Letter to the Editor: "Use of inhaled epoprostenol with high flow nasal oxygen in non-intubated patients with severe COVID-19".

PURPOSE: Acute lung injury associated with COVID-19 contributes significantly to its morbidity and mortality. Though invasive mechanical ventilation is sometimes necessary, the use of high flow nasal oxygen may avoid the need for mechanical ventilation in some patients. For patients approaching the limits of high flow nasal oxygen support, addition of inhaled pulmonary vasodilators is becoming more common but little is known about its effects. This is the first descriptive study of a cohort of patients receiving inhaled epoprostenol with high flow nasal oxygen for COVID-19. MATERIALS AND METHODS: We collected clinical data from the first fifty patients to receive inhaled epoprostenol while on high flow nasal oxygen at our institution. We compared the characteristics of patients who did and did not respond to epoprostenol addition. RESULTS: The 18 patients that did not stabilize or improve following initiation of inhaled epoprostenol had similar rates of invasive mechanical ventilation as those who improved or stabilized (50% vs 56%). Rates of mortality were not significantly different between the two groups (17% and 31%). CONCLUSIONS: In patients with COVID-19 induced hypoxemic respiratory failure, the use of inhaled epoprostenol with high flow nasal oxygen is feasible, but physiologic signs of response were not related to clinical outcomes.

Insidious Harm of Medication Diluents as a Contributor to Cumulative Volume and Hyperchloremia: A Prospective, Open-Label, Sequential Period Pilot Study.

OBJECTIVES: Although the potential dangers of hyperchloremia from resuscitation fluids continue to emerge, no study to date has considered the contribution of medication diluents to cumulative volume and hyperchloremia. This study compares saline versus dextrose 5% in water as the primary medication diluent and the occurrence of hyperchloremia in critically ill patients. DESIGN: Prospective, open-label, sequential period pilot study. SETTING: Medical ICU of a large academic medical center. PATIENTS: Adult patients admitted to the medical ICU were eligible for inclusion. Patients who were admitted for less than 48 hours, less than 18 years old, pregnant, incarcerated, or who had brain injury were excluded. INTERVENTIONS: Saline as the primary medication diluent for 2 months followed by dextrose 5% in water as the primary medication diluent for 2 months. MEASUREMENTS AND MAIN RESULTS: A total of 426 patients were included, 216 in the saline group and 210 in the dextrose 5% in water group. Medication diluents accounted for 63% of the total IV volume over the observation period. In the saline group, 17.9% developed hyperchloremia compared with 10.5% in the dextrose 5% in water group (p = 0.037), which was statistically significant in multivariable analysis (odds ratio, 0.50; 95% CI, 0.26-0.94; p = 0.031). In the saline group, 34.2% developed acute kidney injury versus 24.5% in the dextrose 5% in water group (p = 0.035); however, this was not statistically significant when adjusting for baseline covariates. No other significant differences in dysnatremias, insulin requirements, glucose control, ICU length of stay, or ICU mortality were observed. CONCLUSIONS: This study identified that medication diluents contribute substantially to the total IV volume received by critically ill patients. Saline as the primary medication diluent compared with dextrose 5% in water is associated with hyperchloremia, a possible risk factor for acute kidney injury.

Na+-K+-Cl- cotransporter (NKCC) maintains the chloride gradient to sustain pacemaker activity in interstitial cells of Cajal.

Interstitial cells of Cajal (ICC) generate electrical slow waves by coordinated openings of ANO1 channels, a Ca2+-activated Cl- (CaCC) conductance. Efflux of Cl- during slow waves must be significant, as there is high current density during slow-wave currents and slow waves are of sufficient magnitude to depolarize the syncytium of smooth muscle cells and PDGFRα+ cells to which they are electrically coupled. We investigated how the driving force for Cl- current is maintained in ICC. We found robust expression of Slc12a2 (which encodes an Na+-K+-Cl- cotransporter, NKCC1) and immunohistochemical confirmation that NKCC1 is expressed in ICC. With the use of the gramicidin permeabilized-patch technique, which is reported to not disturb [Cl-]i, the reversal potential for spontaneous transient inward currents (ESTICs) was -10.5 mV. This value corresponds to the peak of slow waves when they are recorded directly from ICC in situ. Inhibition of NKCC1 with bumetanide shifted ESTICs to more negative potentials within a few minutes and reduced pacemaker activity. Bumetanide had no direct effects on ANO1 or CaV3.2 channels expressed in HEK293 cells or L-type Ca2+ currents. Reducing extracellular Cl- to 10 mM shifted ESTICs to positive potentials as predicted by the Nernst equation. The relatively rapid shift in ESTICs when NKCC1 was blocked suggests that significant changes in the transmembrane Cl- gradient occur during the slow-wave cycle, possibly within microdomains formed between endoplasmic reticulum and the plasma membrane in ICC. Recovery of Cl- via NKCC1 might have additional consequences on shaping the waveforms of slow waves via Na+ entry into microdomains.

Micafungin in the treatment of candiduria: A case series.

Echinocandin antifungal agents are not routinely recommended for the treatment of candiduria due to low urine concentrations and a paucity of clinical data supporting this indication. This report presents five cases describing the use of micafungin for the treatment of candiduria. Each patient received parenteral micafungin for a minimum of 6 days and had resolution of baseline fungal within 30 days of treatment completion.