Post-intubation hypoxia
Reviewed and revised 26 September 2015
Overview
Post-intubation hypoxia can be rapidly fatal without early intervention, which requires a structured approach to concurrently identifying and treating the underlying cause
Causes
The immediate life threats can be summarized as “DOPES”:
- Displacement of the endotracheal tube (ETT)
- Obstruction of the ETT
- Patient — especially pneumothorax; also: pulmonary embolism, pulmonary edema, collapse, bronchospasm
- Equipment — ventilator problems
- ‘Stacked breaths’ — a reminder about bronchospasm and ventilator settings.
Structured approach
- Disconnect the ventilator and administer high-flow 100% oxygen (FiO2 1.0) using a bag-valve-mask.
- Disconnection allows the release of trapped gas in the patient with severe bronchospasm — these patients usually have evidence of bronchospasm and/ or hypotension in addition to hypoxia.
- Also, if the patient is easy to ventilate and re-oxygenate, then the problem probably lies with the ventilator or the circuit.
- In a ventilated patient that has a problem always think: man versus machine.
- Assess the patient using the MASH approach before attempting to diagnose the problem:
- Movement of the chest during ventilation —
is it absent or is movement only on one side? Is the chest hyper-expanded? - Arterial saturation (SaO2) and PaO2 —
obtain an ABG sample - Skin colour of the patient (is he turning blue or pinking up?) —
the SO2 monitor lags behind the true oxygen saturation of the patient. - Hemodynamic stability
- Movement of the chest during ventilation —
- If the patient is difficult to manually ventilate, determine if the problem lies with the endotracheal tube or with the patient.
- If there is little chest movement, a patient problem is still possible, but a problem with the ETT needs to be be ruled out urgently:
- check ETCO2 to ensure the ETT is not in the esophagus and is patent.
- pass a suction catheter and/ or a bougie to ensure the ETT is not obstructed.
- check the placement of the tube visually — preferably by bronchoscopy, or alternative by by laryngoscopy from the top end (although this is far from 100% reliable).
- consider a CXR to check ETT position if hypoxemia is not critical, especially if endobronchial intubation is suspected
- If in doubt, and the hypoxia has not been rapidly resolved, take the tube out… and replace it.
- If there is reasonable chest movement, a patient problem is most likely. Perform a focused exam and urgently seek and treat the following life-threats:
- pneumothorax (look for asymmetrical chest movement)
- lung collapse (look for asymmetrical chest movement)
- pulmonary edema
- bronchospasm (chest wall movement may be minimal — look for hyper-expansion)
- pulmonary embolus
- If the bag is easy to compress during manual ventilation, but there is little or no chest movement suspect either:
- a circuit leak (e.g. cuff leak, disconnection, or a hole in the circuit), OR
- dislodgement of the endotracheal tube — you may be ventilating the oropharynx or the stomach
- If the patient is easy to ventilate with the bag and the hypoxemia rapidly resolves
- Find out what happened just before the desaturation:
- had suctioning been performed? (in some settings the loss of PEEP during disconnection of the circuit may lead to derecruitment and atelectasis, result in desaturation)
- had there been a disconnection of the ventilator/circuit?
- Otherwise, there may be a problem with the ventilator settings or there was an equipment failure.
- check ventilator settings
- trouble-shoot equipment failure
- Find out what happened just before the desaturation:
Acute Respiratory distress syndrome (ARDS)
ARDS patients are typically ventilated with a protective lung ventilation strategy +/- an open lung approach. In cases of refractory hypoxaemia there are numerous strategies for improving oxygenation in ARDS. These topics are covered in other sections of the CCC, see the CCC ventilation series below.
References and Links
CCC Airway Series
Emergencies: Can’t Intubate, Can’t Intubate, Can’t Oxygenate (CICO), Laryngospasm, Surgical Cricothyroidotomy
Conditions: Airway Obstruction, Airway in C-Spine Injury, Airway mgmt in major trauma, Airway in Maxillofacial Trauma, Airway in Neck Trauma, Angioedema, Coroner’s Clot, Intubation of the GI Bleeder, Intubation in GIH, Intubation, hypotension and shock, Peri-intubation life threats, Stridor, Post-Extubation Stridor, Tracheo-esophageal fistula, Trismus and Restricted Mouth Opening
Pre-Intubation: Airway Assessment, Apnoeic Oxygenation, Pre-oxygenation
Paediatric: Paediatric Airway, Paeds Anaesthetic Equipment, Upper airway obstruction in a child
Airway adjuncts: Intubating LMA, Laryngeal Mask Airway (LMA)
Intubation Aids: Bougie, Stylet, Airway Exchange Catheter
Intubation Pharmacology: Paralytics for intubation of the critically ill, Pre-treatment for RSI
Laryngoscopy: Bimanual laryngoscopy, Direct Laryngoscopy, Suction Assisted Laryngoscopy Airway Decontamination (SALAD), Three Axis Alignment vs Two Curve Theory, Video Laryngoscopy, Video Laryngoscopy vs. Direct
Intubation: Adverse effects of endotracheal intubation, Awake Intubation, Blind Digital Intubation, Cricoid Pressure, Delayed sequence intubation (DSI), Nasal intubation, Pre-hospital RSI, Rapid Sequence Intubation (RSI), RSI and PALM
Post-intubation: ETT Cuff Leak, Hypoxia, Post-intubation Care, Unplanned Extubation
Tracheostomy: Anatomy, Assessment of swallow, Bleeding trache, Complications, Insertion, Insertion timing, Literature summary, Perc. Trache, Perc. vs surgical trache, Respiratory distress in a trache patient, Trache Adv. and Disadv., Trache summary
Misc: Airway literature summaries, Bronchoscopic Anatomy, Cuff Leak Test, Difficult airway algorithms, Phases of Swallowing
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
LITFL
- Pulmonary Puzzle 012 — Man versus Machine
FOAM and web resources
- ICU Web — Trouble-shooting mechanical ventilation; Asthma
- EMCrit — Podcast 16 – Coding Asthmatic, DOPES, & Finger Thoracostomy
- EMCrit — Origins of the DOPES mnemonic (2011)
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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