Chapter 31. Performing an Elective Percutaneous Dilational Tracheotomy in a Patient on Mechanical Ventilation

A 28-year-old, previously healthy woman was thrown off an all terrain vehicle (ATV) and sustained blunt trauma to her chest. Her injuries included a flail chest with fractures of the right first and second ribs, a pulmonary contusion, as well as a right femur fracture and ruptured spleen. Following a splenectomy on the first night, she stabilized hemodynamically and subsequently underwent an open reduction internal fixation of the femur. On the 10th day, she failed an extubation attempt due to hypoxemia. Currently she is being ventilated with a pressure support of 12 cm H2O, positive end-expiratory pressure (PEEP) of 5 cm H2O, and FiO2 0.50. Her ABG shows pH 7.47, PCO2 37, PO2 60, and HCO3 26 torr. Her respiratory rate is 20 breaths per minute (bpm). All other vital signs are stable. You have been consulted to help perform a tracheotomy.

31.2.1 Why Would You Perform a Tracheotomy on This Patient?

Local changes occur in airway mucosal surfaces following as little as 2 hours of endotracheal intubation. These pathophysiologic changes include a well-documented progression of mucosal ulceration, pressure necrosis, granulation tissue with subsequent healing, fibrosis, and occasionally stenosis.1,2 There exists no consensus on the ideal timing of performing a tracheotomy in the hope of minimizing long-term airway complications,3 but standard practice dictates a range of 7 to 10 days following the initial intubation. Griffiths et al did a meta-analysis of five studies on early (0-7 days) versus late (= 8 days) tracheotomy.4 No difference was shown in mortality and risk of pneumonia. Early tracheotomy decreased length of stay in the intensive care unit (ICU) and length of artificial ventilation. Dunham and Ransom showed no difference in mortality, pneumonia, or ventilator/ICU stay between early versus late tracheotomy except in patients with severe brain injury.5 Thus, if prolonged intubation is predicted based on patient circumstances, such as a high spinal cord injury, then earlier conversion to tracheotomy may be considered.

31.2.2 What Are the Advantages of a Tracheotomy over a Prolonged Translaryngeal Intubation?

The potential advantages of a tracheotomy over a prolonged translaryngeal intubation include less direct endolaryngeal injury, a potentially decreased risk of nosocomial pneumonia in certain patient subgroups,3,6 more effective pulmonary toilet, and possibly decreased airway resistance for promoting weaning from mechanical ventilation. Additional benefits include improved patient comfort, communication and mobility, increased airway security, decreased requirements for sedation, better nutrition, and earlier discharge from ICU.7

31.3.1 If a Tracheotomy Is Going to Be Performed Anyway, Why Is It Important to Know Whether This Patient Has a Difficult Airway or Anatomical Features Associated with Difficult Laryngoscopic Intubation?

In fact, it is extremely important to assess the airway prior to performing a tracheotomy. When performing either a surgical tracheotomy (ST) or a percutaneous dilational tracheotomy (PDT), during the procedure the indwelling endotracheal tube (ETT) must be carefully withdrawn above the tracheotomy site to accommodate insertion of the tracheostomy tube. During this maneuver there is a potential risk of premature extubation and need for controlled ventilation and reintubation. Ultimately, preparing for a successful procedure requires a thorough chart review, patient airway assessment, proper equipment preparation (including the difficult airway cart if the patient has a history of difficult laryngoscopic intubation), and proper patient positioning. Attention to these factors and having qualified, briefed assistants will help minimize the need for emergency airway access should unanticipated difficulty arise.

While the importance of assessment and preparation is well accepted in airway management, the dynamic nature of the upper airway anatomy is often overlooked. Surgical procedures or radiotherapy that alters skeletal or soft tissues of the head and neck can change the upper airway anatomy, making laryngoscopic intubation difficult. A high index of suspicion should be applied to patients who have undergone recent surgery of the temporomandibular joints and mandible, reconstructive orthognathic or cosmetic surgery, fusion of the cervical spine, or patients with severe burns to the head and neck.8,9 For example, Coonan et al10 reported a patient with an unanticipated difficult laryngoscopy secondary to contracture of the temporalis muscle causing ankylosis of the jaw several weeks following a temporal craniotomy. Many patients presenting for tracheotomy will have undergone recent surgery; in evaluating these patients, the potential for such dynamic changes to what may previously have been an easily managed airway should always be considered.

