Defense mechanisms to increasing back pressure for hepatic oxygen transport and venous return in porcine fecal peritonitis.

High central venous pressure (CVP) acutely decreases venous return. How this affects hepatic oxygen transport in sepsis remains unclear. The aim of this study was to evaluate the effects of repeated increases in CVP via standard nursing procedures (NPs) on hepato-splanchnic and renal oxygen transport in a prolonged porcine sepsis model. Twenty anesthetized and mechanically ventilated pigs with regional hemodynamics monitored were randomized to fecal peritonitis or controls (n = 10 pigs/group). Resuscitation was started after 8 h of observation and continued for 3 days. NPs were performed at baseline and 8 h, 32 h, 56 h, and 72 h after resuscitation started. NPs increased CVP by 4-7 mmHg in both groups. In controls, this was associated with less decrease in hepatic arterial (Qha; 62 ± 70 mL/min) than portal venous flow (Qpv; 364 ± 151 mL/min). Portal venous oxygen content and hepatic O2 delivery (Do2) and consumption (V̇o2) decreased by 11 ± 6 mL/dL and 0.9 ± 0.3 and 0.4 ± 0.3 mL·min-1·kg-1, respectively. In septic animals, hepatic Do2 decreased more in response to increasing CVP (1.5 ± 0.9 mL·min-1·kg-1), which was attributable to a larger fall in both Qha (88 ± 66 ml/min) and portal O2 content (14 ± 10 mL/dL, all P < 0.05). This resulted in numerically lower hepatic V̇o2 since O2 extraction did not increase significantly. In control conditions, a smaller decrease in Qha compared with Qpv helped to limit the reduction in hepatic V̇o2 in response to acute CVP increase. In sepsis, the contribution of Qha to maintain hepatic Do2 was reduced, which jeopardized hepatic V̇o2 further. Renal arterial flow was similarly affected by CVP increase as Qha.NEW & NOTEWORTHY Sepsis impairs intrinsic mechanisms to attenuate effects of increasing back pressure on hepatic oxygen transport.

Defining and treating acute kidney injury patients in Brazilian intensive care units: Results from a cross-sectional nationwide survey.

PURPOSE: The purpose of the study is to characterize the practices of Brazilian intensivists toward acute kidney injury (AKI) definition and management. METHODS: A cross-sectional survey was conducted among 36 Brazilian hospitals. RESULTS: Of 731 ICU physicians invited to participate, 310 (42%) responded to the survey. Nearly half of the intensive care unit (ICU) physicians (146/310) do not apply AKIN and/or RIFLE definitions to their ICU patients. Most of the respondents prescribe intravenous fluids as a first-line therapeutic intervention for AKI patients. Although 38% of the surveyed physicians considered worsening of respiratory parameters to be the main criterion for stopping fluid infusion, only 15% considered daily net fluid balance as a criterion. Most of the respondents believed in the benefits of early renal replacement therapy (RRT) and considered worsening acidosis the most important criteria for starting early RRT. The main reason for a nephrologist referral was an urgently needed RRT. CONCLUSIONS: Despite recent advances in AKI definition and management, most of the surveyed ICU physicians in Brazil have not incorporated them in their clinical practice. Important differences in the management of AKI patients were observed among Brazilian ICU physicians, which is relevant for educational interventions and future research.