A 28-year-old, previously healthy female 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 fractured 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 a pH 7.47, PCO2 37 mm Hg, PO2 60 mm Hg, and HCO3 26 mEq·L−1. Her respiratory rate is 20 breaths per minute. All other vital signs are stable. You have been consulted to help perform a tracheotomy.
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 hopes of minimizing long-term airway complications,3 but standard practice dictates a range of 7 to 10 days following the initial intubation. While a Cochrane review4 showed lower mortality in an early tracheotomy group (<10 days) and a higher propensity for discharge from the ICU at day 28, a meta-analysis found no difference in mortality, length of ICU stay, or risk of ventilator-acquired pneumonia when compared to the late tracheotomy group (>10 days) but did find that the duration of sedation was decreased.5 Notwithstanding, in a retrospective study of early versus late tracheotomy in trauma patients, Hyde et al.6 showed a significantly lower length of ICU stay, ventilator-acquired pneumonia, and ventilator days in the early group. However, in this study early tracheotomy was shorter than the previous analyses, <5 days. Thus, if prolonged intubation is predicted based on patient circumstances such as trauma, for example, a high spinal cord injury, then earlier conversion to tracheotomy may be considered.
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,3,7 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.8,9
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 alter 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 temporo-mandibular joints and mandible, reconstructive orthognathic or cosmetic surgery, fusion of the cervical spine, or patients with severe burns to the head and neck.10,11 For example, Coonan et al.12 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.
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.
Surgical access to the trachea through the anterior neck requires knowledge and recognition of surface anatomy landmarks of the larynx as well as the important adjacent structures in the neck. Equally important, dexterity and familiarity with flexible bronchoscopy is essential as a guide to safely complete a PDT.
Easily palpable landmarks include: the hyoid bone, situated high in the neck just below the submental space and having a primary suspensory role for the airway; the thyroid notch, most prominent in adult males and identifying the superior aspect of the thyroid cartilage; the cricoid cartilage, the only complete ring, and bridged by the cricothyroid membrane to the inferior portion of the thyroid cartilage (Figure 33–1). 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 postero-superior 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 within the trachea will ensure proper positioning of the tracheostomy tube.
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 in the adult patient because the cricothyroid membrane is superficial, easily identifiable, and thus easiest to access (see Chapter 14).3 Controversy has existed about the long-term use of cricothyrotomy due to early reports of subglottic stenosis (SGS), limiting its use to emergency airway access.13 However, reexploration of this notion in a prospective study involving 118 patients has shown the incidence and severity of complications to be similar between traditional tracheotomy and cricothyrotomy techniques.13 A review of the literature from 1978 to 2008 identified 20 published series in which emergency cricothyrotomy was performed with an overall SGS rate of 2.2%.14 The same authors identified only two studies examining the complications associated with converting a cricothyrotomy to tracheotomy and reported it as 53%. Contrary to standard ASA difficult airway algorithm and Advanced Trauma Life Support teaching, at least one center uses ST for emergency airway management more often than cricothyrotomy.15
The first modern-day ST performed by Chevalier Jackson in the early 1900s involved entering the trachea at the second or third tracheal rings.16 He advocated avoiding the first and second tracheal rings due to a high incidence of subsequent SGS.17 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 SGS whereas placement too low may predispose to erosion of the anterior tracheal wall and possible creation of a tracheoinnominate fistula.18
The first percutaneous tracheotomy not requiring neck dissection was described in 1955 by Shelden,19 during which a slotted needle was introduced blindly into the tracheal lumen. Subsequently, several deaths were reported secondary to laceration of vital structures in proximity to the airway.20 Toye and Weinstein21 performed the first tracheotomy using a Seldinger technique where a single tapered dilator was introduced with a recessed cutting blade. In 1985, Ciaglia et al.22 introduced a dilational Seldinger technique which has since been refined and has now become one of the most popular techniques for PDT.23 Initially, PDT was performed in the immediate subcricoid space,22 but in a follow-up publication, the space between the first and second tracheal rings was advocated.24 But, the more distal approach (beyond the second ring) was not recommended due to the risk of bleeding from the thyroid isthmus24 or from puncture of an aberrant, high-riding innominate artery.
Describe the Different Techniques Used to Perform an Elective Surgical Airway (For Techniques to Manage an Emergency Surgical Airway, Refer to Chapter 14)
Surgical Tracheotomy (Please See Chapter 15 for Details of the Technique)
ST is usually performed under general anesthesia in the operating room. The neck is extended to elevate the trachea into the neck. 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.18 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 confirming 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.18
Percutaneous Dilational Tracheotomy
The PDT technique is easily performed at the bedside with two practitioners: 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.25 Pharmacologic muscle relaxation during needle insertion is desirable to help prevent inadvertent puncture of the posterior tracheal wall or coughing during the insertion of the tracheotomy tube. For continued mechanical ventilation during the procedure, after ETT cuff deflation, adjustments are made to tidal volume, respiratory rate, and PEEP 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 1989.26 Bronchoscopy allows visualization of the needle entering the trachea, helping to confirm its location in the midline at the correct tracheal interspace, ensuring that the ETT is not punctured or impaled, and also minimizing the risk of damaging the posterior tracheal wall.23 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.20 The disadvantages of flexible bronchoscopy include difficulties with ventilation and oxygenation leading to hypercarbia and hypoxemia23 and the potential for damage to the bronchoscope by the needle or guidewire.