31.3.2 How Would You Assess This Patient's Airway?

The patient's chart should be reviewed to determine if there is a history of difficult laryngoscopic intubation or difficult bag-mask-ventilation. Chapter 1 has reviewed anatomic and physiologic factors which may predict difficulty with each. The neck should also be assessed for C-spine stability and other factors that could create difficult surgical conditions such as cervical flexion deformity, obesity, previous neck surgery or radiation therapy, active neck infection, or tumor.

31.4.1 Describe the Anatomy of the Airway with Respect to Performing a Percutaneous Dilational Tracheotomy

Surgical access to the airway through the trachea requires knowledge and recognition of surface anatomy landmarks of the larynx as well as the important adjacent structures in the neck. Most importantly, dexterity and familiarity with flexible bronchoscopy is essential as a guide to safely complete a PDT.

Easily palpable landmarks in the anterior neck include the following: the hyoid is situated high in the neck, just below the submental space, and provides a primary suspensory role for the airway; the thyroid notch, most prominent in adult males, identifies the superior aspect of the thyroid cartilage; the cricoid cartilage is the only complete ring and is bridged by the cricothyroid membrane to the inferior portion of the thyroid cartilage (Figure 31-1). With the neck extended, palpation inferiorly from the cricoid cartilage may reveal proximal tracheal rings and the thyroid gland. The vocal cords are protected by the body of the thyroid cartilage anteriorly and attach to the arytenoid cartilages which articulate from the posterosuperior margin of the cricoid ring.

An experienced practitioner must perform flexible bronchoscopy to identify the level of important internal laryngeal structures (supraglottis, glottis, and subglottis) and to transilluminate the area between the second to fourth tracheal rings. In patients with poorly palpable surface anatomy, transillumination and visual confirmation of the guide needle will ensure proper positioning of the tracheostomy tube.

31.4.2 Compare and Contrast the Different Sites at Which Surgical Airway Access Can Be Performed

Surgical access to the airway can be gained at the cricothyroid space, subcricoid space, or between any of the tracheal rings. To secure an emergency airway rapidly, a cricothyrotomy is preferable because the cricothyroid membrane is superficial, easily identifiable, and thus easiest to access (see Chapter 13).3 Controversy has existed about the long-term use of cricothyrotomy due to early reports of subglottic stenosis, limiting its use to emergency airway access.11 However, reexploration of this notion in a recent prospective study involving 118 patients has shown the incidence and severity of complications to be similar between traditional tracheotomy and cricothyrotomy techniques.11

The first modern-day surgical tracheotomy (ST) performed by Chevalier Jackson in the early 1900s involved entering the trachea at the second or third tracheal ring.12 He advocated avoiding the first and second tracheal rings due to a high incidence of subsequent subglottic stenosis.13 Current consensus dictates that in ideal circumstances a tracheotomy is performed between tracheal rings two to four. Injury to the first ring or cricoid cartilage may increase the risk of subglottic stenosis, whereas placement too low may predispose to erosion of the anterior tracheal wall and possible creation of a tracheoinnominate fistula.14

The first percutaneous tracheotomy not requiring neck dissection was described in 1955 by Shelden,15 during which a slotted needle was introduced blindly into the tracheal lumen. Several deaths occurred secondary to laceration of vital structures in proximity to the airway.16 Toye and Weinstein17 performed the first tracheotomy using a Seldinger technique where a single, tapered dilator was introduced with a recessed cutting blade. In 1985, Ciaglia18 introduced a dilational Seldinger technique which has since been refined and has now become one of the most popular techniques for PDT.19 Initially, PDT was performed in the immediate subcricoid space,18 but in a follow-up publication the space between the first and second tracheal rings was advocated.20 But, the more distal approach (beyond the second ring) was not recommended due to the risk of bleeding from the thyroid isthmus20 or from puncture of an aberrant, high-riding innominate artery.

