What the Anesthesiologist Should Know before the Operative Procedure?
Femoral shaft fractures are usually associated with trauma, ranging from gunshot wounds to severe motor vehicle accidents with multiple associated injuries to “trips and falls” in osteoporotic elderly patients. While early external stabilization (bedside traction pin) is frequently performed, urgent repair is the general approach. “Pathological” fracture at the site of a cancer metastasis is another etiology, but is less common.
The two major associated issues are (1) the presence of other organ system injuries in the case of trauma, often in otherwise healthy young individuals, or (2) the existence of associated comorbidities in the elderly victim of a fall. Up to 6% of femoral shaft fractures are associated with an ipsilateral femoral head fracture and bilateral femoral fractures portend a greater risk for pulmonary complications and mortality. Surrounding vascular or muscle injuries should be investigated early and treated as ischemia and resulting rhabodmyolysis, respectively, can increase morbidity in these patients.
Two injury-specific issues for the anesthesiologist are associated blood loss (as much as a liter of lost blood can be sequestered in the thigh) and the potential for fat embolism, either associated with the injury or the repair (more likely with the femoral shaft reaming associated with the use of intramedullary rods). The two surgical approaches are either fixation with plates and screws along the femoral shaft or intramedullary rods. The latter is the more common technique and is usually performed from the proximal end (anterograde) unless there are bilateral injuries, tibial fractures, obesity, pregnancy (less X-ray exposure with the retrograde technique), or other issues that make positioning more difficult.
1. What is the urgency of the surgery?
What is the risk of delay in order to obtain additional preoperative information?
As with fractures of the hip, early repair is desirable to provide pain control, promote mobilization, reduce infection risk in open fractures and possibly reduce ongoing occult blood loss and deep vein thrombosis formation. Furthermore, fixation and/or repair has the benefit of reducing secondary pulmonary injury due to fat emboli and pulmonary capillary permeability. Occasionally, this procedure will be performed for a nonunion or malunion of a previous fracture and can be managed in a more elective fashion.
Emergent: If the fracture is associated with significant blood loss, neurovascular compromise or compartment syndrome, reduction of the fracture may be emergent and will be considered a component of damage-control trauma orthopedic care. External traction can provide sufficient stabilization to allow blood replacement and assessment of other injuries which would then allow definitive fixation to be performed in a non-emergent manner. If other major organ (thoracic, abdominal, pelvic or intracranial) injuries are discovered, surgical treatment of these injuries will take priority.
Urgent: Most acute fractures fall in the urgent category with all open fractures preferably addressed within 24 hours of the injury and closed fractures within at least 48 hours of the fracture. Appropriate fluid or blood replacement and stabilization should be optimized. In the polytrauma patient, stabilization can be critical to reduce morbidity and must be accomplished when feasibly possible. If the patient is too morbid due to other illness or injuries (cardiac, pulmonary, neurologic), external fixation should be considered either bedside or in the operating room while minimizing impairment to other organ systems. For example, in a patient with increased intracranial pressure (ICP) and no thoracolumbar spine injuries, positioning the patient’s head up in 45 degrees should be maintained while an external fixator is placed quickly on the femur.
Elective: Scheduled procedures are reserved for revisions of previous reductions or “prophylactic” stabilization of a metastatic lesion in the femur after an appropriate cancer workup.
2. Preoperative evaluation
The major consideration in the patient with a femur fracture is the existence of other injuries. If the etiology is trauma, acute hemorrhage in the chest, abdomen, pelvis or head must be excluded. Furthermore, pulmonary injury or increased ICP from associated head injuries may preclude definitive internal fixation until those conditions are optimized. In the elderly patient who has suffered a fall, thorough neurologic evaluation needs to be performed to ensure that a cerebral vascular accident or cardiac etiology do not feed further diagnostics and treatment. Appropriate risk stratification and clearance should be performed by the trauma, critical care, and neurology/neurosurgical teams when indicated. In the absence of other injuries, nerve and vascular injuries to the involved leg must be assessed, and may necessitate early intervention. Finally, preoperative replacement of blood loss from the femur fracture itself is indicated if there is hemodynamic instability and other sources of bleeding have been ruled out.
