(KTXL) — Buffalo Bills safety Damar Hamlin remains under intensive care after collapsing during a game, but has shown signs of improvement, the team announced Wednesday.

According to the team, Hamlin is currently in critical condition and is expected to remain in the Intensive Care Unit (ICU). Hamlin collapsed on the field during the first quarter of the Bills’ game against the Cincinnati Bengals on Sunday from cardiac arrest after making a tackle. 

CPR and automated external defibrillation (AED) were quickly performed on the field to resuscitate Hamlin before transporting to him a nearby hospital. The game between the Bills and the Bengals has been postponed and the NFL has not announced any plans to resume the game or make changes to its week 18 schedule. 

Dr. Howard Dinh, the Medical Director of Cardiac Services for Kaiser Permanente Greater Sacramento, explained to FOX40’s Richard Sharp what cardiac arrest is and how it’s different than a heart attack. Dinh is also the Chair of Cardiology Chiefs of Kaiser Permanente Northern California.

“The recovery time for anybody after a cardiac arrest is really dependent on how long the heart has stopped,” Dinh said. “Timely CPR and AED is critical in restoring blood flow and oxygen to the rest of the body.”