Percutaneous Dilatational Tracheostomy (PDT)

Historical Background

Relevant Anatomy

Tracheal anatomy - thyroid gland, cricoid cartilage, and thyroid isthmus. (Current Surgical Therapy 14e)

The Trachea

• A midline unpaired structure extending from the superficial neck posteriorly into the mediastinum
• Average length: 11 ± 1 cm in males, 10 ± 1 cm in females
• Contains 18-22 incomplete semicircular cartilaginous rings anteriorly
• The posterior wall (membranous trachea) is fibroelastic and abuts the anterolateral esophagus - this is the most vulnerable structure during PDT
• Tracheal diameter: 2.5-2.7 mm in men, 2.1-2.3 mm in women (relevant for tube size selection)
• The cricoid cartilage is the only complete cartilaginous ring, connecting inferiorly to the first tracheal ring and superiorly to the thyroid cartilage via the cricothyroid membrane

Palpable Surface Landmarks

• Thyroid cartilage - the most prominent anterior cervical landmark ("Adam's apple")
• Cricothyroid membrane - between thyroid and cricoid cartilages; site of emergency surgical airway
• Cricoid cartilage - inferior to thyroid cartilage; the last complete ring before the trachea
• Tracheal rings 1-3 - the target zone for tracheostomy
• Sternal notch - inferior landmark; incision is made approximately two fingerbreadths above this, over the 2nd-3rd tracheal rings
• Ideal entry point: between rings 1-2 or rings 2-3

Structures Anterior to the Trachea (at Risk)

• Thyroid isthmus - typically overlies the 2nd and 3rd tracheal rings; must be identified (retracted or divided in surgical tracheostomy, worked around in PDT)
• Innominate (brachiocephalic) artery - crosses the anterior trachea obliquely at about the level of the sternal notch, distal to the 3rd ring. A "high-riding" innominate artery is a key risk factor for tracheo-innominate fistula
• Inferior thyroidal artery and vein - may lie between skin and trachea
• Anterior jugular veins - superficial; can bleed on skin incision
• Strap muscles (sternohyoid and sternothyroid) - lie over the trachea and are retracted laterally in surgical tracheostomy

Unlike surgical tracheostomy, PDT does not provide direct visualization for haemostasis of these vessels - so preoperative assessment of vascular anatomy is essential.

Preoperative surface landmarks: (A) thyroid cartilage, (B) cricoid cartilage, (C) 1st tracheal ring, (D) 2nd tracheal ring, (E) sternal notch. (Current Surgical Therapy 14e)

Indications

General Tracheostomy Indications

1. Prolonged mechanical ventilation - the most common indication; chronic hypoxic/hypercapnic respiratory failure from pulmonary, cardiac, or systemic disease
2. Neurological airway protection - CVA, intracranial haemorrhage, TBI, debilitating neuromuscular diseases
3. Upper airway obstruction - head and neck malignancy, subglottic/tracheal stenosis, angioedema, bilateral vocal cord paralysis, obstructive sleep apnea, post-radiation stricture, burn injury, trauma
4. Facilitation of weaning - reduces dead space, decreases sedation requirements, improves secretion clearance, allows oral intake and phonation
5. Emergency failed airway - when orotracheal/nasotracheal intubation is impossible

PDT-Specific Indications / Patient Selection

• ICU patients requiring prolonged ventilation in whom bedside procedure is advantageous
• Patients with favorable neck anatomy: easily palpable thyroid cartilage, cricoid, and tracheal rings 1-3; no overlying vessels
• Haemodynamically stable patients
• PT/PTT < 1.5 times control, platelets > 50,000/mm³ (correctable coagulopathy is a relative contraindication but uremic patients can undergo PDT with DDAVP pretreatment)
• PEEP ≤ 12 cmH₂O and adequate oxygenation on FiO₂ 1.0

Contraindications to PDT

• Cellulitis/deep infection at insertion site
• Operator inexperience

• Inability to palpate tracheal landmarks (obesity, short neck, prior surgery/scarring)
• Overlying vessels (high-riding innominate artery, aberrant vasculature)
• Significant uncorrectable coagulopathy
• Worsening acute critical illness (septic shock, severe ARDS with PEEP > 12 cmH₂O)
• Emergency airway (direct visualization preferred)
• Cervical spine injury (uncontrolled neck movement with PDT)
• Children (anatomy too small; higher complication rate)

Technique (Ciaglia Blue Rhino Method)

