Does cooling Sengstaken-Blakemore tubes aid insertion? An evidence based approach.

OBJECTIVE: To survey current clinical practice concerning the use of Sengstaken-Blakemore (SB) tubes and to determine whether cooling the tubes alters their stiffness.

METHODS: A telephone questionnaire was conducted of gastroenterology registrars and ITU departments in the North Thames region. The current clinical practice for insertion of SB tubes and the basis for this practice were determined in each case. The stiffness of the tubes was measured at -10 degrees C and 20 degrees C by measuring the extension (in mm) resulting from an applied load (in newtons). The time for tube warming from -30 degrees C when in stationary air and when in contact with skin was also recorded.

RESULTS: Fifty registrars were contacted and 20 ITU departments were surveyed. All ITU departments involved the gastroenterologists in the management of acute variceal bleeds. Eight registrars had never placed an SB tube. The majority of the remainder (95%) used a cooled SB tube. All of the registrars based this practice upon their clinical teaching, and 75% of these registrars thought cooling aided the insertion of the tube. There was no significant difference in the stiffness of the tubes at -10 degrees C and 20 degrees C. Upon warming, an SB tube took 30 s to rise from 0 degrees C to room temperature (20 degrees C) when in skin contact and 120 s when placed in stationary air.

CONCLUSION: The current clinical practice of trainees for the insertion of SB tubes is to cool the tubes in the belief that this 'standard' practice aids tube insertion. We found no significant change in SB tube stiffness even after cooling to temperatures that would not be achieved during routine insertion. Furthermore, the rapid rise in tube temperature means that tubes approach room temperature by the time they reach the bedside. In the present era of evidence based medicine the current dogma that SB tubes should be cooled prior to insertion must be discarded.