## 4 Use Case
### Risk Identification Study  
It is standard practice in HAZOP to assemble a team of experts for the risk identification process within a facility or during specific processes [48]. However, this was not necessary in the present case, as the application example was based on the actions recommended by the medical team [25]. Table 2 consolidates information on the evaluated parameters, including the definition of guide words and deviations, with consideration given to the measurement resources. The information provided is based on the thrombosis adherence points in the device [25]. An adverse activity was designated for each thrombosis adherence point in the device, facilitating the study of the undesirable events that arise from thrombosis adherence in three distinct regions, leading to the conception of an adverse process (AE1). Table 3 presents information on the adverse process (AE1), the associated adverse activities ((AE1.1), (AE1.2), and (AE1.3)), and their respective causes. Once the complete description of the parameters evaluated in the adverse process AE1 was established, the risks involving the occurrence of pre-pump thrombosis were identified, and the recommended actions for each undesirable state were specified. Table 4 presents the risk identification results and the medical team's recommended actions for the adverse activity 'pre-pump thrombosis (AE1.1)'. Table 5 presents the results of risk identification and the survey of recommended actions by the medical team for the adverse activity 'intra-pump thrombosis (AE1.2)'. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Guide Word** & **Deviation** & **Cause** & **Detection** & **Consequence** & **Recommended Actions** \\ \hline \multirow{2}{*}{Yes} & Symptoms of HF or & & Medical & Evaluate and correct hypovolemia, \\  & persistent low flow & & evaluation & arrhythmia, or hypertension \\ \hline \multirow{2}{*}{Less} & Acute decrease in & Pre-pump & \multirow{2}{*}{Analysis of \multirow{2}{*}{}} & \multirow{2}{*}{Obstruction of \multirow{2}{*}{}} \\  & blood flow & & & \\ \hline \multirow{2}{*}{Less} & Acute decrease in & & & \\  & power consumption & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: HAZOP table for pre-pump thrombosis (AE1.1). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Adherence Point** & **Parameter** & **Guide Word** & **Deviation** \\ \hline
1 & Heart failure (HF) & Yes & Symptoms of HF \\ \hline
1 & Blood flow & Less & Acute decrease in blood flow \\ \hline
1 & Electrical power consumption & Less & Acute decrease in energy consumption \\ \hline
2 & Electrical power consumption & More & Increased energy consumption \\ \hline
2 & Hemolysis & Yes & Symptoms of hemolysis \\ \hline
2 & Third harmonic (acoustic analysis) & Yes & Presence of third harmonic \\ \hline
2 & Heart failure (HF) & Yes & Symptoms of HF \\ \hline
2 & Severe hemolysis & Yes & Symptoms of severe hemolysis \\ \hline
3 & Blood flow & Less & Slow decrease in blood flow \\ \hline
3 & Electrical energy consumption & Less & Slow decrease in electrical power consumption \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Thrombosis adherence points, parameters, guide words, and HAZOP deviations. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Adverse Process** & **Adverse Activity** & **Cause** \\ \hline \multirow{4}{*}{Thrombosis in the device (AE1)} & Pre-pump thrombosis (AE1.1) & Thrombosis in the inflow cannula \\ \cline{2-3}  & Intra-pump thrombosis (AE1.2) & Thrombosis adhered to the rotor \\ \cline{2-3}  & Post-pump thrombosis (AE1.3) & Thrombosis in the outflow cannula \\ \cline{2-3}  & Thrombosis in the anastomosis (aorta and outflow cannula) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Adverse process, adverse activities, and causes. Medical evaluation is required for a conclusive diagnosis of all three adverse activities. The evaluated parameters are derived from indirect detection and are used in identifying deviations, among which the following are highlighted:  
* Acoustic vibration analysis. * Symptoms of hemolysis.