Unexpected difficult airway exposes the patient to serious morbidity and even mortality.
Obstetrics airway carries the risk of complications due to physiological changes. The
airway shows more restriction and changes in preeclamptic patients and peripartum
periods. A study reported one incidence of difficult intubation in obstetrics in 20
cases. Inadequate airway management leads to failure in ventilation and oxygenation of
the critically ill mother and her fetus.
the Practice Guidelines for Management of the Difficult Airway by the American Society of
Anesthesiologists (ASA) define the difficult airway as difficult facemask ventilation of
the upper airway, difficult tracheal intubation, or both. preoperative assessment of the
airway avoids that risk; however, current clinical screening tests have low sensitivity
and specificity with limited predictivity.
Ultrasound (US) provides a more precise assessment for tissues like epiglottis, vocal
cords, and ring-shaped membranes; thus, it facilitates a bedside, non-invasive objective
airway assessment. Moreover, ultrasound assessment can plan and guide airway
interventions if needed. The airway in pregnancy goes through changes. a study concluded
that The US airway assessment parameters differ significantly between pregnant and
non-pregnant patients. Previous studies reported that the best predictors of difficult
laryngoscopy and/or difficult intubation were the epiglottis midline-skin distance, hyoid
bone-to-skin distance, thyroid cartilage-to-skin distance, thyrohyoid membrane-to-skin
distance, and vocal cord anterior commissure-skin distance also predicted difficult
airway. In Pregnancy, hyoid bone visibility, and Pre-E/E-VC ratio were independent
predictors of the difficult airway.
Researchers suggested different techniques for airway ultrasound. Some suggested detailed
technique that allows the determination of multiple parameters. Others suggested a more
concise protocol to lessen the time of assessment and to avoid complexity.
This trial assesses the superiority of either 2 views or 5 views ultrasound assessment in
predictivity of difficult airway (difficult ventilation, laryngoscopy, and intubation)
and their comparison to traditional clinical examination by El-Ganzouri index (GREI) (9)
in critically ill obstetric patients with pre-eclampsia.