Other 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 by identifying the appropriate level as well as structures at risk of hemorrhage, such as variant innominate artery anatomy.27 Kollig et al.28 used ultrasound to determine the site of puncture followed by confirmatory bronchoscopy; ultrasound findings changed the tracheal puncture site in 24% of the procedures, primarily due to identification of subcutaneous blood vessels. A retrospective observational study comparing 95 ultrasound-guided PDTs with bronchoscopic confirmation to 82 cases without subsequent bronchoscopic confirmation resulted in a significantly longer procedure time (13.9 vs. 10.7 minutes) and more oxygen desaturation to <90% (16.8% vs. 3.7%) in the bronchoscopic group.29 Bronchoscopy was used in three patients originally enrolled in the ultrasound-only group, one patient of which was found to have the wire directed cranially. Although ultrasound offers many advantages, a prospective randomized control trial is needed.30 Capnography has been used to confirm tracheal needle placement and has been shown to be equally effective as bronchoscopy.31 Portable monitors are now available to quantify CO2 at the bedside.
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 pre-measured blind withdrawal.23 In 2000, our group described a technique using a lightwand (Trachlight™ [Laerdal Medical Inc., Wappingers Fall, NY]), a common and inexpensive intubation device, as an alternative to bronchoscopy to facilitate the PDT. The lightwand device can be advanced into the ETT. In order to place the lightbulb of the lightwand at the tip of the ETT, the number markings on the lightwand shaft must be lined up with those on the ETT. Anterior neck transillumination32 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, beveled dilator instead of multiple dilators.23 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 below in more detail.
Under optimal conditions, the neck is extended and the surgical field is aseptically prepared (Figure 33–2A). 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 subcutaneously. A vertical skin incision is made in the midline from the level of the cricoid cartilage caudally 1 to 1.5 cm (Figure 33–2B). 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 (e.g., 2–3 mL of lidocaine) (Figure 33–2C). 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 of the introducer needle 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 guidewire is advanced through the sheath into the trachea (Figure 33–2D). The sheath is then removed. Although not specified by the manufacturer, in our experience, it is beneficial to make a second cut around the guidewire with the scalpel to provide room for the dilator. A short 14 French introducing mini-dilator is advanced over the guidewire 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 33–2E). 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 (Figures 33–2F and 33–2G). The guide wire and dilator are then removed leaving the tracheostomy tube in situ (Figure 33–2H). The tracheostomy tube cuff is inflated and its proximal connector is attached to the ventilator (Figure 33–2I). Once insertion into the trachea has been confirmed by end-tidal CO2 detection, the translaryngeal ETT is removed.
FIGURE 33–2.
Percutaneous dilational tracheotomy. (A) Monitors are applied and the neck is extended and prepped. (B) The first or second tracheal interspace is identified, and a vertical skin incision is made in the midline from the level of the cricoid cartilage caudally 1 to 1.5 cm. (C) An introducer needle is inserted with a syringe and aspirated until a free flow of air is obtained. (D) A J tipped guidewire is guided into the trachea through the needle. (E) A dilator is advanced over the guidewire. (F, G) The tracheostomy tube is then inserted over the dilator and guide wire, and the tracheostomy tube and dilator are advanced as a unit into the trachea. (H) The dilator is then removed leaving the tracheostomy tube in situ. (I) The cuff of the tracheostomy tube is inflated and connected to the ventilator. (Part F, provided with permission from Cook Critical Care, Bloomington, IN)
Other PDT techniques have been developed.8,23 The Rapitrach kit (Surgitech Medical, Sydney, Australia) uses a dilating tracheotome with blades designed to slide over the guidewire into the trachea. To create a stoma, it is necessary to squeeze the blades opened.33 Unfortunately, the Rapitrach method resulted in a high rate of posterior tracheal wall and balloon cuff tears and was removed from the US market.23 The Griggs technique uses a Howard-Kelly forceps that is introduced into the tracheal lumen with the guidewire.34 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.23 A third method is a translaryngeal approach developed by Fantoni and Ripamonti.35 With this technique, a guide wire is inserted cephalad 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-tracheostomy 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 delivered 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.23 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 internal diameter (ID) tracheostomy tube is fitted with the insertion dilator and subsequently advanced over the guidewire into the trachea.36 The Percutwist™ has had a higher rate of posterior wall puncture than the Ciaglia Blue Rhino technique.37 The newest technique is a modification of the Ciaglia single-dilator technique that involves balloon dilation38 but this was found to require more time and be more difficult to perform when compared to the Ciaglia single-dilator technique.39 Two meta-analyses have been performed to analyze randomized control studies comparing different PDT techniques in patients requiring long-term ventilation. The first meta-analysis concluded that the original Ciaglia multiple-dilator and Ciaglia single-dilator techniques were the best available, followed by the Griggs technique.40 However they concluded the number of available trials was insufficient to definitely conclude which PDT technique was the best. The second meta-analysis concluded that the Ciaglia single-dilator method was less difficult but also that surgeons had more experience with this technique.41
In selecting a tracheostomy tube, patient anatomy and ventilatory needs must be considered. These needs will influence choice of tube ID, length, cuff design, use of an inner cannula, and presence or absence of fenestrations. Sizing usually refers to the ID. The smallest outer diameter that satisfies the requirement for ventilation should be chosen.18 Optimal sizing should aim for a tracheostomy tube approximately three-quarters of the diameter of the tracheal lumen.