Delirium in a Medical Intensive Care Unit: A Report from a Tertiary Care University Hospital in Bangkok

Objective: Delirium is a common problem in critical care. Its prevalence in the unit varies, depending upon the severity of the illness and the diagnostic methods. Currently, the CAM-ICU is a diagnostic tool with good diagnostic accuracy. Our study aimed to determine the prevalence, associated factors, and outcomes of delirium in our unit by using the CAM-ICU.Methods: Our prospective cohort study included all patients admitted to the hospital’s medical ICU from August to December 2013. Patients with psychosis and/or in a coma (RAAS<-3) were excluded. We assessed delirium by using the CAM-ICU within the first 24 hours of admission and then serially, every 48 hours until discharge. Factors associated with this condition and patients’ outcomes were also explored.Results: A total of 74 patients were included. Of these, 43% were male, 40% had sepsis, and 81% were mechanically ventilated. Twenty-eight patients (38%) had delirium upon admission. The delirium patients were older and had a higher percentage of dementia. Univariate analysis revealed that dementia, anemia, acute metabolic acidosis, and the use of mechanical ventilation were associated with the occurrence of delirium, and, for age > 70 years, anemia and metabolic acidosis remained significant on multivariate analysis. Delirium was significantly associated with prolonged hospitalization (>30days), with OR = 4.84 (p=0.009), and with increased mortality, with OR = 25.0 (p=0.001).Conclusion: This study confirmed that delirium was common in the medical ICU and was associated with poor outcomes. Importantly, associated factors with delirium in our study appeared to be modifiable. Further study on early management and prevention of those risk factors is crucial.

Abnormalities in subsets of B and T cells in Mexican patients with inborn errors of propionate metabolism: observations from a single-center case series

Background: Propionate inborn errors of metabolism (PIEM), including propionic (PA) and methylmalonic (MMA) acidemias, are inherited metabolic diseases characterized by toxic accumulation of propionic, 3-hydroxypropionic, methylcitric, and methylmalonic organic acids in biological fluids, causing recurrent acute metabolic acidosis events and encephalopathy, which can lead to fatal outcomes if managed inadequately. PIEM patients can develop hematological abnormalities and immunodeficiency, either as part of the initial clinical presentation or as chronic complications. The origin and characteristics of these abnormalities have been studied poorly. Thus, the aim of the present work was to evaluate and describe lymphoid, myeloid, and erythroid cell population profiles in a group of clinically stable PIEM patients. Methods: This was a retrospective study of 11 nonrelated Mexican PIEM patients. Clinical, biochemical, nutritional, hematological, and lymphocyte subsets were analyzed. Results: Despite being considered clinically stable, 91% of patients had hematological or immunological abnormalities. The absolute lymphocyte subset counts were low in all patients but one, with CD4+ T-cell lymphopenia, being the most common one. Furthermore, of the 11 studied subjects, nine presented with a low CD4/CD8 ratio. Among the observed hematological alterations, bicytopenia was the most common (82%) one, followed by anemia (27%). Conclusion: Our results contribute to the landscape of immunological abnormalities observed previously in PIEM patients; these abnormalities can become a life-threatening chronic com-plications because of the increased risk of opportunistic diseases. These findings allow us to propose the inclusion of monitoring immune biomarkers, such as subsets of lymphocytes in the follow up of PIEM patients.

Etiology and Management of Acute Metabolic Acidosis: An Update

Background: The etiology of acute metabolic acidosis (aMA) is heterogeneous, and the consequences are potentially life-threatening. The aim of this article was to summarize the causes and management of aMA from a clinician’s perspective. Summary: We performed a systematic search on PubMed, applying the following search terms: “acute metabolic acidosis,” “lactic acidosis,” “metformin” AND “acidosis,” “unbalanced solutions” AND “acidosis,” “bicarbonate” AND “acidosis” AND “outcome,” “acute metabolic acidosis” AND “management,” and “acute metabolic acidosis” AND “renal replacement therapy (RRT)/dialysis.” The literature search did not consider diabetic ketoacidosis at all. Lactic acidosis evolves from various conditions, either with or without systemic hypoxia. The incidence of metformin-associated aMA is actually quite low. Unbalanced electrolyte preparations can induce hyperchloremic aMA. The latter potentially worsens kidney-related outcome parameters. Nevertheless, prospective and controlled data are missing at the moment. Recently, bicarbonate has been shown to improve clinically relevant endpoints in the critically ill, even if higher pH values (>7.3) are targeted. New therapeutics for aMA control are under development, since bicarbonate treatment can induce serious side effects. Key Messages: aMA is a frequent and potentially life-threatening complication of various conditions. Lactic acidosis might occur even in the absence of systemic hypoxia. The incidence of metformin-associated aMA is comparably low. Unbalanced electrolyte solutions induce hyperchloremic aMA, which most likely worsens the renal prognosis of critically ill patients. Bicarbonate, although potentially deleterious due to increased carbon dioxide production with subsequent intracellular acidosis, improves kidney-related endpoints in the critically ill.

