Cerebral oxygen saturation in cirrhotic patients with gastro-intestinal bleeding, a near infrared spectroscopy study

Abstract

Near Infrared Spectroscopy (NIRS) is a non-invasive optical technique allowing a continuous measurement of brain's hemoglobin (Hb) saturation in oxygen (rSO2). It is a marker of cerebral insult and rSO2 < 50% is associated with increased neurological impairment. Cirrhotic patients with gastrointestinal bleeding (GIB) often develop hepatic encephalopathy (HE). The aims of this study were: (1) to assess brain oxygenation using NIRS in cirrhotic patients with GIB, (2) to determine if brain oxygenation was correlated to Hb level, blood pressure and liver function (3) if brain oxygenation was influencing the occurrence of HE and survival. Cirrhotic patients admitted to ICU for GIB were prospectively included and compared to non-cirrhotic patients. Bilateral recording of rSO2 was started upon admission using an INVOS 5100c Cerebral Oxymeter (Covidien). Initial, minimal, average rSO2 and AUC of rSO2 < 50% (AUC50% rSO2) were extracted. Sixty-one cirrhotic and 14 non-cirrhotic patients were included. Child-Pugh score was at 9.5 ± 0.3 and MELD score was 17.8 ± 0.9. None of the NIRS parameters differed between cirrhotic and non-cirrhotic patients. Thirty-nine patients (64%) among the 61 cirrhotic and 10 (71%) among the 14 non-cirrhotic patients displayed an initial rSO2 below the 50% threshold at least on one side. NIRS parameters correlated mainly with Hb level and MELD but not with MAP or PaO2. There was no significant correlation between NIRS parameters and survival or HE upon admission, within 5 days and after discharge. Patients with GIB frequently present rSO2 below the threshold of 50%. The significance of this finding is uncertain since it does not seem clearly correlated to a poor outcome in ICU or in the follow-up.

Keywords: Cerebral oxygenation; Cirrhosis; Gastrointestinal bleeding; Hepatic encephalopathy; Near infrared spectroscopy.