Anesthesiology

The Thrombophilic Parturient (e.g., LMWH)

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What the Anesthesiologist Should Know before the Operative Procedure

Pregnancy induces a hypercoagulable state. While the incidence of thromboembolic complications in the peripartum period is low, they remain a major cause of maternal morbidity and mortality. In most cases, the risks associated with administering anticoagulation therapy are greater than those of the hypercoagulable state associated with pregnancy. However, in the presence of an acquired or inherited thrombophilic state, anticoagulation therapy may be indicated.

Inherited or acquired thrombophilic states include:

  • Protein C deficiency

  • Factor V Leiden mutation

  • Protein S deficiency

  • Antithrombin III deficiency

  • Lupus anticoagulant

  • Cardiac valve replacement

  • Malignancy

Furthermore, anticoagulant medications, such as low molecular weight heparin (LMWH), unfractionated heparin (UH), or aspirin, are commonly used for women with a history of fetal loss related to thrombophilia and hypercoagulable syndromes. Low molecular weight heparin has gained widespread use in pregnancy due to many advantages over unfractionated heparin; however, all anticoagulants carry a risk of hemorrhagic complications for the parturient, which will impact clinical decisions from a surgical and anesthetic perspective.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

When possible, delivery should be scheduled (schedule cesarean or induction of labor) for a patient on anticoagulation therapy due to their medication issues and increased risk of venous thromboembolism (VTE) or pulmonary embolism (PE). However, appropriate management of anticoagulation as the peripartum period approaches is essential for providing ideal anesthetic and surgical conditions, and for providing the parturient with the most satisfying labor experience or cesarean delivery.

  • At no later than 36 weeks, any oral anticoagulation therapy or LMWH should be converted to UH to allow rapid testing (PTT) for clearance if labor occurs. UH can also be reversed in an emergency situation.

  • Alternatively, LMWH can be discontinued 24 hours before scheduled induction or cesarean delivery to allow for regional anesthetic options.

  • IV UH should be discontinued 4 to 6 hours prior to induction or cesarean to allow for regional anesthetic options.

Emergent: Anesthetic management will be determined by the proximity of the most recent dose of anticoagulation. If the patient has discontinued anticoagulation therapy for an appropriate period of time, neuraxial anesthesia may be performed when otherwise appropriate.

  • Warfarin - Discontinue 4-5 days prior to planned delivery and document an INR less than 1.2.

  • Unfractionated heparin- 4-6 hours of discontinued use with a documented normal PTT.

  • Low molecular weight heparin- at prophylactic doses, block placement can occur 10-12 hours after the final dose. At therapeutic doses, block placement can occur 24 hours after the final dose has been administered. There is no need to check a PTT, as it is the value of antifactor Xa levels that determine the level of anti-coagulation. In addition, a PTT will probably take too long to return from the lab to be of value in an emergent situation.

  • Aspirin - There is no evidence of increased risk of hemorrhagic complications resulting from neuraxial blockade in patients taking aspirin.

For the patient receiving anticoagulation therapy, the anesthesiologist should be alert for the dangers of hemorrhagic complications in the course of vaginal or cesarean delivery. Finally, attention should be paid to the indication for anticoagulation in anticipation of potential peripartum thrombotic complications. Patients at highest risk of thromboembolic complications are those with acute thromboembolism during the current pregnancy or those with mechanical heart valves - they should be receiving therapeutic anti-coagulation.

Urgent: Anesthetic management will be determined by the proximity of the most recent dose of anticoagulation in conjunction with the risks of delaying delivery. Benefits of postponing delivery in this setting would include the option of neuraxial labor analgesia or anesthesia as well as decreased risk of peripartum hemorrhage. Again, special attention should be paid to the specific indication for anticoagulation, as the risks of suspending anticoagulation may outweigh the risks of its continuation.

Elective: When possible, the patient should appropriately discontinue anticoagulation therapy in anticipation of delivery.

