The purpose of this study is to evaluate the efficacy of tracheal suctioning associate with expiratory pause maneuver in children on invasive mechanical ventilation.

After being informed about the study and potential risks, all parents or guardians giving written informed consent will be evaluate for study entry. Children in invasive mechanical ventilation who meet eligibility criteria will be submitted of two techniques of tracheal suctioning (with and without expiratory pause maneuver), randomized in a crossover trial in a 1:1 ratio, for determine the first technique to be applied.

Clinical data will be collected (sex, age, presence of previous disease, diagnosis of hospitalization), as well as the ventilatory parameters (ventilation mode, peak inspiratory pressure, positive end-expiratory pressure, tidal volume, respiratory frequency, fraction of inspired oxygen).

The protocol consists of an initial conventional tracheal suctioning with a negative pressure of 40mmHg for all the participants. After two (2) hours the first technique will be applied and an interval of another two hours for the application of the second technique. Respiratory mechanics and hemodynamic parameters will be evaluate before and after 30 minutes of each tracheal suctioning techniques.

In case of clinical alterations that may aggravate the patients condition during the protocol (oxygen saturation < 85%, heart rate > 190bpm and/or decrease 20% of mean arterial blood pressure), the technique will be interrupted immediately and the patient will be evaluated.

Inclusion Criteria:

• Children at invasive mechanical ventilation for more than 24 hours;
• Under the effect of neuromuscular blocker (level of sedation assessed using the Comfort B Scale with a score <10 and without a cough reflex);
• Endotracheal suctioning in a period > 2h before the application of the technique.

Exclusion Criteria:

• Patients with undrained pneumothorax or hemothorax, or presence of subcutaneous emphysema;
• Hemodynamic instability (hypotension refractory to treatment)
• Need of frequent endotracheal suctioning