TRACHEOSTOMY. 28 August J Reddy CONTENTS

Transcription

1 28 August 2009 CONTENTS TRACHEOSTOMY J Reddy Commentator: L Pillay Moderator: D Muckart INTRODUCTION... 3 HISTORY OF TRACHEOSTOMY... 3 ANATOMY... 3 PHYSIOLOGY... 6 INDICATIONS FOR TRACHEOSTOMY... 9 CONTRAINDICATIONS BENEFICIAL EFFECTS OF TRACHEOSTOMY TECHNIQUES Open (Surgical) Tracheostomy Percutaneous Tracheostomy Use of Adjuncts Preoperative Ultrasound Bronchoscopy LMA Capnography COMPLICATIONS OF TRACHEOSTOMY Early Complications Late Complications Complications more common with Percutaneous Dilational Tracheostomy Complications more common with Surgical Tracheostomy DECANNULATION PERCUTANEOUS VERSUS SURGICAL TRACHEOSTOMY EMERGENCY TRACHEOSTOMY TIMING OF TRACHEOSTOMY INTERNATIONAL PRACTICE CONCLUSION REFERENCES Department of Anaesthetics Page 2 of 35

2 TRACHEOSTOMY INTRODUCTION Advances and improvements in treating critically ill patients have resulted in more patients requiring prolonged airway and respiratory support. 1 Despite the advances of non-invasive mechanical ventilation, most patients with respiratory failure will require intubation and the question of whether, when and how to perform tracheostomy will need to be addressed. Tracheostomy is one of the most common procedures performed in the intensive care unit. Indications, risks, benefits, timing and technique of the procedure, however, remain controversial. Deciding when and how to perform a tracheostomy is often subjective. The reason for this dilemma is the lack of adequately sized, randomized, prospective controlled studies. Therefore, most recommendations are based on consensus opinions of clinical experts. 1 HISTORY OF TRACHEOSTOMY Tracheostomy is one of the oldest known surgical procedures. The first reference to this procedure is in the ancient Indian book of medicine, the Rig-Veda, written in 1500 BC. 2 Chevalier Jackson is credited with describing the modern-day tracheostomy in Percutaneous tracheostomy was introduced in the mid-1980s as an alternative to surgical tracheostomy and has gained widespread acceptance over the past two decades. ANATOMY It is important to know the anatomy of the neck and the trachea to understand the various approaches to establishing a tracheostomy. Figure 1 Antero-lateral view of larynx3 The lower respiratory tract starts at the vocal cords. Inferior to the vocal cords, the rigid cricoid cartilage encases a cm region known as the subglottic space. Access to this space is possible via the cricothyroid ligament, a membrane that runs from the thyroid cartilage inferiorly to the cricoid cartilage. Inferior to cricoid is the trachea, a cylindrical tube that extends inferiorly and slightly posteriorly. The trachea is made up of C-shaped rings consisting of rigid cartilage anteriorly and laterally, and a membranous posterior portion. In the average adult, the distance from cricoid to carina is approximately 11 cm in length, with a range of cm. On average, the trachea is 2.3 cm in width and 1.8 cm from posterior membrane to the anterior cartilaginous aspect. The trachea is wider in men than in women. 3 Page 3 of 35 Page 4 of 35

3 PHYSIOLOGY As with an endotracheal tube, many changes in airway physiology occur with insertion of a tracheostomy tube. Bypassing the nasal airway, these artificial airways disturb the normal humidification and warming of inspired air. These tubes also affect swallowing. 3 Tracheostomy, compared to translaryngeal endotracheal intubation, may have many physiologic benefits. One of the most important benefits is the potential to improve the chances of liberation from mechanical ventilation. Failure to wean often results from an imbalance between respiratory muscle capacity and the work of breathing. In patients with substantial underlying lung disease, a slight reduction in the work of breathing with a tracheostomy can be beneficial. Figure 2: Anatomy of anterior neck 4 The trachea is protected by strap muscles (sternohyoid, sternothyroid, sternocleidomastoid) and bony structures (manubrium and sternum). The trachea is positioned posterior to a number of blood vessels and the thyroid isthmus. Branches of the bronchial, inferior thyroid, innominate, and subclavian arteries provide the blood supply to the trachea. According to the Poiseuille equation, airflow resistance is directly proportional to the length of a tube and inversely proportional to the radius raised to the 4 th power (when flow is laminar). Turbulent flow occurs when flow rates are high, when secretions adhere to the inside of the tube and because of tube curvature. When compared to the ETT, the tracheostomy tube has the potential to decrease the resistive work of breathing. Tracheostomy tubes are shorter, more rigid, less likely to be deformed in the upper airway and are easier to keep clean. By decreasing resistance, expiratory flow can be enhanced, and the tendency to dynamic hyperinflation and the development of intrinsic positive endexpiratory pressure (PEEP) is reduced. Therefore, when compared to endotracheal tubes, tracheostomy tubes have the potential to also reduce the elastic work of breathing. There have been physiologic studies comparing tracheostomies and endotracheal tubes in mechanically ventilated patients. The most recent and methodological robust studies indicate that these tracheostomy tubes reduce resistive and elastic work of breathing when compared to endotracheal tubes. This is a result of tracheostomy tubes lessening inspiratory and expiratory airways resistance and intrinsic PEEP. Figure 3: Strap muscles of the neck 3 Page 5 of 35 Page 6 of 35

4 Diehl et al studied 8 medical ICU patients 24 hours prior to and 6 hours after surgical tracheostomy, at three different ventilator settings. 5 The inner diameter of the removed endotracheal tube was identical to diameter of the inner cannula of the tracheostomy tube. Tracheostomy was associated with trends in reductions in tidal volume, respiratory rate, and minute ventilation. At all pressure-support levels, tracheostomy was associated with a decrease in the airway occlusion pressure, a measure of respiratory drive. Moreover, reductions in both resistive work of breathing and elastic work of breathing, as indicated by a reduction in intrinsic PEEP, occurred with placement of the tracheostomy. Individual values for PEEPi at baseline pressure support (PS-B) before and after tracheotomy (T). The difference was significant at p Figure 6 5 Individual values for WOB, expressed in J/L, at baseline pressure support (PS-B) before and after tracheotomy (T). The difference was significant at p Davis et al studied 20 surgical ICU patients with acute lung injury. 6 Physiologic measurements were made 6 8 hours before and hours after placement of a surgical tracheostomy. Tracheostomy was associated with trends in reduction in pressure-time product and expiratory airways resistance. As in the study by Diehl et al, intrinsic PEEP and the work of breathing decreased after tracheostomy. Assuming equivalent inner diameter, reductions in resistive work of breathing most likely result from the reduction in tube length in going from ETT to tracheostomy tube. Figure 4 5 Individual values for P0.1 (occlusion pressure) at baseline pressure support (PS-B) before and after tracheotomy (T). The difference was significant at p Figure 5 5 Page 7 of 35 Table 1 6 Page 8 of 35

5 CONTRAINDICATIONS 1 Absolute Soft tissue infections of the neck Anatomic aberrations Previous major neck surgery Relative Severe respiratory distress with refractory hypoxaemia and hypercapnia Haematologic and coagulation disorders BENEFICIAL EFFECTS OF TRACHEOSTOMY 1 Table 2 6 INDICATIONS FOR TRACHEOSTOMY The main indications for tracheostomy are: Prolonged mechanical ventilation Weaning failure Upper airway obstruction Copious secretions Difficult airway 4 Expected prolonged mechanical ventilation is one of the major indications for tracheostomy. In 1989, the American College of Chest Physicians (ACCP) Consensus Conference on Artificial Airways in Patients Receiving Mechanical Ventilation issued the statement that tracheostomy is preferred over translaryngeal intubation if the need intubation is expected to be greater than 21 days. A similar recommendation followed the European consensus in For mechanical ventilation that was anticipated to last between 10 and 21 days, the decision was left to the attending physician, and daily assessment was recommended as to the need for continued intubation. Recent ACCP guidelines suggest that tracheostomy should be considered after an initial period of stabilization on the ventilator (generally, within 3 7 days), when it becomes apparent that the patient will require prolonged ventilation. 1 Page 9 of 35 The proposed beneficial effects of tracheostomy include: Improved patient comfort Allowance of speech Oral nutrition Easier nursing care The need for less sedation and analgesia requirements Reduced airway resistance Reduction in ventilator-associated pneumonia TECHNIQUES Numerous studies on different techniques of tracheostomy have been published. Alternative techniques to the traditional surgical procedure were attempted as early as 1955, but abandoned because of a high complication rate. Percutaneous dilatational tracheostomy (PDT) was reintroduced with Ciaglia s technique in 1985, and became increasingly popular in the 1990s. 1 Tracheostomy can be performed with the open technique in theatre, with the open technique at the bedside, or with the percutaneous approach at the bedside. Open (Surgical) Tracheostomy In the open technique, a small transverse incision is made between the lower border of the cricoid cartilage and the suprasternal notch. The strap muscles are retracted laterally to expose the underlying thyroid gland and Page 10 of 35

