Clinical trial NCT03071783: Intra-operative Feed Back on Traction Force During Vacuum Extraction: Safe Vacuum Extraction Alliance
Official title: Intra-operative Feed Back on Traction Force During Vacuum Extraction: a Randomized Control Study of Mid and Low Metal Cup Deliveries.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Hypoxic Ischemic Encephalopathy
Neonatal Convulsions
Subgaleal Hematoma
Lead sponsor: Karolinska Institutet
Sponsor class: OTHER
First posted: 2017-03-07
Enrollment: 800
Sex: FEMALE
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The objective of the clinical investigation is to test whether intra-operative traction force feed back during vacuum extraction leads to a significant decrease in incidence of brain damage in neonates.

By randomization, half of the vacuum extraction patients will be assigned to delivery using a new intelligent handle for vacuum extractions, and half will be assigned to conventional method without traction force measurement.

Detailed description: The most common indications for vacuum extraction are dystocia and/or fetal asphyxia. The safety of assisted vaginal delivery with vacuum extraction has been discussed since its introduction almost fifty years ago. Serious complications such as asphyxia, intracranial hemorrhage and seizures are overrepresented at vacuum extraction compared to spontaneous vaginal delivery.

Little has been done to improve the procedure since the introduction. Safety measures recommended include restricting total time and number of pulls, a full 34 week gestation, and station of the head at the spines or below. A general advice is also to avoid excessive traction force. There is no general agreement to what a safe traction force might be. With exceeding force there seems to be an increased risk for rupture of the sagittal sinus and tearing of the falx at its attachment to the tentorium. Furthermore, when the fetal head is becoming exceedingly elongated and flattened, and as the cup pops off it might cause damage to the brain and blood vessels.

During the procedure the obstetrician is under significant stress and the subjective element of the evaluation of traction force is a concern. The difficult decision of whether to continue a heavy extraction or abort the operation is made under stressful conditions and based mostly on subjective impressions.

To provide the obstetrician with more objective information, the investigators developed a new device consisting of an intelligent handle hooked to the chain of a regular metal cup.

Eligibility criteria: Inclusion Criteria:

* Medical or social reasons for vacuum extraction with a metal cup, gestational age ≥37+0 weeks, singleton, cephalic

Exclusion Criteria:

* Multiple pregnancy, breech presentation, gestational age \<37+0

Primary outcomes:
measure: Composite neonatal brain damage
timeFrame: From start of extraction through 28 days after delivery (or until discharge from the hospital)
Secondary outcomes:
Other outcomes:
Locations:
city: Stockholm
country: Sweden
facility: Karolinska University Hospital
Study officials:
affiliation: Karolinska Institutet
name: Magnus Westgren, Professor
role: PRINCIPAL_INVESTIGATOR
References:
citation: MALMSTROM T. The vacuum extractor, an obstetrical instrument. I. Acta Obstet Gynecol Scand Suppl. 1957;36(suppl 3):5-50. No abstract available.
citation: Moolgaoker AS, Ahamed SO, Payne PR. A comparison of different methods of instrumental delivery based on electronic measurements of compression and traction. Obstet Gynecol. 1979 Sep;54(3):299-309.
citation: Towner DR, Ciotti MC. Operative vaginal delivery: a cause of birth injury or is it? Clin Obstet Gynecol. 2007 Sep;50(3):563-81. doi: 10.1097/GRF.0b013e31811eaa39.
citation: Whitby EH, Griffiths PD, Rutter S, Smith MF, Sprigg A, Ohadike P, Davies NP, Rigby AS, Paley MN. Frequency and natural history of subdural haemorrhages in babies and relation to obstetric factors. Lancet. 2004 Mar 13;363(9412):846-51. doi: 10.1016/S0140-6736(04)15730-9.
citation: Pettersson K, Ajne J, Yousaf K, Sturm D, Westgren M, Ajne G. Traction force during vacuum extraction: a prospective observational study. BJOG. 2015 Dec;122(13):1809-16. doi: 10.1111/1471-0528.13222. Epub 2015 Jan 5.
citation: Romero S, Pettersson K, Yousaf K, Westgren M, Ajne G. Perinatal outcome after vacuum assisted delivery with digital feedback on traction force; a randomised controlled study. BMC Pregnancy Childbirth. 2021 Feb 26;21(1):165. doi: 10.1186/s12884-021-03604-z.