Patient-triggered ventilation using cutaneous sensors

Abstract

Patient-triggered ventilation (PTV) prevents asynchrony between spontaneous and ventilator breaths which can be problematic on conventional intermittent mandatory ventilation (IMV). Cutaneous sensors sensitively detect spontaneous breathing in very low birthweight infants despite very small spontaneous airway flow or pressure changes, and lack interference due to air leaks, secretions or surfactant in the airway. The Star Sync module and the Graseby capsule taped to the abdomen enable the InfantStar ventilator to provide the synchronized intermittent mandatory ventilation (SIMV) and assist-control (A/C) modes of PTV. Short-term studies in very low birthweight infants have shown better oxygenation, increased and more consistent tidal volumes and reduced cerebral blood flow velocity variability on SIMV than on IMV. A large, multicentre randomized trial showed an overall reduction in mean airway pressure, and in specific birthweight groups there was improved oxygenation, decreased need for sedation, shorter duration of ventilation, less need for long-term supplemental oxygen and earlier weight gain on SIMV than on IMV. The Sechrist IV-200 synchronized assisted ventilation of infants (SAVI) system uses modified transthoracic impedance to produce PTV and it decreased the duration of ventilation in very low birthweight infants in one study. Appropriate cutaneous placement of the sensors of both of these systems is necessary in order to optimize the clinical response time and reliability of PTV. Since their cutaneous sensors are not affected by airway leak, both systems may be used to reliably provide PTV via nasal prongs.