Questions

Question 1

Is RA just a disease of the joint and adjacent connective tissue?

Answer 1

RA is a chronic inflammatory disease, which initially destroys joints and adjacent connective tissue and then progresses to a systemic disease affecting major organ systems.

Question 2

What are some of the clinical manifestations of RA

Answer 2

Systemic manifestations of RA are widespread. They may include pulmonary involvement with interstitial fibrosis and cysts with honeycombing, gastritis and ulcers from aspirin and other analgesics, neuropathy, nephropathy, muscle wasting, vasculitis, and anemia. Ultimately the anatomy of the airway is damaged and altered in patients with rheumatoid arthritis

Question 3

What are some airway abnormalities that can occur in patients with RA

Answer 3

Some airway abnormalities that can occur in patients with rheumatoid arthritis include decreased mouth opening, a hypoplastic mandible, cricoarytenoid arthritis, and cervical spine abnormalities. (

Question 4

Why might the airway opening be decreased in patients with RA

Answer 4

Normal mouth opening may be decreased in patients with rheumatoid arthritis as a result of temporomandibular arthritis. (

Question 5

What occurs to the developing mandible in patients with juvenile RA

Answer 5

Thepatient with juvenile rheumatoid arthritis often has a hypoplastic mandible as a result of early fusion. This results in the noticeable overbite in some patients with RA. (

Question 6

What are some of the clinical manifestations of cricoaryteniids arthritis

Answer 6

As with other joints, the cricoarytenoid joint may be affected by rheumatoid arthritis. Cricoarytenoid arthritis may result in shortness of breath and snoring. RA patients have been misdiagnosed as having sleep apnea when in fact they have cricoarytenoid arthritis. Patients with cricoarytenoid arthritis may present with stridor on inspiration. This may present in the postanesthesia care unit (PACU) while the patient is recovering from anesthesia. Acute subluxation of the cricoarytenoid joint, as a result of tracheal intubation, can cause stridor as well, and it is not responsive to racemic epinephrine.

Question 7

Can neck movement in patients with RA

Answer 7

Yes, movement of the neck in patients with RA can result in cervical spine injury. The patient must be carefully evaluated for both the complexity and the risk of endotracheal intubation because of difficulty in visualizing the airway as a result of the anatomic changes that occur. Normal endotracheal intubation maneuvers with neck movement may result in an increased risk of cervical spine injury due to destruction of the bones and ligaments of the cervical spine. These can place the cervical spinal cord at risk. Many cervical spine abnormalities may occur in patients with RA

Question 8

Can neck movement in patients withRA resultin cervical spine injury? What is the clinical implication of this?

Answer 8

Three abnormal movements of the cervical spine that may be manifest in patients with rheumatoid arthritis include atlantoaxial subluxation, subaxial subluxation, and superior migration of the odontoid.

Question 9

What percent of patients with RAhave involvement of their cervical spine?

Answer 9

The cervical spine is affected in up to 80% of patients with RA.

Question 10

What are three abnormalities movements of the cervical spine that may manifest patients with ra

Answer 10

Atlantoaxial subluxation is the abnormal movement of the C1 cervical vertebra (the atlas) on C2

Question 11

What Atlantis cervical subluxation

Answer 11

Atlantoaxial subluxation is the abnormal movement of the C1 cervical vertebra (the atlas) on C2 (the axis)

Question 12

What abnormalities can lead to atlanto-axial subluxation

Answer 12

Normally, the transverse axial ligament holds the odontoid process, (also referred to as the dens), which is the superior projection of the vertebra of C2, in place directly behind the anterior arch of C1. With destruction of the transverse axial ligamentbyRA,movementoftheodontoidprocessisnolongerrestricted.Astheneck is flexed and extended, the C1 vertebra can sublux on the C2 vertebra. This can result in impingement of the spinal cord, placing it at risk for damage. (

Question 13

What is the degree atlanto Excel subluxation measured what is this measurement called

Answer 13

Subluxation of C1 on C2, referred to as atlantoaxial subluxation, can be quantified by a measuring the distance between the back of the anterior arch of C1 and the front of the dens or odontoid. This distance is referred to as the atlas-dens interval. (

Question 14

What test is used to determine the atlas dance interval

Answer 14

Subluxation of C1 on C2, referred to as atlantoaxial subluxation, can be quantified by a measuring the distance between the back of the anterior arch of C1 and the front of the dens or odontoid. This distance is referred to as the atlas-dens interval. (

Question 15

What degree of Motion between the atlas and then or what atlas dance interval is the patient considered to be at risk of spinal cord injury

Answer 15

Subaxial subluxation is the subluxation of 15% or more of one cervical vertebra on another at any level below C2. Subaxial subluxation most commonly occurs at the C5-C6 level. Patients with subaxial subluxation are at risk for spinal cord impingement with neck movement. Minimal neck movement is recommended in these patients.

