Technical instructions

 

Positioning

Applying the obstetrical iCup® device requires a good understanding of obstetrical mechanics and specialist professional training.

Correctly positioning of the iCup® on the fetal head is essential to ensure that the maneuver is successful. The cup must be applied to the "flexion point". This " flexion point" is located on the sagittal suture 3 cm in front of the posterior fontanelle at thee intersection between the sincipital-chin diameter and the fetal scalp (Figures 2,3. The longer the lever (the distance between the atloid-occipital joint and the occiput) on which the instrument acts, the easier it is to flex the head, and the less traction is required to obtain this flexion (Figure 4).

In practice, the iCup® should be positioned as near to the fetal occiput as possiblel.

Figure 2 : F = "flexion point"

Figure 3 :"ideal" position of the cup

Figure 4 :correctly positioned cup

 

IIf the iCup® is placed too near the point where the fetal spine projects onto the skull, the efficacy of the device is reduced or even totally lost. An error in diagnosing the fetal position can transform the extractor into a deflexion instrument, leading to total dystocia (Figure 5).

Figure 5 :incorrectly positioned cup leading to deflexion

 

 

Angle of traction

The angle of traction depends on 2 factors:

• The type of position of the fetal head
• How high it is in the pelvis

As a result, initially (during flexion), the traction is intended to complete the flexion of the presentation and then during the second stage (descent), it must be applied exactly in line with the natural progression of the fetal head, reproducing as far as possible the mechanics of spontaneous delivery

 

Flexion

The tractions should be gentle and continuous.
First of all, after locating the posterior fontanelle, the cup is applied to the " flexion point ".
Then, depending on the type of position, there are theoretically 6 possible directions of traction:

• LOA: downwards and to the right (Figure 6)
• ROA: downwards and to the left (Figure 7)
• LOT: horizontally and to the right (Figure 8)
• DOT: horizontally and to the left (Figure 9)
• LOP: upwards and to the right (Figure 10)
• ROP: upwards and to the left (Figure 11).

Figure 6 : LOA (traction downwards and to the right)

Figure 7 : ROA (traction downwards and to the left)

Figure 8 : LOT (horizontal traction to the right)

Figure 9 : ROT (horizontal traction to the left)

Figure 10 : ROP (traction upwards and to the right)

Figure 11 : ROP (traction upwards and to the left)

 

Once maximum flexion has been obtained it is sometimes necessary to take the cup off; and reposition it as near to the fetal occiput as possible before embarking on a second phase of traction.
If the flexion of the vertex is correct, there is no need for this first phase of traction. It should also be observed that in the case of an anterior position the direction of traction required to achieve flexion is the same as that used during the second stage of traction.
In the case of posterior or transverse positions, it is usually both possible and sufficient to start the second stage of traction: counter-reaction of the fetal forehead pressing against the anterior arch of the pelvis is sufficient to achieve effective flexion.

Descent

The second stage of traction must reproduce, helping rather than hindering the natural progression of the vertex through the pelvis. The traction is not applied in a single direction, but in different directions depending on the progress of the vertex through the pelvis. We should remember that at all levels in the pelvis, the traction straps must always be perpendicular to the plane of the cup. A slight delay relative to the ideal direction of traction can often be helpful (always tend to pull downwards).
In the inlet pelvic strait (NB: it is not advisable to apply the cup above the interspinous strait), traction is applied along the umbilico-coccygeal axis. When the traction strap of the cup comes into contact with the coccyxn this depresses the posterior perineum. To be able to work effectively, the obstetrician should sit or kneel on the floor, and pull towards his or her feet.

During this second stage, traction must always be perpendicular to the plane of the cup (Figure 12)

 

 

Figure 12 : traction along the umbilico-coccygeal axis (top part engaged)
The traction strap is perpendicular to the plane of the cup

 

NOTE:
• Lateral swaying movements (to the left and then to the right) are not advisable, because they could increase the risk of fetal injury.
• The direction of traction should be raised gradually till it reaches horizontal when the cup appears at the perineum and finally, while still gradually raising the direction of traction, becomes almost vertical when the fetus is expelled
(Figures 13, 14, 15).
• The traction force, which is still moderate, is applied during the uterine contractions, and assisted by the mother's abdominal pushing; between 2 uterine contractions, the obstetrician should simply hold the fetus where it had reached at the last push.
• The descent of the vertex is checked by the finger of the obstetrician's left hand, which remains inside the vagina.

Figure 13 : the various different directions of traction during fetal descent

 

	Figure 14 : traction   1. Traction along the umbilico-coccygeal axis (upper part) 2. Horizontal traction (middle part) 3.Raising the traction (lower part) 4. Raising the traction (perineum) 5. Virtually virtical traction (end of extraction

 

 

Intra-pelvic rotation

The intra-pelvic rotation (Figure 15) induced by the obstetrical cap is simply the rotation induced by the flexion
.

Figure 15 : rotation

 

As far as possible, the landmark point constituted by the special indentation located on the dome of the iCup® intended to fit the obstetrician's finger is positioned towards the fetal occiput. This makes it possible to monitor the rotation of the fetal head as it descends through the pelvis. This rotation occurs spontaneously, assisted by the good cephalic flexion produced by the extraction device.

 

NOTE:

• Do not attempt to turn the cup by twisting to induce rotation. This maneuver is completely ineffective for producing rotation, and would also damage the fetal scalp
• If occipito-pubic rotation is not obtained, the obstetrician is made aware of this by the position of the special indentation on the dome of the iCup®, which remains posterior (if it has been correctly positioned near the fetal occiput). This allows the obstetrician to take the measures required to achieve proper occipito-sacral disengagement.
• Applying the iCup® in an occipito-posterior presentation can make occipito-pubic delivery possible without the more frequent severe perineal injuries and caput succedaneum associated with occipito-sacral disengagement.
• The iCup® makes intra-pelvic rotation possible, and avoids some types of possible injuries of the maternal soft parts. The cup makes it possible to achieve major rotations, which are not advisable using forceps.

Expulsion

The cup can be used to monitor the disengagement millimeter by millimeter between uterine contractions and (by amplifying it) to restore the position of the fetal head after disengagement.

NOTE:

During expulsion, between the uterine contractions, good perineal amplitude is obtained by limited flexion-extension movements of the fetal head obtained using the iCup® (figure 16). However, doing this can exacerbate injuries of the fetal scalp.

 

 

Figure 16 : the cup to produce flexion-extension movements of the fetal head to facilitate perineal ampliation

 

 

Speed and duration of the application of the obstetrical cup

When should one give up?

• After 10 minutes of traction
• After a period time corresponding to five uterine contractions
• After it has been dislodged  twice

If the cup comes of (or "pops off"), this indicates that the cup has not been correctly positioned, that the direction of traction is incorrect, cephalopelvic disproportion or defective vacuum. This never happens suddenly, but is preceded by popping sounds of leakage before the cup actually comes off. If this happens, after checking the type of position (this can be checked using ultrasound in the labor room) and the level of the presentation in pelvic tract, changing the direction of traction can be effective. If the leakage continues, check the parameters of the pump. If the fetal head does not progress, this approach should be abandoned, and a C section carried out without delay.

·      If lesions are produced on the fetal scalp.

 

NOTE: the cardiotocographic recording must also be monitored constantly. Any exacerbation of the recording must lead to the abandonment of the attempt to extract the fetus via the birth canal unless one is sure that it can be done quickly