Medically unstable conditions warranting further evaluation include hemodynamic instability, which mandates assessment for other occult sites of bleeding (and replacement of blood volume with appropriate fluids or blood itself), cardiopulmonary insufficiency due to acute disease or injury and severe head trauma with critical intracranial hypertension. When feasible, external fixation or even bedside traction should be pursued at the minimum.
Neurologic symptoms should be thoroughly evaluated to establish a baseline. If vascular lesions are present which would indicate anticoagulation therapy, coordination with a neurologist is needed to evaluate the risk-benefit aspects of delaying anticoagulation until after surgical repair. As mentioned, concomitant brain injury with increased ICP also warrants appropriate management in concert with the trauma, critical care or neurosurgical providers.
Delaying surgery may be indicated if hemodynamic instability is present or there is unmanageable intracranial hypertension. Deep anesthesia and laying flat trials might be conducted in the intensive care unit to determine how the patient might react to an operative fixation or stabilization in the supine position.
3. What are the implications of co-existing disease on perioperative care?
b. Cardiovascular system
Acute/unstable conditions: Decreased intravascular volume due to blood loss and trauma represent the majority of co-existing conditions that require preoperative optimization. Replacement can generally be based on routine vital signs, but in the presence of concurrent cardiac dysfunction, invasive monitoring or transthoracic echocardiographic assessment may be indicated.
Myocardial contusion, tamponade, and in rare cases myocardial ischemia or infarct are possibilities with trauma and need to be evaluated and addressed prior to definitive fixation of the femur.
Baseline coronary artery disease or cardiac dysfunction – Goals of management: The usual American Heart Association/ American College of Cardiology (AHA/ACC) screening evaluation should be performed, but the urgency of the surgery often dictates proceeding to the operating room before performing further diagnostic or interventional approaches. Beta blockade should be maintained only if the patient is hemodynamically stable and no occult bleeding is detected.
Pulmonary contusion is the most likely associated injury when multiple trauma is involved. This should be managed with appropriate therapy, which could include interventions ranging from supplemental oxygen to intubation and positive-pressure ventilation.
Clinically significant pulmonary embolization from fat may occur with the fracture or during intraoperative fixation, as often as 10 – 15 % of the time. Oxygenation should be monitored closely and serial arterial blood gasses may be warranted to determine the extent of pulmonary compromise. One must be very vigilant during a planned fixation of bilateral femoral fractures as the risk of respiratory failure can increase dramatically. Reviewing the pH, pO2, lactate, base deficit, and oxygen requirements after the first repair is strongly encouraged before allowing the surgeons to definitively fix the contralateral fracture.
COPD: If pre-existing disease is present, therapy should be continued. Insertion of an arterial catheter may be indicated to allow closer monitoring, particularly since the risk of fat embolization would represent a greater challenge to patients who are already compromised.
OSA: Patients with sleep apnea should have the severity of the disease assessed, and appropriate strategies in place to reduce the potential for postoperative exacerbation of their disease by opioid-induced respiratory depression. The use of CPAP therapy in the perioperative period is encouraged.
Reactive airway disease (Asthma): Maintenance of regular therapy should be continued, and careful attention to new onset wheezing should be evaluated and treated with consideration for fat embolization as an etiology.
Acute renal insufficiency may be common in the trauma patient due to a multitude of factors. Severe hypotension in the bleeding patient, intravenous contrast for CT scans, and muscle injury causing rhabodmyolysis might all contribute to acute renal compromise. Urine output should be monitored to ensure adequate volume replacement and renal function and serial chemistry panels might be prudent to prevent hyperkalemic complications in more significant injuries.
Acute issues: As mentioned above, careful assessment for stroke symptoms are indicated in the elderly patient suffering a fall and concomitant head injuries need to be evaluated for intracranial hypertension.
Neurologic assessment of the involved leg is also necessary to detect nerve injury to the femoral, obturator or sciatic nerve. Presence of nerve deficits should be documented thoroughly, and may be an indication for early intervention. Presence of a deficit may mitigate against a long-acting regional block technique if close postoperative assessment is indicated.
