Obstetrics suction lecture

2021-03-20 12:00 AM

In the world, there are many different points about the evaluation of the benefits and effects of suction, so the usage situation is also different. North American peppers are rarely used

General perception

Obstetric suction is a popular tool in obstetrics. In 1848 Sampson invented a sensory-type device today based on the principle of using a vacuum force on the fetus to pull the fetus out in cases where the fetus fails. The tool has many disadvantages, which can cause complications for the fetus, so it is not widely used. In 1954 Malmstrom improved the instrument, and has since become more widely used.

The popular international name: vacuum extractor. Currently, there are two commonly used types:

Suction hand pump.

Electric suction pump sensing.

In the world, there are many different points about the evaluation of the benefits and effects of suction, so the usage situation is also different. North American peppers are rarely used because it is thought that the rate of neonatal trauma is very high. In contrast, in Europe, it is widely used, sometimes even overused. In Vietnam, the use of obstetric aspirations is also very popular in some places and very limited in some places.

Although the evaluation of suction is not the same in different countries, all authors acknowledge that this is not a harmless procedure. Accident of intracranial haemorrhage or brain damage can appear immediately or many days after birth by suction. The psychomotor sequelae can be manifested many years later. After Malmström there are two important improvements to simplify usage. Bird changed the structure of the lid and recently replaced it with a soft plastic lid.

Tool description

The electric pump or the hand pump is a closed suction system consisting of two parts:

Vacuum pressure generator

Pump in the opposite direction to suck the air out. A hand pump is like a bicycle pump, while an electric pump uses an electric motor to suck the air out.

Glass bottles with a volume of 650 - 1000ml.

The rubber stopper can adjust the air in or out as desired.

The negative manometer connects to the glass bottle through a rubber stopper. Built-in pressure gauge from 0 - 1 kg / cm2.

Pressure screw to keep negative pressure.

Pulling part

The rubber strap connects the air tank to the chain.

Types of metal caps to capture the fetus with many different sizes: number 4,5 and 6 with diameters of 40, 50 and 60 mm, respectively. The depth of the lid is 15mm.

The chain is 50 - 60cm long, one end has a round metal piece attached to the bottom of the lid, one end is attached to the handle. The chain is threaded in a rubber strap.

The handle is hollow cross-shaped inside, which has a threaded nail through one eye of the chain to help secure when pulling. The handle is connected to the glass by rubber wire.

The effect of smoking sensation

Currently, the only effect of obstetric aspiration is pulled. Thanks to the metal negative pressure, the fetus will spread to the fetus to create a serious tumour on the hard skull base so it is possible to pull the fetus out in the case of women pushing it out. We can calculate the adhesion force by the following formula:

F = P.π.R 2

Where F is the adhesion value in kgF p is the value of the vacuum pressure in the system in kg / cm2.

W = 3.1416.

R is the semi-sparkle of the suction cup in cm.

This adhesion force has a value equal to the value of maximum allowable tensile force in the theory of the same direction but in the opposite direction. When the traction exceeds this value, it will turn the suction cup open.

One point to note is when pulling to pull in a direction perpendicular to the suction cup. If this direction is tilted an alpha angle, the ability to turn on the hood is directly proportional to the magnitude of this angle.


Must be very respectful and master the conditions of suction sensation. It is a key problem of success and leads to less trauma to the fetus: the pelvis and fetus must be proportionate, meaning that the fetus can pass and pass.

The cervix must be completely open.

Mom still has strength.

Pregnant is still alive.

The cusp.

The house is medium or low.

Oh shattered.

Uterine contractions must be good.

Contraindications and contraindications

Designation on the mother's side

Mom presses for a long time not to move.

Mother pushes weak for prolonged labor.

Solid epithelium makes the fetus unable to count.

The mother suffers from mild medical diseases: respiratory, cardiovascular, and toxic during pregnancy.

Indications on the part of the fetus

Pregnancy failure, fetal heart rate over 160 times/minute.

The following types, horizontally do not rotate well. Because suction power over forcefs does not increase the diameter of the number.


To the mother side:

The mother suffers from serious systemic diseases such as heart failure, preeclampsia, eclampsia, high blood pressure.

Threatened uterine rupture.

Old surgical scarring of the uterus.

Abnormal pelvis, mid-waist narrow pelvis, lower waist.

The cervix is ​​not fully opened.

On the fetal side:

Premature pregnancy, malnutrition, poor fetal development in the uterus.

Acute pregnancy failure.

Abnormal pregnancies.

The fetus is not yet born.

Abnormal fetuses, especially hydrocephalus.

Large serous tumour.

Suction technique


Prepare as prepared to forcefs.

To the mother side:

Sanitation: urination, stool enema, vulva disinfection

Chuan is thought of for pregnant women to coordinate with force when pulling the fetus. + Resuscitate the fetus if needed.

On the fetal side:

Here again the fetal heart.

Prepare facilities for resuscitation if needed.


Check all parts of the suction cup and necessary tools to catch the pregnancy.

Physicians and assistants:

Full check-up of pregnant woman, a re-examination of position, pattern, permeability and conditions.

Wash hands, wear gloves, hat and mask.


Then 1: Put the lid

Thumb and index finger ball of the vulva, the right-hand holds the spleen to the vagina and is placed on the base of the fetal bone, so it should avoid the dips and joint lines, ideally placed in the dotted bone.

Choosing the appropriate size of the lid, the lid should be placed as big as possible.

Then 2: Pump and pull

Pump: Slowly aspirate and monitor on manometer until -0.2 kg / cm2 then check again to see if the suction cup is sucked into the uterus, continue to suck until negative pressure reaches -0. , 7-0.8kg / cm2 for a time of 3-5 minutes.

Pulling: pulling perpendicular to the fetus, always keeping the suction cup open, pulling evenly and pulling only with the force of the arm, pulling along the axis of the birth canal, pulling in uterine contractions and combining squeezing of pregnant women.

Then 3: Pull until the crown spleen through the two apical tumours of the vulva, then open

Slowly pressurized the screw to let air into the glass bottle, then slowly remove the suction cup and deliver as normal. After the vegetable book, you need to check again into the vagina, uterus, perineal layer. The newborn examination requires careful examination of the location of the suction cup.


Including catastrophic complications and sequelae, complications for mother and child.

Maternal complications were less than forcefs

Broken uterus and ruptured uterus are rare.

Vaginal and episiotomy tears.

Urinary retention: can be seen from damage to the bladder neck.

The stroke for children is not as heavy as in the case of forcefs

Scalp abrasions and hematomas under the scalp are common. Most cases go away on their own after 3-5 days.

Sub peritoneal haemorrhage is rarer.

Haemorrhage of the brain and meningitis can also be encountered and the frequency of meeting varies depending on the study of each author.

Incidence of complications for children increased significantly in cases of opening the suction cup, excessive negative pressure, or prolonged procedure time.

Advantages and disadvantages of suction cups


No anaesthesia is required.

Respect the physiology of labour (contractions and contractions).

The procedure is simple and gentle.

Widely applicable.

Should respect the conditions and designation is very little accident.


Limited designation.

For mothers: cannot be applied to the mother with disease.

For the fetus: only possible in the case of the crown, in certain cases, it can also cause a lot of damage to the fetus.


Suction cannot be substituted for caesarean section nor for forcefs. Caesarean section, forcefs or suction cups all have their own indications. Many cases of smoking do not have the main indication for the benefit of the mother as well as the child.

It is necessary to fully respect the conditions and indications and contraindications.

Absolutely not because of the easy feeling that we abuse, easily cause many complications for mothers and children.