Ortho Lipp Flashcards
- The surgeon is performing a right total knee arthroplasty under a combined spinal–epidural anesthetic. The surgical team is providing you with information that within the next 15 minutes they plan to place bone cement (polymethylmethacrylate) to anchor the prosthesis. The most likely clinical side effect that may occur is
A. Hypertension
B. Increased work of breathing and hypercapnia
C. Cardiac arrhythmias
D. Decreased pulmonary shunt
C. Placement of bone cement (bone cement implantation syndrome) can result in any combination of adverse events including hypoxia, hypotension, cardiac arrhythmias (possibly heart block or even sinus arrest), pulmonary hypertension, and decreased cardiac output.
- Potential complications of use of a pneumatic tourniquet include all of the following, except
A. Tourniquet pain that is relieved by performing a peripheral nerve block
B. A compression nerve injury
C. Development ofarterial thromboembolism
D. Pulmonary embolism
A. Use of a compression tourniquet on upper and lower extremities can facilitate surgery and decrease blood loss, but it can result in complications and cannot be applied for prolongedperiods. Use of such devices can be associated with ischemic pain that is not typically or completely relieved by performing peripheral nerve blocks of the extremity. Metabolic alterations upon tourniquet release, arterial thromboembolism, and pulmonary embolism are other potential complications.
- A 20-year-old male (status post car accident) sustained a right femur and pelvic fracture 2 days prior. In the last 24 hours, he has become progressively more short of breath, requiring 100% F IO 2 to maintain an oxygen saturation in the high 80s and is now becoming more confused and disoriented. Physical exam reveals petechiae on the anterior chest wall, arms, and conjunctiva along with decreased breath sounds to auscultation. The most likely diagnosis is
A. Cognitive dysfunction
B. Pulmonary fat embolism
C. Undiagnosed pneumothorax
D. Congestive heart failure
B. A
○ venous fat embolism will typically present itself within 72 hours following long-bone and/or pelvic fracture injuries.
○ Such a condition may also occur following cardiopulmonary resuscitation, parental feeding with lipid infusion, and liposuction surgery.
○ The classical triad includes dyspnea, confusion, and petechiae.
- Incorrect statement regarding neuraxial anesthesia and deep-vein thrombosis/pulmonary embolism (DVT/PE) in orthopedic surgical procedures is
A. Neuraxial anesthesia may reduce thromboembolic complications
B. Neuraxial anesthesia may reduce blood loss
C. Neuraxial anesthesia may decrease platelet reactivity
D. Neuraxial anesthesia may increase activity of both factor VIII and von Willebrand factor
D.
○ Advantages of neuraxial anesthesia in orthopedic surgery may include reduced incidence of DVT and PE formation, decreased platelet activity, decreased factor VIII and von Willebrand factor activity, and attenuation of stress hormone responses.
On postoperative day 1, an orthopedic surgeon has consulted you about his total knee arthroplasty patient who is in severe pain and has failed a regimen of patient-controlled analgesia using morphine. He is now consulting you for an epidural catheter placement for postoperative pain control, and would like to know for what time interval once-daily prophylactic low-molecular-weight heparin (LMWH) should be held prioto performing the epidural procedure:
A. 4 hours and no absolute contraindication to placement of a catheter
B. 6 hours and a relative contraindication to place a catheter
C. 12 hours and no absolute contraindication to placement of a catheter
D. 24 hours and absolute contraindication to place a catheter
- C. For patients receiving once-daily dosage of LMWH for prophylaxis, both epidural and spinal neuraxial techniques may be performed (or neuraxial catheters placed or removed) 10 to 12 hours following the previous dose of LMWH. In addition, a 4-hour time delay should occur before administering the next dose of daily prophylactic LMWH.
- In the anesthesia preadmission testing clinic, you are assessing a 58-year-old female with a medical history significant for hypertension, diabetes,fibromyalgia, and rheumatoid arthritis (RA). The RA is affecting the upper extremities bilaterally and the cervical spine, but her RA symptoms are well-controlled with methotrexate. She is now presenting for an elective total hip arthroplasty. The radiographs that should be ordered to rule out atlantoaxial instability are
A. Lateral view: flexion of the cervical spine
B. Lateral view: extension of the cervical spine
C. No radiographs are indicated since the patient is asymptomatic
D. Lateral view: both flexion and extension of the cervical spine
- D. Advanced RA can affect the cervical spine such that patients may require treatment including steroids, immune therapy, and/or methotrexate. Radiographs of both flexion and extension with lateral views of the cervical spine are
You were involved in a complicated left lower leg procedure (open reduced internal fixation of proximal tibia–fibula fracture repair), where the final total tourniquet time was 3 hours 15 minutes. In the postanesthesia care unit, the patient showed no signs of any peripheral nerve injury of the left lower extremity. However, on postoperative day 2, you discovered that the patient required hemodialysis secondary to rhabdomyolysis. Which of the following could be responsiblefor the rhabdomyolysis?
