Estimated Cerebral Perfusion Pressure and Intracranial Pressure in Septic Patients.

BACKGROUND: Sepsis-associated brain dysfunction (SABD) is frequent and is associated with poor outcome. Changes in brain hemodynamics remain poorly described in this setting. The aim of this study was to investigate the alterations of cerebral perfusion pressure and intracranial pressure in a cohort of septic patients. METHODS: We conducted a retrospective analysis of prospectively collected data in septic adults admitted to our intensive care unit (ICU). We included patients in whom transcranial Doppler recording performed within 48 h from diagnosis of sepsis was available. Exclusion criteria were intracranial disease, known vascular stenosis, cardiac arrhythmias, pacemaker, mechanical cardiac support, severe hypotension, and severe hypocapnia or hypercapnia. SABD was clinically diagnosed by the attending physician, anytime during the ICU stay. Estimated cerebral perfusion pressure (eCPP) and estimated intracranial pressure (eICP) were calculated from the blood flow velocity of the middle cerebral artery and invasive arterial pressure using a previously validated formula. Normal eCPP was defined as eCPP ≥ 60 mm Hg, low eCPP was defined as eCPP < 60 mm Hg; normal eICP was defined as eICP ≤ 20 mm Hg, and high eICP was defined as eICP > 20 mm Hg. RESULTS: A total of 132 patients were included in the final analysis (71% male, median [interquartile range (IQR)] age was 64 [52-71] years, median [IQR] Acute Physiology and Chronic Health Evaluation II score on admission was 21 [15-28]). Sixty-nine (49%) patients developed SABD during the ICU stay, and 38 (29%) were dead at hospital discharge. Transcranial Doppler recording lasted 9 (IQR 7-12) min. Median (IQR) eCPP was 63 (58-71) mm Hg in the cohort; 44 of 132 (33%) patients had low eCPP. Median (IQR) eICP was 8 (4-13) mm Hg; five (4%) patients had high eICP. SABD occurrence and in-hospital mortality did not differ between patients with normal eCPP and patients with low eCPP or between patients with normal eICP and patients with high eICP. Eighty-six (65%) patients had normal eCPP and normal eICP, 41 (31%) patients had low eCPP and normal eICP, three (2%) patients had low eCPP and high eICP, and two (2%) patients had normal eCPP and high eICP; however, SABD occurrence and in-hospital mortality were not significantly different among these subgroups. CONCLUSIONS: Brain hemodynamics, in particular CPP, were altered in one third of critically ill septic patients at a steady state of monitoring performed early during the course of sepsis. However, these alterations were equally common in patients who developed or did not develop SABD during the ICU stay and in patients with favorable or unfavorable outcome.

Cerebral autoregulation in anoxic brain injury patients treated with targeted temperature management.

BACKGROUND: Little is known about the prevalence of altered CAR in anoxic brain injury and the association with patients' outcome. We aimed at investigating CAR in cardiac arrest survivors treated by targeted temperature management and its association to outcome. METHODS: Retrospective analysis of prospectively collected data. INCLUSION CRITERIA: adult cardiac arrest survivors treated by targeted temperature management (TTM). EXCLUSION CRITERIA: trauma; sepsis, intoxication; acute intra-cranial disease; history of supra-aortic vascular disease; severe hemodynamic instability; cardiac output mechanical support; arterial carbon dioxide partial pressure (PaCO2) > 60 mmHg; arrhythmias; lack of acoustic window. Middle cerebral artery flow velocitiy (FV) was assessed by transcranial Doppler (TCD) once during hypothermia (HT) and once during normothermia (NT). FV and blood pressure (BP) were recorded simultaneously and Mxa calculated (MATLAB). Mxa is the Pearson correlation coefficient between FV and BP. Mxa > 0.3 defined altered CAR. Survival was assessed at hospital discharge. Cerebral Performance Category (CPC) 3-5 assessed 3 months after CA defined unfavorable neurological outcome (UO). RESULTS: We included 50 patients (Jan 2015-Dec 2018). All patients had out-of-hospital cardiac arrest, 24 (48%) had initial shockable rhythm. Time to return of spontaneous circulation was 20 [10-35] min. HT (core body temperature 33.7 [33.2-34] °C) lasted for 24 [23-28] h, followed by rewarming and NT (core body temperature: 36.9 [36.6-37.4] °C). Thirty-one (62%) patients did not survive at hospital discharge and 36 (72%) had UO. Mxa was lower during HT than during NT (0.33 [0.11-0.58] vs. 0.58 [0.30-0.83]; p = 0.03). During HT, Mxa did not differ between outcome groups. During NT, Mxa was higher in patients with UO than others (0.63 [0.43-0.83] vs. 0.31 [- 0.01-0.67]; p = 0.03). Mxa differed among CPC values at NT (p = 0.03). Specifically, CPC 2 group had lower Mxa than CPC 3 and 5 groups. At multivariate analysis, initial non-shockable rhythm, high Mxa during NT and highly malignant electroencephalography pattern (HMp) were associated with in-hospital mortality; high Mxa during NT and HMp were associated with UO. CONCLUSIONS: CAR is frequently altered in cardiac arrest survivors treated by TTM. Altered CAR during normothermia was independently associated with poor outcome.

