MINISTRY OF MINISTRY OF HEALTH
EDUCATION AND TRAINING
HANOI MEDICAL UNIVERSITY
STUDY ON THE HEMODYNAMIC EFECTS OF
PHENYLEPHRINE IN THE MANAGEMENT OF
HYPOTENSION DURING SPINAL ANESTHESIA
FOR CESAREAN SECTION
Specialized in : Anesthesiology
Code : 62 72 01 21
MEDICAL DOCTORAL THESIS SUMMARY
HA NOI - 2019
WORKS ARE COMPLETED AT HANOI MEDICAL UNIVERSITY
Science instructor:
Professor NGUYEN Quoc Kinh
The thesis will be presented in School thesis council
At … h00, day ……. month …..year 2019
The thesis can be found at:
- National library
- Library of Hanoi Medical University
ABBREVIATIONS
BMI : Body Mask Index
CO : Cardiac Output
CI : Cardiac Index
ECG : Electrocardiogram
GTTS : Spinal anesthesia – SA
HA : Blood pressure – BP
HATT : Systolic arterial blood pressure – SBP – SAP
HATTr : Diastolic arterial blood pressure – DBP, DAP
HATB : Mean blood pressure – MAP
HR : Heart Rate
ICG : Impedance Cardiogram
NMC : Epidural anesthesia
Niccomo : Non Invasive Continuous Cardiac Output Monitoring
SpO2 : Saturation of oxygenation
SV : Stroke Volume
SVV : Stroke Volume Veriation
SVR : Systemic Vascular Resistance
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INTRODUCTIONS
Anesthesia in obstetrics for cesarean section increased due to the increasing the
rate of cesarean section, which is a great concern of the anesthesiology because of the
achievement of analgesic effect, good muscle relaxation to maximum facilitate the
operation, ensuring safety for both mother and infant. Spinal anesthesia is preferred
to anesthesia, is the first choice for cesarean section, hypotension when the Spinal
anesthesia accounts for as high as 70% -80%. It is the most dangerous complication,
causing bad consequences for mothers and children. Therefore, the problem of
managing hypotension is always concerned and studied.
The mechanism of hypotension in the spinal anesthesia (SA) is due to blockade of
the sympathetic ganglion, leading to dilatation of the arterial system (resistance system),
which reduces SVR and veinous dilatation (storage system) reduces venous return in a
reduction of the preload and a decrease CO. The blood pressurs (BP) is directly
proportional to CO and SVR. Thus hypotension can be due to decreased SVR and / or
decreased CO. But reducing SVR also reduces afterload so it can improve CO.
There have been studies on infusions around the world (comparing preload
with coload, crystalloid and colloid fluids). Compare phenylephrine effect with
ephedrine on the mother and children. At present, there are no or less invasive
hemodynamic monitoring methods such as CNAP, Clearsight, Niccomo, USCOM…
So in the world there are only a few studies on hemodynamic changes in SA. There
have been no studies to assess the hemodynamic changes of pregnant women,
umbilical cord blood gas in during the cesarean, of phenylephrine and ephedrine in
particular when used to treat hypotension. Therefore, this topic is conducted with the
two following objectives:
1. Compare the effects of phenylephrine with ephedrine on hemodynamic
measured by the non-invasive method Niccomo in the management of the hypotension
during SA for cesarean section.
2. To evaluate some undesirable effects of phenylephrine and ephedrine on
mother and newborn during SA for cesarean section.
*New contributions of the thesis:
1. Scientific and practical meanings:
- The research is very necessary, to be new, especially when applying noninvasive
hemodynamic monitoring method (Niccomo monitoring), the thesis has scientific and
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practical significance. Proper, scientific and logical research design; The datas and the datas
processing are reliable, the number of patients are large enough.
- Ever, the main drug used is ephedrine to treat hypotension in the spinal anesthesia.
However, the ephedrin is suspected of causing fetal acidosis in recent years. Therefore,
foreign and domestic authors have come to phenylephrine to replace ephedrin.
- The authors only researched and used the phenylephrine to increase blood pressure.
No authors studied hemodynamic changes (BP, CO, SV, SVR, HR) by phenylephrine. This
is the new point, the contribution of the topic to clinical practice and science.
2. The thesis has scientific significance, is up to date and very valuable in
clinical gynaeco-obstertrical anesthesia:
- The thesis compares the efficacy of the new vasoconstrictor that is
phenylephrine versus the previously used vasoconstrictor, ephedrine, both of which
are infused continuously to prevent the hypotension in the spinal anesthesia for
cesarean section.
- This study used a new hemodynamic monitoring method that is Niccomo
system to continuously monitor hemodynamic indicators: heart rate, arterial blood
pressure, cardiac output, stroke volume and the systemic vascular resistance. This
hemodynamic monitoring method helps to accurately assess the effectiveness of the
two vasoconstrictor drugs above and helps to guide the fluid infusion to manage
hypotension during spinal anesthesia for cesarean section.
*Layout of the thesis: The thesis consists of 113 pages (excluding references and
appendices) of which: Introduction: 02 pages; Chapter 1 - Overview: 32 pages; Chapter 2
- Objects and Methods: 16 pages; Chapter 3 - Results: 27 pages; Chapter 4 - Discussion:
34 pages; Conclusion: 2 pages. The thesis has 38 tables; 12 photos; 10 charts; 124
references (25 documents in Vietnamese and 99 documents in foreign languages).
CHAPTER 1 - OVERVIEW
1.1. Physiological and anatomial changes in pregnant women are related to
anesthesia: During pregnancy, there are many changes in the circulation and
cardiovascular. Total blood volume increased to 35%, plasma volume increased to
45%, hemoglobin decreased by 15% compared to normal, HR increased by 15%
compared to the original, the SV increased by 30%, but SVR 15% off.
CO increased by 30% to 40% in the first trimester, the months after, it
increased less. During labor, CO increases due to increased HR and SV. Each
contraction of the uterus increases CO and maternal circulation by 10-25%. The