A nurse is caring for a 6-month-old child. The child's provider has ordered a diphtheria, tetanus, and pertussis (DTaP) vaccine to be administered. Which of the following should cause the nurse to question the administration of this vaccine?

A. Decreased hematocrit: Hematocrit usually increases in dehydration due to the concentration of red blood cells in a smaller volume of plasma.

B. Increased respiratory rate: Dehydration can lead to tachypnea (increased respiratory rate) as the body attempts to compensate for the decreased blood volume and maintain oxygen delivery.

C. Decreased heart rate: Dehydration typically causes tachycardia (increased heart rate) as the body tries to maintain adequate blood circulation and pressure.

D. Increased platelet count: Dehydration does not typically affect platelet count significantly, though it may concentrate blood components, including platelets, making them appear elevated on a lab test.

Increased seizure activity

• Finding: Phenytoin level

The child's phenytoin level is 6 mcg/mL, which is below the therapeutic range of 10-20 mcg/mL. Subtherapeutic levels of phenytoin mean the medication is not providing adequate seizure control, increasing the risk of more seizures. The recent seizure history and the low drug level indicate a direct correlation between insufficient phenytoin levels and increased seizure activity.

Pneumonia

• Finding: Cough

A harsh, non-productive cough that worsens with activity and at night can be indicative of respiratory conditions, including asthma exacerbations. However, in the context of this child's history and symptoms, there is no evidence of a productive cough, fever, or other signs of infection that would typically suggest pneumonia. Hence, pneumonia is not the primary concern.

Liver failure

• Finding: Skin rash

Liver failure is usually associated with jaundice, elevated liver enzymes, and systemic symptoms like fatigue or confusion. The child’s liver function tests are within normal ranges, and there are no signs of jaundice or systemic illness. The skin rash is more likely related to eczema or a possible drug reaction rather than indicating liver failure.

Steven-Johnson syndrome

• Finding: Liver enzymes

Steven-Johnson syndrome (SJS) is a severe skin reaction typically triggered by medications, including anticonvulsants. Elevated liver enzymes can be seen in SJS, but the child’s liver enzymes are within normal ranges. The rash described does not match the characteristics of SJS, which typically presents with widespread, painful, blistering rashes, not localized eczema patches. Therefore, SJS is unlikely in this scenario.

Pneumothorax

• Finding: Lung sounds

A pneumothorax would usually present with decreased breath sounds, possibly on one side, along with signs of respiratory distress such as tachypnea and cyanosis. The child has slight end expiratory wheezes but normal respiratory rates and oxygen saturation, which suggests asthma rather than pneumothorax. Therefore, pneumothorax is not a primary concern here.