open access atlas of otolaryngology, head & neck operative surgery

OPEN ACCESS ATLAS OF OTOLARYNGOLOGY, HEAD &NECK OPERATIVE SURGERYTRACHEOSTOMYTracheostomy refers to the creation of acommunication between the trachea andthe overlying skin. This may be done eitherby open or percutaneous technique. Thischapter will focus on the open surgicaltechnique in the adult patient.IndicationsTracheostomy is done for airwayobstruction, respiratory support (assistedventilation), pulmonary hygiene, eliminationof dead space, and treatment ofobstructive sleep apnoea.Preoperative evaluationLevel of obstruction: A standardtracheostomy will not bypass obstructionin the distal trachea or bronchial treeAnatomy of the neck: The surgeon shouldanticipate a difficult tracheostomy inpatients with short necks, thick necks, andnecks that cannot be extended due to e.g.rheumatoid or osteoarthritis of the cervicalspineDeviation of cervical trachea: A chest X-ray will alert the surgeon to trachealdeviation due to cervical and mediastinaltumours, or traction on the trachea due tofibrosis (Figure 1).Figure 1: Tracheal deviation due totuberculosisJohan FaganCoagulopathy: A coagulopathy should becorrected prior to surgery. If notcompletely corrected, then haveelectrocoagulation available at surgery toaid haemostasisCardiorespiratory status: Patients withupper airway obstruction may have corpulmonale, or respiratory acidosis. Somepatients may be dependent onphysiological PEEP to maintain O 2saturation, or an elevated pCO 2 to maintainrespiratory drive; relieving upper airwayobstruction with a tracheostomy mayparadoxically cause such patients to stopbreathing and become hypoxic.Laryngeal cancer: If airway obstruction isas a consequence of laryngeal cancer, thenone should attempt not to enter the tumourduring tracheostomy. This may require alower tracheostomy if tumour involves thecervical trachea. It is prudent to send asample from the tracheal window forhistological examination as involvementby tumour might be useful information forthe surgeon subsequently doing thelaryngectomy.Tracheostomy procedureA tracheostomy is best done in theoperating room with good lighting,instrumentation, suction, and assistance.Patients may cough on inserting thetracheostomy tube; hence eye protection isrecommended to prevent transmission ofinfections such as HIV and hepatitis.Anaesthesia: Unless the patient can safelybe intubated or the patient be ventilatedwith a mask, a tracheostomy should bedone under local anaesthesia. If there isconcern about the anaesthetist’s ability tomaintain an airway, then the surgeonshould be present during induction; the

skin, soft tissue and trachea (into thelumen) should be infiltrated with localanaesthesia with adrenaline beforeinduction; and a set of tracheostomyinstruments should be set out beforeinduction of anaesthesia so that anemergency tracheostomy can be done ifrequired.Positioning and draping: The patient isplaced in a supine position with neckextended by a pillow or sandbag placedunder the shoulders in order to deliver thetrachea out of the thorax and to give thesurgeon adequate access to the cervicaltrachea. Such extension may not bepossible in patients with neck injuries, orrheumatoid and osteoarthritis of thecervical spine. Some patients withimpending airway obstruction may nottolerate a recumbent position; thetracheotomy may then be done with thepatient in a sitting position with neckextended. The skin of the anterior neck andchest is sterilised and the neck draped. Ifthe tracheostomy is being done under localanaesthesia, the face should not becovered.Surface landmarks: The tracheostomy iscreated below the 1 st tracheal ring, so as toavoid subglottic stenosis as a result ofscarring. Therefore palpating to determinethe location of the cricoid cartilage isimportant. When you run your fingers upthe midline of the neck starting inferiorlyat the sternal notch, you 1 st encounterprominence of the thyroid isthmus,followed by the cricoid.Figure 2: Minimum set of instrumentsSkin incision: A horizontal incision ismade one fingerbreadth below the cricoidprominence. This is cosmeticallypreferable to a vertical midline incision.The incision is carried through the skin andthe subcutaneous tissue. Note that theplatysma is generally absent in the midline.Take care not to transect the anteriorjugular veins, which are just superficial tothe strap muscles within the investingcervical fascia, and can be preserved andretracted laterally (Figure 3). Theremainder of the dissection should remainstrictly in the midline in a vertical planeto avoid injury to the inferior thyroid veins.Minimum instruments: A minimum set ofinstruments is demonstrated in Figure 2.Figure 3: Exposure of anterior jugularveins and cervical fascia2