Trauma victims should also be assessed for drug intoxication and chronic use of narcotic and illicit drugs as that may affect their neurologic assessment and/or anesthetic management.
Chronic disease: Pre-existing neurologic conditions must be taken into account and followed post-operatively to ensure the patient returns to their baseline.
Diabetic patients can experience more pronounced hyperglycemia post-trauma. Blood sugar levels should be monitored and treated appropriately. Other stable endocrine diseases should be treated and managed in the standard fashion in the perioperative period.
g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan:
The potential for significant coagulopathy exists in the multi-trauma patient for a variety of factors (acute coagulopathy of trauma, dilutional coagulopathy, etc.). Monitoring of coagulation factors, especially INR, PTT, and platelet count, may be indicated. Many trauma centers are adding viscoelastic monitoring in the form of thromboelastography to better assess and monitor platelet function, clot strength and fibrinolysis. Proper protocols or discussions with the trauma and orthopedic services should help guide peri-operative optimization.
Cancer patients undergoing a “prophylactic” repair may have been subjected to chemotherapy agents that might affect anesthetic choices. Careful review of previous medications is appropriate in these circumstances.
4. What are the patient’s medications and how should they be managed in the perioperative period?
h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
Frequently, discontinuation of anticoagulants and platelet function inhibitors is recommended prior to elective orthopedic surgery, but this is often not possible with urgent surgery. Chronic aspirin, herbal medication, or NSAID usage may be associated with an increase in blood loss, but generally the urgency of surgery requires proceeding without delay. The same consideration is true for platelet inhibitors such as clopidogrel (Plavix) and newer members of this drug family. These drugs are challenging because of their greater potency, the lack of an accurate monitoring mechanism, and paucity of reversal agents. Fortunately, patients on warfarin can have their anticoagulation status reversed with the use of vitamin K (if time allows) or infusion of fresh frozen plasma.
i. What should be recommended with regard to continuation of medications taken chronically?
Cardiac: Antianginal medications should be continued, with the caveat that beta blockers may have to be held temporarily in the presence of hypotension. The same is true for antihypertensive medications, although they should be re-started as soon as blood loss is controlled and hemodynamic stability is achieved.
Pulmonary: Bronchodilators should be continued.
Renal: Diuretics, like beta blockers, should be held in the presence of hypovolemic hypotension.
Neurologic: Anti-seizure medication should be continued. A special issue beyond the scope of this short chapter is the issue of chronic opioid use. If that situation exists, the patient’s normal daily opioid requirement needs to be administered on a regular basis and additional medication made available for the additional pain associated with the surgery.
Antiplatelet: See above.
Psychiatric: The anesthesiologist needs to be aware of any potential interactions with chronic antipsychotic medications and these medications need to be resumed in the postoperative period.
j. How to modify care for patients with known allergies:
Avoid medications to which the patient is allergic.
k. Latex allergy:
If the patient has a sensitivity or an allergy to latex, prepare the operating room with latex-free products and avoid use of any latex-containing equipment. The risk of oversight in the emergent surgery scenario warrants double-checking the equipment for latex content.
l. Does the patient have any antibiotic allergies:
Standard antibiotic prophylaxis for this surgery is 1-2 g cephazolin intravenously within 60 minutes of the skin incision. If there is an open wound, antibiotics may have been started earlier. In the event of penicillin allergy, 1 g vancomycin or 900 mg clindamycin are effective alternatives, with vancomycin preferable if there is a possibility of MRSA colonization.
m. Does the patient have a history of allergy to anesthesia?
Malignant hyperthermia (MH)
Patients with femur fractures do not present a greater risk of malignant hyperthermia although a traumatic etiology which may include substantial muscle injury can at times present similar MH symptomology and complications in the peri-operative period. Astute clinical evaluation is required in those cases.
If the patient has a history of documented MH: Avoid all trigger agents such as succinylcholine and inhalational agents:
Proposed general anesthetic plan: intravenous techniques with nondepolarizing muscle relaxants, propofol, and opioids are acceptable. Regional anesthesia is a highly desirable alternative in this situation.
