Methods

Children treated at Children’s Hospitals and Clinics of Minnesota from 1997 to 2012 with severe trismus were identified and included in the study. Hospital and clinic records were reviewed.

Results

Ten children (mean age, 13 years; range, 7-17 years) were identified for inclusion into the study. A total of 109 operations requiring general anesthesia (average of 10.9 per patient; range, 0-23) were performed on patients without a tracheostomy in place. Flexible fiber-optic nasotracheal intubation was performed in 58 cases. The remainder of airway control was by mask ventilation (33 cases), various methods of orotracheal intubation (10 cases), unknown (6 cases), and laryngeal mask airway (2 cases). There was a total of 118 patient-years of follow-up without a tracheostomy tube in place (average of 11.8 years per patient). During this period, there were no episodes of acute airway compromise that resulted in neurologic deficits.

Conclusion

Children with limited oral opening that does not allow for routine orotracheal intubation with direct laryngoscopy may be safely managed without a tracheostomy, even when the child requires frequent procedures under general anesthesia.

[Anesthesia in spontaneous ventilation for difficult intubation]

Difficult intubation in children is rare and often predictable during anesthesia consultation. This allows to establish a strategy to provide fiberoptic guided tracheal intubation with spontaneous ventilation in function of age and children pathology. A good knowledge of physiologic and anatomic children particularities, of fiberoptic technique and the respect for some principles lead to ensure the security of this procedure. First principle is to use only one anesthetic inhaled or intravenous agent in order to limit an important decrease of ventilation. The anesthetic technique recommended for pediatric fiberoptic guided intubation is inhaled anesthesia with sevoflurane. But it is possible to use an intravenous agent, like propofol, with a continuous infusion (bolus of 0.1 to 0.3 mg/kg then 0.1-0.3mg/kg per hour for maintenance) or with target controlled infusion (Schnider model, initial concentration 2.5 μg/mL, then increase by 0.5 μg/mL steps) particularly in children older than 5 years with an anesthetic depth control. Whatever the agent, the dose must to be titrated to maintain spontaneous ventilation. Second principle is to combine an airway local anesthesia with general anesthesia to limit airway reactivity. First, a nose topical anesthesia is administered with lidocaine plus naphazoline in children older than 2 years. Then, a laryngeal topical anesthesia is realized with lidocaine 1% (1-2 mL, 2mg/kg) through operating channel of fiberoptic bronchoscope. Finally, third principle is to ensure patient oxygenation with several techniques like use of endoscopic facial mask or nasopharyngeal tube. The use of laryngeal mask is a rescue technique in case of spontaneous ventilation lost. In conclusion, each institution has to establish an algorithm with his own knowledge, constantly feasible and regularly taught.

Estimation of the nares-to-epiglottis distance and the nares-to-vocal cords distance in young children

BACKGROUND

Estimation of the nares-to-epiglottis and nares-to-vocal cords distances would facilitate the selection of properly sized nasopharyngeal airways and appropriate positioning of a fibreoptic bronchoscope in young children. The purposes of this study were to measure the nares-to-epiglottis and nares-to-vocal cords distances and to create an algorithm to predict these distances based on anatomical landmarks and paediatric characteristic data.

METHODS

Two hundred and eleven children, aged 1-10 yr, undergoing elective surgery were investigated. After induction of general anaesthesia, the distances from the nares to the epiglottis/vocal cords were measured using a nasogastric tube. After intubation, the distances from the lateral border of the nose to the ipsilateral mandible angle (nares-to-mandible distance) and the tragus of the ear (nares-to-tragus distance) were measured using a tape measure.

RESULTS

The nares-to-epiglottis and nares-to-vocal cords distances were significantly correlated with the age, weight, height, and external measurements (P<0.001). By stepwise multiple linear regression analysis, formulas were obtained for the nares-to-epiglottis distance (cm)=2.606+0.058×height (cm)+0.231×the nares-to-mandible distance (cm)-0.304 (gender) (r(2)=0.754) and for the nares-to-vocal cords distance (cm)=4.947+0.06×height (cm)+0.228×nares-to-mandible distance (cm)-0.283 (gender) (r(2)=0.803).

CONCLUSIONS

The nares-to-epiglottis and nares-to-vocal cords distances can be predicted using the height and the nares-to-mandible distance in young children.

CLINICAL TRIAL REGISTRATION NUMBER

Clinical Research Information Service KCT0000150.

