OPERATIVE VAGINAL DELIVERY Flashcards
What is operative vaginal delivery (OVD)?
Birth accomplished with assistance from forceps or a vacuum-cup device, using outward traction to augment maternal pushing.
What is the ratio of vacuum to forceps deliveries?
Approximately 4:1.
What are the common maternal indications for OVD?
-Maternal exhaustion
- prolonged second-stage labor
- pulmonary compromise
-infection-related decompensation
- neurological disease
- cardiac disorders.
What are frequent fetal indications for OVD?
- Nonreassuring fetal heart rate
- premature placental separation.
What are the three classifications of OVD based on station?
Outlet, low, and midpelvic.
(mc are outlet and low)
What is the prerequisite for fetal station in low forceps delivery?
Fetal station must be ≥+2 cm but not on the pelvic floor.
What type of regional analgesia is preferred for low or midpelvic OVD?
Regional analgesia is preferred; pudendal blockade may suffice for outlet deliveries.
Why should the maternal bladder be emptied before OVD?
To provide additional pelvic space and minimize bladder trauma.
What is OASIS in the context of OVD complications?
Obstetrical anal sphincter injuries, including third- and fourth-degree perineal lacerations.
Which episiotomy type offers greater protection against OASIS?
Mediolateral episiotomy.
What are common neonatal injuries associated with vacuum extraction during OVD?
- Cephalohematoma
- subgaleal hemorrhage
- retinal hemorrhage
- neonatal jaundice
- scalp lacerations.
What types of injuries are more frequent with forceps delivery?
- Facial nerve injury
- brachial plexus injury
- depressed skull fracture
- corneal abrasion.
What is a proposed mechanism for brachial plexus injury during OVD?
Traction forces causing stretch on the brachial plexus as the fetal head descends while the shoulders remain at the pelvic inlet.
Is long-term neurodevelopmental morbidity associated with OVD?
No, studies show no significant association between OVD and long-term neurodevelopmental issues like epilepsy or cerebral palsy.
When is a trial of OVD recommended?
When the procedure is expected to be difficult, to allow immediate cesarean delivery if it fails.
What are the four components of a forceps branch?
Blade, shank, lock, and handle.
(BS-LH)
BLADE
SHANK
LOCK
HANDLE
What does the cephalic curve of the forceps blade conform to?
The round fetal head.
What is the function of the pelvic curve in forceps design?
It corresponds to the curve of the birth canal.
What is the advantage of fenestrated blades in forceps?
They reduce head slippage during forceps rotation.
What is the disadvantage of fenestrated blades?
Increased blade thickness and friction against the vaginal wall.
What are pseudo-fenestrated forceps blades?
Blades smooth on the outer maternal side but indented on the inner fetal side.
What is the purpose of parallel shanks in forceps?
They limit compression of blades against the fetal head.
What is a disadvantage of parallel shanks?
They add width against the introitus.
What is the benefit of overlapping shanks in forceps?
They raise compression forces but distend the perineum less, making them advantageous for outlet deliveries.
What are the three main types of forceps locks?
(SEP)
SLIDING LOCK
ENGLISH LOCK
PIVOT LOCK
How should forceps blades be applied for an OA fetal head position?
The left blade is inserted into the left posterior vagina first, followed by the right blade on the right side, both guided by fingers.
What should be reassessed if forceps branches fail to articulate?
Blade relationships to the fetal sutures.
How is traction applied during forceps delivery?
Gentle, intermittent, downward and outward traction is exerted with maternal efforts.
GENTLE
INTERMITTENT
DOWNWARD
OUTWARD
What should be done before applying traction with forceps?
Rotate the fetal head to the OA position.
Why is intermittent traction preferred during forceps delivery?
To prevent undue head compression and simulate spontaneous labor.
What is the primary risk of OP position delivery with forceps?
Higher incidence of severe perineal lacerations and Erb/facial nerve palsies.
What is the preferred forceps for rotations from OP to OA positions?