A. Compartment syndrome
B. Prolonged tourniquet inflation time
C. Statin medication use that patient started 2 weeks prior
D. All of the above
D. Any form of muscle damage of sufficient severity can cause rhabdomyolysis.
○ Multiple causes can be present simultaneously in one individual.
○ Some patients may have an underlying muscle condition, usuallyhereditary in nature, which may make them more prone to rhabdomyolysis.
○ Rhabdomyolysis can be induced by several conditions including compartment syndrome, prolonged tourniquet inflation time, medications such as statins, and malignant hyperthermia.
○ It is suggested that tourniquet times usually be kept to 2 hours or less to decrease the risk of nerve injury, ischemia, and rhabdomyolysis, which could lead to renal failure.
- Concurrent administration of all of the following anticoagulants and thrombolytic therapy should be avoided when planning for neuraxial blockade, except for
A. Fibrinolytic and thrombolytic therapy
B. Thrombin inhibitors (desirudin,lepirudin, bivalirudin, and Argatroban)
C. Therapeutic dosing of low-molecular-weight heparin (LMWH)
D. Subcutaneous heparin daily dose of 10,000 U or less
D. According to the American Society of Regional Anesthesia andPain Medicine anticoagulation guidelines, medications such as antiplatelet agents (Plavix, and intravenous glycoprotein IIb/IIIa inhibitors), thrombolytics, fondaparinux, direct thrombin inhibitors, or therapeutic LMWH present an unacceptable risk for spinal and/or epidural hematoma development without sufficient time lapse between administration of such medications and neuraxial techniques. Maximum administration of subcutaneous heparin of 5,000 U bid is estimated to be safe with epidural and spinal anesthesia.
Heparin administration of 5,000 U tid is not known to be accepted in clinical practice in conjunction with neuraxial blockade.
- The most correct statement regarding blood loss that may occur in a patient with a hip fracture is
A. Intertrochanteric > base of femoral neck > subcapital
B. Transcervical > base of femoral neck > subcapital
C. Subtrochanteric > subcapital > transcervical
D. Subcapital > base of femoral neck > transcervical
A. Blood loss in a patient secondary to a hip fracture can be significant, and some anesthesiologists plan to utilize cell savers and/or perform hypotensive techniques to minimize further blood loss. Blood loss from a hip fracture depends on the actual location of the fracture. As a general rule, intracapsular (subcapital, transcervical) fractures have been associated with less blood loss than extracapsular (base of the femoral neck, intertrochanteric, subtrochanteric) fractures, as the capsule decreases blood loss by acting like a tourniquet. In general, blood loss from a subtrochanteric and intertrochanteric > base of femoral neck > transcervical and subcapital.
A 76-year-old female is to undergo a right femoral neck fracture repair. You perform a spinal anesthetic using 1.5 mL 0.5% bupivacaine mixed with 100 μg of preservative-free morphine. How long should the patient be monitored for postoperative apnea/hypoventilation secondary to the intrathecal morphine administration?
A. 3 days
B. 48 hours
C. 12 hours
D. 24 hours
D. Intrathecal morphine can depress ventilation and CO 2 responsiveness that can last for up to 24 hours. The first peak effect occurs about 6 to 8 hours post injection, and the second peak could happen as late as 24 hours later. The physiologic and pharmacologic mechanisms of this include vascular opioid uptake by the epidural or subarachnoid venous plexuses, rostral spread of the aqueous cerebrospinal fluid to the brainstem, and/or direct perimedullary vascular channels.
A 56-year-old female with medical history significant for obesity (BMI 50), hypertension, diabetes (IDDM), tobacco abuse, and asthma is scheduled for bilateral hip replacement surgery. Preoperative laboratory results show a hematocrit (Hct) of 45%, blood urea nitrogen of 25 mg/dL, and creatinine of 1.0 mg/dL. Immediately following application of cement for the second hip, the patient became hypotension with sinus tachycardia. Arterial blood gas results reveal an Hct of 23% that responds toa crystalloid fluid bolus and blood transfusion (2 L crystalloids, 1 L albumin, and 2 U packed red blood cells). The possible cause(s) for the hypotension is/are
A. Hypovolemia and/or low Hct
B. Pulmonary embolism
C. Vasodilation caused by monomer of the bone cement
D. All of the above
D. Total hip arthroplasty surgery can be characterized by significant blood loss, especially in the situation of bilateral hip replacement. In acute bleeding, measuring an Hct may not accurately reflect the true value as equilibrium takes some time to show the true Hct. In addition, bone cement can cause vasodilation, which can further contribute to the low blood pressure. Cement placement has been associated with pulmonary embolism and pulmonary hypertension.
