Paula C. Brady1 and Julianna Schantz-Dunn1
(1)
Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women’s Hospital, Boston, MA, USA
Paula C. Brady (Corresponding author)
Email: Pbrady2@partners.org
Julianna Schantz-Dunn
Email: Jschantz-dunn@partners.org
Keywords
Surgical riskAntibiotic prophylaxisThromboprophylaxisAnticoagulation reversalTransfusion
Definition
Emergent Surgery
Typically scheduled within 6 h [1]. In gynecology, emergent operative cases usually involve ovarian torsion, intra-abdominal hemorrhage , severe intra-abdominal infection, intrauterine infection, or vaginal hemorrhage. Urgent surgery is typically scheduled within 6–24 h.
Surgical Risk
Medical conditions conferring increased risk of surgically related severe complications and mortality include diabetes, hypertension, malignancy, prior cardiac events or congestive heart failure, severe chronic obstructive pulmonary disease (COPD), current smoking, dialysis and/or renal failure, and obesity. The presence and severity of these conditions should be considered when determining whether a surgical case should be scheduled emergently or can be delayed to provide time for medical optimization. The American College of Surgeons incorporates these factors into a risk calculator, providing estimated risks of cardiac, thromboembolic, renal, and infectious complications and death; the calculator is available at http://riskcalculator.facs.org [2].
Many grading systems have attempted to quantify the risk of adverse cardiac events, specifically related to surgery. Intraperitoneal surgeries are classified as intermediate risk, with reported risk of cardiac death or nonfatal myocardial infarction of 1–5 %, while endoscopic, superficial, or ambulatory surgery is generally associated with a cardiac risk of less than 1 % [3]. Emergency surgeries generally carry higher risk of adverse events. Particularly high-risk cardiac conditions, which will result in the delay or cancellation of nonemergent cases, include unstable coronary syndromes, decompensated heart failure, significant arrhythmias (including high-grade atrioventricular block, new or symptomatic ventricular arrhythmias, supraventricular arrhythmias with a heart rate greater than 100 beats per minute, and symptomatic bradycardia), and severe aortic or mitral stenosis [3].
Careful consideration should also be given to surgical planning in obese patients. Moderately obese patients (class II obesity or body mass index (BMI) greater than 35 kg/m2) have a higher risk of surgical complications, venous thromboembolism, and wound infections than their normal weight counterparts [4]. Similar to normal weight patients, obese patients have improved outcomes with minimally invasive surgery. Minimally invasive surgery, however, comes with its own set of challenges in the obese patient. Positioning and retracting as part of vaginal surgery may be difficult, while ventilating a morbidly obese patient while in Trendelenburg position can be challenging [5]. Consider asking the operating room to prepare long instruments and trocars, and a bariatric bed and stirrups, as needed.
In patients with these medical conditions, medicine consult should be obtained for clearance. The anesthesia team should also be contacted as soon as possible to discuss the patient’s current condition and medical history.
Preoperative Testing
The vast majority of gynecology patients requiring urgent or emergent surgery will have had a complete blood count collected as part of their assessment. A complete blood count should be collected in any patient with active bleeding, anemia, chronic illness, or a high likelihood of blood loss at the time of surgery [6].
A basic metabolic panel, including serum creatinine, is not routinely recommended but should be collected in patients with chronic illness or taking medications that predispose to electrolyte abnormalities or renal dysfunction, including diuretics, digoxin, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers [4]. A blood type and antibody screen should be collected in all pregnant patients, patients with preoperative anemia, ongoing bleeding, or those who will undergo surgery with moderate to high risk of bleeding, such as resection of an ectopic pregnancy [7]. Coagulation testing (prothrombin time (PT) and activated partial thromboplastin time (aPTT)) is only strictly indicated in patients receiving anticoagulation, those with a history of bleeding after procedures, or with coagulation abnormalities, such as coagulation factor deficiencies, von Willebrand disease, liver disease, and disseminated intravascular coagulation [4]. A pregnancy test should be checked in any woman who is not yet postmenopausal [8].
A 12-lead electrocardiogram (ECG) is recommended for patients with known coronary artery disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease, or other significant structural heart diseases [1]. Routine screening ECGs can also be considered in asymptomatic patients, particularly over age 50 years, undergoing intermediate- or high-risk surgery [9].
Chest radiograph may be considered in patients who smoke or those with recent upper respiratory tract infections, known chronic obstructive pulmonary disease (COPD), or cardiac disease, though radiographs are not strictly required in patients with stable COPD or cardiac disease or resolved respiratory infection [6]. The American Heart Association suggests obtaining chest radiographs in patients with significant obesity (BMI greater than 40 kg/m2) [10].
Consent
The consent process involves discussing the risks, benefits, and alternatives of the planned procedure. The discussion of the management options should include medical, surgical, and expectant management. Include all possible procedures on the consent form, such as ovarian cystectomy and unilateral salpingo-oophorectomy for a patient scheduled for a diagnostic laparoscopy for suspected ovarian torsion. In addition, for diagnostic laparoscopies, include the possibility of a negative laparoscopy (the absence of identifiable pathology). Always include a provision for reparative surgery in the event of iatrogenic injury. During the consent process, specify whether the patient is willing to accept blood products.
Medicaid laws require that federally insured women undergoing hysterectomy or other procedures resulting in sterility sign a sterilization or hysterectomy consent form prior to the procedure. Typically these consents require a 30-day waiting period, though exceptions are made in cases of emergency abdominal surgery. State-specific forms can be found online or on the Department of Health and Human Services website at http://www.hhs.gov/opa/pdfs/consent-for-sterilization-english-updated.pdf. If time allows, the patient should also complete a health care proxy form.
Antibiotic Prophylaxis
For reference, most gynecologic operative cases are considered “clean” or “clean-contaminated,” which is defined as controlled entry into the gastrointestinal, genital, or urinary tract [11]. “Contaminated” cases involve accidental wounds, major breaks in sterile technique, spillage of gastrointestinal contents, or presence of acute nonpurulent inflammation. “Dirty” cases are those involving clinical infection, perforated viscera. Recommended antibiotic prophylaxis, to be given immediately preoperatively, is shown in Table 13.1 [12].
Table 13.1
Recommended antibiotic prophylaxis
|
Procedure |
Antibiotics |
|
Hysterectomy Urogynecology procedures, including mesh placement |
Cefazolin 1–3 g IV (weight based) • Clindamycin 600 mg IV plus gentamicin 1.5 mg/kg IV or quinolone (ciprofloxacin, levofloxacin, moxifloxacin) 400 mg IV or aztreonam 1 g IV • Metronidazole 500 mg IV plus gentamicin 1.5 mg/kg IV or quinolone 400 mg IV |
|
Dilation and evacuation of pregnancy |
• Doxycycline 200 mg PO or IV • Azithromycin 1 g PO or IV plus metronidazole 500 mg PO or IV |
|
Laparoscopy |
None |
|
Laparotomy |
None |
|
Hysteroscopy |
None |
|
IUD insertion |
None |
|
Endometrial biopsy |
None |
American College of Obstetricians and Gynecologists [12]
Please see Chap. 8, Spontaneous Abortion, for more information on antibiotic prophylaxis for dilation and evacuation.
Multiple studies have demonstrated a reduction in vaginal cuff complications in women with bacterial vaginosis (BV) who were treated preoperatively with metronidazole. While urgent surgery may not afford the ideal preoperative treatment time of 5–7 days, a dose of metronidazole (500 milligrams (mg) IV) preoperatively in women with current BV is an option [13].
Thromboprophylaxis
Risk factors for venous thromboembolism include but are not limited to increasing age, immobility, sepsis, malignancy, pregnant or postpartum state, use of estrogen-containing medications or selective estrogen receptor modulators, respiratory failure, inflammatory bowel disease, nephrotic syndrome, indwelling venous catheters, varicose veins, obesity, and smoking [14, 15]. Cardiovascular issues placing patients at high risk of thromboembolism include artificial cardiac valves, prior stroke, transient ischemic attack or venous thromboembolism, thrombophilias (including factor V Leiden, prothrombin variant 20210A, antiphospholipid antibodies, deficiency of antithrombin, protein C, or protein S) and other hematologic abnormalities including heparin-induced thrombocytopenia and myeloproliferative disorders such as polycythemia vera [16, 17].
According to the American College of Obstetricians and Gynecologists, surgeries that are low risk for thromboembolism are defined as those lasting less than 30 min, in patients 40 years of age or less without additional risk factors; these patients do not require additional thromboprophylaxis beyond early ambulation postoperatively [15]. Sequential compression boots should be placed at the time of surgery for all other patients, except on an extremity with known deep vein thrombosis, due to theoretical risk of embolism [18]. For the highest-risk patients, particularly those with active malignancy, hypercoagulable state, or prior thromboembolism, a single dose of heparin 5000 units can be given subcutaneously preoperatively, which has not been associated with additional blood loss intraoperatively [19].
