Pediatric Tracheostomy

Anatomy and Physiology

The trachea is a partially flexible tube measuring approximately 1.5 to 2 cm in width and 10 to 13 cm in length in the adult. The trachea extends from the lower part of the larynx, at the sixth to the seventh cervical vertebra, to the level of the fourth or the fifth thoracic vertebra, where it divides into the two mainstem bronchi. The tracheal wall comprises approximately 20 incomplete hyaline cartilage rings, forming the anterior and lateral circumference. The posterior side of the trachea is smooth muscle surrounded by a fibrous membrane of elastic connective tissue. The smooth muscle contains longitudinal and transverse fibers; the transverse fibers comprise the trachealis muscle and connect the posterior ends of the cartilaginous rings.[3]

The anatomy and physiology of the pediatric and adult trachea differ in clinically meaningful ways. Pediatric patients have a larger head-to-body ratio, a prominent occipital protuberance, and a shorter neck, all of which make patient positioning during tracheostomy more challenging. Additionally, infants and children have larger tongues and smaller mandibles than adults. Research shows that the adult airway is more elliptical than the pediatric airway. The larynx also sits at a higher level in children, and the location of the cricoid cartilage varies with age—at birth, it is at the C4 vertebral level, while in adults, it is at C6.[4] 

The vocal cords are not positioned perpendicular to the trachea; they are inclined towards the anteroinferior to the posterosuperior direction. The epiglottis is U-shaped in pediatric patients and may obstruct the laryngeal inlet. The narrowest point of the airway for children is at the cricoid cartilage level, while for adults, it is at the vocal cords level. The cartilaginous part of the airway in children is softer and more flexible than in adults; this increases the risk of obstruction during negative pressure ventilation, especially if there is a preexisting partial airway obstruction. The mucous membrane covering the supraglottic and subglottic areas of the airway is loose in infants and more susceptible to edema when injured or inflamed.

Significant changes in somatic and functional development are particularly observable in the airways, with notable transformations from the nasal passages to the alveoli, particularly during the first 2 years of life. As children age, the distinctions between pediatric and adult airways become less prominent. The respiratory system of a 6- to 8-year-old child closely resembles that of an adult.[5]

The trachea in children has characteristics distinct from the adult trachea. The pediatric trachea is shorter, narrower, and angled towards the back. Due to the higher position of the larynx in pediatric patients, the cervical segment of the trachea appears to have more cartilaginous rings than an adult. Newborns typically have 10 tracheal rings proximal to the sternal notch, while adolescents have 8, and adults have 6 or fewer. Furthermore, in infancy, the size of the trachea is approximately 50% of the length, 36% of the diameter, and 15% of the cross-sectional area of an adult trachea.

The growth pattern of the trachea is still a subject of debate. Previous research in 1986 by Griscom et al analyzed the trachea of 130 children younger than 6 years using computed tomography (CT) imaging. Their research described how the length, diameter, and cross-sectional area of the trachea change from birth to adolescence. Their findings indicated that by the end of adolescence, the length of the trachea doubles, and the mean transverse diameter is greater than the mean anteroposterior diameter until 6 years of age. These diameters continue to increase throughout childhood and adolescence, gradually becoming nearly equal, resulting in a rounder cross-section of the trachea. Around the age of 18 years, the anteroposterior diameters typically become slightly larger.[6]

Initially, it was believed that the tracheal growth pattern had a direct linear relationship from approximately 18 weeks of gestation until age 14 years in girls. In boys, tracheal enlargement, but not lengthening, continued after growth in height stopped. However, Luscan et al have recently demonstrated a tracheal development pattern similar to that of height and confirmed that the trachea does not have a round shape.[7]

Indications

The primary goals of pediatric tracheostomy are to establish a secure airway, improve ventilation, and promote recovery.[1]

Critically premature infants and those of any age with complex cardiopulmonary conditions like bronchopulmonary dysplasia have improved survival rates in recent years. As care for premature and medically complex neonates has improved worldwide, the main indication for pediatric tracheostomy is the need for prolonged ventilation.[8]

