Volume Support Ventilation in Infants and Children: Analysis of a Case Series

Abstract

BACKGROUND: Volume support ventilation (VSV) augments a patient's spontaneous respiratory efforts by delivering a patient-triggered, pressure-limited, flow-cycled breath, monitors breath-to-breath changes in the pressure-volume relationship of the respiratory system during spontaneous ven-tilation, and regulates airway pressure to maintain a predetermined minute ventilation. Use of VSV has not been previously reported; consequently, we report our experience with VSV in infants, children, and adolescents. PATIENTS & METHODS: All patients requiring mechanical ventilation in the Pediatric and Infant Intensive Care Units from 12/94 through 12/95 were retrospectively reviewed, and those receiving VSV identified. Demographic data and ventilatory parameters were obtained from the medical record imme-diately before starting, upon initiation of, and at the conclusion of VSV. RESULTS: Twenty children were mechanically ventilated with VSV for part or all of their ICU course. Peak inspiratory pressure (PIP) and set tidal volume (V_T) decreased with the change to VSV [mean (SD): PIP 28.5 (6.3) vs 22.9 (7.3) cm H₂O, p < 0.05; V_T 9.6 (2.7) vs 7.8 (1.9) mL/kg, p < 0.05]. PIP, mean airway pressure (P̅_aw), and V_T decreased between initial and final VSV settings [PIP 22.9 (7.3) vs 18.1 (7.1) cm H₂O, p < 0.05; P̅_aw 9.2 (6.3) vs 7.9 (3.0) cm H₂O, p < 0.05; V_T 7.8 (1.9) vs 6.0 (2.1) mL/kg, p < 0.05]. Eighteen patients (90%) were successfully weaned to extubation. Only 12 of 20 patients (60%) were successfully extubated from VSV. Reasons for failure to wean or extu-bate from VSV included clinician unfamiliarity (5 patients), paralyzed hemidi-aphragm, airway obstruction/tracheal stenosis, and altered respiratory drive (1 each). Four of 5 patients (80%) not extubated from VSV due to clinician unfamiliarity were successfully extubated within a few hours of changing to a different mode of ventilation. CONCLUSION: Although experience with VSV is limited and nuances must be mastered, theoretic advantages (lower airway pressures, enhanced patient comfort, appropriate respiratory mus-cle use, and ease of clinical assessment) may make it useful in selected patients. Further study appears warranted.