Perioperative fluid therapy has undergone a huge change in clinical practice in recent years. The patterns of replacement and / or restoration of volemia described in the classic anaesthesiology books were supported by weak scientific evidence, and a paradigm shift in perioperative fluid therapy based on aspects such as increased mortality associated with an excessively positive balance of fluids in the perioperative period, evidences related to the non-existence of the third non-anatomical space and the need to preserve the capillary endothelium and its glycocalyx.

On the other hand, advances in technology, through the availability of less invasive monitoring systems, capable of determining dynamic parameters related to blood volume that allow predicting the response to volume management, have provided much more adequate monitoring and simple to guide such intravenous volume restoration.

Following all these changes different guidelines and recommendations have been published in recent years with the intention of clarifying the current evidence and facilitate the correct use of fluid therapy to clinicians, but despite this the fact is that today the investigators still do not have information on how fluid therapy is administered in daily practice, so the section of Hemostasis, Transfusion Medicine and Fluid Therapy of SEDAR, considered it necessary to evaluate the clinical practice of fluid therapy in the perioperative period through the Fluidday study.

Background: The administration of fluids in the perioperative period is a routine clinical practice that sometimes underestimates the repercussion of its correct administration.

According to the guidelines of the Spanish Society of Anesthesiology, Resuscitation and Therapy of Pain (SEDAR), the objective of perioperative fluid therapy is to maintain the organism with an optimal state of tissue perfusion and hydration.

This goal is not always easy to carry out. The continuous changes in surgical and anesthetic techniques and the appearance of new fluids and monitoring devices make it difficult for the anesthesiologist to carry out all these changes in his daily clinical practice. For this reason, SEDAR and other international scientific societies have recently published guidelines on the management of fluid therapy in the perioperative period, with the intention of facilitating the decision making of the anesthesiologist in their usual clinical practice based on current evidence. Also adding the recent withdrawal and commercial suspension of a special type of fluid such as Hydroxyethylstarch.

Hypothesis: Fluid therapy in the surgical environment is administered in a protocolized manner and in accordance with the recommendations of the different clinical practice guidelines.

Objectives: To evaluate the management of fluid therapy by anesthesiologists in adult patients during the perioperative period of scheduled and urgent surgery, taking into account the types of fluids administered, the monitoring used and the application of guided therapy protocols by objectives.

Methods: A multicenter prospective observational cross-sectional study - 24-hour Prevalence Cut off is proposed to evaluate the fluid therapy administered by anesthesiologists in surgical patients. The study will be carried out simultaneously in all hospitals that decide to participate throughout the Spanish territory and the follow-up period will be a maximum of 24 hours. Two different intersemanial days will be chosen to include the maximum number of episodes and types of surgeries.

Relevance: The clinical practice guidelines with their recommendations or suggestions offer a safety tool for patients based on current scientific evidence, hence the importance of its correct implementation. Sometimes problems of dissemination of information or limitations in the application of the same can cause that these objectives are not met.

From the Section of Hemostasis, Transfusion Medicine and Fluid Therapy of the SEDAR, it is intended to assess the implementation and follow-up of the recommendations and / or suggestions issued in the different clinical practice guidelines for the correct management of Fluid Therapy in the perioperative setting by performing of this study. This will allow locating the points of improvement in the usual clinical practice on perioperative fluid therapy and will contribute on the one hand to the implementation of the different clinical practice guidelines and, on the other hand, it will serve as a base material for the development of future lines of research.

Inclusion Criteria:

• Patients over 18 years of age surgically treated during the 24 hours of the two-day study of both scheduled and emergency surgery.

Exclusion Criteria:

• Interventions performed outside the surgical area: complementary examination cabinets.
• Interventions that do not require the presence of an anesthesiologist.
• Ophthalmologic surgery
• Surgery performed with local anesthesia.

Study population The fluid therapy administered by the anesthesiologists (Operating Room, PACU and resuscitation and critical units) will be recorded for all patients who are operated during the 24 hours of the study and who meet the inclusion criteria. The 24 hours of registration will be defined as the interval of 08:00 a.m. of the chosen day until 08:00 a.m. of the next day.

Participation in this study only involves conducting an interview and collecting data from your clinical record referring to the 24 hours after your intervention, without making any additional intervention.

Approval of the study by the AEMPS and the CEIC of the Bellvitge University Hospital February - March 2018.

Throughout this period of time, the promotion and inclusion of the different participating centers will be carried out. In addition to simultaneously performing the online database by the Statistics Department of the IDIBELL Foundation - Barcelona.

Obtaining the approvals of the CEICS and relevant entities.

It is expected that the days to make the cut can be done in February 2019.

Subsequently, the statistical analysis will be carried out and the results will be presented at the Meeting of the Haemostasis, Transfusion Medicine and Fluid Therapy Section of the SEDAR in 2019 and the results will be sent to the journal that is deemed appropriate for publication.

At the end of 2019