How are vasopressors used in spinal anesthesia for cesarean section?

Today the rate of cesarean section is increasing compared to vaginal delivery, anesthetic methods are used to reduce pain for the mother during surgery. Spinal anesthesia for cesarean section is one of the methods chosen by many doctors as well as patients, because of its advantages over other methods of anesthesia.
The quality of spinal anesthesia is quite good compared to other types of anesthesia or anaesthesia, the time from injection to surgery is quick, there is no long wait, the dose used is less than epidural Therefore, the cost of performing spinal anesthesia is also less than epidural anesthesia.
The technique of performing spinal anesthesia is also simpler than other types of anesthesia, general anesthesia and the ability to block movement as well as block sensation is very effective.
However, not everyone is assigned to use spinal anesthesia, cases of absolute contraindications in spinal anesthesia for cesarean section include:
Pregnant women refuse to use this method Emergency cesarean section in cases of placental prolapse, placental abruption or uterine rupture... Caesarean section in emergency cases but not in time to wait for spinal anesthesia to take effect Allergic pregnant women with anesthetics There is inflammation at the area of ​​needle puncture The volume of circulation is not compensated enough, the patient is in shock Pregnant woman has eclampsia The platelet count is less than 50,000/nL Stopping anticoagulants for not enough time and constricted mitral stenosis, constricted aortic stenosis Increased intracranial pressure . The risk of bleeding during surgery In spinal anesthesia for cesarean section, especially when the surgery is in progress, hypotension is the most common side effect, accounting for 70% of the total surgeries. using spinal anesthesia.
To prevent this from happening, methods to prevent hypotension will be used such as intravenous fluids before surgery, adjusting the position of the pregnant woman, using vasopressors...

Vasopressors are used for the purpose of restoring perfusion and enhancing oxygen distribution in patients in shock, treating hypotension during spinal anesthesia for caesarean section... Some vasopressor drugs used as Phenylephrine, Norepinephrine, Epinephrine...
General principles of vasopressor use include:
Vasopressors are used only when circulating volume has been sufficiently compensated while blood pressure is still not The indications for vasopressor therapy have been improved. Indication for vasopressor therapy is improved after the investigation and assessment of blood parameters, assessing whether the patient has any type of hemodynamic disorder to choose the appropriate vasopressor drug. When using the drug, it is necessary to start from a low dose and gradually increase the drug according to the response of blood pressure. Always observe the patient's condition to adjust accordingly in the state of ineffective use of the drug During use The dose of vasopressors should not be adjusted suddenly, if the dose is to be reduced, it must be reduced gradually until the low dose is cut off.

For spinal anesthesia in general and spinal anesthesia for cesarean section in particular, the rate of hypotension is quite high because the main cause is inhibition of the sympathetic system leading to peripheral vasodilation that causes cardiac output to decrease. decrease and lack of relative circulating mass.
In addition, for pregnant women, vena cava compression is more likely to cause hypotension if spinal anesthesia is used during cesarean section.
To prevent and treat hypotension, the doctor will prescribe vasopressors before or during anesthesia.
In the past, phenylephrine was often indicated for use because of its rapid effect, but some unwanted effects of this drug on pregnant women should now be gradually replaced by norepinephrine due to less heart block. than. However, this drug also needs to be studied further to ensure optimal results.
In addition to the above vasopressors, ondansetron is also a vasopressor drug used after spinal anesthesia, the side effects of this drug are almost no. The vasoconstrictor ephedrine 30-60mg is also a way to prevent hypotension in spinal anesthesia for cesarean section, this drug is usually indicated before or during anesthesia.
Accordingly, in order to ensure safety, as well as avoid side effects during spinal anesthesia for cesarean section, patients should choose large medical facilities with specialized anesthesiology and qualified staff. good doctors, can handle quickly and promptly in emergency cases.
Vinmec International General Hospital is one of the hospitals that strictly applies safe surgical anesthesia practice standards according to international guidelines. With a team of experienced anesthesiologists and nurses, along with modern equipment such as nerve detectors, ultrasound machines, Karl Storz difficult airway control system, anesthesia monitoring system GE's comprehensive AoA (Adequate of Anesthesia) including monitoring of anesthesia, pain and muscle relaxation will deliver high quality and safety, helping patients to have adequate anesthesia, not awake, no residual relaxant muscle after surgery. Vinmec Health System is also proud to be the first hospital in Vietnam to sign with the World Anesthesiology Association (WFSA) towards the goal of becoming the safest hospital for surgical anesthesia in Southeast Asia.