Infrahyoid strap muscles: Figure 4illustrates the infrahyoid strap muscles.Thyroid cartilageCricoid cartilageThyroid glandSternohyoid muscleSternothyroid muscleFigure 4: Infrahyoid strap musclesIdentify the midline cervical fascial planebetween the sternohyoid muscles. Dividethis intermuscular plane by spreading witha pair of scissors. Repeat this manoeuvre toseparate the sternothyroid muscles, andretract the muscles laterally (Figure 5).The trachea and cricoid can now bepalpated.Figure 5: Retracting sternohyoid andsternothyroid muscles to expose thethyroid glandThyroid isthmus: The thyroid isthmusoverlies the 2 nd /3 rd tracheal rings. Theisthmus should be retracted superiorly toexpose the trachea (Figure 6). Only veryrarely does the thyroid isthmus need to bedoubly clamped, divided, and (suture)ligated.Figure 6: Thyroid retracted superiorly andan inferiorly based flap cut (along redlines) in anterior tracheal wallExpose trachea: The infrathyroid tracheais exposed anteriorly by carefully partingoverlying soft tissues with a pair ofscissors, taking care not to tear the inferiorthyroid veins. Ensure that the surgical fieldis dry before proceeding, as it is difficult toachieve haemostasis once the tracheostomytube has been inserted. Should there bedoubt about the location of the trachea, orthere be concern it being confused with thecarotid artery, aspirating air with a needleattached to a syringe will confirm itslocation.Create tracheostoma: In the wake patient,lignocaine may again be injected intotracheal lumen prior to incising the tracheaand inserting the tube in order to reducecoughing. Upward traction may be appliedto a tracheal hook inserted under a trachealring to stabilise the trachea and deliver itfrom the chest. The safest means to createa tracheostomy in adults is by creating aninferiorly based flap raised from theanterior wall of the 3 rd and 4 th trachealrings. A silk traction suture is passedthrough this anterior tracheal flap andloosely secured to the skin (Figure 7).Traction on the suture facilitatesreinsertion of the tracheostomy tube incase of accidental decannulation.3

Alternately one may remove an anteriorcartilage segment of the 2 nd , 3 rd or 4 thtracheal rings.neck, and tied, with the neck flexed. If theties are placed with the neck extended,they are too loose when the patient flexesthe neck.EpiglottisGlottisBack wall of tracheaInferiorly based trachealflapTraction sutureanchoring flapThyroid cartilageCricoidThyroid glandInnominate arterySternumFigure 8: Position of tracheostomy tubeFigure 7: Flap reflected inferiorly withtraction suture attached to flapInsertion of tracheostomy tube: Thesurgeon assesses the size of the trachea,and selects the largest sized cuffedtracheostomy tube that will comfortably fitthe tracheal lumen. Inject air into thetracheostomy inflatable cuff to test theintegrity of the cuff. Insert the introducerinto the tracheostomy tube. If the patienthas been intubated, the anaesthetist isasked to slowly withdraw the endotrachealtube, so that the tracheostomy tube can beinserted under direct vision. Advance thetube into the trachea while applyingtraction to the silk traction suture attachedto the tracheal flap. Ensure that the tubehas been inserted into the tracheal lumen,and not a false passage in the paratrachealsoft tissues. Inflate the cuff, attach theanaesthetic tubing, and hand-ventilate untilone has confirmed correct placement of thetube within the trachea (Figure 8). Do notsuture the skin tightly around thetracheostomy tube, as this can promotesurgical emphysema.Securing the tracheostomy tube: Tapes arethreaded through the holes in the flanges ofthe tracheostomy tube, passed around theThe ties should be tight enough to admit nomore than a single finger under the tape(Figure 9).Figure 9: Tracheostomy tube secured withVelcro tapeIt is prudent to suture the tracheotomy tubeto the skin for the first few days to allowmaturation of the tracheocutaneous tract.The sutures can then be removed andtraditional tracheotomy tapes can then beused. Following free microvasculartransfer flap reconstruction, tracheostomytapes should be avoided; the tracheostomyshould preferably be sutured to thesuprastomal skin, as tracheal tapes maycause jugular vein compression,thrombosis, and venous outflowobstruction and flap failure.4

