Influence of Perioperative Fluid Therapy on Hemoglobin and Methemoglobin Levels

Study Overview
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Brief Summary
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The objective of the study is to evaluate influence of perioperative fluid therapy on Methemoglobin levels, and to changes in hemoglobin. Further, changes in Methemoglobin will be related to metabolic signs of oxidative stress (changes in blood lactate). Patients undergoing major abdominal surgery will be included into the study.

Detailed Description
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Increasing plasma volume by intravenous administration of crystalloid and/or colloid solutions may cause a relative reduction in hemoglobin (Hb) concentration, a situation that is termed 'dilutional anemia'. Such hemodilution may lead to an iatrogenic reduction in oxygen-carrying capacity and the development of organ dysfunction. Paradoxically, large amounts of fluids that are administered with the aim of increasing oxygen delivery (DO2), as is frequently done as part of perioperative goal-directed therapy; this may lead to an actual decrease in the DO2 due to a decrease in Hb concentration. Another potential parameter that may reflect the development of dilutional anemia is methemoglobin (MetHb), a form of Hb with reduced ability for oxygen binding. Experimental studies showed that dilutional anemia may lead to up-regulation of perivascular nitric oxide synthase (NOS) and increase NOS-derived nitric oxide (NO) leading to local vasodilation and oxidization of Hb to MetHb. MetHb may potentially serve as a biomarker of 'anemic stress' associated with reduced tissue perfusion during acute hemodilution.

Official Title
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Influence of Perioperative Fluid Therapy on Hemoglobin and Methemoglobin Levels in Major Abdominal Surgery

Conditions
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Perioperative/Postoperative Complications, Fluid Overload, Hemoglobin H

Intervention / Treatment
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* Other: GDT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: major abdominal surgery informed consent Exclusion Criteria: violation of study protocol

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| GDT Group<br>receives goal-directed therapy | Other: GDT<br>* individualized fluid therapy<br>|
| Not GDT Group<br>receives no individualized goal-directed therapy | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Influence of perioperative fluid therapy on hemoglobin levels | Influence of perioperative fluid therapy on hemoglobin levels | during surgery | 
| Influence of perioperative fluid therapy on Methemoglobin levels | Influence of perioperative fluid therapy on Methemoglobin levels | during surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Influence of perioperative fluid therapy on changes in lactate | Influence of perioperative fluid therapy on changes in lactate | during surgery | 
| Influence of perioperative fluid therapy on SvO2 | Influence of perioperative fluid therapy on SvO2 | during surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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fluid therapy, perioperative, hemodilution