Anesthetic management of a pregnant patient with pseudo-pancreatic cyst for cysto-gastrostomy.

Non-obstetric diseases during pregnancy are not uncommon. The presence of systemic disease may further insult the pregnancy leading to alteration in the normal function of other system. Hence, it is important to treat the disease depending upon the severity and type of urgency. Several systemic diseases in pregnancy and management have been reported earlier but it is necessary to report a rare pathology, treatment option and its anesthetic management. We report anesthetic management of a rare case of pseudo pancreatic cyst in a pregnant lady operated for cysto-gastrostomy and also highlighting the recent guidelines for non-obstetric surgery in pregnancy.

INTRODUCTION

Non-obstetric surgeries during pregnancy are not uncommon. The surgeries during pregnancy mostly performed to treat obstetric or non-obstetric pathology. There is a lack of data from the developing countries, but 1-2% of the pregnant lady is undergoing non-obstetric surgery.[1] Surgeries during pregnancy are performed to treat either obstetric or non-obstetric pathology. Out of all, obstetric causes commonly seen are cervical incompetence for cervical encirclage and ovarian cyst for excision or cystectomy. The non-obstetric causes are most commonly the acute abdomen due to appendicitis, cholecystitis, maternal accidental trauma and maternal malignancies.[2] Less commonly cardio-respiratory systems require surgical interventions during pregnancy. Present article highlights recent guidelines on anesthetic management of a pregnant patient suffering with pseudo-pancreatic cyst posted for cysto-gastrostomy.

CASE REPORT

A 30-year-old lady, primigravida with 20 weeks of pregnancy presented to our hospital with the chief complaints of pain and distention of the abdomen since 1 month. The pain was continuous, dull aching and localized in epigastric, right hypochondriac and para-umbilical region. The patient noticed distention of the abdomen since 1 month which was insidious in onset and gradually progressive in nature. There was no history of fever, vomiting, yellowish discoloration of the sclera or high colored urine. The pregnancy was confirmed by trans-vaginal ultrasonography (USG) examination, which revealed a living singleton fetus. The patient was operated in the past when she was 3 years old for cleft lip repair under general anesthesia and was uneventful. There was no other significant history in the past.

On general physical examination, she was conscious, oriented, weighing 40 kg, height of 150 cm, pulse rate 80/min and blood pressure (BP) of 130/80 mm Hg. Abdominal examination showed a uniform distention with tenderness in right hypochondriac and para umbilical areas. Cardio respiratory systems were within normal limits. Airway assessment revealed Mallampatti class I.

Routine investigations such as hemoglobin, complete blood count, renal function test and liver function tests were normal except for raised serum amylase (764 IU/L). Ultrasound abdomen revealed gravid uterus with live intrauterine fetus of 20 weeks. Parenchyma of pancreas appeared to be slightly compressed, a large walled collection measuring 127 mm × 75 mm × 1 00 mm in size seen in the retro-gastric region and cyst appeared bilobed. No ductal dilatation or calcific foci noticed.

The patient received tablet ranitidine 150 mg, tablet midazolam 7.5 mg night before surgery and injection medroxiprogestrone (I.M) 250 mg before taking up for surgery. On the day of surgery injection ranitidine, injection metoclopramide intravenously (IV) was given 1 h prior to surgery. A large bore IV cannula was secured and received 500 ml of ringer lactate as preloading. All standard monitoring such as electrocardiogram, oxygen saturation and noninvasive BP were done. After explaining the plan of anesthetic procedure to the patient, an epidural catheter was secured at the T10-11 inter-space by loss of resistance to air technique and confirmed. The patient was put in the supine position with wedge below right hip for left uterine displacement. Patient received Inj. Midazolam 0.03 mg/kg, Inj Fentanyl 1 mcg/kg IV. Pre-oxygenation was done for 3 min with 100% oxygen and induced with Inj Thiopentone 5 mg/kg, Inj Succinylcholine 1 mg/kg along with Sellick's manure. Intubation was done with 7 mm cuffed endotracheal tube and bilateral air entry confirmed. Anesthesia was maintained with O2:air (1:1), Inj vecuronium, Inj Fentanyl, sevoflurane (Dial concentration adjusted between 1.5% and 2%). The patient was put on the volume control mode of ventilation and the settings were done to maintain end tidal carbon dioxide (ETCO2) of 35-45 mm Hg. 10 ml of Inj Bupivacaine (0.5%) was injected through the epidural catheter before incision in a titrated manner to prevent sudden hypotension. In our case there was no significant fall in the BP noticed. Throughout the surgery the systolic BP was maintained around 110-130 mm Hg, diastolic BP around 70-90 and mean around 55-70 mm Hg. Total surgical duration was 1 h with blood loss of 150 ml. She received a total of 1L of IV fluid (500 ml RL + 500 ml NS). At the end of the surgery reversal was done with Inj Gglycopyrrolate of 0.4 mg and Inj Neostigmine 2.5 mg IV. Extubation was done once criteria were met. The patient was conscious, spontaneously breathing and pain free. She was shifted to the high dependence unit (HDU) for further management. For post-operative pain relief she received 0.125% of Inj Bupivacaine infusion 6 ml/h through epidural and the visual analogue score was maintained less than 5. There was no hemodynamic instability in the post-operative period. Post-operative USG revealed single live fetus average gestation of 20 ± 2 weeks in variable presentation; low lying placenta reaching the margin of internal OS. She was discharged after 48 h from HDU. Post operatively Inj progesterone 250 mg (I.M) was repeated after 1 week.

