INTRODUCTION: Surgical process models (SPM) are simplified representations of operations and their visualization by surgical workflow management systems (SWMS), and offer a solution to enhance communication and workflow. METHODS: A 1:1 randomized controlled trial was conducted. A SPM consisting of six surgical steps was defined to represent the surgical procedure. The primary outcome, termed "deviation" measured the difference between actual and planned surgery duration. Secondary outcomes included stress levels of the operating team and complications. Analyses employed Welch t-tests and linear regression models. RESULTS: 18 procedures were performed with a SWMS and 18 without. The deviation showed no significant difference between the intervention and control group. Stress levels (TLX score) of the team remained largely unaffected. Duration of operation steps defined by SPM allows a classification of all liver procedures into three phases: The Start Phase (low IQR of operation time), the Main Phase (high IQR of operation time) and the End Phase (low IQR of operation time). CONCLUSION: This study presents a novel SPM for open liver resections visualized by a SWMS. No significant reduction of deviations from planned operation time was observed with system use. Stress levels of the operation team were not influenced by the SWMS.