2. Preoperative evaluation

The indication for anticoagulation therapy must be ascertained in order to identify potential risks to the parturient during vaginal or cesarean delivery and the associated anesthetic care stemming from the underlying thrombophilia. The clinician must be aware of a history of VTE in order to watch for a recurrence in the peripartum period following cessation of anticoagulation.

It is essential to ascertain precisely what medication the patient was taking, the dosing regimen (prophylactic or therapeutic), and when anticoagulation was discontinued while also obtaining appropriate laboratory measures of coagulation. INR should be checked in the case of warfarin therapy, and PTT in the case of UH. A platelet count is also necessary in this population, given the possibility of thrombocytopenia from conditions such as heparin induced thrombocytopenia (HIT). The need to follow anti-Xa levels for LMWH dosing is controversial, and the test is not available at all centers.

Delaying delivery to normalize coagulation parameters may be indicated if the benefits of neuraxial anesthesia/analgesia and the lower risk of hemorrhagic complications outweigh risk to the fetus or mother from delaying vaginal or surgical delivery.

3. What are the implications of co-existing disease on perioperative care?

N/A

b. Cardiovascular system

Perioperative evaluation: Besides a history of fetal demise in the setting of thrombophilia, other indications for anticoagulation during pregnancy include increased risk for VTE or PE due to acquired or inherited thrombophilia, a history of VTE or PE especially in the current pregnancy, or mechanical heart valve. Therefore, an initial cardiovascular assessment is critical in the thrombophilic patient.

It is important to identify if the patient is receiving anticoagulation prophylactically or for treatment of a VTE/PE. If the latter, the clinician must identify the current status of the VTE/PE and if there are any functional cardiopulmonary sequelae or existing thromboses with risk of embolization. Furthermore, certain conditions necessitating anticoagulation therapy, such as systemic lupus erythematosus (SLE), present increased risk for coexisting cardiovascular conditions such as pericarditis, valvular abnormalities, or pulmonary hypertension.

Perioperative risk reduction strategies: Be vigilant for the possibility of hemorrhagic complications during delivery, especially when anticoagulation has not been discontinued for an adequate duration. The practitioner should be aware of the patient's preoperative hematocrit, and have blood products available when appropriate. Optimal management of the anticoagulated parturient involves appropriate discontinuation of anticoagulation therapy prior to anticipated delivery as well as prompt resumption of anticoagulation following delivery, when appropriate.

  • Prior to anticipated delivery:

    • At no later than 36 weeks, any oral anticoagulation therapy or LMWH treatment should be converted to UH and a documented INR of less than 1.2 should be obtained in the case of warfarin.

    • Alternatively, LMWH should be discontinued 24 hours prior to anticipated delivery and switched to intravenous UH if necessary.

    • IV UH should be discontinued 4 to 6 hours prior with a normal PTT documented.

  • Following delivery:

    • Anticoagulation should be resumed no sooner than 4-6 hours after vaginal delivery or 6-12 hours after cesarean delivery. Resumption of warfarin should be bridged with the use of LMWH or UH until a therapeutic INR is documented. Compression stockings should be left in place until the patient is ambulatory and until anticoagulation therapy is restarted.

    • Recommendations from the ASRA guidelines are for resumption of prophylactic LMWH no sooner than 2 hours after epidural catheter removal, and for resumption of therapeutic LMWH no sooner than 12 hours after catheter removal.

c. Pulmonary

Perioperative evaluation: If the patient is undergoing anticoagulation due to a history of VTE or PE, the anesthesiologist must be aware of the presence of current thromboses with potential for embolization or existing PE. If PE is present, an assessment of cardiopulmonary status should be made to determine if functional sequelae exist. Furthermore, certain conditions necessitating anticoagulation therapy, such as SLE, present increased risk for coexisting pulmonary conditions, including pneumonitis or pleural effusion.

Perioperative risk reduction strategies: In order to reduce the risk of VTE or PE, strict adherence to appropriate discontinuation and resumption of anticoagulation guidelines must be followed.

