Changes in Ventilation Inhomogeneity and Respiratory Function Following Elective Caesarean Section Under Regional Anaesthesia

Withdrawn

• Conditions: Pregnancy

• Registration Number: NCT02714556
• Lead Sponsor: Walid HABRE

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.

Study Timeline

• Study First Submitted: 2016-03-01
• Study First Submitted QC: 2016-03-15
• Study First Posted: 2016-03-21
• Study Start: 2016-05
• Status Verified: 2016-10
• Primary Completion: 2016-10
• Study Completion: 2016-10
• Last Update Submitted: 2016-10-30
• Last Update Posted: 2016-11-01

Recruitment & Eligibility

• Status: WITHDRAWN
• Sex: Female
• Target Recruitment: Not specified

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

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Perioperative changes in ventilation inhomogeneity (LCI) following delivery by caesarean section	1-3 days prior to caesarean section until 5 days postoperative	Nitrogen multiple breath washout technique

Secondary Outcome Measures

Name	Time	Method
Alterations in FRC throughout the postpartum period	1-3 days prior to caesarean section until 5 days postoperative	Nitrogen multiple breath washout technique
Changes in respiratory mechanics: airway resistance (Raw)	1-3 days prior to caesarean section until 5 days postoperatively	Forced oscillation technique
Perioperative respiratory complications	During caesarean section until 5 days postoperatively	Apnoea/bradypnoea, oxygen desaturation \<90%/hypoxemia, hypoventilation/atelectasis, pulmonary embolism, incoercible cough
Changes in respiratory mechanics: respiratory system compliance (Crs)	1-3 days prior to caesarean section until 5 days postoperatively	Forced oscillation technique
Perioperative respiratory interventions	During caesarean section until 5 days postoperatively	Intubation, oxygen therapy, bronchodilator, adrenaline, continuous positive airways pressure (CPAP), respiratory physiotherapy

Trial Locations

Locations (1)

University Hospitals of Geneva; 🇨🇭 Geneva, Switzerland