Ensure an MH cart and a copy of the MHAUS (Malignant Hyperthermia Association of the United States) protocol are available.
Family history or risk factors for MH: if there is a history strongly suggestive of MH, regional anesthesia or general anesthesia using nontriggering agents is preferable.
Local anesthetics/muscle relaxants:
Allergy to these medications are rare. However, if present, offending drugs should be avoided.
5. What laboratory tests should be obtained and has everything been reviewed?
Hemoglobin levels should be assessed preoperatively and at times might need to be corrected before surgery. Blood loss with the procedure is frequently 750-100 mL and may require further monitoring and blood replacement intraoperatively.
Electrolytes are usually stable unless significant muscle injury is present or massive transfusion is administered. Serial evaluations of potassium, BUN, Cr, glucose, HCO3, ionized calcium and lactates are encouraged in the severely injured patient to assess resuscitative efforts and portend complications from electrolytes disturbances.
Coagulation panel: Similar to electrolytes, coagulation factors and platelet function might be altered in the critically injured patient or one who has received a massive transfusion. Periodic coagulation studies and viscoelastic monitoring might offer transfusion guidance in these patients.
Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
Both regional and general anesthesia are acceptable techniques. However, most commonly these patients are managed with general anesthesia intraoperatively and a regional anesthetic technique for postoperative analgesia. In the presence of major blood loss and hemodynamic instability, or coagulopathy due to blood loss or anticoagulant therapy, neuraxial blocks may represent a greater risk of hypotension or neuraxial hematoma. General anesthesia with potent inhalation anesthetics may likewise be associated with hypotension in these situations, and care is advised.
Utilizing peripheral nerve blocks alone (with minimal sedation) will often require a posterior lumbar plexus block and a transgluteal (or more proximal) sciatic block to anesthetize all the nerves of the lower extremity. This can be quite challenging in the injured patient as positioning changes can cause significant pain and these blocks are considered more advanced techniques requiring providers to have particular experience with advanced regional anesthesia procedures. Finally, not all fractures are created equal and occasionally the surgical technique might outlast the single shot nerve block techniques.
As mentioned, a combination of general anesthesia and a regional block is often the anesthetic of choice. While a femoral block will not provide complete analgesia, it provides significant pain reduction in these fractures and after repairs as the femoral nerve is the most significant nerve contributing to the sensory supply of the femoral shaft. Femoral nerve blocks can be performed as single shot blocks with a long-acting drug such as bupivacaine or ropivacaine or can provide continuous analgesia via a continuous perineural catheter. These blocks can be performed in the emergency department after thorough initial neurologic assessment, and may allow greater patient comfort during subsequent evaluation as well as prevent the side effects associated with opioids (nausea, respiratory and mental status depression, hypotension). Those unexperienced with femoral nerve blocks can utilize the “fascia iliaca” technique to provide an infiltration of local anesthetic into the subfascial plane without much patient movement or cooperation.
a. Regional anesthesia
Benefits: Subarachnoid or epidural anesthesia provide dense anesthesia for these procedures with profound motor blockade that facilitates surgical manipulation. These techniques can also avoid airway manipulation, and, in the elderly patient, can allow for avoidance of prolonged sedation and reduce postoperative confusion. The use of a combined spinal-epidural technique can provide rapid onset of dense anesthesia for the procedure and indefinite prolongation of anesthesia if the operation outlasts the duration of the initial spinal anesthetic. Epidural infusions can also provide prolonged postoperative analgesia, if there are no contraindications due to coagulation status or anticoagulation therapy.
Drawbacks: A lower extremity sympathectomy associated with neuraxial techniques can aggravate hypotension in the presence of uncorrected blood loss. Appropriate volume resuscitation and local anesthetic titration via an epidural catheter is advised.
Issues: Volume status, anticoagulation status
Peripheral nerve block
An obturator and proximal sciatic block (in addition to the femoral) will be needed to provide full anesthesia for the upper leg and may not be adequate to block proximal tourniquet discomfort if one is used for a distal operation.