  • Prior to anticipated delivery:

    • At no later than 36 weeks, any oral anticoagulation therapy or LMWH should be converted to UH and a documented INR of less than 1.2 should be obtained in the case of warfarin therapy.

    • Alternatively, LMWH should be discontinued 24 hours prior to anticipated delivery and switched to intravenous UH if necessary.

    • IV UH should be discontinued 4 to 6 hours prior to delivery or neuraxial anesthesia placement with a normal PTT is documented.

  • Following delivery:

    • Therapeutic anticoagulation should be resumed 12 hours following delivery or removal of the epidural catheter, whichever occurs last. Resumption of Coumadin should be bridged with the use of LMWH or UH until a therapeutic INR is documented.

d. Renal-GI:

Perioperative evaluation: As thrombophilia secondary to SLE is an indication for anticoagulation therapy during pregnancy, lupus-associated renal disease may be present in the anticoagulated patient with lupus. A creatinine level should be obtained.

Perioperative risk reduction strategies: Document normalization of coagulation parameters when the anticoagulation therapy is renally cleared. LMWH is of particular concern in the renally compromised patient.

e. Neurologic:

Perioperative evaluation: As thrombophilia secondary to SLE is an indication for anticoagulation therapy during pregnancy, lupus-associated neurologic disease may be present in the anticoagulated patient with lupus. Patients with lupus may have central or peripheral sensorimotor or autonomic neuropathies, seizure disorders, or frank psychosis. Furthermore, any neurologic deficits present prior to neuraxial blockade due to any etiology should be well documented prior to neuraxial block placement. If the thrombophilic parturient has had a stroke, document any residual deficits.

Perioperative risk reduction strategies: There are no pertinent considerations regarding neurologic disease as it impacts the anticoagulated thrombophilic parturient.

f. Endocrine:

Perioperative evaluation: As thrombophilia secondary to SLE is an indication for anticoagulation therapy during pregnancy, the anticoagulated patient with lupus may be at risk for adrenal insufficiency due to long term corticosteroid therapy.

Perioperative risk reduction strategies: A peripartum stress dose of corticosteroid should be considered for an anticoagulated patient with lupus undergoing chronic corticosteroid therapy.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

There are no pertinent considerations regarding additional systems/conditions as it impacts the anticoagulated thrombophilic parturient.

4. What are the patient's medications and how should they be managed in the perioperative period?

Optimal management of the anticoagulated parturient involves appropriate discontinuation of anticoagulation therapy prior to anticipated delivery, as well as prompt resumption of anticoagulation following delivery, when appropriate.

  • Prior to anticipated delivery:

    • At no later than 36 weeks, any oral anticoagulation therapy or LMWH should be converted to UH, and a documented INR of less than 1.2 should be obtained in the case of warfarin.

    • Alternatively, LMWH could be discontinued 24 hours prior to anticipated delivery or the need for neuraxial anesthesia and switched to intravenous UH if necessary.

    • IV UH should be discontinued 4 to 6 hours prior with a normal PTT documented.

  • Following delivery:

    • Therapeutic anticoagulation should be resumed 12 hours following delivery or removal of the epidural catheter, whichever occurs last. Prophylactic doses of anticoagulation can be resumed 4-6 hours after vaginal delivery or 2 hours after epidural removal. Resumption of Coumadin should be bridged with the use of LMWH or UH until a therapeutic INR is documented.

All other medications should be managed as usual in regard to the parturient.

h. Are there medications commonly seen in patients undergoing this procedure for which should there be greater concern?

In the setting of an anticoagulated patient taking chronic corticosteroid therapy, a peripartum stress dose of corticosteroid should be considered.

i. What should be recommended with regard to continuation of medications taken chronically?

  • Cardiac: there are no special considerations for the anticoagulated thrombophilic parturient regarding cardiac medications.

  • Pulmonary: there are no special considerations for the anticoagulated thrombophilic parturient regarding pulmonary medications.

  • Renal: there are no special considerations for the anticoagulated thrombophilic parturient regarding renal medications.

  • Neurologic: there are no special considerations for the anticoagulated thrombophilic parturient regarding neurologic medications.

  • Anti-platelet: additional care is needed, as the risk of epidural hematoma is greater in the parturient on anti-platelet medication in conjunction with other anticoagulation therapy. There are no special considerations when anti-platelet therapy is utilized alone.

  • Psychiatric: there are no special considerations for the anticoagulated thrombophilic parturient for psychiatric medications.

j. How To modify care for patients with known allergies -

There are no special considerations for the anticoagulated thrombophilic parturient regarding known allergies.

k. Latex allergy- If the patient has a sensitivity to latex (e.g., rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

There are no special considerations for the anticoagulated thrombophilic parturient for a known latex allergy.

l. Does the patient have any antibiotic allergies- - Common antibiotic allergies and alternative antibiotics]

There are no special considerations for the anticoagulated thrombophilic parturient regarding known antibiotic allergies.

m. Does the patient have a history of allergy to anesthesia?

i. Malignant hyperthermia

  1. Documented- avoid all trigger agents such as succinylcholine and inhalational agents:

    • Proposed general anesthetic plan: There are no special considerations for the anticoagulated thrombophilic parturient for known MH.

    • Insure MH cart available:

ii. Local anesthetics/ muscle relaxants

There are no special considerations for the anticoagulated thrombophilic parturient regarding known reactions to local anesthetics or muscle relaxants.

5. What laboratory tests should be obtained and has everything been reviewed?

Laboratory tests obtained will depend primarily upon the anticoagulation being administered to the thrombophilic parturient and the time that has elapsed since the final dose of anticoagulation. Warfarin requires a PT and INR. UH requires PTT.

LMWH testing is controversial, but the patient may have been followed with antifactor Xa levels during her pregnancy. This test is not available in all centers, and the anesthesia provider may not have results back in time to make clinical decisions. Other laboratory values may be obtained, depending upon the indication for anticoagulation insofar as this condition is associated with potential comorbidities (i.e. cardiopulmonary conditions associated with SLE).

Hemoglobin levels

Given the enhanced potential for hemorrhagic complications in the setting of anticoagulation, a baseline hemoglobin and hematocrit is indicated for the anticoagulated parturient. A complete blood count with platelet count is also indicated, given the potentially compromised clotting ability and the potential for utilization of neuraxial anesthetic techniques.

Furthermore, heparin induced thrombocytopenia (HIT) may be seen during UH or LMWH anticoagulation. It should be noted that platelet counts generally drop by 20% in a normal pregnancy, while approximately 7% of parturients will present with a platelet count of less than 150,000 mm-3 and 0.5 - 1% will present with a count less than 100,000.

While there is no absolute platelet count above which neuraxial anesthesia is considered safe, 100,000 mm-3 has been almost universally acknowledged as acceptable, with many institutions utilizing neuraxial techniques with a count as low as 75,000 if stable. The decision regarding the placement of a neuraxial anesthetic in the setting of a marginal platelet count should be modulated by a consideration of any residual anticoagulation in a parturient undergoing such therapy.

Electrolytes

Electrolytes are indicated with comorbidities that may be associated with the indication for anticoagulation in the parturient. Examples would include cardiopulmonary or renal disorders associated with SLE. Outside of such comorbidities, electrolyte levels would not be necessary in the anticoagulated thrombophilic parturient.

Coagulation panel

Appropriate discontinuation of anticoagulation therapy as previously discussed should be observed. However, in the setting of unfractionated heparin therapy, PTT should be obtained, and in the setting of warfarin therapy, PT/INR should be obtained. There are currently no laboratory tests indicated for the patient on LMWH.

Imaging

Imaging would only be indicated in the setting of comorbid conditions such as cardiopulmonary dysfunction associated with SLE. A spiral CT scan should be obtained for suspected pulmonary embolism.

