Cerebrospinal Acid-base in Pregnant and Non-pregnant Fertile Women
- Conditions
- Respiratory AlkalosisCerebrospinal FluidPregnancyAcid-Base Imbalance
- Interventions
- Diagnostic Test: Acid - Base characterization
- Registration Number
- NCT03496311
- Brief Summary
The third trimester of pregnancy is typically characterized by the development of a marked respiratory alkalosis. The possible role of pregnancy-induced variations of cerebrospinal fluid (CSF) acid-base characteristics on the development of hypocapnic alkalosis is still unknown.
Aim of this study is to characterize, according to Stewart's approach, the acid-base equilibrium of CSF and arterial plasma of pregnant women and compare the results with data obtained from fertile, non-pregnant women.
- Detailed Description
The reduction in plasma PCO2 correlates with gestational age and was shown to be associated to plasma progesterone concentrations. We hypothesize that pregnancy-related haemodilution, inducing a reduction in CSF Strong Ion Difference (SID), might have a role in the development of pregnancy-related hypocapnic alkalosis.
Samples of CSF and arterial plasma of pregnant women with gestational age \> 35 weeks undergoing spinal anesthesia for elective caesarean section will be analyzed for blood gases, pH, electrolytes, osmolality, albumin and haemoglobin concentration. In addition plasma copeptin levels will be analyzed. The same measurements will be performed in fertile, non-pregnant women undergoing spinal anesthesia for elective surgery.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- Female
- Target Recruitment
- 40
- Pregnancy with gestational age > 35 weeks
- Scheduled elective cesarean section under spinal anesthesia
- known respiratory or neurologic disease
- multiple pregnancies
Study & Design
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Arm && Interventions
Group Intervention Description Control Group Acid - Base characterization Fertile, non-pregnant women undergoing spinal anesthesia for elective surgery. Pregnant Women Acid - Base characterization Pregnant women with gestational age \> 35 weeks undergoing spinal anesthesia for elective cesarean section.
- Primary Outcome Measures
Name Time Method Strong Ion Difference 1 day Strong Ion Difference (expressed in milliequivalents per Liter \[mEq/L\]) of cerebrospinal fluid and arterial plasma
- Secondary Outcome Measures
Name Time Method Partial pressure of carbon dioxide (PCO2) 1 day PCO2 (expressed in millimeters of Mercury \[mmHg\]) of cerebrospinal fluid and arterial plasma
Sum of albumin (expressed in mmol/L) and Phosphates (expressed in mmol/L) 1 day The total amount of weak non carbonic acids, i.e. the sum of albumin and phosphates (both expressed in mmol/L) of cerebrospinal fluid and arterial plasma
Difference between cerebrospinal fluid and arterial plasma Strong Ion Difference (Delta SID) 1 day The difference between plasma and cerebrospinal fluid SID (expressed in mEq/L) will be calculated as marker of electrolyte inbalance between these two extracellular fluid compartments. Delta SID = SIDcsf - SIDplasma
Difference between cerebrospinal fluid and arterial plasma partial pressure of CO2 (Delta PCO2) 1 day The difference between cerebrospinal fluid and arterial plasma PCO2 (expressed in mmHg) will be calculated as a marker of acid-base equilibrium between these two extracellular fluid compartments. Delta PCO2 = SIDplasma - SIDcsf
Progesterone levels 1 day Plasma and CSF Progesterone levels (expressed in ng/mL) will be measured
Copeptin levels 1 day Plasma copeptin levels (expressed in pmol/L) will be measured as a marker of antidiuretic hormone activity
Trial Locations
- Locations (1)
Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico
🇮🇹Milan, Italy