PitfallsHigh tracheostomy: It is important not toplace the tracheotomy above the 2 ndtracheal ring, as inflammation may causesubglottic oedema, chondritis of the cricoidcartilage, and subglottic stenosis.Low tracheostomy: A tracheotomy shouldnot be placed below the 4 th tracheal ringas:The distance between the skin and thetrachea increases inferiorly, whichmakes tracheal intubation moredifficultA low tracheostomy may compress anderode the innominate artery whichpasses between the manubrium sterniand the trachea (Figure 8). This maycause innominate artery erosion andfatal haemorrhage. This may bepreceded by a so-called “sentinelbleed”Paratracheal false tract: Inadvertentextratracheal placement of thetracheostomy tube can be fatal. It isrecognised by the absence of breath soundson auscultation of the lungs, highventilatory pressures, failure to ventilatethe lungs, hypoxia, absence of expiredCO 2 , surgical emphysema, and an inabilityto pass a suction catheter down thebronchial tree, and on chest X-ray.Surgical emphysema, pneumomediastinum,and pneumothorax: Injury to the pleuraldomes is more likely to occur in children,struggling patients and patients on positivepressure ventilation. It can be complicatedby a tension pneumothorax. Henceauscultation of the chest and a CXR shouldbe performed after tracheostomy,especially in ventilated patients. Surgicalemphysema may also be promoted bysuturing the tracheostomy wound aroundthe tracheostomy tube.Airway fire: Do not enter the trachea withdiathermy, as this may cause an airway firein a patient being ventilated with a highconcentration of oxygen.Choice of Tracheostomy TubeA variety of tube designs and materials areavailable. The choice of tube shouldconform to the indication for which it is tobe used. All tubes should have an innercannula; this can safely be removed andcleaned without a need to remove the outercannula and hence endanger the airway.The following factors may influence thechoice of tube:Tube diameter: Because airway resistanceis related to the 4 th power of the radiuswith laminar flow, and the 5 th power of theradius with turbulent flow, it is importantto select a tube that that fits the tracheasnugly. A range of sizes should beavailable. It also underscores theimportance of keeping the tube clean, asaccumulation of mucus increases airwayresistance not only by reducing thediameter, but also by causing turbulent airflow.Tracheal seal: A cuffed, plastictracheostomy tube is used to create a sealwith the trachea in patients on positivepressure ventilation, and with freshtracheostomy wounds (Figure 10) toprevent saliva or blood entering the lowerairways. The cuffed tube may be replacedwith an uncuffed tube, either plastic ormetal (Figure 11) in patients who do notrequire positive pressure ventilation oncethe tract between the skin and the tracheahas become well defined by granulationtissue at 48hrs, and tracheostomal bleedinghas settled.5

curvature to conform to the stoma and thetrachea.Figure 10: Plastic low pressure cuffedtracheostomy tube with outer cannula,inner cannula and introducer (L to R)Figure 12: Tracheostomy tube withadjustable flangeNeck Flange: The neck flange shouldconform to the shape of the neck and fitsnugly against the skin to avoid excessivetube movement, accidental decannulation,and soft tissue trauma.Tube material: Metal tubes are thinnerwalled, and hence have a better ratio ofouter to inner wall diameter, therebyoptimising airway resistance.Figure 11: Metal tracheostomy tube withouter cannula, inner cannula andintroducer (L to R)Tube length: Patients with very thick neckscan be fitted with a tracheostomy tube witha flange that can be adjusted up or downthe shaft of the tube (Figure 12). Tubelength may also need to be adjusted whenthe carina is close to the tracheostoma orwith tracheal stenosis or tracheamalaciadistal to the tracheostoma that needs tostented by the tube. Chest and neck X-raysare of value to determine the requiredlength.Tube shape: Laryngectomy patientsrequire shorter tubes with a gentlerPhonation: Patients with uncuffed tubes orfenestrated tubes (Figure 13) can phonateby occluding the end of the tracheostomytube with a finger which permits air tobypass the tube and to pass through thelarynx.Figure 13: Fenestrated tracheostomy tube6