Benefits: The multiple blocks can provide good anesthesia for the procedure but are not as dense a motor blockade of the muscles to the leg. Peripheral blocks are not associated with the risk of hypotension induced with neuraxial anesthesia.
Drawbacks: Performance of the multiple blocks may be more uncomfortable for the patient with an acute fracture and one must take into account possible toxicity if large volumes of local anesthetics are required for multiple regional anesthetics.
Issues: Residual block may make assessment of a peripheral nerve injury more difficult. Compartment syndrome is generally not a problem with this procedure unless the injury was due to a high velocity force (such as a blast injury or short range gun shot wound). Consultation with the orthopedic is recommended prior to implementing regional anesthesia techniques.
b. General Anesthesia
Benefits: General anesthesia can provide better adjustment of the duration of anesthesia than a spinal block, and can be tailored to reduce the hemodynamic changes that might be precipitated by hypovolemia. It can also provide control of ventilation in the event of pulmonary contusion or secondary pulmonary injury.
Drawbacks: Postoperative analgesia will require opioid administration, which comes with a host of side effects, or a regional anesthetic to make patients comfortable.
Other issues: Muscle relaxation may be requested to facilitate reduction.
Airway concerns are not different from the ordinary ones encountered in other procedures. If the procedure (such as intramedullary rodding) is done in the lateral position, careful securing of the airway device is important.
c. Monitored Anesthesia Care
Not appropriate for this procedure
6. What is the author’s preferred method of anesthesia technique and why?
In our institution, femoral nerve blocks are performed frequently in conjuction with mild sedation for the initial traction pinning and reduction in the trauma bays. Intraoperatively, patients are managed with a general anesthetic with a single shot or continuous femoral nerve block performed either shortly before induction or soon after surgical completion depending on operating room flow and personnel availability. The block provides excellent muscle relaxation, avoidance of postoperative confusion, and an opportunity for continuous postoperative analgesia. Other centers might prefer a combined spinal-epidural technique which can provide an excellent rapid-onset of dense block with an option for continuous postoperative analgesia (if anticoagulation is managed appropriately), however, in our experience, this approach might unmask occult blood loss and subclinical hypovolemia in the acute trauma patient and lead to difficult to treat hypotension.
What prophylactic antibiotics should be administered?
As mentioned, cefazolin 1-2 g IV is the standard. Clindamycin or vancomycin (in MRSA colonized patients) are reasonable alternatives.
What do I need to know about the surgical technique to optimize my anesthetic care?
Positioning varies dependent on the surgical approach and surgeon preference. At times, it is performed supine on a fracture table, or supine or lateral on a radiolucent table. Blood loss can be from 150-1000 mL, depending on the extent of the injury and if intrafemoral reaming is performed, and should be anticipated and corrected as necessary. Large bore intravenous access is indicated and at times an arterial line and/or central line might be more appropriate in the multi-trauma patient or elderly patient with multiple co-morbidities.
What can I do intraoperatively to assist the surgeon and optimize patient care?
Cell salvage units may be useful, though not if extensive reaming will introduce fat and bone debris into the collection. Muscle relaxation either from a neuraxial block or with nondepolarizing drugs will assist the surgeon with the reduction and fixation. Provision of adequate analgesia, either with a continuous nerve block or systemic opioids, should be planned in advance and instituted intraoperatively to avoid emergence discomfort. If preoperative nerve damage is present, anesthetic technique and analgesia should be adjusted to allow appropriate monitoring in cooperation with the surgical team.
What are the most common intraoperative complications and how can they be avoided/treated?
The most common intraoperative challenge is ongoing blood loss which should be replaced concurrently with crystalloid or blood products when necessary. Urine output should be monitored closely to ensure volume replacement and intact renal function. Pulmonary embolism from fat is a risk as is pulmonary deterioration in pre-existing lung disease or injury. Judicious management of volume status and careful and serial attention to oxygen saturation and laboratory values (pH, pO2, lactate, potassium, ionized calcium, creatinine, haemoglobin) should help avoid worsening lung failure, under-resuscitation and occult hypoperfusion syndrome. If the patient’s condition worsens, consideration of a curtailed surgical technique (potentially just an external fixator) should be discussed with the surgical team.
