A patient had a pneumonectomy to the right lung performed 48 hours ago. Which of the following conditions most likely exists?

After a pneumonectomy, where a lung is surgically removed, there will be a decrease in breath sound volume on the affected side due to reduced airflow. This reduction in breath sound volume is expected as there is less lung tissue to produce sound. Choices B, C, and D are incorrect. Elevated tidal volume and respiratory capacity are not expected after a pneumonectomy, and wheezing is more commonly associated with conditions like asthma or bronchitis, not a recent pneumonectomy.