- A 68-year-old female (5’1” and 250 lb) with a medical history of chronic lower back pain and radiculopathy in the lumbar 4 to sacral 1 vertebral levels presents for anterior andposterior fusion. Her home medications include methadone 75 mg daily, oxycodone 10 mg every 3 hours as needed, a fentanyl patch (50 μg/h), and lisinopril 10 mg daily. The patient stated she has 7/10 pain daily. All of the following should be considered in the perioperative pain management regimen for this patient, except
A. Continue with daily methadone
B. Consider a perioperative ketamine infusion
C. Consider transversus abdominis plane (TAP) block for the anterior abdomen
D. Add ketorolac 30 mg every 6hours as needed for 14 days
D. Chronic pain is often a common occurrence in patients presented for spine/back surgeries. A multimodal therapeutic pain management strategy aimed at different pain cascade pathways is frequently utilized. It is a common practice to continue methadone if patients are already taking such medications and to consider starting methadone in patients with uncontrolled postoperative pain. Ketamine (GABA agonist) is effective in chronic pain patients. TAP blockade with local anesthetics can provide effective somatic pain relief of the anterior abdomen that will help in the treatment of incisional pain. Evidence supports the use of nonsteroidal anti-inflammatory drugs at low doses in spine surgeries, but higher concentrations have been associated with a rate of nonunion, so are therefore discouraged.
- You are administering anesthesia for a cervical spine procedure, and the surgeon has indicated that she plans to monitor somatosensory-evoked potentials (SSEPs) and motor-evoked potentials (MEPs). Your anesthetic plan includes avoidance of long-acting muscle relaxants in addition to avoiding the use of
A. 1 MAC or higher of sevoflurane as needed for maintenance anesthesia
B. Half MAC of nitrous oxide to supplement the inhalation agent
C. Continuous propofol infusion as anesthesia maintenance
D. Dexmedetomidine to smooth out the anesthetic delivery
A.
○ High concentrations of potent inhalational agents (such as desflurane and sevoflurane) may increase neuromonitoring latency and decrease amplitude of the SSEP and MEP.
○ Therefore, inhalation agents can be used for intraoperative maintenance anesthesia, but are used at less than one full MAC concentration.
○ Intravenous (IV) anesthetics are more commonly used for maintenance of anesthesia, as they are more compatible with SSEP and MEP neuromonitoring (some expected, but tolerable changes on either latency and/or amplitude).
○ These IV anesthetics include propofol,ketamine, etomidate, dexmedetomidine, benzodiazepines, and opioids independently and in various combinations.
○ Opioids have the least potential to interfere SSEP and MEP neuromonitoring.
All of the following can be used to assist in reducing the amount of perioperative surgical blood loss in an orthopedic procedures, except
A. Hemodilution
B. Controlled hypotension
C. Tranexamic acid
D. Aprotinin
- D.
○ Spine surgery can be associated with significant blood loss.
○ Surgical and anesthetic techniques that have been developed to control perioperative blood loss include hemodilution, autologous blood donation preoperatively, use of cell saver, and epinephrine at wound site.
○ Pharmacologically, antifibrinolyticssuch as tranexamic acid and ε-aminocaproic acid have been used with some efficacy.
• Tranexamic acid is a synthetic derivative of the amino acid lysine, and it is used to treat or prevent excessive blood loss during surgery and in various other medical conditions.
• Aprotinin has been associated with a 50% increase of cardiac side effects (myocardial infarction/congestive heart failure), increase (double) of the risk of stroke, and higher death rates (increased mortality).
All of the following statements when positioning patients for spinesurgery in the prone position are true, except
A. The neck should be in neutral position (without hyperextension or hyperflexion)
B. The eyes must be free of pressure and checked periodically
C. The abdomen must always be supported (never permitted to hang freely)
D. The arms are kept at less than 90 degrees of extension and flexion
- C. Prone positioning of patientsneeds to be carefully executed, especially during spine surgeries (prolonged procedures) and in patients who have other associated comorbidities such as rheumatoid arthritis and ankylosing spondylitis. The endotracheal tube needs to be properly secured, and eyes and nose should be padded and checked periodically to ensure that they are pressure-free. The neck and arms should be kept positioned in an anatomically neutral position. The abdomen needs to remain free to avoid increased venous pressure (assists in reducing increased venous bleeding) and to reduce the incidence of abdominal compartment syndrome that can develop during prolonged duration of surgical intervention and aggressive fluid administration.