Cardiac: As mentioned, hypotension and hemodilution (from crystalloid resuscitation) are the greatest risks. If severe, myocardial oxygen supply may be compromised and ischemia is a possibility.
Pulmonary: As mentioned, fat embolization or worsening lung injury may produce hypoxemia and worsening pulmonary mechanics. More advanced ventilation strategies and postoperative mechanical ventilation may need to be implemented.
If the patient is intubated, are there any special criteria for extubation? See above.
Neurologic: Nerve damage to the terminal nerves of the leg is possible, especially in the setting of trauma. In rare cases of high velocity injuries, compartment syndrome of the thigh might also present with secondary nerve impairment.
c. Postoperative management
What analgesic modalities can I implement?
Systemic opioids remains the mainstay of analgesia, however, use of a multimodal approach with acetaminophen, anti-inflammatory agents, gabapentinoids, and other adjuncts will help reduce side effects from any one particular agent. Epidural analgesia is possible, but the lumbar level of block may produce motor weakness that interferes with ambulation and rehabilitation. It may be preferable in the elderly to avoid systemic medication if mental confusion is present. Femoral nerve blockade is very helpful, but will not necessarily provide complete analgesia.
What level bed acuity is appropriate?
Patients can generally be cared for on a standard orthopedic ward unless there was significant blood loss and fluid changes or worsening lung function as a result of the fixation. Of course, in the multi-trauma patient requiring intensive care for other reasons, upgrading postoperative care is mandated.
What are common postoperative complications, and ways to prevent and treat them?
Delirium in the elderly is a possibility especially when general anesthesia is used and reduced levels of systemic medications are helpful. In young patients, residual hypovolemia may cause persistent hemodynamic instability and pain remains the most common complaint. Multi-modal analgesic strategies is strongly advised.
What’s the Evidence?
Jaffe, RA, Schmiesing, CA. “Anesthesiologists’ manual of surgical procedures”. 2014.
Scannell, BP, Waldrop, NE, Sasser, HC, Sing, RF, Bosse, MJ. “Skeletal traction versus external fixation in the initial temporization of femoral shaft fractures in severely injured patients”. J Trauma. vol. 68. 2010 Mar. pp. 633-40.
FEMORAL NERVE BLOCKS
Mutty, CE, Jensen, EJ, Manka, MA, Andres, MJ, Bone, LB. “Femoral nerve block for diaphyseal and distal femoral fractures in the emergency department”. J Bone Joint Surg. vol. 89. 2007. pp. 2599-603.
Wathen, JE, Gao, D, Merritt, G, Georgopoulos, G, Battan, FK. “A randomized controlled trial comparing a fascia iliaca compartment nerve block to a traditional systemic analgesic for femur fractures in a pediatric emergency department”. Ann Emerg Med.. vol. 50. 2007. pp. 162-71.
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- What the Anesthesiologist Should Know before the Operative Procedure?
- 1. What is the urgency of the surgery?
- What is the risk of delay in order to obtain additional preoperative information?
- 2. Preoperative evaluation
- 3. What are the implications of co-existing disease on perioperative care?
- b. Cardiovascular system
- c. Pulmonary
- d. Renal-GI:
- e. Neurologic:
- f. Endocrine:
- g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan:
- 4. What are the patient’s medications and how should they be managed in the perioperative period?
- h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
- i. What should be recommended with regard to continuation of medications taken chronically?
- j. How to modify care for patients with known allergies:
- k. Latex allergy:
- l. Does the patient have any antibiotic allergies:
- m. Does the patient have a history of allergy to anesthesia?
- 5. What laboratory tests should be obtained and has everything been reviewed?
- Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
- a. Regional anesthesia
- b. General Anesthesia
- c. Monitored Anesthesia Care
- 6. What is the author’s preferred method of anesthesia technique and why?
- What prophylactic antibiotics should be administered?
- What do I need to know about the surgical technique to optimize my anesthetic care?
- What can I do intraoperatively to assist the surgeon and optimize patient care?
- What are the most common intraoperative complications and how can they be avoided/treated?
- c. Postoperative management