The variation of FiO2 with circuit type and peak inspiratory flow rate during non-invasive respiratory support using domiciliary ventilators and its significance during the COVID-19 pandemic.

Background: The COVID-19 pandemic has resulted in increased admissions with respiratory failure and there have been reports of oxygen failure and shortages of machines to deliver ventilation and Continuous Positive Airway Pressure (CPAP). Domiciliary ventilators which entrain room air have been widely used during the pandemic. Poor outcomes reported with non-invasive respiratory support using ventilators which lack an oxygen blender could be related to an unreliable Fraction of inspired O2 (FiO2). Additionally, with concerns about oxygen failure, the variety of ventilator circuits used as well as differing peak inspiratory flow rates (PIFR) could impact on the FiO2 delivered during therapy with domiciliary ventilators. Methods: In a series of bench tests, we tested the effect of choice of circuit and different PIFR on the FiO2 achieved during simulation of ventilation and CPAP therapy using domiciliary ventilators. Results: FiO2 was highly dependent upon the type of circuit used with circuits with an active exhalation valve achieving similar FiO2 at lower oxygen flow rates than circuits using an exhalation port. During CPAP therapy, high PIFR resulted in significantly lower FiO2 than low PIFR. Conclusions: This study has implications for oxygen usage as well as delivery of non-invasive respiratory support during therapy with domiciliary ventilators when these are used during the second wave of COVID-19.

Severe clinical toxicity associated with analytically confirmed recreational use of 25I-NBOMe: case series.

CONTEXT: 4-Iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (25I-NBOMe) is a N-methoxybenzyl-substituted phenethylamine with potent serotoninergic effects. We describe seven cases of analytically confirmed toxicity due to the recreational use of 25I-NBOMe in the United Kingdom. CASE SERIES: Seven patients, all young adult males, presented to hospitals in the northeast of England with clinical toxicity after recreational drug use in January 2013. Clinical features included tachycardia (n = 7), hypertension (4), agitation (6), aggression, visual and auditory hallucinations (6), seizures (3), hyperpyrexia (3), clonus (2), elevated white cell count (2), elevated creatine kinase (7), metabolic acidosis (3), and acute kidney injury (1). LC-MS/MS analysis identified 25I-NBOMe as the main active substance in the plasma of all seven cases. CONCLUSIONS: Severe clinical toxicity may occur following recreational use of 25I-NBOMe, with stimulant and serotoninergic features predominating. Clinicians should be alert to this substance, in view of its emergence in Europe as well as in the United States.