Acid sphingomyelinase serum activity predicts mortality in intensive care unit patients after systemic inflammation: a prospective cohort study.
BACKGROUND
Acid sphingomyelinase is involved in lipid signalling pathways and regulation of apoptosis by the generation of ceramide and plays an important role during the host response to infectious stimuli. It thus has the potential to be used as a novel diagnostic marker in the management of critically ill patients. The objective of our study was to evaluate acid sphingomyelinase serum activity (ASM) as a diagnostic and prognostic marker in a mixed intensive care unit population before, during, and after systemic inflammation.


METHODS
40 patients admitted to the intensive care unit at risk for developing systemic inflammation (defined as systemic inflammatory response syndrome plus a significant procalcitonin [PCT] increase) were included. ASM was analysed on ICU admission, before (PCT before), during (PCT peak) and after (PCT low) onset of SIRS. Patients undergoing elective surgery served as control (N = 8). Receiver-operating characteristics curves were computed.


RESULTS
ASM significantly increased after surgery in the eight control patients. Patients from the intensive care unit had significantly higher ASM on admission than control patients after surgery. 19 out of 40 patients admitted to the intensive care unit developed systemic inflammation and 21 did not, with no differences in ASM between these two groups on admission. In patients with SIRS and PCT peak, ASM between admission and PCT before was not different, but further increased at PCT peak in non-survivors and was significantly higher at PCT low compared to survivors. Survivors exhibited decreased ASM at PCT peak and PCT low. Receiver operating curve analysis on discrimination of ICU mortality showed an area under the curve of 0.79 for ASM at PCT low.


CONCLUSIONS
In summary, ASM was generally higher in patients admitted to the intensive care unit compared to patients undergoing uncomplicated surgery. ASM did not indicate onset of systemic inflammation. In contrast to PCT however, it remained high in non-surviving ICU patients after systemic inflammation.
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Matthias
M
Kott
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Gunnar
G
Elke
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany; Institute of Immunology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Maike
M
Reinicke
Institute of Immunology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Supandi
S
Winoto-Morbach
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Dirk
D
Schädler
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Günther
G
Zick
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Inéz
I
Frerichs
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Norbert
N
Weiler
Institute of Immunology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Stefan
S
Schütze
D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007773:Lactates / Q000097:blood; D008297:Male; D010865:Pilot Projects; D011379:Prognosis; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D012372:ROC Curve; D012306:Risk; D013108:Sphingomyelin Phosphodiesterase / Q000097:blood*; D018746:Systemic Inflammatory Response Syndrome / Q000097:blood / Q000175:diagnosis / Q000201:enzymology* / Q000401:mortality*
C000606589:CALCA protein, human; D007773:Lactates; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D013108:Sphingomyelin Phosphodiesterase; D015740:Calcitonin Gene-Related Peptide