Clinical review of adult tracheostomy.
Abstract: Tracheostomy is a surgical procedure which is increasingly being performed in the intensive care unit (ICU) rather than the operating room (Griffiths et al 2005, Delaney et al 2006). Procedural knowledge including postoperative care is essential for ENT surgeons and ICU practitioners alike. Our article aims to highlight the operative technique, surgical complications and various types of tracheostomy tubes available, including their management.

KEYWORDS Tracheostomy / Tube types / Complications
Subject: Tracheostomy (Health aspects)
Postoperative care (Analysis)
Intensive care units (Management)
Authors: Vallamkondu, Vamsidhar
Visvanathan, Vikranth
Pub Date: 05/01/2011
Publication: Name: Journal of Perioperative Practice Publisher: Association for Perioperative Practice Audience: Academic Format: Magazine/Journal Subject: Health; Health care industry Copyright: COPYRIGHT 2011 Association for Perioperative Practice ISSN: 1750-4589
Issue: Date: May, 2011 Source Volume: 21 Source Issue: 5
Topic: Event Code: 200 Management dynamics Computer Subject: Company business management
Geographic: Geographic Scope: United Kingdom Geographic Code: 4EUUK United Kingdom
Accession Number: 272168013
Full Text: Introduction

The use of tracheostomy has increased over recent years. Traditionally, it was confined to the emergency management of upper airway obstruction however, with the advent of positive pressure ventilation, tracheotomy became an elective procedure following intubation. Today, owing to the advancements in intensive care and the widespread use of mechanical ventilation, tracheostomy is one of the most commonly performed surgical procedures and is encountered on a regular basis by hospital physicians in all fields. Therefore, knowledge of the surgical procedure including postoperative care is essential for all grades of surgeons and nursing staff in ENT wards and ICU. This review article targets this group of health care providers in supplementing the basic knowledge of surgery and its postoperative management.

Definition

Tracheotomy is the surgical opening of the trachea, whilst tracheostomy is creating an opening in the anterior tracheal wall and converting it into a stoma.

History

The procedure dates back to 2000 BC and is scripted in RIGVEDA, the ancient Hindu book of medicine, but it was associated with a high mortality level (Goodall 1994). During the 20th century, Chevalier Jackson popularised the surgical technique and his principles remain in practice even now. In the 21st century the procedure is performed at the bedside in the most critical care units, which reduces the risks associated with patient transfer and releases operating room resources, including time and personnel.

Anatomy

The trachea is a cartilaginous and membranous tube about 11cm in length which extends from the lower border of the cricoid cartilage to the carina. It is membranous posteriorly, and formed by semicircular cartilaginous rings anteriorly and laterally.

Anteriorly, the trachea is covered by skin, superficial fascia, deep fascia and strap muscles (sternohyoid and sternothyroid). The thyroid isthmus usually lies over the 2nd and 3rd tracheal rings. Anterior relations to the trachea in the lower neck and in the superior mediastinum include the inferior thyroid veins, the thyroid ima artery and thymus.

The left bracheocephalic vein may project upwards into the neck to form an anterior relation to the trachea and is at risk of injury during tracheostomy. Paratracheal structures vulnerable to injury include the recurrent laryngeal nerves and carotid sheath.

Physiological effects of tracheostomy

* Normal functions of the larynx such as cough and phonation are lost.

* Reduction in respiratory dead space results in reduced breathing effort compared to nasal or oropharyngeal breathing.

* Nasal mucociliary function is lost (filtration and humidification of inspired air) which results in drying and crust formation.

Indications

The indications for tracheostomy as defined by the American Academy of OtolaryngologyHead and Neck Surgery in the 2000 clinical indicators compendium (Archer et al 2000) are listed below:

* Upper airway obstruction with any of the following:

* Stridor

* Air hunger

* Retractions

* Obstructive sleep apnoea with desaturation

* Bilateral vocal cord paralysis

* Previous neck surgery or throat trauma

* Previous neck irradiation

* Prolonged or expected prolonged intubation

* Inability of patient to manage secretions including the following:

* Aspiration

* Excessive bronchopulmonary secretions

* Facilitation of ventilation support

* Inability to intubate

* Adjunct to manage head and neck surgery

* Adjunct to manage significant head and neck trauma.

Contraindications

Absolute contraindications for tracheostomy are soft tissue neck infections or anatomic aberrations which completely obscure the anatomy.

Surgical technique

The neck is extended by positioning the patient supine with a shoulder bag and a head ring. Care is taken to avoid hyperextension which can complicate into low tracheostomy. This increases the risk of decannulation in the early postoperative period. Depending on the indication for tracheostomy, the procedure is performed either under a local or general anaesthetic. The landmarks to be identified include the thyroid notch, cricoid cartilage and suprasternal notch. The incision site is marked halfway between the cricoid cartilage and suprasternal notch. Local anaesthetic infiltration may be used to assist surgical dissection through tissue planes and provide post operative analgesia.

