Epidemiology and outcomes of infections during extracorporeal membrane oxygenation in adult patients with COVID-19 ARDS- A single center study.

BACKGROUND: There is a scarcity of data regarding nosocomial infections in patients with COVID-19 treated with ECMO. This observational study from India aims to describe the epidemiology and microbiology of infections in patients with COVID-19 associated ECMO. METHODS: This is an ambi-directional observational study of COVID-19 ECMO patients admitted from April 2021 to June 2022 in a tertiary care hospital. The total number of sepsis episodes for each patient was recorded and were categorized as bloodstream infections (BSI), pneumonias, skin and soft tissue infections (SSTI), invasive candidiasis (IC), catheter associated urinary tract infection (CAUTI), intra-abdominal infections (IAI), and Clostridioides difficile infections. Details regarding each infection including the microbiological profile and outcomes were recorded. RESULTS: 29 patients who received ECMO for COVID-19 pneumonia during the study period were identified. Of the 29 patients, there were a total of 185 septic episodes. The incidence of septic episodes was 72.4 per 1000 ECMO days. Of the 185 sepsis events, 82 (44.3%) were BSI, 72 (39%) were pneumonia, 19 (10.3%) were SSTI, 7 (3.8%) were CAUTI and 5 (2.7%) were IAIs. Of these 29 patients, 16 (55.2%) patients were discharged and 13 (44.8%) died. CONCLUSIONS: The most common infections in our patients were bloodstream infections followed by pneumonia. High rates of gram negative infections, including those caused by carbapenem resistant bacteria, reflect the Indian critical care unit epidemiology in general. Despite these high infection rates with antimicrobial resistant set of micro-organisms, we had a successful outcome in 55.2% of patients.

A dual mode 'turn-on' fluorescence-Raman (SERS) response probe based on a 1H-pyrrol-3(2H)-one scaffold for monitoring H2S levels in biological samples.

Discovery of the biological signaling roles of H2S has spurred great interest in developing reliable methods for its accurate detection and quantification. As considerable variation in its levels is seen during pathological conditions such as sepsis, real-time quantification methods have relevance in diagnosis as well. Of various approaches, reaction-based probes which respond through 'off-on' fluorescence emission remain the most studied. Since the intensity of emission is related to the analyte concentration in these measurements, the presence of built-in features which provide an opportunity for internal referencing will be advantageous. In view of this, a dual mode response system that senses H2S through characteristic fluorescence and Raman (SERS) signals based on a 1H-pyrrol-3(2H)-one scaffold was developed and is the main highlight of this report. This probe offers several advantages such as fast response (<1 min), and high selectivity and sensitivity with a detection limit of ∼7 nM. Imaging of H2S in HepG2 cells, making use of the SERS signal from the thiolysis product is also demonstrated.

Caecal bascule following lung transplantation.

Caecal bascule refers to a rare condition wherein the caecum folds upon the ascending colon causing intestinal obstruction. We describe a case report of caecal bascule following lung transplantation which required right hemicolectomy. It was initially thought to be due to post-operative paralytic ileus which is, not uncommonly, seen following lung transplantation. While most cases of paralytic ileus respond to conservative measures, it is important to maintain a close watch-keeping in mind a high degree of suspicion for possible surgically correctable causes, which can be a lifesaving intervention. The clinical dilemma in subjecting a heavily immunosuppressed patient, soon after lung transplantation (where painless abdominal distention is not uncommon), to a major abdominal surgery in the background of minimal clinical signs of acute abdomen is discussed. The thought process behind the surgical strategy, including the pros and cons of various surgical options and the management of nutrition and immunosuppression in this patient, is elaborated.

The physiological basis of clinical decision-making in venoarterial extracorporeal life support.

Venoarterial (VA) extracorporeal life support (ECLS) or extracorporeal membrane oxygenation (ECMO) as it is commonly known is used in many clinical situations to support both the pumping action of the heart and the gas exchange function of the lungs. This review hopes to refresh, in the mind of the reader, aspects of basic physiological principles that have relevance in VA ECLS therapy. The dynamics of the interaction of the machine with the patient and vice versa plays an important role in clinical outcome. An understanding of the variation from normal physiology imposed both by the machine and the disease process will help make enlightened decisions in the use of this challenging therapy. The key physiological changes during initiation, maintenance, and weaning are discussed as well as certain specific clinical scenarios.

Altered kinetics of circulating progenitor cells in cardiopulmonary bypass (CPB) associated vasoplegic patients: A pilot study.