6 the trachea. The thyroid isthmus is retracted in a cephalad direction or divided, exposing the tracheal rings. An incision is made in the tracheal rings. The type of tracheal incision varies at different institutions. 2 A transverse incision can be made between tracheal rings 2 and 3. The third tracheal ring is divided and hinged via connective tissue to the fourth tracheal ring. The flap is sutured to the skin, thereby creating a clear path from the skin to the trachea. This cartilage flap, sutured to the skin, is a Bjork flap. The Bjork flap is preferred by some because it creates a safe track if accidental decannulation occurs. The tracheostomy tube is then placed under direct visualization. 2 After placement of a surgical tracheostomy the fistula tract is not stable for at least 4-5 days and a tube dislodged soon after placement often cannot be reinserted through the fistula into the trachea. The ring sutures may help if this situation occurs. Percutaneous Tracheostomy Various types of percutaneous dilational techniques are available. They all require puncture of the trachea and insertion of a guide wire into the trachea (Seldinger technique). The puncture should be performed between the first and second or between the second and third tracheal rings. At present, six tracheostomy techniques are in frequent use. The methodology, year of introduction, and principles of use are listed in the table below. 8 Techniques Currently Used for Percutaneous Tracheostomy 8 Methodology Year Technique Sequential dilators, Ciaglia 1985 Multistep dilation with sequential dilators, ante grade Figure 7: Bjork Flap 7 Dilating forceps, Griggs 1990 Dilation with specific forceps, ante grade An alternate incision is a longitudinal one. The 2nd tracheal ring is divided laterally and the anterior portion removed. Lateral sutures are used to provide counter traction during tracheostomy tube insertion. These are left uncut to provide assistance should the tube be accidentally dislodged later. Translaryngeal tracheostomy, Fantoni Single-step dilator, Ciaglia Blue Rhino 1997 Retrograde passage; specific cannula acts as dilator and tracheostomy tube 1999 Single-step dilation with a curved dilator and loading dilator, ante grade Dilating screw, Frova/Quintel 2002 Self-trapping screw, ante grade T-Dagger, Ambesh 2005 Single-step dilation with a curved, T- shaped dilator, elliptical in cross section, ante grade Balloon-facilitated dilational tracheostomy, Ciaglia Blue Dolphin 2005 Single-step dilation with balloon and loading dilator assembly, ante grade Figure 8: 2 nd Tracheal ring divided laterally 7 Table 3: Techniques for percutaneous tracheostomy 8 Page 11 of 35 Page 12 of 35

7 Several studies have compared the various methods of percutaneous tracheostomy but no clear advantage has been demonstrated between methods. The modification of the Ciaglia method 9, the Blue Rhino, has become one of the most widely used. This method will be briefly described. The steps for the Ciaglia Blue Rhino are as follows 10 : Ensure patient is appropriately sedated, monitored and positioned Make a 1 cm transverse skin incision 1 cm above clavicular heads Withdraw tip of endotracheal tube into larynx Midline needle puncture of trachea between first and second or second and third tracheal rings (bevel angled caudally) Feed guide wire through needle into distal trachea (Seldinger technique) Puncture trachea with small dilator (14Fr) over guide wire Dilate tracheostoma with tapered dilator to 38Fr Place tracheostomy tube in stoma and secure in place with tapes provided Figure 11: Tapered single step dilator 11 Figure 9: Insertion of guide wire 11 Figure 12: Tracheostomy tube over dilator 4 Figure 10: Dilator over guide wire 11 Page 13 of 35 Figure 13: Tracheostomy tube in place 11 Page 14 of 35

8 Use of Adjuncts 12 Preoperative Ultrasound Ultrasound of the neck may identify structures at risk for haemorrhage, such as aberrant blood vessels. Randomized clinical trials are required before evidence-based recommendations for routine ultrasound before percutaneous tracheostomy may be made. Bronchoscopy Bronchoscopy may provide certain benefits, such as confirmation of needle placement, dilatation and tube placement. No study has yet examined whether the addition of bronchoscopy leads to a decrease in procedural complications. On the other hand, several reports on the use of bronchoscopy raised concern about potential unwanted side effects. Measurable increases in intracranial pressure may be noted with bronchoscopic guidance due to increase in partial carbon dioxide tension. In susceptible individuals partial oxygen tension may decrease, leading to derecruitment. Johnson et al and Maddali et al found no significant differences in terms of major complications between the use of bronchoscopy or not. Paran et al found that a modified percutaneous tracheostomy (in which the subcutaneous tissue is bluntly dissected using a haemostat down to the pretracheal fascia), without routine bronchoscopy, is simple and safe. LMA As an alternative to ETT, the laryngeal mask airway (LMA) has been used. Ambesh et al compared the LMA to the ETT. Potentially catastrophic complications (e.g. loss of airway, inadequate ventilation of lungs leading to significant hypoxia, gastric distension and regurgitation) occurred in 33% of patients in the LMA group, rendering some patients at considerable risk for hypoxia and gastric regurgitation/aspiration. In the ETT group cuff puncture occurred in 6.6% and accidental tracheal extubation in 3.3%, making the ETT technique basically safe. Dosemeci and coworkers evaluated the safety and efficiency of the use of LMA during percutaneous tracheostomy under bronchoscopic guidance Page 15 of 35 compared with ventilation via ETT. Those investigators concluded that, because of better visualization of the trachea and larynx during fibreoptically assisted percutaneous tracheostomy, LMA could represent an effective and valuable ventilatory device during percutaneous tracheostomy. It prevents the difficulties associated with the use of ETTs, such as cuff puncture, tube transection by the needle and accidental extubation. It is believed that the applicability and safety of the LMA in ICU patients, some of whom require high degrees of ventilatory support, are questionable. With the evidence currently available, one cannot draw a firm conclusion. Capnography A crucial step toward successful percutaneous tracheostomy is the introduction of the needle and guide wire into the trachea. Capnography has been proposed as one way to confirm tracheal needle placement. Mallick et al compared the use of capnography and bronchoscopy to confirm needle placement for percutaneous tracheostomy using the Blue Rhino kit. The operating times and the incidence of perioperative complications were similar for both groups. Capnography proved to be as effective as bronchoscopy in confirming correct needle placement. COMPLICATIONS OF TRACHEOSTOMY The decision to place a tracheostomy should be made by considering the balance between benefits versus risks of the procedure. The overall rate of complications associated with tracheostomy is relatively low. 1 Some complications are related to the procedure and others to the cannula. Complications can be classified as early (within 7 days) and late. Early Complications 4 Haemorrhage: This can be minor and can be controlled by packing and by insuring that the cuff of the tracheotomy tube is inflated. Major bleeding may require reoperation. Bleeding is reported in ±5% of tracheostomies. Wound infection: A tracheotomy is considered a clean-contaminated wound. Prophylactic antibiotics are usually not warranted. True infection is rare and requires only local therapy. In case of necrotizing tracheal infection, Page 16 of 35