31.4.3 Describe the Different Techniques Used to Perform an Elective Surgical Airway (for Techniques to Manage an Emergency Surgical Airway, Refer to Chapter 13)

31.4.3.1 Surgical Tracheotomy

ST is usually performed under general anesthesia in the operating room. The neck is extended to elevate the trachea into the neck (Figure 31-1). Depending on the length of the patient's neck, a horizontal incision is generally made crossing the midline approximately 2 cm above the sternal notch. The subcutaneous tissue and platysma muscle are divided transversely. The remainder of the dissection is performed longitudinally through the superficial cervical fascia and the linea alba dividing the strap muscles. Lateral retraction of the strap muscles often reveals the thyroid isthmus, which is commonly divided to provide better surgical access and to minimize the risk of bleeding by its manipulation.14 Various types of tracheal incisions have been used. Quite frequently a superiorly based Bjork flap or window is made by unroofing the second or third tracheal ring.

To avoid damaging the indwelling ETT cuff during tracheotomy, it is a common practice to deflate the cuff and purposely advance the ETT distally into the right mainstem bronchus prior to making an incision in the trachea. Following tracheal access, the ETT is withdrawn under direct vision to just above the tracheotomy site by the airway practitioner. Superior retraction on the cephalad tracheal ring with a tracheal hook and spreading of the tracheal incision facilitates subsequent insertion of the tracheostomy tube.

Endotracheal positioning is confirmed by connecting the tracheostomy tube to the ventilatory circuit and monitoring for the presence of end-tidal CO2. These final measures, in addition to assessing lung compliance and airway pressures, are ascertained prior to the complete removal of the ETT. The tracheostomy tube is then secured with sutures, and a tie passed around the neck.14

31.4.3.2 Percutaneous Dilational Tracheotomy

The PDT technique is easily performed at the bedside with two operators: one performing the tracheotomy while the second provides ventilation and oxygenation. It is essential to continuously monitor vital signs including pulse oximetry, blood pressure, heart rate, and rhythm. The patient should be ventilated with 100% oxygen throughout the procedure. The patient's current sedative regime can be supplemented with an opioid and an intravenous sedative/hypnotic such as a benzodiazepine or propofol.21 It is important to maintain immobility during insertion of the needle to prevent inadvertent puncture of the posterior tracheal wall or coughing during the insertion of the tracheotomy tube, for example, through the use of a nondepolarizing muscle relaxant, such as rocuronium. For continued mechanical ventilation during the procedure, the cuff of the ETT is deflated and adjustments to tidal volume, respiratory rate, and PEEP are made to compensate for the air leak. At our institution, the patient is manually ventilated with a bag-mask device and 100% oxygen throughout.

Flexible bronchoscopy through the ETT to facilitate PDT insertion was introduced in 1989.22 Bronchoscopy allows visualization of the needle entering the trachea, helping to confirm its location in the midline at the correct tracheal interspace, as well as ensuring that the ETT is not punctured or impaled and minimizing the risk of damaging the posterior tracheal wall.19 In the case of accidental premature extubation, the bronchoscope can also be used to guide ETT reinsertion. There may also be a role for videoscopic bronchoscopy during teaching as there is a learning curve to performing PDT.16 The disadvantages of flexible bronchoscopy include difficulties with ventilation and oxygenation leading to hypercarbia and hypoxia19 and the potential for damage to the bronchoscope by the needle or guidewire.