Question 16

In the case of pure transverse ligament disruption does flexion or extension increase the atlas dance interval

Answer 16

In a situation in which the transverse axial ligament is disrupted, extension of the neck minimizes the atlas-dens interval and increases the safe area for the spinal cord. Conversely, flexion of the neck increases the atlas-dens interval and decreases the safe area for the spinal cord, making flexion a more frequent risk position. Still, rheumatoid arthritis affects more than just the transverse axial ligament; therefore, all neck movements in patients with rheumatoid arthritis have to be evaluated carefully as extension of the neck can also lead to problems

Question 17

If a patient is asymptomatic with neck flexion and extension preoperative can the anesthesiologist be reassured of an atlas dance interval of less than 4 mm

Answer 17

Patients with rheumatoid arthritis can be asymptomatic with neck flexion and extension preoperatively while awake, and still have an atlas-dens interval of greater than 4 mm and be at risk for cervical spine injury. These patients are able to compensate for their cervical spine instability through local muscle. Once anesthetized and the muscles are relaxed, atlantoaxial subluxation may occur. Therefore the anesthesiologist should not be falsely reassured by asymptomatic flexion and extension in the awake patient.

Question 18

What is stub axle subluxation what is it clinical significance

Answer 18

Subaxial subluxation is the subluxation of 15% or more of one cervical vertebra on another at any level below C2. Subaxial subluxation most commonly occurs at the C5-C6 level. Patients with subaxial subluxation are at risk for spinal cord impingement with neck movement. Minimal neck movement is recommended in these patients

Question 19

What is superior migration of the odontoid what are the potential clinical manifestations

Answer 19

Superior migration of the odontoid is a condition where an intact odontoid process projects up through the foramen magnum and into the skull. This occurs because of inflammation and bone destruction that results in cervical spine collapse with sparing of the odontoid process. This can occur because not all areas of the cervical spine are equally affected in any given patient. If the odontoid is spared, the intact odontoid can impinge on the brainstem and patients may suffer neurologic symptoms including quadriparesis or paralysis. (

Question 20

What surgical treatment for superior migration of the odontoid

Answer 20

Surgical treatment for superior migration of the odontoid involves removal of the odontoid to decompress the spinal cord and brainstem. A complicated surgical procedure, referred to as a transoral odontoidectomy, may be performed to accomplish this and involves an incision in the posterior pharyngeal wall, followed byremovalofthearchofC1andthenremovaloftheodontoidandpannus,torelieve neurologicsymptoms.Withcompletionofthetransoralportionoftheprocedure,the cervical spine is very unstable, necessitating a posterior spinal fusion.

Question 21

What effect does rheumatoid arthritis have on the trachea

Answer 21

Although the cervical spine is affected by rheumatoid arthritis and may collapse from bone destruction, the trachea is usually spared. This results in the trachea twisting in a characteristic manner as the cervical spine collapses, only serving to increase the difficulty of intubating the trachea of these patients. Tracheal intubation aids such as a fiber optic bronchoscope, Glidescope, Airtraq, or intubating LMA should be available for assistance in endotracheal intubation of these patients should it be required

Question 22

What is the pathology of ankylosing spondylitis

Answer 22

Ankylosing spondylitis is a rheumatologic disorder in which repetitive minute bone fractures followed by healing results in the characteristic bamboo spine, disease of the sacroiliac joint, fusion of the posterior elements of the spinal column, and fixed neck flexion that is characteristic of this patient population.

Question 23

What is the hallmark neck position in patients with ankylosing spondylitis

Answer 23

Thehallmarkofpatientswithankylosing spondylitisis afused neckinflexion

Question 24

Ankylosing spondylitis is associated with which 8LA type

Answer 24

There is an association between ankylosing spondylitis and HLA-B27, although not all HLA-B27 positive patients are affected with ankylosing spondylitis. (

Question 25

What are some considerations for anaesthetic management of patients with ankylosing spondylitis

Answer 25

Patients with ankylosing spondylitis typically have a rigid cervical spine and neck fused in flexion, which makes endotracheal intubation difficult. Airway manipulation should be performed only after careful assessment, and an intubation assist device can help secure the airway. Patients with ankylosing spondylitis may also develop thoracic and costochondral involvement, which may result in a rapid shallow breathing pattern.

Question 26

What are some considerations for anaesthetic management of patients undergoing spine surgery

Answer 26

There are several considerations for the anesthetic management of patients undergoing spine surgery, and much depends on the level of the spine in which the surgery will take place, as well as the surgical approach. Preoperative assessment of the patient for underlying neurologic deficits and chronic pain issues are important. For patients in whom the approach may be thoracic, pulmonary function tests may be indicated. In general, spine surgery can be long and complex with significant blood loss and hemodynamic alterations. Intravascular access and intraoperative monitoring should be adjusted accordingly, and blood products may need to be ordered. In the event that there will be intraoperative monitoring of the spinal cord with evoked potentials, the anesthesia administered for the surgery may need to be modified so as not to interfere with the acquisition of waveforms.

Question 27

What are the various surgical approaches to spine surgery what are the clinical implication of this

Answer 27

Spine surgery may have anterior, posterior, lateral, and thoracic approaches. In some cases, two approaches may be used during the same surgery. Preoperative discussion with the surgeon is crucial: (1) to determine the surgical approach as it may influence the location of intravascular access and monitoring placement, (2) to ensure proper positioning and padding accessories, and (3) because there may be a need to provide lung isolation and one-lung ventilation. A thoracic surgical approach may involve open thoracotomy or thoracoscopic techniques. High thoracic and thoracoscopic procedures frequently require one-lung ventilation to ensure adequate visualization.

