Conference Lectures

Laparoscopic Surgery in a Parturient- Anaesthetic Implications
Prof. Jayashree Sood, MD, FFARCS, PGDHHM, FICA
Chairperson
Dept. of Anaesthesiology, Pain and Perioperative Medicine
Sir Ganga Ram Hospital, New Delhi.

Nonobstetric general surgery procedures are required in approximately 1 in 635 pregnancies. Symptomatic gallbladder disease and acute appendicitis are the most frequent indication for non-gynecologic procedures during pregnancy. Gallstones are present in 12% of all pregnancies. CO2  laparoscopic cholecystectomy during pregnancy is preferred because of the good outcomes and low rate of complications. The incidence of adnexal masses during pregnancy is 2%. In the event surgery is indicated, various case reports advocate the use of laparoscopy in its management in every trimester. 

A few years back laparotomy was considered as the gold standard for all intra-abdominal surgeries in pregnant patients. In fact laparoscopic surgery was contraindicated in pregnancy due to the various pathophysiological changes of laparoscopy which would probably superimpose on the already existing changes associated with pregnancy. However with more technical advancement and expertise, laparoscopy has now become the technique of choice as compared to laparotomy in a pregnant patient due to various advantages associated with it.

A few basic, but important, concerns which arise when dealing with a pregnant patient undergoing laparoscopic surgery are; the maternal physiologic alterations associated with pregnancy, factors unique to pregnancy and carboperitoneum that can affect uteroplacental blood flow,  the overall effect of these influences on the well being of the fetus and surgical considerations such as space, trocar insertion and manipulation.

Physiological adaptations and changes occur early in pregnancy and continue throughout gestation; hormonal changes in the first trimester, mechanical effects of the gravid uterus in the second trimester and increasing metabolic demand throughout pregnancy. There is an increase in oxygen demand and consumption during pregnancy. There is a reduction in the functional residual capacity by about 20 per cent due to the gravid uterus pressing on the diaphragm.

The cardiac output starts to increase as early as five weeks of gestation and increases up to 40 per cent above the non pregnant state by the end of second trimester. Mean arterial blood pressure falls due to the effect of progesterone on the vascular system. The gravid uterus presses on the inferior vena cava in the supine position resulting in hypotension and a reduction in cardiac output of 25-60 per cent (supine hypotension). Introduction of carboperitoneum, coupled with aortocaval compression further accentuates the hypotension. The addition of reverse Trendelenburg position further produces a fall in blood pressure. A combination of reverse Trendelenburg position, general anaesthesia and peritoneal insufflation decreases the cardiac index by as much as 50 percent.

The renal plasma flow and GFR increase rapidly during the first trimester of pregnancy. The effect of carboperitoneum on urine output, although reversible requires adequate hydration preoperatively and careful surveillance intraoperatively to optimize renal blood flow.

The pregnant woman becomes hypercoaguable as gestation progresses. Factors VII, VIII, X and fibrinogen are markedly increased. Two of the factors in the Virchow’s triad (hypercoaguability and venous stasis) are affected in laparoscopy; therefore, the hypercoaguable state of pregnancy along with the DVT susceptibility in laparoscopy, places the parturient at substantial risk of DVT during the raised IAP produced by carboperitoneum. Graded compression stockings, intermittent pneumatic compressions with or without prophylactic subcutaneous heparin at the onset of surgery should be the standard protocol.

The pregnant patient is at a high risk of silent gastric regurgitation and pulmonary aspiration due to effect of progesterone and mechanical consequences of the gravid uterus producing a change in the angulation of the gastroesophageal junction. In laparoscopic surgeries, creation of carboperitoneum increases the tone of the lower esophageal sphincter and thus increases the barrier pressure.
Normal uterine blood flow at term is 600-700 ml per minute. Any decrease in maternal blood pressure due to supine hypotension syndrome or increased IAP (carboperitoneum) will further decrease uterine blood flow. The introduction of carboperitoneum leads to activation of the renin angiotensin pathway which leads to increased uterine vascular resistance which further decreases the uteroplacental blood flow.

