1. Non Obstetric Surgery in
Pregnant Patients
Dr. Sudip Kumar Saha
DA student
Department of
Anaesthesiology
SSMCMH, Dhaka

2. Introduction
 Anaesthesiologist who care for pregnant
patient undergoing non-obstetric surgery
must provide safe anesthesia for both
mother & fetus.
 To maintain maternal safety the
physiological & anatomical changes of
pregnancy must be
considered, anesthetic technique & drug
administration modified accordingly.
 Fetal wellbeing is related to avoidance of
fetal asphyxia & teratogenic drugs &
preterm labour.

3. Goals of an
Anaesthesiologist
 Optimization & maintainance of
normal maternal physiological
function.
 Optimization & maintainance of
uteroplacental blood flow & O2
delivery.
 Avoidance of unwanted drug effects
on the fetus.
 Avoidance of stimulating myometrium.
 Avoidance of awareness during GA.
 Using regional anesthesia , if possible.

4. Incidence
 0.75% to 2% of pregnant women undergo
surgeries
 75,000 – 80,000 procedures annually in USA
 Centralized data unavailable in Bangladesh
 Conditions common to this age group: Ovarian
cysts, appendicitis, cholelithiasis, cervical
incompetence, breast or other
malignancies, traumatic injuries.
 Commonest surgery- Appendicectomy.

5. Incidence
23%
35%
42%
Distribution of surgery according to
trimesters
1st Trimester
2nd
Trimester
Trimester breakdown of nonobstetric surgery undertaken during pregnancy.
Modified from Mazze RI, Kallen B. Am J Obstet Gynecol 1989;161:1178–85.

6. Most common surgical procedures
performed in pregnant women
Type of
surgery
1st trimester 2nd trimester 3rd trimester
C.N.S. 6.7% 5.4% 5.6%
E.N.T. 7.6% 6.4% 9.5%
Abdominal 19.9% 30.1% 22.6%
Genitourinary/
Gynaecological
10.6% 23.3% 24.3%
Laproscopic 34.1% 1.5% 5.6%
Orthopaedics 8.9% 9.3% 13.7%
Endoscopy 3.6% 11% 8.6%
Skin 3.8% 3.2% 4.1%
Adapted from Mazze RL, Kallen B: Reproductive outcome after anaesthesia
and surgery during pregnancy: A registry study of 5,405 cases, Am J Obstet
Gynecol 161:1178-1185, 1989

7. Surgeries in pregnancy
 Directly related to pregnancy -
◦ Eg: Cervical encirclage
 Indirectly related to pregnancy -
◦ Eg: Ovarian Cystectomy
 Not related to pregnancy -
◦ Eg: Appendicectomy, Intestinal
obstruction

8. 4 areas of unique concern
Maternal
Safety
Avoidance
of
intrauterine
asphyxia
Avoidance
of
teratogenic
drugs
Prevention
of preterm
labour

9. PHYSIOLOGICAL &
ANATOMICAL CHANGES
DURING PREGNANCY.
Maternal safety

10. Cardiovascular changes
 CO increase in pregnancy by 50% due to
combined increase in HR(25%) & SV(30%).
 SVR decreased due to oestrogen & progesterone.
 ECG changes occur in pregnancy are entirely
normal include left axis deviation & ST/T changes.
Heart murmur are also common due to turbulence
associated with increased blood flow.
 RCV increase 35-50%.
 Pregnancy is a hypercoagulable state with an
increase in most clotting factor. Platelet count fall
but an increase in platelet consumption occur.
 Pregnancy is a significant risk factor for
thromboembolism.

11. Respiratory & GIT changes:
 Oxygen consumption increases upto
60% at term.
 MV increases early due to an increase in
RR & tidal volume &is up by 45%.
Increased MV is mediated by
progesterone which acts as a respiratory
stimulant. Increased MV causes resp.
alkalosis.
 FRC is decreased in pregnancy.
 Circulating progesterone reduces the
LOS tone, increasing the incidence of
esophageal reflux..

12. Drugs: altered pharmacokinetics/
pharmacodynamics
 The MAC of volatile agents is reduced
by 30% under the influence of
progesterone.
 There is a decrease in plasma
cholinesterase level by 25%.
 The increased blood volume causes
physiological hypoalbuminemia.
 The volume of epidural &
subarachnoid space is reduced due to
the gravid uterus compressing the IVC
causing distension of epidural venous

13. Remember the following
manoeuver
Remembering left lateral tilt to
prevent aortocaval
compression.
Remembering meticulous pre-
oxygenation to prevent hypoxia.
Remembering antacid
prophylaxis & RSI to reduce
risk of aspiration.

