Measurement of tracheal wall pressure: a comparison of three different in vitro techniques

Abstract

SummaryWe compared three different tracheal wall pressure measuring techniques in vitro. Using a highvolume, low-pressure, cuffed tracheal tube with an internal diameter of 7.5 mm and a model trachea, the pressure difference technique, the wall pressure membrane technique and the microchip sensor probe technique with and without lubrication were studied. Wall pressures were measured after sequential injections of 0.5 ml of air into the cuff at cuff pressures ranging from 0 to 50 mmHg. The coefficient of variance was largest for the microchip sensor probe technique with lubrication (29%) and without lubrication (214%), and was lower for the wall pressure membrane technique (22%) and the pressure difference technique (19%). The wall pressure membrane and pressure difference techniques provided comparable results. The microchip sensor probe technique considerably underestimated wall pressure. These findings have an impact on the interpretation of published data on tracheal or pharyngeal wall pressure using the microchip sensor probe technique.

Directly measured mucosal pressures produced by the i‐gelTM and laryngeal mask airway SupremeTM in paralysed anaesthetised patients

“…Mucosal pressures were measured directly using four 1.2‐mm diameter strain gauge silicone microchip sensors (Codman ® MicroSensor TM ; Johnson and Johnson Medical Ltd, Raynham, MA, USA) attached to the external surface of the devices with clear adhesive dressing 0.45 μm thick (Tegaderm TM , 3M, Ont., Canada), as previously described [5–7]. The sensors were fully covered with lubricant jelly and applied to mucosal areas corresponding to the following locations: (A) anterior base of cuff to base of tongue; (B) posterior tube todistal oropharynx; (C) posterior tip of cuff to hypopharynx; and (D) anterior middle part of cuff side to pyriform fossa (Fig.…”

“…The sensing elements of sensors were orientated towards the mucosal surfaces. The position and orientation of all the sensors were checked in vitro before and after use in each patient [5–7].…”

In‐vitro analysis of a novel ‘add‐on’ silicone cuff to improve sealing properties of tracheal tubes

“…We applied methods previously validated by Horisberger et al. . Briefly, an intracranial pressure sensor probe (Codman, Raynham, MA, USA) was placed over the internal surface of our tracheal model to assess cuff pressure transmitted against the tracheal wall.…”

“…Each test was repeated three times and a new cuff was used for each test. We applied the aforementioned methods to measure transmitted tracheal pressures . The intracranial pressure sensor probe and pressure transducer were able to monitor and record transmitted tracheal pressures within a range of 0 and 72 cmH 2 O.…”

Association of Oversized Tracheal Tubes and Cuff Overinsufflation With Postintubation Tracheal Ruptures

“…In vivo animal studies have shown microscopic alterations of the tracheal wall depending on the cuff shape [ 18 ]. In vitro studies used a tracheal cadaver [ 19 ] or model trachea [ 20 ] to determine mucosal pressures. These studies used the recommended volume or pressure according to the manufacturers' instructions.…”