The Impact of Renal Failure and Renal Replacement Therapy on Outcome During Extracorporeal Membrane Oxygenation Therapy.

Acute kidney injury (AKI) is common in patients treated with veno-arterial (VA-) or veno-venous (VV-) extracorporeal membrane oxygenation (ECMO). In this setting, the use of continuous renal replacement therapy (CRRT) can help to optimize fluid status but may also negatively impact on patients' outcome. In contrast, the relationship between AKI, CRRT, and survival in critically ill adult patients receiving ECMO is not well defined. The institutional ECMO database (n = 162) from November 2008 to December 2013, excluding patients with ICU survival <24 hours was reviewed. Demographics, co-morbidities, and concomitant therapies for all patients were collected. AKI was defined according to the Acute Kidney Injury Network (AKIN) criteria. ICU mortality was noted. Data were retrieved for 135 patients (79 with VA-ECMO and 56 with VV-ECMO). Of these, 95 developed AKI, 63 (47%) of whom required CRRT; thus three groups of patients were identified: (a) no AKI; (b) AKI without CRRT (AKINOCRRT ); and (c) CRRT with AKI (AKICRRT ). AKINOCCRT patients were more likely to have preexisting heart disease, to be more severely ill, and to be treated with VA-ECMO than those without AKI. AKICRRT patients were also more likely to be treated with VA-ECMO, had more organ dysfunction at the time of ECMO insertion, and needed more transfusions and inotropic agents than patients without AKI. ICU mortality was 53% (72/135) and was similar in the three groups, even when different AKI stages or VA/VV-ECMO were analyzed separately. In this study, the use of CRRT was not associated with an increased mortality in an adult population of patients treated with ECMO, even after adjustment for confounders.

The Prognostic Value of 48-h Continuous EEG During Therapeutic Hypothermia After Cardiac Arrest.

BACKGROUND: The aim of this study was to evaluate the prognostic value of continuous electroencephalogram (cEEG) during the first 48 h following cardiac arrest (CA) in patients treated with targeted temperature management (TTM). METHODS: We reviewed data from 92 comatose post-CA patients over a 6 year-period; cEEG recordings were performed during TTM and restoration of normothermia. EEG findings were divided into four time-periods: 0-8, 8-16, 16-24, and 24-48 h after CA. Background EEG findings were defined as moderate encephalopathy (diffuse slowing with reactivity/variability), severe encephalopathy (diffuse slowing without reactivity/variability), burst suppression or suppression, and dichotomized as malignant (suppression/burst suppression/severe encephalopathy) or benign (moderate encephalopathy). Epileptiform activity was defined as the presence of seizures, sporadic epileptiform discharges, or periodic discharges. Neurological outcome was assessed at 3 months using the cerebral performance categories (CPC) score (good outcome: CPC 1-2). RESULTS: 26/92 (28%) patients had a good outcome. Malignant patterns were associated with a poor outcome at all time-points, with a high positive predictive value (94-97%) but a poor negative predictive value (44-56%). Epileptiform activity did not influence the prognostic value of EEG patterns. All patients with moderate encephalopathy and seizures or generalized periodic discharges had a poor outcome. CONCLUSIONS: cEEG can identify patients with poor outcome from the first hours following CA, with limited predictive value for good outcome. Epileptiform activity did not improve the prognostic accuracy of EEG, but seizures and generalized periodic discharges were associated with poor outcome even when developing on a benign EEG pattern.

How much oxygen in adult cardiac arrest?

Although experimental studies have suggested that a high arterial oxygen pressure (PaO2) might aggravate post-anoxic brain injury, clinical studies in patients resuscitated from cardiac arrest (CA) have given conflicting results. Some studies found that a PaO2 of more than 300 mm Hg (hyperoxemia) was an independent predictor of poor outcome, but others reported no association between blood oxygenation and neurological recovery in this setting. In this article, we review the potential mechanisms of oxygen toxicity after CA, animal data available in this field, and key human studies dealing with the impact of oxygen management in CA patients, highlighting some potential confounders and limitations and indicating future areas of research in this field. From the currently available literature, high oxygen concentrations during cardiopulmonary resuscitation seem preferable, whereas hyperoxemia should be avoided in the post-CA care. A specific threshold for oxygen toxicity has not yet been identified. The mechanisms of oxygen toxicity after CA, such as seizure development, reactive oxygen species production, and the development of organ dysfunction, need to be further evaluated in prospective studies.

The potential role of auditory evoked potentials to assess prognosis in comatose survivors from cardiac arrest.

AIM: Few data are available on the use of brainstem auditory evoked potentials (BAEPs) in combination with other electrophysiological tools to assess prognosis of comatose survivors from cardiac arrest (CA). METHODS: Retrospective analysis of data from all adult patients (>18years of age) admitted to our Dept of Intensive Care after CA over a 6-year period who were comatose (Glasgow Coma Scale <9) on admission, had been treated with targeted temperature management and had BAEP testing. We collected variables related to CA, as well as electroencephalography (EEG) findings, N20 somatosensory evoked potentials, and the presence of I, III and/or V waves on BAEP testing. Outcome was assessed at 3 months using the Cerebral Performance Categories (3-5=poor outcome). RESULTS: We studied 65 patients; 48 (74%) had a poor neurological outcome. BAEP assessment was performed day 3 [3,4] after the CA. At least one of the three waves was absent bilaterally in 34 patients (52%); of these patients, 29 (85%) had a poor neurological outcome (sensitivity 60%, specificity 71%, positive predictive value [PPV] 85% and negative predictive value [NPV] 39%). Three patients (5%) had bilateral absence of all three waves, all of whom had a poor neurological outcome. CONCLUSIONS: In this series of patients after CA, at least one of the BAEP waves was absent bilaterally in half the survivors; however, their use for prediction of poor neurological outcome remains limited.