Other common indications for tracheostomy in children include:

• Benign airway tumors, such as recurrent respiratory papillomatosis
• Cervical tumors compromising the integrity of the trachea, such as cystic hygroma[9]
• Conditions that intrinsically or intrinsically obstruct the airway
• Congenital anatomical abnormalities such as bilateral vocal cord paralysis, laryngomalacia, and subglottic web[10]
• Infectious diseases compromising the airway, including epiglottitis and laryngotracheobronchitis
• Pulmonary toilet[11]
• Syndromes with airway anomalies, such as Treacher-Collins, Nager, or Beckwith-Wiedemann syndromes, or the Robin sequence[12]
• To assist in weaning from the ventilator[13][14]
• To prevent laryngotracheal stenosis in situations of long-term intubation[15]
• To prevent aspiration secondary to an unprotected airway, such as a laryngeal cleft or bulbar palsy[16]
• To provide ventilatory access in cases of difficult intubation, as seen in retropharyngeal abscess, post-tonsillectomy bleed, obstructive sleep apnea, tracheal foreign body, or facial burns

Contraindications

There is no absolute contraindication to tracheostomy. Relative contraindications to tracheostomy may be due to comorbidities or procedure-specific. 

General medical conditions or comorbidities that are relative contraindications to tracheostomy include coagulopathy, severe medical instability, and poor long-term prognosis.[17]

Procedure-specific relative contraindications to tracheostomy include an anterior cervical mass, a difficult surgical approach due to distorted or difficult anatomy, a high-riding innominate artery, and local infection.[18][19][1][20]

Equipment

The necessary instruments and equipment for tracheostomy may be divided into various categories for ease of memory.

For the safety of patients and healthcare workers, informed consent must be obtained, and personal protective equipment comprising a mask, gown, glove, and eye protection must be utilized.

Proper patient positioning requires a sandbag of appropriate size, a neckroll, and a head ring.

Intraoperative patient monitoring and confirmation of tube placement requires pulse oximetry, capnometry, a fiberoptic bronchoscope, and a stethoscope. Emergency airway equipment, a crash cart, and resuscitation equipment must always be available.

Equipment specific to the pediatric tracheostomy procedure includes:

• 5- and 10-ml syringes
• Functioning suction apparatus and catheters of different sizes
• Kidney tray, sponge holder, and dressing gauge
• Scalpel with an 11- or 15-blade
• 2 Langenbach retractor of small size
• Small- and medium-sized artery forceps
• Cricoid hook
• Tracheal forceps and dilators
• Tracheostomy tubes of various sizes
• Sutures, needle holders, and tracheostomy tapes[21]

Personnel

Essential personnel for performing a pediatric tracheostomy include:

• Primary surgeon
• Surgical first assistant
• Anesthetist
• Surgical technician or operating room nurse
• Circulating or operating room nurse
• Occupational therapy assistant or respiratory therapist

Preparation

Ensuring that all equipment is available and fully functional is essential. Informed consent must be obtained before the procedure.

Standard American Society of Anesthesiologists (ASA) monitors are attached after receiving the patient in the operating theater. General anesthesia should be administered according to the preference of the anesthetist, and orotracheal intubation should be performed.

The patient should be positioned supine with a sandbag between the shoulder blades and the neck extended over a roll or pillow to bring the trachea close to the skin of the neck.

Technique or Treatment

After induction of general anesthesia, microlaryngoscopy and bronchoscopy (MLB) may be performed to evaluate the airway. This evaluation aids in determining an appropriate tracheostomy size. Once deemed necessary, a cuffed endotracheal tube of the proper size is inserted and secured. The patient's position is adjusted with a small shoulder roll to extend the neck.

The sternal notch, cricoid cartilage, and thyroid cartilage are landmarks to determine the midline.

