Abdominal Surgery in the Pregnant Patient

1
Abdominal Surgery in the Pregnant Patient

• Perinatal Telehealth Rounds
• November 2, 2004
• Clayton Tuffnell

2
Case Report One

• 28 y.o. G1P0 at 13wk5d LMP 9/7/2004
• Pos home pregnancy test 1/9/2004
• ER visit abdominal pain 6/9/2004
• US SLIP 8wk3d, ? Appendicitis
• 7/9/2004 laparoscopic appendectomy
• Pus noted in abdomen at surgery
• Path normal appendix

3
Case Report One

• U/S 29/9/2004 by FP to monitor pregnancy
• at 12wk 5d
• SLIP
• Mass superior right kidney
• MRI 1/10/2004
• 8cm mass right kidney
• unable to rule out malignancy
• Booked for right nephrectomy 14/10/2004

4
Case Report Two

• 32 y.o. G1P0 19wks2d GA
• RUQ pain x 1 month
• U/S 9/8/2004
• SLIP 10wk4d
• right adrenal mass

5
Case Report Two

• MRI 14/9/2004
• 5.1cm right adrenal mass, suspicious in
  appearance
• MSS Screen Negative
• Laboratory Evaluation Normal (Neg for Pheo)
• Booked for Laparoscopic adrenalectomy 26/10/2004

6
Nonobstetrical Surgical Problems

• 2 of pregnancies are complicated by
  non-obstetrical surgical problems
• Acute appendicitis occurs at the same frequency
  as in non gravid female of the same age
• Appendectomy in 12000 pregnancies in the US
• Acute cholecystitis requiring cholecystectomy
  occurs in 1 to 61000 pregnancies
• Other surgical problems include renal and adrenal
  masses, maternal trauma, breast cancer, splenic
  artery aneurysms, hepatic adenomas,
  pheochromosytoma

7
Nonobstetrical Surgical Problems

• Maternal Concerns
• Maternal physiologic changes impacting anesthesia
  
• Increased risk of thrombotic disease in pregnancy
• Gravid uterus altering surgical field access
• Laparotomy vs. Laparoscopy

8
Nonobstetrical Surgical Problems

• Fetal Concerns
• Teratogenicity of anesthetic agents
• Teratogenicity of imaging studies
• Pregnancy loss
• Preterm labour 12-43
• PROM

9
Physiologic Changes of Pregnancy

• Cardiovascular System
• cardiac output increases 30-50 and is directed
  primarily to the uterus, kidneys and skin
• resting HR increases 10-15 bpm
• decrease in systemic vascular resistance, with a
  5 to 10 mmHg decrease in systolic BP and 10 to 20
  mmHg decrease in diastolic BP

10
Physiologic Changes of Pregnancy

• Cardiovascular System
• Blood volume increases 30-50, leading to
  hemodilution
• Increase in blood volume also delays signs of
  hypovolemia, thus tachycardia and hypotension may
  not develop in response to an acute hemorrhage
  until 30-50 of the blood volume is lost

11
Physiologic Changes of Pregnancy

• Hematological System
• increased levels of estrogen lead to an increase
  in clotting factors
• predisposes to thrombosis
• ? Factors II, VII, VIII, IX and X
• ? antithrombin III and protein S
• changes inhibiting thrombosis
• ? Factors XI and XIII
• ? Plasminogen

12
Physiologic Changes of Pregnancy

• Respiratory System
• Increase in O2 consumption
• Minute vent increased 40
• Compensated respiratory alkalosis
• Increased sens of med resp centre to CO2
• Hyperventilationdecreased CO2
• Renal compdecreased HCO3-

13
Anesthetic Considerations Agents

• Nearly all agents used are pregnancy
• Category C
• No agents have been definitively shown to cause
  fetal malformation
• Paralytics do not cross the placenta
• Inhalational/local anesthetics, narcoticagents,
  benzodiazepines all shown to be safe in pregnancy
• G. Gideon Koren, A. Pastuszak and S. Ito, Drugs
  in pregnancy. N Engl J Med 338 (1998), pp.
  11281137.

14
Anesthetic Considerations Cardiovascular
Physiology

• Avoid maternal hypotension and resultant fetal
  hypoxia
• Gravid uterus may impair VC return
• Hypotension treat with aggressive fluid
  resuscitation
• LLD position for increased venous return
• Trendelenburg Pressors if concern regarding
  inability to maintain pressure

15
Anesthetic ConsiderationsRespiratory Changes

• Comp respiratory alkalosis PaCO2 30 to 35mmHg
• Difficult intubation due to increased airway
  edema
• Increased risk of aspiration due to delayed
  gastric emptying and LES tone
• Cricoid pressure
• End-tidal CO2 monitoring

16
Radiologic Considerations

• Rad exposure 1 rad1 cGy
• Animal studies, observational studies of human
  exposure, humans exposed to atomic bomb
• Greatest effects during rapid cell proliferation
  weeks 1 to 25
• Week 2-3 SA
• Week 8 to 25 central nervous system

17
Radiologic Considerations

• Neurologic Development weeks 8 to 25
• gt10 raddecrease in IQ
• gt100 radsevere mental retardation
• Childhood Leukemic Cancer
• background incidence 0.2 to 0.3
• gt1 rad less than 40 increase (0.3 to 0.4)
• may increase risk of childhood cancer by 0.06
  per 1 rad delivered to fetus
• F.A. Mettler, R.L. Brent, C. Streffer et al.,
  Pregnancy and medical radiation. Ann ICRP 30
  (2000), pp. 142

18
Radiologic Considerations

• Melnick DM. Management of general surgical
  problems in the pregnant patient. Am Journ Surg.
  187 (2004) 170-180.

