A pressure indicator for a chest drainage device includes an outer casing with a longitudinal axis and first and second end portions defining first and second openings. A flexible element is disposed inside the outer casing to define a collapsible pressure-holding inner space in fluid communication with the second opening. An indicator element is disposed inside the outer casing configured to translate along the longitudinal axis. The flexible element, indicator element and outer casing together define a variable interior space inside the outer casing in fluid communication with the first opening. A force resistance element is placed in the casing to resist the translation of the indicator element along at least one direction along the longitudinal axis when a pressure differential exists between the first and second openings. The pressure indicator is placed inside the chest drainage device to be viewable from multiple angles.