The incidence of fetal congenital anomaly is less than two of 400 laparoscopies in pregnancy in study by Bisharah et al and they have concluded that it is unlikely that laparoscopy is the cause.
The second trimester is the optimal time to operate as organogenesis occurs in the first trimester and the susceptibility to induce premature labor and delivery in the third trimester.

During laparoscopy the position of the patient is altered several times to produce gravitational displacement of the viscera away from the surgical side. The Trendelenburg, reverse Trendelenburg, the left lateral tilt to avoid supine hypotension produce several haemodynamic and respiratory alterations.

Monitoring of a pregnant patient undergoing laparoscopy include the following parameters;  heart rate, NIBP, SpO2, EtCO2, uterine contractions, fetal heart doppler, intra-abdominal pressure, airway pressure, and urine output.Meticulous monitoring of a pregnant patient is important as the surgery involves two lives instead of one. Bhavani Shankar et al states that there is little difference in the PaCO2 and EtCO2 levels (0.03 mmHg) and thus end tidal CO2 is a good reflection of maternal PaCO2 and is an essential monitor. They have also concluded that arterial blood gases monitoring during laparoscopy in pregnant patients with healthy lungs is not necessary. As with any surgical patient, adequate hydration, careful monitoring of urine output are of paramount importance. The SAGES guidelines clearly states that the intra-abdominal pressure should be minimized to 8-12 mmHg and not allowed to exceed 15 mmHg. Therefore, a strict monitoring of the intra-abdominal pressure is mandatory.

Consultation with the neonatal team is integral in the planning of a possible emergent delivery of fetus and in informing the prospective parents of survivability at the gestational age in question.
Certain guidelines – should be routinely adopted to enhance operative safety. SAGES- guidelines for laparoscopic surgery during pregnancy are:

  1. Place the patient in the left lateral decubitus position as with open surgery to prevent uterine compression of the inferior vena cava. Minimising the degree of reverse Trendenlenburg position may also further reduce possible compression of the inferior vena cava.
  2. An open Hasson technique for gaining access to the abdominal cavity is safer than a closed percutaneous technique as the potential for puncture of the uterus or intestine still exists, especially with increasing gestational age.
  3. Maintain the intra-abdominal pressure as low as possible. A pressure less than 12-15 mmHg should be used until concerns about the effects of high intra-abdominal pressure on the fetus are answered.
  4. Continuously monitor maternal EtCO2 and maintain it between 25-30 mmHg by changing the minute ventilation. Promptly correcting any maternal acidosis is critical as the fetus is typically slightly more acidotic than the mother.
  5. Use antiembolic devices to prevent deep venous thrombosis
  6. Use continuous intraoperative fetal monitoring. If fetal distress is noted, release the carboperitoneum immediately.
  7. If intraoperative cholangiography is to be performed, protect the fetus with a lead shield to protect it from radiation exposure.
  8. Minimize operating time – several studies have demonstrated a direct relation between the duration of carboperitoneum and an increase in PaCO2.
  9. Tocolytic agents should not be administered prophylactically. If there is any evidence of uterine irritability then they have a role.

Several years ago, some argued that laparoscopy was contraindicated during pregnancy. However, the use of the minimally invasive laparoscopic approach in the surgical treatment of diseases during pregnancy has been progressively more accepted and applied as data supporting its safety and enhancements in use have accumulated.

 

 

Recommended Reading

  1. Sesti F, Pietropolli A, Sesti FF, Piccione E. Gasless laparoscopic surgery during pregnancy: evaluation of its role and usefulness. Eur J Obstet Gynecol Reprod Biol 2013;170(1):8-12.
  2. Jayaraman L, Sood J. Laparoscopic surgery in pregnancy. In: Anaesthesia in laparoscopic surgery. Sood J, Jain AK (editors). Jaypee Brothers Medical Publishers  2007 pg 158-66.
  3. Corneille MG, Gallup TM, Bening T, Wolf SE, Brougher C, Myers JG, Dent DL, Medrano G, Xenakis E, Stewart RM. The use of laparoscopic surgery in pregnancy: evaluation of safety and efficacy. Am J Surg 2010;200(3):363-7.