Question 28

What kind of endotracheal tubes can be employed to provide one lung ventilation for the thoracic spine surgery

Answer 28

A double-lumen endotracheal tube or a bronchial blocker can be employed to provide one-lung ventilation for thoracic spine surgery.

Question 29

What are the advantages of bronchial blockers to provide one lung ventilation for thoracic spine surgery

Answer 29

A bronchial blocker can be used with a single-lumen endotracheal tube to provide one-lung ventilation for thoracic spine surgery. An advantage of the bronchial blocker is the avoidance of the need to change the tube between different stages of the procedure or at the end of the operation. With the bronchial blocker, deflating the cuff and withdrawing the catheter back into its casing and recapping the proximal end returns the endotracheal tube to its single-lumen tube characteristics. If extubation of the trachea at the end of the surgical procedure is not indicated, the endotracheal tube does not have to be changed, thereby avoiding the issue of changing an endotracheal tube in the presence of potentially significant airwayedema. Makecertain that the PACU staff is properly educated as to the various ports of the bronchial blocker

Question 30

What new what techniques do surgeons and floor during thoracoscopy spine surgery to move the alarm from the operative field that does not require one lung ventilation

Answer 30

Some surgeons are using carbon dioxide insufflation as the sole means of moving the lung away from the surgical field even in high thoracic spine surgical procedures. This obviates the need for one-lung ventilation, and allows for the use of a single-lumen endotracheal tube for the entire procedure.

Question 31

Why is dental operative awareness a possible complication of spine surgery

Answer 31

Patients undergoing spine surgery appear to be at an increased risk for intraoperative awareness as a result of the requirement that the anesthetic technique administered to them be modified to allow for obtaining adequate intraoperative neurophysiologic monitoring waveforms to assess spinal cord integrity. Therefore, some advocate the use of brain function monitoring in these patients to help avoid intraoperative awareness.

Question 32

Is it mandatory to employ a monitor for Intraoperative awareness in patients undergoing spine surgery

Answer 32

Awareness monitoring is not a standard and, as noted in the Practice Advisory for Intraoperative Awareness and Brain Function Monitoring, a decision should be made on a case-by-case basis by the individual practitioner for selected patients (e.g., light anesthesia). There was a consensus in the advisory that brain function monitoring is not routinely indicated for patients undergoing general anesthesia as the “general applicability of these monitors in the prevention of intraoperative awareness had not been established.” In fact, Avidan and associates demonstrated that awareness is not decreased with use of brain function monitoring. The need for brain monitoring is still not clear

Question 33

Name some methods to help decrease blood loss and patients undergoing spine surgery

Answer 33

Methods to decrease blood loss in spine surgery patients include predonation, hemodilution, wound infusion with a dilute epinephrine solution, hypotensive anesthesia techniques, red blood cell salvage, positioning to diminish venous pressure, careful surgical hemostasis, and the administration of antifibrinolytics

Question 34

What pharmacologic methods exist to diminish blood loss and patients undergoing spine surgery why is a aprotinin in not

Answer 34

Medications to decrease blood loss during surgery include the antifibrinolytics aprotinin, tranexamic acid, and E-aminocaproic acid. Aprotinin, a serine protease inhibitor, effectively decreased blood loss in cardiac patients and has been demonstrated to be efficacious in patients undergoing spine surgery as well. The negative side effects of aprotinin in cardiac patients include an increased risk of myocardial infarction (MI) or heart failure by approximately 55%, nearly double the risk of stroke, increased risk of long-term mortality, and a higher death rate in patients receiving aprotinin as demonstrated in a study over a 5-year period comparing aprotinin and lysine analogs in high-risk cardiac surgery. The study was terminated early and resulted in relabeling and ultimately withdrawing aprotinin from the market so that it is no longer available. The synthetic lysine analogs, tranexamicacidandE-aminocaproicacid,havealsobeenemployedinspinesurgery as well as in patients undergoing orthopedic surgery. Tranexamic acid can be administered by an initial bolus injection of 10 mg/kg over 30 minutes followed by a continuous infusion of 1 mg/kg/hr.

Question 35

What are some considerations for patients placed in the prone position

Answer 35

Spine surgery is often performed with the patient in the prone position. Careful positioning is crucial to avoid patient injury. Movement to the prone position should be performed in a carefully coordinated manner with the surgical team. The neck should notbehyperextendedor hyperflexed but placed in the neutral position. Theendotracheal tube is positioned so it is not kinked, contact areas are padded, and the face and eyes are protected. Pressure and stretch on nerves is avoided by proper padding and avoiding any extension over 90 degrees. The abdomen needs to be hanging free to avoid increased venous pressure and thereby increased venous bleeding. The prone position alters pulmonary dynamics, so pulmonary function must be reassessed in this position

Question 36

Why is spinal cod integrity monitor during spine surgery

Answer 36

Monitoring spinal cord integrity is an important component of major surgical procedures involving distraction and rotation of the spine such asoccurs with majoranteroposterior spinal fusions and scoliosis surgery. Spinal cord monitoring is employed to detect, and hopefully reverse in a timely manner, any adverse effects on the spinal cord noted during the operative period.