Buffer Therapy in Acute Metabolic Acidosis: Effects on Acid-Base Status and Glomerular Permeability

ABSTRACTBackground:Correction of acute metabolic acidosis using sodium bicarbonate is effective, but has been hypothesized to exacerbate intra-cellular acidosis causing cellular dysfunction. The effects of acidemia and bicarbonate therapy on the cellular components of the glomerular filtration barrier, crucial for the integrity of the renal filter, are as yet unknown. Controversy persists regarding the most appropriate method to assess acid-base status: the “Stewart approach” or the “Siggaard-Andersen approach” using the standard base excess (SBE).Methods:Here we performed physiological studies in anesthetized Sprague-Dawley rats during severe metabolic acidosis (HCl iv 6 mmol kg-1) and following bicarbonate (2.5 mmol kg-1) administration. We assessed glomerular permeability using sieving coefficients of polydisperse fluorescein isothiocyanate (FITC)-Ficoll 70/400. Acid-base status was evaluated using SBE, standard bicarbonate, total CO2, the Stewart-Fencl strong ion difference (ΔSID = Na – Cl – 38) and a theoretical model of plasma and erythrocyte strong ion difference.Results:Our data show that neither acidosis nor its correction with NaHCO3altered glomerular permeability. We identified ΔSID as a strong estimator of plasma base excess (as assessed using the Van Slyke equation).In silicomodeling indicates that changes in the strong ion difference in erythrocytes would explain their buffering effect by means of a shift of anions from the extracellular fluid.Conclusion:These data demonstrate a remarkable tolerance of the glomerular filter to severe acute acidosis and bicarbonate therapy. Our results also cast light on the buffer mechanism in erythrocytes and the ability of different acid-base parameters to evaluate the extent of an acid-base disorder.IMPORTANCE STATEMENTMetabolic acidosis is a frequent complication of acute kidney injury in critically ill patients and is associated with a high risk of mortality. Correction of acidosis using sodium bicarbonate is simple and effective, but could possibly induce intracellular acidosis causing cellular dysfunction. The effects of acidemia and subsequent bicarbonate treatment on the cellular components of the glomerular filtration barrier, crucial for the integrity of the renal filter, are unknown. We show that neither severe acidemia nor bicarbonate therapy appear to have negative effects on glomerular permeability. Our analysis also highlights the buffering effects of erythrocytes, which appear to be mediated by a shift of strong anions into the red cells, increasing the strong ion difference in the extracellular fluid.

Prompt Rise in Urinary Ammonium Excretion Suffices To Mitigate Metabolic Acidosis in an Experimental Animal Model of Severe Normovolemic Hemodilution

Recently, we have established a model of severe stepwise normovolemic hemodilution to a hematocrit of 10 % in rats employing three different colloidal volume replacement solutions (Voluven, Volulyte and Gelafundin) that are routinely used in clinical practice at present. We did not see severe dilutional acidosis as to be expected, but a decline in urinary pH. We here looked on further mechanisms of renal acid excretion during normovolemic hemodilution. Bicarbonate, which had been removed during normovolemic hemodilution, was calculated with the help of the Henderson-Hasselbalch equation. The urinary amount of ammonium as well as phosphate was determined in residual probes. The absolute amount of free protons in urine was obtained from the pH of the respective samples. The amount of protons generated during normovolemic hemodilution was approximately 0.6 mmol. During experimental time (5.5 h), distinct urinary ammonium excretion occurred (Voluven 0.52 mmol, Volulyte 0.39 mmol and Gelafundin 0.77 mmol). Proton excretion via the phosphate buffer constituted 0.04 mmol in every experimental group. Excretion of free protons was in the range of 10-6 mmol. The present data prove that the prompt rise in urinary ammonium excretion is also valid for acute metabolic acidosis originating from severe normovolemic hemodilution.