Final answer:
The most reliable method to determine fluid loss in an infant with bronchiolitis for signs of dehydration is monitoring body weight changes. This direct measure correlates with the loss of tissue water that occurs with dehydration. Other methods like skin turgor and intake/output can provide supplementary information, but they are influenced by other factors.
Step-by-step explanation:
Monitoring for Dehydration in Infants
In the case of an infant with bronchiolitis, monitoring for signs of dehydration is vital as infants are at a higher risk of dehydration compared to adults due to their immature kidneys and their inability to express thirst. Among the methods for determining fluid loss, body weight is considered the most reliable indicator. This is because, during dehydration, there is a loss of tissue water which directly affects body weight. Other methods such as intake and output can provide important data but must be interpreted with caution because of the variable concentration of newborns' urine.
A decrease in Body weight is a very direct measure of water loss, as infants can lose significant weight due to dehydration. Newborns normally lose some weight immediately after birth as they shed fluid; however, excessive weight loss may be indicative of significant dehydration. Skin turgor is another method used to assess hydration, where the skin's elasticity or 'bounce back' after being pinched is observed, but this can be influenced by other factors such as the fat content of the skin. Considering intake and output is also important, especially monitoring how much fluid an infant is taking in against how much urine is being excreted.