For patients admitted to the hospital after surgery, thromboprophylaxis should be continued postoperatively and should be decided by the surgical team based on the patient’s risks of thromboembolism and postoperative bleeding. Postoperative thromboprophylaxis can include sequential compression boots, heparin (5,000 units subcutaneously every 8–12 h), dalteparin (2500–5000 units subcutaneously daily), or enoxaparin (40 mg subcutaneously daily) [15]. Unfractionated heparin is preferable to dalteparin and enoxaparin in patients with renal insufficiency. Pharmacologic thromboprophylaxis can typically start 12 h postoperatively; the anesthesiologist should be involved in this decision making for patients receiving neuraxial anesthesia, which may require withholding anticoagulation (particularly for epidural catheter removal).
Anticoagulation Reversal
In patients requiring urgent or emergent surgery—particularly intra-abdominal surgery—while anticoagulated, reversal of their anticoagulation medications is usually necessary to minimize intraoperative bleeding. The risk of intraoperative bleeding, however, must be balanced against thromboembolic risk, ideally in consultation with the patient’s hematologist or cardiologist.
Warfarin can be reversed with administration of vitamin K (5–10 mg IV), fresh frozen plasma or prothrombin complex concentrates with a target INR of 1.5 or less [20]. Prothrombin complex concentrates (such as Kcentra®, CSL Behring GmbH, King of Prussia, PA) confer the advantages of rapid infusion and no need for thawing, but are reserved for life-threatening hemorrhage due to elevated risk of thromboembolism [21]. For the oral direct thrombin inhibitor, dabigatran, the only antidote is a monoclonal antibody called idarucizumab that can be administered in 2 doses of 2.5 g IV each, given 15 mins apart [22]. No antidotes exist for the factor Xa inhibitors (rivaroxaban, apixaban, and edoxaban); antifibrinolytic medications (such as tranexamic acid) can be used in patients with active bleeding, while prothrombin complex concentrates are reserved for refractory severe hemorrhage, due to increased risk of thromboembolism [23].
Unfractionated heparin has a short half-life, (approximately 60 mins) but if necessary, 1 mg of protamine sulfate will reverse 100 units of heparin [24]. Low molecular weight heparin (LMWH) is incompletely reversed with protamine sulfate, but for clinically significant bleeding or high risk of intraoperative bleeding in the setting of LMWH given within the past 8 h, 1 mg protamine sulfate can be given for each milligram of enoxaparin. Less protamine sulfate is needed if the LMWH was given more than 8 h prior [21]. If necessary, residual anticoagulant activity can be assessed by checking an aPTT in patients who received unfractionated heparin, while an anti-Xa level will reflect LMWH activity. Please refer to 13.2 for more information.
Table 13.2
Emergent anticoagulation reversal
|
Medication |
Mechanism of action |
Laboratory monitoring |
Half-life in healthy individuals |
Antidote |
Antidote dose |
Side effects of antidote (including, not limited to) |
|
Warfarin |
Blocks hepatic synthesis of vitamin K-dependent clotting factors (II, VII, IX, X) |
PT, INR |
Varies (mean 40 h) |
Vitamin K |
5–10 mg IV |
Hypersensitivity |
|
Fresh frozen plasma (FFP) |
Depends on starting INR |
Infection Febrile or allergic reaction Volume overload |
||||
|
For life-threatening bleeding: prothrombin complex concentrates, such as Kcentra® (CSL Behring GmbH, King of Prussia, PA), containing factors II, VII, IX, X, protein C and S |
Kcentra®: INR 2 to <4: 25 units/kg, max 2500 units INR 4–6: 35 units/kg, max 3500 units INR >6: 50 units/kg, max 5000 units |
Hypersensitivity Thromboembolism (similar to FFP, 3–4 %) May contain heparin; contraindicated in patients with heparin-induced thrombocytopenia |
||||
|
Dabigatran |
Direct thrombin inhibitor |
None, though aPTT may be elevated |
12–17 h |
Oral charcoal if taken in the last 2 h, or dialysis Idarucizumab for severe hemorrhage |
5 g IV (two 2.5 g doses 15 min apart) |
Hypersensitivity Rebound elevation in coagulation parameters (in as little as 1–4 h) Thromboembolism Use with care in hereditary fructose intolerance |
|
Rivaroxaban, apixaban, edoxaban |
Factor Xa inhibitor |
None routinely, though Anti-Xa can be checked |
Rivaroxaban (5–9 h, prolonged to 11–13 h in elderly) Apixaban (11.5 h) Edoxaban (10–14 h) |
