Transcript The Vacuum Extractor

Vacuum Assisted Vaginal Delivery
Siri L. Kjos, MD
Operative Vaginal Delivery Rates
30
25
Rate (%)
20
15
10
5
0
1970
1972
1974
1976
1978
1980
1982
1984
Year
Hankins GDV Am J Obstet Gynecol 1996;175:275-82
1986
1997
Forceps Delivery
• “The art and science of forceps delivery is
becoming a thing of the past”1
• “The status of forceps in modern obstetrics
is constantly under discussion and scrutiny
within the specialty”2
1. Douglas RB, Stromme WB. Operative Obstetrics, 5th ed. 1988
2. Dennen EH. Dennen’s Forceps Deliveries, 3rd ed. 1989
Decline in Forceps Use
• Medical-legal implications and fear of
litigation
• Reliance on cesarean section as a remedy
for abnormal labor and suspected fetal
jeopardy
• Vacuum perceived by many to be easier to
use and less risky to fetus and mother
• Fewer programs are actively training
residents in the use of forceps
Operative Vaginal Delivery Cycle
 use
 fear of litigation
 bad outcomes
 teaching
 technical skills
Operative Vaginal Delivery Rates
7.00%
6.00%
5.00%
4.00%
Forceps
Vacuum
3.00%
2.00%
1.00%
0.00%
1989
Natl Vital Stat Rep1999;47(18):13
1997
Indications
• Prolonged 2nd stage
– Nullipara: no further progress for 3 hours with
regional anesthesia, or 2 hours without regional
anesthesia
– Multipara: no further progress for 2 hours with
regional anesthesia or 1 hour without regional
anesthesia
• Suspicion of immediate or potential fetal
compromise
• Shortening of the 2nd stage for maternal benefit
Prerequisites for Vacuum
Assisted Vaginal Delivery
•
•
•
•
•
•
•
•
•
Complete cervical dilatation
Ruptured membranes
Vertex presentation
Head engaged with position known
Empty bladder
No fetopelvic disproportion
Adequate analgesia
Cesarean section capability
Experienced operator
ACOG OVD Classification (1988)
• Outlet
–
–
–
–
–
scalp visible at introitus without separating labia
fetal skull has reached pelvic floor
sagittal suture in AP diameter or right or left OA or OP
fetal head at or on perineum
rotation < 45o
• Low
– leading point of fetal skull at station > + 2 cm
– rotation < 45o
– rotation > 45o
• Mid - station above +2 cm but head engaged
Vacuum - General Principles
• Allows external traction force applied to the
scalp to be transmitted to the fetal head
• Traction on the vacuum apparatus allows
increased forces of delivery, and facilitates
passage of fetus through pelvis
• Both traction on scalp and compression of
fetal head occur
Metal Cups
Plastic Cups
Components of the Kiwi Omni-Cup
Components of the Kiwi Omni-Cup
Location of the Median Flexion Point:
Where to place the Cup
Occiput Posterior Placement and Lateral Displacement
Contraindications
•
•
•
•
•
•
•
Face presentation
Breech presentation
True cephalopelvic disproportion
Undilated cervix
Congenital anomalies of cranium
Unengaged fetal head
Gestational age < 34 weeks
Application
• Assemble vacuum extractor system and
ensure no leaks are present
• Adequate anesthesia - local perineal
infiltration versus pudendal block
• Insertion of cup into vagina by directing
pressure toward posterior vagina
• Place cup on scalp toward occiput over the
median flexion point
Three Checks
1. No maternal tissue included under cup
margin
2. Cup covers fetal occiput in the midline
3. Marker or vacuum port of suction cup
points towards occiput
Technique
• Initial suction: 10 cm Hg (yellow area).
Reexamine cup edges
•  pressure to 38-58 cm Hg (green area) at
beginning of uterine contraction
• Apply traction along pelvic axis as mother
pushes
• Release pressure to lower level in between
contractions (not necessary with Kiwi)
• As vertex delivers, cup should assume 90o
orientation to horizontal as head extends
Advantages of Vacuum over
Forceps
•
•
•
•
•
•
Easier to apply
Less force applied to fetal head
Less anesthesia needed
No increase in diameter of fetal head
Reduces maternal injury
Reduces fetal scalp injury
Disadvantages of Vacuum over
Forceps
• Cup may detach during procedure
• Used only for term, or near-term vertex
presentations
• Possibly longer delivery as traction is
applied only during contractions
• Possibly associated with more fetal head
trauma
Maternal Complications
Vacuum vs. Forceps
P
Cervical lacerations
Vacuum
Forceps
(n = 256) (n = 300)
10 (3.9%) 18 (6%)
Vaginal lacerations
27 (10.5%) 71 (23.7%) <.001
rd
3 -degree lacerations 41 (16%)
69 (23%)
th
NS
<.03
4 -degree lacerations 48 (18.7%) 70 (23.3%) NS
Broekhuizen FF Obstet Gynecol 1987;69:338-42
Perinatal Complications
Vacuum vs. Forceps
Vacuum
(n = 256)
Cephalohematoma 10 (3.9%)
P
Forceps
( n = 300)
13 (4.3%) NS
Neonatal jaundice 73 (29%)
51 (17%)
<.01
Skin abrasions
89 (30%)
<.001
113 (44%)
Subconjunctival 4 (1.5%)
hemorrhage
Shoulder dystocia 8 (3.1%)
13 (4.3%) NS
1 (0.3%)
<.01
Mortality
1 (0.3%)
NS
1 (0.4%)