Question 37

What are various methods used to monitor the spinal cord during spine surgery

Answer 37

There are a variety of methods to monitor the spinal cord during spine surgery. These include SSEPs; motor evoked potentials, including transcranial motor evoked potentials, electromyograms (EMGs), or a wake-up test

Question 38

What are the somatosensory evoked potential what part of spinal cord do they monitor

Answer 38

SSEPsaresensory evoked potential waves generated in the extremities by repetitive stimulation that propagate up through the dorsum or sensory portion of the spinal cord and into the brain, where these signals or waveforms are detected via electrodes placed over the scalp. Specific areas on the scalp coincide with the brain’s sensory areas for the upper and lower extremities and proper signal acquisition obtained over these sites indicates an intact sensory or dorsal portion of the spinal cord. The SSEP waveform generated from multiple repetitive stimulations is analyzed for its latency and amplitude (

Question 39

What changes in latency and amplitude are considered abnormal when monitoring sspp during spine surgery

Answer 39

An increase in latency of greater than 10% or a decrease in amplitude of 60% or more, as well as the inability to obtain a proper waveform or signal, may be indicative of spinal cord dysfunction or disruption. (

Question 40

What anaesthetic technique should be employed in patients being monitored with somatosensory and or motor evoked potential

Answer 40

If SSEPs alone are being monitored, an inhaled anesthetic, equivalent to a small percentage of 1 MAC, can be administered. Volatile anesthetics may interfere with signal acquisition in patients monitored with transcranial motor evoked potentials and may have to be discontinued, if used at all, if adequate signals cannot be obtained. Intravenous anesthetics will need to be administered in these surgical cases. While neuromuscular blockade may be used to facilitate tracheal intubation, paralysis should not bemaintainediftranscranial motorevokedpotentials are being continuously monitored. If the patient is having pedicle screws placed, then the neuromuscular blockade needs to be terminated before the EMGs are obtained so that testing can be properly performed. A small dose of ketamine canbe given inthe perioperative period as an additional ppain relief modality to provide analgesia for major surgery including spine surgery.

Question 41

What are some surgically related conditions that can interfere with spinal cord monitoring waveform acquisition

Answer 41

Surgically related conditions that can result in interference of waveform acquisition during spinal cord monitoring include direct injury or trauma to the cord or impairment of the blood supply. Distraction, rotation, excessive bleeding, and severing or clamping of arterial blood supply can result in ischemia to the cord and neurologic injury.

Question 42

During spine surgery what is the time cause skin which changes in the sacp waveforms manifest after the loss of spinal cord integrity

Question 43

What is the appropriate management of a patient during spine surgery once significant changes are noted in the spinal cord monitoring waveforms

Answer 43

Once a significant change in intraoperative spinal cord monitoring waveforms is noted, specific maneuvers should be used to restore spinal cord blood flow, such as releasing the rotation and distraction of the spine if applicable. In addition, as a result of spinal cord manipulation there may be insufficient blood supply to the spine. Therefore the mean arterial blood pressure should be increased in an effortto restore adequate blood flow to the spine. All variables such as hemoglobin, temperature, arterial carbon dioxide concentration, and arterial blood pressure should be considered. Once these are all evaluated, a wake-up test may be necessary if the waveforms do not improve.

Question 44

What area of the spinal cord is monitored by transcranial motor evoked potential

Answer 44

Transcranial motor evoked potentials allow for monitoring the patient’s spinal cord motor pathways throughout the entire procedure. Stimulation over the motor cortex of the brain generates a waveform, which is propagated down the motor pathways and detected distally in the arm or leg. This stimulation results in a characteristic waveform.

Question 45

Why might merseta muscle contraction occur during transcranial motor evoked potential monitoring what is the clinical implication of this

Answer 45

To generate transcranial motor evoked potentials, the patient cannot have residual neuromuscular blockade.

Question 46

What special precautions should be taken for patients undergoing transcranial motor evoked potential monitoring during spine surgery

Answer 46

Special precautions should be taken for patients undergoing transcranial motor evoked potentials monitoring during spine surgery. The tongue should not protrude through the teeth. Placing a bite block made of tongue depressors and gauze in the back of the mouth along the teeth line bilaterally will help prevent injury. In the prone position, any motion may allow for the tongue to slip and fall between the teeth, rendering it vulnerable to laceration. Each stimulus is associated with a masseter muscle contraction, so the patient is at risk as long as waveforms are being generated.

