Non-obstetric surgery during pregnancy

Anaesthesia for non-obstetric surgery during pregnancy
Dr.Sathish Krishnan
YG

Introduction
1-2% of pregnant women undergo anaesthesia during their pregnancy for surgery unrelated to delivery
M.C – Appendicitis,ovarian cyst,trauma.
Physiological and pharmacological changes important.

Goals
Maintain normal maternal physiological function
Maintain uteroplacental flow and O2 delivery.
Avoid unwanted drug effects on the fetus
Avoid oxytocic effects
Avoid awareness during G.A
Use regional when possible

Preanaesthetic assessment
Liase with obst & neonatalogist
U.S –if delivery is imminent
Symptoms of cardiac disease & ECG changes are common in pregnancy.
Radiology- minimise fetal exposure.
Relevant blood tests
Premeds-always include aspiration prophylaxis

Avoid NSAIDS.
Drugs
Teratogenic effects- 15th -56 days of gestation
Studies- no increase in teratogenecity but increase in abortion, growth restriction and LBW
Problems were due to primary disease and surgery and not due to anaesthesia
Benzodiazepines not teratogenic & single dose is safe.

GESTATION
No elective surgery during pregnancy
Only tubal ligation in first 6 weeks after delivery
Emergency surgery-regardless of gestational age
Preserve the life of mother
If possible-surgery delayed until 2nd trimester- reduced abortion & teratogenecity - but no firm evidence.

Nonviable fetus
Same principles as for pregnant patient
Coagulopathy risk- should be corrected

Anaesthesia for conception & 1st trimester
IV sedation for invitro fertilisation, should not interfere with fertilisation & embryo development
Propofol – sedation, regional or G.A.N20 avoided
6-8 weeks-physiological changes occur , supplementary O2, hyperventilation.
Airway management- may be difficult. Nasal airways avoided
Reduced pseudocholinesterase (30%), balanced by increase in Vd.
Aspiration prophylaxis from beginning of 2nd trimester
Lower anaes.requirements.reduced MAC (30%) ,IV drugs in lower doses
Fetus assessed by U.S before & after surgery
Regional whenever possible

2nd Trimester
Aortocaval compression from 20 weeks (may be before)
Lateral displacement of uterus
Risk of intravascular injection
Reduce dose of LA
Hypercoagulable state-prophylaxis

3rd Trimester
C.section before major surgery
Surgery delayed for 48 hrs to allow steroid therapy for fetal lung maturation
Regional for section and then converted to GA if needed
Volatile agents in small doses- to prevent uterine atony
Lactation may be supressed, contraindications for breast feeding are patients on ergot, lithium etc

Fetal monitoring
After 24-26 weeks, FH should be monitored
Difficult in obese or abdominal surgery
Inhalation agents cause decrease in FHR variability
Plan of action if fetal distress diagnosed
Minimal uterine manipulation
No evidence to use prophylactic tocolytics

Anaesthetic technique
No evidence to show that regional is better than GA in terms of outcome
Regional minimises fetal drug exposure, airway management is simpler, blood loss reduced & overall risk is less to both mother & fetus
Risk of regional is hypotension- reduce uterine blood flow
Recent studies show that it is more important to treat the blood pressure than to worry about agent
GA only by well trained anaesthetist

Laparoscopic surgeries
Pregnancy is no longer a contraindication for LAP surgeries
Study in Sweden- 2 million deliveries- favoured lap surgeries than open surgeries
Why? Less exposure of fetus to toxic agents, small incisions, less pain, less analgesic needed, rapid recovery & mobilisation.
C02 pneumoperitoneum - risk of hypoxemia, hypercarbia & hypotension.

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