ANESTHESIA FOR NONOBSTETRIC SURGERY IN THE PREGNANT PATIENT

1. ANESTHESIA FOR NONOBSTETRIC SURGERY IN THE PREGNANT PATIENT Vicente Gonzalez CRNA, MS, ARNP 2011 FLORIDA INTERNATIONAL UNIVERSITY PRINCIPLES ANESTHESIOLOGY NURSING II NGR 6422

2. OBJECTIVES • Describe goals of anesthetic management for the pregnant patient having nonobstetric surgery. • Discuss common causes of nonobstetric surgical procedures in the parturient. • Explain significant issues and concerns related to pregnancy and nonobstetric surgical intervention. • Explain clinical anesthetic implications of the physiologic changes related to pregnancy and their effect on organ systems. • Discuss effects of anesthetic agents on the fetus at various stages of gestation. • Formulate an anesthetic care plan for the parturient receiving anesthesia for nonobstetric surgery.

3. REFERENCES • Chestnut, D. H., Polley, L. S., Tsen, L. C., Wong, C. A. (4th Ed.)(2009). Chestnut’s Obstetric Anesthesia, Principles and Practice. Mosby Elsevier ISBN 978-0-323-05541-3. • Nagelhout, J. J., Plaus, K. L. (4th Ed.)(2010). Nurse Anesthesia. Saunders Elsevier. ISBN 978-1-4160-5025-4

4. Incidence • 1.5-2% of all pregnant women will have non-obstetric surgery. • About 80,000/year • Most common surgeries • Appendicitis • Cholelithiasis • Ovarian cysts or torsion • Breast tumors • Trauma

5. Incidence • Appy- 1 in 500 • Chole- 1 in 1600 • A study of appendectomies during C/S increased operative time by 9 minutes. • Out of the 93 total patients 9 had abnormalities.

6. INTRODUCTION • Perioperative care of a pregnant patient for a nonobstetric surgical procedure is a most challenging task faced in clinical practice • Difficulty arises when the surgical procedure must be performed during organogenesis or when fetal viability may be compromised • Such clinical situations are often performed on an emergent basis

7. GOALS IN ANESTHETIC MANAGEMENT • Maternal safety: • Aggressive preoperative preparation and evaluation • Optimum anesthetic management • Adequate analgesia during and after surgery • Full perioperative emotional support • Fetal safety: • Prevention of preterm labor • Avoidance of teratogenic medications • Optimal uteroplacental perfusion

8. COMMON CAUSES OF NONOBSTETRIC SURGERY • Procedures directly related to pregnancy: • Cerclage procedure • Emergency pelvic laparotomy • Procedures incidental to pregnancy: • Surgery for maternal trauma • Acute abdomen • Correction of neurological problem • Correction of decompensating cardiac lesion

9. ISSUES AND CONCERNS • Gestational age is key factor in management of parturients for nonobstetric surgery • Goal of the obstetrician is to preserve the pregnancy until term. Management is directed at prevention of fetal loss • Surgery may be delayed to maximize fetal viability • Implications of the physiologic changes of pregnancy for the conduct of anesthesia and direct effects of anesthetic drugs on the fetus must be realized. Many direct effects on the mother can indirectly affect the fetus

10. CLINICAL ANESTHETIC IMPLICATIONS OF THE PHYSIOLOGIC CHANGES IN PREGNANCY • Respiratory system: • More prone to hypoxia and hypercarbia • Supine position further decreases FRC • Goal is normocarbia • Inhalational induction is more rapid • Consider effects of postoperative pain • Cardiovascular system: • Increased predisposition to thromboembolic problems • Maternal hemodynamics can be altered by enlarging uterus

11. CLINICAL ANESTHETIC IMPLICATIONS OF THE PHYSIOLOGIC CHANGES IN PREGNANCY • Gastrointestinal system: • All parturients must be protected from the risk of regurgitation and aspiration • Antacids and histamine type 2 blockers are indicated • Renal system: • BUN, creatinine, and uric acid levels slightly lower • Central nervous system: • Dose-response relationship to volatile agents decreased • Reduced dose of local anesthetics for regional anesthesia • Plasma cholinesterase levels are lower during pregnancy

12. EFFECTS OF ANESTHETIC AGENTSON THE FETUS • Inhalational agents: • Nitrous oxide may impair DNA synthesis and inhibit cell division • Forane in one study associated with anomalies • Intravenous agents: • Benzodiazepines are best avoided during organogenesis • Narcotics may be related to intrauterine fetal asphyxia • Muscle relaxants cannot cross uteroplacental barrier • Local anesthetics can cross uteroplacental barrier

13. ANESTHESIA PLAN AND MANAGEMENT • Choice of anesthetic determined by: • Surgical indication • Proposed operative procedure • Gestational age • Maternal condition • Neither general nor regional anesthesia strongly associated with increased risk to parturients • Success in outcome of pregnancy is influenced by: • Timing of surgery • Choice of medications and anesthetic agents • Promotion of fetal health and maternal well-being

14. Proposed algorithm for non-ob surgery

15. SUMMARY • Anesthetic is not risk factor for adverse perinatal outcome • Incidence of premature labor and fetal loss increases with increasing severity of underlying surgical disease and occurrence of perioperative complications • No currently used anesthetic agents have been found to be teratogenic in humans • Recommended guidelines: • Timing of surgery; delay as much as possible • Choice of drugs; consider fetal safety • Promote fetal well-being; keep maternal physiologic functions at an optimum • Promote maternal well-being; provide preoperative support