9 conversion to oral tracheal intubation is necessary followed by wide debridement of involved tissues. Subcutaneous emphysema: Subcutaneous emphysema can be caused by positive pressure ventilation or coughing against a tightly sutured or packed wound. It can be prevented by not suturing the wound around the tube. The emphysema will resolve spontaneously within a few days. A chest radiograph should be obtained to rule out a pneumothorax. Tube obstruction: The tube can be obstructed by mucus, blood clots, displacement into surrounding soft tissues or abutment of the tube's open tip against the tracheal wall. Failure to re-establish adequate ventilation by suctioning through the tube requires immediate replacement of the inner cannula or the entire tube. Fausse route during the procedure or early tube displacement. Fausse route or early displacement (within 5 days after placement of tracheotomy) of the tube creates an airway emergency. Orotracheal intubation should be performed when the tract cannot be re-established immediately. Late Complications 4 Swallowing problems. Factors that contribute to disturbed swallowing are as follows: decreased laryngeal elevation, oesophageal compression and obstruction from the tracheotomy tube cuff. Patients are at risk for aspiration. It is recommended that a formal swallowing evaluation be conducted in all tracheostomized patients in whom oral nutrition is contemplated. Tracheal stenosis. Tracheal stenosis occurs in approximately 1 2% and usually results from ischaemia, devascularisation and chemical erosion. Causes include the use of high-pressure cuffs (now eliminated after the introduction of large-volume, low-pressure cuffs), forced angulation of a stiff tube or hyperinflation of the cuff which result in tracheal damage. Stenosis may occur at the stoma, the cuff side or the tip of the tracheotomy tube. Tracheo-innominate artery fistula. This complication is rare (<0.7%). Most fistulas appear to result from direct pressure of the cannula against the innominate artery. Risk factors include low placement of tracheotomy, highpressure cuffs and excessive head or tracheotomy tube movement. Overall survival is only 25%. Preventive measures include correct placement of the tracheotomy tube at the level of the second or third cartilaginous ring, avoiding prolonged or excessive hyperextension of the neck, using a soft, Page 17 of 35 readjustable tracheotomy tube and lightweight tubing to avoid dragging on the tracheotomy tube. Tracheoesophageal fistula. Tracheoesophageal fistula is a rare complication occurring in less than 1% of patients. Cause is mostly iatrogenic due to erosion by the tracheotomy cuff but also a right angle of the tube can cause undue pressure against the posterior tracheal wall. It is more commonly seen when a nasogastric tube is in place as well. Fistula repair is performed by a cervical incision with interposition of viable tissue. Post-intubation tracheoesophageal fistula is usually best treated with tracheal or laryngotracheal resection and anastomosis and primary oesophageal closure even in the absence of tracheal damage. Granuloma formation. Granulomas may result from a foreign body reaction to the tracheotomy tube or specific parts of it. They are more common with fenestrated tracheotomy tubes. These granulomas can be treated with the YAG laser. Especially worrisome are granulomas at the lower end of the tracheotomy tube where bronchoscopic removal only provides temporary relief. Persistent stoma. This situation usually results when the tube has been left in position for a prolonged period, permitting epithelialisation between the skin and the tracheal mucosa. Although the opening might become very small due to wound contracture, it may be troublesome for the patients. Surgical closure is proposed. Complications more common with Percutaneous Dilational Tracheostomy 13 Bending of guide wire Knotted or trapped guide wire Dilator failure Lateral stoma placement Tracheal ring fracture Posterior tracheal wall injury Complications more common with Surgical Tracheostomy 13 Injury to nerve, artery, or vein Oesophageal injury Thyroid injury Page 18 of 35

