After administering hydromorphone, which clinical manifestation would indicate an adverse reaction?

Respiratory acidosis is a critical clinical manifestation that can indicate an adverse reaction to hydromorphone. This opioid medication is known to cause respiratory depression, which is a reduction in the rate and depth of breathing. When a patient experiences respiratory depression, the level of carbon dioxide in the blood can rise, leading to respiratory acidosis. This condition occurs when the lungs cannot expel carbon dioxide effectively, causing it to accumulate, resulting in a decreased blood pH.

Monitoring the patient's respiratory status after administering opioids like hydromorphone is crucial, as significant respiratory depression may lead to serious complications. If respiratory acidosis is noted, it serves as an alarm for healthcare providers to assess the patient's respiratory function and consider interventions, such as supportive measures or medication adjustments.

The other choices, although they may indicate various health concerns, do not specifically align with the most concerning side effect of hydromorphone. Hypertension, fever, and tachypnea can indicate other medical issues but do not directly represent an adverse reaction specific to opioid administration in the same way respiratory acidosis does.