TRacheal Cuff PRessure Evaluation Study

Overview

Randomized clinical trial in mechanically ventilate critically ill patients. The study will evaluated the efficacy of a continous endotracheal tube (ETT) cuff pressure controller (TRACH FLUSH group) compared to manual monitoring and inflation (STANDARD group). Patients intubated, from at least 24 hours and with a predicted duration of invasive mechanical ventilation longer than 72 hours, will be randomized to the use of TRACH FLUSH versus nurse operated analogic cuff pressure controller q8. Hypotesis of the study is the superiority of the continuous cuff pressure controller in maintaining cuff pressure within the target value, thus decreasing the incidence of microaspiration events. Aim of the study are 1) to compare the incidence of cuff pressure value detection outside the target range between the TRACH FLUSH and the STANDARD group, and 2) to compare the incidence of sputum samples positive for (amylase and/or pepsin), a surrogate for tracheal micro-aspiration event.

Endotracheal intubation is an effective method of providing rapid and safe airway patency and respiratory support in the intensive care unit (ICU). Endotracheal intubation effectively isolates the trachea by inflating the endotracheal tube (ETT) cuff just below the vocal cords: this ensures airway patency and positive pressure ventilation. The pressure of the endotracheal tube cuff (Pcuff) should be between 20-30 cmH2O to ensure airway isolation. The literature reports that overinflation of the endotracheal cuff (\>30 cmH2O) causes hoarseness, sore throat, inadequate swallowing of secretions, tracheal stenosis, tracheal wall damage, and ischemia due to decreased mucosal capillary blood flow: these changes can occur even if a high Pcuff is maintained for a short period of time. In contrast, inadequate inflation (less than 20 cmH2O) results in ventilation-associated pneumonia (VAP) due to ineffective ventilation and microaspiration of gastric and/or oropharyngeal secretions into the lungs. Risk factors for microaspiration include patient-related factors, factors related to endotracheal tube type, performance of invasive procedures such as enteral nutrition through a nasogastric or orogastric tube, and mechanical ventilation. Patient-related factors include supine position, sedation, coma, tracheal diameter, and viscosity of secretions, while among those related to tube type we find impossible vocal cord closure, longitudinal folds of low-pressure and high-volume polyvinyl chloride (PVC) tracheal tubes. The American Association of Critical-Care Nurses (AACN) states that in order to achieve adequate pressure and prevent mucosal damage, the amount of pressure and volume of air needed, the size, shape of the tube, mode of mechanical ventilation, and the patient's blood pressure must be taken into account. The methods found in ICUs to control Pcuff and keep it within safe ranges are about a dozen and range from manual external palpation of the inflation balloon, to assessment of inspiratory/expiratory volume loss to continuous monitoring with appropriate instrumentation. Despite the known Pcuff-related complications of ETT, there is a paucity of national or international guidelines on the optimal pressure value, frequency of pressure measurement, and measurement methods: however, some studies performed show that the use of an automated device that continuously monitors Pcuff significantly decreases gastric microaspirations.