PBLD3: Care of the Parturient with Pre-eclampsia Tweet to @SOAPhq Case Description A 38-year-old G1P0 at 38 weeks and 2 days gestational age, is admitted to the labor and delivery floor for induction of labor (IOL) for severe pre-eclampsia. Upon admission, the patient is complaining of mild frontal headache. She is not in labor so she has no pain. In the fetal evaluation unit, her blood pressure (BP) ranges between 140/85-195/114 mmHg, and she is therefore admitted on the labor and delivery floor for IOL for pre-eclampsia (PEC) with severe features. The anesthesia team is immediately consulted regarding the possibility of an epidural for IOL. However, her past medical history is still unknown to the OB team at this time, since the patient just arrived on the floor. 1. List 5-10 elements of history, physical exam, or additional workup that will aid you in building your anesthetic plan. Laboratory work including platelet count and coagulation studies Prior laboratory values for comparison Obstetric plan for management of PEC (including administration of antihypertensives or magnesium) Patient’s additional comorbidities including obesity or significant cardiac or pulmonary disease Airway evaluation 2. Which of the following criteria are required for the diagnosis of PEC with severe features? a. Persistent elevated blood pressures ≥ 160 mm Hg systolic or ≥ 110 mm Hg diastolic without any other disturbances b. Clinical signs such as frontal headache, visual disturbances, epigastric pain c. Proteinuria above 300mg d. Isolated thrombocytopenia e. a+b f. a+b+c According to the new ACOG guidelines1, the diagnosis of pre-eclampsia no longer requires the detection of any level of proteinuria. Evidence shows end organ damage (kidneys, liver, eyes) can occur without proteinuria, and that the amount of protein in the urine does not predict how severely the disease will progress2. Pre-eclampsia is now diagnosed by persistent hypertension that develops during pregnancy or during the postpartum period associated with at least one of the following: new onset of thrombocytopenia, impaired liver or kidney function, pulmonary edema, or neurological sequelae such as seizures and/or visual disturbances. Elevated levels of urine protein are frequently present but not required for the diagnosis. References ACOG. American College of Obstetricians and Gynecologists Task Force on Hypertension in Pregnancy, Hypertension in Pregnancy. November 2013. Homer CS, Brown MA, Mangos G, Davis GK. Nonproteinuric pre-eclampsia: a novel risk indicator in women with gestation hypertension. J Hypertens 2008;26:295-302. 3. What are some of the side effects of magnesium administration? a. Floppy baby b. Excessive maternal drowsiness c. Resistance to general anesthesia d. Seizure e. a+b f. a+b+c Magnesium sulfate is used as a tocolytic and anticonvulsant in parturients with pre-eclampsa/eclampsia. It is also a powerful sedative medication inducing maternal drowsiness and floppy baby. In addition, anesthetic requirements are reduced when magnesium has been utilized. This is the result of both decreased release of presynaptic acetylcholine and decreased motor end-plate sensitivity to acetylcholine. This end-plate effect results in an increased sensitivity to both depolarizing and non-depolarizing muscle relaxants. NMDBs have a reduced ED50 and onset time, and increased duration of action. Magnesium administration does not cause seizures, but rather is used to prevent their occurrence. Reference Walton JR, Grobman WA. “Preterm Labor and Delivery.” Chestnut’s Obstetric Anesthesia: Principles and Practice. Ed. David H. Chestnut, Cynthia A. Wong, Lawrence C. Tsen, Warwick D. Ngan Kee, Yaakov Beilin, and Jill M. Mhyre. 5th ed. PA: Philadelphia, 2014. 787-808. Additional Case Information Because of the lack of adequate information on this patient, you decide to postpone any intervention until the 8 am morning sign out where the patient’s case is going to be discussed with MFM. At sign out, you understand that the patient has been started on magnesium and the first laboratory results from 7 am are still pending. Her previous labs from 2 weeks ago showed a platelet count of 215K and normal coagulation values. The induction was started right away with Oxytocin infusion and it appears that the patient is already experiencing moderate to severe pain with the contractions. After sign out, you go to evaluate the patient. You find her to be extremely drowsy in between contractions, but her pain is a 9/10 when the contractions occur. The rest of your anesthesia assessment is as follows: morbid obesity with a BMI of 44, short neck, large tongue, class IV airway, gestational diabetes diet-controlled, otherwise healthy patient. The pregnancy was uneventful until now except for fetal macrosomia. The patient has 2 large bore peripheral IV’s and is type and crossed. You would like to offer her neuraxial analgesia. 