Other tests

Other tests that may be useful, although not indicated, include platelet function analysis in the setting of aspirin therapy, antifactor Xa levels in the setting of low molecular weight heparin therapy, or a thromboelastogram to assess all phases of coagulation and fibrinolysis. The author does not routinely obtain these tests prior to placement of a neuraxial anesthetic, even in the anticoagulated patient.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

The main considerations for labor analgesia or anesthesia in the thrombophilic parturient are the current status of anticoagulation, including the time since the final dose of anticoagulation, and any laboratory values indicating that clotting function has normalized. There are direct implications on the safety of neuraxial techniques regarding the risk of epidural hematoma.

One must also consider the potential for hemorrhagic complications plus the associated hemodynamic consequences of a general anesthetic if cesarean delivery is performed, however. Cardiopulmonary conditions associated with the underlying disorder requiring anticoagulation (e.g. pulmonary embolism) would also impact the anesthetic technique utilized, and would be considered in addition to the anticoagulation status of the patient.

Neuraxial anesthesia

Neuraxial techniques have long been utilized for labor analgesia and surgical anesthesia in the parturient population. Epidural and spinal techniques have been a mainstay of labor analgesia and anesthesia for years, with many advantages over other regional, intravenous, or general techniques as listed below.

The anticoagulated thrombophilic parturient presents additional considerations when weighing the advantages and risks involved in these techniques. Other regional techniques, such as paracervical block, lumbar sympathetic block, pudendal nerve block, or perineal infiltration, are also available to the patient, and may have some benefit in selected cases.

Neuraxial

Benefits: Epidural techniques provide safe and reliable analgesia, are titratable by the anesthesiologist or patient (with the use of patient controlled anesthesia devices), provide practically unlimited duration of analgesia, and provide the ability to convert to a surgical level if a surgical delivery becomes necessary. Spinal techniques provide a rapid and reliable level of surgical anesthesia while allowing the parturient to be conscious for the birth of her child or children. The combined spinal/epidural technique provides rapid and reliable analgesia as well as all of the previously listed benefits of the epidural technique.

In the setting of a surgical delivery, neuraxial techniques also allow the anesthesiologist to avoid the risks associated with induction of anesthesia and airway management. These are increased in parturients who have a full stomach due to the physiologic changes to the gastrointestinal system associated with pregnancy and associated changes in airway anatomy.

Drawbacks: In any patient population, the decision to utilize a neuraxial technique must take into account the associated risks of epidural hematoma, infection, neurologic injury, and post-dural puncture headache. The low incidence of these risks is usually considered acceptable in the healthy parturient.

Anticoagulation clearly changes this risk-benefit ratio. Careful attention must be paid to the status of anticoagulation by obtaining the appropriate laboratory values, depending on the anticoagulant utilized, as well as a platelet count to minimize the risk of epidural hematoma. Furthermore, given the increased risk of surgical hemorrhage associated with anticoagulation, the sympathectomy caused by neuraxial techniques may limit the ability of a patient to mount a normal cardiovascular response to hypovolemia.

Issues: The following recommendations regarding the safety of neuraxial techniques in the setting of antithrombotic medication therapy are based on the consensus statements of the American Society of Regional Anesthesia (www.ASRA.com). It must be noted, however, that these recommendations are made to respond solely to the risk of epidural hematoma associated with antithrombotics. The clinician must also weigh the risk of hemorrhagic complications associated with impaired clotting, and take into account the sympathectomy associated with neuraxial anesthetics, and whether hemorrhagic complications may be increased.

  • Warfarin- 4-5 days of discontinued use with a documented normal INR are necessary.

  • Unfractionated heparin- 4-6 hours of discontinued use with a documented normal PTT.

  • Low molecular weight heparin- at prophylactic doses, block placement can occur 10-12 hours after the final dose. At higher than prophylactic doses, block placement can occur 24 hours after the final dose has been administered.

  • Aspirin- There is no evidence of increased risk of hemorrhagic complications resulting from neuraxial blockade in patients taking aspirin alone.

