LMH ER ROUNDS OCTOBER 27, 2015 PREPARED BY SHANE BARCLAY Airway 2: Infraglotic and Difficult Airways

Objectives 1.Examine pros and cons of direct versus video laryngoscopy 2.Review the steps on ET Tube intubation. 3. Surgical Airway - Cricothyroidotomy

What is the ‘difficult airway’? This presentation will not discuss the characteristics of what a ‘difficult airway’ is per se. This is covered in such areas as ‘up to date’ etc. In the emergency setting every airway should be considered ‘difficult’ until proven otherwise (i.e. successfully intubated). Because all airways should be considered difficult, the biggest advantage you can have is having a PLAN. In particular a back up plan which can include a rescue airway (LMA, Kingtube) and the ultimate backup plan, doing a Cricothyrotomy.

Rapid Sequence Intubation (RSI) RSI is one term used in Emergency Medicine to indicate a technique of controlling the airway by inducing unresponsiveness (via induction agents) and muscle relaxation/paralysis (via neuromuscular blocking agents), then intubating the patient. There are other ‘modified’ RSI protocols which endeavor to help maintain oxygenation, prevent respiratory acidosis etc. but these are often at the expense of increased risk of aspiration. The biggest ‘risk’ for RSI is that once you have given the paralytic, the patients life “is in your hands”. You must be able to either intubate or at the least ventilate the patient.

Review of Indications for Intubation 1. Airway protection and patency 2. Respiratory failure (either hypercapnia and hypoxia), secretion management. 3. Minimize oxygen consumption and increase oxygen delivery (ie sepsis) 4. Unresponsiveness to pain treatment, terminate seizure, prevent secondary brain injury. 5. Temperature control (serotonin syndrome) 6. Safety and comfort of patient (psychotic patient in transport, procedures etc)

What can make for a ‘difficult airway’? Dynamically deteriorating clinical situation, i.e., there is a real “need for speed” Non-cooperative patient Respiratory and ventilatory compromise Impaired oxygenation Full stomach (increased risk of regurgitation, vomiting, aspiration) Extremely short safe apnea times Secretions, blood, vomitus, and distorted anatomy

Steps for RSI – “9Ps” 1.Plan 2.Preparation (drugs, people, equipment..) 3.Protect the cervical spine 4.Positioning (sniff and head up) 5.Pre-oxygenate 6.Pre-treatment (optional i.e. atropine, lidocaine, fentanyl) 7.Paralysis and Induction 8.Placement of proof 9.Post intubation management

Roles and persons for RSI In an ‘ideal’ setting: 1.Airway proceduralist 2.Airway assistant 3.Medication administrator 4.Person to perform crioid pressure if necessary 5.Scribe The Team Leader may perform one of these roles, but ideally should be separate and in a ‘stand alone’ role.

Equipment 1. Suction. Place between mattress and bed. 2. Oxygen. Non rebreather (NRBM) or Bag Mask (BVM) with 15 lpm O2. Can also use nasal cannula during intubation – high flow lpm 3. Airway 7.5 ETT for most adults, 7.0 for smaller females. 8.0 for large males or if possible for asthmatics. Test balloon with 10 cc air with syringe. Leave syringe attached to ETT. Stylet, place in ETT. Or Bougie Blade – Mac 3 or 4 for adults. Same sizing for McGrath Video scope. Handle – attach blade and make sure light works. Backup – ALWAYS have an LMA and surgical Cric kit available.

Equipment 4. Pre-oxygenate 15 lmp with NRBV or flow from BVM. If patient not breathing, ensure BMV vents at per minute with appropriate volume. 5. Monitoring equipment. Cardiac monitor (best if hooked up to defib pads on the Lifepac) Pulse oximeter BP cuff Have EtCO2 on BVM or ready to hook up to ETT. 6. Medications. Have induction and paralytics drawn up.

