Archie who weighs 44 tb has been given an order for amoxilin 500 mg bid to take before a dentist appointment based on his history of infective endocans. The drug test shows that the daily dose of amoecitin is 50 mg/kg/day in two divided doses. What dose in milligrams is safest for this child?

Decreased cardiac output is a common consequence of various cardiac conditions in children. In this scenario, the child's cool extremities and thready pulses indicate poor peripheral perfusion, which can occur when the heart is not effectively pumping blood to meet the body's demands. Decreased urinary output is another sign of poor cardiac output, as reduced blood flow to the kidneys can result in decreased urine production.

The other options may contribute to decreased cardiac output, but they are not the primary factors indicated by the clinical findings:

A. Increased afterload: Increased afterload can make it more difficult for the heart to pump blood effectively, but it is not the primary cause of the symptoms described.

C. Decreased contractility: Decreased contractility can reduce the heart's ability to pump blood, contributing to decreased cardiac output, but it is not the primary factor indicated by the clinical findings.

D. Increased stroke volume: An increase in stroke volume typically results in improved cardiac output, not diminished cardiac output as seen in this scenario.

Coarctation of the aorta is a congenital heart defect where the aorta, the major blood vessel that carries oxygenated blood from the heart to the body, is narrowed. As a result, blood pressure tends to be higher in the arms and upper body but lower in the lower body, including the legs. This condition can lead to symptoms such as dizziness, headaches, and even nosebleeds due to high blood pressure. Weak or absent lower extremity pulses, as well as pale and cool legs, are characteristic physical findings in coarctation of the aorta.

A. Tetralogy of Fallot: This is a different congenital heart defect characterized by a combination of four specific heart defects, including ventricular septal defect, right ventricular hypertrophy, pulmonary stenosis, and an overriding aorta. It typically does not cause the symptoms described in the scenario.
C. Pulmonic Stenosis: This condition involves the narrowing of the pulmonary valve or artery, leading to restricted blood flow from the right ventricle to the pulmonary artery. While it can cause various symptoms, it typically doesn't cause the specific blood pressure discrepancies described.
D. Tricuspid Atresia: This is a congenital heart defect where the tricuspid valve is absent or abnormally developed. It leads to the mixing of oxygenated and deoxygenated blood in the heart. While it can cause cyanosis (bluish skin due to low oxygen levels), it doesn't typically cause the specific blood pressure findings mentioned.