Altered liver function in patients undergoing veno-arterial extracorporeal membrane oxygenation (ECMO) therapy.

BACKGROUND: Multiple organ dysfunction can occur in patients undergoing Veno-arterial Extra Corporal Membrane Oxygenation (VA-ECMO); however, liver function has not been well studied in this setting. METHODS: In a review of our institutional ECMO database (n=162), we collected aspartate (AST) and alanine (ALT) transaminases, total bilirubin and international normalized ratio (INR) at time of ECMO initiation (baseline) and once daily during therapy in patients who survived for at least 24 hours. Elevated liver enzymes (ELE) were defined if AST and/or ALT were > 200 UI/L, and acute liver failure (ALF) as the presence of an INR ≥ 1.5, new onset encephalopathy and an elevated total bilirubin concentrations. RESULTS: On a total of 80 patients undergoing VA-ECMO, 69 patients met the inclusion criteria (cardiogenic shock, n=52; refractory cardiac arrest, n=15; cardiac failure following severe ARDS, n=2). Of them, 45 (65%) had early ELE after ECMO initiation (median highest AST and ALT were 528 [251-2606] UI/L and 513 [130-1031] UI/L, respectively). Two thirds of patients with ELE (N = 30) had a progressive reduction in AST and ALT, but the levels were normalized only after 5 [5-6] days. Among patients with ELE, 21/45 (47%) had AST and/or ALT levels above > 1000 UI/L. A total of 14/69 (20%) patients developed ALF. However, mortality rate was not significantly higher in patients with ELE or ALF when compared to others. CONCLUSIONS: A substantial proportion of patients needing VA-ECMO have early ELE, which usually improves over days. The prognostic implications are not evident.

Prognostic implications of blood lactate concentrations after cardiac arrest: a retrospective study.

BACKGROUND: Elevated lactate concentration has been associated with increased mortality after out-of-hospital cardiac arrest (CA). We investigated the variables associated with high blood lactate concentrations and explored the relationship between blood lactate and neurological outcome in this setting. METHODS: This was a retrospective analysis of an institutional database that included all adult (> 18 years) patients admitted to a multidisciplinary Department of Intensive Care between January 2009 and January 2013 after resuscitation from CA. Blood lactate concentrations were collected at hospital admission and 6, 12, 24 and 48 h thereafter. Neurological outcome was evaluated 3 months post-CA using the Cerebral Performance Category (CPC) score: a CPC of 3-5 was used to define a poor outcome. RESULTS: Of the 236 patients included, 162 (69%) had a poor outcome. On admission, median lactate concentrations (5.3[2.9-9.0] vs. 2.5[1.5-5.5], p < 0.001) and cardiovascular sequential organ failure assessment (cSOFA) score (3[0-4] vs. 0[0-3], p = 0.003) were higher in patients with poor than in those with favourable outcomes. Lactate concentrations were higher in patients with poor outcomes at all time points. Lactate concentrations were similar in patients with out-of-hospital and in-hospital CA at all time points. After adjustment, high admission lactate was independently associated with a poor neurological outcome (OR 1.18, 95% CI 1.08-1.30; p < 0.001). In multivariable analysis, use of vasopressors and high PaO2 on admission, longer time to return of spontaneous circulation and altered renal function were associated with high admission lactate concentrations. CONCLUSIONS: High lactate concentrations on admission were an independent predictor of poor neurological recovery post-CA, but the time course was not related to outcome. Prolonged resuscitation, use of vasopressors, high PaO2 and altered renal function were predictors of high lactate concentrations.

Greater temperature variability is not associated with a worse neurological outcome after cardiac arrest.

AIM: Spontaneous alterations in temperature homeostasis after cardiac arrest (CA) are associated with worse outcome. However, it remains unclear the prognostic role of temperature variability (TV) during cooling procedures. We hypothesized that low TV during targeted temperature management (TTM) would be associated with a favourable neurological outcome after CA. METHODS: We reviewed data from all comatose patients after in-hospital or out-of-hospital CA admitted to our Department of Intensive Care between December 2006 and January 2014 who underwent TTM (32-34°C) and survived at least 24h. We collected demographic data, CA characteristics, intensive care unit (ICU) survival and neurological outcome at three months (favourable neurological outcome was defined as cerebral performance category 1-2). TV was expressed using the standard deviation (SD) of all temperature measurements during hypothermia; high TV was defined as an SD >1°C. RESULTS: Of the 301 patients admitted over the study period, 72 patients were excluded and a total of 229 patients were studied; 88 had a favourable neurological outcome. The median temperature on ICU admission was 35.8 [34.9-36.9]°C and the median time to hypothermia (body temperature <34°C), was 4 [3-7] h. Median TV was 0.9 [0.6-1.0]°C and 57 patients (25%) had high TV. In multivariable logistic regression, witnessed CA, ventricular fibrillation/tachycardia and previous neurological disease were independent risk factors for high TV. Younger age, bystander cardiopulmonary resuscitation, shorter time to return of spontaneous circulation, cardiac origin of arrest, shockable rhythm and longer time to target temperature were independent predictors of favourable neurological outcome, but TV was not. CONCLUSIONS: Among comatose survivors treated with TTM after CA, 25% of patients had high TV; however, this was not associated with a worse neurologic outcome.