Apparatus for respiratory therapy, which is particularly useful in a neonatal context, and related methods, the apparatus comprising an adaptor for connection to the exposed fitting of an indwelling endotracheal tube of any one of several types to an aspirating apparatus which may include ventilating capacity. The adaptor includes an appendage by which a lavage solution can be selectively introduced into the lungs of a patient through the indwelling endotracheal tube to loosen secretions without necessarily interrupting the ventilation cycle or requiring that the ventilating circuit be broken. The apparatus also comprises a fitting at one end of an aspirating/ventilating apparatus which has low dead space, alleviating the incidence of inadvertent disconnection and trauma induced by unintended displacement of the end fitting and accommodating not only aspiration and ventilation but also monitoring of certain vital indicators to allow prompt medical response to contraindications. The apparatus further comprises a manual stationary insertion guide for introduction of the suction catheter tube into the respiratory system of the patient and control stop structure which accommodates insertion into the respiratory system of the patient of only a predetermined length of the suction catheter tube. The apparatus also comprises structure by which the flow of secretions through the suction catheter tube can be visually monitored.