Burns, Oxygenation and Ventilation
OVERVIEW
Burns can affect 4 anatomic areas of the respiratory tract:
- Supraglottal
- tracheobronchial
- pulmonary parenchymal
- chest/abdominal wall
There may also be
- associated injuries (e.g. blast)
- exacerbation of underlying illness
- complications of burns and therapies (e.g. anaphylaxis, fluid overload, VALI, VAP)
- systemic toxicity (e.g CO, cyanide)
EFFECTS
Supraglottal
- Loss of airway patency due to mucosal oedema
- Loss of airway reflexes due to coma (e.g. blast Traumatic brain injury, intoxications such as carbon monoxide,)
Tracheobronchial
- Bronchospasm resulting from inhaled irritants
- Mucosal oedema and endobronchial sloughing causing small airway occlusion, leading to intrapulmonary shunting
Pulmonary Parenchymal
- Pulmonary (alveolar) oedema and collapse leading to decreased compliance, and further intrapulmonary shunting
- Loss of tracheobronchial epithelium and airway ciliary clearance contributing to tracheobronchitis and pneumonia
- Barotrauma, ARDS, pleural effusions, VAP, TRALI and tracheobronchitis may all result from therapies given
Mechanical
- Circumferential full thickness burns of the chest and abdomen may cause reduced static compliance resulting in restrictive ventilator defect
- made worse by large volumes of oedema with fluid resuscitation and capillary leak
Other
- Toxic inhalation of carbon monoxide (CO) resulting in a left shift of the ODC and oxygen transport capacity (Carboxy Hb) and decreased cellular oxidative processes
- Other toxic gases NH3, HCL – pulmonary oedema,mucosal irritation and ALI
- CN- poisoning, cellular hypoxia
- Increased metabolic requirements may overwhelm a respiratory system already impaired by all the above
MANAGEMENT
- Prepare for difficult airway, intubate early, get help, consider AFOI or intubation in OT with ENT on standby
- FiO2 to keep SpO2 88-94% with titrated PEEP
- Protective lung ventilation with tidal volume 6 mL/kg PBW and plateau pressures <30
- Bronchoscopy to assess injuries early
- FiO2 1.0 +/- hypbaric if CO poisoning, treat cyanide poisoning (hydroxocobalimin, sodium thiosulfate)
- escharotomy as needed
- Treat exacerbation of underlying illnesses, associated injuries and complications of therapy
References and Links
CCC Ventilation Series
Modes: Adaptive Support Ventilation (ASV), Airway Pressure Release Ventilation (APRV), High Frequency Oscillation Ventilation (HFOV), High Frequency Ventilation (HFV), Modes of ventilation, Non-Invasive Ventilation (NIV), Spontaneous breathing and mechanical ventilation
Conditions: Acute Respiratory Distress Syndrome (ARDS), ARDS Definitions, ARDS Literature Summaries, Asthma, Bronchopleural Fistula, Burns, Oxygenation and Ventilation, COPD, Haemoptysis, Improving Oxygenation in ARDS, NIV and Asthma, NIV and the Critically Ill, Ventilator Induced Lung Injury (VILI), Volutrauma
Strategies: ARDSnet Ventilation, Open lung approach, Oxygen Saturation Targets, Protective Lung Ventilation, Recruitment manoeuvres in ARDS, Sedation pauses, Selective Lung Ventilation
Adjuncts: Adjunctive Respiratory Therapies, ECMO Overview, Heliox, Neuromuscular blockade in ARDS, Prone positioning and Mechanical Ventilation
Situations: Cuff leak, Difficulty weaning, High Airway Pressures, Post-Intubation Care, Post-intubation hypoxia
Troubleshooting: Autotriggering of the ventilator, High airway and alveolar pressures / pressure alarm, Ventilator Dyssynchrony
Investigation / Indices: A-a gradient, Capnography and waveforms, Electrical Impedance Tomography, Indices that predict difficult weaning, PaO2/FiO2 Ratio (PF), Transpulmonary pressure (TPP)
Extubation: Cuff Leak Test, Extubation Assessment in ED, Extubation Assessment in ICU, NIV for weaning, Post-Extubation Stridor, Spontaneous breathing trial, Unplanned extubation, Weaning from mechanical ventilation
Core Knowledge: Basics of Mechanical Ventilation, Driving Pressure, Dynamic pressure-volume loops, flow versus time graph, flow volume loops, Indications and complications, Intrinsic PEEP (autoPEEP), Oxygen Haemoglobin Dissociation Curve, Positive End Expiratory Pressure (PEEP), Pulmonary Mechanics, Pressure Vs Time Graph, Pressure vs Volume Loop, Setting up a ventilator, Ventilator waveform analysis, Volume vs time graph
Equipment: Capnography and CO2 Detector, Heat and Moisture Exchanger (HME), Ideal helicopter ventilator, Wet Circuit
MISC: Sedation in ICU, Ventilation literature summaries
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
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