4. List 5-10 concerns you have about this patient given the above history and physical exam. The difficult airway anticipated by your clinical evaluation Association of gestational diabetes and large baby increasing the risk of shoulder dystocia and potential for emergent cesarean delivery Ability to obtain informed consent for anesthesia in a drowsy patient Inability to offer regional anesthesia if the patient’s repeat laboratory values are abnormal The possibility of urgent or STAT cesarean delivery occurring before further workup can be completed Additional Case Information A half hour later once the laboratory results are back, you reassess the patient. She is not as drowsy as on initial evaluation since the magnesium has been held, but she is now complaining of increased pain. Unfortunately, the results of her PEC labs show marked thrombocytopenia of 85K, coagulopathy with an INR of 1.6, elevated AST and ALT at twice the normal values. At this point, the patient is diagnosed with HELLP syndrome. 5. In this case, what are the contraindications to neuraxial placement? a. Thrombocytopenia with a platelet count of 85,000 b. Coagulopathy with an INR of 1.6 c. Concomitant magnesium treatment d. a+b According to guidelines published by the American Society of Regional Anesthesia and Pain Medicine (ASRA)4, the only real contraindication to neuraxial anesthesia in the choices given is an elevated INR above 1.5. Isolated thrombocytopenia with normal INR, depending on the etiology of the low platelets and the trend, might not be an absolute contraindication, especially in the context of a difficult airway as presented in this case. You might consider a spinal for cesarean delivery or even neuraxial anesthesia for labor. Reference Horlocker TT, Wedel DJ, Rowlingson JC, et al. Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy. Regional Anesthesia and Pain Medicine 2010; 35: 64–101. 6. Because this patient is not considered a candidate for the placement of neuraxial analgesia, you decide to offer her a remifentanil PCA (Patient Controlled Analgesia) for treatment of labor pain. Describe reasonable PCA settings (bolus dose, lockout time) for delivery of remifentanil and any limitations that might be encountered in regards to the pump settings? Bolus dose: 0.25-0.5 µg/kg Lockout time: 2 minutes – some pumps have a minimum lockout time of 5 minutes, which is greater than the time between contractions and may necessitate basal background infusion 7. List 3 side effects of remifentanil administration Itchiness Nausea Drowsiness Respiratory depression 8. List specific risks and benefits of intravenous remifentanil PCA during labor? Remifentanil is an ultra-short acting opioid that can be administered by an anesthesiologist, and its use requires a higher level of nursing care of the parturient. Additional monitoring requirements for the patient can include a pulse oximeter and respiratory rate checks. Some institutions prefer the continuous infusion without bolus or a combination of both infusion and bolus, which must be tailored to your patient and her comorbidities. Pro: Remifentanil provides better pain relief than intermittent pushes of longer lasting opioids, because of its short half-life. It can be administered to patients with a contraindication to regional anesthesia. Remifentanil PCA with a bolus dose in the range of 0.25-0.5 µg/kg and a lockout time of 2 min appears to be a safe and effective option for use in labor with patient‐controlled analgesia systems5. Some centers suggest a baseline infusion rate with bolus on demand, but the risk of respiratory depression is even higher with this setting. The reason for that practice is mostly to compensate for the limitation of certain pumps with minimal lockout of 5 minutes, which causes insufficient analgesia when the contractions occur every 1 to 2 minutes. The risk of respiratory depression is increased if you combine remifentanil with other medications such as magnesium that can alter the mental status. Con: Additional monitoring and closer observation are required during the therapy. This option requires continuous pulse oximeter, respiratory rate monitoring and PCA pumps that can be programed as needed, as well as a designated nursing staff. There is significant respiratory morbidity with remifentanil IV PCA as periods of apnea occurred even when readings from the pulse oximetry did not show hypoxia (SaO2 <94%). Thus, the pulse oximetry is not a foolproof way of detecting periods of apnea and 1:1 nursing observation may be required6. Unfortunately, the pumps limitation is their minimum lock-out time. It has to be short enough (1-2 minutes) to allow iterative bolus of remifentanil as the contractions get closer one from each other. Otherwise the parturient will experience only partial relief. References J. M. Blair, D. A. Hill, J. P. H. Fee. Patient‐controlled analgesia for labor using remifentanil: a feasibility study. Br. J. Anaesth. (2001) 87 (3):415-420. Stocki D. et al. “A Randomized Controlled Trial of the Efficacy and Respiratory Effects of Patient-Controlled Intravenous Remifentanil Analgesia and Patient-Controlled Epidural Analgesia in Laboring Women.” Anesth Analg 2014; 118:589-97. Additional Case Information At the end of the day, the obstetric resident tells you that the patient was fully dilated and has been pushing for an hour. She is not very optimistic for a successful vaginal delivery because the baby is very big (the estimated fetal weight is 4100g). 