Clinical trial NCT01008644: Do Changes in Plasma Osmolality Influence Ventilation?
Official title: Do Plasma Osmolality Changes Influence Ventilation, and Are There Gender Differences?
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: EARLY_PHASE1
Conditions: Hyponatraemia
Hypernatraemia
Keywords: carbon dioxide
ventilation
gender
osmolality
menstruation cycle
Lead sponsor: Kalmar County Hospital
Sponsor class: OTHER
First posted: 2009-11-06
Enrollment: 26
Sex: ALL
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: FACTORIAL
Primary purpose: BASIC_SCIENCE

Brief summary: 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.

Detailed 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.

Eligibility criteria: 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,

Primary outcomes:
measure: pCO2
timeFrame: ten minutes
Secondary outcomes:
Other outcomes:
Locations:
city: Kalmar
country: Sweden
facility: Department of Anaesthesia and Intensive care, Kalmar County Hospital
Study officials:
affiliation: Department of Anaesthesia and Intensive Care , Karolinska University Hospital, Stockholm
name: Lars Irestedt. MD PhD
role: STUDY_DIRECTOR
References:
citation: Jennings DB. The physicochemistry of [H+] and respiratory control: roles of PCO2, strong ions, and their hormonal regulators. Can J Physiol Pharmacol. 1994 Dec;72(12):1499-512. doi: 10.1139/y94-216.
citation: Weissgerber TL, Wolfe LA, Hopkins WG, Davies GA. Serial respiratory adaptations and an alternate hypothesis of respiratory control in human pregnancy. Respir Physiol Neurobiol. 2006 Aug;153(1):39-53. doi: 10.1016/j.resp.2005.09.004. Epub 2005 Nov 28.
citation: Heenan AP, Wolfe LA. Plasma osmolality and the strong ion difference predict respiratory adaptations in pregnant and nonpregnant women. Can J Physiol Pharmacol. 2003 Sep;81(9):839-47. doi: 10.1139/y03-072.