Final answer:
Due to her severe upper respiratory infection, Harriet with type 1 diabetes is likely to need more insulin to maintain her blood sugar levels as infections increase the body's demand for insulin.
Step-by-step explanation:
Harriet, who has had type 1 diabetes for 20 years, manages her condition with daily injections of NPH and regular insulin. With the development of a severe upper respiratory infection, her body's demand for insulin is likely to increase. This is because infections cause stress in the body, which can lead to a rise in blood sugar levels due to hormones such as adrenaline and cortisol that counteract the effect of insulin. As a result, Harriet may require adjustments to her insulin regimen to maintain optimal blood glucose control during her illness. It is crucial for individuals with type 1 diabetes to monitor their blood sugar levels more frequently when they are sick and to communicate with healthcare professionals for appropriate management.