Question 47

How are intra-operative electron MG used to determine if pedicle screws has been placed too close to the nerve root

Answer 47

Intraoperative electromyelograms are used to determine if a pedicle screw has been placed too close to a nerve root. An electric current is sent through the screw and the electromyelogram is measured distally. If a low milliamp current can stimulate the nerve root, then the screw is too close to the nerve root. In general, a current greater than 7 mA is considered safe enough to know that the pedicle screw is not too close to the nerve root

Question 48

Can neuromuscular blockade be in effect when electron milligrams are being obtained

Answer 48

For accurate electromyelogram testing, residual neuromuscular blockade must be terminated or reversed

Question 49

How can post-operative pain be managed in a patient after spine surgery

Answer 49

Postoperative pain management may prove complicated after spine surgery because some patients may have been taking pain medications preoperatively, particularly opioids. Patient-controlled analgesia (PCA) may be effective, with the dose tailored to the patient’s needs. Some centers use ketamine as an analgesic adjunct. The use of nonsteroidal antiinflammatory drugs (NSAIDs), particularly ketorolac, needs careful consideration because it is a medication that interferes with bone formation and therefore should be avoided in patients who just underwent spinal fusion. NSAIDs may be appropriate when bone healing is not a factor. Other oral medications that are helpful may include acetaminophen, anticonvulsants (e.g., gabapentin and pregabalin), antispasmodics that work at the spinal cord level (e.g., baclofen, tizanidine), antiinflammatory medications, and opioids. (50

Question 50

What is the role of intraoperative wake up test

Answer 50

The wake-up test was traditionally used to assess spinal cord integrity in many scoliosis cases. Development of sophisticated spinal cord monitoring is now standard in many hospitals and the wake-up test is generally reserved for those situations in which monitoring is unobtainable or a significant intraoperative change in spinal cord monitoring waveforms is noted

Question 51

Name potential complications of the intra-operative wake up test

Answer 51

The intraoperative wake-up test is performed as follows: turn off all inhaled anesthetics, reverse any neuromuscular blocking drug present, and stop infusions such as dexmedetomidine, propofol, narcotics, or ketamine. If spontaneous respirations do not begin, inject naloxone, 0.04 mg at a time, to reverse any residual narcoticeffect.Thepatient’sheadshouldbeheldtoreducetheriskofself-extubation. Prior to assessing lower extremity function, there should be confirmation of upper extremity function. Patient compliance denotes adequate recovery from general anesthesia. Then,whilesomeoneisobservingthefeet,askthepatienttowigglehisor her toes. A rapid-acting anesthetic such as propofol should be ready to be administered as soon as the assessment is complete, so the patient can rapidly be reanesthetized.Ifthewake-uptestisnotsuccessfulindemonstratingadequatemotor movement, further surgical intervention may be warranted and the patient may require transport to the radiology suite for additional imaging studies

Question 52

What considerations are important at the conclusion of the of a spine procedure

Answer 52

Attheconclusionofaspineprocedure,thepatientisplacedinthe supine position.All lines andtubesaresecuredsothatintravenousline,arterialline,andairwayaccessare not lost at this crucial time. Carefully reassess the patient for hemodynamic status, intravascular fluid volume status, hematocrit, blood loss, degree of fluid and blood replacement, temperature, and the potential for airway edema. Premature extubation mustbeavoided.Also,facialedema,respiratoryeffort,theamountofpainmedication, and the presence of splinting and pain should be evaluated before extubating the trachea. After tracheal extubation, the patient may be transported to the PACU. Supplemental oxygenshould be administeredinthePACU.Electrolytes, hemoglobin, and clotting studies should be ordered as indicated.

Question 53

Which patients are at the greatest risk of postoperative Visual loss what are other possible factors that contribute to post-operative Visual

Answer 53

Although its etiology is unclear, patients undergoing prolonged spine surgery (>6hours)in the proneposition whohavelargeblood loss(>1 L)areparticularly at risk. Yet, patients with small blood loss and short procedures also have had visual loss. Perioperative factors such as anemia, hypotension, prolonged surgery, blood loss, increased venous pressure from positioning in the prone position, edema, a compartment syndrome within the orbit, and resistance to blood flow, such as from direct pressure on the eye, as well as systemic diseases such as diabetes, hypertension, and vascular disease, are all possible etiologic factors. One recent study entitled Risk Factors Associated with Ischemic Optic Neuropathy (Anesthesiology 2012;116:15-24) has reported that that male sex, obesity, use of a Wilson frame, longer cases, greater estimated blood loss, and a decreased percent of colloid are associated with an increased incidence of postoperative visual loss.

Question 54

How much of the post-operative visual loss is due to ischemic optic neuropathy

Answer 54

Ischemic optic neuropathy is a major cause of postoperative visual loss. Variations in the blood supply to the optic nerve may play a role in the development of ischemic optic neuropathy including reliance on a watershed blood supply to critical areas of the optic nerve

Question 55

What are the determinants of the ocular perfusion pressure what is the clinical implication of this

Answer 55

Ocular perfusion pressure (OPP), or the blood pressure supplying blood flow to the optic nerve, is a function of the meanarterial pressure (MAP) andintraocular pressure (IOP) such that OPP¼MAP IOP. Increases in IOP or decreases in MAP can have a negativeimpactontheocularperfusionpressure.Thepronepositionisassociatedwith increasesinintraocularpressure,whichcandecreasetheocularperfusionpressureand lead to ischemia. The prone position allows edema to develop in the orbit and this increase in venous pressure may impact arterial blood flow

Question 56

What intra-operative effective has the as a registry determined to be present in the vast majority of postoperative Visual lost patience

Answer 56

A visual loss registry has been established by the ASA to facilitate establishing the etiology of postoperative visual loss. Also, an ASA practice advisory points to ischemic optic neuropathy as the most likely cause of postoperative visual loss.Of the 93 cases reported in the registry publication, 83 resulted from ischemic optic neuropathy, with the remainder attributed to central retinal artery occlusion. Central retinal artery occlusion may be embolic in nature or the result of direct pressure on the eyeball and tends to be unilateral. Most patients in the registry were healthy and positioned prone for spine surgery. Blood loss of more than 1 L and procedures of 6 hours or longer were present in 96% of cases.

Question 57

According to the as a practice advisory regarding patients at high-risk for post-operative vision loss during spine surgery is the use of deliberate hypotension associated with postoperative visual loss

Answer 57

According to the ASA practice advisory regarding patients at high risk for postoperative visual loss during spine surgery, the use of deliberate hypotension has not been shown to be associated with postoperative visual loss.

Question 58

According to the essay practice advisory regarding patients at high risk for post-operative vision loss during spine surgery what type of fluid should be administered with crystalloid in these cases

Answer 58

According to the ASA practice advisory regarding patients at high risk for postoperative visual loss during spine surgery, colloid should be administered in addition to crystalloid to maintain intravascular volume.

Question 59

According to the essay practice advisory regarding patients with high-risk for post-operative visual loss during spine surgery is there at the find transfusion trigger at which the risk of postoperative Visual loss is eliminated

Answer 59

According to the ASA practice advisory regarding patients at high risk for postoperative visual loss during spine surgery, there is no defined transfusion trigger at which the risk of postoperative visual loss is eliminated

Question 60

According to the essay practice advisory regarding patients at high risk for postoperative visual loss during spine surgery how should the patient’s head and the operator room table be positioned when patient is prone

Answer 60

According to the ASA practice advisory regarding patients at high risk for postoperative visual loss during spine surgery, when in the prone position the patient’s headshouldbepositionedlevelwithorhigherthantheheartwhenpossible. Also, when possible, maintain the head in a neutral forward position without significant neck flexion, extension, lateral flexion, or rotation. (

Question 61

What neurological postoperative complications have been noted in patients undergo surgery in the sitting position

Answer 61

Postoperative complications that have been notedinthepatient undergoingsurgery in the sitting position are rare but significant and devastating. These neurologic complications include stroke, ischemic brain injury, and vegetative states

Question 62

When devastating neurological postoperative complications or Care after surgery in the sitting position what is the implicated cause

Answer 62

Whendevastatingneurologicpostoperativecomplicationsoccuraftersurgeryinthe sitting position, the implicated cause is a decrease in cerebral perfusion pressure resulting in insufficient blood supply to the brain

Question 63

Is the systemic arterial blood pressure at the level of the heart the same as that at the level of the circle of Willis when patients are anaesthetised and placed in the sitting position

Answer 63

No,the systemic arterialblood pressure isnotthe same atthe level oftheheartasitis at the level of the circle of Willis when patients are anesthetized and placed in the sitting position. This is due to the arterial blood pressure gradient that develops between the heart and brain in this position

Question 64

What calculation more accurately determined the arterial blood pressure at the level of the circle of Willis when one known their arterial blood pressure at the level of the heart when patients are anesthetized and placed in the sitting position

Answer 64

When patients are anesthetized and placed in the sitting position, one can more accurately determine the arterial blood pressure at the circle of Willis through the following calculation: for each centimeter of head elevation above the level of the heart there is a decrease in arterial blood pressure of 0.77 mm Hg. Therefore, arterial blood pressure measured at the level of the heart is not the blood and perfusion pressure at the brain. Indeed, a 20-cm difference in height between the heart and the circle of Willis calculates to approximately a 15- to 17-mm Hg gradient.

Question 65

What superficial landmark correlates with the Circle of Willis

Answer 65

A convenient point for measuring height difference between the heart and brain is the external auditory meatus, which is at the same level as the circle of Willis. Even so, there is still a significant amount of brain tissue above this level.

Question 66

What is the potential risk of hypertension in patients that are anesthetized and placed in the sitting position

Answer 66

When patients are anesthetized and placed in the sitting position, the mean arterial blood pressure should be maintained to avoid decreases in the cerebral perfusion pressure and to potentially avoid devastating neurologic injury. Thus, hypotension inthesepatientsshouldbeavoided.Thisisparticularlytrueintheelderlyorinpatients withchronic hypertension inwhomthecerebralautoregulatory curveisaltered.

Question 67

Name several factors that predispose a person to a hip fracture

Answer 67

Factors predisposing a person to a hip fracture include medical comorbidities, osteoporosis, lower limb dysfunction, visual impairment, increasing age, Parkinson’s disease, previous fracture, stroke, female gender, dementia, institutionalized patients, excess alcohol or caffeine consumption, cold climate, and use of psychotropic medications.

Question 68

What is the mortality rate associated with hip fractures

Answer 68

Mortality rates can range up to 14% to 36% in the first year after fracture

Question 69

How do comorbidities in the patient with a hip fracture affect their postoperative outcome

Answer 69

Medical status affects morbidity and mortality. One example is the number of comorbidities from which the patient suffers, as in one study the presence of four to six comorbidities is associated with increased mortality rate when compared to patients with less comorbidity. Roche and associates, in studying 2448 patients, reported that the presence of three or more comorbidities was a strong preoperative risk factor with the postoperative development of chest infection or heart failure being associated with a high mortality rate. White and associates reported that ASA I and II patients had mortality rates equal to age-matched control subjects, but ASA III and IV patients had higher mortality rates (49% vs. 8%) after a hip fracture. Moran and colleagues, in a study of 2660 hip fracture patients with an overall mortality rate of 9% at 30 days, 19% at 90 days, and 30% at 12 months, noted that healthy patients did well as long as surgery was performed within 4 days. Patients with comorbidities had a nearly 2.5 times increased mortality rate at 30 days as compared with healthy patients

Question 70

Does it make sense to delay surgery in a patient with fractured hip and significant comorbidities to improve the patient’s medical status prior to surgery

Answer 70

Generally, when significant comorbidities that need correction exist, patients benefit from a delay in surgery while their medical status improves. The mortality rate in high-risk patients in one study decreased from 29% to 2.9% when time was taken to correct physiologic abnormalities. This was also demonstrated by Kenzora and co-workers, who noted a higher mortality rate (34% vs. 6.9%) in patients who went immediately into surgery as compared to those who were delayed 2 to 5 days to improve their medical status. Also, patients admitted to the hospital immediately after fracture did better than those admitted more than a day late

Question 71

When should patients with the recent myocardial infarction and a fractured hip be scheduled for surgery

Answer 71

The management of a patient with a recent myocardial infarction (MI) and hip fracture illustrates how evaluations and management have changed. Previously, surgery was delayed up to 6 months following a myocardial infarction, but now the tendency is to risk-stratify patients based on the severity of their myocardial infarction to determine wait time until surgery. The recent MI needs to be evaluated on a risk-benefit ratio comparing the risk of surgery after a recent MI with the negative side effects of keeping a patient bed bound with its attendant risks of pneumonia,pulmonaryembolism,pain,lossofabilitytowalk,anddecubitusulcers. Factors to consider are the extent of the MI, additional myocardium that may be at risk, if the patient suffers from postinfarct angina, and the presence of congestive heart failure (CHF). Although ongoing angina or the presence of CHF may preclude early surgery, a small subendocardial MI with a minimal increase in cardiac enzymes and normal echocardiogram and stress test would allow consideration for an earlier intervention. A fractured hip usually prevents the patient from undergoing a normal exercise stress test. Therefore, if indicated, a pharmacologic stress test may be needed. (

Question 72

What are some considerations for the anaesthetic management of patients undergoing hip surgery

Answer 72

Considerations for the anesthetic management of patients undergoing hip surgery include the patient’s intravascular fluid volume status and the potential for significant perioperative blood loss, patient positioning and proper padding on the fracture table, maintaining normothermia, and whatever additional comorbidities may be present as these patients are typically elderly.

Question 73

Does choice of anaesthetic technique spinal or general anaesthesia play a role in the outcome of patients who are fractured their hip

Answer 73

For patients undergoing hip surgery, there is no clear advantage of one anesthetic technique over another. Therefore, choice of spinal or general anesthesia should be made on a case-by-case basis taking the patient’s specific medical issues into consideration. (5

Question 74

What are the pros and cons of regional or general anaesthesia in patients with fractured hip

Answer 74

Although no one anesthetic technique has proven to be superior, the pros and cons of both spinal and general anesthesia must be considered when choosing the anesthetic technique for a given patient. Advantages of regional anesthesia, such as provided by a spinal anesthetic, are that (1) it avoids endotracheal intubation and airway manipulation and the medications that need to be administered toaccomplish this, (2) it decreases the total amount of systemic medication the patient receives throughout the procedure, and (3) it may play a role in decreasing the risk of thromboembolism. The vasodilatory effect of the spinal anesthetic may help the patient with CHF. However, intravascular fluid still should be given cautiously because CHF may worsen as the intravascular vasodilatory effect of the spinal anesthesia recedes. General anesthesia, in contrast, is easy to administer, particularly in patients in whom movement and positioning for a regional anesthetic may be painful. In addition, in a patient who may be hypovolemic, general anesthesia may be preferred to avoid a precipitous decrease in arterial blood pressure that may occur as a result of the decrease in systemic vascular resistance that accompanies regional anesthesia. (

Question 75

How are the elderly affected by the use of narcotics in the perioperative period

Answer 75

The dose and frequency of pain medication given to elderly patients in the perioperative period may need to be decreased, and should be given cautiously because of an increased circulation time, and the cumulative effect of administered opioids may become evident when not expected.