Adjuncts, such as ultrasound and capnography, are increasingly being used to aid successful PDT. Ultrasound can help to determine the site of tracheal puncture prior to PDT, identifying structures at risk of hemorrhage such as variant arterial anatomy, primarily an aberrant innominate artery.23 Kollig et al used ultrasound to determine the site of puncture followed by bronchoscopy; ultrasound findings changed the tracheal puncture site in 24% of the procedures.24 Portable monitors are now available to quantify CO2 at the bedside. Capnography and bronchoscopy have been shown to be equally effective to confirm tracheal needle placement.25

Prior to tracheal puncture, the ETT must be withdrawn to avoid cuff laceration or ETT impalement. Besides bronchoscopy, alternative methods have been advocated to confirm adequate ETT withdrawal before tracheal puncture. These include use of direct laryngoscopy with a tube exchanger, ETT cuff palpation, and premeasured blind withdrawal.19 In 2000, our group described a technique using the Trachlight™ (Laerdal Medical Inc., Wappingers Fall, NY), a common and inexpensive intubation device, as an alternative to bronchoscopy to facilitate the PDT. With the internal stiff wire removed from the Trachlight™, the pliable lightwand device is advanced into the ETT. In order to place the lightbulb of the Trachlight™ at the tip of the ETT, the number markings on the Trachlight™ wand shaft must be lined up with those on the ETT. Anterior neck transillumination26 can then be used to confirm adequate withdrawal of the ETT prior to the needle puncture.

Since the original report of PDT by Ciaglia, the procedure has undergone three modifications. These include the movement of the tracheal cannulation site to one or two interspaces caudal to the cricoid cartilage; the use of bronchoscopy and the use of a single, bevelled dilator instead of multiple dilators.19 While currently several kits are available for the Ciaglia single dilator technique, only the Ciaglia Blue Rhino™ kit (Cook Critical Care, Bloomington, IN) will be presented.

Under optimal conditions, the neck is extended and the surgical field is aseptically prepared (Figure 31-2A). The tracheostomy tube cuff must be checked for leaks and then well lubricated. The first or second tracheal interspace is located and local anesthetic injected (Figure 31-2B). A vertical skin incision is made in the midline from the level of the cricoid cartilage downward 1 to 1.5 cm. The wound is dissected bluntly to the subcutaneous fascia using a hemostat. The ETT should be withdrawn to 1 cm above the anticipated needle insertion site under bronchoscopic guidance. A 17-gauge sheathed introducer needle is advanced in a midline, posterior, and caudad direction. The tracheal air column is identified when air is aspirated into a fluid-filled syringe (eg, 2-3 mL of lidocaine) (Figure 31-2C). At this time the ETT is advanced and withdrawn 1 cm to verify that the needle does not concomitantly move, to rule out inadvertent impalement of the ETT. The outer sheath is then advanced into the trachea while the introducer needle is removed. The fluid-filled syringe is then reattached to the sheath and its position in the trachea is reconfirmed by free flow of air. To minimize the responses to the subsequent insertion of the dilator, the lidocaine in the syringe is instilled into the trachea. The syringe is removed and a 1.32 mm diameter J-tipped guide wire is advanced through the sheath into the trachea (Figure 31-2D). The sheath is then removed. Although not specified by the manufacturer, in our experience, it is beneficial to make a second cut around the guide wire with the scalpel to provide room for the dilator. A short 14 French introducing mini-dilator is advanced over the guide wire using a slight twisting motion and then removed. The Ciaglia Blue Rhino™ dilator, after soaking in water, is then advanced over the guide wire while maintaining the wire position (Figure 31-2E). The dilator and guide wire are advanced together into the trachea up to the black skin level mark. The dilator is withdrawn and advanced several times to help create the stoma, whereupon it is removed. The lubricated tracheostomy tube with its internal dilator is then inserted over the guide wire and advanced as a unit until it reaches the flange (Figure 31-2F and G). The guide wire and dilator are then removed, leaving the tracheostomy tube in situ (Figure 31-2H). The cuff is inflated and the tracheostomy tube's proximal connector is attached to the ventilator (Figure 31-2I). Once insertion into the trachea has been confirmed by end-tidal CO2 detection, the translaryngeal ETT is removed.

