Acid–base disturbances are frequently observed in critically ill patients at the intensive care unit. To our knowledge, the acid–base profile of patients with acute-on-chronic liver failure (ACLF) has not been evaluated and compared to critically ill patients without acute or chronic liver disease. One hundred and seventy-eight critically ill patients with liver cirrhosis were compared to 178 matched controls in this post hoc analysis of prospectively collected data. Patients with and without liver cirrhosis showed hyperchloremic acidosis and coexisting hypoalbuminemic alkalosis. Cirrhotic patients, especially those with ACLF, showed a marked net metabolic acidosis owing to increased lactate and unmeasured anions. This metabolic acidosis was partly antagonized by associated respiratory alkalosis, yet with progression to ACLF resulted in acidemia, which was present in 62% of patients with ACLF grade III compared to 19% in cirrhosis patients without ACLF. Acidemia and metabolic acidosis were associated with 28-day mortality in cirrhosis. Patients with pH values < 7.1 showed a 100% mortality rate. Acidosis attributable to lactate and unmeasured anions was independently associated with mortality in liver cirrhosis. Cirrhosis and especially ACLF are associated with metabolic acidosis and acidemia owing to lactate and unmeasured anions. Acidosis and acidemia, respectively, are associated with increased 28-day mortality in liver cirrhosis. Lactate and unmeasured anions are main contributors to metabolic imbalance in cirrhosis and ACLF.

Hypoxic hepatitis (HH) is a frequent and potentially life-threatening event typically occurring in critically ill patients as a consequence of hemodynamic impairment. While acute kidney injury (AKI) has been well described in patients with acute liver failure, incidence and outcome of AKI accompanying HH are unclear. The aim of this study was to assess incidence, clinical implications and outcome of AKI and renal replacement therapy (RRT) in critically ill patients with HH. A total of 1948 consecutive critically ill admissions were studied at the Medical University of Vienna. Laboratory and clinical parameters as well as the presence of HH and AKI were assessed on a daily basis. Outcome, renal recovery and length of stay were assessed and documented, and patients were followed for 1 year. A total of 295 admissions (15 %) developed HH. Main precipitators were cardiogenic (44 %) and septic shock (36 %). Occurrence of HH was significantly associated with AKI [OR 4.50 (95 % CI 3.30–6.12)] and necessity of renal replacement therapy [RRT; OR 3.36 (95 % CI 2.58–4.37)], p < 0.001 for both. Two hundred forty admissions with HH (81 %) developed AKI, 159 of whom (66 %) had AKI stage 3. Both HH and AKI were significantly linked to mortality. AKI stage 3, international normalized ratio (INR, during HH) and the presence of septic shock were identified as independent predictors of 28-day mortality in admissions with HH, whereas RRT was identified as an independent protective factor. There was a synergistic effect of HH and AKI on length of stay at the ICU. Of all HH survivors treated with RRT, 71 % showed renal recovery during follow-up. HH is frequently complicated by occurrence of AKI. Severity of HH, AKI stage and the presence of septic shock seem to contribute to poor outcome in these patients. Initiation of RRT in HH with AKI may enable renal recovery and should not be withheld in medical ICU patients.

Introduction: Critical illness leads to increased endogenous production of carbon monoxide (CO) due to the induction of the stress-response enzyme, heme oxygenase-1 (HO-1). There is evidence for the cytoprotective and anti-inflammatory effects of CO based on animal studies. In critically ill patients after cardiothoracic surgery, low minimum and high maximum carboxyhemoglobin (COHb) levels were shown to be associated with increased mortality, which suggests that there is an 'optimal range' for HO-1 activity. Our study aimed to test whether this relationship between COHb and outcome exists in non-surgical ICU patients. Methods: We conducted a retrospective, observational study in a medical ICU at a university hospital in Vienna, Austria involving 868 critically ill patients. No interventions were undertaken. Arterial COHb was measured on admission and during the course of treatment in the ICU. The association between arterial COHb levels and ICU mortality was evaluated using bivariate tests and a logistic regression model. Results: Minimum COHb levels were slightly lower in non-survivors compared to survivors (0.9%, 0.7% to 1.2% versus 1.2%, 0.9% to 1.5%; P = 0.0001), and the average COHb levels were marginally lower in non-survivors compared to survivors (1.5%, 1.2% to 1.8% versus 1.6%, 1.4% to 1.9%, P = 0.003). The multivariate logistic regression analysis revealed that the association between a low minimum COHb level and increased mortality was independent of the severity of illness and the type of organ failure. Conclusions: Critically ill patients surviving the admission to a medical ICU had slightly higher minimum and marginally higher average COHb levels when compared to non-survivors. Even though the observed differences are statistically significant, the minute margins would not qualify COHb as a predictive marker for ICU mortality.

Refeeding syndrome (RFS) is a potentially life-threatening complication in malnourished (critically ill) patients. The presence of various accepted RFS definitions and the inclusion of heterogeneous patient populations in the literature has led to discrepancies in reported incidence rates in patients requiring treatment at an intensive care unit (ICU). We conducted a prospective observational study from 2010 to 2013 to assess the RFS incidence and clinical characteristics among medical ICU patients at a large tertiary center. RFS was defined as a decrease of more than 0.16 mmol/L serum phosphate to values below 0.65 mmol/L within seven days after the start of medical nutrition therapy or pre-existing serum phosphate levels below 0.65 mmol/L. Overall, 195 medical patients admitted to the ICU were included. RFS was recorded in 92 patients (47.18%). The presence of RFS indicated significantly altered phosphate and potassium levels and was accompanied by significantly more electrolyte substitutions (phosphate, potassium, and magnesium). No differences in fluid balance, energy delivery, and insulin requirements were detected. The presence of RFS had no impact on ICU length of stay and ICU mortality. Screening for RFS using simple diagnostic criteria based on serum phosphate levels identified critically ill patients with an increased demand for electrolyte substitutions. Therefore, stringent monitoring of electrolyte levels is indicated to prevent life-threatening complications.

Patients on extracorporeal membrane oxygenation are frequently in need for sedation. Use of propofol has been associated with impaired oxygenator function due to adsorption to the membrane as well as lipid load. The aim of our retrospective analysis was to compare two different sedation regimens containing either propofol or midazolam with respect to oxygenator running time. Midazolam was used in 73 patients whereas propofol was used in 49 patients, respectively. In the propofol group, veno-arterial–extracorporeal membrane oxygenation was used predominantly (84%), while veno-venous–extracorporeal membrane oxygenation was used more often in the midazolam group (64%). Oxygenator running time until first exchange was 7 days in both groups (p = 0.759). No statistically significant differences could be observed between the subgroup of patients receiving lipid-free (n = 24) and lipid-containing (n = 31) parenteral nutrition, respectively. Laboratory parameters like triglycerides, free hemoglobin, fibrinogen, platelets, and activated partial thromboplastin time were not significantly different between both sedation regimens (p = 0.462, p = 0.489, p = 0.960, p = 0.134, and p = 0.843) and were not associated with oxygenator running time. The use of propofol as sedative seems suitable in patients undergoing extracorporeal membrane oxygenation therapy.