Incidence and management of metabolic acidosis with sodium bicarbonate in the ICU: An international observational study.

BACKGROUND: Metabolic acidosis is a major complication of critical illness. However, its current epidemiology and its treatment with sodium bicarbonate given to correct metabolic acidosis in the ICU are poorly understood. METHOD: This was an international retrospective observational study in 18 ICUs in Australia, Japan, and Taiwan. Adult patients were consecutively screened, and those with early metabolic acidosis (pH < 7.3 and a Base Excess < -4 mEq/L, within 24-h of ICU admission) were included. Screening continued until 10 patients who received and 10 patients who did not receive sodium bicarbonate in the first 24 h (early bicarbonate therapy) were included at each site. The primary outcome was ICU mortality, and the association between sodium bicarbonate and the clinical outcomes were assessed using regression analysis with generalized linear mixed model. RESULTS: We screened 9437 patients. Of these, 1292 had early metabolic acidosis (14.0%). Early sodium bicarbonate was given to 18.0% (233/1292) of these patients. Dosing, physiological, and clinical outcome data were assessed in 360 patients. The median dose of sodium bicarbonate in the first 24 h was 110 mmol, which was not correlated with bodyweight or the severity of metabolic acidosis. Patients who received early sodium bicarbonate had higher APACHE III scores, lower pH, lower base excess, lower PaCO2, and a higher lactate and received higher doses of vasopressors. After adjusting for confounders, the early administration of sodium bicarbonate was associated with an adjusted odds ratio (aOR) of 0.85 (95% CI, 0.44 to 1.62) for ICU mortality. In patients with vasopressor dependency, early sodium bicarbonate was associated with higher mean arterial pressure at 6 h and an aOR of 0.52 (95% CI, 0.22 to 1.19) for ICU mortality. CONCLUSIONS: Early metabolic acidosis is common in critically ill patients. Early sodium bicarbonate is administered by clinicians to more severely ill patients but without correction for weight or acidosis severity. Bicarbonate therapy in acidotic vasopressor-dependent patients may be beneficial and warrants further investigation.

Early Do-Not-Resuscitate Directives Decrease Invasive Procedures and Health Care Expenses During the Final Hospitalization of Life of COPD Patients.

CONTEXT: Nearly 70% of do-not-resuscitate (DNR) directives for chronic obstructive pulmonary disease (COPD) patients are established during their terminal hospitalization. Whether patient use of end-of-life resources differs between early and late establishment of a DNR is unknown. OBJECTIVES: The objective of this study was to compare end-of-life resource use between patients according to DNR directive status: no DNR, early DNR (EDNR) (established before terminal hospitalization), and late DNR (LDNR) (established during terminal hospitalization). METHODS: Electronic health records from all COPD decedents in a teaching hospital in Taiwan were analyzed retrospectively with respect to medical resource use during the last year of life and medical expenditures during the last hospitalization. Multivariate linear regression analysis was used to determine independent predictors of cost. RESULTS: Of the 361 COPD patients enrolled, 318 (88.1%) died with a DNR directive, 31.4% of which were EDNR. COPD decedents with EDNR were less likely to be admitted to intensive care units (12.0%, 55.5%, and 60.5% for EDNR, LDNR, and no DNR, respectively), had lower total medical expenditures, and were less likely to undergo invasive mechanical ventilator support during their terminal hospitalization. The average total medical cost during the last hospitalization was nearly twofold greater for LDNR than for EDNR decedents. Multivariate linear regression analysis revealed that nearly 60% of medical expenses incurred were significantly attributable to no EDNR, younger age, longer length of hospital stay, and more comorbidities. CONCLUSION: Although 88% of COPD decedents died with a DNR directive, 70% of these directives were established late. LDNR results in lower quality of care and greater intensive care resource use in end-of-life COPD patients.

Development of a Novel Shallow Liquid Interface Exposure System for MWCNT Toxicity Assessment.

Increasing applications of multiwalled carbon nanotubes (MWCNT) lead to significant occupational exposure and potential health concerns. Toxicity of MWCNT should be carefully elucidated since the conventional (CON) method with fully immersed condition fails to mimic the air-liquid interface (ALI) in airways. Additionally, quantification of MWCNT in cells was a real challenge. Currently available ALI exposure devices are costly, posing problems to conducting in vitro evaluations for emerging nanomaterials. A novel system, consisting of a shaker fluidized-bed atomizer (SFA) and electrostatic shallow liquid interface (ESLI) exposure chamber, has been developed for investigating nanotoxicity of well-dispersed pristine-MWCNT (pMWCNT) and carboxylized-MWCNT (cMWCNT). After 24-h exposure, LDH, MCP-1, IL-1ß, IL-6, and TNF-α releases were determined, and cell uptakes were quantified according to the molybdenum content in cells. Biological responses triggered by SLI exposure are obviously more sensitive compared with those caused by CON exposure at equivalent doses. Exposure dose-dependent release of LDH and IL-6 was highlighted in A549 cells, indicating higher cytotoxicity and inflammatory responses of cMWCNT attributed to its shorter length, smaller size, and higher cell uptake. Cell-associated dose-dependent release of LDH and IL-6 was highlighted in RAW264.7 cells, revealing the higher adverse health risk of pMWCNT due to frustrated phagocytosis and its much higher molybdenum content. These results suggest that inherent characteristics of cells and distinct physicochemical properties of pMWCNT and cMWCNT lead to either exposure dose-dependent or cell-associated dose-dependent responses. Notably, the SLI is superior to the CON exposure method and well suited for nanotoxicity assessment of different MWCNTs.