Sudip presentation
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Non Obstetric Surgery in Pregnant Patients discusses considerations for anesthesia when performing non-obstetric surgery on pregnant patients. Anesthesiologists must provide safe anesthesia for both the mother and fetus by considering the physiological changes of pregnancy and avoiding fetal asphyxia, teratogenic drugs, and preterm labor. Regional anesthesia techniques like spinal or epidural blocks are preferred when possible due to advantages like limited drug exposure to the fetus. Surgery should generally be performed in the second trimester to balance maternal and fetal risks. Fetal monitoring is recommended during procedures to assess fetal well-being.
Sudip presentation
- 1. Non Obstetric Surgery in Pregnant Patients Dr. Sudip Kumar Saha DA student Department of Anaesthesiology SSMCMH, Dhaka
- 2. Introduction ď‚— Anaesthesiologist who care for pregnant patient undergoing non-obstetric surgery must provide safe anesthesia for both mother & fetus. ď‚— To maintain maternal safety the physiological & anatomical changes of pregnancy must be considered, anesthetic technique & drug administration modified accordingly. ď‚— Fetal wellbeing is related to avoidance of fetal asphyxia & teratogenic drugs & preterm labour.
- 3. Goals of an Anaesthesiologist ď‚— Optimization & maintainance of normal maternal physiological function. ď‚— Optimization & maintainance of uteroplacental blood flow & O2 delivery. ď‚— Avoidance of unwanted drug effects on the fetus. ď‚— Avoidance of stimulating myometrium. ď‚— Avoidance of awareness during GA. ď‚— 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 ď‚— Directly related to pregnancy - â—¦ Eg: Cervical encirclage ď‚— Indirectly related to pregnancy - â—¦ Eg: Ovarian Cystectomy ď‚— Not related to pregnancy - â—¦ 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 ď‚— CO increase in pregnancy by 50% due to combined increase in HR(25%) & SV(30%). ď‚— SVR decreased due to oestrogen & progesterone. ď‚— 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. ď‚— RCV increase 35-50%. ď‚— Pregnancy is a hypercoagulable state with an increase in most clotting factor. Platelet count fall but an increase in platelet consumption occur. ď‚— Pregnancy is a significant risk factor for thromboembolism.
- 11. Respiratory & GIT changes: ď‚— Oxygen consumption increases upto 60% at term. ď‚— 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. ď‚— FRC is decreased in pregnancy. ď‚— Circulating progesterone reduces the LOS tone, increasing the incidence of esophageal reflux..
- 12. Drugs: altered pharmacokinetics/ pharmacodynamics ď‚— The MAC of volatile agents is reduced by 30% under the influence of progesterone. ď‚— There is a decrease in plasma cholinesterase level by 25%. ď‚— The increased blood volume causes physiological hypoalbuminemia. ď‚— 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 ď‚— Both General and Regional anaesthesia have been used successfully in pregnant patients. ď‚— No technique has been proven to have superiority over the other in fetal outcomes. ď‚— 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 ď‚— Minimal amount of Local Anaesthetics ď‚— Rapid onset of anaesthesia ď‚— Definitive end point ď‚— Easy to administer ď‚— Dense Blockade Disadvantages ď‚— Hypotension, sometimes profound ď‚— Non rectifiable dermatomal level ď‚— PDPH ď‚— Limited post op analgesia as compared to epidural ď‚— More incidence of nausea/vomiting
- 18. Epidural Block Advantages ď‚— Minimal risk of severe hypotension ď‚— Rectifiable dermatomal level ď‚— Excellent post op analgesia ď‚— Risk of meningitis and PDPH eliminated ď‚— High level of haemodynamic stability Disadvantages ď‚— Procedure is more complex/skilled ď‚— Onset of action is slower ď‚— Amount of local anaesthetic required is more ď‚— Higher incidence of failure/partial action/sparing ď‚— Less profound block
- 19. General Anaesthesia Advantages ď‚— Definitive ď‚— Easy to titrate the depth ď‚— Best uterine relaxation ď‚— Risk of meningitis and PDPH eliminated ď‚— High level of haemodynamic stability Disadvantages ď‚— Possible teratogenic effect ď‚— Maternal risk of aspiration ď‚— 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.. ď‚— It is mandatory to obtain an obstetric consultation before performing any non obstetric surgery or any invasive procedures ď‚— A pregnant woman should never be denied indicated surgery, regardless of trimester. ď‚— Elective surgery should be postponed until after delivery. ď‚— 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 ď‚— Fetal risk: 0-15 days- usually embryotoxic(EGA 2-4 wks) ď‚— 15-60 days(organogenesis)- great risk to fetus. ď‚— Then functional defecit. ď‚— Nearly all drugs have been demonstrated to be teratogenic in some species at some dose.
