|Year : 2011 | Volume
| Issue : 2 | Page : 88-91
Super obese 33-week parturient undergoing an urgent laparoscopic bowel resection: A case report and review of anesthetic implications
Yury Khelemsky, Danielle M Gluck
Department of Anesthesiology, The Mount Sinai Medical Center, New York, USA
|Date of Web Publication||17-Mar-2012|
One Gustave L. Levy Place, KCC 8th Floor, Box 1010, New York, NY 10029
Source of Support: None, Conflict of Interest: None
Approximately two percent of women undergo non-obstetric surgery during their pregnancies. The following case report describes the anesthetic management of a super obese parturient in her third trimester of pregnancy undergoing urgent laparoscopic (converted to open) bowel resection. Such a case, which has not been previously reported, has multiple clinical implications for both mother and fetus and was further complicated by super obesity (BMI>50) and laparoscopy. The anesthetic implications for this patient population are reviewed.
Keywords: Anesthesia, laparoscopic surgery, parturient, pregnancy, super obesity
|How to cite this article:|
Khelemsky Y, Gluck DM. Super obese 33-week parturient undergoing an urgent laparoscopic bowel resection: A case report and review of anesthetic implications. J Obstet Anaesth Crit Care 2011;1:88-91
|How to cite this URL:|
Khelemsky Y, Gluck DM. Super obese 33-week parturient undergoing an urgent laparoscopic bowel resection: A case report and review of anesthetic implications. J Obstet Anaesth Crit Care [serial online] 2011 [cited 2018 Nov 15];1:88-91. Available from: http://www.joacc.com/text.asp?2011/1/2/88/93994
| Introduction|| |
A significant number of women undergo non-obstetric surgery during their pregnancies. We describe a case of successful anesthetic management a super obese parturient in her third trimester of pregnancy undergoing urgent laparoscopic bowel resection. Anesthetic and surgical considerations of this case are outlined.
| Case Report|| |
A 26-year-old female, primigravida at 33 weeks' gestation, presented for a partial colectomy secondary to a draining abscess from newly diagnosed Crohn's disease. Past medical history was significant for mild intermittent asthma, severe gastro-esophageal reflux disease (GERD), deep vein thrombosis/pulmonary embolism (DVT/PE) and super obesity (148 kg, BMI 52.5). Her medications included albuterol, as needed. On examination, the patient was afebrile with stable vital signs. She had a Mallampati class I airway, with adequate mouth opening, thyromental distance, and cervical range of motion. Neck circumference was measured at 15 inches (38 cm).
Prior to surgery, there was a discussion between the surgical, maternal fetal medicine (MFM), and anesthesiology teams regarding the multiple perioperative considerations. It was decided that continuous intraoperative FHR monitoring would not be technically feasible; however, a fetal ultrasound was performed by MFM service in the holding area. The patient was also offered an epidural catheter for intraoperative and postoperative analgesia, which was refused. Metoclopramide 10 mg IV, Glycopyrollate 0.4 mg IV, and Famotidine 20 mg IV were administered approximately 45 min before entering the OR suite via an in-situ 22G IV cannula. Thirty milliliters of a non-particular antacid was administered en-route to the operating room.
Upon entering the operating room, the patient assisted us in positioning her in a ramped (external auditory meatus horizontally aligned with sternal notch) position with left uterine displacement. Standard American Society of Anesthesiologists monitors were applied. After a full pre-oxygenation (EtO 2 of 91%), a rapid sequence induction was performed with propofol 250 mg and succinylcholine 140 mg. The trachea was intubated with a 7.0-mm-cuffed endotracheal tube with the aid of a video laryngoscope (GlideScope®). A BIS TM (Aspect) monitor was applied. A left radial arterial line (20G) and a right internal jugular central line (7F) were inserted with the aid of ultrasound after intubation.
Anesthesia was maintained with Desflurane (minimum MAC of 1), oxygen 80%/ air 20%, fentanyl, and vecuronium. Mean arterial pressure was maintained above 70 mm Hg with crystalloid fluid boluses (total volume 5000 mL) and intermittent infusion of phenylephrine (total dose approximately 2000 mcg). A pressure control, volume guarantee (PCVG) ventilator mode (GE Aisys® Carestation®) was employed to maintain adequate ventilation and oxygenation while minimizing peak inspiratory pressures. Tidal volumes of 650 mL were achieved with peak pressures not exceeding 30 cm of H 2 O. Arterial blood gas analysis aided in the maintenance of normal physiologic parameters. The surgical team was asked not to exceed abdominal insufflation pressures above 15 cm of H 2 O in order to ensure adequate uteroplacental perfusion. Approximately after two hours of laparoscopy, the case was converted to an open laparotomy due to the extent of the necessary resection. The procedure was successfully completed in 5 hours. Neuromuscular blockade was reversed with neostigmine 5 mg and atropine 1, and the patient was extubated uneventfully. A fetal ultrasound in the PACU revealed no changes from the pre-procedure baseline.
| Discussion|| |
Although not ideal, approximately two percent of women undergo non-obstetric surgery during their pregnancies.  Therefore, in such urgent situations, it is important for the anesthesiologist to understand the physiologic and anatomic changes in the mother, as well as the maternal and fetal implications of the anesthetic - especially when complicated by obesity and laparoscopic surgery. Major maternal risks in the perioperative period include problems associated with a difficult airway (i.e. hypoxia, hypercarbia, airway damage, etc.), aspiration, and hypotension, while fetal risks include decreased uteroplacental perfusion, preterm delivery, and exposure to possible teratogens.  Key points in the management of this case are summarized in [Table 1].