Kielland forceps.
What is the success rate of manual rotation for OP positions?
> 90%, according to studies like those by Le Ray et al.
What are the benefits of manual rotation for OP positions?
Lower cesarean delivery rates, reduced OVD, less perineal trauma, and decreased chorioamnionitis risk.
What technique is used for manual rotation of an ROP fetal head?
The right palm cups the fetal head, rotates clockwise while flexing and destationing the head.
What should be avoided during manual rotation destationing?
Disengaging the fetal head from the maternal pelvis.
What complications are associated with OP forceps delivery?
- Severe perineal trauma
- higher risk of nerve palsies
- extensive episiotomy.
What direction is traction initially applied during low forceps delivery?
Downward, bringing the fetal head beneath the symphysis.
When should forceps blades be removed during delivery?
After the head crowns to reduce vulvar distention and prevent laceration.
How is a fetal head rotated from LOT to OA using Kielland forceps?
The anterior blade is first wandered posteriorly, swept around to an anterior position, and the second blade is inserted posteriorly.
How do overlapping forceps shanks benefit outlet deliveries?
They reduce perineal distention compared to parallel shanks.
What is the advantage of sliding locks in forceps?
They allow adjustment of branch alignment during asynclitism corrections.
Why is ultrasound used during forceps application?
To document and guide fetal head rotation.
What is vacuum-assisted operative vaginal delivery (OVD) commonly referred to in Europe?
Ventouse
What are the theoretical benefits of a vacuum extractor compared to forceps?
Simpler requirements for precise positioning on the fetal head and avoidance of space-occupying blades within the vagina to reduce maternal trauma.
What are the primary components of a vacuum device?
(CS-HV)
Cup, shaft, handle, and vacuum generator.
What are the two main types of vacuum cups?
Soft bell cups and rigid mushroom cups.
Which type of vacuum cup generates significantly more traction force?
Rigid mushroom cups.
Which vacuum cup type is associated with higher scalp laceration rates?
Rigid mushroom cups.
What is the advantage of soft bell cups in vacuum-assisted delivery?
They are associated with a lower incidence of scalp injuries compared to rigid cups.
Why are flexible shafts preferred for OP positions or asynclitism?
They permit better seating of the cup.
What is the correct placement of the vacuum cup on the fetal scalp?
Over the flexion point, 3 cm from the posterior fontanel and 6 cm from the anterior fontanel along the sagittal suture.
What are the benefits of proper cup placement during vacuum-assisted delivery?
Maximizes traction, minimizes cup detachment, flexes the neck, and delivers the smallest head diameter through the pelvic outlet.
What should be avoided during vacuum-assisted delivery traction?
Jerking, rocking, or applying rotational forces to the cup.
What is the recommended maximum negative pressure for creating suction during vacuum-assisted delivery?
0.8 kg/cm².
What is the general guideline for vacuum-assisted delivery regarding traction attempts?
Progressive descent should accompany each traction attempt, and lack of descent warrants alternative delivery approaches.
What is a common reason for cup dislodgement during vacuum-assisted delivery?
Maternal soft tissue entrapment or improper cup placement.
What is the median number of OVD procedures completed by recent trainees in accredited programs?
Approximately 20 procedures.
What is the minimum number of OVD procedures required for residents completing training in 2021?
15 procedures.
How can residency programs improve training in OVD?
Through simulation-based education and having skilled instructors readily available.
What was the result of implementing an OVD simulation curriculum in one study?
22-percent reduction in OASIS rates and a decline in severe maternal and neonatal morbidity.
What is the role of the non-dominant hand during vacuum-assisted delivery pulls?
Placed within the vagina to judge descent, adjust traction angle, and assess cup edge-to-scalp relationship.
What should be done between contractions during vacuum-assisted delivery in some cases?
Lower suction levels to reduce scalp injury rates or maintain suction to aid rapid delivery if there is a nonreassuring fetal heart rate.