‘Quick Review’ of Induction Agents Ketamine mg/kg IBW Fentanyl 2-10 mcg/kg TBW Midazolam mg/kg TBW Propofol mg/kg IBW + (0.4 x TBW) (others simply use 1.5 mg/kg x TBW as the general guide)

‘Quick Review’ of Induction Agents Ketamine Dose: 1.5 – 2 mg/kg IV (4 – 5 mg/kg IM) Onset: sec Duration: min Use: any RSI, especially if hemodynamically unstable (OK in TBI, does not increase ICP despite traditional dogma) or if reactive airways disease (causes bronchodilation) Drawbacks: increased secretions, caution in cardiovascular disease (hypertension, tachycardia), laryngospasm (rare)

‘Quick Review’ of Induction Agents Propofol Propofol mg/kg IBW + (0.4 x TBW) (others simply use mg/kg x TBW as the general guide) Onset: seconds Duration: 5 – 10 minutes Use: Hemodynamically stable patients, reactive airways disease, status epilepticus Drawbacks: hypotension, myocardial depression, reduced cerebral perfusion, pain on injection, variable response, very short acting

‘Quick Review’ of Induction Agents Midazolam Dose: 0.3mg/kg IV TBW Onset: sec Duration: min Use: not usually recommended for RSI anymore, some practitioners use low doses of midazolam and fentanyl for RSI of shocked patients. Drawbacks: respiratory depression, apnea, hypotension, paradoxical agitation, slow onset, variable response

‘Quick Review’ of Induction Agents Fentanyl Dose IV 2-10 mcg/kg TBW Onset: <60 seconds (maximal at ~5 min) Duration: dose dependent (30 minutes for 1-2 mcg/kg, 6h for 100 mcg/kg) Use: may be used in a low dose as a sympatholytic premedication (e.g. TBI, SAH, vascular emergencies); may be used in a ’modified’ RSI approach in low doses or titrated to effect in cardiogenic shock and other hemodynamically unstable conditions Drawbacks: respiratory depression, apnea, hypotension, slow onset, nausea and vomiting, muscular rigidity in high induction doses, bradycardia, tissue saturation at high doses or if given rapidly.

‘Quick Review’ of Neuromuscular Blocking Agents Succinylcholine 1-2 mg/kg TBW Rocuronium mg/kg IBW

‘Quick Review’ of Neuromuscular Blocking Agents Succinylcholine Dose: 1.5 mg/kg IV (2 mg/kg IV if myasthenia gravis) and 4 mg/kg IM (in extremis) Onset: seconds Duration: 6-10 minutes Use: widely used unless contraindicated; ideal if need to extubate rapidly following an elective procedure or to assess neurology in an intubated patient Drawbacks: numerous contra-indications (hyperkalemia, malignant hyperthermia, >5d after burns/ crush injury/ neuromuscular disorder), bradycardia (esp after repeat doses), hyperkalemia, fasciculations, elevated intra-ocular pressure(?), will not wear off fast enough to prevent harm in ‘Can’t intubate, can’t ventilate’ (CICV) situations

‘Quick Review’ of Neuromuscular Blocking Agents Rocuronium Dose: 1.2 mg/kg IV IBW Onset: 60 seconds Use: can be used for any RSI unless contra-indication or require rapid recovery for extubation after elective procedure or neurological assessment; ensures persistent ideal conditions in CICV situation (i.e. immobile patient for cricothyroidotomy) Drawbacks: allergy (Rare)

RSI Steps 1. Check neck for potential cric, have cric kit and LMA available 2. Positioning – sniffing position, ideally head up 3. Preoxygenation – 100% NRB 15 lpm x 3 minutes or flow via BVM 4. Attach in line EtCO2 monitor to BVM 5. Pick ET tube. Check balloon with 10 cc air, leave syringe attached. Place stylet or have bougie handy. 6. ‘Lube the tube’ – put small amount of sterile lube jelly on ETT tip 7. Choice of laryngoscope. Check bulb working. 8. Suction – turn on, place handle under right shoulder of patient or under pillow.

RSI Steps 9. Have epinephrine push dose on hand – 5-10 mcg/kg IV 10. Induction agents – Ketamine 1.5 mg/kg or Propofol 1.5 – 2.0 mg/kg (or Midazolam 0.3 mg/kg TBW) 11. Neuromuscular blocking agents – Succinylcholine 1-2 mg/kg TBW 12. Cricoid pressure – BURP 13. Intubate – place ETT 23 cm to lips for males, 21 cm to lips for females. Inflate balloon. 14. Confirm – watch for chest rise, listen to chest, check EtCO2 15. Order CXR to confirm ETT depth 16. Post intubation medications – Fentanyl or morphine infusion. +/- sedation

RSI Steps 17. Ventilator settings. (may vary depending on clinical scenario) Mode: AC FiO2 100% RR 14 Tidal Volume 6-8 cc/kg IBW PEEP? 5 or as needed. 18. ABG after minutes. Consult ARDSnet chart.

