Use of TIMP-2 and IGFBP-7 for prediction of postoperative acute kidney injury after cardiac surgery.

BACKGROUND: The following cell cycle arrest urinary biomarkers, tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP-7), have been used for early detection of acute kidney injury (AKI) in critically ill patients. The purpose of this study is to validate the use of these urinary biomarkers in patients undergoing open heart surgery. MATERIALS AND METHODS: In a single-center prospective observational study, urine samples were collected in 108 consecutive patients who underwent open heart surgery immediately after separation from cardiopulmonary bypass and on postoperative day 1, and were sent for the biomarker [TIMP-2]*[IGFBP7] analysis. Acute kidney injury was defined based on KDIGO criteria, and levels of [TIMP-2]*[IGFBP7] were analyzed for the ability to predict AKI. RESULTS: Of the 108 patients, 19 (17.6%) patients developed postoperative AKI within 48 hours of surgery. At the threshold of > 0.3 (ng/mL)2/1,000, post-cardiopulmonary bypass [TIMP-2]*[IGFBP-7] had a sensitivity of 13% and specificity of 82% for predicting postoperative AKI. Postoperative day-1 [TIMP-2]*[IGFBP-7] had a sensitivity of 47% and a specificity of 59% for predicting postoperative AKI. There were no differences in [TIMP-2]*[IGFBP-7] values at either timepoint between patients who developed postoperative AKI as compared to those who did not. CONCLUSION: Urinary [TIMP-2]*[IGFBP7] was not predictive of the risk of AKI after cardiac surgery in this single-center study population.

Our experience with two cardioplegic solutions: dextrose versus non-dextrose in adult cardiac surgery.

Intraoperative hyperglycemia has been observed to be associated with increased morbidity and mortality after cardiac surgery. Dextrose cardioplegia is used for its cardioprotective effects but may lead to intraoperative hyperglycemia and more postoperative complications. This was a retrospective observational study. Patient records (n = 2301) were accessed from a large database at a tertiary care facility. The two groups (dextrose vs. nondextrose) were then matched using preoperative variables of age, sex, body mass index, wound exposure time, preoperative HbA1c levels, renal failure, hypertension, and prior cerebrovascular disease. The following outcomes were recorded: 30-day mortality, sternal wound infection, stroke, and highest glucose level on cardiopulmonary bypass. The dextrose cardioplegia group showed statistically higher intraoperative glucose levels (272.76 +/- 55.92 vs. 182.79 +/- 45, p value = .0001). There was no difference in postoperative mortality, sternal wound infections or stroke incidence, nor in other secondary outcomes. The type of cardioplegia solution was shown to affect glucose levels; however, there was no effect on postoperative complication rates.

Assessment of cardiac recovery in patients supported with venoarterial extracorporeal membrane oxygenation.

AIMS: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly being used to support patients in cardiogenic shock (CS). Early determination of disposition is paramount, as longer durations of support have been associated with worse outcomes. We describe a stepwise, bedside weaning protocol to assess cardiopulmonary recovery during VA-ECMO. METHODS AND RESULTS: Over 1 year, we considered all patients on VA-ECMO for CS for the Weaning Protocol (WP) at our centre. During the WP, patients had invasive haemodynamic monitoring, echocardiography, and blood gas analysis while flow was reduced in 1 LPM decrements. Ultimately, the circuit was clamped for 30 min, and final measures were taken. Patients were described as having durable recovery (DR) if they were free of pharmacological and mechanical support at 30 days post-decannulation. Over 12 months, 34 patients had VA-ECMO for CS. Fourteen patients were eligible for the WP at 4-12 days. Ten patients tolerated full flow reduction and were successfully decannulated. Twenty-four per cent of the entire cohort demonstrated DR with no adverse events during the WP. Patients with DR had significantly higher ejection fraction, cardiac index, and smaller left ventricular size at lowest flow during the WP. CONCLUSIONS: We describe a safe, stepwise, bedside weaning protocol to assess cardiac recovery during VA-ECMO. Early identification of patients more likely to recover may improve outcomes during ECMO support.

Hypermetabolism in critically ill patients with COVID-19 and the effects of hypothermia: A case series.

BACKGROUND: We have observed that critically ill patients with COVID-19 are in an extreme hypermetabolic state. This may be a major contributing factor to the extraordinary ventilatory and oxygenation demands seen in these patients. We aimed to quantify the extent of the hypermetabolic state and report the clinical effect of the use of hypothermia to decrease the metabolic demand in these patients. METHODS: Mild hypothermia was applied on four critically ill patients with COVID-19 for 48 h. Metabolic rates, carbon dioxide production and oxygen consumption were measured by indirect calorimetry. RESULTS: The average resting energy expenditure (REE) was 299% of predicted. Mild hypothermia decreased the REE on average of 27.0% with resultant declines in CO2 production (VCO2) and oxygen consumption (VO2) by 29.2% and 25.7%, respectively. This decrease in VCO2 and VO2 was clinically manifested as improvements in hypercapnia (average of 19.1% decrease in pCO2 levels) and oxygenation (average of 50.4% increase in pO2). CONCLUSION: Our case series demonstrates the extent of hypermetabolism in COVID-19 critical illness and suggests that mild hypothermia reduces the metabolic rate, improves hypercapnia and hypoxia in critically ill patients with COVID-19.

Hypermetabolism and Coronavirus Disease 2019.

BACKGROUND: Hypermetabolism has been described in stress states such as trauma, sepsis, acute respiratory distress syndrome, and severe burn injuries. We hypothesize that patients with Coronavirus disease 2019 (COVID-19) may develop a hypermetabolic state, which may be a major contributing factor to the extraordinary ventilatory and oxygenation demands in patients with COVID-19. METHOD: Resting energy expenditure (REE), carbon dioxide production (VCO2 ), and oxygen consumption (VO2 ) were measured by indirect calorimetry on 7 critically ill patients with COVID-19. RESULTS: The median measured REE was 4044 kcal/d, which was 235.7% ± 51.7% of predicted. The median VCO2 was 452 mL/min (range, 295-582 mL/min), and the median VO2 was 585 mL/min (range, 416-798 mL/min). CONCLUSION: Critically ill patients with COVID-19 are in an extreme hypermetabolic state. This may explain the high failure rates for mechanical ventilation for these patients and highlights the potential need for increased nutrition requirements for such patients.

Exchange transfusion before cardiopulmonary bypass in sickle cell disease.

Cardiac operations in patients with sickle cell disease present the surgical team with many challenges. We describe a method of complete intraoperative exchange transfusion in the operating room that reduces the hemoglobin S (Hb S) level to less than 5%, without preoperative exchange transfusions. Plasma and platelet fractions separated intraoperatively from the patient's native red cell mass were used, in addition to hemoconcentration while on cardiopulmonary bypass, to effectively reduce the red cell and clotting factor transfusion requirements after the procedure. The technique is useful in reducing transfusion requirements, avoiding cardiovascular stress associated with exchange transfusion before the operation, and can be used in urgent situations.