14. Anaesthesia Considerations
 First “Rule of Thumb”
 Administer drug to the patient only if benefits
clearly outweigh the risk, both to the mother and
the fetus
 Planning the Anaesthesia Regimen
depends on-
1. Patient‟s present surgical status
2. Present gestational age of the fetus
3. Pregnancy induced physiological changes
4. Other coexisting co-morbidities

15.  Emergencies will always outweigh the concern for the
fetus
„The parturient is the primary
patient‟
The regimen that has been chosen should cater to..
 Needs of the Patient
„Physical and emotional status of the patient dictates the
regimen‟
 Needs of the Operating Surgeon
„Often the anaesthetic regimen that will optimize the
positioning and surgical exposure‟
 Needs of the Obstetrician
„May need a regimen that causes uterine relaxation‟
Anaesthesia Considerations

16. Choice of Anaesthesia
 Both General and Regional anaesthesia
have been used successfully in pregnant
patients.
 No technique has been proven to have
superiority over the other in fetal
outcomes.
 Each technique has its own advantages
and disadvantages and the selection of
technique is based on maternal
condition, site and nature of surgery and

17. Subarachnoid Block
Advantages
 Minimal amount of Local Anaesthetics
 Rapid onset of anaesthesia
 Definitive end point
 Easy to administer
 Dense Blockade
Disadvantages
 Hypotension, sometimes profound
 Non rectifiable dermatomal level
 PDPH
 Limited post op analgesia as compared to epidural
 More incidence of nausea/vomiting

18. Epidural Block
Advantages
 Minimal risk of severe hypotension
 Rectifiable dermatomal level
 Excellent post op analgesia
 Risk of meningitis and PDPH eliminated
 High level of haemodynamic stability
Disadvantages
 Procedure is more complex/skilled
 Onset of action is slower
 Amount of local anaesthetic required is more
 Higher incidence of failure/partial action/sparing
 Less profound block

19. General Anaesthesia
Advantages
 Definitive
 Easy to titrate the depth
 Best uterine relaxation
 Risk of meningitis and PDPH eliminated
 High level of haemodynamic stability
Disadvantages
 Possible teratogenic effect
 Maternal risk of aspiration
 High incidence of post op pain, nausea and
vomiting

20. • Most serious risk during non-obstetric
surgery is intrauterine asphyxia
• Causes of hypoxia: Difficult
intubation, esophageal intubation, pulmonary
aspiration, high levels of regional
block, systemic local anesthetic toxicity or
airway compromise from trauma
• Causes of decreased uteroplacental
perfusion: Aortocaval compression, high level
of spinal or epidural
blockade, hemorrhage, hypovolemia, hyper
ventilation, high dose of ά adrenergic agents
or increased circulating
catecholamines, uterine hypertonus from
ketamine >2mg/kg in early pregnancy or
Effects of anaesthesia on Foetus

21. Intrauterine foetal asphyxia
Avoided by
maintaining the
following variables
of foetal respiration-
• Maternal
oxygenation
• Maternal CO2
tension
• Uterine blood flow

23. Consensus Statement
Approved by American Society of
Anaesthesiologists (ASA) and American College
of Obstetricians and Gynecologists (ACOG) on
Oct 21, 2009
The following generalizations have been made: -
1. No currently used anaesthetic agents have
been shown to have any teratogenic effects in
humans when using standard concentrations at
any gestational age.
2. Fetal heart rate monitoring may assist in
maternal positioning and cardio-respiratory
management, and may influence a decision to
deliver the fetus.

24. Recommendations include..
 It is mandatory to obtain an obstetric
consultation before performing any non
obstetric surgery or any invasive procedures
 A pregnant woman should never be denied
indicated surgery, regardless of trimester.
 Elective surgery should be postponed until after
delivery.
 If possible, non-urgent surgery should be
performed in the second trimester when preterm
contractions and spontaneous abortion are least
likely.

25. Recommendations for foetal
monitoring include..
 Surgery should be done at an institution with neonatal
and pediatric services.
 An obstetric provider with cesarean delivery privileges
should be readily available.
 A qualified individual should be readily available to
interpret the fetal heart rate.
General guidelines for fetal monitoring include –
 In a previable foetus - ascertain the fetal heart rate by
Doppler before and after the procedure.
 In a viable foetus - simultaneous electronic fetal heart
rate and contraction monitoring, before and after the
procedure to assess fetal well-being and the absence of
contractions.
 The fetus is viable, it is advisable to obtain informed
consent to emergency cesarean delivery.

26. When to do the surgery??
 It depends on balance between maternal and
foetal risk urgency of the surgery
1st trimester – Organogenesis
◦ Increased foetal risk for teratogenesis
3rd trimester – Peak of physiological changes
of pregnancy
◦ Increased maternal risk
 Thus 2nd trimester is considered to be a
ideal time for non emergency, mandatory
surgeries

27. When to do the surgery??
Carvalho B, Anesth Analg Suppl IARS

28. Teratogenecity: general
 Fetal risk: 0-15 days- usually
embryotoxic(EGA 2-4 wks)
 15-60 days(organogenesis)- great risk
to fetus.
 Then functional defecit.
 Nearly all drugs have been
demonstrated to be teratogenic in
some species at some dose.

