The backward effect of total heart failure may cause __________________. Select all that apply.

The backward effects of total heart failure can cause the following:

- **Jugular vein distension**: This occurs due to increased pressure in the right atrium, which backs up into the venous system.
- **Paroxysmal nocturnal dyspnea**: Patients may experience sudden shortness of breath while lying down, caused by the accumulation of fluid in the lungs.
- **Pulmonary edema**: The left ventricle's inability to effectively pump blood can lead to fluid buildup in the lungs.
- **Pulmonary crackles**: These are abnormal lung sounds that can indicate fluid in the alveoli, often associated with pulmonary edema.

**Hypertension** is typically not a backward effect of total heart failure; instead, heart failure is usually associated with lower blood pressure.

So, the correct options are:
- Jugular vein distension
- Paroxysmal nocturnal dyspnea
- Pulmonary edema
- Pulmonary crackles