The main aim of the study was to assess the correlation of intra‑abdominal pressure (IAP) between a direct measurement in the peritoneal cavity and an intermediate one in the bladder. The relation of intra-abdominal pressure measured indirectly in the bladder and directly in the peritoneal cavity was examined. Intra-abdominal hypertension (IAH) exceeding the limit of 12 mm Hg may cause visceral disturbances, leading to dysfunction of the circulatory system, respiratory system and disorders of the secretory functions of the kidneys. Capturing the IAH at the right time based on the clinical picture and related measurements can accelerate the inclusion of appropriate therapeutic procedures, including surgical treatment.