29. Teratogenecity:
BZD/Opioids
 BZD/Minor tranquilizer: Associated
with increased anomalies. BZD
initially associated with increased cleft
palate.
 FDA: Minor tranquilizer should almost
always be avoided in 1st trimester.
 Single dose: no effect.
 Synthetic opioids : Animal studies not
teratogenic.

30. Teratogenecity:
Muscle relaxant & LA
 Muscle relaxant: minimal placental
transfer.
 LA(local anesthetics): no evidence of
problem in human.
 Cocaine: is a known teratogen.
IUGR, preterm delivery, & increased
risk of abruptio placenta.

31. Teratogenecity:
induction agent
 Ketamine: not teratogenic but
>1mg/kg- increased risk of preterm
labour.
 Thiopental Na: not teratogenic in
conventional doses.
 Propofol: no adverse fetal effects
compared to thiopental.
Propofol+Succinylcholine may cause
severe maternal bradycardia.

32. Teratogenecity: N2O
 Theoretical risk is decreased but
reversible DNA synthesis.
 Pretreatment with folinic acid is not
proven effective in preventing
neurogenic teratogenecity in animal.
 Conclusion: teratogenic only under
extreme condition. However slightly
increased abortion risk.

33. Teratogenecity:
inhalational agent
 Volatile anaesthetic: shows
teratogenecity in some species.
 Volatile anaesthetic & N2O in rats
showed no anomaly at any gestational
age.
 Like N2O , slightly increased risk of
abortion.

34. F.D.A classification of risk of
teratatogenicity of drugs (1979)
Category Clinical Implications
Category A Adequate and well controlled studies have failed to demonstrate a
risk to the foetus in the first trimester of pregnancy (and there is no
evidence of risk in later pregnancies)
Category B Animal reproduction studies have failed to demonstrate a foetal risk
but there are no controlled studies in pregnant women, OR animal
reproduction studies have shown an adverse effect, but adequate
well controlled studies in pregnant women have failed to demonstrate
a risk to the foetus in any trimester.
Category C Animal reproduction studies have shown an adverse effect on the
foetus and there are no adequate well controlled studies in humans,
or studies in animals and humans are not available. Potential benefits
of drugs may warrant use of drug in pregnant women despite
potential risks.
Category D There is positive evidence of human foetal risk, but the benefits from
use in pregnant women may be acceptable despite the risk (e.g. life
threatening situation or serious disease for which safer drugs are not
available).
Category X Studies in animals or humans have demonstrated foetal
abnormalities, or evidence based on human experience, and the risk
of use of the drug in pregnant women clearly outweighs any possible
benefit. The drug is contraindicated in women who are or may

35. Documented teratogens
(Adapted: ACOG Educational Bulletin #236, 1997)
ACE inhibitors Lithium
Alcohol Mercury
Androgens Phenytoin
Antithyroid drugs Radiation (>0.5 Gy)
Carbamazepine Streptomycin/kanamycin
Chemotherapy agents Tetracycline
Cocaine Thalidomide
Coumadin Trimethadione
Diethylstilbestrol Valproic acid
Lead Vitamin A derivatives

36. Intra-operative monitoring
BP,HR,RR
ECG
SpO2ETCO2
FHR

37. Special situations - Trauma
 Among the leading causes of maternal
mortality/morbidity
 Maternal life takes precedence over foetal
life.
 Primary management goals (Fluid
resuscitation/Airway management) is similar
to non pregnant females.
 Mother should receive all diagnostic tests
deemed necessary for her optimal
management, shielding the foetus when
possible.
 More prone to pulmonary oedema due to
relative hypoproteinemia & hypervolemia
 Conservative, CVP guided fluid therapy is
recommended

38.  Early USG – Foetal viability, monitoring to continue
 Avoid – Hypoxia, Hypotension, Hypothermia and
Acidosis
 Causes of foetal loss –
◦ Maternal mortality
◦ Abruption
 Indications for emergency Caesarean section in
pregnant trauma patient: -
1. Traumatic uterine rupture
2. Haemodynamically stable mother with foetal distess
3. Gravid uterus that is interfering with intraoperative
surgical repair
Special situations - Trauma

39.  It is no longer considered to be a contraindication to
laparoscopic surgery
 Concerns in Laparoscopic surgeries
Pneumoperitoneum with trendelenberg position
Reduced lung compliance and FRC.
Increased airway pressures
Hypoxia in advanced gestation.
Pneumoperitoneum with reverse trendelenberg position
Significant aorto venacaval compression
Reduced venous return & hypotension.
Pregnancy is a prothrombotic state.
Lower extremity venous stasis due to pneumoperitoneum
- higher risk of thromboembolism
Special situations –
Laparoscopy

