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

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

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.

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

麻醉紀錄

Non-obstetric Surgery during Pregnancy Discussion : Non-obstetric Surgery during Pregnancy

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

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

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.

Physiologic Changes

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.

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.

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.

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)

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.

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)

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

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