Safe and effective pressure of endotracheal tube suctioning based on sputum viscosity grades during artificial airway open suctioning procedures: A double-blind randomized controlled trial

Background: Endotracheal tube suctioning is an effective measure to ensure airway patency during mechanical ventilation; however, inappropriate suction pressure often leads to many adverse effects.

Aims: This study aimed to investigate safe and effective suction pressures and intracatheter pressure ranges during artificial airway open suctioning procedures.

Study design: In this double-blind randomized controlled trial, 438 patients receiving mechanical ventilation in China were divided into nine groups according to their sputum viscosity grades and suction pressure. A random sampling method was used to select one of the three pressure groups (low-, medium- and high-pressure groups). Registered intensive care unit (ICU) nurses performed open suction manoeuvres of the artificial airway based on the pressures set by the researchers. Two teaching supervisors observed and recorded the sputum viscosity, suction pressure, minimum intracatheter pressure, maximum intracatheter pressure, heart rate, mean arterial pressure, pulse oxygen saturation, airway mucosal bleeding and sputum sound improvement score.

Results: This study finally included 438 patients. The results showed that the safe and effective suction pressures were 80-120 mmHg for grade I sputum viscosity, 150 mmHg for grade II sputum viscosity and 200 mmHg for grade III sputum viscosity in open suction procedures for ICU patients. These pressure values were associated with the lowest changes in heart rate, mean arterial pressure and pulse oxygen saturation; the lowest incidence of airway mucosal bleeding; and the highest sputum sound improvement score.

Conclusions: In an open suction procedure, accurate setting of safe and effective suction pressure for sputum of different viscosity grades can not only achieve the suction effect but also have minimal impact on the vital signs and airway mucosal bleeding of patients.

Relevance to clinical practice: The findings can guide critical care nurses to accurately select safe and effective initial suction pressure values rather than use general ranges when performing artificial airway open suctioning procedures.