Introduction: The prediction of post- operative bleeding is one of the main tasks of nurses in the intensive care unit. The researcher of the study found that there is not a valuable tool passing through the validation and Clinimetrics process.

Objectives: The present study aimed to design and do the Clinimetrics of post-operative bleeding prediction tool (POPBT) in Intensive Care Unit.

Materials and Methods: This study is a methodological study of Clinical Metric Validation (Clinimetrics), performed on patients undergoing cardiac surgery in Valiasr Hospital, Naja during 2015-2016. Sampling in this study was non-random,, accessible and target oriented. The deductive-inductive approach was used to identify the essence of the structure. Considering the essence of the structure of the bleeding prediction, the designed tool was a kind of combined index. so the tool was designed in two steps based on Wright and Feinstein proposed model. In the first stage, the design of the primary version of the tool (index), and in the second phase of clinical validation (Clinimetrics), initial version of the tool (index) was designed in five steps. Data were analyzed using descriptive and inferential statistics by SPSS.16. It was investigated by the designed tools, its validation-seeking steps including face, content and structure validity and also its reliability were evaluated unanimously

Results: Based on the results of CVI, CVR and Face validity of one item in the pre -operative dimension and 4 items during the operation were retained. Based on these results, the final tool was designed. The CVI of the questionnaire was 80.03. For determining the reliability of tools, 10 nurses in 5 dual groups were applied, kappa coefficient in 5 groups was 0.99, 0.95, 0.99, 0.99, 0.99 and 0.99, respectively.

Discussion and Conclusion: The results of this study showed that the designed tool was favorably reliable and variable for predicting post- operative (heart surgery) bleeding