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Craig Sims, Dana Weber and Chris Johnson (eds.) A Guide to Pediatric Anesthesiahttps://doi.org/10.1007/978-3-030-19246-4_17

17. Bronchoscopy and Removal of Foreign Bodies from the Trachea

Marlene Johnson¹ and Craig Sims¹

(1)

Department of Anaesthesia and Pain Management, Perth Children’s Hospital, Nedlands, WA, Australia

Marlene Johnson (Corresponding author)

Email: Marlene.Johnson@health.wa.gov.au

Craig Sims

Email: craig.sims@health.wa.gov.au

Keywords

Inhaled foreign bodies childrenStorz ventilating bronchoscopeOptical grasping forcepsAnesthesia for bronchoscopy

Bronchoscopy is performed to assess the airway in a child who has suspected laryngeal or tracheal anomalies, for investigation of stridor and obstruction, and for the removal of foreign bodies. Anesthesia is challenging as the airway is shared with the surgeon and unprotected.

17.1 Types of Bronchoscopes

There are many types of bronchoscopes used for assessment and management of airway conditions. Commonly used scopes include:

Ventilating bronchoscope (rigid)
Rod telescope (rigid)
Optical grasper (rigid)
Fiberoptic bronchoscope (flexible)

Each scope has distinct advantages and uses in specific scenarios, which are outlined below.

17.1.1 Storz Ventilating Bronchoscope

The most commonly used rigid bronchoscope is the Storz ventilating bronchoscope (Fig. 17.1). This is a hollow tube with a removable flat glass eyepiece at the proximal end. Next to the eyepiece are connectors for the fiberoptic light source and anesthetic gases, and a rarely-used port for suction or biopsy. The distal end is open and has fenestrations that allow for gases to pass if the distal scope is partly occluded.

../images/467929_2_En_17_Chapter/467929_2_En_17_Fig1_HTML.png — Fig. 17.1

The Storz ventilating bronchoscope and accompanying rod telescope

An anesthetic circuit can be connected to the side arm of the bronchoscope. A T-piece circuit is often preferred as it is lightweight and in close reach of the anesthetist. The circle circuit can be used, but there is uncertainty about how much gas passes through the filter into the patient rather than back down the expiratory limb of the circle. In addition, the APL valve is located at a distance on the anesthetic machine and needs to be frequently adjusted during ventilation because of the variable leak around the bronchoscope. When the eyepiece and instrument ports are occluded, manual ventilation through the side arm of the bronchoscope is possible.

The bronchoscope is available in a range of sizes. Careful attention must be paid to the size of the bronchoscope selected. Too large, and it will cause damage to the tracheal mucosa and mucosal edema; too small, and manual ventilation will be difficult. The correct size is one in which there is an air leak at 20 cmH₂O. Instruments, such as a rod telescope (see below), graspers or suction may be passed through the lumen of the Storz scope.

This scope is particularly useful for removing airway foreign bodies in the trachea and proximal bronchial tree. To retrieve a foreign body, the glass eyepiece is removed and a long forceps is passed down the lumen of the scope to grasp the foreign body. The view of the foreign body down the scope can be poor, as it is viewed down the length of the bore of the scope and the view is partly obscured when the forceps are inserted. The optical grasper (see below) gives a much better view and is growing in popularity among surgeons.

17.1.2 Hopkins Rod Telescope

The Hopkins rod telescope may be used alone or passed through the lumen of the ventilating bronchoscope to examine the larynx and trachea. The rod telescope is rigid, has its own light source and magnifies the view for the surgeon. It is much narrower than the Storz ventilating bronchoscope. Subsequently, it is likely to cause less damage to the mucosa and may be inserted further down the bronchial tree.

There is no gas channel on the rod telescope, so alternative methods to provide oxygen or anesthetic gases are required. Supplemental oxygen may be provided using nasal prongs. Alternatively, anesthetic gases and oxygen may be delivered through an ETT in the oropharynx or the nasopharynx.

When used in conjunction with the ventilating bronchoscope, it greatly narrows the lumen of the bronchoscope and increases the resistance to breathing. This is particularly a problem with the small bronchoscopes that are used in infants.

17.1.3 The Optical Grasper

The optical grasper is a rod telescope with distally placed forceps operated by a lever near the eyepiece (Fig. 17.2). Surgeons are using the optical grasper more frequently because it gives a clear, magnified view of the foreign body. However, it has no channel for anesthetic gases and ventilation through it is not possible. If the surgeon uses these forceps, a spontaneous ventilation technique must be used. This technique is described later in the section ‘Assessment of stridor’.