Speaking valves fitted to the ends oftracheostomy tubes are one-way valvesthat open on inspiration, but close onexpiration, thereby directing expired airthrough the larynx and permit hands-freespeech (Figure14).Figure 14: Speaking valve that fits onto theend of a tracheostomy tube and permitshands-free speechFenestrated tubes with speaking valves areparticularly well suited to patients withobstructive sleep apnoea, as they can havenormal speech by day with the valve inplace, but uncap the tracheostomy tube atnight to ensure unobstructed breathing.Postoperative carePulmonary oedema: This may occurfollowing sudden relief of airwayobstruction and reduction in highintraluminal airway pressures. It may becorrected by CPAP or positive pressureventilation.Respiratory arrest: This may occurimmediately following insertion of thetracheostomy tube, and is attributed to therapid reduction in arterial pCO 2 followingrestoration of normal ventilation, andhence loss of respiratory drive.Humidification: Tracheostomy bypassesthe nose and upper aerodigestive tractwhich normally warms, filters, andhumidifies inspired air. To avoid trachealdesiccation and damage to the respiratorycilia and epithelium, and obstruction due tomucous crusting, the tracheostomy patientneeds to breathe humidified warm air bymeans of a humidifier, heat and moistureexchange filter, or a tracheostomy bib.Pulmonary Toilette: The presence of atracheostomy tube and inspiration of dryair irritates the mucosa and increasessecretions. Tracheostomy also promotesaspiration of saliva and food as tethering ofthe airway prevents elevation of the larynxduring swallowing. Patients are unable toclear secretions as effectively astracheostomy prevents generation ofsubglottic pressure, hence makingcoughing and clearing secretionsineffective; it also disturbs ciliary function.Therefore secretions need to be suctionedin an aseptic and atraumatic manner.Cleaning the tube: Airway resistance isrelated to the 4 th power of the radius withlaminar flow, and the 5 th power of theradius with turbulent flow. Therefore evena small reduction of airway diameterand/or conversion to turbulent airflow as aresult of secretions in the tube cansignificantly affect airway resistance.Therefore regular cleaning of the innercannula is required using a pipe cleaner orbrush.Securing the tube: Accidental decannulationand failure to quickly reinsert the tubemay be fatal. This is especiallyproblematic during the 1 st 48hrs when thetracheocutaneous tract has not matured andattempted reinsertion of the tube may becomplicated by the tube entering a falsetract. Therefore the tightness of thetracheostomy tapes should be regularlychecked. Traction sutures on the trachealflap facilitate reinsertion of thetracheotomy tube.Cuff pressures: When tracheostomy tubecuff pressures against the tracheal wallmucosa exceed 30cm H 2 0, mucosalcapillary perfusion ceases, ischaemicdamage ensues and tracheal stenosis mayresult. Mucosal injury has been shown to7

occur within 15 minutes. Therefore cuffinflation pressures of >25cm H 2 0 should beavoided. A number of studies havedemonstrated the inadequacy of manualpalpation of the pilot balloon as a means toestimate appropriate cuff pressures.Measures to prevent cuff related injuryinclude:Only to inflate the cuff if required(ventilated, aspiration)Minimal Occluding Volume Technique:Deflate the cuff, and then slowlyreinflate until one can no longer hearair going past the cuff with astethoscope applied to the side of theneck near the tracheostomy tube(ventilated patient)Minimal Leak Technique: The sameprocedure as above, except that oncethe airway is sealed, slowly towithdraw approximately 1ml of air sothat a slight leak is heard at the end ofinspirationPressure gauge: Regular or continuousmonitoring of cuff pressuresAuthor & EditorJohan Fagan MBChB, FCORL, MMedProfessor and ChairmanDivision of OtolaryngologyUniversity of Cape TownCape TownSouth Africajohannes.fagan@uct.ac.zaThe Open Access Atlas of Otolaryngology, Head &Neck Operative Surgery by Johan Fagan (Editor)johannes.fagan@uct.ac.za is licensed under a CreativeCommons Attribution - Non-Commercial 3.0 UnportedLicenseDecannulationThe tracheostomy tube can be removedonce the cause of the airway obstructionhas been resolved. If any doubt existsabout the adequacy of the airway, e.g.following pharyngeal or laryngeal surgery,then the tracheostomy tube is firstdownsized and plugged, so that the patientcan breathe freely past the tube. The tubeis then plugged. The patient should beunder close observation during this time,and may be monitored with pulseoximetry. If the patient can tolerate thetracheostomy tube being pluggedovernight, it can then be removed. Thetracheostomy wound is covered with anocclusive dressing, and generally healsover a matter a week.8