Other PDT techniques have been developed.7,19 The Rapitrach kit (Surgitech Medical, Sydney, Australia) used a dilating tracheotome with blades designed to slide over the guidewire into the trachea. To create a stoma, it was necessary to squeeze the blades open.27 Unfortunately, the Rapitrach method resulted in a high rate of posterior tracheal wall and balloon cuff tears and was removed from the US market.19 The Griggs technique uses a Howard-Kelly forceps that is introduced into the tracheal lumen with the guidewire.28 A stoma is created when the forceps are opened, similar to the Rapitrach method, but without a cutting blade. This technique is popular in South America and Europe.19 A third method is a translaryngeal approach developed by Fantoni and Ripamonti.29 With this technique, a guide wire is inserted retrograde into the tracheal space and pulled out through the mouth. A trocar and tracheostomy tube with a pointed tip is then advanced over the wire and with traction applied to the guidewire, the trochar-tracheotosmy tube assembly is advanced through the mouth into the trachea. A pretracheal incision is then made over the skin so that the trocar end of the tracheostomy tube can be pulled through the anterior neck. The trocar is then cut away leaving the tracheostomy tube in place. This technique avoids the downward direction of dilation and thus may minimize damage to the posterior tracheal wall.19 A fourth method uses a single dilator from the Percutwist™ Tracheostomy Dilator Set (Rüsch, Kernen, Germany). This procedure uses a Seldinger technique in which a hydrophilically coated Percutwist™ dilator is moistened and advanced over a guide wire with a twisting motion to enlarge an opening in the anterior tracheal wall. A 9.0 mm ID tracheostomy tube is fitted with the insertion dilator and subsequently advanced over the guidewire into the trachea.30 The Percutwist™ has had a higher rate of posterior wall puncture than the Ciaglia Blue Rhine technique.31

31.4.4 Describe and Compare Different Tracheostomy Tubes. Which Tube Would You Choose for This Patient?

In selecting a tracheostomy tube, patient anatomy and ventilatory needs must be considered. These needs will influence choice of tube internal diameter, length, cuff design, use of an inner cannula, and presence or absence of fenestrations. Sizing usually refers to the inner diameter (ID). The smallest outer diameter that satisfies the requirement for ventilation should be chosen.14 Optimal sizing should aim for a tracheostomy tube approximately three-quarters of the diameter of the tracheal lumen.

In our case presentation, the indication for tracheotomy is prolonged intubation and ventilation, so a cuffed tube which seals the airway and prevents loss of tidal volume would be a good selection. One example of such a cannula is the No. 6 (6.0 mm ID) Shiley (Mallinckrodt, St. Louis, MO) with a large-volume, low-pressure, air-filled cuff14 (Figure 31-3B). It is important to maintain an inflated cuff pressure of less than 30 cm H2O to prevent tracheal mucosal ischemia and minimize the risk of erosion. Once the patient is weaned from the ventilator, conversion to a fenestrated tube (Figure 31-3C) might be appropriate because it reduces resistance to flow of air through the lumen of the tube, enabling vocalization.14 Another option is to downsize the nonfenestrated tracheostomy tube which would also permit the patient to vocalize, while minimizing the risk of granulation tissue formation at the site of the fenestration. Excessive granulation tissue can cause tracheostomy tube obstruction and may also produce impressive bleeding from the airway. But, in general, the choice of a tracheostomy tube is often based on the practitioner's individual experience and preference.

Special consideration must be given to the obese patient. Standard tracheostomy tubes are unlikely to conform to the anatomy and thus a better choice is a flexible tube which is extra long and adjustable,14 such as Bivona (Bivona Medical Technologies, Gary, IN) or Tracoe (TRACOE Medical GmbH, Frankfurt, Germany) tracheostomy tubes. The disadvantage of these tubes is that they have a single lumen without an inner cannula. They do have an advantage of minimizing risks of an inappropriately fitted tube, such as tube obstruction if too short, or necrosis of the anterior tracheal wall if too long.

