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Performance of automated air tonometry under hypothermia
Author(s) -
Weiss M.,
Dullenkopf A.,
Hasenclever P.
Publication year - 2005
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.2005.04216.x
Subject(s) - medicine , hypothermia , anesthesia , perfusion , splanchnic , balloon catheter , catheter , surgery , hemodynamics
Summary Intestinal tonometry is used during hypothermic cardio‐pulmonary bypass surgery to assess splanchnic perfusion. In an in vitro set‐up the performance of automated air tonometry (TONOCAP ® ) was tested for normo‐ and hypothermia. A 14‐FG tonometry catheter was built into a testing chamber (100 cm 3 ) perfused with blood from a cardio‐pulmonary bypass circuit with P a co 2 held at 5.6–5.8 kPa (alpha‐stat). P r co 2 from the balloon of the tonometry catheter was measured at intervals of 10 min at 37 °C and at 25 °C by the TONOCAP ® . Bias (precision) of P r co 2 – P a co 2 alpha‐stat and P r co 2 − P a co 2 pH‐stat at 37 °C blood temperature were low at 0.23 kPa (0.21) each. Tonometrically measured P r co 2 at 25 °C significantly differed from P a co 2 alpha‐stat bias (precision) of 2.00 kPa (0.11) but was similar to P a co 2 pH‐stat (0.30 kPa (0.11)). P r co 2 values as measured by the TONOCAP ® represent pH‐stat approach. Identical blood gas management (pH‐ or alpha‐stat) should be used for calculation of mucosal – arterial CO 2 difference (P r–a co 2 gap) or calculation of intramucosal pH.