EFFECTS OF TRACHEAL SUCTIONING ON RESPIRATORY RESISTANCES IN MECHANICALLY VENTILATED PATIENTS

Objective: To evaluate the effects of tracheal suctioning (TS) on resp iratory resistances in sedated critical care patients receiving mechan ical ventilation (MV). Setting: Surgical ICU of Bichat Hospital, Paris . Patients and participants: Thirteen sedated critical care patients r eceiving MV for various conditions. Measurements and results: Airway r esistances (R-1), airway and pulmonary resistances (R-2), and intrinsi c positive end-expiratory pressure (PEEPint) were measured according t o the end-inspiratory and end-expiratory occlusion methods before and after TS. R-1 and R-2 increased by 49.1% and 46.3%, respectively, 0.5 min after TS (p<0.01) but returned to baseline values atl 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 persist ently reduced at 30 min (p<0.01). Nine patients received 500 mu g of i nhaled albuterol before another suctioning procedure. R-1 and R-2 decr eased by 11.5% and 9.9%, respectively, 20 min after inhalation (p<0.05 ), but the R-1 and R-2 initial increase following TS did not differ be tween the true suctioning procedures. Conclusions: TS evokes only a tr ansient bronchoconstrictor response, but thereafter, does not reduce r espiratory resistances below presuctioning values. However, the decrea se of PEEPint following TS suggests an increase of expiratory flow. Ef fective beta(2)-adrenergic receptor blockade fails to suppress the TS- induced bronchoconstrictor response.