Cricothyrotomy This is your final back up. You should know how to do one! Although there are various techniques for doing ‘crics’ the one being advocated most recently is the ‘bougie assisted Cricothyrotomy’. In Lady Minto Hospital we have the ‘needle cric’ set which use an ‘over the needle’ technique. The bougie assist technique has been shown to be vastly quicker (average 60 seconds vs seconds) and more accurate than the needle cric.

Cricothyrotomy

Landmarks for the cricothyroid membrane: Feel for the laryngeal prominence. The cricothyroid membrane will be approximately one fingerbreadth below this. Alternatively, place four fingers longitudinally across the neck with the 5 th finger on the sternal notch. The cricothyroid membrane ‘should’ be right below your index finger.

Cric “landmarks schmanmarks” Acad Emerg Med 2015 August Be Ready to Extend the Incision Beyond Landmarks When Performing a Cric! Compared with ultrasound, three classic landmark techniques were inaccurate for identification of the cricothyroid membrane. While there are a number of landmark techniques for identification of the cricothyroid membrane, their accuracy is unknown. This study compared three techniques (general palpation, four-finger, and neck crease) to each other and to ultrasound (the reference standard). Each of 50 adult emergency department patients awaiting further care was assessed by a convenience sample of three emergency physicians who were randomly assigned to one of the three techniques. An expert then used ultrasound to identify the cricothyroid membrane in each patient. Compared to ultrasound, the general palpation, neck crease, and four-finger techniques were accurate 62%, 50%, and 46% of the time, respectively.

Cricothyrotomy Knife-finger-bougie approach Equipment scalpel blade (e.g. size 10)(some authors prefer an 11) artery forceps - optional bougie size 6.00 or 6.5 ETT (or tracheostomy tube) Once decision made to proceed with Emergency Surgical Airway (ESA) extend neck in supine position to make anatomy more accessible by palpation (aka the ‘laryngeal handshake’) +/- ultrasound (if time and available); note that airway has priority over suspected c-spine injury Stabilise the thyroid cartilage with the non-dominant hand Dominant hand holds scalpel and rests on the patients sternum for stability and support

Cricothyrotomy Make a 4 cm vertical incision through skin over cricothyroid membrane (in the midline). You may need to extend from mandible to sternum if not palpable anatomy. (step may not be necessary if easily palpable anatomy – can go straight to the horizontal incision) Once skin incised, palpate cricothyroid membrane position and blunt dissect with fingers (some prefer forceps) through subcutaneous tissue until the membrane is readily identifiable. Ignore bleeding until airway is secure (ETT placement usually has a tamponade effect)

Cricothyrotomy Make a 1 cm horizontal incision through lower edge of membrane, (cricothyroid vessels lie in the superior segment). Drag scalpel blade from one side to the other then turn knife through 180 degrees and extend to the other side (some prefer to extend the membrane with forceps). The cricothyroid membrane is bound by a ‘cartilaginous cage’ so resistance will be felt at the margins of the membrane when the scalpel blade abuts cartilage. Dilate with gloved little finger and palpate tracheal lumen, ideally identifying the cartilage of the posterior wall of the trachea/cricoid ring Pass bougie alongside little finger into trachea Confirm bougie position with finger, ensuring it passes through membrane

Cricothyrotomy Bougie usually holds up at carina <10cm from the skin (may feel tracheal rings as the bougie advances), do not force if it hold up as you may perforate carina Pass ETT over bougie and intubate trachea. Ensure the ETT balloon is fully deflated and twist ETT as it passes the skin (hold up here is common). Only advance the ETT until the balloon is within the airway and no longer visible (if advanced further then endobronchial intubation is likely). Ensure ETT is held secure while bougie is removed and ETT is connected to BVM Confirm ETT placement with ETCO2 (also adjunctive measures: auscultation, bilateral rise and fall of chest, fogging of tube and subsequent CXR)

Cricothyrotomy On the web page lmher.com/airway-2 there are two videos demonstrating Cricothyrotomy.