Broekhuizen FF Obstet Gynecol 1987;69:338-42
Maternal Complications
Vacuum vs. Forceps
Vacuum Forceps P
(n = 322) (n = 315)
Episiotomy
97
209
<.001
rd
31
67
<.001
th
7
23
.002
Hb difference (g/dl) 1.34
1.46
NS
Estimated blood loss 355.5
347.6
NS
Total time (sec)
244.2
<.001
3 - degree
4 - degree
167.4
Bofill JA Am J Obstet Gynecol 1996;175:1325-30
Neonatal Complications
Vacuum vs. Forceps
Cord arterial pH
Vacuum Forceps P
(n = 322) (n = 315)
7.26
7.25
NS
Shoulder dystocia
15
6
0.052
Scalp trauma
5
8
NS
Cephalohematoma
37
19
.015
Hyperbilirubinemia
24
18
NS
121
<.001
Caput/Molding (day 2) 177
Bofill JA Am J Obstet Gynecol 1996;175:1325-30
Effect of Delivery on Neonatal Injury
Delivery Method
Death
Intracranial
Other*
Hemorrhage
Spontaneous vaginal
1/5000
1/1900
1/216
C/S during labor
1/1250
1/952
1/71
C/S after OVD
N/R
1/333
1/38
C/S without labor
1/1250
1/2040
1/105
Vacuum alone
1/3333
1/860
1/122
Forceps alone
1/2000
1/664
1/76
Vacuum and forceps
1/1666
1/280
1/58
*Facial nerve/brachial plexus injury, convulsions,
CNS depression, mechanical ventilation
Towner, D N Engl J Med 1999;341:1709-1714
Shoulder Dystocia and Time to
Delivery with Operative
Vaginal Delivery
35
Percentage
30
8/24
25
20
15
10
5
8/123
5/490
0
< 3500 g
3500 - 4000 g
Birth weight
Bofill JA J. Matern.-Fetal Med.1997;6:220-4
> 4000 g
Neonatal Complications
• Superficial scalp markings - benign
• Cephalohematoma:
(6%)
– bleeding beneath periosteum
• Subgaleal hematoma:
(50/10,000)
– bleeding in loose subaponeurotic tissues of scalp
• Intracranial hemorrhage: (0.35%)
• Retinal hemorrhage:
(28% - 56%)
Vacuum & Subgaleal Hematomas
No.
%
Spontaneous
35
28.4
Forceps
17
13.8
Vacuum extraction
60
48.8
Cesarean section
11
8.9
TOTAL
123
100
Plauche WC JAMA 1980;244;1597-8
FDA Public Health Advisory
VAVD: May 21, 1998
• Purpose
– to advise that vacuum assisted delivery devices
may cause serious or fatal complications
• Background
– 12 deaths, 9 serious injuries reported during prior
4 years in newborns delivered by VAVD
(average of 5 events/year)
•  5x’s rate c.f that reported in preceding 11 years
Recommendations
– Use only when specific obstetric indication is
present
– Persons should be experienced and aware of
indications, contraindications, & precautions
– Read and understand device’s instructions
– Alert those who will be responsible for care of
neonate that a vacuum has been used
– Educate neonatal care staff about complications
of vacuum
– Report adverse reactions to FDA
Safety Guidelines
• Pull only with maternal pushing
• Never apply torsion to rotation
• Time procedure from moment of application
of cup until delivery of infant
• Duration of time from:
– cup application to delivery: < 20 minutes
– total traction (at max pressure): < 10 minutes
• Abandon after 2 (max 3) “pop offs”
• Abandon if no fetal descent
Documentation
• Indication for procedure, patient consent
• Fetal station & head position at time of
vacuum application(s)
• Type of vacuum device
• Total vacuum application time
• Number of applications and “pop-offs”
• Failure/subsequent mode of delivery
• Delivery data as usual
Factors Influencing Effective
Vacuum Extraction
•
•
•
•
Cup design, shape, size, & application site
Consistency & strength of vacuum
Maternal cervical dilatation
Strength of maternal expulsive efforts &
coordination with traction
• Fetal size & extent of CPD
• Station & deflection of fetal head
• Angle & technique of traction
ACOG Committee Opinion
Number 208, September 1998
• Represents an extraordinarily low risk of
adverse event
• Concern over possible increase in cesarean
section rate if there is decrease in vacuumassisted vaginal deliveries
• Strongly recommends continued use of
vacuum-assisted delivery devices in
appropriate clinical settings
Conclusions
• Vacuum delivery has been proven to be
useful in assisting with vaginal delivery
• The potential for both fetal and maternal
injury does exist
• The operator must be familiar with the
indications, contraindications, application,
and use of the vacuum device
• Safe & effective guidelines should exist to
facilitate a safe and effective delivery
How to determine Distance from Fourchette to
Median Flexion Point
OmniCup
OmniCup
OmniCup
ProCup
ProCup
Time to Delivery with
Operative Vaginal Delivery
8
6/76
7
Percentage
6
5
12/304
4
3
2
1/195
1
0
< 2 min
2 - 6 min
> 6 min
Time required to complete delivery
Bofill JA J.Matern.-Fetal Med 1997;6:220-4
Vacuum Cycle
 use
 fear of litigation
 bad outcomes
 teaching
 technical skills
Types of Complications
– Subgaleal hematoma - accumulation of blood in
potential space between galea aponeurotica and
periosteum of skull
• possibility of life-threatening hemorrhage
– Intracranial hemorrhage
• can include subdural, subarachnoid, intraventricular,
and/or intraparenchymal hemorrhage