The video below details the fetal scalp blood sampling method. The following steps detail how the procedure should be conducted.
- Place the woman either in a lithotomy or left lateral position with her right leg supported and abducted. Then drape the area around the perineum to provide a sterile field.
- Introduce the largest-diameter, lubricated amnioscope that the cervix can accommodate. Direct the amnioscope posteriorly and sweep it anteriorly to catch the anterior lip of the cervix.
- Remove the amnioscope’s obturator and attach your light source. Ideally, the cervix should not be visible. Try to visualise the fetal scalp clearly.
- Clean the fetal scalp with a cottonwool ball dipped in sterile water and spray the scalp with ethyl chloride to produce a reactive hyperaemia.
- Apply a thin film of Vaseline® with a dental roll to increase surface tension on the fetal scalp; this encourages the formation of sizeable droplets of blood.
- Insert a guarded blade into the scalp to the full depth of the guard. Do not stroke the blade across the scalp as this may produce a lesion that is too large.
- Collect the blood droplet into your capillary tube. At least two samples should be obtained. The second may be taken while the first is being analysed by an assistant.
- Apply pressure to the fetal scalp with cottonwool at the end of the procedure if any bleeding is evident.
- Reposition the mother comfortably and explain the results to her with your action plan.
Procedure for Fetal Blood Sampling
(Please note there is no audio for this video.)