Suction forces generated by passive bile bag drainage on a model of post-subdural hematoma evacuation

Steven O. Tenny, William E. Thorell

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Background Passive drainage systems are commonly used after subdural hematoma evacuation but there is a dearth of published data regarding the suction forces created. We set out to quantify the suction forces generated by a passive drainage system. Method We created a model of passive drainage after subdural hematoma evacuation. We measured the maximum suction force generated with a bile bag drain for both empty drain tubing and fluid-filled drain tube causing a siphoning effect. We took measurements at varying heights of the bile bag to analyze if bile bag height changed suction forces generated. Results An empty bile bag with no fluid in the drainage tube connected to a rigid, fluid-filled model creates minimal suction force of 0.9 mmHg (95% CI 0.64–1.16 mmHg). When fluid fills the drain tubing, a siphoning effect is created and can generate suction forces ranging from 18.7 to 30.6 mmHg depending on the relative position of the bile bag and filled amount of the bile bag. The suction forces generated are statistically different if the bile bag is 50 cm below, level with or 50 cm above the experimental model. Conclusion Passive bile bag drainage does not generate significant suction on a fluid-filled rigid model if the drain tubing is empty. If fluid fills the drain tubing then siphoning occurs and can increase the suction force of a passive bile bag drainage system to levels comparable to partially filled Jackson-Pratt bulb drainage.

Original languageEnglish (US)
Pages (from-to)1305-1309
Number of pages5
JournalActa Neurochirurgica
Issue number12
StatePublished - Dec 2018


  • Bile bag
  • Drain
  • Subdural hematoma
  • Suction force

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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