Vasoplegia observed post cardiopulmonary bypass (CPB) is associated with substantial morbidity, multiple organ failure and mortality. Circulating counts of hematopoietic stem cells (HSCs) and endothelial progenitor cells (EPC) are potential markers of neo-vascularization and vascular repair. However, the significance of changes in the circulating levels of these progenitors in perioperative CPB, and their association with post-CPB vasoplegia, are currently unexplored. We enumerated HSC and EPC counts, via flow cytometry, at different time-points during CPB in 19 individuals who underwent elective cardiac surgery. These 19 individuals were categorized into two groups based on severity of post-operative vasoplegia, a clinically insignificant vasoplegic Group 1 (G1) and a clinically significant vasoplegic Group 2 (G2). Differential changes in progenitor cell counts during different stages of surgery were compared across these two groups. Machine-learning classifiers (logistic regression and gradient boosting) were employed to determine if differential changes in progenitor counts could aid the classification of individuals into these groups. Enumerating progenitor cells revealed an early and significant increase in the circulating counts of CD34+ and CD34+CD133+ hematopoietic stem cells (HSC) in G1 individuals, while these counts were attenuated in G2 individuals. Additionally, EPCs (CD34+VEGFR2+) were lower in G2 individuals compared to G1. Gradient boosting outperformed logistic regression in assessing the vasoplegia grouping based on the fold change in circulating CD 34+ levels. Our findings indicate that a lack of early response of CD34+ cells and CD34+CD133+ HSCs might serve as an early marker for development of clinically significant vasoplegia after CPB.

Transcatheter aortic valve replacement in India-Early experience, challenges, and outcomes from a single center.

BACKGROUND: Despite the increasing popularity of transcatheter aortic valve replacement (TAVR), only about 10,000 TAVR cases have been performed in Asia to date. The procedure is still in a nascent stage in India with very few centers offering this state-of-art technique. Here, we present the early results of TAVR experience at our center. METHODS: Forty-nine patients with severe symptomatic aortic stenosis (AS) were referred to our center for TAVR from November 2015 to February 2018. Twenty-five patients underwent TAVR at our conventional cardiac catheterization laboratory under local or general anesthesia, with standby surgical team support. RESULTS: The mean age of the patients was 72.0 ± 8.1 years. The mean Society of Thoracic Surgeons score was 13.8 ± 10.2. Baseline mean ejection fraction was 50.3 ± 14.8%. Baseline mean aortic valve gradient was 55.8 ± 24.7 mmHg. There was one procedural-related death. Two of the patients required urgent surgery: one for contained annular rupture and one underwent vascular repair for femoral artery occlusion. Mild and moderate paravalvular leak was seen in 11 and 3 patients, respectively. Four patients (16%) required permanent pacemaker. Eighty percent were in New York Heart Association class I-II at discharge. One-year all-cause mortality was 8%, with no hospitalizations or major adverse cardiac event during the 1-year follow-up. CONCLUSION: Our early data clearly shows that in our country, TAVR is a good alternative for symptomatic severe AS for high surgical risk cases. Large-scale multicenter studies are required to study the real impact of TAVR in the Indian scenario. During initial years of implementation of a nationwide TAVR program, it may be prudent to focus on creating TAVR Centers of Excellence by developing an ideal hub and spokes model.

Analysis and modelling of septic shock microarray data using Singular Value Decomposition.

Being a high throughput technique, enormous amounts of microarray data has been generated and there arises a need for more efficient techniques of analysis, in terms of speed and accuracy. Finding the differentially expressed genes based on just fold change and p-value might not extract all the vital biological signals that occur at a lower gene expression level. Besides this, numerous mathematical models have been generated to predict the clinical outcome from microarray data, while very few, if not none, aim at predicting the vital genes that are important in a disease progression. Such models help a basic researcher narrow down and concentrate on a promising set of genes which leads to the discovery of gene-based therapies. In this article, as a first objective, we have used the lesser known and used Singular Value Decomposition (SVD) technique to build a microarray data analysis tool that works with gene expression patterns and intrinsic structure of the data in an unsupervised manner. We have re-analysed a microarray data over the clinical course of Septic shock from Cazalis et al. (2014) and have shown that our proposed analysis provides additional information compared to the conventional method. As a second objective, we developed a novel mathematical model that predicts a set of vital genes in the disease progression that works by generating samples in the continuum between health and disease, using a simple normal-distribution-based random number generator. We also verify that most of the predicted genes are indeed related to septic shock.

Quantification of photocatalytic oxygenation of human blood.

Photocatalytic oxygenation of human blood is an emerging concept based on the principle of photocatalytic splitting of water into oxygen and hydrogen. This communication reports: (i) a design of a photocatalytic cell (PC) that separates the blood from UV (incident) radiation source, (ii) a pH, temperature and flow controlled circuit designed for quantifying the oxygenation of human blood by photocatalysis and (iii) measuring the current efficacy of ITO/TiO2 nano thin films in oxygenating human blood in a dynamic circuit in real time. The average increase in oxygen saturation was around 5% above baseline compared to control (p<0.0005). We believe this is one of the first attempts to quantify photocatalytic oxygenation of human blood under controlled conditions.