Following preparation and draping in the usual sterile fashion, a horizontal or vertical skin incision is made below the cricoid cartilage, typically between the second and fourth tracheal rings. The subcutaneous fat is removed above the strap muscles. The strap muscles are divided, allowing visualization of the laryngotracheal structure. At this point, monopolar electrocautery is discontinued.

Non-absorbable "rescue" or "stay" sutures are placed bilaterally, slightly away from the midline, over the intended tracheostomy site. Stay sutures can assist in elevating the trachea during stomal maturation and guide tube placement. Before making the tracheal incision, stomal maturation can be provided by suturing the peristomal skin to the tracheal perichondrium using absorbable sutures in a half-mattress fashion at four quadrants.[1] Optionally, if a horizontal skin incision is made, the lateral edges of the skin can be primarily closed at this stage. If stomal maturation has not yet been performed, it can be carried out after the tracheal incision by suturing the skin to the trachea using simple interrupted sutures. It should be noted that the tracheal incision is typically made vertically between the second and third or third and fourth tracheal rings. The choice depends on the relevant anatomy. The length of the tracheal incision should allow for smooth tracheostomy insertion without resistance.

IPOG (International Pediatric Otolaryngology Group) recommends using stay sutures in all cases, considering stomal maturation, complete airway endoscopy during the same anesthesia, and potential postoperative flexible tracheoscopy to verify proper tube placement. Their review did not address the specific technique for making the tracheal incision.[22]

The anesthetist is asked to withdraw the endotracheal tube below the vocal cords. At this point, the appropriate-size tracheostomy tube is placed inside the tracheal lumen and connected to the ventilatory circuit. The endotracheal tube is kept in its place till the proper position of the tracheostomy tube is confirmed. The distal end of the tracheostomy tube is kept approximately 2 or 3 rings above the carina, which can be confirmed with the flexible fibreoptic bronchoscope. The tracheostomy tube is secured around the neck with tracheostomy ties, and stay sutures are labeled as right or left around the incision and are taped on the anterior chest wall. These stay sutures help rapidly identify newly created stomas in case of accidental decannulation.[1]

Complications

Only 0.2% of hospitalized patients within pediatric referral hospitals undergo tracheostomy. The mortality rate among children with a tracheostomy varies and has been reported to be as high as 20%. The primary cause of mortality is substantial underlying health conditions. However, direct procedure-related complications and mortality have become increasingly rare. 

Complications associated with adult tracheostomy are reported in up to 15% of patients.[23] However, data regarding complications related to a pediatric tracheostomy is lacking. Up to 19% of children will have a tracheostomy-related complication.[24] Medical comorbidities frequently cause postoperative morbidity and mortality, while complications directly related to the device are infrequent. Complications may be mild, require no intervention, or be life-threatening. The most common causes of death in children due to tracheostomy are tube obstruction, tube misplacement, and accidental decannulation.

Complications of tracheostomy may be considered early or delayed.

Early Complications

From 3% to 9 % of tracheostomies in pediatric patients are associated with subcutaneous emphysema, pneumothorax, or pneumomediastinum. As a result, upon return to the floor unit, chest radiography is routinely advised to confirm tube placement and evaluate the condition of the chest.

Intraoperative bleeding can be stopped with judicious use of cautery and particular attention to hemostasis. Most commonly, the bleeding is in the form of capillary ooze from the thyroid gland or inferior thyroid vein. Still, significant hemorrhage can occur from aberrant vessels or vascular anomalies. Children with coagulation abnormalities or thrombocytopenia should undergo thorough evaluation before the tracheostomy.

Injury to surrounding structures can be avoided with careful surgical technique, identifying the cricoid cartilage and tracheal ring before making an incision; an incision on the cricoid cartilage may result in subglottic stenosis.[25] Injury to the recurrent laryngeal nerves and esophagus has been reported during pediatric tracheostomies.[26]

The sudden relief of upper airway obstruction due to tracheostomy may result in re-expansion pulmonary edema in pediatric patients. The rapid washout of retained carbon dioxide and loss of ventilatory drive may result in respiratory arrest during tracheostomy.[25]

Injuries may occur during the placement of the tracheostomy tube. The creation of a false passage may occur if the tracheostomy tube is pushed forcefully or the tracheal incision is too small. These circumstances may also lead to laceration of the posterior wall of the trachea, and sometimes larger size tubes may result in cannulation of the mainstem bronchus.

