Clinical trial NCT03496311: Cerebrospinal Acid-base in Pregnant and Non-pregnant Fertile Women
Official title: Effects of Pregnancy on the Physico-chemical Characteristics of Cerebrospinal Acid-base Equilibrium
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Acid-Base Imbalance
Respiratory Alkalosis
Cerebrospinal Fluid
Pregnancy
Lead sponsor: Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico
Sponsor class: OTHER
Collaborators: name: University of Milan
First posted: 2018-04-12
Enrollment: 40
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: CASE_CONTROL
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Women undergoing spinal anesthesia either for elective cesarean section of for elective surgery.

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.

Eligibility criteria: Inclusion Criteria:

* Pregnancy with gestational age \> 35 weeks
* Scheduled elective cesarean section under spinal anesthesia

Exclusion Criteria:

* known respiratory or neurologic disease
* multiple pregnancies

Primary outcomes:
measure: Strong Ion Difference
timeFrame: 1 day
Secondary outcomes:
measure: Partial pressure of carbon dioxide (PCO2)
timeFrame: 1 day
measure: Sum of albumin (expressed in mmol/L) and Phosphates (expressed in mmol/L)
timeFrame: 1 day
measure: Difference between cerebrospinal fluid and arterial plasma Strong Ion Difference (Delta SID)
timeFrame: 1 day
measure: Difference between cerebrospinal fluid and arterial plasma partial pressure of CO2 (Delta PCO2)
timeFrame: 1 day
measure: Progesterone levels
timeFrame: 1 day
measure: Copeptin levels
timeFrame: 1 day
Other outcomes:
measure: SID PCO2 correlation
timeFrame: 1 day
measure: Osmolality PCO2 correlation
timeFrame: 1 day
measure: Plasma progesterone PCO2 correlation
timeFrame: 1 day
measure: CSF progesterone PCO2 correlation
timeFrame: 1 day
Locations:
city: Milan
country: Italy
facility: Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico
Study officials:
affiliation: University of Milan
name: Thomas Langer, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: University of Milan
name: Antonio Pesenti, MD
role: STUDY_DIRECTOR
affiliation: Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico di Milano
name: Edoardo Calderini, MD
role: STUDY_CHAIR
affiliation: University of Milan
name: Giorgio Giudici, MD
role: STUDY_CHAIR
affiliation: Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico di Milano
name: Mariateresa Ambrosini, MD
role: STUDY_CHAIR
References:
citation: Zadek F, Giudici G, Ferraris Fusarini C, Ambrosini MT, di Modugno A, Scaravilli V, Zanella A, Fumagalli R, Stocchetti N, Calderini E, Langer T. Cerebrospinal fluid and arterial acid-base equilibria in spontaneously breathing third-trimester pregnant women. Br J Anaesth. 2022 Nov;129(5):726-733. doi: 10.1016/j.bja.2022.07.048. Epub 2022 Sep 10.