High-flow nasal cannula for Acute Respiratory Distress Syndrome (ARDS) due to COVID-19.

INTRODUCTION: High-flow nasal cannula oxygen therapy (HFNC) has been shown to be a useful therapy in the treatment of patients with Acute Respiratory Distress Syndrome (ARDS), but its efficacy is still unknown in patients with COVID-19. Our objective is to describe its utility as therapy for the treatment of ARDS caused by SARS-CoV-2. METHODS: A retrospective, observational study was performed at a single centre, evaluating patients with ARDS secondary to COVID-19 treated with HFNC. The main outcome was the intubation rate at day 30, which defined failure of therapy. We also analysed the role of the ROX index to predict the need for intubation. RESULTS: In the study period, 196 patients with bilateral pneumonia were admitted to our pulmonology unit, 40 of whom were treated with HFNC due to the presence of ARDS. The intubation rate at day 30 was 52.5%, and overall mortality was 22.5%. After initiating HFNC, the SpO2/FiO2 ratio was significantly better in the group that did not require intubation (113.4±6.6 vs 93.7±6.7, p=0.020), as was the ROX index (5.0±1.6 vs 4.0±1.0, p=0.018). A ROX index less than 4.94 measured 2 to 6 h after the start of therapy was associated with increased risk of intubation (HR 4.03 [95% CI 1.18 - 13.7]; p=0.026). CONCLUSION: High-flow therapy is a useful treatment in ARDS in order to avoid intubation or as a bridge therapy, and no increased mortality was observed secondary to the delay in intubation. After initiating HFNC, a ROX index below 4.94 predicts the need for intubation.

Acetazolamide Therapy for Metabolic Alkalosis in Pediatric Intensive Care Patients.

OBJECTIVE: Patients in PICUs frequently present hypochloremic metabolic alkalosis secondary to loop diuretic treatment, especially those undergoing cardiac surgery. This study evaluates the effectiveness of acetazolamide therapy for metabolic alkalosis in PICU patients. DESIGN: Retrospective, observational study. SETTING: A tertiary care children's hospital PICU. PATIENTS: Children receiving at least a 2-day course of enteral acetazolamide. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Demographic variables, diuretic treatment and doses of acetazolamide, urine output, serum electrolytes, urea and creatinine, acid-base excess, pH, and use of mechanical ventilation during treatment were collected. Patients were studied according to their pathology (postoperative cardiac surgery, decompensated heart failure, or respiratory disease). A total of 78 episodes in 58 patients were identified: 48 were carried out in cardiac postoperative patients, 22 in decompensated heart failure, and eight in respiratory patients. All patients received loop diuretics. A decrease in pH and PCO2 in the first 72 hours, a decrease in serum HCO3 (mean, 4.65 ± 4.83; p < 0.001), and an increase in anion gap values were observed. Urine output increased in cardiac postoperative patients (4.5 ± 2.2 vs 5.1 ± 2.0; p = 0.020), whereas diuretic treatment was reduced in cardiac patients. There was no significant difference in serum electrolytes, blood urea, creatinine, nor chloride after the administration of acetazolamide from baseline. Acetazolamide treatment was well tolerated in all patients. CONCLUSIONS: Acetazolamide decreases serum HCO3 and PCO2 in PICU cardiac patients with metabolic alkalosis secondary to diuretic therapy. Cardiac postoperative patients present a significant increase in urine output after acetazolamide treatment.

Citrate anticoagulation for CRRT in children: comparison with heparin.

Regional anticoagulation with citrate is an alternative to heparin in continuous renal replacement therapies, which may prolong circuit lifetime and decrease hemorrhagic complications. A retrospective comparative cohort study based on a prospective observational registry was conducted including critically ill children undergoing CRRT. Efficacy, measured as circuit survival, and secondary effects of heparin and citrate were compared. 12 patients on CRRT with citrate anticoagulation and 24 patients with heparin anticoagulation were analyzed. Median citrate dose was 2.6 mmol/L. Median calcium dose was 0.16 mEq/kg/h. Median heparin dose was 15 UI/kg/h. Median circuit survival was 48 hours with citrate and 31 hours with heparin (P = 0.028). 66.6% of patients treated with citrate developed mild metabolic alkalosis, which was directly related to citrate dose. There were no cases of citrate intoxication: median total calcium/ionic calcium index (CaT/I) of 2.16 and a maximum CaT/I of 2.33, without metabolic acidosis. In the citrate group, 45.5% of patients developed hypochloremia and 27.3% hypomagnesemia. In the heparin group, 27.8% developed hypophosphatemia. Three patients were moved from heparin to citrate to control postoperatory bleeding. In conclusion citrate is a safe and effective anticoagulation method for CRRT in children and it achieves longer circuit survival than heparin.