9. What additional information would you like to acquire at this point? Do we have a recent set of labs (Coagulation and CBC) Station of the baby and possibility of instrumentation assisted delivery Is the patient type and crossed in case of cesarean delivery and risk of PPH (large baby, PEC, prolonged infusion of oxytocin) Additional Case Information A new set of labs was just sent and the platelets went back up to 110K with INR at 1.3. The baby is doing ok and the plan is to continue trying for vaginal delivery. Unfortunately, after another hour, the OB attending has to call for an emergency cesarean delivery for non-reassuring fetal heart tracing and arrest of descent. You would prefer to do a spinal because of the potential for difficulty securing the airway. 10. List factors that might prevent you from using neuraxial anesthesia at this point. Patient refusal Severe coagulopathy and/or thrombocytopenia Persistent fetal bradycardia and no time for spinal Eclamptic seizure, altered mental status and need to protect the airway Pulmonary edema with desaturation Hemodynamic instability due to bleeding (placental abruption more frequent in PEC) References Henke VG, Bateman BT, Leffert LR. Focused review: spinal anesthesia in severe pre-eclampsia. Anesth Analg 2013 Sep; 117 (3); 686-93. Visalyaputra S, Rodanant O, Somboonviboon W, Tantivitayatan K, Thienthongh S, Saengchote W. Spinal vs epidural anesthesia for cesarean delivery in severe pre-eclampsia: a prospective randomized, multicenter study. Anesth Analg 2005; 101; 862-8. Additional Case Information You decide to do a single shot spinal after explaining all the risks and benefits to your patient. The spinal is successful and the cesarean delivery goes well. Two days later, you visit your patient on the postpartum floor, and she informs you that her right leg has been very weak and she cannot stand up. “It feels like my leg is giving up. Do you think I am having the complications you were telling me about? I am so anxious now…” 11. If you want to rule out an epidural hematoma, what additional features will you look for/ask the patient about? Urinary or rectal incontinence Severe back pain Worsening progression of symptoms No specific dermatomal distribution Mix of both motor and sensory deficits Onset 0-2 days 12. Which of the following is the most likely cause of this patient’s symptoms? a. Epidural hematoma b. Epidural abscess c. Peripheral nerve palsy d. Lumbar herniated disc This patient’s symptoms are most consistent with nerve injury secondary to prolonged pushing with hyperflexion of the hips. This injury is more likely with a large baby compressing the obturator and femoral nerve inside the pelvis. Generally, this complication carries a good prognosis, with total recovery within 6 weeks. Physical therapy is considered first line treatment9. Reference Santos AC, Esptein JN, Chaudhuri K. Obstetric Anesthesia. Peripheral Nerve Injury Associated with Labor. 213-220. Additional Case Information After a few days on the floor, your patient’s neurologic symptoms are improving and she is finally able to walk around but now she says her head hurts a lot and she has blurry vision. She is not very happy and tells you this is “the last pregnancy she will have.” 13. Which of the following is NOT a symptom of PDPH? a. Tinnitus b. Isolated neck stiffness c. Postural headache d. Blurry vision e. Fever The etiology of PDPH is the inadvertent puncture of the dura by the Tuohy needle (but can also be seen after dural puncture with smaller size needles such as 25G). Its diagnosis requires the demonstration of a postural component of the headache or the neck pain/stiffness. It can be associated with other neurologic symptoms such as diplopia or tinnitus, but the presence of fever is not consistent with the diagnosis and should be investigated further. Reference Macarthur, Alison. “Postpartum Headache.” Chestnut’s Obstetric Anesthesia: Principles and Practice. Ed. David H. Chestnut, Cynthia A. Wong, Lawrence C. Tsen, Warwick D. Ngan Kee, Yaakov Beilin, and Jill M. Mhyre. 5th ed. PA: Philadelphia, 2014. 713-738. 14. List other potential etiologies which could be consistent with this presentation and should be included in your differential diagnosis? Elevated blood pressure as a result of ongoing pre-eclampsia Cerebral hemorrhage secondary to elevated BP Cerebral edema Loading …