10 DECANNULATION One can consider tracheostomy decannulation only if the original upperairway obstruction is resolved, if airway secretions are controlled, and if mechanical ventilation is no longer needed. 14 A study was conducted between May and December 2006, examining tracheostomy decannulation opinions at major centers around the world. 15 It was found that clinicians consider a patient's level of consciousness, cough effectiveness, secretions, and oxygenation when determining whether to recommend tracheostomy removal. Decannulation failure is defined as the need to reinsert an artificial airway within 48 to 96 hours of planned tracheostomy removal. Clinicians are willing to accept a 2% to 5% failure rate. PERCUTANEOUS VERSUS SURGICAL TRACHEOSTOMY It is highly debated whether percutaneous dilational tracheostomy or open surgical tracheostomy is superior in terms of complications and outcome. Several studies have compared safety and outcome with percutaneous tracheostomy versus those with surgical tracheostomy, but lack of rigorous design makes useful comparisons quite impossible. 16 Two recent metaanalyses will be focused on. Delaney et al published a systematic review and meta-analysis in Critical Care in Seventeen randomized controlled trials involving 1,212 patients were included. The quorum flow diagram is show below. Before one can embark on the decannulation process certain criteria should be fulfilled 4 Stable arterial blood gases. Absence of distress. Haemodynamic stability. Absence of fever or active infection. PaCO 2 < 60 mmhg. Absence of delirium or psychiatric disorder. Normal endoscopic examination or revealing stenotic lesion occupying <30% of the airway. Adequate swallowing. Able to expectorate. Before removal, one can try the deflated-cuff tracheostomy occlusion procedure. The cuff should be deflated and the opening of the tube occluded. Signs of respiratory distress should be watched for. If the patient becomes distressed, there should be immediate return to breathing through the tracheostomy tube and endoscopic examination should be performed to exclude any upper airway obstruction. If no lesions are present, one should consider whether the tube is not too large and try again after changing the tube. 4 Once the tube is removed the opening can be covered with sterile dressings. The wound spontaneously heals in ±10 days in most cases. Locally, a Blue Line is inserted once the tracheostomy tube is removed. This is a narrow bore uncuffed tube that can be used for suctioning. It also keeps the tracheostomy tract patent and thus provides easier access if the tracheostomy tube needs to be re-inserted. Page 19 of 35 Figure 14: Quorum flow diagram 17 This systematic review and meta-analysis has demonstrated that the technique of percutaneous tracheostomy has a number of important advantages over performing a surgical tracheostomy in critically ill patients who require an elective tracheostomy. Percutaneous tracheostomy was associated with a reduction in the incidence of clinically important wound infections compared with traditional surgical tracheostomy. Page 20 of 35

11 Figure 15: Forest plot showing the effect of percutaneous tracheostomy compared to surgical tracheostomy on the incidence of wound infection 17 There was no evidence overall that PDT resulted in an increased incidence of clinically significant bleeding, major peri-procedural or long term complications. Figure 17: Forest plot showing the effect of percutaneous dilatational tracheostomy (PDT) compared to surgical tracheostomy (ST) on mortality 17 The results of subgroup analysis suggested that percutaneous tracheostomy was superior to surgical tracheostomy when the latter was performed in theatre. Percutaneous tracheostomy was associated with a reduction in bleeding and overall mortality and a suggestion of decreased duration of translaryngeal intubation prior to tracheostomy. The method of percutaneous tracheostomy used and use of bronchoscopy to guide the placement did not significantly affect the pooled effect estimates for wound infection, bleeding or mortality. These results indicate that percutaneous tracheostomy, performed electively in the ICU, should be the method of choice for performing tracheostomies in critically ill adult patients. Figure 16: Forest plot showing the effect of percutaneous dilatational tracheostomy (PDT) compared to surgical tracheostomy (ST) on the incidence of significant bleeding 17 The second meta-analysis was published by Higgins and Punthakee in The Laryngoscope in The primary objective was to compare complication rates of open versus percutaneous tracheostomy in adult ventilated patients using meta-analysis methodology. Cost-effectiveness and procedure length comparisons were included as secondary objectives. Page 21 of 35 Page 22 of 35