Most authors (Johnson et al 1984, Myers 1998, Weight & Nicholson 2000) recommend a horizontal incision, yet this area is open to debate. Kirchner (1986) recommends a vertical incision to aid mobilisation of the tracheotomy tube with swallowing. However a vertical incision is more appropriate in infants and children. In this age group, the pleura apices may extend superiorly into the neck: a vertical skin incision minimises the need for dissection lateral to the trachea, and thereby reduces the risk of pneumothorax.

The incision is extended through the subcutaneous tissue, platysma through to deep cervical fascia. The midline raphe is incised and strap muscles retracted. Depending on the surgeon's preference, the thyroid isthmus is either retracted superiorly or divided. Meticulous haemostasis is essential throughout the procedure. The tracheotomy should be sited over the 2nd/3rd or 3rd/4th tracheal cartilages. Creating a tracheotomy over the first ring should be avoided as this risks the development of a subglottic stenosis.

Once a tracheotomy is performed, the endotracheal tube (ETT) is slowly withdrawn under direct vision ensuring that it lies just above the superior margin of the tracheotomy wound. This facilitates securing the airway immediately if there arises any problem with the positioning of the tracheostomy tube. An appropriate sized tube is inserted and connected to the ventilator.

Correct placement is confirmed by direct visualisation, end-tidal CO2, ease of ventilation and adequate oxygen saturation (Cameron 2008). The tracheostomy wound is closed with monofilament sutures.

Postoperative care

Trained personnel with adequate experience in managing complications of tracheostomy should be available at all time. Although basic nursing skills provide holistic care, specialist training is necessary when, for example, selecting the most appropriate tracheostomy tube, changing a tube or knowing when to start the process of tube removal. The tracheostomy nurse specialist can provide this expert knowledge and is fast becoming an important member of the multidisciplinary team.

The tube acts as a foreign body and therefore patients are prone to develop viscid secretions around the tube which risk tube blockage. Due to these factors, regular suction clearance and humidification are extremely important.

The cuff should remain inflated as long as there is a risk of aspiration. After an uncomplicated procedure, the cuff rarely needs to remain inflated for more than 12 hours. Tube change should occur once a tract is formed and this usually occurs between 48 and 72 hours. If the tube needs to be replaced early, tube change should be performed by a practitioner who is trained in the technique.

The tracheostomy tubes

Tracheostomy tubes can be plastic (polyvinyl chloride or silicone) or metal (silver or stainless steel). The various types of tubes include: cuffed, uncuffed, fenestrated, unfenestrated, variable length, single lumen and double lumen tubes. All tracheostomy tubes include an obturator to assist tube insertion (Hess 2005).

Tubes are available with a single or dual cannula. Dual-cannula tubes possess an inner cannula which aids cleaning to prevent gradual tube blockage. Disadvantages include a smaller internal diameter, which increases the work of breathing and paradoxically traps secretions.

Cuffed tubes

Cuffed tubes (Figure 1) are used for the first few days after a tracheostomy. The cuff provides an airway seal and reduces aspiration of orotracheal secretions (Loh & Irish 2002). Cuffs are typically low-pressure high-volume. This allows a wider distribution of pressure on the trachea and reduces the incidence of tracheal ulceration or stenosis. A complication of a cuffed tube is an impaired swallow mechanism due to the anchorage of the inflated cuff on the larynx. Higher pressures can decrease capillary blood flow and cause mucosal ischemia. A manometer should be used to measure cuff pressure. Myers et al (1998) recommended that the optimum cuff pressure should be in the range of 15-25cmH2O (10-18mmHg) to minimise the tracheal damage.

Fenestrated tubes

Fenestrated tubes (Figure 2) have an additional opening in the posterior portion above the cuff. This permits upper airway airflow and facilitates speech (St John Malen 2004). These tubes have an additional removable plastic inner cannula and plug. The inner diameters are small compared with their outer diameters, and the fenestrations can obstruct. For a proper fit, the patient's stoma should be measured, and the distance from the flange to the fenestration should be 1cm longer than that of the stoma (Dunn & Goulet 2000). The tube shape is designed to allow correct entry angle into the trachea to facilitate ventilation and clearance of secretions.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Adjustable flange tubes

The length of a flange tube can be adjusted. This is particularly useful in patients with larger necks or increased pretracheal space.

Complications

Intraoperative complications Primary haemorrhage

Bleeding is the most common complication following tracheotomy. Primary bleeding is commonly due to injury to the anterior jugular veins or thyroid isthmus, and most authors therefore recommend suture ligation of the thyroid isthmus. Heffner's description of the subthyroid tracheotomy is also popular as it avoids injury to the thyroid itself (Heffner et al 1986).

