Airway obstruction with cricoid pressure

Abstract

SummaryCricoid pressure may cause airway obstruction. We investigated whether this is related to the force applied and to the technique of application. We recorded expired tidal volumes and inflation pressures during ventilation via a facemask and oral airway in 52 female patients who were anaesthetised and about to undergo elective surgery. An inspired tidal volume of 900 ml was delivered using a ventilator. Ventilation was assessed under five different conditions: no cricoid pressure, backwards cricoid pressure applied with a force of 30 N, cricoid pressure applied in an upward and backward direction with a force of 30 N, backwards cricoid pressure with a force of 44 N and through a tracheal tube. An expired tidal volume of < 200 ml was taken to indicate airway obstruction. Airway obstruction did not occur without cricoid pressure, but did occur in one patient (2%) with cricoid pressure at 30 N, in 29 patients (56%) with 30 N applied in an upward and backward direction and in 18 (35%) patients with cricoid pressure at 44 N. Cricoid pressure applied with a force of 44 N can cause airway obstruction but if cricoid pressure is applied with a force of 30 N, airway obstruction occurs less frequently (p ¼ 0.0001) unless the force is applied in an upward and backward direction.

The cricoid cartilage and the esophagus are not aligned in close to half of adult patients

“…Its use has also been associated with serious complications including distorted laryngeal view, increased difficulty with intubation, laryngeal trauma, cricoid fracture, and esophageal rupture. [11][12][13][14][15] To date, there has never been a randomized, controlled study assessing the effectiveness of CP. Schreiner has pointed out the difficulty of conducting such a study given the low event rates for regurgitation and pulmonary aspiration.…”

Clinical Evaluation of the Cricoid Pressure Effect on Bag Mask Ventilation, ProSeal Laryngeal Mask Airway Placement and Ventilation

“…In the event of a 'cannot intubate' scenario, the manual face mask ventilation of the lungs with oxygen with continued CP application is an imperative (13). We found that CP significantly hampered BMV compared to no CP (41.7% vs. 98.3%, respectively).…”

“…Previous studies confirm impairment of ventilation via the classic LMA, when CP was applied prior to device insertion (12,14,15). Application of CP may cause laryngeal obstruction due to cricoid cartilage deformation or tilting resulting in a vocal cord closure (13). Tilting of the cricoid cartilage resulting in airway obstruction is more likely to occur with classic LMA placement, as its tip lies behind the upper part of the cricoid (16).…”

“…Manual CP is more accurately placed on the cricoid cartilage and represents clinical practice. However, a uniform force is not applied in each case (13). The use of CP in RSI/I is an accepted standard of care in non-fasting patients and in those at risk of aspiration.…”

Cricoid pressure with the Truview Evo2TM laryngoscope improves the glottic view

“…There is also conflicting evidence regarding the effect of cricoid pressure (CP) on the laryngoscopic view with the conventional Macintosh laryngoscope. [6][7][8][9][10] The Truview Evo2 TM blade (Truphatek Holdings Ltd, Netanya, Israel) enables an indirect view of the vocal cords and may improve glottic visualization compared with the conventional Macintosh laryngoscope. 11,12 The Truview Evo2 blade, based on a combination of an optical system with a steel blade, provides a 42°angled view (refracted) through a 15-mm eyepiece.…”