../images/467929_2_En_17_Chapter/467929_2_En_17_Fig2_HTML.png — Fig. 17.2

Optical grasper, which is similar to a rod telescope with grasping forceps attached. It is not possible to ventilate or insufflate gas with this instrument

Keypoint

Foreign body removal with a ventilating bronchoscope—spontaneous or controlled ventilation are possible. Foreign body removal with optical grasping forceps—spontaneous ventilation is the only option.

17.1.4 Fiberoptic Bronchoscope

A flexible fiberoptic bronchoscope is often used by respiratory physicians to perform diagnostic procedures. This is discussed further at the end of this chapter.

17.2 Inhaled Foreign Bodies

Inhalation of a foreign body is a potentially life-threatening event. A small reduction in airway radius will result in a large increase in resistance to airflow. Organic foreign bodies may result in airway hyper-reactivity as well as mucosal edema, which will cause further airway narrowing. These factors coupled with the high oxygen consumption of infants and small children cause hypoxia to occur rapidly. Inhaled peanuts are one of the most challenging foreign bodies to manage, as they cause local granulation and generalized tracheobronchitis within hours of aspiration. They may also fragment and be extremely difficult to remove.

The typical patient is a toddler or preschool-aged child. Children of this age are at higher risk because they display oral exploration behavior and lack molars for grinding food. The onset of symptoms is usually sudden. Following aspiration, there is great variation in the severity of airway obstruction ranging from asymptomatic to severe distress or asphyxia. Specific symptoms and signs will depend on the site, size and type of foreign body:

Signs of laryngeal or tracheal obstruction: coughing, choking, respiratory distress, cyanosis, stridor, tachypnea
Signs of obstruction of a main bronchus: respiratory distress, tachypnea, wheeze or absent breath sounds on the affected side

The larger the foreign body, the higher up in the airway it will have lodged and the more severe or life threatening the symptoms. However, there may also be no symptoms or signs if the item is small or not significantly occluding the airway. In these cases, it can be challenging to differentiate from other common pediatric respiratory conditions, such as croup, asthma and pneumonia. A thorough history from the caregiver is key.

Inspiratory and expiratory chest X-rays (CXR) and a lateral X-ray of the neck are performed as part of the diagnostic work up. However their diagnostic value is low. The CXR is often normal, and most foreign bodies aspirated by children are radiolucent. Air trapping with hyperinflation might be seen on the expiratory film due to a ‘ball valve effect’, but while this is the classical X-ray finding, it is not common and usually the chest X-ray is normal. The presentation may also be more chronic with a cough or chest infection, or with atelectasis or consolidation on the CXR. CT can also be considered, but may require sedation, and there are concerns about radiation exposure. Diagnosis from history and radiology can be challenging, and bronchoscopy is often required for both diagnosis and management (Fig. 17.3).

../images/467929_2_En_17_Chapter/467929_2_En_17_Fig3_HTML.png — Fig. 17.3

Classical CXR of an inhaled foreign body (FB) in the left main bronchus. The inspiratory film is normal, but on expiration there is obstructive emphysema with diaphragmatic, tracheal and mediastinal shift. The FB itself is usually radiolucent. It is more common however to find a normal CXR

It is preferable that the child is fasted before anesthesia as the airway cannot be fully protected during the procedure. Clearly however, the risk of waiting needs to be balanced against the fasting duration. Anesthesia of a small child for bronchoscopy and removal of a foreign body is difficult. It is preferable to have two anesthetists, one of whom should be well trained in pediatric anesthesia.

17.3 Anesthetic Techniques for the Removal of Foreign Bodies in Children

Although children are at greater risk of developing laryngospasm or hypoxia during bronchoscopy compared to adults, they are easier to keep motionless under anesthesia without muscle relaxants and there is usually an adequate seal to allow ventilation with a ventilating bronchoscope (Table 17.1). Sedative premedication should only be used if the benefits outweigh the risk of its effects on respiratory function. This depends on the degree of respiratory distress and the anxiety of the child. Anticholinergic agents can be used to dry the airway but are not routinely necessary with current agents and techniques. The anesthetic issues specific to bronchoscopy are listed in Table 17.2. One hundred percent oxygen is used throughout the procedure to avoid hypoxia caused by obstruction, hypoventilation and one lung ventilation during endobronchial scope placement.

Table 17.1

Anesthetic technique for rigid bronchoscopy and removal of foreign body—differences between adult and pediatric patients

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Nov 27, 2021 | Posted by admin in ANESTHESIA | Comments Off

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Bronchoscopy and Removal of Foreign Bodies from the Trachea