Accidental decannulation can happen in the immediate postoperative period and be prevented by proper patient positioning and the correct selection of size and placement of a tracheostomy tube.

Mucous plugs may obstruct the tracheostomy tube resulting in respiratory distress. Such complications can be prevented by proper stoma care, humidification, and regular tube changes.

Delayed Complications

Friction due to movement of the tracheostomy tube and chronic inflammation may lead to the development of peristomal granulation tissue. This complication can be prevented by local wound care and regular tracheostomy tube and dressing changes.[27] 

The formation of scar tissue around the stoma may lead to difficulty in changing the tube; the stoma sometimes requires surgical revision and excision of scar tissue.

Tracheocutaneous fistulae are formed when there is an apposition of skin to the tracheal mucous membrane. This is very common in chronically tracheostomy-dependent children. Also common is the formation of a suprastomal granuloma, which can be diagnosed by fibreoptic bronchoscopy.[28] Erosion of the posterior wall of the trachea and the anterior wall of the esophagus from the distal end of the tracheostomy tube may lead to the development of a tracheoesophageal fistula. It is one of the delayed complications of tracheostomy in children.

Longstanding pressure on the first and second tracheal rings can lead to the development of chondritis and the weakening of the tracheal ring, ultimately resulting in tracheomalacia in the suprasternal region.[29] High tracheostomy tube placement in the airway may result in subglottic stenosis. Other contributing factors are prolonged endotracheal intubation and chronic inflammation. Subglottic stenosis can be prevented by careful tube placement and stoma care.[30]

Swallowing problems may occur secondary to anchoring the trachea to the strap muscles. The cuff of the tracheostomy tube may increase pressure in the esophagus and hypopharynx, causing dysphagia. Tracheostomy should not be considered a contraindication to oral feeding.

Clinical Significance

Tracheostomy is one of the most important surgical procedures performed on children. Tracheostomy has become a viable intervention for a clinical condition requiring prolonged mechanical ventilation with the benefit of reducing airway resistance, reducing the need for deep sedation, improving patient comfort, and allowing for proper airway care. Anesthesiologists, pediatricians, and otolaryngologists must understand the indications, contraindications, and adverse effects of the procedure.

Enhancing Healthcare Team Outcomes

Tracheostomy in the pediatric population is not a benign procedure. It is believed that most deaths after tracheostomy are not due to the procedure itself but an underlying chronic condition, most likely the condition mandating tracheostomy. Complications associated with tracheostomies are well documented, with approximately 20% of patients suffering from some form of tracheostomy-associated complication.[24] Children with tracheostomy require complex care, and they need the coordination of pulmonologists, pediatricians, anesthetists, otorhinolaryngologists, cardiologists, respiratory therapists, primary care practitioners, nurses, neurologists, and equipment specialists to promote a better outcome. Many pediatric patients with tracheostomy suffer from disorganized care and poor communication between different specialties resulting in poor patient outcomes.

Various studies have demonstrated that tracheostomy-related adverse events can be significantly reduced by implementing tracheostomy care teams.[31][32] Data from the previous decade on adult tracheostomy has shown that well-coordinated interprofessional tracheostomy care can significantly reduce adverse events and improve patient outcomes.[33][34][35]

The International Pediatric Otolaryngology Group published recommendations in 2016 for the perioperative care of pediatric patients with tracheostomy.[36] The recommendations targeted pediatric patients with recent tracheostomies and included preoperative, intraoperative, and postoperative care, sedation, enteral feeding algorithms, and bedside information sheets. Although no studies have been conducted to validate such recommendations, they are an important step in standardizing pediatric tracheostomy care.