Obesity and pregnancy are associated with an increased incidence of difficult ventilation and intubation, as well as gastric aspiration. As this patient, on examination, had a completely normal airway, we chose to proceed with a rapid sequence induction. Metoclopramide was given early to facilitate gastric emptying, famotidine to decrease production of gastric acid, glycopyrrolate to decrease oral secretions, and a non-particulate antacid to increase gastric pH. A video laryngoscope was only employed in order to allow the attending anesthesiologist to monitor the resident's progress in real time, as it appears that intubation of obese patients with a video laryngoscope does not confer any significant advantage.  The patient was extubated while awake, after return of protective airway reflexes in order to avoid aspiration.
A major physiologic change during pregnancy is increased alveolar ventilation upwards of 70% towards the end of term, mostly as a result of increased tidal volume. The increased minute ventilation is required to support the increase in oxygen consumption by the growing placenta and fetus; therefore, a compensated respiratory alkalosis is typically present in parturients. It is vital to avoid both hypo- and hyperventilation in these patients, as these states may result in maternal-fetal acidosis or maternal alkalosis, respectively. Maternal alkalosis may lead to umbilical vasoconstriction and left shift of the hemoglobin dissociation curve resulting in fetal hypoxia. Functional residual capacity (FRC) decreases by 10-25%, especially in the supine position, secondary to increased intra-abdominal pressure and the diaphragm moving cephalad.  With a decreased FRC and increased oxygen consumption patients are prone to rapid desaturation. Obesity further complicates management as it results in further increase in oxygen consumption and decrease in FRC. The combination of obesity, pregnancy, and laparoscopic surgery (both due to insufflation pressure and systemic uptake of CO 2 ) presents the anesthesiologist with the challenge of maintaining adequate oxygenation and ventilation, while minimizing inspiratory pressures. 
We were able to precisely oxygenate and ventilate this patient with relative ease by utilizing a Pressure Control/Volume Guarantee ventilator mode, avoiding the Trendelenburg position, minimizing surgical insufflation, and monitoring arterial blood gases (target pH 7.35-7.45). In addition, the patient was extubated in a semi-upright position while completely awake in order to maximize her FRC and respiratory effort.
Cardiac output progressively increases during pregnancy due to increase in heart rate, and, more significantly, stroke volume. Obesity also results in a substantial increase in cardiac output along with a decrease in systemic vascular resistance during pregnancy.  In order to maintain adequate maternal and uteroplacental (fetal) perfusion, which is directly dependent on the mean arterial pressure, both the cardiac output and the systemic vascular resistance (SVR) must be maintained.  We achieved this by placing the patient in left uterine displacement position, use of minimal effective tidal volume (650 mL), and positive end expiratory pressures (5 cm of H 2 O), providing vasopressor support when needed, and ensuring that abdominal insufflation pressures did not exceed 15 mm Hg.  An arterial line and a central venous catheter were placed shortly after induction to assist with rapid identification and treatment of hypotension.
Pregnancy has been documented to be associated with increased sensitivity to both intravenous and inhalational anesthetic agents.  A reduction in minimal alveolar concentration up to 40% has been found during pregnancy.  Obesity is also associated with sensitivity to various anesthetic agents, including opioids. In order to optimize anesthetic administration, a BIS monitor was applied. However, as end-tidal concentrations of volatile anesthetic were able to be maintained above 1 MAC for the duration of the case the concern for awareness was minimal. The trachea was extubated in a semi-recumbent (45 degree) position only when the patient was completely awake.
In addition to the fetal risk from disturbances in maternal hemodynamics, teratogenic malformations due to anesthetic medications and possibility of preterm labor and delivery pose additional threats. Since the major organogenesis occurs in the first trimester, teratogenesis was not a concern in this case.
Our main concern was pre-term labor, which is typically unrelated to the anesthetic and more dependent on the surgery being performed.  In our case, a laparoscopic abdominal surgery placed our patient at an increased risk of preterm labor secondary to manipulation of intra-abdominal structures, specifically the uterus. In addition to the surgeon's efforts to avoid manipulation of the uterus, we utilized Desflurane at the highest tolerated concentration as a tocolytic. Although complete uterine relaxation requires up to 2 MAC of volatile anesthetic, effective tocolysis may be achieved with much lower concentrations, which in this case was approximately 1 MAC.  Magnesium and nitroglycerin (along with a MFM physician) were readily available if further tocolysis was required. While there are reports of intraoperative fetal heart rate monitoring in the literature, the 2009 American Society of Anesthesiologists Statement on Non-Obstetric Surgery during pregnancy notes that such monitoring is not mandatory - but may be considered in select patients. , Monitoring was not employed in this case as it was physically impossible.
| Conclusion|| |
The anesthetic management of a super obese 33-week pregnant female undergoing abdominal laparoscopic surgery is described. A multidisciplinary approach involving the anesthesiologist, surgeon, and MFM physician is essential to address the complex perioperative management of such cases.
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