- 29. Teratogenecity: BZD/Opioids ď‚— BZD/Minor tranquilizer: Associated with increased anomalies. BZD initially associated with increased cleft palate. ď‚— FDA: Minor tranquilizer should almost always be avoided in 1st trimester. ď‚— Single dose: no effect. ď‚— Synthetic opioids : Animal studies not teratogenic.
- 30. Teratogenecity: Muscle relaxant & LA ď‚— Muscle relaxant: minimal placental transfer. ď‚— LA(local anesthetics): no evidence of problem in human. ď‚— Cocaine: is a known teratogen. IUGR, preterm delivery, & increased risk of abruptio placenta.
- 31. Teratogenecity: induction agent ď‚— Ketamine: not teratogenic but >1mg/kg- increased risk of preterm labour. ď‚— Thiopental Na: not teratogenic in conventional doses. ď‚— Propofol: no adverse fetal effects compared to thiopental. Propofol+Succinylcholine may cause severe maternal bradycardia.
- 32. Teratogenecity: N2O ď‚— Theoretical risk is decreased but reversible DNA synthesis. ď‚— Pretreatment with folinic acid is not proven effective in preventing neurogenic teratogenecity in animal. ď‚— Conclusion: teratogenic only under extreme condition. However slightly increased abortion risk.
- 33. Teratogenecity: inhalational agent ď‚— Volatile anaesthetic: shows teratogenecity in some species. ď‚— Volatile anaesthetic & N2O in rats showed no anomaly at any gestational age. ď‚— 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
- 37. Special situations - Trauma ď‚— Among the leading causes of maternal mortality/morbidity ď‚— Maternal life takes precedence over foetal life. ď‚— Primary management goals (Fluid resuscitation/Airway management) is similar to non pregnant females. ď‚— Mother should receive all diagnostic tests deemed necessary for her optimal management, shielding the foetus when possible. ď‚— More prone to pulmonary oedema due to relative hypoproteinemia & hypervolemia ď‚— 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 ď‚— 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. ď‚— Open appendicectomy would appear to be the safer option for pregnant women for whom surgical intervention is indicated.
- 42. ď‚— Aneurysm clipping may be needed during pregnancy. ď‚— Meningiomas have steroidal receptors, it increases in size during pregnancy due to vascular proliferation and increased intravascular volume. ď‚— Fetal monitoring is necessary when blood loss, large volume shifts and hypotension is expected ď‚— Placental circulation has poor autoregulation. It depends on systemic pressure. ď‚— Reduction in systolic pressures > 20-30% or MAP<70 mmHg, reduces placental blood Special situations - Neurosurgery
- 43. ď‚— SNP in doses > 0.5mg/kg/hr can cause cyanide toxicity in the foetus. NTG is a safer option. ď‚— Maternal hyperventilation and resultant hypocarbia (pCO2 < 25mmHg) shifts the oxyhaemoglobin curve to the right and hampers fetal oxygenation. ď‚— Osmotic diuresis can lead to fetal dehydration. ď‚— Endovascular procedures abolish the need for craniotomy. Fetal shielding during the procedure is necessary Special situations - Neurosurgery
- 44. Postoperative care: ď‚— Pregnancy is a hyper-coagulable state & the risk of thromboembolic is further increased by postoperative venous stasis. ď‚— Early mobilization ď‚— Maintaining adequate hydration ď‚— Pneumatic stocking gloves ď‚— Pharmacological prophylaxis
- 45. Post op analgesia: ď‚— Adequate analgesia is important as pain will cause increased circulating catecholamines which impair uteroplacental perfusion. ď‚— Analgesia may mask the signs of early preterm labour. ď‚— Paracetamol & Diclofenac is pregnancy risk category B. ď‚— Ibuprofen, Morphine, Tramadol is pregnancy risk category C. ď‚— 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: - ď‚— Using modern surgical and anesthetic techniques, the risk of maternal death appears to be very low. ď‚— Surgery and general anesthesia do not appear to be major risk factors for spontaneous abortion. ď‚— The rate of elective termination appears to be in the range of the general population. ď‚— Non-obstetric surgical procedures do not increase the risk for major birth defects. Hence, urgent surgical procedures should be performed when needed. ď‚— 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