Objective: High-flow nasal cannula oxygen (HFNC) can cause the spread of pathogens. The distance and direction of the droplets connected to HFNC were examined using a simulated device. Method: An experimental system was created using a high-flow nasal therapy device, artificial lung, and medical upper airway manikin that reproduced anatomical structures. The artificial lung and HFNC were started while adjusting variables, such as the flow rate and cannula’s connection direction. Artificial saliva that mimicked oral cavity and airway secretions was applied. Using water-sensitive paper, the maximum scattering distance and the droplet adhesion area were measured. Results: The maximum scattering distance was 191 mm at 60 L/min, and the flight distance increased as the HFNC flow rate increased. The droplets scattered more on the contralateral side of the cannula connection side. Conclusion: In the experimental model, the maximum HFNC use-associated scattering distance is approximately 200 mm, and more droplets may be scattered on the contralateral side of the cannula connection side. Clinically, further studies are needed to determine the distance and direction of droplets.

We describe the details of a case of cardiac arrest and fibrinolytic DIC caused by an anaphylactic reaction to a gadolinium-based contrast agent gadobutrol. An otherwise-healthy woman in her 70s underwent contrast-enhanced MRI for a suspected metastatic brain tumor. At 10 min after administration of the gadobutrol, she experienced cardiac arrest due to anaphylactic shock. She was successfully resuscitated within 12 min. After she was transferred to the ICU, multiple hematomas developed at the sites of venous or arterial lines. Laboratory tests revealed fibrinolytic DIC with fibrinogen 71 mg/dL, FDP 491.4 μg/mL, and D-dimer 26.2 μg/mL, all of which resolved spontaneously. MRI contrast agents are considered safer than iodinated contrast media, but if an anaphylactic reaction occurs, it could be fatal within minutes. Anaphylaxis can also cause fibrinolytic DIC. Health care personnel should be aware of these life-threatening potential adverse reactions to MRI contrast agents and treat the affected patients immediately.