Setting safe and effective suction pressure: the effect of using a manometer in the suction circuit

Objectives: To establish the levels of pressure used to perform tracheal su ction (TS) and if they are affected by having a manometer visible in the su ction circuit. Design: A bench test evaluation of simulated tracheal suction. Setting: Physiotherapy department of a major teaching hospital in Melbourne , Australia. Participants: Sixty-four nurses and physiotherapists who regularly apply TS to patients in the intensive care units of this hospital. Interventions: All subjects used both circuit A (without a visible manomete r) and B (with a visible manometer) in a predetermined random order. For bo th, subjects adjusted the suction control tap to where they said a safe and effective pressure (set pressure) was delivered:and then occluded the suct ion catheter as though suctioning (applied pressure). Subjects then complet ed a questionnaire on their current TS practise. Measurements and results: All set pressures (mean = 228.57 mmHg) and all ap plied pressures (mean = 359.52 mmHg) were significantly higher (P < .001) w hen compared to the expected pressures (mean = 135 mmHg). Pressures set wit hout a visible manometer (circuit A) were significantly higher (P < .05) th an those using a visible manometer (circuit B) but the applied pressures we re not significantly different (P = .166). Neither the investigator (P = .6 18) or the test order (P = .167) had a significant effect on the outcome. Q uestionnaire results showed 31% of subjects considered 100-170 mmHg a safe and effective suction pressure whilst none reported using an objective mean s of measuring pressure. Conclusion: All pressures in both circuits were significantly higher than t hose recommended as safe in the literature. In addition, pressures were una ffected by the inclusion of a visible manometer in the suction circuit.