Analysis of an Anesthesia and Intensive Care Ventilators during Suctioning through a Fiber-optic Bronchoscope

Abstract

Background: The aim of this bench test was to compare the performance of an anesthesia and an intensive care ventilator during Fiber-optic Bronchoscopy (FOB) suctioning. Methods: In a lung model, a 5.9 mm OD FOB was inserted into an endotracheal tube through a tight-fitting connector. Pressure and flow sensors were placed at the airways opening (Pao) and distal to the bronchoscope at the trachea (Ptr). This model was tested under pressure and volume controlled mandatory ventilation and during Continuous Positive Airway Pressure (CPAP) delivered by both, anesthesia and intensive care ventilators. End-expiratory pressure was set at 10 cm H2O. Measurements were performed during suctioning with a mean negative flow of -12 ± 0.2 L/min at the tip of the FOB. Results: The anesthesia ventilator failed to keep end-expiratory pressure above zero at the trachea during FOB suctioning using both, continuous mandatory ventilation and CPAP. When using an intensive care ventilator, Ptr decreased below zero during FOB suctioning during volume controlled ventilation but remained slightly above zero under pressure controlled ventilation. When this ventilator delivered 10 cm H2O of CPAP, Pao remained constant while Ptr decreased by 2.5 cm H2O during suctioning. Conclusion: During FOB suctioning, targeted Ptr could neither be maintained anesthesia nor intensive care ventilators used in mandatory modes of ventilation. Only CPAP administered by the intensive care ventilator kept Ptr reasonably stable during suctioning.