Early release of interalveolar synechiae under general anesthesia through fiberscopic nasal intubation

This article presents a treatment strategy for early release of interalveolar synechiae, aiming to facilitate early oral feeding and prevent temporomandibular joint ankylosis.The treatment results of 2 patients with van der Woude syndrome were retrospectively studied. Both patients underwent early surgical release of interalveolar synechiae under general anesthesia through fiberscopic nasal intubation. The 2 patients were treated at the ages of 6 and 14 days, respectively. The interincisival distances increased from 5 and 6 mm preoperatively to 11 and 10 mm immediately after surgery. This was increased further to 25 and 20 mm at long-term follow-up (6 and 24 months).In conclusion, synechiae between the upper and lower jaws can be safely treated at a very early age under general anesthesia with fiberscopic nasotracheal intubation. The purpose of early intervention in these cases is to facilitate oral feeding and prevent temporomandibular joint ankylosis.

The management of difficult intubation in children

This article looks at the current techniques and equipment recommended for the management of the difficult intubation scenario in pediatric practice. We discuss the general considerations including preoperative preparation, the preferred anesthetic technique and the use of both rigid laryngoscopic and fiberoptic techniques for intubation. The unanticipated scenario is also discussed.

A simple fibreoptic assisted laryngoscope for paediatric difficult intubation: a manikin study

The fibreoptic assisted laryngoscope is a new airway device. We compared the fibreoptic assisted laryngoscope with the Bullard laryngoscope, Macintosh laryngoscope and fibreoptic bronchoscope in a manikin with a simulated Cormack and Lehane Grade 4 laryngoscopic view. Eighteen anaesthetists intubated the manikin's trachea using these devices and the success rate of intubation was measured. They were then asked to rate the subjective difficulty of intubation. The success rate (95% confidence interval) was 100% (94.6-100) with the fibreoptic assisted laryngoscope, 88.9% (80.5-97.3) using the Bullard laryngoscope, 37.0% (24.1-49.9) with the Macintosh laryngoscope, and 22.2% (11.1-33.3) using the fibreoptic bronchoscope. Tracheal intubation using the fibreoptic assisted laryngoscope or Bullard laryngoscope is easier than that using the Macintosh laryngoscope or fibreoptic bronchoscope by subjective difficulty score. All of the intubations were successful with the fibreoptic assisted laryngoscope without practice. These results suggest that fibreoptic assisted laryngoscope may be a useful tool for paediatric difficult intubation.

Paediatric airway management: basic aspects

Paediatric airway management is a great challenge, especially for anaesthesiologists working in departments with a low number of paediatric surgical procedures. The paediatric airway is substantially different from the adult airway and obstruction leads to rapid desaturation in infants and small children. This paper aims at providing the non-paediatric anaesthesiologist with a set of safe and simple principles for basic paediatric airway management. In contrast to adults, most children with difficult airways are recognised before induction of anaesthesia but problems may arise in all children. Airway obstruction can be avoided by paying close attention to the positioning of the head of the child and by keeping the mouth of the child open during mask ventilation. The use of oral and nasopharyngeal airways, laryngeal mask airways, and cuffed endotracheal tubes is discussed with special reference to the circumstances in infants. A slightly different technique during laryngoscopy is suggested. The treatment of airway oedema and laryngospasm is described.

Circulatory responses to fiberoptic intubation in anesthetized children: a comparison of oral and nasal routes

BACKGROUND

Previous studies have demonstrated a significant difference in the circulatory responses in adults to fiberoptic nasotracheal intubation (FNI) and fiberoptic orotracheal intubation (FOI). But, it is unknown whether there is a clinically relevant difference in the circulatory responses in children to these two intubation methods.

METHODS

In this randomized clinical study, we compared the arterial blood pressure and heart rate changes during FNI and FOI in 66 children, ASA physical status I-II, aged 3-9 yr scheduled for elective plastic surgery. After anesthesia induction with fentanyl-propofol and vecuronium, fiberoptic intubation was performed. Noninvasive arterial blood pressure and heart rate were recorded before (baseline values) and after anesthesia induction (postinduction values), at intubation, and every minute for the first 5 min after intubation. The maximum values of arterial blood pressure and heart rate during the observation were also recorded.

RESULTS

The total intubation time was significantly longer in the FNI group than in the FOI group. Both FOI and FNI caused significant increases in arterial blood pressure and heart rate compared with the baseline and postinduction values. Arterial blood pressure and heart rate at intubation and after intubation, and their maximum values during the observed periods were significantly lower in the FNI group compared with the FOI group. The times required to reach the maximum values of systolic blood pressure and heart rate were significantly longer in the FNI group than in the FOI group, but the times required for recovery of systolic blood pressure and heart rate to postinduction values were significantly shorter in the FNI group than in the FOI group. After the intubation, the times required to reach the peak levels of systolic blood pressure and heart rate were not significantly different between the two groups.

CONCLUSIONS

Both FOI and FNI can cause significant circulatory responses in healthy anesthetized children, and the circulatory responses to FNI are fewer and of a shorter duration than those to FOI.