DISCUSSION

Pseudo-pancreatic cyst during pregnancy is a rare condition. Different non obstetric surgeries are performed during pregnancy, depending on the urgency and emergency. Surgery should be postponed if the disease doesn’t require emergency intervention, in view of maternal and fetal well-being. The surgery was planned in our patient to treat it and also to prevent further complications. Main aim should be to save the life of mother while taking care to minimize the risk of miscarriage and preterm delivery.[23] We pre-medicated the patient with tablet ranitidine 150 mg, tablet midazolam 7.5 mg previous night before the day of surgery. Aspiration prophylaxis injection ranitidine and injection metoclopramide (IV) was given prior to surgery. It is important to consider the pregnant patient as full stomach and follow the guidelines.[45] The most important and serious risk to the fetus is intrauterine asphyxia during maternal surgery. According to the latest guidelines by “The American College of Obstetricians and Gynecologist,” pre- and post-surgical procedure confirmation of fetal heart rate by Doppler is generally sufficient if the fetus is pre-viable. Intra-operative electronic fetal monitoring should be done if the fetus is viable, physically possible to perform, patient has given informed consent for emergency cesarean delivery, obstetrician is available and willing to intervene during the surgical procedure for fetal indications and if the nature of the planned surgery allows the safe interruption or alteration of the procedure to provide access to perform emergency delivery.[6] Since in our patient the fetus was pre-viable, also the surgery was laparotomy we assessed the condition of the fetus before and after the procedure. A wedge was placed under right hip joint for left uterine displacement to improve utero-placental blood flow. The left uterine displacement is recommended in pregnant patients of 20 weeks and above.[7] Since the surgery was involving upper abdomen, we did choose combined general and epidural anesthesia as epidural will provide very good analgesia in the peri-operative period.

A combination of general and epidural anesthesia reduces analgesic and anesthetic agent requirement, better intraoperative hemodynamic stability, suppressed metabolic, endocrine and immunologic responses.[89] Management of these responses with good post-operative analgesia is important in reducing post-operative morbidity and mortality. Hence the combination has an advantage of early recovery and mobilization.

The main controversy lies in type of anesthesia for non-obstetric surgery during pregnancy since all general anesthetic drugs cross the placenta.[1011] It is important that whatever type of anesthesia, the goal should be to maintain stable hemodynamics, perioperative good analgesia, avoid drugs having teratogenicity, maintain good utero-placental flow and prevent intra-op fetal hypoxia and acidosis.[12] Studies have shown that hypnotic drugs, opioids and sedatives do not have deleterious effects on the developing embryo or fetus.[3] Since there is weak evidence that nitrous oxide leads pregnancy loss and vasoconstructive property it should be avoided.[1113] All anesthetic agents including volatile agents can be used in pregnancy. Volatile anesthetic agents prevent premature uterine activity.[2] Many studies have shown regional anesthesia is better than general anesthesia due to two things, first, avoidance of poly-pharmacy and second avoidance of the airway. The largest risk of regional anesthesia is hypotension resulting from sympathetic nerve blockade there by reducing uterine blood flow and perfusion to the fetus. The anesthesia technique should be individualized depending upon surgical site. The general anesthesia is not an absolute contraindication but if some important precautions such as, prophylaxis against aspiration, avoidance of unnecessary drugs and proper airway management are followed, and then it can be a superior technique. Whenever possible epidural should be combined with general anesthesia due to various advantages as mentioned above.

It is important to monitor and maintain normal ETCO2 during general anesthesia, as hypocarbia due to hyperventilation impairs fetal oxygen delivery by shifting maternal oxygen-hemoglobin dissociation curve to the left.[13] Fetal respiratory acidosis can be a result of maternal hypercarbia which can lead to fetal myocardial depression. Hypercapnia also results in uterine artery vasoconstriction and reduced uterine blood flow.[14]

Different tocolytics like calcium channel blockers, magnesium, beta agonists and oxytocin receptor blockers are used depending upon the pregnancy period to prevent preterm delivery. Post-operatively, patients should be monitored for contractions and treated with tocolytic agents when appropriate.[15] It is important to keep in mind that these drugs may interact with anesthetic drug. In our patient obstetrician advised injection progesterone which was given peri-operatively. Animal studies showed that the progesterone at higher dosage decreases the minimum alveolar concentration value of sevoflurane.[16]

If the treatment options are considered the minimal invasive or endoscopic surgeries have higher advantages than open surgery due to no or minimal exposure to anesthetic drug, lesser surgical stress, avoidance of prolonged hospital stay, early recovery and lesser economic burden. A recent study showed cysto-gastrostomy when performed endoscopically has higher advantages than open surgical technique.[17] It is important to know all types of treatment options are not available in developing and underdeveloped countries but it is always better to consider for minimal invasive procedure whenever possible.

CONCLUSION

One should keep in mind that, any emergency surgery can be performed in any trimester depending on the type of urgency. Whenever possible surgeries should be considered in the second trimester as spontaneous abortion is less likely. General anesthesia is not an absolute contraindication but the combination of regional and general anesthesia has got better outcome. Multidisciplinary approach in the peri-operative period involving anesthesiologist, obstetrician, surgeon and neonatologist should be considered when applicable for a better outcome.