12 Study inclusion and exclusion criteria are outlined below: Inclusion Criteria Population Elective consenting adult ventilated patients Intervention Percutaneous technique compared with open technique Method Experimental design: random or quasi-random clinical trials only Outcome Complications described and numbers reported Published English language For ease of reporting and shown to not lead to biased estimates of effectiveness of treatments Exclusion Criteria Emergency airway Tracheostomy is not considered standard of care Pediatric population Immaturity of larynx and varied position in neck restricting choice of intervention The percutaneous method was significantly better for wound infection/stomatitis (P =.0002) and scarring (P =.01). Complications of decannulation/obstruction were significantly more likely to occur in percutaneous tracheostomies and strongly favored the open surgical technique (P=.009). This is probably because the open technique allows the insertion of a tracheostomy tube with an inner and outer cannula that facilitates nursing. In addition, the larger, more well-defined insertion tract allows for earlier tracheostomy change that also reduces mucous plugging. Figure 19: Comparison for wound infection/stomatitis 18 Figure 20: Comparison for unfavourable scarring 18 Figure 18: Comparison for decannulation/obstruction 18 There was no statistically significant difference in terms of false passage, minor haemorrhage, major haemorrhage, subglottic stenosis, and death. Overall complications trended toward favoring the percutaneous technique; however, this only approached statistical significance (0.75, , P=.05) Page 23 of 35 Page 24 of 35

13 Klein et al reported six cases in which the Griggs method was used in the emergency setting. 20 They used the technique in patients who could not be intubated because of ingestion of a caustic substance, presence of a difficult airway, laryngeal carcinoma, or major facial trauma. There were no procedure-related complications. The Griggs method may be particularly suited to emergency situations because it can be performed quickly and does not rely on as much external force on the anterior tracheal wall as other methods. Bardell and Drover have used the Ciaglia method with good results at their institution in Ontario, Canada. 10 Figure 21: Comparison for overall complications including adjusted values for minor haemorrhage 18 There were only four studies that included any cost-effectiveness estimates. The overall pooled result favored the percutaneous technique. Case length comparison also strongly favors the percutaneous technique by 4.59 minutes. This comparison was also negatively impacted by heterogeneity. Tracheostomy can be very useful where there is tracheal obstruction from malignancy. Several commercial tracheostomy prostheses are available which are of long or adjustable length (up to 18 cm), permitting passage of a secure airway past tracheal obstructions and can be life-saving in urgent situations. 21 The prostheses (i.e., Bivona tubes ) are often wire reinforced to resist the radial compressive force of luminal tumor or paratracheal mass. The long-segment tubes can be placed even in awake, sedated patients with adequate local anesthetic followed by tracheostomy and expeditious bronchoscopic guidance past tracheal obstruction. This provides a stable patent airway that permits a spontaneously breathing nonsedated patient to be managed definitively at a later time. It was concluded from this meta-analysis that percutaneous tracheostomies trend toward fewer overall complications than open techniques and appear to be more cost-effective by releasing operating theatre resources including time and personnel, provide greater feasibility in terms of bedside capability, and allow non-surgeons to safely perform the procedure. EMERGENCY TRACHEOSTOMY Percutaneous tracheostomy has been considered an elective procedure with the surgical route chosen for the management of imminent airway loss. Ben-Nun et al reported 10 cases of emergency percutaneous tracheostomy in trauma patients with impending loss of the airway where orotracheal intubation had failed. 19 A modified Grigg s technique was used by experienced thoracic surgeons. It was concluded that emergency percutaneous tracheostomy using a modified Griggs' technique is feasible and safe. In experienced hands, it might be even easier and faster than the open surgical tracheostomy. Page 25 of 35 Figure 22: Bivona tube 21 Page 26 of 35

14 TIMING OF TRACHEOSTOMY They are summarized in the table below. The timing of tracheostomy in critically ill patients is controversial. There is no consensus in the literature as to the definition of early and late with respect to timing of tracheostomies. Tracheostomy in the1980s was considered early if it was performed before 21 days of translaryngeal intubation. In the otorhinolaryngology literature, however, the performance of tracheostomy to protect the larynx from intubation damage has been recommended within 3 days of intubation. 22 Several studies have compared early and late tracheostomy looking at its effect on the duration of mechanical ventilation, ICU and hospital length of stay. The limitations in these studies include: retrospective design of some studies, the randomization methods in some of the randomized trials, the variable definition of early versus late tracheostomy, and the absence of blinding. 23 Griffiths et al, in 2005, published a systematic review and meta-analysis of studies of the timing of tracheostomy in adult patients undergoing artificial ventilation. 24 Five trials with a combined study population of 406 patients were included. These studies spanned a 20 year period between 1984 and See page 28 for Table 4 showing studies comparing early and late tracheostomy. Study Bouderka et al 2004 Dunham et al 1984 Rodriguez et al 1990 Rumbak et al 2004 Saffle et al 2002 No of Patients (n=406) Timing of tracheostomy Early Late days after admission days after initiation of translaryng eal intubation days after admission to intensive care unit days after initiation of mechanical ventilation 44 Next available operative day Prolonged endotracheal intubation 14 days after initiation of translaryngeal intubation 8 or more days after admission to intensive care unit days after initiation of mechanical ventilation 14 days after burn injury Intensive care setting Unit for patients with head injuries Trauma unit Surgical unit Three medical units Burns unit Randomization Randomized; method not stated Quasirandomized Quasirandomized True randomization True randomization Mortality expressed on intention to treat basis Implied Mortality not recorded Pneumonia analyzed by intention to treat Implied Implied Implied Duration of ventilation and critical care stay expressed on intention to treat basis Implied both Yes Implied both Yes Yes Table 4: Studies comparing early and late tracheostomy 24 These studies compared early and late tracheostomy with respect to mortality, risk of hospital acquired pneumonia, duration of mechanical ventilation and length of ICU stay. The results are depicted in the Forest plots below. Page 27 of 35 Page 28 of 35

