May 23, 2019

Background: Predicting a challenging airway is important to assist in the most optimal approach to airway management during RSI.  Two such tools include the Mallampati and LEMON scores and were derived in the pre-operative setting. Major limitations of these scores include the requirement of patients to be awake and cooperative and they don’t incorporate physiologic factors into them. The HEAVEN criteria is a recently developed tool thought to be more relevant and feasible for emergency airway assessment.  Each letter of HEAVEN stands for the difficult airway characteristic:
  • Hypoxemia - ≤93% at the time of initial laryngoscopy
  • Extremes of size – Pediatric patient ≤8 years of age or clinical obesity
  • Anatomic challenge – any structural abnormality that is anticipated to limit laryngoscopic view
  • Vomit/blood/fluid – Clinically significant fluid noted in the pharynx or hypopharynx prior to laryngoscopy
  • Exsanguination – Suspected anemia raising concerns about limiting safe apnea times
  • Neck mobility issues – Limited cervical range of motion

January 31, 2018

Background: Predicting an anatomically and/or physiologically challenging airway is not a straightforward task by any stretch of the imagination.  There are some existing difficult-airway prediction tools available (i.e. LEMON = Look externally, Evaluate 3-3-2 rule, Mallampati score, Obstruction, Neck mobility), but many of them were derived in an elective surgery setting and may not be as applicable to emergency airway management.  Additionally, these prediction models only focus on anatomical challenges and ignore physiologic ones. Several components of the LEMON approach require an awake, cooperative patient. The authors of this paper derived a tool, called the HEAVEN criteria (Hypoxemia, Extremes of size, Anatomic abnormalities, Vomit/blood/fluid, Exsanguination, Neck mobility issues) to address this clinical need.