The use of high‐flow nasal oxygen during airway management in a child with epidermolysis bullosa dystrophica and a difficult airway

Summary

The role of high‐flow nasal oxygen in paediatric anaesthesia has been emerging in recent years. However, literature regarding its benefits in paediatric difficult airway management is limited. In this case report, we describe the use of high‐flow nasal oxygen during airway management of a child with a difficult airway due to epidermolysis bullosa dystrophica in whom the use of a facemask would have been potentially harmful. Deep sedation was achieved with propofol and remifentanil while maintaining spontaneous breathing before flexible bronchoscopic tracheal intubation was attempted. However, on attempted tracheal intubation difficulty was encountered due to poor visualisation and contact bleeding. Tracheal intubation was eventually successful after converting to videolaryngoscopy. Oxygenation was maintained throughout the process despite deep sedation and a long procedure time. Moreover, no skin abrasions or mucosal injury resulted from the use of high‐flow nasal oxygen. We conclude that high‐flow nasal oxygen has a valuable role during airway management for a child with a predicted difficult airway when the use of a facemask would have been potentially harmful.

Introduction

The role of nasal continuous positive airway pressure (CPAP) or high‐flow nasal oxygen (HFNO) in paediatrics was established in managing patients with apnoea of prematurity, with data showing a promising effect 1. Recently, HFNO during anaesthesia has been a focus of novel research in adults with difficult airway and has been demonstrated to prolong apnoea time without hypoxia following induction of anaesthesia and before a definitive airway can be established 2. However, there are few publications regarding the use of HFNO in managing children with difficult airways 3.

Epidermolysis bullosa dystrophica is an autonomic recessive disease caused by the CLO7A1 gene mutation, resulting in defective production of type VII collagen which plays a crucial role in anchoring the basement membrane to the dermis. As a result, minimal shear force applied onto the skin can cause blister formation and subsequent scarring. Therefore, patients suffering from epidermolysis bullosa dystrophica may have a difficult airway due to facial scarring and meticulous precautions are required during anaesthesia to prevent further skin trauma 4, 5, 6.

In this case report, we describe the utilisation of the Airvo™ HFNO device (Fisher and Paykel Healthcare Limited, Auckland, New Zealand) to provide oxygenation during airway management for a child with epidermolysis bullosa dystrophica and a difficult airway.

Report

An 8‐year‐old boy was scheduled for bilateral syndactyly release, skin graft and K‐wire fixation. He was the first child of a consanguineous couple who have no family history of genetic diseases. He was born at full term following an uncomplicated pregnancy and epidermolysis bullosa dystrophica was diagnosed in the neonatal period. Generalised skin involvement of the disease resulted in severe limb contractures.

The patient had undergone multiple surgical procedures for skin grafting under general anaesthesia. During his last surgery a year previously, he was noted to have features of a difficult airway, especially restricted mouth opening from extensive peri‐oral scarring. At that time, a C‐MAC™ videolaryngoscope (Karl Storz, Tuttlingen, Germany) with a size 1 straight blade was used, which revealed a Cormack–Lehane grade 2a view.

During the pre‐operative assessment on this admission, features of a difficult airway were more pronounced (Fig. 1), including: limited mouth opening; minimal interincisor distance due to the growth of permanent incisors; and restricted neck movement from scarring. The plan was to perform flexible bronchoscopic tracheal intubation under sedation. Oral tracheal intubation was deemed to be preferable in order to minimise the risk of mucosal injury. Due to his limited mouth opening and the potential for airway damage, we designated videolaryngoscopy as the secondary plan. Contingency plans included ventilation through a well‐lubricated supraglottic airway device.

Figure 1.

Photographs of anatomical features of the patient's airway.

Precautions for managing an epidermolysis bullosa dystrophica patient were taken, including: generous use of lubricant; avoidance of sheer force; and meticulous handling and positioning. Before commencement of sedation, well‐lubricated Airvo™ nasal cannulae were applied with cut‐down defibrillation paddle gel pads placed under the tubing for protection. Furthermore, we ensured that the elastic used to secure the cannulae was slack and no pressure was exerted upon the patient's fragile skin. Junior mode on Airvo™ was selected with an initial F_IO₂ of 1.0 at a flow rate of 15 l.min⁻¹ for pre‐oxygenation, and the gas was humidified and warmed to 34°C. Propofol and remifentanil infusions were commenced and titrated with the aim of achieving an adequate depth of sedation while maintaining spontaneous breathing.

The maximum infusion rates were propofol 17 mg.kg⁻¹.h⁻¹ and remifentanil 0.2 μg.kg⁻¹.min⁻¹. As the depth of sedation was increased, the oxygen flow‐rate was gradually increased to 25 l.min⁻¹ based on the manufacturer's recommendations according to body weight. The oropharynx was topicalised with lidocaine 3 mg.kg⁻¹ via a mucosal atomisation device (MADgic™, Teleflex Medical, Athlone, Ireland) and a size 00 oropharyngeal airway was placed as a bite block to facilitate passage of a 3.1 mm flexible bronchoscope (Olympus Corporation, Tokyo, Japan). Spontaneous breathing was maintained throughout the attempts at flexible bronchoscope‐assisted tracheal intubation.

Flexible bronchoscopic tracheal intubation was unsuccessful due to poor visualisation, mucosal contact bleeding and difficulty in negotiating the bronchoscope. In order to avoid airway trauma, this approach was abandoned and we proceeded with a C‐MAC™ videolaryngoscope (Karl Storz, Tuttlingen, Germany). A size 1 straight blade could barely fit into the gap between the patient's premolars and the best laryngoscopic view was Cormack–Lehane grade 2b. The airway was finally secured with a size 4.5 microcuff tube with the aid of a stylet. A petroleum jelly‐soaked cotton tie was used to gently secure the tracheal tube, while gel pads were placed underneath the tie for additional skin protection. Forty‐six minutes elapsed between commencing airway management and successful tracheal intubation. The patient's oxygen saturations remained above 96% at all times and the first ET_CO2 reading after tracheal intubation was 9.1 kPa. Although some minor abrasions at the angle of mouth resulted from laryngoscopy, the use of HFNO caused no facial or mucosal abrasion.

Discussion

Since the introduction of trans‐nasal humidified rapid‐insufflation ventilatory exchange (THRIVE) 2, there has been a rapid expansion in the peri‐operatively use of HFNO, ranging from apnoeic oxygenation (THRIVE) to procedural sedation and the management of difficult airways 7, 8. The role of HFNO in paediatric anaesthesia is emerging, showing a promising role in providing apnoeic oxygenation 9 and managing patients with abnormal airways 3. Paediatric patients experience haemoglobin oxygen desaturation much more rapidly than adults due to their limited functional residual capacity and high metabolic rate, and a tendency for airway collapse 10. By providing uninterrupted high‐flow oxygen, that also provides some degree of CPAP that may help prevent airway collapse, HFNO has a potentially important role in managing difficult airways in paediatric anaesthesia.

In our patient with epidermolysis bullosa dystrophica and a difficult airway, we faced additional challenges which were mitigated by the use of HFNO as outlined in Table 1. In particular, we had to strike a careful balance between safely securing the airway and avoiding injury to his fragile skin and mucosa, which could cause further scarring. Moreover, due to his previous experience of multiple surgical procedures, the patient had developed an aversion to procedures such as facemask a pre‐oxygenation, with a consequent limitation of the available options for airway management. In the case of an epidermolysis bullosa dystrophica patient with a difficult airway where prolonged airway manoeuvres may be anticipated, the use of HFNO can avoid injury to facial skin due to accidental sheering forces during facemask ventilation. The option of awake tracheal intubation without sedation would have been impractical in this case due to the inevitable distress and discomfort.

Table 1.

Benefits of high‐flow oxygen in paediatric patients with epidermolysis bullosa dystrophica

Prolongs apnoeic time

Provides continuous positive airway pressure to prevent airway collapse

Reduces the need for potentially traumatic facemask ventilation

Reduces the need for an unsedated technique

Protects airway mucosa through humidification

Role in mask‐fear subjects

The decision to secure the airway under deep sedation was facilitated by the availability of HFNO. It provided continuous oxygenation and enabled an unhurried approach to intubation without traumatising the delicate airway. Furthermore, the humidification conveys further protection to the airway mucosa.

Regarding carbon dioxide clearance, we were unable to demonstrate a clear benefit with the use of HFNO in this case. Although THRIVE has been shown to reduce the rate of rise in partial pressure of carbon dioxide in apnoeic adults to between 0.17 and 0.22 kPa.min⁻¹ 2, 7, in children the rate of rise was found to be 0.32 kPa.min⁻¹ 9. Despite deep sedation, our patient maintained spontaneous ventilation throughout airway management, and the first ET_CO2 was noted to be 9.1 kPa, considerably higher than the normal range.

In summary, HFNO played a valuable role in providing continuous oxygenation during airway management for a child with a predicted difficult airway when the use of facemask would have been potentially harmful. Not only did it extend the window of safety for securing the airway in a gentle and cautious manner, it was also well‐tolerated even by a child who had developed an aversion to other pre‐induction anaesthetic equipment. However, the role of HFNO in carbon dioxide removal remains to be elucidated further.