Peri-intubation life threats
OVERVIEW
- VAPOURS is a mnemonic that can be used to ensure that life threats during the emergency peri-intubation period are addressed (a Levitanism, but with anglicised spelling!)
- In emergency situations, although A for airway comes at the start of the alphabet (ABC approach), definitive management does not necessarily need to be instituted immediately
- The ABC (or cABC) approach is useful as a cognitive aid to the systematic assessment of potential life-threats and what to treat, however, interventions should be ‘resequenced’ to allow pathophysiology to be optimised prior to definitive interventions (where possible) so that adverse effects will not leave the patient compromised.
- Useful mantras to consider:
- Think of RSI as ‘resuscitation sequenced intubation’ (another Levitanism) rather than ‘rapid sequence intubation’
- ‘Optimise (and customise) before you compromise’
- ‘Oxygenate (and ventilate) before you intubate’
PHASES OF INTUBATION
Pre-induction
- preoxygenation fills up lungs
- sympathetic outflow due to pain and compensatory mechanisms (peripheral vasoconstriction)
Induction
- negative inotropy
- vasodilation
- decreased level of consciousness
Laryngoscopic/ intubation stimulus
- typically pressor effect due to sympathetic outflow
- may be blunted in coma
- typically persists in traumatic brain injury (TBI), for instance, when there can be wild swings in blood pressure
- may be blunted by (pre)induction agents (e.g. fentanyl, lignociane)
Effect of apnea
- oxygen consumption
- hypercapnea
- Respiratory acidosis
Post-induction/ intubation phase
- persisting effect of induction agents
- positive pressure ventilation, in certain circumstances, can contribute to clinically significant:
- Decrease in venous return
- Increase in pulmonary artery pressure and afterload on the right ventricle
- Dynamic hyperinflation
EXPLANATION OF “VAPOURS”
VAPOURS is a mnemonic categorising the types of (often inter-related) life threats that occur peri-intubation and the measures that can be taken during the:
- Pre-induction phase
- Post-induction phase (“apnea phase”)
- Post-intubation phase
Ventilation
- match patient’s minute ventilation if metabolic acidaemia (see below)
- correct severe hypoventilation prior to intubation to allow preoxygenation
- correct respiratory acidaemia and prevent excess cerebral vasodilation in at-risk patients
- ventilate gently to avoid respiratory alkalosis, gastric distention and baro/volutrauma
Acidaemia
- correct acidaemia and avoid respiratory acidosis (e.g. ventilate during “apnoie phase”)
Pressures
- A – alveolar
- protective lung ventilation with open lung approach to prevent VALI and avoid hypoxaemia
- B – brain
- in the setting of TBI or raised intracranial pressure, avoid excessive PEEP to prevent further increases in ICP and maintain adequate MAP to maintain CPP
- C – circulatory pressures (systemic and pulmonary)
- avoid systemic hypotension (start inopressor agents prior to intubation in at-risk patients
- avoid exacerbating pulmonary hypertension/ right heart failure in ‘at risk’ patients (e.g. avoid hypoxia, avoid acidaemia/ CO2 rise, avoid excessive PEEP and PPV)
- D – dynamic hyperinflation
- avoid by providing an obstructive airways apporach to ventilation; disconnect from ventilator/ BVM if hypotension
- E – (o)esophageal/ gastric pressures
- aim to ventilate with positive airway pressure (PAP) <15 cmH20 prior to intubation to prevent gastric distention
- some patients may benefit from a nasogastric tube (NGT) to decompress the stomach prior to or immediately after intubation (e.g. small children, small bowel obstruction, etc), however, this must be weighed against the risk of delay, distraction, discomfort, and deleterious adverse effects.
Oxygenation
- optimise preoxygenation, apnoeic oxygenation and post-intubation oxygenation (i.e. peroxygenation, the term used by the Difficult Airway Society (DAS) to describe all three phases)
- Consider ventilation during the “apnoeic phase” (weighed against the risk of regurgitation and aspiration), especially in patients who cannot be adequately preoxygenation due to “shunt” physiology
Underlying disease
- seek and treat underlying disease and complications prior to intubation if it addresses an immediate life-threat or makes airway management safer
Regurgitation/ Fluids
- perform “rapid sequence intubation” if high risk of aspiration and no other life threats
- control upper airway bleeding, suction secretions, consider prokinetics and/or NGT to reduce risk of regurgitation
Shock Index
- shock index >1 predicts high risk of life-threatening hypotension
- Shock index = heart rate (/min)/ systolic blood pressure (mmHg)
- address by treating the underlying cause, appropriate fluid resuscitation and use of inotropes/ vasopressors
Resources 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
Journal articles
- Green RS, Fergusson DA, Turgeon AF, et al. Resuscitation Prior to Emergency Endotracheal Intubation: Results of a National Survey. West J Emerg Med. 2016;17(5):542-8. [article]
- Jaber S, Jung B, Corne P, et al. An intervention to decrease complications related to endotracheal intubation in the intensive care unit: a prospective, multiple-center study. Intensive Care Med. 2010;36(2):248-55. [pubmed]
FOAM and web resources
- ACEP Now — Timing Resuscitation Sequence Intubation for Critically Ill Patients by Richard Levitan (2015)
- St Mungos — Resuscitation Sequence Intubation
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC