Endogenous Purulent Pericarditis Due to Klebsiella aerogenes in a Patient With Traumatic Chest Injury: A Case Report

Purulent pericarditis is a rare but serious medical condition caused by an infection that spreads to the pericardial space surrounding the heart. Gram-positive organisms are the most common pathogens associated with purulent pericarditis. However, there has been a shift in recent years toward gram-negative bacteria. Klebsiella aerogenes is a rare pathogen that has never been linked to purulent pericarditis. In this report, we describe the case of a 40-year-old male patient with chronic bronchiectasis who, two months after suffering an injury, developed purulent pericarditis due to an uncommon organism, K. aerogenes. During his stay in the hospital, the patient developed several infections caused by K. aerogenes. These included bacteremia and ventilator-associated pneumonia (VAP). Beta-lactamase-inducible K. aerogenes was grown in pericardial fluid culture following an emergency pericardiocentesis. The organism was resistant to carbapenems in a sputum culture, even though it was sensitive to meropenem in a blood culture. The patient had hypotension, requiring inotropes, and continued persistent bacteremia due to K. aerogenes. The patient had a heart attack with no pulse or electrical activity and died despite getting the best care possible. In light of this example, it is crucial to think about K. aerogenes and other rare organisms as possible pathogens in purulent pericarditis, especially in people who do not normally have known risk factors for this condition. Multidrug resistance patterns can make treatment more complicated, and aggressive care may be necessary in critically ill patients with chronic bacteremia.

Implementation of new ECMO centers during the COVID-19 pandemic: experience and results from the Middle East and India

Purpose

Extracorporeal membrane oxygenation (ECMO) use for severe coronavirus disease 2019 (COVID-19) patients has increased during the course of the pandemic. As uncertainty existed regarding patient’s outcomes, early guidelines recommended against establishing new ECMO centers. We aimed to explore the epidemiology and outcomes of ECMO for COVID-19 related cardiopulmonary failure in five countries in the Middle East and India and to evaluate the results of ECMO in 5 new centers.

Methods

This is a retrospective, multicenter international, observational study conducted in 19 ECMO centers in five countries in the Middle East and India from March 1, 2020, to September 30, 2020. We included patients with COVID-19 who received ECMO for refractory hypoxemia and severe respiratory acidosis with or without circulatory failure. Data collection included demographic data, ECMO-related specific data, pre-ECMO patient condition, 24 h post-ECMO initiation data, and outcome. The primary outcome was survival to home discharge. Secondary outcomes included mortality during ECMO, survival to decannulation, and outcomes stratified by center type.

Results

Three hundred and seven COVID-19 patients received ECMO support during the study period, of whom 78 (25%) were treated in the new ECMO centers. The median age was 45 years (interquartile range IQR 37–52), and 81% were men. New center patients were younger, were less frequently male, had received higher PEEP, more frequently inotropes and prone positioning before ECMO and were less frequently retrieved from a peripheral center on ECMO. Survival to home discharge was 45%. In patients treated in new and established centers, survival was 55 and 41% (p = 0.03), respectively. Multivariable analysis retained only a SOFA score < 12 at ECMO initiation as associated with survival (odds ratio, OR 1.93 (95% CI 1.05–3.58), p = 0.034), but not treatment in a new center (OR 1.65 (95% CI 0.75–3.67)).

Conclusions

During pandemics, ECMO may provide favorable outcomes in highly selected patients as resources allow. Newly formed ECMO centers with appropriate supervision of regional experts may have satisfactory results.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00134-021-06451-w.

ICU Telemedicine Implementation and Risk-Adjusted Mortality Differences Between Daytime and Nighttime Coverage

BACKGROUND

ICU telemedicine augmentation has been associated with improvements in clinical and financial outcomes in many cases, but not all. Understanding this discrepancy is of interest given the clinical impact and intervention cost. A recent meta-analysis noted an association with mortality reduction and standardized mortality ratio (SMR) before ICU telemedicine implementation of > 1.

RESEARCH QUESTION

Does ICU telemedicine implementation affect adjusted mortality outcomes? If so, in what context?

STUDY DESIGN AND METHODS

We performed a retrospective pre-post analysis comparing before vs after ICU telemedicine implementation on the outcome of risk-adjusted ICU mortality during am vs pm admissions as well as other objective measures of ICU telemedicine involvement.

RESULTS

One thousand five hundred eighty-one patient-stays and 14,584 patient-stays were available for analysis in the implementation period before vs after ICU telemedicine implementation, respectively. The average Acute Physiology and Chronic Health Evaluation (APACHE) IVa score was 46.6 vs 54.8 (P < .01) in the am group before ICU telemedicine implementation vs the am group after ICU telemedicine implementation, respectively. The average APACHE IVa score was 47.2 vs 56.3 (P < .01) in the pm group before ICU telemedicine implementation vs the pm group after ICU telemedicine implementation, respectively. Overall, the risk-adjusted ICU mortality was 8.7% before ICU telemedicine implementation vs 6.5% (P < .01) after implementation. When stratified by am and pm admission groups, no significant difference in risk-adjusted ICU mortality was seen in the am stratum. In the pm stratum, risk-adjusted mortality was 10.8% before ICU telemedicine implementation vs 7.0% (P < .01) after ICU telemedicine implementation. The preimplementation SMR in the am admission stratum was 0.95 vs 1.30 in the pm stratum.

INTERPRETATION

We found a reduction in risk-adjusted ICU mortality with implementation of ICU telemedicine driven predominantly within the pm admission group. The pm admission SMR was 1.30, which may suggest an association with SMR of > 1 before ICU telemedicine implementation and mortality reduction. Future studies should seek to confirm this finding and should explore other important ICU telemedicine outcomes in the context of observed-to-expected ratios.

Hyperglycemia in Medically Critically Ill Patients: Risk Factors and Clinical Outcomes

BACKGROUND

We aimed to robustly categorize glycemic control in our medical intensive care unit (ICU) as either acceptable or suboptimal based on time-weighted daily blood glucose averages of <180 mg/dL or >180 mg/dL; identify clinical risk factors for suboptimal control; and compare clinical outcomes between the 2 glycemic control categories.

METHODS

This was a retrospective cohort study in an academic tertiary and quaternary medical ICU.

RESULTS

Out of total of 974 unit stays over a 2-year period, 920 had complete data sets available for analysis. Of unit stays 63% (575) were classified as having acceptable glycemic control and the remaining 37% were classified (345) as having suboptimal glycemic control. Adjusting for covariables, the odds of suboptimal glycemic control were highest for patients with diabetes mellitus (odds ratio [OR] 5.08, 95% confidence interval [CI] 3.72-6.93), corticosteroid use during the ICU stay (OR 4.50, 95% CI 3.21-6.32), and catecholamine infusions (OR 1.42, 95% CI 1.04-1.93). Adjusting for acuity, acceptable glycemic control was associated with decreased odds of hospital mortality but not ICU mortality (OR 0.65, 95% CI 0.48-0.88 and OR 0.81, 95% CI 0.55-1.17, respectively). Suboptimal glycemic control was associated with increased odds of longer-than-predicted ICU and hospital stays (OR 1.76, 95% CI 1.30-2.38 and OR 1.50, 95% CI 1.12-2.01, respectively).

CONCLUSIONS

In our high-acuity medically critically ill patient population, achieving time-weighted average daily blood glucose levels <180 mg/dL reliably while in the ICU significantly decreased the odds of subsequent hospital mortality. Suboptimal glycemic control during the ICU stay, on the other hand, significantly increased the odds of longer-than-predicted ICU and hospital stay.

An improved animal model for studying desferrioxamine

A hamster model has been developed for studying desferrioxamine. The hamster shows many similarities to man in terms of plasma stability and metabolites formed from desferrioxamine. The [59Fe]ferritin derived from rats has been shown to be sequestered into liver parenchymal cells when injected intravenously into hamsters. The technique has proved sufficiently sensitive to enable detection of differences of < 1% of the radioactivity administered in the elimination of iron. Alterations in iron excretion were seen when dosing desferrioxamine via different routes. The principal route of iron excretion was into the intestines. The effectiveness of the dosing routes for desferrioxamine in removing iron were subcutaneous (10.5%) > intravenous (6.25%) > oral (3.66%) > control (2.19%). A dose-response relationship was demonstrated using the intravenous dose route. The model offers a simple method for comparing the efficacy of administration routes for determining the optimal use of desferrioxamine.

The transport of acidic amino acids and their analogues across monolayers of human intestinal absorptive (Caco-2) cells in vitro

The X-AG system, a sodium-dependent, acidic amino-acid transport system has been implicated in the transport of L-aspartate and L-glutamate across monolayers of human Caco-2 cells, an in vitro model of intestinal absorption. This system, which shares many properties with the L-glutamate carrier present in the human jejunum, is highly saturable (> 95% at 50 microM), vectorial (apical-to-basolateral >> basolateral-to-apical) and sodium-, pH- and temperature-dependent. L-Aspartate was also transported against a 10-fold reverse concentration gradient. These data are consistent with a major (saturable) carrier-mediated pathway superimposed onto a minor non-saturable (diffusional) pathway. The carrier has an absolute sodium-dependence and the Michaelis constants for the sodium-dependent transport component (Km) for L-aspartate and L-glutamate were 56 +/- 3 microM and 65 +/- 6 microM, respectively. Cross-inhibition studies showed that strong interaction with the carrier was limited to close analogues of the natural substrates. Potent inhibitors included L-aspartate, D-aspartate (Ki, 70 microM), L-glutamate (Ki 180 microM) and threo-beta-hydroxy-DL-aspartate (Ki, 55 microM), while partial inhibitors included alpha-methyl-DL-aspartate, D-glutamate, L-asparagine, L-proline and L-alanine. Replacement of the side-chain -COO- group (aspartate) with -SO-3 (L-cysteate, Ki, 65 microM) or -(H)P(O)O- (DL-3-(hydroxyphosphoryl)alanine, Ki, 60 microM) maintained strong interaction with the carrier while -As(O)(OH)O- (DL-3-arsonoalanine, Ki, 1100 microM) and -P(O)(OH)O- (DL-3-phosphonoalanine, Ki, 3270 microM) were much more weakly bound, with the larger, but probably less ionised, arsono analogue being more tightly bound than the phosphono compound. The corresponding analogues of glutamate (homologous extension of the methylene chain) showed negligible interaction. We conclude that Caco-2 monolayers are a relevant experimental model for the study of the transport of acidic amino acids and their analogues in man.

Proline uptake by monolayers of human intestinal absorptive (Caco-2) cells in vitro

Monolayers of the Caco-2 human intestinal cell line exhibit active and passive uptake systems for the imino acid L-proline. The active transport component is saturable and it is responsible for about two thirds of the observed flux over the nanomolar concentration range, at 37 degrees C and pH 7.4. In contrast to L-phenylalanine, specific L-proline uptake has a high degree of sodium dependency and the efficiency of the carrier system is significantly reduced when protein synthesis (cycloheximide), Na+/K(+)-ATPase (ouabain) or cellular metabolism (sodium azide) are inhibited. The expression of the L-proline carrier by Caco-2 cells was under some degree of nutritional control. Glucose deficiency, over the time scale of the experiment, had no effect. The temperature-dependence of the specific uptake process followed the Arrhenius model with an apparent activation energy of 93.5 kJ nmol-1. This pathway also displayed Michaelis-Menten concentration-dependence with a Ksdm of 5.28 mM and a maximal transport flux (Jsdmax) of 835 pmol min-1 (10(6) cells)-1. Although the passive component was unchanged, the pH of the donor phase exerted a profound effect on the active carrier component. Within the physiological pH range a local maximum efficiency was found at pH 7.4 but dramatic increases were noted as pH 5.0 was approached. In competition studies, with 100-fold excess of a second amino acid, strong inhibition of uptake was found with alpha-aminoisobutyric acid, L-alanine and L-serine whereas moderate inhibition was observed with glycine, D-proline and gamma-aminoisobutyric acid. Aromatic and branched amino acids showed weak (L-valine) or no interaction (L-phenylalanine, L-leucine) with the carrier system. These data indicate that the carrier system for the uptake of L-proline has many features in common with the A system for amino acid transport.

The transport of vitamin B12 through polarized monolayers of Caco-2 cells

Caco-2 cells grown on 0.45-micron filters, in Millicell chambers, form intact monolayers with many of the properties of polarized intestinal epithelial cells. It is reported here that these cells bind and internalize intrinsic factor-cobalamin complexes and that after 14-28 days in culture this specific binding is exclusively located on the apical membrane. Caco-2 cells also synthesize and secrete a protein with properties similar to transcobalamin II. This protein is secreted from the basolateral side of the cells after 20 days in culture. Specific apical-to-basolateral transcellular transport of [57Co]cobalamin also occurs between 20 and 28 days in culture. Thus, Caco-2 cells provide the first polarized human cell system for studying the transepithelial transport of cobalamin.

On the fidelity of the lactoperoxidase method of cell membrane radioiodination: an electron microscopic autoradiographic study

The radiolabelling of human peripheral blood lymphocytes by lactoperoxidase-catalysed iodination using 2 different sources of hydrogen peroxide has been compared using electron microscopic autoradiography. A method of statistical analysis of the autoradiographs has permitted precise identification of radioactive sources, in particular cellular compartments, taking into account cross-fire of Auger electrons producing silver grains in compartments other than those from which they are emitted. Our data confirm the postulates of previous investigators that the majority of radioiodine is located at the plasma membrane of cells labelled by enzymic iodination. The results further suggest that the glucose-glucose oxidase system for generation of hydrogen peroxide permits a greater degree of specific radiolabelling of plasma membrane proteins with less damage than equivalent lactoperoxidase iodination reactions promoted by exogenously added hydrogen peroxide.