15 Figure 26: Length of stay in ICU 24 Figure 23: Mortality with early and late tracheostomy 24 These studies were limited by the relatively small study populations and the high level of heterogeneity. Exclusion and inclusion criteria differed across the trials and because each trial used a different definition of what constituted an early or late tracheostomy. The trials were conducted in different specialist rather than general intensive care units. It was also found that there were different diagnostic criteria for hospital acquired pneumonia. However, if the results from this meta-analysis can be generalized, it may be advisable to place a tracheostomy earlier rather than later. Figure 24: Hospital acquired pneumonia with early and late tracheostomy 24 Figure 25: Duration of ventilation days 24 Early tracheostomy was assessed in trauma patients by Dunham et al in A systematic review and meta-analysis was conducted. This was restricted to trauma patient studies comparing early and late tracheostomy. The results are not presented in detail here but the conclusions made will be commented on. This analysis suggests that early tracheostomy is associated with a decrease in ventilator/icu days for severe brain-injured patients. For trauma patients, there is no advantage or detriment with early tracheostomy relative to mortality rates, pneumonia rates, and laryngotracheal pathology. In non-brain injured patients, ventilator/icu days are not increased or decreased with early tracheostomy. It was concluded from this study that it is reasonable to use the translaryngeal route up to 10 days when tracheal intubation is needed, to perform tracheostomy when prolonged intubation is needed, and to assess daily the appropriateness for tracheostomy, when the time needed for intubation is uncertain. Data from the review indicate that ET should be strongly considered with severe brain injury. Page 29 of 35 Page 30 of 35

16 A study by Schauer et al, looking at the timing of tracheostomy stratified by injury severity, was published in the Journal on Trauma in January this year. 26 In contrast to previous studies, the relationship between the probability of survival and timing of tracheostomy was looked at. Timing of tracheostomy was classified into 4 groups. Class Abbreviation Post injury days Early tracheostomy ET 0-3 Early intermediate tracheostomy EIT 4-7 Late intermediate tracheostomy LIT 8-12 Late tracheostomy LT >12 Table 5: Classification of timing of tracheostomy 26 Using Trauma and Injury Severity Score methodology, low probability of survival indicates that survival is expected to be less than 25%. High probability indicates that survival is expected to be greater than or equal to 25%. It was concluded that early tracheostomy among patients with a high probability of survival significantly reduces ICU length of stay, hospital length of stay, ventilator days, and the incidence of pneumonia. The issue of timing of tracheostomy is still not resolved as studies have been inadequate and thus have not been able to provide clear direction to the clinician. The main obstacle to early tracheostomy in patients likely to benefit is the inability to accurately predict the need for prolonged mechanical ventilation during the first few days of mechanical ventilation. The best predictors appear to be nonspecific markers of poor outcome: high acuity of illness (Acute Physiology and Chronic Health Evaluation [APACHE] II scores >25) and the presence of shock at the time of ICU admission. 2 The Mayo clinic has suggested a reasonable approach to the timing of tracheostomy. Figure 27: Approach to timing of tracheostomy 2 INTERNATIONAL PRACTICE With no clear directives on techniques and timing of tracheostomy, decision making becomes a challenge for the intensivist, anaesthetist and surgeon. Two recent surveys have tried to gauge what current practice is. A survey was conducted by mailing a questionnaire to the head physicians of 513 ICUs in Germany in October 2006, excluding pediatric ICUs. 27 The technique of percutaneous dilation tracheostomy is well established in German ICUs and is the first choice for tracheostomy performed in longterm ventilated patients. Page 31 of 35 Page 32 of 35

