Mortality in patients with hepatic gas on point-of-care ultrasound in cardiac arrest: Does location matter?

PURPOSE: Prior research has suggested an association of hepatic venous gas with mortality in cardiac arrest. As point of care ultrasound (POCUS) is frequently used in the context of resuscitation, we sought to evaluate if the presence of hepatic gas on POCUS had a similar mortality association. METHODS: A retrospective review was conducted of patients who experienced nontraumatic cardiac arrest. Archived ultrasound images were independently reviewed to determine the presence of gas in the hepatic parenchyma and vasculature. Electronic medical records were then reviewed to collect remaining clinical data. RESULTS: From 1 January 2017 through 16 June 2019, 87 patients met inclusion criteria. Among them, 68 (78.2%) patients died. Among those who died, 40 (58.8%) had hepatic gas, while 28 (41.2%) had none. Only a single survivor demonstrated hepatic venous gas (11%). While the difference in mortality with respect to presence of undifferentiated hepatic gas was not significant (P = .37), there was a significant difference with respect to the presence of venous gas (P = .004). CONCLUSION: Our study demonstrated that the incidence of postarrest hepatic gas on POCUS was common, and that the presence of hepatic venous gas during cardiac resuscitation was associated with increased mortality, while hepatic parenchymal gas alone was not.

Nanoparticle-macrophage interactions: A balance between clearance and cell-specific targeting.

The surface properties of nanoparticles (NPs) are a major factor that influences how these nanomaterials interact with biological systems. Interactions between NPs and macrophages of the reticuloendothelial system (RES) can reduce the efficacy of NP diagnostics and therapeutics. Traditionally, to limit NP clearance by the RES system, the NP surface is neutralized with molecules like poly(ethylene glycol) (PEG) which are known to resist protein adsorption and RES clearance. Unfortunately, PEG modification is not without drawbacks including difficulties with the synthesis and associations with immune reactions. To overcome some of these obstacles, we neutralized the NP surface by acetylation and compared this modification to PEGylation for RES clearance and tumor-specific targeting. We found that acetylation was comparable to PEGylation in reducing RES clearance. Additionally, we found that dendrimer acetylation did not impact folic acid (FA)-mediated targeting of tumor cells whereas PEG surface modification reduced the targeting ability of the NP. These results clarify the impact of different NP surface modifications on RES clearance and cell-specific targeting and provide insights into the design of more effective NPs.