Traction force measurement in vacuum extractions and the Kristeller manoeuvre – a pilot project using digitalised measurements

Introduction The Kristeller manoeuvre (KM) is controversially discussed. It is a manoeuvre where manual force is applied to the mother"s abdomen in the direction of the birth canal during active labour; to assist vaginal delivery. It is usually applied in cases of maternal exhaustion or fetal distress. When used during vacuum assisted delivery it is thought to reduce the traction force on the child"s head, in order to reduce the risk of intracranial hemorrhage and other complications that can arise, if too much force is applied on the vacuum suction. As there is insufficient evidence on the benefits and harms of the KM, concerns of physical and emotional damage being applied to the mother and perhaps even the child without clinical evidence of benefit are being stated. In this study we conceptualize a model for a clinical study aiming to prove the reduction of traction force on the child"s head during vacuum delivery using the KM. Our goal is to develop a reliable model for clinical trials using digitalised force monitoring and a standardised procedure of measurement.

Materials and methods We conducted a series of measurements in a standardized and optimized practice. We used the loadsol/loadpad system by novel developed to measure forces acting on humans. The loadsol/loadpas systems are textile, capacitive force sensors usable for static and dynamic measurements of force applied between two objects. The system measures the force and communicates via Bluetooth with a receiver on which the data can be stored, analyzed and displayed. Our systems were constructed especially for our intended uses. One sensor which can be attached to a glove for the force measurement of KM and one sensor which can be applied to the handle of the Kiwi vacuum extraction system were designed [1] [2].

We practiced vaginal vacuum extraction on a model with and without the help of KM. In test trails both delivering physicians – the one performing vacuum extraction as well as the one performing KM – were experienced in these procedures.

The traction force profiles of the vacuum traction with and without help of KM were compared within the delivering physicians and between them.

Results In test trails the vacuum traction force was up to 24% lower when simultaneous KM was performed. The time needed for vacuum delivery was reduced by up to 43% with simultaneous KM. The appliance of KM resulted in a lower number of disengagements of the vacuum.

Discussion Our results show that there might be in fact a reduction of traction force on the fetal head during vacuum extraction by performing simultaneous KM.

Clinical trials on real births will be needed to reinforce our findings. The resulting possible reduction of side effects and complications in the delivered infants also needs to be investigated.

Our present study can be used as a model to develop standardised procedures in such future clinical trials.

 

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• References

• 1 Hayata et al, TJOG, 2018
• 2 Hofmeyr et al, CDSR, 2017

Publikationsverlauf

Artikel online veröffentlicht:
15. November 2023