Benefits/Risks/Considerations for Regional Anesthesia (1,2,3)

  ii) Postoperative analgesia. Many patients will have significant pain after orthopedic surgeries and a plan for postoperative analgesia should be carefully considered.

(1) Peripheral nerve blockade with or without catheter

(2) Opioids for breakthrough pain

(3) NSAIDs and adjuvant analgesic medications

  iii) Optimize surgical exposure. Neuromuscular blockade or neuraxial anesthesia or peripheral nerve block is often required to facilitate optimal surgical exposure for orthopedic surgeries because they involve manipulation of the musculoskeletal system.

  iv) Prevent stretch/compression nerve injuries. Orthopedic surgeries can require the lateral, prone, or beach chair position; therefore, careful patient positioning is important to prevent injuries.

2) Local anesthetics in regional anesthesia

    a) Short- (chloroprocaine, lidocaine), intermediate- (mepivacaine), or long-acting (ropivacaine, bupivacaine) local anesthetics can be used for peripheral nerve blockade or neuraxial blockade depending on the duration of the procedure and the anticipated postoperative pain.

    b) Most peripheral nerve blocks are done with 20 to 40 mL of local anesthetic.

    c) The ideal spinal anesthetic for ambulatory surgery is controversial.

  i) Lidocaine has a 20% to 30% incidence of transient neurologic syndrome (TNS) especially when used for cases in the lithotomy position.

  ii) Mepivacaine has approximately a 6% TNS incidence (4).

  iii) Chloroprocaine has been used off-label for spinal anesthesia (5).

    d) Care should be taken for patients receiving a combination of anesthetic techniques in regard to local anesthetic toxicity (Table 135-1).

1) Upper extremity surgery— Shoulder, elbow, hand surgery (see Table 135-2)

Table 135-2
Regional Anesthetic Techniques for Upper Extremity Surgery

Duration of block performed with long-acting local anesthetic (bupivacaine or ropivacaine) is 12 to 20 hours; intermediate-acting agents (lidocaine or mepivacaine) will resolve after 4 to 6 hours.
Reproduced from Horlocker TT, Wedel DJ. Anesthesia for orthopaedic surgery. In: Barash PG, Cullen BF, Stoelting RK, et al., eds. Clinical Anesthesia. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009:1375–1392, with permission.

 

    a) Anesthetic considerations: Upper extremity surgery: peripheral nerve block with or without general anesthesia is often used.

  i) Surgery to the proximal arm may limit access to the airway. If the patient has received a regional anesthetic and airway obstruction is a concern, securing the airway with an LMA or an ETT at the beginning of the case may be prudent.

  ii) Placement of an IV line and NIBP on the nonoperative arm may interfere with infusions or fluid administration; therefore, consideration should be given to placement of a lower extremity IV.

  iii) For patients with comorbidities such as morbid obesity and significant coronary artery disease, invasive BP monitoring may be beneficial.

    b) Shoulder surgery

  i) Positioning—“Beach chair” or lateral position is often used. The patient’s neck should be maintained in a neutral position.

(1) Bezold-Jarish reflex—Profound hypotension and bradycardia can present in the beach chair position after interscalene block or with general anesthesia.

   (a) Pretreatment with β-adrenergic antagonists and vagolytics has been shown to prevent this reflex (6).

   (b) Treat with small doses of epinephrine (10 to 100 μg).

(2) Maintenance of cerebral perfusion pressure (CPP) in the beach chair position is critical. CPP is the net perfusion pressure causing blood to flow to the brain (CPP = MAP – ICP or CVP), whichever is greater). There have been case reports of cerebral ischemia in this position (7) as the brain is 20 to 30 cm higher than at the site of BP measurement; thus, the blood pressure is lower in the brain than in the arm. CPP can be maintained with fluids and vasopressors as needed.

    c) Hand and elbow surgery

  i) Positioning—Typically, the supine position is used. Occasionally, the patient may be lateral or prone.

  ii) See Table 135-2 for commonly placed peripheral nerve blocks.

  iii) Digital blocks—For distal extremity surgery, digital blocks that block the terminal branch of a nerve can be done by the surgeon or the anesthesiologist.

  iv) Bier block—This is an intravenous regional technique that provides complete anesthesia to an extremity distal to the tourniquet site. It is used in cases of <1.5 to 2 hours (8).

(1) An IV is inserted into the operative extremity. Another IV on the nonoperative side should also be placed for routine fluid and drug administration.

(2) A proximal and distal pneumatic tourniquet with alarms is placed on the operative extremity.

(3) The operative extremity is raised for at least 1 minute to allow for passive exsanguination.

(4) An Esmarch bandage is then wrapped from the distal part of the extremity until the tourniquet site to further exsanguinate the extremity.

(5) The proximal tourniquet is then inflated typically to 100 mm Hg greater than the systolic blood pressure.

(6) Once the tourniquet is adequately inflated, the Esmarch is released.

(7) Local anesthetic, typically lidocaine, is injected into the IV of the operative extremity.

(8) The local anesthetic will diffuse from the bloodstream to anesthetize the surrounding nerves.

(9) If the patient begins to complain of tourniquet pain, inflate the distal tourniquet and then deflate the proximal tourniquet.

(10) The tourniquets cannot be deflated until at least 30 minutes after injection of the local anesthetic for risk of local anesthetic toxicity.

(11) A 2-stage deflation of the cuff can be done by deflating for 10 seconds and then reinflating for 1 minute to slow the washout of the local anesthetic from the extremity.

4) Lower extremity surgery—hip, knee, ankle, and foot surgery (Table 135-3)

Table 135-3
Lumbosacral Techniques for Major Lower Extremity Surgery

PCA, patient-controlled analgesia; TKA, total knee arthroplasty; THA, total hip arthroplasty.
Duration of block performed with long-acting local anesthetic (bupivacaine or ropivacaine); intermediate-acting agents (lidocaine or mepivacaine) will resolve after 4 to 6 hours.
Outcomes most marked in patients who receive a continuous lumbar plexus catheter with infusion of 0.1% to 0.2% bupivacaine or ropivacaine at 6 to 12 mL/h for 48 to 72 h.
Reproduced from Horlocker TT. Anesthesia and pain management, Revision Hip and Knee Arthroplasty. Edited by Berry DJ, Trousdale RT, Dennis D, et al. 2008 Philadelphia, Lippincott Williams & Wilkins, with permission.

 

    a) Hip surgery

  i) Hip fracture

(1) Preoperative considerations

   (a) Consider the etiology of the fracture/fall and associated risks and comorbidities, for example, mechanical fall versus cardiac or neurologic cause that may require further workup (i.e., carotid duplex ultrasound, echocardiogram).

   (b) Delaying surgery for cardiac evaluation is an independent risk factor of postoperative complication, irrespective of the patient’s medical status (9).

   (c) Patients are often elderly.

     (i) They may have extensive comorbidities such as severe coronary artery disease, pulmonary disease, and renal disease.

     (ii) They can be hypovolemic from prolonged NPO status or diuretic use that may require aggressive fluid resuscitation and slow titration of anesthetics.

     (iii) Fluid administration should be done cautiously in patients with impaired left ventricular function.

(2) Intraoperative considerations/anesthetic techniques

   (a) Supine or lateral position.

   (b) Neuraxial anesthesia, lumbar plexus block, or general anesthesia.

     (i) Neuraxial anesthesia is typically preferred in patients with concomitant cardiopulmonary disease (see Table 135-1).

     (ii) General anesthesia is often preferable for patients unable to cooperate for neuraxial anesthesia and anticoagulated patients who require emergent surgery.

   (c) A preoperative femoral nerve or a fascia iliaca compartment block can be helpful in decreasing perioperative opioid requirements as well as for positioning for a neuraxial anesthetic (10,11).

   (d) Invasive blood pressure monitoring will depend on patient comorbidities such as extensive coronary artery disease or need for frequent blood sampling.

(3) Postoperative considerations

   (a) Patients are at high risk for thromboembolic complications

   (b) Patients often receive compression stocking and thromboprophylaxis medications (e.g., LMWH, Coumadin).

  ii) Total hip arthroplasty

(1) Intraoperative considerations

   (a) Commonly performed in the lateral position.

   (b) Anesthetic options include neuraxial or general anesthesia with/without a lumbar plexus block for postoperative analgesia.

   (c) Deliberate hypotension may be requested by the surgeon to decrease blood loss and improve surgical exposure.

     (i) Deliberate hypotension is a technique using neuraxial anesthesia, general anesthesia, or IV agents (antihypertensives such as labetalol, nicardipine, or IV sedatives like propofol) to intentionally decrease BP to a MAP of 50 to 65 mm Hg.

     (ii) The acceptable decrease in BP is controversial due to concerns of hypoperfusion and ischemia to vital organs. Benefits and risks must be weighed for each patient and patients with chronic hypertension may be at higher risk for ischemia (12,13).

    b) Knee surgery

  i) Total knee arthoplasty

(1) Intraoperative considerations

   (a) Supine position

   (b) Anesthetic options: Neuraxial anesthesia, femoral and sciatic nerve block, general anesthesia, or a combination of the above

(2) Postoperative analgesia

   (a) Epidural, spinal opioids, femoral block/catheter, sciatic block/catheter

  ii) Knee arthroscopy/ACL reconstruction

(1) Intraoperative considerations

   (a) Anesthetic options: Spinal, femoral and sciatic nerve block, general anesthesia, local and MAC

(2) Postoperative analgesia

   (a) Spinal opioids, femoral block/catheter, intra-articular opioids, local anesthetic infiltration

    c) Foot and ankle surgery (Table 135-4)

Table 135-4
Anesthetic Techniques for Common Foot and Ankle Operations

Femoral or saphenous block required if the incision extends to the medial aspect of the foot or ankle.
Reproduced from Horlocker TT, Wedel DJ. Anesthesia for orthopaedic surgery. In: Barash PG, Cullen BF, Stoelting RK, et al., eds. Clinical Anesthesia. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009:1375–1392, with permission.

 

  i) Intraoperative considerations

(1) Anesthetic options: Neuraxial anesthesia versus general anesthesia.

  ii) Postoperative analgesia

(1) Femoral with/without saphenous nerve block, popliteal nerve block, or ankle block.

5) Complications

    a) Fat embolus syndrome

  i) Definition: The triad of pulmonary distress, mental status changes, and petechial rash 24 to 48 hours after a pelvic or a long-bone fracture.

  ii) Signs and symptoms fall into major and minor criteria and are summarized in Table 135-5.

  iii) Treatment is supportive. Fluids and vasopressors should be used as needed to maintain hemodynamics.

    b) Bone cement implantation syndrome

  i) Definition: This syndrome is characterized by hypoxia, hypotension, and/or unexpected loss of consciousness occurring around the time of cementation, prosthesis insertion, reduction of the joint or, occasionally, during limb tourniquet deflation in a patient who has received cement.

  ii) Bone cement is used for arthroplasty (joint replacement surgery).

  iii) This can cause sudden hypotension, hypoxemia.

  iv) Treatment includes hydration, vasopressors, 100% FiO₂ (stop N₂O before methylmethacrylate is inserted) (14)

    c) Thromboembolic events—Orthopedic patients are at high risk of thromboembolic events such as deep vein thrombosis and pulmonary embolism.

  i) DVT prophylaxis should be initiated in every patient.

(1) Prophylaxis can range from encouraging ambulation, to compression stockings to pharmacological thromboprophylaxis.

  ii) The decision to perform neuraxial anesthesia in patients on anticoagulants should be based on the risks and benefits for each individual patient.

    d) Importantly, regional anesthesia techniques have been shown to decrease the risk of DVT and PE in patients who were not receiving pharmacologic prophylaxis (15).

    e) Tourniquets are often used in distal extremity surgery.

  i) A tourniquet is a pressure cuff that is inflated on the operative limb, proximal to the surgical site. Inflation of a tourniquet prevents blood flow to the limb and enables the surgeons to work in a bloodless field.

  ii) Prolonged tourniquet times typically are defined as >2 hours for the lower extremity and 90 minutes for the upper extremity and may result in permanent injury to muscles, vessels, and nerves.

  iii) Tourniquet pain is believed to involve type C pain fibers (16).

  iv) Tourniquet release leads to a transient metabolic acidosis often with an increase in ETCO₂, hypotension, and tachycardia.

  v) Tourniquet pain is best treated with release of the tourniquet. If it is not surgically possible to release the tourniquet, the anesthetic can be deepened.

    f) Peripheral nerve injury can occur due to a peripheral nerve block or the surgical procedure or be a complication from improper patient positioning.

    g) Comorbid conditions

  i) Patients with rheumatoid arthritis may have associated musculoskeletal, pulmonary, and cardiac complications in addition to cricoarytenoid arthritis and cervical spine instability requiring extra precautions.

6) Postoperative considerations

    a) Early mobilization is advantageous to improve rehabilitation.

    b) Lower extremity peripheral nerve blockade can allow patients to participate more fully in physical therapy.

    c) This benefit must be weighed against the possibility of fall risk in a patient with a dense block.

References

1. Wu CL, Fleisher LA. Outcomes research in regional anesthesia and analgesia. Anesth Analg 2000;91:1232–1242.

2. Hebl, JR. Ultrasound guided regional anesthesia and the prevention of neurologic injury: fact or fiction. Anesthesiology 2008;108:186–188.

3. Neal JM, Bernards CM, Hadzic A, et al. ASRA practice advisory on neurologic complications in regional anesthesia and pain medicine. Reg Anes Pain Med 2008;33:404–415.

4. YaDeau JT, Liguori GA, Zayas VM, et al. The incidence of transient neurologic symptoms after spinal anesthesia with mepivacaine. Anesth Analg 2005;101:661–665.

5. Yoos JR, Kopacz DJ. Spinal 2-chloroprocaine for surgery: an initial 10-month experience. Anesth Analg 2005;100:553–558.

6. Liguori GA, Kahn RL, Gordon J, et al. The use of metoprolol and glycopyrrolate to prevent hypotensive/bradycardic events during shoulder arthroscopy in the sitting position under interscalene block. Anesth Analg 1998;87:1320–1325.

7. Cullen DJ, Kirby RR. Beach chair position may decrease cerebral perfusion: catastrophic outcomes have occurred. APSF Newsletter 2007;22(2):25–27.

8. Van Zundert A, Hemstadter A, Goerig M, et al. Centennial of intravenous regional anesthesia. Bier’s Block (1908–2008). Reg Anesth Pain Med 2008;33:483–489.

9. Cluett J, Caplan J, Yu W. Preoperative cardiac evaluation of patients with acute hip fracture. Am J Orthop 2008;37(1):32–36.

10. Pedersen SJ, Borgbjerg FM, Schousboe B, et al. A comprehensive hip fracture program reduces complication rates and mortality. J Am Geriatr Soc 2008;56:1831–1838.

11. Parker MJ, Griffiths R, Appadu B. Nerve blocks for hip fractures (review). Cochrane Datab Syst Rev 2002;1.

12. Sharrock NE, Bading B, Mineo R, et al. Deliberate hypotensive epidural anesthesia for patients with normal and low cardiac output. Anesth Analg 1994;79:899–904.

13. Williams-Russo P, Sharrock NE, Mattis S, et al. Randomized trial of hypotensive epidural anesthesia in older adults. Anesth 1999;91:926–935.

14. Donaldson AJ, Thomson HE, Harper NJ, et al. Bone cement implantation syndrome. Br J Anaesth 2009;102(1):12–22.

15. Modig J, Borg T, Karlstrom G, et al. Thromboembolism after total hip replacement. Anesth Analg 1983;62:174–180.

16. Concepcion, MA, Lambert DH, Welch KH, et al. Tourniquet pain during spinal anesthesia. Anesth Analg 1988;67:828–832.

17. Horlocker TT, Wedel DJ. Anesthesia for orthopaedic surgery. In: Barash PG, Cullen BF, Stoelting RK, et al., eds. Clinical Anesthesia. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009:1375–1392.

Suggested Readings

18. Horlocker TT, Wedel DJ. Anesthesia for orthopaedic surgery. In: Barash PG, Cullen BF, Stoelting RK, et al., eds. Clinical Anesthesia. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009:1375–1392.

19. Neal JM, Gerancher JC, Hebl JR, et al. Upper extremity regional anesthesia: essentials of our current understanding. Reg Anes Pain Med 2008;34(2):134–170.

20. Enneking KF, Chan V, Greger J, et al. Lower extremity peripheral nerve blockade: essentials of our current understanding. Reg Anes Pain Med 2005;30(1):4–35.

Anesthesia for Eye Surgery

Brian M. Davidson, MD

1) Ocular physiology

    a) IOP is the pressure within the rigid globe of the eye.

    b) Increases in IOP

  i) Increased IOP may result in extrusion of vitreous humor in the situations such as an open globe during a surgical procedure or trauma.

  ii) Increased IOP may result from increases in arterial BP, central or local venous pressure, and local external pressure increases on the eye (1).

    c) Anesthesia events/procedures that may increase IOP

  i) Direct laryngoscopy and intubation

  ii) High ventilation pressures—both endotracheal and mask

  iii) Trendelenburg position

2) Anesthetics and IOP

    a) Most anesthetic agents (volatiles, opiates, induction agents, benzodiazepines) reduce IOP.

  i) Mechanism

(1) A combination of decreases in systemic vascular pressures, muscle relaxation (extraocular), and pupillary constriction (↑ aqueous outflow).

    b) Ketamine

  i) May increase IOP due to its sympathomimetic effects and tendency to raise BP

  ii) Lacks muscle relaxation properties

    c) Succinylcholine

  i) May increase IOP via depolarization of extraocular muscles

  ii) The effect may last up to 10 minutes

  iii) Relatively contraindicated for induction in open globe trauma or in patients with known increases in IOP.

  iv) Anesthesia providers must use clinical judgment when weighing the risk of increased IOP versus the risk of aspiration and hypoxia in patients requiring rapid sequence induction (RSI) or with known or potential difficult airways (2).

    d) Nondepolarizing muscle relaxants do not increase IOP

1) Anticholinergic medications

    a) Topical anticholinergics cause pupil dilation (mydriasis) and may precipitate closed-angle glaucoma.

    b) Systemic atropine and glycopyrolate are not associated with ↑IOP (1).

4) Oculocardiac reflex

    a) Results from traction on the eye or extraocular muscles.

    b) Signs and symptoms

  i) Bradycardia, junctional rhythm, ventricular ectopy, or asystole

  ii) Awake patients may experience nausea or somnolence.

    c) OCR involves the ophthalmic trigeminal (V¹) afferent and vagal (X) efferent pathway (1).

    d) More common in pediatric patients undergoing strabismus surgery.

    e) Prevention and treatment (Table 136-1)

  i) Administer anticholinergic drugs such as atropine (10 μg/kg) or glycopyrolate (4 μg/kg).

(1) Use with caution in patients with coronary artery disease.

(2) Care should also be taken when using atropine in elderly patients due to CNS effects.

(3) The rapid onset of atropine may make it the medication of choice in dire clinical situations (1).

5) Systemic effects of ophthalmic medications

    a) Topical medications

  i) Used frequently and absorbed into the body through blood vessels in the eye.

  ii) Rate of absorption is slower than IV but faster than subcutaneous route of administration.

(1) Echothiophate: Irreversible cholinesterase inhibitor for treatment of glaucoma.

   (a) Side effects may include blurred vision, headache, eye erythema, and local or systemic allergic reaction.

(2) Epinephrine: Topical drops used to reduce bleeding in topical ophthalmic procedures

   (a) May cause tachycardia, hypertension, and dysrhythmias in patients with and without a previous cardiac history.

(3) Timolol: β-Adrenergic antagonist used to lower IOP by reducing aqueous humor production

   (a) Rare reports of hypotension, bradycardia, and bronchospasm

6) Intraocular gas expansion

    a) Gas bubble may be placed by ophthalmologist into posterior chamber to aid repair of a detached retina.

     (i) Avoid nitrous oxide for the entire case or within 10 minutes of any gas bubble insertion.

    b) Sulfur hexafluoride (SF6) may be used for the bubble owing to its lower solubility and prolonged therapeutic effect (1).

     (i) SF6 bubble will increase in size naturally and stay in place up to 10 days.

7) Anesthesia for eye surgery. General, regional, and topical anesthesia approaches are available for ophthalmic surgery patients.

    a) Preoperative considerations

  i) Patient undergoing many eye procedures may be older and have significant systemic medical conditions.

  ii) The ophthalmic surgery patient is more likely to have cardiac, respiratory, endocrine, and orthopedic pathology.

  iii) Appropriate preoperative testing and evaluation should occur in these patients even though the inherent risk of most ophthalmic procedures is low.

  iv) The patients’ ability to cooperate and remain still in the supine position must be confirmed before sedation is considered for the anesthetic plan.

    b) Intraoperative considerations

  i) Airway access may be limited as the patient’s head is usually 90 to 180 degrees from the anesthesiologist

  ii) Standard ASA monitoring requirements apply. Consider special monitors based on the patient’s medical history and condition.

  iii) General anesthesia

(1) Indicated for more invasive procedures and uncooperative patients

(2) Choice of induction technique is based on patient’s general medical condition.

   (a) Trauma patients may require RSI without the use of succinylcholine (2).

   (b) Succinylcholine avoidance with open globe injuries has been suggested as it may increase IOP and result in extravasation of ocular contents. Although clinical evidence supporting such avoidance is very limited, succinylcholine has been used successfully in open globe injuries in patients requiring RSI (2).

   (c) Hypoxia and hypercarbia also greatly increase IOP, making a failed airway an equally problematic situation.

(3) Patients with traumatic rupture (an open globe) require special care

   (a) IOP must be controlled during induction and maintenance of anesthesia in order to prevent extrusion of vitreous.

   (b) Deep anesthesia should be maintained to prevent increases in IOP.

   (c) Paralysis to prevent movement should be strongly considered.

   (d) Hemodynamic control is essential

   (e) Smooth extubation plan is necessary to avoid valsalva from coughing.

     (i) Consider extubating the patient under deep anesthesia (contraindicated with difficult airway or full stomach).

     (ii) Lidocaine 1.5 mg/kg 2 minutes prior to extubation may reduce laryngeal responsiveness and facilitate extubation.

     (iii) Remifentanil (0.025 to 0.1 μg/kg/min) infusion may also be used to provide a smooth emergence with reduced coughing.

  iv) Regional and topical anesthesia (see below for techniques)

(1) Most common technique for nontraumatic eye surgeries

(2) Sedation must be kept to a minimum for ophthalmic surgery because patient cooperation and stillness are necessary for most of the intraoperative period (1).

   (a) Short periods of heavier sedation are appropriate for placement of regional blocks (3).

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