Here is the design of a clinical trial:

Official Title: Intraoperative Hemodynamic Optimization Using the Hypotension Prediction Index and Its Impact of Tissular Perfusion

Included conditions:
- Intraoperative Hypotension

Study Armgroups:
- {'label': 'Experimental', 'type': 'EXPERIMENTAL', 'description': 'Hemodynamic management will be based on the functional hemodynamic parameters provided by Hemosphere platform with the Acumen IQ sensor, including cardiac output, stroke volume, SVV and Acumen IQ specific parameters: maximal arterial pressure rise (dP/dtmax), dynamic arterial elastance (Eadyn) and HPI\n\nAs a pattern replacement of interstitial space, we will use balanced crystalloid (Isofundin®) at 1-3 ml / kg / h in case of laparoscopic surgery and 5 to 7 ml / kg / h in case of open surgery.\n\nThe protocol of action on the intravascular space will be based on the maintenance of systolic volume with colloids (hydroxyethyl starch - Voluvén®).', 'interventionNames': ['Device: Hemosphere platform® together with the FloTrac Acumen IQ® sensor']}
- {'label': 'Control', 'type': 'OTHER', 'description': 'Hemodynamic management will be based on the functional hemodynamic parameters provided by the HemoSphere platform® with the FloTrac® sensor, including cardiac output (CO), stroke volume (SV), and stroke volume variation (SVV)\n\nAs a pattern replacement of interstitial space, we use balanced crystalloid (Isofundin®) at 1-3 ml / kg / h in case of laparoscopic surgery and 5 to 7 ml / kg / h in case of open surgery.\n\nThe protocol action for the intravascular space will be based on a recently published hemodynamic optimization algorithm (Heming N, Moine P, Coscas R, Annane D. Perioperative fluid management for major elective surgery. British Journal of Surgery. 2020;107:e56-62). The fluid used will be hydroxyethyl starch (Voluven®).', 'interventionNames': ['Device: Hemosphere platform® together with the FloTrac® sensor']}

Interventions:
- {'type': 'DEVICE', 'name': 'Hemosphere platform® together with the FloTrac Acumen IQ® sensor', 'description': 'Clinical platform that, analyzing the pulse wave contour, obtained from the previously catheterized radial artery, is able to make available to the clinician both a continuous monitoring of blood pressure and advanced hemodynamic parameters that help patient management. It incorporates predictive parameters such as the hypotension prediction index and decision support parameters such as dynamic arterial elastance and maximum dP / dT.\n\nIt also has the possibility of assessing regional oxygen saturation, measured by near-infrared light photoplethysmography, and the sensor can be applied in different locations (cerebral, muscular ...).', 'armGroupLabels': ['Experimental']}
- {'type': 'DEVICE', 'name': 'Hemosphere platform® together with the FloTrac® sensor', 'description': 'Clinical platform that, analyzing the pulse wave contour, obtained from the previously catheterized radial artery, is able to make available to the clinician both a continuous monitoring of blood pressure and advanced hemodynamic parameters that help patient management.\n\nIt also has the possibility of assessing regional oxygen saturation, measured by near-infrared light photoplethysmography, and the sensor can be applied in different locations (cerebral, muscular ...).', 'armGroupLabels': ['Control']}

Primary Outcomes:
- {'measure': 'TWA-MAP< 65 mmHg', 'description': 'Area between 65 mmHg threshold and the curve of the MAP measurements divided by the total continuous reading time mmHg for a minimum duration of 1 minute (3 consecutive records from one minute to more between two consecutive falls).', 'timeFrame': 'Intraoperatively'}
- {'measure': 'Number of intraoperative hypotension episodes', 'description': 'defined as an event of MAP \\< 65 mmHg of at least 1-minute duration', 'timeFrame': 'Intraoperatively'}
- {'measure': 'Total time of hypotension per case', 'description': 'Intraoperative Total time of hypotension (MAP \\< 65 mmHg)', 'timeFrame': 'Intraoperatively'}

Please estimate the sample size based on the assumption: 
90% power, 5% significance level, 10% drop-out rate.
Sample size and data analysis
        The literature indicates that a cumulative hypotension time of more than 10âmin during surgery is clinically relevant.25 Given the novelty of the HPI parameter and the lack of publications during the design of this study, a pilot study in 31 patients undergoing major surgery was performed at the Virgen del RocÃ­o Hospital. In this preliminary study, two groups were defined: a control group with invasive and continuous arterial pressure monitoring but without the use of HPI; and an intervention group with invasive and continuous blood pressure monitoring, in which the anaesthesiologist also had access to the HPI value and the additional parameters during surgery. In both groups, the haemodynamic objective during the intraoperative period was to maintain the MAP above 65âmm Hg. The results from this preliminary study revealed that in the control group (15 patients), 68.75% of the patients accumulated more than 10âmin of hypotension (11 patients), while in the intervention group with HPI (16 patients), only 31.25% of the patients accumulated periods of a MAP <65âmm Hg more than 10âmin (5 patients).
        Based on this pilot study, to achieve a 90% power, and a significance level of 5%, 72 patients will be required (36 in each group). Assumed a drop-out rate of 10%, a total of 80 patients will be required (40 patients per group).