Question 76

Use of ethyl methylmethacrylate cement is associated with what side effect

Answer 76

The use of methylmethacrylate cement is associated with cardiopulmonary side effects such as hypoxia, bronchoconstriction, hypotension, cardiovascular collapse, and even death.

Question 77

What is the etiology of the systemic reaction to methylmetharystal cement

Answer 77

The systemic reaction to methylmethacrylate cement may result from the liquid methylmethacrylate cement monomer itself, which is used in producing the cement for cementing the prosthesis, or may be due to air, fat, or bone marrow elements being forced into the circulation. The higher the liquid content of the liquid monomer in the mix with the polymer methylmethacrylate cement at the time of insertion, which occurs from not adequately mixing or not waiting long enough for mixing to occur, the more frequently side effects are noted.

Question 78

Which patients are at high risk for the systemic reaction to methylmethacrylate cement

Answer 78

Patients who are at high risk for a reaction to methylmethacrylate cement include those who are hypovolemic at the time of cementing, hypertensive patients, and patients with significant preexisting cardiac disease.

Question 79

What is an appropriate tourniquet inflation pressure for lower extremity surgery

Answer 79

In the lower extremity surgery,the tourniquet is inflated to approximately 100 mmHg above the systolic blood pressure, as this will prevent arterial blood from entering the exsanguinated limb

Question 80

What is the upper limit of tourniquet time before it should be deflated

Answer 80

As tourniquets render the limb ischemic, there is a limit to inflation time before the ischemia can result in permanent limb damage. The safe upper limit of ischemia time is considered to be 2 hours. The surgeon should be informed of tourniquet inflation time at 1 hour and then as the tourniquet approaches the 2-hour limit so it can be deflated in a timely manner.

Question 81

If tourniquet time exits 2 hours and the procedure is not completed then the tourniquet should be deflated for how long before it is reinflated and why

Answer 81

If the total tourniquet time will exceed the 2-hour limit, the tourniquet should be deflated at 2 hours for a period of at least 15 to 20 minutes before it is reinflated. This will allow for the “wash-out” of acidic metabolites from the ischemic limb as the limb is reperfused with oxygenated blood. Recirculation of the ischemic limb with release of the tourniquet is noted by a decrease in blood pressure and an increaseinend-tidalcarbondioxideastheacidproductsrecirculate.Thehypotension usually responds to intravascular fluid administration and vasopressors if necessary.

Question 82

What are some complications associated with tourniquet use

Answer 82

Complications associated with tourniquet use include nerve damage, vessel damage especially in patients with atherosclerosis, pulmonary embolism, and skin damage. One source of skin damage is the antiseptic prep solution, if it is allowed to seep under the tourniquet and tourniquet padding at the time of skin prep, causing a chemical burn. Additional concerns at the time of tourniquet deflation are pulmonary embolism and a decrease in core temperature as the isolated extremity is reperfused.

Question 83

When does the major amount of blood loss occur during total knee replacement surgery

Answer 83

During total knee replacement surgery a tourniquet is used, and in the operating room blood loss is usually not significant. However, if much blood loss occurs into drains in the PACU, hypotension may result. Some surgeons do not deflate the tourniquet until the wound is closed and the dressing is on the patient. In this situation blood loss is usually less but there is a risk of bleeding

Question 84

What are current recommendations for performing neuraxial block in patients who receive enoxaparin

Answer 84

Consensus statements from the American Society of Regional Anesthesia and Pain Medicine (ASRA) addressed the issue. Recommendations included waiting at least 10 to 12 hours before neuraxial needle placement in a patient who received a preoperative dose of enoxaparin.

Question 85

When can redosing of enoxaparin ok after removal of an epidural catheter

Answer 85

Consensus statements from the American Society of Regional Anesthesia and Pain Medicine recommend waiting 2 hours prior to dosing enoxaparin after an epidural catheter is removed. Patients on warfarin should have their catheter removed only when the international normalized ratio (INR) is below 1.5, and care should be taken to avoid other anticoagulants and antiplatelet medications when low-molecular-weight heparin is being used and an epidural catheter is in place.

Question 86

What are the current recommendations for performing neuraxial in patients taking clopidogrel

Answer 86

Current recommendations in the ASRA Practice Advisory, Anticoagulation, 3rd edition, 2010, suggest that clopidogrel be discontinued for 7 days prior to performing a neuraxial block. However, the article quotes labeling as recommendingthis while the PDRsection for clopidogrel actually recommends that for elective surgery it only be discontinued for 5 days. The executive summary for the Anesthetic Management of the Patient Receiving Antiplatelet Medication, as part of the third edition, states, “On the basis of labeling and surgical reviews, the suggested time interval between discontinuation of thienopyridine therapy and neuraxial blockade is 14 days for ticlopidine and 7 days for clopidogrel. If a neuraxial block is indicated between 5 and 7 days ofdiscontinuation of clopidogrel, normalization of platelet function should be documented.” In patients who need to be maintained on clopidogrel or who have not discontinued it for an adequate time period, other anesthetic techniques should be considered. The guidelines for some of the antiplatelet medications will probably undergo revision as physicians gain experience with the use of medications such as clopidogrel in the perioperative period