Clinical trial NCT02714556: Changes in Ventilation Inhomogeneity and Respiratory Function Following Elective Caesarean Section Under Regional Anaesthesia
Official title: Changes in Ventilation Inhomogeneity and Respiratory Function Following Elective Caesarean Section Under Regional Anaesthesia: a Prospective Observational Study
Study type: OBSERVATIONAL
Overall status: WITHDRAWN
Conditions: Pregnancy
Keywords: Lung volume
Lung Clearance Index
Functional Residual Capacity
Respiratory function
Lead sponsor: University Hospital, Geneva
Sponsor class: OTHER
First posted: 2016-03-21
Enrollment: 0
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Pregnant women scheduled for elective caesarean section in gestational weeks 37-40

Brief summary: Pregnancy is associated with physiological changes affecting the cardiorespiratory system as a consequence of an increase in both cardiac output and intra-abdominal pressure. The aim of this prospective observational study is to examine the perioperative changes in ventilation inhomogeneity and respiratory function measured by the non-invasive nitrogen multiple breath washout and forced oscillation techniques.

Detailed description: Pregnancy is associated with physiological changes affecting the cardiorespiratory system as a consequence of an increase in both cardiac output and intra-abdominal pressure. These alterations lead to a ventilation/perfusion mismatch which is potentiated by a decrease in functional residual capacity (FRC). These effects explain why pregnant women are more prone to the occurrence of hypoxemia, particularly in the third trimester of their pregnancy. The importance of the ventilation inhomogeneity can be estimated from the lung clearance index (LCI) measured by the non-invasive nitrogen multiple breath washout (N2 MBW) technique. Moreover the loss in lung volume is associated with reduction in respiratory system compliance, which can also be assessed non-invasively by the forced oscillation technique (FOT).

To our knowledge, there is no existing data on LCI or FRC using the aforementioned techniques in pregnant women. Furthermore, existing data on respiratory function in pregnant women is largely restricted to spirometric and body plethysmographic measurements taken primarily in the 1970s-1980s. As such, the important roles of lung ventilation inhomogeneity as well as the potential changes following birth after caesarean section have yet to be completely characterised.

Eligibility criteria: Inclusion Criteria:

* Written informed consent
* Pregnant woman in the third trimester (37-40 weeks gestational age)
* Scheduled for elective caesarean section under regional (spinal or combined spinal-epidural) anaesthesia

Exclusion Criteria:

* Pregnant women outside 37-40 weeks gestational age
* Non-singleton pregnancy
* Previous history of ≥2 caesarean sections
* History or clinical signs of cardiopulmonary disease in the last 12 months (chronic hypertension, gestational hypertension, preeclampsia, asthma, acute or chronic bronchitis, others)
* Positive current smoking status
* Pre-pregnant body mass index (BMI) \>30 kg/m2 (based on booking records)
* Respiratory infection \<2 weeks prior to surgery
* Inability to perform the respiratory function tests

Primary outcomes:
measure: Perioperative changes in ventilation inhomogeneity (LCI) following delivery by caesarean section
timeFrame: 1-3 days prior to caesarean section until 5 days postoperative
Secondary outcomes:
measure: Alterations in FRC throughout the postpartum period
timeFrame: 1-3 days prior to caesarean section until 5 days postoperative
measure: Changes in respiratory mechanics: respiratory system compliance (Crs)
timeFrame: 1-3 days prior to caesarean section until 5 days postoperatively
measure: Changes in respiratory mechanics: airway resistance (Raw)
timeFrame: 1-3 days prior to caesarean section until 5 days postoperatively
measure: Perioperative respiratory complications
timeFrame: During caesarean section until 5 days postoperatively
measure: Perioperative respiratory interventions
timeFrame: During caesarean section until 5 days postoperatively
Other outcomes:
Locations:
city: Geneva
country: Switzerland
facility: University Hospitals of Geneva
Study officials:
affiliation: University of Geneva
name: Walid Habre, MD, PhD
role: STUDY_DIRECTOR
References: