Answer:
It creates a dramatic effect, with a strong influence of dramatic irony.
Step-by-step explanation:
The fact that Fortunato does not have access to important information, which the reader has access to and which has to do with Fortunato's survival and malaise, gives the reader a strong effect of drama and suspense.
This is explained by the dramatic irony, where the reader knows something and understands that a situation is happening, but the character does not know.