Abdominal mass in a pregnancy

1. Abdominal mass in a pregnancy -Case presentation By R3陳世昱

2. General & Past History • 35 y/o female • Denied past history of systemic disease or op • No contributable family/drug/allergy history • H: 160cm, W: 54kg • Pregnancy (6wks ; LMP:2003/3/17) with progressive abdominal distention

3. Present Illness (summary 1) • RLQ pain 9 yrs ago • 1998/10, TAS:7x6cm right pelvic mass, suspect endometriosis (which regressed 3 months later spontaneously) • 1999/8, TAS:12x8x8cm heterogeneous mass over uterine fundus and ~30ml ascites; MRI revealed a 1.5cm ROV cyst, and CA-125:WNL • No GI or URO S/S nor ↑CA-125, so OPD f/u was suggested and kept.

4. Present Illness (summary 2) • Missed MC period in 2003/4, and urine pregnancy test showed positive result • Progressive abdominal distension soon later • 4/23 OPD : • TAS: >25x20cm pelvic mass c lacunar pattern and solid component and moderate ascites • ↑CA-125: 578μ/ml • R/O ovarian malignancy → surgical evaluation

6. 麻醉紀錄

8. Non-obstetric Surgery during Pregnancy Discussion :

9. Incidence • About 0.3~2% of deliveries • Most common: appendectomy • Almost every type of surgical procedure

10. Basic objectives • Maternal safety • Avoidance of teratogenic drugs • Avoidance of intrauterine fetal asphyxia • Prevention of preterm labor

11. Monitoring • Routine monitors • Fetal heart rate monitoring: Doppler apparatus such as tocodynamometer(≥umbilicus) after 16wks of pregnancy. • An obstetrician is present throughout operation • Elevations of maternal BP may treat fetal bradycardia, and inhalation agents may diminish the amplitude of uterine contractions.

12. Physiologic Changes

13. Teratogenic drugs(1) • Teratogen: a substance produces an increase in incidence of a particular defect that can’t be attributed to chance. A sufficient dose at a critical point in development is needed. • Critical point in human: during organogenesis, which extends from 15 days’ to approximately 60 days’ gestational age. • CNS does not fully develop until after birth, so critical time for this system could be through the entire gestation.

14. Teratogenic drugs(2) • Almost every anesthetic or drug has been found to be a teratogen in an animal model (in greatly exceeded doses than used clinically), but no anesthetic drug has been documented to be a teratogen in humans. • BZD, Barbiturates, Ketamine, Propofol and Etomidate are known teratogens in animals, but have never been demonstrated in humans. • Narcotics: CNS abnormalities in hamster, but never been reproduced in humans. Low-birth-weight babies has been associated with chronic administration, but no congenital defects.

15. Teratogenic drugs(3) • Muscle relaxants: cause skeletal abnormalities in the chick embryo, but never been reproduced in the human fetus; do NOT cross the placenta • Nitrous oxide: ↓Vit.B12→↓methionine synthetase→↓DNA synthesis, but has been used in hundreds of anesthetics s problems. • Halogenated agents: beneficial to fetus by  uterine relaxation and  increasing uterine blood flow, and so far found it safe in clinical doses.

16. Avoidance of intrauterine fetal asphyxia • Maintain maternal PaO2: • Relative difficult airway • ↓FRC→↑rate of desaturation • Prevent high leveltoxic local anesthetics toxicity andoversedation in regional anesthesia • Adequate maternal PaCO2: • Hypocapnia: • By excessive positive ventilation→↑intrathoracic pressure→↓venous return→↓uterine blood flow • Maternal alkalosis→vasoconstriction & left shift of O2-Hb dis. curve • Hypercapnia: fetal acidosis • Maintain uterine blood flow: • Perfusion pressure: prevent hypotension, aortocaval compression, hemorrhage and “heavy” regional anesthesia • Vasoconstriction: prevent α-agonist, ↓PaCO2 & ↑catecholamines (pain, insufficient anesthesia or so)

17. Prevent of Preterm Labor • The only factors correlated with preterm labor are the type and location of the procedure. • No study documents any correlation of anesthetic drug or technique with preterm labor • However, in theoretically, some anesthetic agents such as ketamine(>1mg/kg) and phenylephrine that can increase uterine tone should be avoid as possible. • The halogenated agents ↓uterine tone &↑uterine blood flow and may be beneficial in this aspect.

18. Recommendations of anesthetizing a pregnancy for Non-obstetric Surgery • Avoid surgery and anesthesia in the first trimester, if possible, without compromising maternal health. • Non-particulate antacid for aspiration pneumonitis prophylaxis after first trimester • Transport patient with left uterine displacement • Continuing fetal/uterus monitoring if possible • Regional anesthesia is recommended whenever possible (fluid preloading; fluid and/or ephedrine)

19. Recommendations of anesthetizing a pregnancy for Non-obstetric Surgery • General anesthesia: • Avoid hypotension with fluid preloading • Airway managements: • Pre-oxygenation with 100%O2 • Induction : rapid-sequence with cricoid-pressure • Maintain adequate oxygenation(50% or higher) and normocarbia • Anesthetic agents: • Drug of Choice: with a long history and relative safety • Pentothal, morphine, fentanyl, meperidine,nitro-oxide • SCC,Atracurium, vecuronium, curare and pancuronium • Halogenated agents may be beneficial • Ketamine and α-agonist should be avoid • Antagonize muscle relaxant and extubate when fully awake and able to control airway reflexs

20. Thanks for Your attention!!