the efficacy of maternal oxygen inhalation for fetal growth restriction

JRCT ID: jRCTs051240145

Registered date:03/10/2024

Basic Information

• Recruitment status: Recruiting
• Health condition(s) or Problem(s) studied: Fetal growth restriction
• Date of first enrollment: 03/10/2024
• Target sample size: 20
• Study type: Interventional

Intervention(s)

Maternal oxygen inhalation for about 12 hours every day from 8 am to 8 pm [except for when eating, using the toilet and showering]. We confirm that total oxygen inhalation time for 2 days is 8 hours or more using the oxygen diary.
We start oxygen inhalation at 5 L/min [FiO2 40%] for 2 days. Ultrasound examinations are performed before the inhalation, 8 hours and 12 hours after the start of inhalation, and at the end of inhalation on the 2nd day. Fetal umbilical artery blood flow patterns are compared before the first inhalation with at the end of inhalation on the 2nd day. When we can not confirm the improvement of the fetal umbilical artery blood flow, increase the dose by 1L/min from the day after the end of inhalation [3rd day], inhalation for 2 days. Ultrasound examinations are performed before the start of inhalation, 8 hours and 12hours after the start of inhalation, and at the end of inhalation on the 2nd day. Fetal umbilical artery blood flow patterns are compared before the first inhalation with at the end of inhalation on the 2nd day after increasing the dose [4th day]. When fetal umbilical artery blood flow does not improve, increase the dose by 1L/min from the day after the end of inhalation [5th day], inhalation for 2 days. Fetal umbilical artery blood flow patterns are compared before the first inhalation with at the end of inhalation on the 2nd day after increasing the dose [6th day]. When fetal umbilical artery blood flow improve or the flow do not improve even after increasing the dose to 7L/min [FiO2 60%], we stop inhalation.
The order of worsening of fetal umbilical artery blood flow abnormalities are: 1. Within the umbilical artery diastolic vascular resistance standard 2. Increase in umbilical artery diastolic vascular resistance [pulsatility index >95%tile] 3. Blood flow redistribution [middle cerebral artery vascular resistance pulsatility index/umbilical artery vascular resistance pulsatility index <1.0] 4. Umbilical artery diastolic absent flow 5. Umbilical artery diastolic reverse flow. The improvement is defined as a transition to at least the previous stage [e.g., from 5 to 4] on the 2nd, 4th, or 6th day after the start of oxygen inhalation.
Clinical examinations [blood and urine examinations] and cardiotocogram [daily] are performed within regular clinical management. Ultrasound examinations performed for research purposes are substituted for the ultrasound examinations [twice a week] performed in regular clinical management.
In order to confirm the occurrence of adverse events due to oxygen inhalation and rest, we check for premature constriction of ductus arteriosus during ultrasound examination during oxygen inhalation, and perform pulmonary functional examinations before starting the first oxygen inhalation and within 7 days after the final inhalation. In addition, we check respiratory symptoms such as coughing and difficulty breathing, central nervous system symptoms such as drowsiness, VTE symptoms such as leg edema and pain, and vital signs [blood pressure, heart rate, oxygen saturation] twice a day while the inhalation, and once a day after the inhalation.

Outcome(s)

• Primary Outcome: Improvement rate of Umbilical artery diastolic blood flow abnormalities

Secondary Outcome

Optimal inspired oxygen concentration to improve fetal umbilical artery blood flow abnormalities
Change of fetal umbilical artery blood flow abnormalities 8 hours and 12 hours after starting oxygen inhalation
Changes in fetal hemodynamics [middle cerebral artery, ductus arteriosus, aorta, renal artery, ductus venosus, umbilical vein, inferior vena cava], cardiac function [Tei index, fractional shortening, total cardiac output]
Presence or absence of adverse events [premature constriction of ductus arteriosus, pulmonary functional examination]
Pregnancy outcome [threatened preterm labor, hypertension disorder of pregnancy, preeclampsia, non-reassuring fetal status, and intrauterine fetal death]
Delivery outcome [gestational age of delivery, delivery method, delivery time, amount of blood loss during delivery, birth weight, sex, Apgar score, umbilical artery blood pH, infant's NICU admission, neonatal transient tachypnea, respiratory distress syndrome, artificial ventilation, intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, chronic lung disease, and neonatal death]

Key inclusion & exclusion criteria

• Age minimum: >= 18age old
• Age maximum: Not applicable
• Gender: Female

Include criteria

1. Fetal growth restriction
Estimated fetal body weight is less than or equal to -1.5 standard deviations
2. Age is 18 years or older
3. Gestational age is between 23 weeks and less than 34 weeks
4. Umbilical artery diastolic blood flow abnormalities
5. Written informed consent is obtained

Exclude criteria

1. Lethal fetal anomaly and chromosomal abnormality
2. Maternal and fetal emergencies such as placental abruption, umbilical cord prolapse, non reassuring fetal status, uterine rupture etc
3. Pregnant women with high risk of venous thromboembolism [VTE]
two or more episodes of VTE, undergoing anticoagulant therapy for the treatment or prevention of VTE before pregnancy, one episode of VTE with meeting any of the following criteria: thrombotic predisposition, previous thromboembolism occurred either during pregnancy or while taking estrogen
4. Undesirable to participate in this study

Related Information

• Primary Sponsor: Katsura Daisuke