Peripheral Nerve Block

Benefits: Techniques such as paracervical block, lumbar sympathetic block, pudendal nerve block, or perineal infiltration are sometimes utilized and provide a more localized area of sensory block without the profound sympathetic and motor block that may be associated with a neuraxial technique. They can also target the discomfort associated with the particular stages of labor.

Drawbacks: Peripheral techniques are generally less effective than neuraxial anesthesia and have a limited field of effect. They are non-titratable, and are administered in a single shot with a limited duration. Also, they only target the discomfort associated with a single stage of labor.

Issues: In general, peripheral techniques are not contraindicated in the setting of anticoagulation; however, the increased risk of hematoma and bleeding should be taken into account. The provider should recognize that in the case of lumbar sympathetic block, trespass into the epidural or spinal space is an associated complication.

General Anesthesia

General anesthesia is always an option for cesarean delivery. However, its use is often avoided due to the benefits of neuraxial techniques and the increased risks of anesthetic induction and airway management in the parturient (aspiration and airway anatomic changes). If a parturient requires a cesarean delivery, and has not discontinued her anticoagulants, then general anesthesia is likely to be the only anesthetic option.

Benefits: The benefits of a general anesthetic include avoidance of neuraxial complications, such as post-dural-puncture headache, neurologic injury, infection, and epidural hematoma. Furthermore, the sympathetic blockade associated with a neuraxial anesthetic utilized for surgical delivery exacerbates hypotension and hypoperfusion associated if peripartum hemorrhage occurs. These are of increased concern in the anticoagulated parturient.

Drawbacks: The drawbacks in the population under consideration are identical to those in all parturients. Induction of anesthesia is associated with increased risk of pulmonary aspiration due to decreased lower esophageal pressure and increased gastric pressures associated with pregnancy. Airway management is complicated by soft tissue changes to the airway anatomy in pregnancy.

Functional residual capacity (FRC) is decreased, while metabolic demands are increased, so desaturation occurs more quickly while securing the airway after apnea is induced. A rapid sequence technique is therefore advised in all parturients undergoing a general anesthesia. Furthermore, the choice of induction and maintenance agent must take into account the increased risk of hemorrhage. Therefore, agents such as etomidate or ketamine may be appropriate, especially if hemorrhage is already occurring, in order to limit decreases in systemic vascular resistance (SVR) or cardiac output.

Monitored Anesthesia Care (MAC)

MAC techniques play a limited role in labor analgesia or anesthesia. Parenteral medication is often utilized by obstetric clinicians, and their use would not be affected by anticoagulation in the thrombophilic parturient. Intravenous PCA with fentanyl or other opioids may be an option for labor analgesia in patients who remain anticoagulated and are not candidates for neuraxial analgesia. Agents associated with histamine release may be of concern in the setting of hemorrhage, because hypotension may be further exacerbated.

6. What is the author's preferred method of anesthesia technique and why?

Neuraxial techniques are superior to any other form of analgesia and are safer than general anesthesia. However, in the setting of anticoagulation for the thrombophilic parturient, the risk benefit calculus is altered. The guidelines regarding the safety of neuraxial techniques in the setting of thrombolytic agents must be observed as follows:

  • Warfarin- 4-5 days since the last dose and a documented normal INR are necessary.

  • Unfractionated heparin- 4-6 hours since the last dose with a documented normal PTT.

  • Low molecular weight heparin- at prophylactic doses, block placement can occur 10-12 hours after the last dose; at therapeutic doses, block placement should not occur until 24 hours after the final dose has been administered. No lab testing is recommended.

  • Aspirin- There is no evidence of increased risk of hemorrhagic complications resulting from neuraxial blockade in patients taking aspirin.

However, pursuing a general anesthetic as opposed to a neuraxial anesthetic may occur for reasons other than not meeting these recommended guidelines. For instance, one must be aware of the increased risk of hemorrhagic complications due to anticoagulation, macrosomia, multiple gestation, multiple repeat cesarean sections, chorioamnionitis, placental abruption, placenta previa, accreta, increta, and percreta. The clinician should check the preoperative hemoglobin and hematocrit, and have appropriate intravenous access and blood products available.