Injury to the larynx and trachea

The important sites of damage to avoid are the posterior tracheal wall, cricoid cartilage and 1st tracheal ring. Injury to the posterior tracheal wall may result in a tracheooesophageal fistula. Dissection lateral to the trachea should be avoided as this risks inadvertent injury to the recurrent laryngeal nerves or carotid sheath.

Air embolism

Air embolism is a rare complication and occurs if the internal jugular vein is injured. Injury can be avoided by dissecting in the midline.

Early postoperative complications Tube obstruction

Inadequate suctioning or failure of humidification of inspired air results in viscid secretions that block the tube and compromise ventilation. In such a situation, the inner tube should be removed and inspected for crusting. Further examination can be assisted with the help of a flexible nasendoscope passed through the lumen of the tube to assess the lower airway. Airway crusts should be managed with nebulised saline or 5mls of saline trickled down the trachea to soften the crusts and aid suction clearance.

Wound infection

True infection is rare and therefore antibiotics are not routinely prescribed. Infection may lead to tracheitis, perichondritis and/or tracheal stenosis.

[FIGURE 3 OMITTED]

Subcutaneous emphysema

Subcutaneous emphysema can occur secondary to wound closure under tension, false tube passage or excessive positive pressure ventilation. Emphysema may progress on to pneumothorax or pneumomediastinum.

Tube displacement

Tube displacement within the first 48 hours is an airway emergency as the tract is not formed. Orotracheal intubation should be performed immediately to establish satisfactory airway.

Late complications

Granuloma formation/tracheal stenosis

This is a foreign body reaction secondary to ill fitting tubes. They commonly occur at the stoma but may also occur in the lumen. Stomal granulation tissue frequently develops, and nearly all patients have some degree of tracheal narrowing at the site of the tracheostoma. In contrast, only 3-12% of these patients demonstrate clinically important stenosis that ultimately requires intervention (Epstein 2005). Treatment involves correct sizing of tubes, cautery of granulation tissue and/or laser ablation.

Tracheo-oesophageal fistula

Formation of a tracheo-oesophageal fistual is relatively rare, occurring in less than 1% of cases (Epstein 2005). Intraoperative injury to the posterior tracheal wall or pressure necrosis secondary to an overinflated cuff can result in a tracheooesophageal fistula. Nasogastric feeding is also associated with an increased risk of trachea-oesophageal fistula.

Tracheo-cutaneous fistula

Prolonged tube placement may result in complete epithelialisation of the tract and failure to close after decannulation. This can be managed by freshening the edges of the stoma and allow healing by secondary intention. Occasionally the fistula may have to be excised and closed in layers.

Tracheo-innominate artery fistula

According to Scott and Epstein (2005) and Ridley and Zwischenberger (2006), tracheainnominate artery fistula occurs in less than 1% of cases. Most fistulas result from direct pressure of the cannula against the innominate artery. Risk factors include low placement of tracheotomy, and high pressure cuffs. The mortality rate approaches 100%, even when surgical intervention is undertaken (Scott & Epstein 2005).

Decannulation

Decannulation should be considered only when the patient is clinically stable and able to expectorate. The most reliable indicator of decannulation is when there is no further need for airway protection or mechanical ventilation. Airflow should be adequate through the tube which is achieved with both uncuffed and fenestrated tubes. The tube is initially blocked during the day and released at night. This is followed by blockage for a continuous period of 24 hours. Once tolerated, the patient can be safely decannulated. Decannulation is challenging in patients who have had the tube in position for a longer period of time. In these patients the procedure is staged over a few days. Following decannulation, the stoma is covered with a sterile dressing. Spontaneous wound closure usually occurs within 7 to 10 days.

Conclusion

The increasing use of tracheostomy emphasises on the importance of comprehensive knowledge for modern surgeons as well as those physicians involved in the creation of and care for tracheostomies. Even though the procedure is associated with many dreadful complications, most of them can be avoided with a meticulous surgical approach and dedicated postoperative care administered by a multidisciplinary team.

No competing interests declared

Provenance and Peer review: Unsolicited contribution; Peer reviewed; Accepted for publication February 2011.

References

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Correspondence address: Vamsidhar Vallamkondu, ENT/Head and Neck Surgery, Monklands Hospital, Glasgow, ML6 0JS. Email: vams21@doctors.org.uk

by Vamsidhar Vallamkondu and Vikranth Visvanathan

About the authors

Vamsidhar Vallamkondu

MBBS, MS

Locum Appointed Trainee, Monklands Hospital, Glasgow

Vikranth Visvanathan

MRCS, DOHNS

Specialist Trainee, The Royal Hospital for Sick Children, Glasgow
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