31.4.5 What Are the Advantages of Performing Percutaneous Dilational Tracheotomy over Surgical Tracheotomy?

In general, the complications of PDT are few and are comparable to ST.32 Theoretical advantages of PDT include a smaller skin incision, less dissection, and tissue trauma which may lead to less hemorrhage, fewer infections, fewer tracheal problems, and fewer cosmetic deformities. In addition, the procedure can be performed at the bedside in the ICU, by nonsurgical personnel, decreasing the risk of patient transport to the operating room with less overall cost and less use of human resources.13,20,33 The disadvantages of performing PDT in the ICU relate mainly to lack of proper facilities and equipment. Poor lighting conditions and a crowded environment can also be hazardous. These risks can be minimized by proper preparation of a surgical set that includes drapes, tracheostomy tubes of various sizes, portable electrocautery, and a surgical lamp. A difficult airway cart should also be immediately available with appropriate anesthetic drugs, including muscle relaxants.

31.5.1 What Are the Contraindications to Performing a Percutaneous Dilational Tracheotomy?

Physiologic contraindications to PDT include a patient who is hemodynamically unstable, requires an FiO2 greater than 0.60, PEEP greater than 10 cm H2O6, or has an uncontrolled coagulopathy.3 Anatomic contraindications include a previously documented difficult tracheal intubation, morbid obesity, obscure cervical anatomy, goiter, short thick neck, previous tracheotomy or neck surgery, cervical infection, facial and cervical trauma and fractures, halo traction, or known presence of subglottic stenosis.3,6 However, PDT has been successfully performed in the morbidly obese and in those who had a previous tracheotomy.34

31.5.2 What Are the Complications of Percutaneous Dilational versus Surgical Tracheotomy?

Complications common to both percutaneous dilational tracheotomy (PDT) and surgical tracheotomy (ST) are listed in Table 31-1 and are summarized in a recent review by Engels et al.35

Three recent meta-analyses have been published comparing PDT to ST. Delaney et al identified 17 randomized trials with 1212 patients and concluded that PDT resulted in significantly fewer infections compared to ST.36 In a pooled data analysis with 973 patients from 15 randomized control trials, Higgins and Punthakee also found that PDT had fewer wound infections, as well as less scarring and lower costs than ST. This difference was lost when only bedside procedures were considered. PDT did result in more decannulation and obstruction problems than ST.37 Oliver et al analyzed 14 prospective and randomized controlled studies with 1273 patients and showed more early, minor complications with PDT than with bedside ST, but no difference in late complications.38

31.6.1 What Should Be Done Immediately after the Placement of a PDT?

Following insertion of the tracheostomy tube, one must ensure that the tube is properly positioned and well secured until the tract has healed, in approximately 7 days. Because PDT is a dilational technique, creation of a false passage may easily occur. Should accidental decannulation occur within the first 7 days of PDT, and if a tracheal tube is needed, an oral ETT should be immediately placed instead of attempting reinsertion of a tracheostomy tube through the stoma.39 Chest x-ray following the procedure is somewhat controversial; studies have shown that the incidence of pneumothorax following endoscopically guided PDT is less than 3%, although when nonguided, it may range up to 12%.40 However, because no strong prospective data exist at this time, recommendations to exclude a routine chest x-ray cannot be made.

31.6.2 Discuss the Special Care of a Tracheostomy Tube

Surgical cannulation of the trachea will cause an increase in secretion production requiring frequent suctioning.39 The suction catheter should be measured such that suctioning beyond the tip of the tracheostomy tube is not performed. If this simple measure is followed, then subsequent risks of deep suctioning will be eliminated. The potential trauma from deep suctioning includes tracheal excoriation, bleeding, ulceration and tracheitis, production of granulation tissue, and scarring of the bronchi and carina.

Creation of a tracheotomy bypasses the nose, so supplemental humidity and filtering of the air must be provided.39 Humidity, in conjunction with tracheal irrigation, will help prevent encrusting of tracheal secretions and minimize mucus plugging of the tracheostomy tube. A filter may be placed on the tracheostomy tube to remove particulate matter in the air and from the ventilator.

The first tracheostomy tube change should be done once the tract is sufficiently mature to minimize the risk of creating a false passage. Although the timing varies with each center, it is generally done 5 to 7 days after an ST.41 However, in our institution, the first tracheostomy tube change is done as early as 3 days. The first change after a PDT is usually at 7 days as the initial stoma is smaller and only created by a puncture.