What prophylactic antibiotics should be administered?

The preferred antibiotic therapy consists of cefoxitin or cefazolin 1-2 g IV. If beta-lactam allergy is present, then consult with the obstetric service.

What do I need to know about the surgical technique to optimize my anesthetic care?

In general, a low transverse incision is utilized for cesarean delivery, as it is associated with less post-operative pain, greater wound strength, and better cosmetic results. However, a vertical incision allows for faster abdominal entry, causes less bleeding, and provides the ability to extend the incision cephalad if more exposure is required.

In order to select the appropriate anesthetic technique, the anesthesiologist should be aware if the parturient is having a repeat cesarean delivery, has a history of abdominal surgery which may complicate the cesarean, or has any other condition that may increase the risk of hemorrhage, such as those listed above.

In addition to the increased risk of hemorrhage associated with a more complicated surgical delivery (especially in the setting of anticoagulation), the increased time required for surgical delivery and closure may influence the choice of neuraxial technique. A single bolus spinal anesthetic can reliably provide two to three hours of surgical anesthesia, but if surgical time is longer (in the case of repeat cesarean, prior abdominal surgery, or additional procedures, such as ovarian mass removal), consider a combined spinal/epidural technique or a general anesthetic.

What can I do intraoperatively to assist the surgeon and optimize patient care?

In the case of an emergent surgical delivery, providing surgical anesthesia as safely and quickly as possible is essential. In the setting of anticoagulation in a thrombophilic parturient, adequate IV access with two large bore IV lines is recommended, regardless of the anesthetic technique. An arterial line may be considered, depending on the concern for hemorrhage or if any preexisting cardiac conditions are present, and blood products should be available. Uterotonic agents such as oxytocin, methylergonovine, and carboprost should be available in order to minimize the risk of post-partum hemorrhage, which is increased with the concomitant use of anticoagulants.

What are the most common intraoperative complications and how can they be avoided/treated?

The anesthesiologist must stay most vigilant for hemorrhage in the anticoagulated thrombophilic parturient. The strategies to avoid or minimize this risk include those listed above, as well as recognizing the fact that a neuraxial technique may exacerbate hypotension associated with hemorrhage because of sympathetic block.

Always be prepared for airway complications, especially in the parturient who has increased risk of aspiration, changes in FRC, and altered airway anatomy. With the increased risk of hemorrhagic complications, even if a neuraxial technique has been chosen, the appropriate induction agents and airway equipment for a rapid sequence intubation must be available at all times.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

There are no special criteria for extubation in the anticoagulated thrombophilic parturient.

c. Postoperative management

What analgesic modalities can I implement?

Many postoperative analgesic modalities are available for the parturient. The one chosen will depend on the anesthetic modality utilized, especially following surgical delivery. Furthermore, there are special considerations for the post-operative care of the anticoagulated thrombophilic parturient. If a neuraxial anesthetic is chosen for surgical delivery, preservative-free morphine added to the spinal anesthetic dose can provide up to 24 hours of postoperative analgesia. Doses of 0.1 to 0.25 mg of morphine have been utilized. With higher doses, the analgesia is generally not improved, but the incidence of complications such as pruritus, sedation, and respiratory depression are increased.

If an epidural technique is utilized for surgical delivery, preservative-free morphine can be placed in the epidural space and provide post-operative analgesia similar to intrathecal morphine. The doses commonly utilized range between 3 and 5 mg. Any postpartum mother who has received intrathecal or epidural morphine should have 24 hours of monitored care due to the associated risk of respiratory depression. Oral agents, such as acetaminophen/oxycodone, are also commonly utilized in addition to intrathecal or epidural morphine.

