3“He sat in bed supporting himself with stiffened arms: his head was thrown forwards, and he had the distressed anxiety so characteristic of impending suffocation …. His inspirations were crowing and laboured, and there was a very frequent forced attempt to swallow, attended by extreme pain, … He spoke in a muffled whisper, and confined his answers, when possible, to monosyllables, or substituted signs by head or hand. …”Sir William MacEwenBMJ July pp 123
6Laryngeal Trauma: incidence Rare – Why?under reported - paucity of peer reviewed data -American Association Oral Maxillofacial Surgeons 2006:Current Opinion Otolaryngology (6):patients die before reaching hospital – not reported in datalarynx well protected & flexiblemandible - superiorly; sternocleidomastoids – laterally; clavicles – inferiorly.6
7Laryngeal Trauma: Diagnosis DIAGNOSIS OF SUSPICIONlaryngeal trauma NEEDS to be excludeddiagnosis may not be obvious in a patient with an uncompromised airwaysymptoms & signs unrelated to degree of traumathis may also be reason for under reportingOnce diagnosed the extent of injury must be defined before any attempt at intubationETT across injured larynx can convert mucosal laceration to a more complex problemETT can cause complete laryngo-tracheal separation7
8Laryngeal Trauma: Morbidity/mortality 0-18%J Trauma (1):87-93Delay in diagnosis increases morbidity & mortalitypharyngeal, oesophageal & vessel injury must be excludedConcurrent occult oesophageal injury significantly contributes to morbidity & mortalityevaluation of oesophagus mandatory - NB before placement N/G tube8
12Laryngeal trauma: History may give some idea of injury Complete L-T separation associated with:hyperextension injuries: avulsion of larynx – tearing of fibrous ring between CC & 1st tracheal ringstrangulationrarely associated with blunt traumaASSOCIATED WITH # CRICOID CARTILAGE# Thyroid Cartilage:neck hyperflexionKnife or Gunshot woundsevaluate the oesophagus
13Multiple threats to airway: Direct penetrationDistorted tissue planesHaematomaOedemaExcessive blood & secretions
14Multiple threats to airway: ..2 IPPV & coughing:worsen air leakss/c emphysemaCricoid pressure:lead to laryngo-tracheal separation
22Fractured Larynx: Management Tracheostomy under LA vs GAManagement is NOT A LEARNING EXPERIENCEHELIOXFOB & Cricothyroidotomy may not be appropriateIntubation may not be appropriatemay cause complete separation
23WHY HELIOX? Less dense – work of breathing less. Decrease amount of subcutaneous emphysema
24Helium - Upper airway obstruction “When it is available an even better effect can be expected from inhalation of 79% Helium with 21% Oxygen”Wylie Churchill Davidson pp 382
26Turbulent flow Turbulent flow F ~ P1/2/Lρ1/2 Density importantTurbulent flowF ~ P1/2/Lρ1/2F = flow; P = pressure;ρ = density; L = length.(Radius important but not expressible as a power of the diameter - as radius decreases flow decreases also)Turbulent flow: flow greater with Heliox than air or O2
27Relationship between pressure and flow during turbulent flow HelioxEven if flow is turbulent there is less work of breathing and greater flow with given pressure changeO2Comparison between Heliox (black)& air or O2 (yellow)
28Why Helium? Hylegaard et al O2 breathing initial bubble growthO2 > He solubility in fatbuild up O2 around bubble in tissueHelium breathing bubble constantly shrunk
29Helium mixtures: Physics /Gas flux GAS FLUX = diffusion x solubility coefficientHe>N2 diffusibility (smaller atomic wt)He<N2 solubility in fatty tissue, water & bloodHe<O2 solubility in fatty tissuetherefore:-N2 or O2 flux into fatty tissue > He fluxHENSE ANY AIR POCKETS WILL SHRINK.
30WHY HELIOX?HELIOX WILL GAIN PATIENT’S CONFIDENCE AND MAKE BREATHING EASIERAND MAY DECREASE THE AMOUNT OF S/C EMPHYSEMA.
325 Case Histories Maybe others – but not recognised. trauma patients on ICU ventilator – laryngeal oedema when extubated a couple of days later – ‘floppy epiglottis’ on intubation1. Walker in mountainshoarse voice in GP’s surgeryGA - laryngoscopy – unable to identify any structures, unable to intubate (fortunately!!)obstructed during tracheostomy with retractors2. Motorcyclist on farmer’s propertyintubated at scene
335 Case Histories 3. MVA – car rolled. hanged by seat belt upside downcomplete tracheal/laryngeal separationpartial obstruction with palpation of neck - GA4. Motorcyclist – MVA – Modbury Hospitalgaseous inductioncomplete obstruction during tracheostomy – retractors again5. And ….
37SURGICAL TRACHEOSTOMY Head extended exposing the neck.Neck palpated. LA injected.May not be able to extend the head.Palpation of structures maypress on trachea & cause anxiety.LA stings – may increase anxiety.Horizontal 6 cm incision to anteriorborders sternocleidomastoid muscles.Skin, subcut tissue, platysma to deep fascia.Veins may be enlarged due toinspiratory/expiratory pressures
38Self retaining retractor placed, dissection to strap muscles Strap muscles divided & retracted.Langerbech retractors placed.Retractor placement important – to much pressurecan obstruct airway.
39Trachea is exposed Thyroid isthmus exposed, clamped , divided and ligated, rotated externally & sutured.Retractor placement again important – to much pressurecan obstruct airway.Trachea is exposed
40Tracheal incision sited over 2nd & 3rd or 3rd & 4th tracheal rings. Tracheostomy tube insertedPlacement of tube may causesome distress
41Summary: Rare – diagnosis of suspicion Mortality ~20% increases if unrecognisedConcurrent oesophageal injury increases morbidity & mortalityneeds to be excludedInability to lie supine – indication immediate tracheostomy
42Summary: ..2 Consider Heliox if available Avoid coughing – may make s/c emphysema worse and airway impossibleAwake tracheostomy vs SV GA?careful palpationcare with retractors
433rd SIG Airway Meeting Lorne March 9-11 2012 “Everything airways including problems outside the OT”