Pre-Procedure Setup

1. Review: history, respiratory status, cross-sectional imaging (CT neck for vascular anatomy), labs (platelets, PT/PTT, BUN for uremia)
2. Ultrasound assessment of the neck recommended to map vasculature in the needle path
3. Staffing: anesthesiologist at head of bed to manage ETT and perform bronchoscopy; experienced nurse as circulator
4. Positioning: supine, shoulder roll placed to extend the neck and improve landmark identification; head of bed slightly elevated (reverse Trendelenburg or hip flexion) to reduce cervical venous pressure
5. Anesthesia: sedation + analgesia + short-acting paralysis to minimize coughing and movement
6. FiO₂ increased to 1.0 before starting

Step-by-Step Procedure (Ciaglia Blue Rhino)

• Air aspiration through the syringe (negative pressure)
• Bronchoscopic visualization of the needle tip inside the trachea (should be between the 10 and 2 o'clock positions on the anterior wall)

PDT procedural steps: (A) Introducer needle, (B) Guidewire in place, (C) 4Fr initial dilator, (D) Tapered Blue Rhino dilator. (Current Surgical Therapy 14e)

Alternative Percutaneous Techniques

Complications

Early Complications

Late Complications

The overall complication rate without bronchoscopic guidance is 16.8% vs. 8.3% with bronchoscopic guidance (Cummings Otolaryngology).

Advantages of PDT Over Surgical Tracheostomy

Key Points Summary

• PDT is the preferred method for elective tracheostomy in stable ICU patients
• The Ciaglia Blue Rhino single-tapered dilator over a Seldinger guidewire is the dominant technique
• Bronchoscopic guidance is strongly recommended (halves the complication rate)
• Ideal entry is between tracheal rings 1-2 or 2-3; above ring 3 to avoid tracheo-innominate fistula
• Pre-procedure ultrasound should be used to map vascular anatomy and guide needle placement - a 2025 meta-analysis (PMID 40281422) confirms ultrasound-guided PDT reduces complications versus landmark-guided technique
• Cuff pressure must be maintained < 25 mmHg to prevent ischemic necrosis and late stenosis/TIF
• After accidental decannulation in the first 7-10 days, always reintubate orally first - never blindly reinsert through an immature stoma

Preoperative Evaluation and Airway Management in TMJ Ankylosis

Background

Part 1: Preoperative Evaluation

History

• Duration and progression of mouth opening restriction
• Previous anaesthetic records - any previous intubation attempts, technique used, grade of laryngoscopy, complications. This is the single most important document.
• Prior surgeries or radiation to the head and neck (radiation causes fibrosis and further TMJ ankylosis, distorts tissue planes)
• Symptoms of obstructive sleep apnea (OSA) - chronic reduced mouth opening and micrognathia (especially in childhood-onset cases) predispose to OSA
• Stridor, positional breathing difficulty, snoring - suggest concurrent airway compromise
• History of neck pain, cervical spine disease, or instability (limits head positioning for laryngoscopy)

• Traumatic - condylar fracture, particularly common in children after unrecognised condylar injury
• Infective/inflammatory - otitis media (in children), suppurative arthritis, rheumatoid arthritis, ankylosing spondylitis
• Post-radiation fibrosis
• Congenital/syndromic - Pierre Robin sequence, Treacher Collins syndrome, Goldenhar syndrome (these patients have additional craniofacial anomalies compounding airway difficulty)
• Neonatal forceps injury

• Rheumatoid arthritis or ankylosing spondylitis: also affect cervical spine (atlanto-axial instability, limited neck extension) and arytenoid joints (cricoarytenoid arthritis - may cause fixed vocal cord, narrowed glottis)
• Nutritional status and general fitness (prolonged ankylosis in children leads to micrognathia, mandibular hypoplasia, and malocclusion)
• Aspiration history - chronic reduced oral intake, silent aspiration with recurrent chest infections

• Pain (acute trauma, infection) - may improve with analgesia and muscle relaxation under GA
• Trismus (muscle spasm from infection, trauma) - usually overcomes with muscle relaxation under GA
• True mechanical ankylosis - will NOT improve with GA or muscle relaxation; airway must be secured before induction

"If a patient cannot open their mouth during the preoperative evaluation, one must ascertain if the restriction to mouth opening results from pain, trismus, mechanical problem, or some combination of the three." - Barash's Clinical Anaesthesia

Physical Examination

• Stridor (inspiratory = supraglottic, biphasic = glottic/subglottic)
• Chest retraction, accessory muscle use
• Agitation, restlessness (hypoxia)
• Abnormal voice, dysphonia