31.7.1 Should Percutaneous Dilational Tracheotomy Be Performed in the Pediatric Population?

Traditionally PDT is not recommended for individuals younger than 16 years of age, the main drawbacks being the small airway diameter and the pronounced pliability of the cartilaginous framework. Fantoni and Ripamonti42 have tried three different techniques in the pediatric population, one of which consisted of PDT guided by rigid bronchoscopy. This eliminated the main cartilaginous compliance issue seen in the pediatric population and elevated the trachea to a more superficial position, enabling cannulation. Ultimately, any technique used in the pediatric population should be performed in the operating room with specialized surgical staff and anesthesia support. Although the percutaneous dilational technique is still considered experimental in the pediatric patient population, in experienced hands and with the use of a rigid bronchoscope, an overall reduction in complications has been noted. These include smaller operative incisions in the skin and trachea, less blood loss, and virtual elimination of pleural dome injury and posterior wall trauma.42

31.7.2 Can You Perform a PDT in a Patient with Subglottic Stenosis?

Subglottic stenosis (SGS) is a known late complication of prolonged intubation or any type of tracheotomy. However, little has been published on the use of PDT in a patient with SGS. SGS is a graded problem, ranging from mild asymptomatic stenosis to complete obstruction. If the stenosis exceeds 50% to 75% of the lumen diameter, then the patient may be quite symptomatic, possibly requiring acute airway intervention. In known cases of SGS, optimal airway control may be achieved with an extra long, small, noncuffed pediatric ETT, or more likely a controlled tracheotomy performed on an awake patient or over a rigid bronchoscope.

It would be most imprudent to undertake PDT in the face of SGS as the vertical length, or thickness, of the stenosis may not be known even if the diameter is not significantly narrowed. To maximize patient safety and minimize otherwise preventable complications from PDT, this technique should not be used in a patient with known SGS.

31.7.3 What Is the Role of an Extraglottic Device in Providing Oxygenation and Ventilation While Performing the PDT?

To avoid the potential problem of an inadvertent puncture of the ETT cuff by the needle, tube transfixion, or accidental extubation, some reports suggest replacing the in situ ETT with an extraglottic device (EGD) shortly prior to the placement of the PDT. The laryngeal mask airway (LMA), intubating LMA™, LMA-ProSeal™, CobraPLA™, Airway Management device (AMD™), and the Combitube™ have all been used successfully during PDT placement during the last decade.43-49

While EGDs may have a theoretical advantage over the ETT in ventilating critically ill patients during PDT, they also have limitations, including difficult placement. In a prospective comparative study of PDT performed on patients with either an ETT or an LMA in situ, Ambesh et al showed that 33% of patients with LMAs during the PDT suffered potentially catastrophic complications.50 These included loss of the airway, inadequate ventilation with hypoxemia, gastric distension, and regurgitation. In contrast, there were substantially fewer complications in the ETT group.

Until more clinical efficacy and safety data are available on the use of EGDs during PDT, in our opinion, the in situ ETT remains the best option during the procedure. In these critically ill patients who may have low lung compliance, airway edema, cervical spine instability, or a difficult airway, the ETT will provide a more secure airway during PDT. However, in the event that the airway is lost or accidental extubation occurs, EGDs may play an important role in oxygenating the patient while completing the PDT.

To minimize airway complications, tracheotomy is often necessary for long-term mechanically ventilated patients in the intensive care setting. During the last two decades, elective percutaneous dilational tracheotomy (PDT) has been shown to be an effective and safe alternative to traditional surgical tracheotomy. Theoretical advantages of PDT over surgical tracheotomy include a smaller skin incision, less dissection, less tissue trauma, less hemorrhage, fewer infections, fewer tracheal problems, and less cosmetic deformity. In addition, the procedure can be performed at the bedside by nonsurgical personnel, decreasing the inherent risks of transporting patients to the operating room. However, practitioners should also be aware of the limitations and disadvantages of performing PDT in the intensive care unit. These include a lack of proper facilities and equipment, poor lighting conditions, and a crowded environment.