Development of a cost-effective ex vivo lung perfusion system for lung transplantation in India.

Background & objectives: Standard donor lung preservation with cold flush and storage allows up to six hours between retrieval of lungs from the donor and transplantation in the recipient. Ex vivo lung perfusion (EVLP) systems mimic physiological ventilation and perfusion in the donor lungs with potential for prolonged lung preservation and donor lung reconditioning. In this study, it was aimed to perform EVLP on discarded donor lungs using a locally developed EVLP system. Methods: Equipment that are routinely used for cardiac surgeries were collected and a functional EVLP system was assembled. This system was used on five pairs of lungs retrieved from brain-dead organ donors. The lungs were ventilated and pulmonary circulation was continuously perfused with a solution containing oxygen and nutrients for four hours. The system was tested without red blood cells (RBCs) added to the solution (acellular group; n=3; A1, A2 and A3) and also with RBCs added to the solution (cellular group; n=2; C1 and C2). Results: The EVLP system was successfully used in four (A1, A2, A3 and C2) of the five lung pairs. Mechanical and gas exchange functions of the lungs were preserved in these lung pairs. One lung pair (C1) worsened and developed pulmonary oedema. Histopathological examination of all five lung pairs was satisfactory at the end of the procedure. Major challenges faced were leakage of solution from the system and obstruction to drainage of RBCs containing solution from the lungs. Interpretation & conclusions: The results of the present study suggest that, it is possible to maintain the lungs retrieved for transplantation in a physiological condition using a locally prepared EVLP system and a solution without RBCs.

Intraoperative evaluation of renal resistive index with transesophageal echocardiography for the assessment of acute renal injury in patients undergoing coronary artery bypass grafting surgery: A prospective observational study.

Background: Acute kidney injury (AKI) is a common complication after on pump coronary artery bypass grafting (CABG) surgery and is associated with a poor prognosis. Postoperative AKI is associated with morbidity, mortality, and increase in length of intensive care unit (ICU) stay and increases the financial burden. Identifying individuals at risk for developing AKI in postoperative period is extremely important to optimize outcomes. The aim of the study is to evaluate the association between the intraoperative transesophageal echocardiography (TEE) derived renal resistive index (RRI) and AKI in patients undergoing on-pump CABG surgery. Methods: This prospective observational study was conducted in patients more than 18 years of age undergoing elective on pump CABG surgery between July 1, 2018, and December 31, 2019, at a tertiary care center. All preoperative, intraoperative, and postoperative parameters were recorded. TEE measurement was performed in hemodynamically stable patients before the sternum was opened. Postoperative AKI was diagnosed based on the serial measurement of serum creatinine and the monitoring of urine output. Results: A total of 115 patients were included in our study. Thirty-nine (33.91%) patients had RRI >0.7 while remaining seventy-six (66.08%) patients had RRI <0.7. AKI was diagnosed in 26% (30/115) patients. AKI rates were significantly higher in patients with RRI values exceeding 0.7 with 46.15% (18/39) compared to 15.75% (12/76) in RRI values of less than 0.7. Multivariate analysis revealed that AKI was associated with an increase in RRI and diabetes mellitus. The RRI assessed by receiver operating characteristic (ROC) curve and the area under the curve (AUC) to distinguish between non-AKI and AKI groups were 0.705 (95% CI: 0.588-0.826) for preoperative RRI. The most accurate cut-off value to distinguish non-AKI and AKI groups was a preoperative RRI of 0.68 with a sensitivity of 70% and specificity of 67%. Conclusions: An increased intraoperative RRI is an independent predictor of AKI in the postoperative period in patients undergoing CABG surgery. The cutoff value of TEE-derived RRI in the intraoperative period should be >0.68 to predict AKI in the postoperative period.

Quantitative Assessment of Nitrous Oxide Levels in Room Air of Operation Theaters and Recovery Area: An Observational Study.

BACKGROUND: Nitrous oxide has been used during surgical anesthesia for many years. However, information about occupational exposure and related risks due to N2O exposure to the health care personnel in India are still poorly understood. Here, we measured the residual N2O levels during the working time of operation theatre room air in our tertiary care hospital. MATERIAL AND METHODS: The air samples were collected from different anesthesia exposure zones on different days for quantitative analysis of available N2O in the room air in respective areas. Nitrous oxide concentrations in the ambient air were also measured to compare outdoor and indoor levels. OBSERVATIONS AND RESULTS: Nitrous oxide mixing ratios were found to be 65.61 ± 0.05 ppm, 281.63 ± 0.43 ppm, and 165.42 ± 0.42 ppm in elective surgical theatres of the hospital on three different days whereas in emergency operation theatres of the same hospital levels of N2O were 166.75 ± 0.07 ppm, 510.19 ± 0.30 ppm and 2443.92 ± 0.64 ppm during same period. In elective pediatric surgical theatres levels of N2O were found to be 1132.55 ± 0.70 ppm and 362.21 ± 0.13 ppm on two days of reading respectively. Outdoor levels of N2O in contrast found 0.32 ± 0.01 ppm and was lower by a factor of 1000. CONCLUSION: We observed the very high ambient concentration of N2O in the surgical theatre's environment (up to 2443 ppm) and recovery areas (up to 50 ppm). It was 5 to 50 times higher ambient concentration of N2O than REL in OT area and 200-7000 times higher ambient concentration of N2O than outdoor ambient air in all surgical theaters other than CTVS OTs.

Point-of-Care Echocardiography and Hemodynamic Monitoring in Cirrhosis and Acute-on-Chronic Liver Failure in the COVID-19 Era.

Point-of-Care (POC) transthoracic echocardiography (TTE) is transforming the management of patients with cirrhosis presenting with septic shock, acute kidney injury, hepatorenal syndrome and acute-on-chronic liver failure (ACLF) by correctly assessing the hemodynamic and volume status at the bedside using combined echocardiography and POC ultrasound (POCUS). When POC TTE is performed by the hepatologist or intensivist in the intensive care unit (ICU), and interpreted remotely by a cardiologist, it can rule out cardiovascular conditions that may be contributing to undifferentiated shock, such as diastolic dysfunction, myocardial infarction, myocarditis, regional wall motion abnormalities and pulmonary embolism. The COVID-19 pandemic has led to a delay in seeking medical treatment, reduced invasive interventions and deferment in referrals leading to "collateral damage" in critically ill patients with liver disease. Thus, the use of telemedicine in the ICU (Tele-ICU) has integrated cardiology, intensive care, and hepatology practices across the spectrum of ICU, operating room, and transplant healthcare. Telecardiology tools have improved bedside diagnosis when introduced as part of COVID-19 care by remote supervision and interpretation of POCUS and echocardiographic data. In this review, we present the contemporary approach of using POC echocardiography and offer a practical guide for primary care hepatologists and gastroenterologists for cardiac assessment in critically ill patients with cirrhosis and ACLF. Evidenced based use of Tele-ICU can prevent delay in cardiac diagnosis, optimize safe use of expert resources and ensure timely care in the setting of critically ill cirrhosis, ACLF and liver transplantation in the COVID-19 era.