Investigations

• Orthopantomogram (OPG/panoramic X-ray): Assessment of condylar morphology, bony ankylosis vs. fibrous, extent of joint involvement
• CT scan of TMJ/face/neck (with 3D reconstruction): Gold standard. Defines:
  • Nature and extent of ankylosis (unilateral vs. bilateral, fibrous vs. bony, extent of bony mass)
  • Mandibular hypoplasia, micrognathia
  • Relationship of bony mass to adjacent structures (middle cranial fossa, skull base)
  • Airway dimensions (oropharyngeal, hypopharyngeal, tracheal calibre)
  • Vascular anatomy of the neck (important if tracheostomy may be needed)
• MRI: Soft tissue detail - articular disc, surrounding muscles; particularly useful in fibrous ankylosis
• Cervical spine X-ray or CT: Especially if there is rheumatoid arthritis, ankylosing spondylitis, or a history suggesting instability (atlantoaxial subluxation)
• Lateral skull and chest X-ray: Chest for aspiration pneumonia, OSA-related changes

• Nasal passages for polyps, deviation, obstruction
• Pharyngeal anatomy and dimensions
• Glottic appearance - vocal cord movement, subglottic/glottic narrowing
• Confirms fiberoptic nasal intubation is likely to be feasible

Anaesthetic Risk Stratification

• Failed direct laryngoscopy (impossible to insert blade)
• Failed video laryngoscopy (cannot insert blade despite improved view)
• Potentially difficult mask ventilation (micrognathia, abnormal facial profile)
• Potentially difficult SGA placement (supraglottic airway devices need some mouth opening; most require ≥20 mm)
• Risk of "cannot intubate, cannot oxygenate" (CICO) scenario

Part 2: Methods of Airway Management for 5 mm Mouth Opening

Preparation Before Any Technique

• Senior/experienced anaesthesiologist
• ENT/maxillofacial surgeon scrubbed and available (for emergency surgical airway)
• Experienced anaesthesia nurse/assistant
• Neck prepped and draped for surgical airway at all times

• Flexible fiberoptic bronchoscope (video-capable preferred)
• Video laryngoscopes of various types
• Supraglottic airways (LMA, intubating LMA)
• Jet ventilation equipment / transtracheal jet ventilator
• Emergency surgical airway kit (cricothyrotomy, percutaneous or surgical tracheostomy)
• Nasal and oral airways of various sizes
• Endotracheal tubes (assorted sizes including microlaryngoscopy tubes; typically 6.0-7.0 for nasal approach in adults)
• Exhaled CO₂ detector

1. Awake Nasal Fiberoptic Intubation (FOI) - TECHNIQUE OF CHOICE

• Detailed pre-procedure explanation; patient cooperation is key to success
• Patient should understand each step and their role (keeping still, breathing, clearing secretions on request)

• Antisialagogue: Glycopyrrolate 0.2 mg IV, given 30 minutes before - reduces secretions, improves fiberoptic visibility. Preferred over atropine as it does not cross the blood-brain barrier and causes less tachycardia.
• Sedation (carefully titrated, minimal):
  • IV midazolam (1-2 mg titrated) - anxiolysis while maintaining cooperation
  • Dexmedetomidine infusion - excellent for awake intubation; provides sedation without respiratory depression, cooperative patient
  • Remifentanil infusion (caution - respiratory depression)
  • Ketamine (low dose) - preserves airway tone and respiratory drive
  • No sedation in patients with already compromised airway
• Supplemental oxygen via nasal cannula throughout (high flow; can use HFNO during procedure)

1. Patient sitting or semi-recumbent (head of bed 45°). Oxygen via nasal cannula.
2. Select the larger naris. Vasoconstrict with oxymetazoline or cocaine.
3. Lubricate a well-sized endotracheal tube (size 6.0-7.0 cuffed for adults; Ring-Adair-Elwyn (RAE) nasal tube or reinforced tube is used for oral surgery cases).
4. Load the ETT onto the fiberoptic bronchoscope (scope passes through the ETT lumen, ETT rides on scope).
5. Advance the bronchoscope along the nasal floor toward the occiput (not upward), past the inferior turbinate.
6. Navigate through the nasopharynx, identify the epiglottis and glottis.
7. Pass the scope through the vocal cords into the trachea - confirm by visualizing tracheal rings and carina.
8. Advance the ETT over the scope into the trachea, then withdraw the scope.
9. Confirm placement with CO₂ capnography, bilateral auscultation, and chest expansion.
10. Only after the airway is confirmed secured - induce general anaesthesia.