In situations where intrathecal or epidural morphine is not utilized, IV narcotics are commonly administered as a patient-controlled technique with demand doses available. A variety of narcotic agents (fentanyl, morphine, hydromorphone) are commonly utilized. The choice of agent will depend on the institution or the individual patient response to particular narcotics. IV NSAIDS such as ketorolac are very commonly utilized as an adjunct to narcotic analgesia, but should be avoided in the anticoagulated thrombophilic parturient already at increased risk of post-operative hemorrhage.

Transversus abdominus plane (TAP) blocks have been used after cesarean delivery with reports of success. In the setting of an indwelling epidural catheter, anticoagulation should not be resumed until 12 hours following delivery or removal of the epidural catheter, whichever occurs last. The anesthesiologist and obstetrician must be in communication about the timing of epidural catheter removal and resumption of anticoagulation.

What level bed acuity is appropriate?

If the parturient had severe hemorrhage necessitating large volume fluid and blood product resuscitation, ICU or step down care would be appropriate. Outside of complications associated with delivery, however, no special post-operative monitoring is indicated.

If the patient has received intrathecal or epidural morphine, monitored care, especially for respiratory complications, is required for 24 hours due to risk of respiratory depression. The ASA guidelines for monitoring should be followed. How these guidelines are met will be institution-dependent, ranging from normal post-surgical unit care with hourly respiratory monitoring to step-down care.

What are common postoperative complications, and ways to prevent and treat them?

In the setting of anticoagulation, especially if delivery (vaginal or surgical) has occurred without the recommended cessation of anticoagulation, hemorrhage is the most concerning potential post-operative complication. Preventing hemorrhage is achieved through avoidance of exacerbating agents and appropriate timing for resumption of anticoagulation. In the thrombophilic population, thrombotic complications must be at the fore of the providers mind, and anticoagulation should be resumed 12 hours following delivery or removal of the epidural catheter, when indicated.

What's the Evidence?

"ACOG Committee on Practice Bulletins. #124 Inherited thrombophilias in pregnancy". Obstet Gynecol. vol. 118. 2011. pp. 730-9.

(ACOG's practice guidelines on management of thrombophilias during pregnancy.)

"ACOG Committee on Practice Bulletins. #123 Thromboembolism in pregnancy". Obstet Gynecol. vol. 118. 2011. pp. 718-28.

(ACOG's practice guidelines on diagnosis and management of thrombosis and embolism during pregnancy.)

Bates, SM, Greer, IA, Papinger, L. "Venous thromboembolism, thrombophilia, antithrombotic therapy, and pregnancy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines". Chest. vol. 133. 2008. pp. 844S.

(Practice guidelines for management in the non-pregnant patient, including discussions of various medications.)

Horlocker, TT, Wedel, DJ, Rowlingson, JC. "Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine evidence-based guidelines". Reg Anesth Pain Med. vol. 35. 2010. pp. 64-101.

(ASRA guidelines for the use of regional anesthesia when the patient is anti-coagulated.)

Alexander, A, Vitin, Gregory Dembo, Youri Vater, Kenneth Martay, Leonard Azamfirei, Tiberiu Ezri. "Anesthetic implications of the new anticoagulant and antiplatelet drugs". J Clin Anesth. vol. 20. 2008. pp. 228-37.

(Discusses newer anti-coagulants we may see our patients taking, although many will not be used in pregnancy.)

Kopp, SL, Horlocker, TT. "Anticoagulation in Pregnancy and Neuraxial Blocks". Anesthesiology Clinics. vol. 26. 2008. pp. 1-22.

(Good review of the topic, including the ASRA guidelines.)

Chestnut, M.D, Linda, S, Polley, M.D, Lawrence, C, Tsen, M.D, Cynthia, A, Wong, M.D. "Chestnut's Obstetric Anesthesia: Principals and Practice". Mosby Elsevier. 2009.

(Good textbook review of the topic.)

Butwick, AJ, Carvalho, B. "Neuraxial anesthesia in obstetric patients receiving anticoagulant and antithrombotic drugs". Int J Obstet Anesth. vol. 19. 2010. pp. 193-201.

(Review of guidelines related to neuraxial anesthesia in anti-coagulated obstetric patients.)
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