Low hemoglobin and venous saturation levels are associated with poor neurological outcomes after cardiac arrest.

INTRODUCTION: Hemoglobin (Hb) is a main determinant of tissue oxygen delivery and anemia could be particularly harmful in post-anoxic brain injury. The aim of this study was to evaluate the association of Hb and venous Hb oxygen saturation (SvO2/ScvO2) with long-term neurological outcome in patients admitted after cardiac arrest (CA). METHODS: Analysis of adult CA patients admitted to the Department of Intensive Care of the Erasme University Hospital (Brussels, Belgium) over 9 years. We retrieved all data concerning CA characteristics as well as Hb during the first 48 h since injury as well as the need for red blood cells transfusions (RBCT). Minimum Hb and Hb oxygen saturation values were recorded. Neurological outcome was evaluated 3 months after CA. Unfavorable neurological outcome (UO) was defined as a Cerebral Performance Categories (CPC) score of 3-5. RESULTS: We treated 414 patients patients with CA, including 231 (56%) out-of-hospital cardiac arrest (OHCA) and 158 (38%) with an initial shockable rhythm. Median Hb concentration on admission was 12.0 [9.9-13.7] g/dL and the lowest Hb concentration was 10.0 [8.1-11.0] g/dL; 127 patients (31%) received at least one RBCT. Hb oxygen saturation on admission was 67 [59-74]%, while the lowest value was 60 [53-68]%. Low Hb and Hb oxygen saturation values were independently associated with UO; the optimal cut-off to predict UO was <9.9 g/dL and <60%, respectively. CONCLUSIONS: Low hemoglobin values and low values of oxygen venous saturation are significantly associated with unfavorable neurological outcome in adult patients resuscitated from cardiac arrest.

Comparison of estimation of cardiac output using an uncalibrated pulse contour method and echocardiography during veno-venous extracorporeal membrane oxygenation.

INTRODUCTION: During veno-venous extracorporeal membrane oxygenation, cardiac output monitoring is essential to assess tissue oxygen delivery. Adequate arterial oxygenation depends on the ratio between the extracorporeal pump blood flow and the cardiac output. The aim of this study was to compare estimates of cardiac output and blood flow/cardiac output ratios made using an uncalibrated pulse contour method with those made using echocardiography in patients treated with veno-venous extracorporeal membrane oxygenation. METHODS: Cardiac output was estimated simultaneously using a pulse contour method (MostCareUp; Vygon, Encouen, France) and echocardiography in 17 hemodynamically stable patients treated with veno-venous extracorporeal membrane oxygenation. Comparisons were made using Bland-Altman and linear regression analysis. RESULTS: There were significant correlations between cardiac output estimated using pulse contour method and echocardiography and between blood flow/cardiac output estimated using pulse contour method and blood flow/cardiac output estimated using echocardiography (r = 0.84, p < 0.001 and r = 0.87, p < 0.001, respectively). Bland-Altman analysis showed a good agreement (bias -0.20 ± 0.50 L/min) and a low percentage of error (25%) for the cardiac output values estimated by the two methods. The bias between the blood flow/cardiac output ratios obtained with the two methods was 5.19% ± 12.3% (percentage of error = 28.1%). CONCLUSIONS: The pulse contour method is a valuable alternative to echocardiography for the assessment of cardiac output and the blood flow/cardiac output ratio in patients treated with veno-venous extracorporeal membrane oxygenation.

Acute liver dysfunction after cardiac arrest.

Few data are available regarding hypoxic hepatitis (HH) and acute liver failure (ALF) in patients resuscitated from cardiac arrest (CA). The aim of this study was to describe the occurrence of these complications and their association with outcome. All adult patients admitted to the Department of Intensive Care following CA were considered for inclusion in this retrospective study. Exclusion criteria were early death (<24 hours) or missing biological data. We retrieved data concerning CA characteristics and markers of liver function. ALF was defined as a bilirubin >1.2 mg/dL and an international normalized ratio ≥1.5. HH was defined as an aminotransferase level >1000 IU/L. Neurological outcome was assessed at 3 months and an unfavourable neurological outcome was defined as a Cerebral Performance Categories (CPC) score of 3-5. A total of 374 patients (age 62 [52-74] years; 242 male) were included. ALF developed in 208 patients (56%) and HH in 27 (7%); 24 patients developed both conditions. Patients with HH had higher mortality (89% vs. 51% vs. 45%, respectively) and greater rates of unfavourable neurological outcome (93% vs. 60% vs. 59%, respectively) compared to those with ALF without HH (n = 184) and those without ALF or HH (n = 163; p = 0.03). Unwitnessed arrest, non-shockable initial rhythm, lack of bystander cardiopulmonary resuscitation, high adrenaline doses and the development of acute kidney injury were independent predictors of unfavourable neurological outcome; HH (OR: 16.276 [95% CIs: 2.625-81.345; p = 0.003), but not ALF, was also a significant risk-factor for unfavourable outcome. Although ALF occurs frequently after CA, HH is a rare complication. Only HH is significantly associated with poor neurological outcome in this setting.