None – Oral activated charcoal if medication taken in the last 2 h – Consider antifibrinolytic medications (such as tranexamic acid or aminocaproic acid). Little data and off-label, but risks are low – For life-threatening ongoing hemorrhage despite transfusion and antifibrinolytic medication, can consider prothrombin complex concentrates (off-label) |
Tranexamic acid: 10 mg/kg up to 1 g, or 1 g presumptively |
Adjust for renal impairment Color vision change, visual loss Thromboembolism (controversial, use with caution)Contraindicated in DIC and subarachnoid hemorrhage |
|
Unfractionated heparin |
Potentiates antithrombin activity (inhibiting Xa and thrombin) |
aPTT and/or anti-Xa |
Variable IV: 30–60 min (longer for larger loading doses) Subcutaneous: 1–2 h |
Protamine sulfate (PS) |
Maximum 50 mg Heparin <30 min prior: 1 mg PS per 100 units of heparin Heparin 30 min – 2 h prior: 0.5–0.75 mg PS per 100 units of heparin Heparin >2 h prior: 0.25 mg PS per 100 units of heparin Continuous IV heparin: calculate PS dose based on cumulative heparin dose given in last 2–3 h |
Hypersensitivity/anaphylaxis, particularly in patients with severe fish allergy or diabetics with prior exposure to protamine-containing insulin (NPH) Heparin “rebound” may occur, and repeat PS dosing may be required in 2–4 h |
|
Low molecular weight heparin (enoxaparin, dalteparin) |
Potentiates antithrombin activity (inhibiting Xa and thrombin to a lesser extent) |
None routinely, though Anti-Xa can be checked |
Subcutaneous enoxaparin (4.5 h) Subcutaneous dalteparin (3–5 h) |
Protamine sulfate (PS) provides incomplete neutralization (off-label) |
Maximum 50 mg Enoxaparin <8 h prior: 1 mg PS per 1 mg enoxaparin Enoxaparin ≥8 h prior: 0.5 g PS per 1 mg enoxaparin Dalteparin: 1 mg PS per 100 anti-Xa units of dalteparin |
Hypersensitivity/anaphylaxis, particularly in patients with severe fish allergy or diabetics with prior exposure to protamine-containing insulin (NPH) Heparin “rebound” may occur, and repeat PS dosing may be required in 2–4 h |
Citations are provided in the text
Please see Chap. 2, Vaginal Hemorrhage, for the management of bleeding attributed to coagulation disorders, including disseminated intravascular coagulation and von Willebrand disease.
Resuscitation and Blood Products
For patients with active bleeding that will be managed surgically, active resuscitation should begin while preparing to proceed to surgery. Crystalloids, such as normal saline and lactated Ringer’s solution, are used as first line for maintaining hemodynamic stability, but each additional liter of crystalloid transfused will further dilute the concentration of packed red blood cells—thereby lowering oxygen-carrying capacity to target tissues—and coagulation factors.
In patients with hemorrhagic shock who are too unstable to wait for cross-matched products, the use of emergency release O-negative blood is recommended. Please refer to Chap. 1, Acute Pelvic Pain, for more information on the diagnosis of hemorrhagic shock [25]. In rare cases of gynecology patients requiring massive transfusion, recommendations extrapolated from the trauma literature include a 1:1:1 transfusion ratio of packed red blood cells , fresh frozen plasma, and platelets, meaning 6 units of pooled random donor platelets (which equals one apheresis platelet unit) should be given for every 6 units of red blood cells and 6 units fresh frozen plasma [26–28].
Complications of blood transfusions include hemolytic and non-hemolytic (immune-mediated) reactions, sepsis, Transfusion-Associated Circulatory Overload (TACO) and Transfusion-Related Acute Lung Injury (TRALI). TACO and TRALI are discussed in Chap. 15, High-Acuity Postoperative and Inpatient Issues. In general, if an acute reaction to a blood product is suspected (particularly in patients with acute fever, flank pain and hypotension), the infusion should be stopped, followed by IV hydration, confirmation of patient and blood product identifiers, and blood bank notification.
Most hemorrhage encountered in gynecologic patients can be managed in a goal-oriented manner. Resuscitation goals include hemoglobin of at least 7 g per deciliter (dL), platelets above 50,000 per microliter (μL), fibrinogen above 100 mg/dL, and an INR less than 1.5 [29–32]. Blood products and their effects on laboratory parameters are shown in Table 13.3. The patient’s blood pH and electrolytes (particularly calcium and potassium) should be closely monitored in the setting of multiple transfusions.
