Nasogastric tube "suction-buster holes" release mucosal occlusion despite high suction.
Aspiration devices can persistently malfunction if moderate (not just high) suction causes mucosal occlusion of every opening. The standard pattern of uniformly large orifices was modified by supplementing half the nasal tubes with smaller (one tenth of the area) openings. Ten pairs of postoperative patients sipped water while suction applied to their nasal tubes varied from 40 to 300 mm Hg. Unmodified tubes consistently functioned only when applied vacuum was below 60 mm Hg. At 60 mm Hg, 20% (2/10) of tubes malfunctioned, with swallows failing to return on three consecutive attempts even at this gentle level. The failure rate rose with increasing applied suction. All 10 devices evidenced persistent occlusion when the vacuum exceeded 90 mm Hg. Each adverse result was confirmed by continued malfunction when suction was increased by another 10 mm Hg. The brisk flow through large esophageal openings dramatically differs from restricted inflow. Supplementing the standard set of uniform, large-bore aspiration orifices with additional small openings results in unimpeded function over the full range of available hospital vacuum. The additional small openings permitted the turbulent evacuation characteristic of large-bore patency. No device with accessory "suction-buster" orifices malfunctioned at even the highest available suction (300 mm Hg).
Moss
G
G
Department of Biomedical Engineering, School of Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590.
D002763:Cholecystectomy; D004326:Drinking; D004868:Equipment Failure; D004947:Esophagus / Q000473:pathology*; D006801:Humans; D007441:Intubation, Gastrointestinal / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D009092:Mucous Membrane / Q000473:pathology; D011182:Postoperative Care; D013396:Suction