Active drains Active drains are maintained under suction . They can be under low or high pressure. Closed ( Jackson- Pratt , hemovac drain ) Open (sump drain ). DisadvantagesAdvantages 1. high negative pressure may injure tissue . 2. Drain clogged by tissue . 1. Keep wound dry , efficient fluid removal . 2. Can be placed anywhere . 3. Prevent bacterial ascension. 4. Allows evaluation of volume and nature of fluid.