19
Radiology Position Statements

• "No single diagnostic procedure results in a
  radiation dose that threatens the well-being of
  the developing embryo and fetus (American
  College of Radiology)
• Exposure to less than 5 rad has not been
  associated with an increase in fetal anomalies or
  pregnancy loss."
• (American College of Obstetrics and Gynecology)
• "Fetal risk is considered to be negligible at 5
  rad or less when compared with the other risks of
  pregnancy, and the risk of malformations is
  significantly increased above control levels only
  at doses above 15 rad.
• (National Council on Radiation Protection)

20
Thrombotic Disease in Pregnancy

• Maternal physiologic changes lead to a
  hypercoagulable state
• DVT incidence 0.1 to 0.2
• Prevention compression devises intraop and
  postop, consideration of DVT prophylaxis (sq
  heparin)
• Patient/Family Hx of VTE disease

21
Surgical Considerations Laparoscopy Benefits

• Decreased post operative narcotic requirements
  (fetal depression)
• Decreased wound complications
• Decreased post op maternal hypoventilation
• Decreased risk of VTE
• Rapid maternal recovery

22
Surgical Considerations Laparoscopy Risks

• Uterine injury during trocar/verress placement
• Decreased uterine blood flow
• Premature labour due to increase intra-abd
  pressure
• Effects of CO2 pneumoperitoneum (fetal acidosis)

23
Surgical Considerations Laparoscopy

• CO2 and pneumoperitoneum
• Concern re mild metabolic acidosis, increased
  heart rate and BP in sheep model
• Acidosis was not clinically significant and
  likely secondary to CO2 resorption as not present
  when NO used as insufflation agent
• Fetal hypercarbia reversed with mild maternal
  respiratory alkalosis
• J.G. Hunter, L. Swanstrom and K. Thornburg,
  Carbon dioxide pneumoperitoneum induces fetal
  acidosis in a pregnant ewe model. Surg Endosc 9
  (1995), pp. 272279

24
Surgical Considerations Laparoscopy

• Case Report
• Series of 47 fetal deaths
• surgeries were for acute abdominal diseases
  (perforated appendicitis, acute cholecystitis)
• cause of fetal demise was not identified
• J.D. Amos, S.J. Schorr, P.F. Norman et al.,
  Laparoscopic surgery during pregnancy. Am J Surg
  171 (1996), pp. 435437

25
Laparoscopy vs LaparotomyThe Swedish Health
Registry

• 2233 laparoscopy vs 2491 laparotomy
• 1973 to 1993
• Singleton pregnancies
• OR weeks 4 to 20
• Outcomes birth weight, gestation duration,IUGR,
  congenital malformations, stillbirth, neonatal
  death

26
Laparoscopy vs LaparotomyThe Swedish Health
Registry

• Comparison of gestational duration in laparoscopy
  and laparotomy cohorts with total population.

27
Laparoscopy vs LaparotomyThe Swedish Health
Registry

• Comparison of birth weight in laparoscopy and
  laparotomy cohorts with total population. RR,
  Risk ratio

28
Laparoscopy vs LaparotomyThe Swedish Health
Registry

• Comparison of growth-restricted infants by SD
  scores in laparoscopy and laparotomy cohorts with
  total population

29
Laparoscopy vs LaparotomyThe Swedish Health
Registry

• Increased Risk with surgery
• BW less than 2500g
• Delivery prior to 37 weeks
• IUGR
• No difference between laparoscopy and laparotomy
• Infant survival at 1 yr (OR 0.85)
• Fetal malformation (1.08 and 1.09)

30
USC Womens Hospital

• Retrospective review 1991 to 1998
• 88 laparotomy vs. 18 laparoscopy
• Mean GA at surgery 13.7 weeks
• Preterm delivery 18
• Laparotomy Laparoscopy
• Emergency surgery increased PTD
• No difference in preterm delivery or SA rates
  from institutional rates

31
When Do I Operate?

• First Trimester
• increased risk of SA
• period of greatest organogenesis for exposure to
  phamracologic agents and radiation

32
When Do I Operate?

• Third Trimester (or beyond viability)
• Increased risk of preterm labour and PROM
• Intraoperative monitoring
• Intraoperative intervention
• Postoperative monitoring

33
When Do I Operate?

• Second Trimester
• no intraoperative monitoring required
• minimal post operative monitoring required
• no intervention (pre-viability)
• may decide to alter antepartum care in required

34
ACOG Committee Opinion

• The American College of Obstetricians and
  Gynecologists Committee on Obstetric Practice
  acknowledges that the issue of nonobstetric
  surgery and anesthesia in pregnancy is an
  important concern for physicians who care for
  women however, there are no data to allow us to
  make specific recommendations.

35
SAGES Committee Opinion

• Obtain an obstetric consult preoperatively
• Delay elective cases until second trimester
• Use lower ext pneumatic compression devises
  (pregnancy and pneumoperitoneum may induce a
  hypercoagulable state
• Follow maternal and fetal physiologic status
  intraoperatively (maternal end tidal CO2)

36
SAGES Committee Opinion

• Protect uterus with lead shield for
  intraoperative cholangiography
• Use open technique to gain pneumoperitoneum
• Tilt table left side down to move gravid uterus
  off vena cava
• Minimize pneumoperitoneum to 8 to 12 mm Hg

37
Questions