Oxygen Supplementation and Ventilator Hyperinflation in the Endotracheal Suction (OSVHES) (OSVHES)

Effects of Low Oxygen Supplementation and Ventilator Hyperinflation in the Endotracheal Suction of Mechanically Ventilated Patients

This is a double crossover study where all patients are randomly allocated to one of two treatment sequences associated with endotracheal aspiration.The first treatment (A) uses two suctioning methods for each patient: one involving hyperoxygenation with administration of 100% oxygen 1 minute before and after suction (intervention I), and the other hyperoxygenation with oxygen supply to 20% above basal offer (Intervention II) in the same way.The second treatment (B) uses a technique of hyperinflation with the mechanical ventilator (PEEP-ZEEP) associated with hyperoxygenation. The intervention I, uses PEEP-ZEEP offering 20% above basal oxygenation and intervention II uses the PEEP-ZEEP with basal oxygen supply in the same way. All subjects were randomly allocated using sealed envelopes to a treatment sequence A or B on Day 1. Patients received two treatments, at least four hours apart. The first treatment is in the morning and the alternate treatment is performed in the afternoon. On Day 2 the order of the treatments was reversed using the same patient position sequence.The interventions I and II are performed at least 4 hours apart to minimize any carryover effect.

Endotracheal suction must be carried out only through precise indication, because it is associated with undesirable effects on the hemodynamic parameters, ventilation, oxygenation and respiratory mechanics. The hyperoxygenation is one of the methods of prevention of hypoxemia induced by tracheal suction procedure and have been proposed for its efficiency. Another method is the hyperinflation with the mechanical ventilator. Ventilator hyperinflation improves oxygenation, mobilizes the bronchial secretion excess and re-expand the lung collapsed areas. The PEEP-ZEEP is a ventilator hyperinflation technique, described as a lung inflation through a positive pressure enhancement at the end of expiration (PEEP), followed by rapid lung deflation with an abrupt reduction in the PEEP to ZEEP (0 centimeters of water (cmH2O)).

Respiratory mechanics, Oxygenation, Suction, Mechanical ventilation, Respiratory therapy, Capnography, Pulmonary Ventilation

Endotracheal suction associated with Hyperoxygenation involved supplying 20% oxygen above FiO2 basal.

Endotracheal suction associated ventilator hyperinflation (PEEP-ZEEP maneuver) and involved no hyperoxygenation, keeping the oxygen already offered to the patient.

Endotracheal suction associated ventilator hyperinflation (PEEP-ZEEP maneuver) and hyperoxygenation involved supplying 20% oxygen.

Oxygenation is evaluated by peripheral oxygen saturation (SpO2), measured by a respiratory monitor (DX-2021™ or DX-2023™- Dixtal™. The Impact on oxygenation was detecting hypoxemia with SpO2 values below 90%. Ventilation is evaluated by end-tidal carbon dioxide measured by carbon dioxide sensor (CAPNOSTAT CO2 Sensor, Novametrix Medical Systems Inc.) inserted into the mechanical ventilator circuit Dixtal 3012™ - Dixtal™. The impact on ventilation was detecting hypoventilation with values exceeding 50 mmHg.

Endotracheal suctioning is carried out according each protocol. Oxygen (SpO2) and ventilation (ETCO2) measures are performed before and after supply oxygen given for 1 minute, 60 seconds after each suctioning, immediately after and 30 minutes the end.

Respiratory mechanics was measured by mechanical ventilator Dixtal 3012™- Dixtal™. Its impact will be evaluated by the changes of parameters of normality of variables: auto-PEEP, dynamics compliance (Cd), static compliance (Cst), airway resistance (rva), Airway occlusion pressure (P0.1), slow vital capacity (SVC) and maximal inspiratory pressure (MIP).

Endotracheal suctioning is carried out according each protocol. Baseline Respiratory mechanic measures are performed before suctioning, immediately after and 30 minutes the end.

Volumetric capnography was evaluated by carbon dioxide sensor (CAPNOSTAT CO2™ Sensor, Novametrix Medical Systems Inc.) measured by mechanical ventilator Dixtal 3012™- Dixtal™. Its impact will be evaluated by the changes of parameters of normality of variables: ETCO2, anatomical dead space/tidal volume ratio (Vd/VT), alveolar dead space (Vd), alveolar ventilation (Va), maximal tidal elimination of carbon dioxide (VtCO2), carbon dioxide production (VCO2) and partial pressure of expired (PeCO2).

Endotracheal suctioning is carried out according each protocol. Baseline Volumetric capnography measures are performed before suctioning, immediately after and 30 minutes the end.

Inclusion Criteria: Mechanical ventilation for more than 12h Hemodynamic stability Presence of indication criteria of endotracheal aspiration procedure Exclusion Criteria: High doses of vasopressor amines amines and/or severe arrhythmias Hemoglobin < 7 g/dL FiO2 ≥ 0.6 PEEP ≥ 10 cmH2O Conditions: rib fractures, chest drain, severe bronchospasm, pneumothorax not drained and tracheostomy Contraindications of ventilator hyperinflation(PEEP-ZEEP): intracranial pressure > 10 mmHg, bleeding disorders, accented degrees of gastroesophageal reflux and bullous lung disease.

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