Response to: Biphasic cuirass model

Abstract

We would like to bring your attention to another mode of ventilation-the Biphasic Cuirass Ventilation (BCV) model which has many advantages in the pediatric population. BCV relies on a plastic cuirass shell (available in sizes from neonates to adult) connected to a ventilator which produces negative pressure on the thorax allowing air to rush in through the nose and mouth and into the lungs-release of the negative pressure allows passive exhalation (positive pressure can also be utilized to gently "push" the tidal volume out of the lungs). As long as airway patency is maintained, a patient can be efficiently ventilated and oxygenated, even during muscle relaxation with paralytics. Neuromuscular blockade would eliminate the possibility of laryngospasm and potentially create safer operating conditions for both the patient and the surgeon. 2 Biphasic Cuirass Ventilation has successfully been used during airway and tracheal procedures. 3 Its advantages over positive pressure ventilation include the decreased risk of barotrauma (especially a danger with jet ventilation), better clearance of secretions, and possibly improved CO2 removal from the body. 2Additionally, as mentioned in your article, subglottic stenosis is more commonly acquired by post-intubation laryngeal injury but this can be avoided by using BCV as an alternative to more invasive methods. It has also been effective in the management of a patient with severe tracheal stenosis 4 so even "compromised" airways may benefit from its utilization.

Letter to the Editor: Biphasic Cuirass Model

“…We read with great interest the paper "Accuracy of dynamic preload variables for predicting fluid responsiveness in patients with pediatric liver cirrhosis: A prospective study" by Chen et al 1 In our opinion, there is another reason for the low prognostic value of dynamic parameters to predict fluid responsiveness (FR) in their study. The children were mechanically ventilated with tidal volume of 8 mL/kg, lower than the 10 mL/kg protocols used in earlier comparable studies, [2][3][4] and currently a lung protective strategy with smaller tidal volume is preferred by some or most anesthesiologists in clinical practice. Furthermore, they used positive end expiratory pressures (PEEP) of 5 cm H 2 O.…”

“…Previous study demonstrated that diagnostic accuracy to predict FR decreases with the use of PEEP and smaller tidal volume. 4,5 The hypothesis that the accuracy of dynamic preload variables to predict FR is reduced in children with liver cirrhosis because they may have lower systemic vascular resistance and higher vascular compliance is reasonable, though their data demonstrated cardiac index and systemic vascular resistance were "comparable to the normal ranges in children without cirrhosis." So the accuracy of dynamic parameters to predict FR in children with typical hyperdynamic circulation remains unclear.…”