Table 13.3
Blood products
|
Blood product |
Lab indicator |
Contains |
Typical effect |
|
Packed red blood cells (PRBC) |
Hemoglobin below 7 g/dL or hematocrit below 21 % |
Packed red cells |
1 unit will raise hemoglobin by 1 g/dL or hematocrit by 3 % |
|
Platelets |
Platelets below 50,000/μL |
Platelets |
1 apheresis unit of platelets (usually a 6 pack of pooled donor platelets) will raise platelets by 30,000–50,000 |
|
Fresh frozen plasma (FFP) |
INR above 1.5 |
All clotting factors and 500 mg of fibrinogen |
Use of FFP (may require multiple units) will correct an INR to 1.3 at best |
|
Cryoprecipitate |
Fibrinogen below 100 mg/dL |
1 bag (five units) contains 1000 mg fibrinogen as well as factor VIII, factor XIII, and von Willebrand factor |
Will raise fibrinogen approximately 40 mg/dL |
|
Fibrinogen concentrate (available commercially in the United States as RiaSTAP®, CSL Behring GmbH, King of Prussia, PA) |
Fibrinogen below 100 mg/dL |
1 vial (mixed in 50 cc sterile water) contains 900–1300 mg of fibrinogen |
Will raise fibrinogen approximately 40 mg/dL |
Santoso et al. [42], Arya et al. [43], Sharma et al. [29], Bell et al. [44]
Certain physiologic goals of resuscitation can also be observed. A patient’s goal heart rate should generally be less than 100 beats per minute, with urine output at least 0.5 mL per kilogram per hour. Maintaining a normal core temperature is also vital to resuscitation; patients who are hypothermic will have impaired coagulation [33]. Removing wet blankets or towels and using fluid warmers and warming blankets can help maintain a safe core temperature.
In addition to allogeneic blood transfusion, consideration should be given to autologous blood transfusion, which can be accomplished with intraoperative blood salvage; Cell Saver® (Haemonetics Corporation, Braintree, MA) is one such device. Intraoperative blood salvage requires coordination with a perfusionist. Advantages to autologous blood transfusion include avoiding allogeneic blood transfusion—and associated reactions and infections—as well as decreased time to prepare blood products [34]. Blood salvage is contraindicated in cases with bacterial contamination or malignancy. Pregnancy is not a contraindication, and studies have demonstrated the benefit of autologous blood transfusion in the setting of ruptured ectopic pregnancies [35, 36].
As an adjunct to treatment of acute bleeding, intravenous tranexamic acid, an antifibrinolytic medication, can be used to reduce blood loss. Tranexamic acid is administered in a dose of 10 mg/kg for a maximum of 1 g, or 1 g presumptively (extrapolating from the trauma literature) intravenously over 10 min and repeated every 8 h as needed [37–40]. Contraindications of tranexamic acid include, but are not limited to, acquired defective color vision and active intravascular clotting. The risk of thromboembolism associated with tranexamic acid is controversial; overall, this medication should be used with caution in patients at high risk for thromboembolism, including those with known thrombophilia or a history of venous thromboembolism [41]. Dosing should be adjusted in patients with renal dysfunction.
Aminocaproic acid is another anti-fibrinolytic medication that can be used instead of tranexamic acid; aminocaproic acid is given as 4–5 g IV (in 250 mL of diluent over 1 h), then 1 g IV per hour until bleeding is controlled [38, 45, 46]. Studies have also reported using desmopressin in cases of severe hemorrhage; desmopressin (0.3 µg/kg subcutaneously or IV) is typically given in the setting of platelet dysfunction or type I von Willebrand disease. Though data are lacking, it is sometimes given as adjunct treatment to enhance platelet function in the setting of hemorrhage, as the risk of thromboembolism has been shown to be low; side effects include vasoconstriction [40, 46].
In cases of life-threatening hemorrhage in patients taking warfarin or oral direct anticoagulants who have failed more conservative measures, prothrombin complex concentrates such as Kcentra® (CSL Behring GmbH, King of Prussia, PA) have been used [46, 47]. Prothrombin complex concentrates are contraindicated in patients with DIC and heparin-induced thrombocytopenia. The risk of thrombosis with prothrombin complex concentrates has been shown to be similar to the risk with FFP (3–4 %) [47]. This thromboembolism risk likely also reflects the underlying condition requiring anticoagulation.
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