Do Changes in Plasma Osmolality Influence Ventilation? (OSM)

Vibeke Moen

Status and phase: Completed; Early Phase 1

Conditions: Hyponatraemia; Hypernatraemia

Treatments: Other: Saline 3%; Other: Water

Study type: Interventional

Funder types: Other

Identifiers

NCT01008644

M-126-09

Details and patient eligibility

About

Primary hypothesis: osmolality changes influence the sensitivity of the respiratory center to carbon dioxide, hyponatraemia causing hyperventilation, and hypernatraemia depressing ventilation.

Secondary hypothesis: There are gender differences in the sensitivity to osmolality changes.

10 women and 10 men will on different occasions drink water or receive hypertonic saline intravenously, in order to lower or increase plasma osmolality. The women will participate during both faces of the menstruation cycle. On each occasion the subject´s sensitivity to carbon dioxide will be tested, and blood samples will be drawn for analysis of blood gases,electrolyte and osmolality.Subjects who interrupt participation before completion of all planned occasions, will be substituted, so that 10 subjects of either sex will have participated as planned. All results from all participants will be analyzed.

Full description

Healthy volunteers will on different occasions be subject to reduced plasma osmolality caused by drinking water, and increased osmolality caused by intravenous infusion of hypertonic saline.Before and after each osmolality change, sensitivity to carbon dioxide will be tested by partial rebreathing through a so called Bain-system. Throughout the whole experiment heart rate, blood pressure and oxygen saturation will be recorded.Blood samples will be collected before each rebreathing test and every 20 minutes during the two hours of water or salt load. Urine will be collected and analysed.

Enrollment: 26 patients

Sex: All

Ages: 18 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Females with regular menstruations, males

Exclusion criteria

• Consumption of nicotine, BMI > 26,
• pregnancy,any hormone treatment,
• treatment with diuretics,
• diabetes or kidney disease,
• BMI > 26,

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Factorial Assignment

Masking: None (Open label)

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26 participants in 2 patient groups

Saline

Experimental group

Description:

The subjects will receive saline 3% intravenously for 2 hours, the volume calculated as 0.1 ml/kg/min.

Treatment:

Other: Water

Other: Saline 3%

Water

Experimental group

Description:

The subjects will drink tap water for 2 hours, the volume calculated as 20ml/kg/hour

Treatment:

Other: Water

Other: Saline 3%