Objective It has been suggested that fluid accumulation may delay recognition of acute kidney injury (AKI). We sought to determine the impact of fluid balance on the incidence of non-dialysis requiring AKI in patients with acute lung injury and to describe associated outcomes, including mortality. Design Analysis of the Fluid and Catheter Treatment Trial, a factorial randomized clinical trial of conservative versus liberal fluid management and of management guided by a central venous versus pulmonary artery catheter. Setting and Patients 1000 patients at ARDS Network hospitals. Measurements and Main Results The incidence of AKI, defined as an absolute rise in creatinine of ≥ 0.3 mg/dL or a relative change of > 50% over 48 hours, was examined before and after adjustment of serum creatinine for fluid balance. The incidence of AKI before adjustment for fluid balance was greater in those managed with the conservative fluid protocol (57 versus 51%, p = 0.04). After adjustment for fluid balance, the incidence of AKI was greater in those managed with the liberal fluid protocol (66 versus 58%, p = 0.007). Patients who met AKI criteria after adjustment of creatinine for fluid balance (but not before) had a mortality rate that was significantly greater than those who did not meet AKI criteria both before and after adjustment for fluid balance (31 versus 12%, p < 0.001) and those who had AKI before but not after adjustment for fluid balance (31 versus 11%, p = 0.005). The mortality of those patients meeting AKI criteria after but not before adjustment for fluid balance was similar to patients with AKI both before and after adjustment for fluid balance (31% versus 38%, p = 0.18). Conclusions Fluid management influences serum creatinine and therefore the diagnosis of AKI using creatinine-based definitions. Patients with “unrecognized” AKI that is identified after adjusting for positive fluid balance have high mortality rates, and patients who have AKI before but not after adjusting for fluid balance have low mortality rates. Future studies of AKI should consider potential differences in serum creatinine caused by changes in fluid balance and the impact of these differences on diagnosis and prognosis.

Rationale: Microvascular injury, inflammation, and coagulation play critical roles in the pathogenesis of acute lung injury (ALI). Plasma protein C levels are decreased in patients with acute lung injury and are associated with higher mortality and fewer ventilator-free days. Objectives: To test the efficacy of activated protein C (APC) as a therapy for patients with ALI. Methods: Eligible subjects were critically ill patients who met the American/European consensus criteria for ALI. Patients with severe sepsis and an APACHE II score of 25 or more were excluded. Participants were randomized to receive APC (24 mg/kg/h for 96 h) or placebo in a double-blind fashion within 72 hours of the onset of ALI. The primary endpoint was ventilator-free days. Measurements and Main Results: APC increased plasma protein C levels (P 5 0.002) and decreased pulmonary dead space fraction (P 5 0.02). However, there was no statistically significant difference between patients receiving placebo (n 5 38) or APC (n 5 37) in the number of ventilator-free days (median [25-75% interquartile range]: 19 [0-24] vs. 19 [14-22], respectively; P 5 0.78) or in 60-day mortality (5/38 vs. 5/37 patients, respectively; P 5 1.0). There were no differences in the number of bleeding events between the two groups. Conclusions: APC did not improve outcomes from ALI. The results of this trial do not support a large clinical trial of APC for ALI in the absence of severe sepsis and high disease severity. Clinical trial registered with www.clinicaltrials.gov (NCT 00112164).

Exposure of human alveolar macrophages to bacterial LPS results in activation of a number of signal transduction pathways. An early event after the alveolar macrophage comes in contact with LPS is activation of the phosphatidylinositol 3 kinase (PI 3-kinase). This study evaluates the downstream effects of that activation. We observed that LPS exposure results in phosphorylation of Akt (serine 473). We found this using both phosphorylation-specific Abs and also by in vivo phosphorylation with 32P-loaded cells. AKT activation resulted in the phosphorylation-dependent inactivation of glycogen synthase kinase (GSK-3) (serine 21/9). We found that both of these events were linked to PI 3-kinase because the PI 3-kinase inhibitors, wortmannin and LY294002, inhibited LPS-induced phosphorylation of both AKT and GSK-3. Inactivation of GSK-3 has been shown to reduce the ubiquitination of β-catenin, resulting in nuclear accumulation and transcriptional activity of β-catenin. Consistent with this, we found that LPS caused an increase in the amounts of PI 3-kinase-dependent nuclear β-catenin in human alveolar macrophages and expression of genes that require nuclear β-catenin for their activation. This is the first demonstration that LPS exposure activates AKT, inactivates GSK-3, and causes accumulation and transcriptional activity of β-catenin in the nucleus of any cell, including alveolar macrophages.

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Human alveolar macrophages respond to endotoxin (LPS) by activation of a number of mitogen-activated protein kinase pathways, including the p42/44 (extracellular signal-related kinase (ERK)) kinase pathway. In this study, we evaluated the role of the atypical protein kinase C (PKC) isoform, PKC ζ, in LPS-induced activation of the ERK kinase pathway. Kinase activity assays showed that LPS activates PKC ζ, mitogen-activated protein/ERK kinase (MEK, the upstream activator of ERK), and ERK. LPS did not activate Raf-1, the classic activator of MEK. Pseudosubstrate-specific peptides with attached myristic acid are cell permeable and can be used to block the activity of specific PKC isoforms in vivo. We found that a peptide specific for PKC ζ partially blocked activation of both MEK and ERK by LPS. We also found that this peptide blocked in vivo phosphorylation of MEK after LPS treatment. In addition, we found that LPS caused PKC ζ to bind to MEK in vivo. These observations suggest that MEK is an LPS-directed target of PKC ζ. PKC ζ has been shown in other systems to be phosphorylated by phosphatidylinositol (PI) 3-kinase-dependent kinase. We found that LPS activates PI 3-kinase and causes the formation of a PKC ζ/PI 3-kinase-dependent kinase complex. These data implicate the PI 3-kinase pathway as an integral part of the LPS-induced PKC ζ activation. Taken as a whole, these studies suggest that LPS activates ERK kinase, in part, through activation of an atypical PKC isoform, PKC ζ.

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Family members, clinicians, and experts identified specific communication behaviors that clinicians should use to discuss prognosis in the critical care setting. These findings extend existing opinion-based recommendations and should guide interventions to improve communication about prognosis in ICUs.