Ventilator Associated Complications in Neonate and Small Infant Undergoing Cardiac Surgery Using Cuffed and Uncuffed Tracheal Tubes. The PICU-BG-TT Study

Ventilator associated pneumoniae (VAP) occurs in 9-27% of all intubated patients and is associated to an important morbidity and mortality. It is a serious complication among neonates and pediatric patients after cardiac surgery accounting for 6.8-32.2% of health-care associated infections. Ventilator associated tracheobronchitis (VAT) is common in adults and it has been described as a risk factor for the development of VAP. Studies have shown that treatment of VAT is associated with a lower rate of VAP and a lower mortality in adult patients. VAT has also been described in premature infants and children but it has been less studied than in adults.Recently, the Centers for Disease Control and Prevention (CDC) rolled out new surveillance definitions for patients receiving mechanical ventilation to be more objective and to render the data easier to collect and verify. The terms include ventilator-associated condition (VAC) and infection-related, ventilator-associated complication (IVAC). Studies in adults demonstrated that the VAC assessment was faster, more objective, and a superior predictor of outcomes. However, this approach has not yet been applied systematically to infants and children.For more than 50 years, uncuffed tracheal tubes have been commonly used for intubation in children under 8 years of age because of the anatomy of the pediatric larynx and the fear that the cuff will cause airway mucosal injury, leading to subglottic stenosis. However, since 2009, it is registered and available a new cuffed tracheal tube (TT) with an anatomically designed high volume-low pressure tube cuff, with a recommendation chart for tube size selection has recently become available for pediatric anesthesia.Weiss and colleagues enrolled 2246 patients in a randomized multi-centre trial and reported no increase of risk for post-extubation stridor with the use of the new microcuffed.Considering that microaspiration of contaminated oral secretions is one of the mechanisms leading to VAP and VAT, the use of cuffed TTs may be beneficial in VAP prevention as the superior tracheal seal may decrease the incidence of micro-aspiration. However, no study evaluated the incidence of VAP with the use of cuffed tracheal tubes is published since now.Despite of these new evidence, the use of uncuffed tube in neonatal and pediatric critical care still remain very common to minimize minor complications (i.e. mucosal damage due to the cuff), and consequently the use of cuffed or uncuffed tubes is equally recommended.The management of anesthesia according to standards procedures of the Bergamo anesthesia department is shifting from the uncuffed tubes only to microcuffed tubes, and it is aim of the present study to monitor this transition measuring the performance of the two TTs in terms of incidence of VAP and VAT (according to the CDC old definition) and in term of incidence of VAC and IVAC (according to CDC new definition).The CDC definition was used to identify patients with VAP and VAT. The CDC definition of VAP for infants < 1 y.o. and children > 1 or < 12 y.o. are based on clinical and X-ray criteria. The CDC definition of Tracheitis are based on absence of clinical and radiographic evidence of pneumonia and the following criteria: positive culture obtained by deep tracheal aspirate and 2 signs of symptoms with no recognizable cause [such as fever (>38.5°C), cough, new or increased sputum production, rhonchi, or wheezing].

The new CDC definition is used to identify patients with VAC and IVAC. The new definitions includes all associated complications (infection included) related to mechanical ventilation and exclude X-ray criteria.

VAP, VAT, VAC, IVAC rate, expressed as the number of VAP/VAT/VAC/IVAC episodes per 1000 mechanical ventilator days (VAP/1000 MV days), were calculated for phase 1 and phase 2.