A Randomised Controlled Trial of Minimal Occlusive Volume (MOV) technique compared to Cuff Pressure Monitoring (CPM) in Endotracheal and Tracheal Cuff Management

Mechanical ventilation is a life saving treatment that is used every day in Intensive Care for people with serious breathing difficulties. In order to provide mechanical ventilation, it is necessary to insert a tube into the trachea (windpipe). This tube has a balloon around its tip that must be inflated to enable the provision of mechanical ventilation, and prevents oral secretions entering the lower airways, which potentially may cause ventilator-associated pneumonia. The level of inflation of this cuff needs ongoing monitoring (performed 8 hourly) to prevent both secretion aspiration (entry of fluid into the lungs) due to under-inflation, and damage to the tracheal lining due to excessive pressure from over-inflation. Currently, there are two primary methods in use to monitor over and under inflation within Australasia. The minimal occlusive volume technique (MOV) involves addition or removal of sufficient air in the cuff to abolish an air leak. This technique requires deflation of the cuff in order to assess the appropriateness of the cuff inflation volume which may increase the risk of saliva and other secretions entering the lungs. Cuff pressure monitoring measures the pressure within the cuff via a cuff manometer. Titration of the cuff pressure may be performed by addition or withdrawal of small increments of air with a syringe. Full deflation of the cuff is not required. However, the appropriateness of cuff pressure monitoring has been questioned as pressures are influenced by changes in patients’ position and condition. Therefore there is the risk that the cuff may be under inflated for periods of time. The proposed study aims to determine whether there is a detectable difference in the aspiration of blue dye stained secretions when comparing the two techniques; MOV and cuff pressure monitoring. Testing of aspiration of secretions using blue dye is routinely performed in testing for aspiration in patients with swallowing difficulties. Patients will be randomised to have their routine cuff management check performed by either the MOV technique or cuff pressure monitoring. Prior to the procedure, blue dye will be placed on the tongue, routine suctioning will then identify the presence of dye within the patient’s tracheal secretions. There will be minimal risk to patients because both cuff management techniques and the use of blue dye to assess aspiration conform with current international clinical practice guidelines based on sound scientific principles. The potential benefit of the study is to identify the level of aspiration associated with either technique in order to inform current practice guidelines that may assist in the prevention of ventilator associated pneumonia.