Background: Data on tissue oxygen partial pressure (PtO2) and carbon dioxide partial pressure (PtCO2) in human liver tissue are limited. We set out to measure changes in liver PtO2 and PtCO2 during changes in ventilation and a 10 min period of ischaemia in patients undergoing liver resection using a multiple sensor (Paratrend Diametrics Medical Ltd, High Wycombe, UK).
Methods: Liver tissue oxygenation was measured in anaesthetized patients undergoing liver resection using a sensor inserted under the liver capsule. PtO2 and PtCO2 were recorded with FIO2 values of 0.3 and 1.0, at end-tidal carbon dioxide partial pressures of 3.5 and 4.5 kPa and 10 min after the onset of liver ischaemia (Pringle manoeuvre).
Results: Data are expressed as median (interquartile range). Increasing the FIO2 from 0.3 to 1.0 resulted in the PtO2 changing from 4.1 (2.6-5.4) to 4.6 (3.8-5.2) kPa, but this was not significant. During the 10 min period of ischaemia PtCO2 increased significantly (P<0.05) from 6.7 (5.8-7.0) to 11.5 (9.7-15.3) kPa and PtO2 decreased, but not significantly, from 4.3 (3.5-12.0) to 3.3 (0.9-4.1) kPa.
Conclusion: PtO2 and PtCO2 were measured directly using a Paratrend sensor in human liver tissue. During anaesthesia, changes in ventilation and liver blood flow caused predictable changes in PtCO2.