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Physiology of labor. Anaesthesia in laborPresentation Transcript
Physiology of labor.
Anesthesia in labor
LABOR–is the physiology process whereby
regular uterine activity causes progressive
cervical dilatation and usually results in
delivery of the fetus, after 22 weeks of
- Labor is a physiologic process that
permits a series of extensive physiologic
changes in the mother to allow for the
delivery of her fetus through the birth
- It is defined as progressive cervical
effacement, dilatation, or both, resulting
from regular uterine contractions that occur
at least every 5 minutes and last 30-60
Classification of labor
PRETERM LABOR– delivery the fetus from
the cavity of uterus in 22-36 weeks of
TERM LABOR- delivery the fetus from the
cavity of uterus in 37-42 weeks of
Delayed labor- delivery the fetus from the
cavity of uterus after 42 weeks of
Theories, which explain the
mechanism of birth
Forerunners of labor
The bottom of uterus is lowering
Insertion of pre-lying part
Krestellers cork is going away.
Reductions of woman’s weight.
Irregular muscular contractions of
Maturity of uterus’s cervix
Softened, but thick in
the area of internal os
effacement of cervix
More than 2 сm
Less than 1 cm or
cervical canal or
External os is closed
or lets pass trough
Cervical canal lets pass
one finger freely.
Internal os is still
Cervical canal lets
pass more than
one finger freely. If
the cervix is
effaced – dilatation
more than 2 cm
Disposition of the
0-2 points – uterus’ cervix is “immature”
3-4 points – cervix is “mature but not enough”
5-8 points – cervix is “mature”
Cervical effacement in
Cervical dilataton in
1. Irregular uterine contractions.
2. There are no structure changes in the
cervix of uterus.
3. Duration 6-8 hours
Labor begins with
Regular muscular contractions.
Forming of amniotic vial.
І stage (cervical) – dilatation of the cervix
ІІ stage (pelvic) – starts from complete
dilatation of cervix to the delivery of baby
ІІІ stage (placental)- starts from the birth
of baby till delivery of the placenta. (5-30
The first period of labor
Uterine contractions – regular
contractions of uteri musculature.
Typically, contractions occur every 5-10
minutes and last for 20-25 seconds in the
onset of labor.
As labor progresses, the contractions
become more frequent, more intense,
and last longer.
Characteristics of uterine
Tonus – minimal pressure between contractions –
10-12 mm Hg.
Intensivity – difference between amplitude and
basal tonus of uterus 30-50-70 mm Hg.
Frequency per 10 min – 3-4 за 10 хв.
Duration – 35 - 93 сек.
Rhythm - intervals between contractions – equal.
Activity = intensivity х frequency per 10 min = 280340 Montevideo units
The second stage of labor
Is the periodic contractions of diaphragm,
pelvic floor muscles and front abdominal
which are add to the force of uterine
The birth canal
Record methods of labor
Tocography (external and inernal)
А – dynamic of cervical effacement
Б – advancement of the presenting part of fetus
Fetal blood sampling
Types of placenta separation
Methods of obtainment of the
separated placenta (afterbirth)
Method of Abuladze
Examination of placenta and
Manual separation of
Anesthesia in Labor
Causes of labor pain:
- Hypoxia of uterine muscle
- Stretching of the uterus’ lower
- Stretching of the uterus’ ligaments
- Psychological causes
Modern methods of the pain relief:
Psychological training of
-Decreases phychological component
-Decreases fear of labor
-Forms correct imagination about
labor in patient
1 lesson– anatomy and physiology, changes
2 lesson– 1st period of labor, correct
behaviour of patient, role of partner;
3 lesson– 2nd and 3rd periods of labor;
4 lesson – port-partum period, breast
feeding, caring of baby;
5th lesson - revision.
Medicamental pain relief must have
Simplicity of usage
Safety for mother and fetus!
Indications to Anesthesia:
No effect from the psychoprophylaxis;
Gestoses of the second half of pregnancy
Hard extragenital patology
Operative interferences ;
Promedol 1% - 1 ml
Sibasone 0,5% - 2 ml
Anatomical abnormalities, such as spina bifida or scoliosis
Previous spinal surgery (where scar tissue may hamper the
spread of medication, or may cause an acquired tethered spinal
Certain problems of the central nervous system, including multiple
sclerosis or syringomyelia
Certain heart-valve problems (such as aortic stenosis, where the
vasodilation induced by the anaesthetic may impair blood supply
to the thickened heart muscle.)
Bleeding disorder (coagulopathy) or anticoagulant medication (e.g.
warfarin) - risk of spinal cord-compressing hematoma Infection
near the point of intended insertion Infection in the bloodstream
which may "seed" via the catheter into the (otherwise relatively
impervious) central nervous system
Uncorrected hypovolemia (low circulating blood volume)
(episiotomy, reparation of
Lidocain2% 4-10 ml is used