40.  Recommendations for Laproscopy
1. Use an open technique to enter the abdomen to
avoid potential uterine or fetal trauma.
2. Monitor maternal end-tidal CO2 (30–35 mmHg
range) arterial blood gas (if the procedure is
prolonged) to avoid fetal hypercarbia and acidosis
3. Maintain low pneumoperitoneum pressures (8–12
mm Hg, not 15 mm Hg)
4. Minimize insufflation time or use a gasless
technique to avoid decreases in uteroplacental
perfusion
5. Protect the uterus with lead shielding during intraop
radiological procedures (Cholangiography)
6. Limit the extent of Trendelenburg and reverse
Trendelenburg positions. Initiate any position
changes slowly. Left lateral tilt is to be maintained.
7. Pneumatic stockings to be used
8. Monitor fetal heart rate and uterine tone when
Special situations –
Laparoscopy

41. Laparoscopic Vs Open
Appendicectomy
 A study was designed in USA (2007)
have shown that laparoscopic
appendicectomy in pregnancy is
associated with a low rate of intra-
operative complication & less
requirement of postoperative analgesia
in all trimester. However, laparoscopic
appendicectomy is associated with a
significantly higher rate of fetal loss
compared to open appendicectomy.
 Open appendicectomy would appear to
be the safer option for pregnant women
for whom surgical intervention is
indicated.

42.  Aneurysm clipping may be needed during
pregnancy.
 Meningiomas have steroidal receptors, it
increases in size during pregnancy due to
vascular proliferation and increased
intravascular volume.
 Fetal monitoring is necessary when blood
loss, large volume shifts and hypotension is
expected
 Placental circulation has poor autoregulation.
It depends on systemic pressure.
 Reduction in systolic pressures > 20-30% or
MAP<70 mmHg, reduces placental blood
Special situations - Neurosurgery

43.  SNP in doses > 0.5mg/kg/hr can cause
cyanide toxicity in the foetus. NTG is a safer
option.
 Maternal hyperventilation and resultant
hypocarbia (pCO2 < 25mmHg) shifts the
oxyhaemoglobin curve to the right and
hampers fetal oxygenation.
 Osmotic diuresis can lead to fetal
dehydration.
 Endovascular procedures abolish the need
for craniotomy. Fetal shielding during the
procedure is necessary
Special situations - Neurosurgery

44. Postoperative care:
 Pregnancy is a hyper-coagulable state
& the risk of thromboembolic is further
increased by postoperative venous
stasis.
 Early mobilization
 Maintaining adequate hydration
 Pneumatic stocking gloves
 Pharmacological prophylaxis

45. Post op analgesia:
 Adequate analgesia is important as pain
will cause increased circulating
catecholamines which impair
uteroplacental perfusion.
 Analgesia may mask the signs of early
preterm labour.
 Paracetamol & Diclofenac is pregnancy
risk category B.
 Ibuprofen, Morphine, Tramadol is
pregnancy risk category C.
 NSAIDS can cause early closure of
ductus arteriosus in 3rd trimester.

46. Outcome
Cohen, Kerem et all, American Journal of Surgery in 2005
conducted a literature review of 54 studies in England over
last 10 years
Statistics
 Total patients reviewed – 12,452
 Maternal deaths – 0.006%
 Miscarriage – 5.8%
 Elective termination of pregnancy – 1.3%
 Preterm labor induced by surgery – 3.5%
 Foetal loss – 2.5%
 Prematurity – 8.2%
 Major birth defects (1st trimester surgeries) – 3.9%
R. Cohen-Kerem et al. / The American Journal of Surgery 190

47. Outcome
Conclusions: -
 Using modern surgical and anesthetic techniques, the risk of
maternal death appears to be very low.
 Surgery and general anesthesia do not appear to be major
risk factors for spontaneous abortion.
 The rate of elective termination appears to be in the range
of the general population.
 Non-obstetric surgical procedures do not increase the risk for
major birth defects. Hence, urgent surgical procedures
should be performed when needed.
 Acute appendicitis, especially when accompanied by
peritonitis, appears to be genuine risk for surgery induced
labor or fetal loss.
R. Cohen-Kerem et al. / The American Journal of Surgery 190

48. Conclusion:
Remembering the physiological
& anatomical changes of
pregnancy.
Prevention of foetal asphyxia
by maintaining maternal
oxygenation, ventilation&
haemodynamic stability.
Remembering postoperative
thromboprophylaxis.

49. “ A baby is something you carry inside you for nine months, in your
arms for three years and in your heart till the day you die…”
-- Mary Mason