17 Among the various techniques, the modified Ciaglia technique is the preferred approach, and nearly all physicians routinely use bronchoscopic guidance to do it. Currently, most tracheostomies are performed during the first 2 weeks of ventilation, and follow-up of tracheostomized patients is not usually performed. A similar survey was carried out across 228 general intensive care units (ICUs) throughout the United Kingdom excluding specialist units. 28 Percutaneous tracheostomy is the preferred technique in the majority of units when compared to surgical tracheostomy, with a single dilatation technique being favoured by the majority. There is mixed practice with regards to the timing of ICU tracheostomy. There is still a fairly low level of routine follow-up after ICU discharge, which may mean significant morbidity is being missed. CONCLUSION It is vital for all anaesthetists, surgeons and intensivist to be familiar with tracheostomy as it presents itself in daily practice. The controversial areas of indication, timing and technique of tracheostomy needs further research with larger randomized controlled trials across various ICU settings. As a clinician in the intensive care unit, operating theatre and emergency room, decision making should be individualized and practice should be according to local expertise. REFERENCES 1. Groves DS, Durbin CG, Jr. Tracheostomy in the critically ill: indications, timing and techniques. Curr Opin Crit Care Feb;13(1): Rana S, Pendem S, Pogodzinski MS, Hubmayr RD, Gajic O. Tracheostomy in critically ill patients. Mayo Clin Proc Dec;80(12): Epstein SK. Anatomy and physiology of tracheostomy. Respir Care Apr;50(4): De Leyn P, Bedert L, Delcroix M, Depuydt P, Lauwers G, Sokolov Y, et al. Tracheotomy: clinical review and guidelines. Eur J Cardiothorac Surg Sep;32(3): Diehl JL, El Atrous S, Touchard D, Lemaire F, Brochard L. Changes in the work of breathing induced by tracheotomy in ventilatordependent patients. Am J Respir Crit Care Med Feb;159(2): Davis K, Jr., Campbell RS, Johannigman JA, Valente JF, Branson RD. Changes in respiratory mechanics after tracheostomy. Arch Surg Jan;134(1): Durbin CG, Jr. Techniques for performing tracheostomy. Respir Care Apr;50(4): Gromann TW, Birkelbach O, Hetzer R. Balloon dilatational tracheostomy: initial experience with the Ciaglia Blue Dolphin method. Anesth Analg Jun;108(6): Ciaglia P, Firsching R, Syniec C. Elective percutaneous dilatational tracheostomy. A new simple bedside procedure; preliminary report. Chest Jun;87(6): Bardell T, Drover JW. Recent developments in percutaneous tracheostomy: improving techniques and expanding roles. Curr Opin Crit Care Aug;11(4): Kost KM. Endoscopic percutaneous dilatational tracheotomy: a prospective evaluation of 500 consecutive cases. Laryngoscope Oct;115(10 Pt 2): Al-Ansari MA, Hijazi MH. Clinical review: percutaneous dilatational tracheostomy. Crit Care Feb;10(1): Durbin CG, Jr. Early complications of tracheostomy. Respir Care Apr;50(4): Christopher KL. Tracheostomy decannulation. Respir Care Apr;50(4): Page 33 of 35 Page 34 of 35

18 15. Stelfox HT, Crimi C, Berra L, Noto A, Schmidt U, Bigatello LM, et al. Determinants of tracheostomy decannulation: an international survey. Crit Care. 2008;12(1):R Pelosi P, Severgnini P. Tracheostomy must be individualized! Crit Care Oct;8(5): Delaney A, Bagshaw SM, Nalos M. Percutaneous dilatational tracheostomy versus surgical tracheostomy in critically ill patients: a systematic review and meta-analysis. Crit Care. 2006;10(2):R Higgins KM, Punthakee X. Meta-analysis comparison of open versus percutaneous tracheostomy. Laryngoscope Mar;117(3): Ben-Nun A, Altman E, Best LA. Emergency percutaneous tracheostomy in trauma patients: an early experience. Ann Thorac Surg Mar;77(3): Klein M, Weksler N, Kaplan DM, Weksler D, Chorny I, Gurman GM. Emergency percutaneous tracheostomy is feasible in experienced hands. Eur J Emerg Med Apr;11(2): Theodore PR. Emergent management of malignancy-related acute airway obstruction. Emerg Med Clin North Am May;27(2): Durbin CG, Jr. Indications for and timing of tracheostomy. Respir Care Apr;50(4): Shirawi N, Arabi Y. Bench-to-bedside review: early tracheostomy in critically ill trauma patients. Crit Care Feb;10(1): Griffiths J, Barber VS, Morgan L, Young JD. Systematic review and meta-analysis of studies of the timing of tracheostomy in adult patients undergoing artificial ventilation. BMJ May 28;330(7502): Dunham CM, Ransom KJ. Assessment of early tracheostomy in trauma patients: a systematic review and meta-analysis. Am Surg Mar;72(3): Schauer JM, Engle LL, Maugher DT, Cherry RA. Does acuity matter?--optimal timing of tracheostomy stratified by injury severity. J Trauma Jan;66(1): Kluge S, Baumann HJ, Maier C, Klose H, Meyer A, Nierhaus A, et al. Tracheostomy in the intensive care unit: a nationwide survey. Anesth Analg Nov;107(5): Veenith T, Ganeshamoorthy S, Standley T, Carter J, Young P. Intensive care unit tracheostomy: a snapshot of UK practice. Int Arch Med. 2008;1(1):21 Page 35 of 35