Effects of tracheal suctioning on respiratory resistances in mechanically ventilated patients

Abstract

Objective: To evaluate the effects of tracheal suctioning (TS) on respiratory resistances in sedated critical care patients receiving mechanical ventilation (MV).

Setting: Surgical ICU of Bichat Hospital, Paris.

Patients and participants: Thirteen sedated critical care patients receiving MV for various conditions.

Measurements and results: Airway resistances (R1), airway and pulmonary resistances (R2), and intrinsic positive end-expiratory pressure (PEEPint) were measured according to the end-inspiratory and end-expiratory occlusion methods before and after TS. R1 and R2 increased by 49.1% and 46.3%, respectively, 0.5 min after TS (p<0.01) but returned to baseline values at 1 min without any change thereafter. PEEPint decreased progressively following TS to reach a significant level (-13.3%) at 10 min (p<0.05) and was persistently reduced at 30 min (p<0.01). Nine patients received 500 microg of inhaled albuterol before another suctioning procedure. R1 and R2 decreased by 11.5% and 9.9%, respectively, 20 min after inhalation (p<0.05), but the R1 and R2 initial increase following TS did not differ between the two suctioning procedures.

Conclusions: TS evokes only a transient bronchoconstrictor response, but thereafter, does not reduce respiratory resistances below presuctioning values. However, the decrease of PEEPint following TS suggests an increase of expiratory flow. Effective beta2-adrenergic receptor blockade fails to suppress the TS-induced bronchoconstrictor response.