Postoperative neutrophil gelatinase-associated lipocalin predicts acute kidney injury after pediatric cardiac surgery*.

OBJECTIVE: We investigated the temporal pattern and predictive value of neutrophil gelatinase-associated lipocalin for early identification of acute kidney injury in children undergoing cardiac surgery. DESIGN: Prospective observational cohort study. SETTING: One PICU in a tertiary medical center in Madrid, Spain. PATIENTS: One hundred six children older than 15 days and younger than 16 years undergoing surgery for congenital cardiac lesions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Urine samples were obtained before and at intervals after surgery. Acute kidney injury was defined according to pediatric Risk, Injury, Failure, Loss, and End-stage kidney disease criteria. The temporal pattern of both urine neutrophil gelatinase-associated lipocalin absolute concentration elevation and normalized to urine creatinine concentration was correlated with the development of acute kidney injury and other clinical outcomes. We evaluated the predictive ability of both urine neutrophil gelatinase-associated lipocalin and urine neutrophil gelatinase-associated lipocalin/creatinine by area under the curve, when added to a clinical predictive model. Data from 106 pediatric patients were analyzed. Acute kidney injury occurred in 42 patients (39.6%). Urine neutrophil gelatinase-associated lipocalin significantly increased in patients with acute kidney injury at 1, 3, and 15 hours postoperatively. Urine neutrophil gelatinase-associated lipocalin and urine neutrophil gelatinase-associated lipocalin/creatinine correlated with surgical variables and clinical outcomes. Acute kidney injury prediction improved when urine neutrophil gelatinase-associated lipocalin was added to a clinical model (area under the curve increased at 1 hr from 0.85 to 0.91 and at 3 hr to 0.92). Neither the urine neutrophil gelatinase-associated lipocalin nor the urine neutrophil gelatinase-associated lipocalin/creatinine values were significantly different between patients with prerenal and sustained acute kidney injury. CONCLUSIONS: Urine neutrophil gelatinase-associated lipocalin is a predictive biomarker for acute kidney injury after pediatric cardiac surgery, and it may permit earlier intervention that improves outcome of acute kidney injury. Urine neutrophil gelatinase-associated lipocalin normalized to urine creatinine improves the prediction of acute kidney injury severity but offers no advantage in acute kidney injury diagnosis.

Electrolyte disturbances in acute pyelonephritis.

The aim of this study was to determine whether renal unresponsiveness to aldosterone associated with hyperkalemia is present in infants with acute pyelonephritis in the absence of significant urinary tract anomalies and to describe the clinical characteristics of patients presenting an inadequate renal response to hyperkalemia. The patient cohort comprised 113 infants with acute pyelonephritis (APN), based on the criteria of a temperature >38°C and significant bacteriuria. Serum and urine electrolytes, creatinine, osmolality, and renal tubular function tests were performed at diagnosis. The findings were compared to those present in 75 children who had fever without significant bacteriuria. Hyperkalemia (>5.5 mmol/L) was observed in infants with an APN diagnosis, who exhibited a lower transtubular potassium concentration gradient (TTKG) and a higher fractional sodium excretion. We defined inadequate renal response to hyperkalemia as the combination of hyperkalemia and TTKG below the normal range established for the age of the subject. Infants presenting an inadequate response to hyperkalemia were younger and associated more frequently with an APN diagnosis. This alteration could be explained by the renal interstitial inflammation present in acute pyelonephritis and the immaturity of the renal tubular responsiveness to aldosterone due to infancy in the absence of urinary tract infection or obstruction.