Correlation between LiMON^®-derived liver function parameters and classic liver function tests, intra-abdominal pressure (IAP) and organ failure in mixed ICU patients

Introduction

Indocyaninegreen (ICG) clearance can be measured with the LiMON^® device (Pulsion, Germany) and is expressed by the plasma disappearance rate (PDR) for ICG (normal value 18–25%) and the residual ICG after 15 min (R15, normal value 0–10%). In this study we investigated the correlation between PDR/R15 and IAP, SOFA score, and classic liver function tests in mixed ICU patients.

Methods

A total of 130 paired measurements were performed in 28 patients. The IAP was obtained using a balloon-tipped stomach catheter connected to an IAP monitor (Spiegelberg, Germany). The male/female ratio was 3/2, age was 58.2 ± 12.1 years, APACHE II score was 25.8 ± 15.7, SAPS II score was 44.4 ± 13.9, MODS was 6.4 ± 3, and SOFA score was 6.9 ± 3.6. The number of measurements in each patient was 4.6 ± 3.6. Calculation of correlation was performed with the Prism GraphPad™ software (version 2.00, 31 October 1995), and values are presented as mean ± SD.

Results

The values for IAP were 10 ± 4 mmHg (normal value 0–5 mmHg), PDR was 13.6 ± 8.4%, and R15 was 22.3 ± 19.8%. The correlation between IAP and PDR/R15 was poor although significant (R = 0.4), as was the correlation between PDR/R15 and the classic liver test (with R < 0.1): aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, gammaglutamyl transferase, alkaline phosphatase, or venous NH₃. From the so- called liver synthesis function tests, albumin, bilirubin, plasma cholinesterase levels and prothrombin time, only the latter had a good correlation. Neither platelets nor general hemodynamic parameters or lactate were well correlated. A significant and reasonable correlation was observed between PDR/R15 and SOFA score and the number of organ failures. Finally, the correlation between PDR and R15 was good (R = 0.8). Mortality was 57%, PDR was significantly lower (10.4 ± 5.7 vs 16.3 ± 6.6) in patients who died, while IAP (10.6 ± 3.9 vs 8.6 ± 3.6), SOFA score (13 ± 3.3 vs 7.7 ± 3.4) and number of organ failures (2.5 ± 1.1 vs 1.2 ± 0.9) were significantly higher. The number of measurement failures was 14% before and 3% after the software upgrade.

Conclusions

LiMON^® measurements are feasible at the bedside. There is no correlation between LiMON^®-derived parameters and the classic liver function tests except coagulation. Correlation with IAP was significant but poor. LiMON^®-derived parameters correlated with SOFA score and number of organ failures and give additional information. The PDR was lower in patients who died while IAP, SOFA and organ failures were higher.

Figure 1