• Expert bronchoscopist
• Functioning, high-quality videobronchoscope
• Meticulous airway preparation (topical anaesthesia)
• Adequate but not excessive sedation
• Patient cooperation
• Overall complication rate is 16.8% without bronchoscopic guidance vs. 8.3% with

"Awake FOI is often an ideal procedure for producing an airway of adequate size and dealing with other medical conditions that make visualization of the glottis difficult, such as marked obesity, a supraglottic/glottic mass, supraglottic/glottic edema, or trismus." - Cummings Otolaryngology

2. Awake Video Laryngoscopy

• Requires some mouth opening; most video laryngoscopes (GlideScope, C-MAC, McGrath) require at least 15-20 mm
• With only 5 mm mouth opening, standard video laryngoscopes cannot be inserted
• Some narrow-profile blades (e.g., C-MAC Pocket Monitor with size 3 blade) may pass through smaller apertures, but 5 mm is generally prohibitive
• May be used as an adjunct after surgical treatment increases mouth opening, or combined with the retrograde technique

3. Retrograde Intubation

1. Identify and puncture the cricothyroid membrane with an 18-gauge needle, angled cephalad
2. Confirm intratracheal position by aspiration of air
3. Pass a J-tipped guidewire (or epidural catheter) through the needle, directed upward (cephalad) into the pharynx
4. Retrieve the wire from the nose or mouth using Magill forceps or blind digital retrieval
5. Pass the ETT over the wire (wire exits through the distal end or side port of the ETT) and advance into the trachea
6. Hold the wire taut at the CTM entry point and advance ETT until resistance is felt at the CTM - indicating the tube is in the correct position
7. Release the wire and advance the ETT further; confirm position

• The retrieved guidewire is threaded through the suction/working channel of the fiberoptic scope (distal to proximal)
• The FOB follows the wire as a guide, maintaining visualization throughout
• This allows the ETT to negotiate the vocal cord angle under direct vision
• Eliminates the blind advancement problem and reduces dislodgement risk

4. Blind Nasotracheal Intubation (BNTI)

• Patient positioned with head in neutral or slight extension ("sniffing")
• Lubricate and pass ETT along nasal floor, angling toward occiput
• As tube approaches glottis, maximum airflow is heard through the tube
• Advance swiftly at the start of inspiration; rotate medially 15-30° to enter trachea
• Depth: 28 cm at nares in men, 26 cm in women
• Confirm with CO₂, auscultation, fogging

5. Awake Surgical Tracheostomy Under Local Anaesthesia

• The anatomy is so distorted that fiberoptic access is impossible
• Severe bleeding/secretions obscure fiberoptic view
• Patient cannot cooperate with awake intubation
• Concurrent severe subglottic or glottic pathology precludes translaryngeal intubation
• In cases where surgery will be near the larynx or will displace the airway

6. Emergency Surgical Airway - Cricothyrotomy / Transtracheal Jet Ventilation (TTJV)

• 14-gauge cannula through CTM; connect to high-pressure oxygen source
• Provides oxygenation for 30-45 minutes (CO₂ accumulates)
• Bridging technique to definitive surgical airway

• Horizontal incision through CTM, dilation, insertion of cuffed tube (size 5-6)
• Rapid access; preferred over emergency tracheostomy
• Definitive technique; can be maintained until surgical tracheostomy is performed

Decision Algorithm for 5 mm Mouth Opening

Patient with 5 mm mouth opening (TMJ ankylosis) scheduled for surgery
                         |
        Preoperative assessment + MDT planning
                         |
              Is airway palpable/accessible?
                   /           \
                 YES             NO
                  |              |
     AWAKE NASAL FIBEROPTIC     Consider awake tracheostomy
     INTUBATION (1st choice)    under local anaesthesia
                  |
         Successful? → Induce GA → Surgery
                  |
           Failed (secretions/distorted anatomy)
                  |
     RETROGRADE INTUBATION (± combined FOB)
                  |
         Failed?
                  |
     AWAKE SURGICAL TRACHEOSTOMY UNDER LOCAL
                  |
         CICO emergency → Needle cricothyrotomy + TTJV
                  → Surgical cricothyrotomy

Special Considerations in TMJ Ankylosis Surgery

1. Intraoperative airway access: The surgeon will be working in and around the mandible and TMJ area. A nasal RAE tube or reinforced (armoured) nasotracheal tube is preferred to keep the oral cavity clear for the surgeon and to reduce accidental extubation during jaw manipulation.
2. Post-operative airway: After surgical release of ankylosis, the mouth opening may initially increase dramatically but post-operative oedema can reduce it again acutely. Plan for:
   • Keep intubated until oedema subsides
   • Extubation should be planned (ideally over an airway exchange catheter)
   • Post-operative tracheostomy may be appropriate in complex cases
3. Steroids and dexamethasone: Reduce oedema and improve post-operative airway
4. Obstructive sleep apnea co-management: If confirmed, plan CPAP post-operatively
5. Children with childhood-onset ankylosis: Mandibular growth arrest from ankylosis produces progressively worsening micrognathia. The difficulty compounds with age. These children may require distraction osteogenesis at the same sitting, further complicating anaesthetic planning.
6. Paediatric considerations (Cummings): Flexible fiberoptic bronchoscopes of appropriate paediatric size (2.5-3.5 mm outer diameter) are required; nasal RAE tubes sized age-appropriately; have LMA as ventilation rescue device.

Summary Table