Postoperative Hyponatremia - Are There Gender Differences?

Study Overview
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Brief Summary
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The proposed study will focus on anesthesia and anesthesia-induced hypotension as a possible cause for postoperative fluid retention and hyponatremia, and investigate gender differences in this response.

Detailed Description
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30 healthy women and 30 healthy men, who are scheduled for surgery of the middle ear or parotic gland are included in the study. Within each gender group, the subjects are randomized to receive perioperative intravenous fluid regimes either based on body weight or lean body mass (LBM). The surgery lasts for at least 3 hours, the intervention period (fluid administration according to protocol) will last 10-12 hours, the study period will be 20-24 hours. Blood samples for analysis of plasma sodium, potassium, glucose and osmolality are collected preoperatively and the following morning together with analysis of urine produced during the study period.

Official Title
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Postoperative Hyponatremia - Are There Gender Differences?

Conditions
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Hyponatremia

Intervention / Treatment
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* Procedure: Fluid administration
* Procedure: Perioperative fluid management based on Lean Body Mass


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA Physical status I-II Subjects scheduled for otorinolaryngoiatric surgery in general anesthesia of at least 3 hours duration Exclusion Criteria: BMI less than 18 BMI greater than 33 Diabetes mellitus requiring medication Treatment with diuretics ACE-inhibitors Angiotensin II antagonists Cortisone Lithium Diseases of the kidney Females: Pregnancy Menopause Endocrine dysfunction influencing menstruation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: I<br>Perioperative fluid management based on body weight | Procedure: Fluid administration<br>* Preoperative: bolus of 10 ml/kg body weight. During operation: 5 ml/kg body weight/hr. Postoperative: 3 ml/kg body weight/hr<br>* Other names: Fluid administration by body weight;|
| Active Comparator: II<br>Perioperative fluid management based on Lean Body Mass (LBM) | Procedure: Perioperative fluid management based on Lean Body Mass<br>* Preoperative: bolus of 12 ml/kg LBM. During operation: 6 ml/kg LBM/hr. Postoperative: 3.5 ml/kg LBM/hr<br>* Other names: Fluid administration by Lean Body Mass;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change between preoperative and postoperative plasma sodium concentration |  | 24 hrs | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Water-Electrolyte Imbalance