Nicole Weiss, MD March 23, 2012

Neuromonitoring &/or Wake-Up Test Significant Blood Loss Requiring Transfusion Postoperative Vision Loss Spinal Trauma- Cervical Spine Injury & Spinal Shock Postoperative Airway Compromise Venous Air Embolism Preserving Spinal Cord Perfusion Bronchial Blocker to Assist in Anterior & Lateral Thoracic Procedures

A 16 y/o female is undergoing instrumentation and fusion for scoliosis.  What anesthetic would you pick for this case & why? In the middle of the case, motor evoked potentials are lost on the right side.  What is the next step?

1. One Hour 2. Two Hours 3. Three Hours 4. Four Hours

1. Propofol & Remifentanil 2. Propofol & Sufentanil 3. Desflurane & Sufentanil 4. Desflurane & Remifentanil

Etiology of the loss of motor function during surgery  Trauma, Ischemia, Hematoma, Compression After three hours of critical ischemia there is usually no neurologic recovery When patients awaken paraplegic there is little chance of full neurologic recovery Prevention: Neuromonitoring & The Wake-Up Test

Preserves SSEPs & MEPs while maintaining an adequate depth of anesthesia Allows for a quick wake-up to assess motor function Ensures that the patient can be kept comfortable even during a wake-up test

RCT published in 2004 Anesthesia & Analgesia 54 patients assigned to one of the following regimens:  Propofol & Remifentanil  Propofol & Sufentanil  Desflurane & Remifentanil

Discontinue all anesthetics Reverse neuromuscular blockade If spontaneous respirations don’t occur, administer naloxone (in low increments) Stabilize head to prevent extubation Ensure upper extremity movement prior to lower extremity movement Be ready to re-anesthetize

52 y/o female with h/o of chronic low back pain admitted for a transpedicular osteotomy with a posterior approach, T12-L4. Baseline Hgb/Hct of 10/30. Initial Concerns?

Three Factors Predict Need for Transfusion  Age Greater than Fifty  Preoperative Hemoglobin Less than Twelve  Transpedicular Osteotomy Ways to Decrease Intraoperative Blood Loss  Induced Hypotension  Operative Tables (Jackson & Wilson Frame)  Antifibrinolytic  Activated Factor VII  Cell Salvage  Hemodilution

1. Tranexamic Acid 2. Aminocaproic Acid 3. Aprotinin

Aprotinin  Studies consistently show that it decreases blood loss  Withdrawn from the market after studies revealed a potential increase in mortality, perioperative renal failure, myocardial infarction and cerebral vascular accident after use  Study may have weaknesses Tranexamic Acid & Aminocaproic Acid  Studies Inconclusive

55 y/o male admitted for a lumbar spine surgery with a posterior approach. PMH is significant for peripheral vascular disease, diabetes and a prior TIA. The surgeon notes that the surgery will likely take ten hours and have an EBL of 2-3Liters. Besides the likely need for transfusion, what is your first concern?

Deliberate hypotension is associated with perioperative vision loss ? 1. True 2. False

1. Cortical blindness 2. Posterior Ischemic Optic Neuropathy 3. Acute Angle Glaucoma 4. Anterior Ischemic Optic Neuropathy 5. Retinal Vascular Occlusion 6. Expansion of a vitrectomy bubble

Proposed Risk Factors of PION Patient Factors  Male  Diabetes  Peripheral Vascular Disease Operative Factors  Prolonged Duration in Prone Position  Large EBL  Anemia  Venous Congestion of Head  Hypotension  Prolonged Use of Vasopressors  Type and Amount of Fluid Replacement  Blood Transfusion External Pressure?

ASA Practice Advisory for Perioperative Visual Loss Associated with Spine Surgery There is a subset of patients who undergo spine procedures while they are positioned prone and receiving general anesthesia that has an increased risk for the development of perioperative visual loss. This subset includes patients who are anticipated preoperatively to undergo procedures that are prolonged, have substantial blood loss, or both (high risk patients) Consider informing high-risk patients that there is a small, unpredictable risk of perioperative visual loss. The use of deliberate hypotensive techniques during spine surgery has not been shown to be associated with the development of perioperative visual loss. Colloids should be given along with crystalloids to maintain intravascular volume in patients who have substantial blood loss. At this time, there is no apparent transfusion threshold that would eliminate the risk of perioperative visual loss related to anemia High risk patients should be positioned so that their heads are level with or higher than the heart when possible. In addition their heads should be maintained in a neutral forward position when possible. Consideration should be given to the use of staged spine procedures in high risk patients.

A 27 y/o male s/p MVA is brought to the operating room for an emergent decompression for traumatic cervical spinal cord injury. What is your initial concern??  Securing the Airway

A patient with a recognized, unstable cervical spine injury has an increased risk for neurologic injury following intubation. 1. True 2. False

1. Awake Fiberoptic 2. Direct Laryngoscopy 3. Fast Track LMA 4. Glidescope Thoughts??

1. no association 2. < 30% 3. < 50% 4. < 70 % 5.< 90% During the case the surgeon asks you to modify your inspired gas concentrations to decrease the risk of a surgical site infection.

 Maintain neutral neck position  Greatest movement in the atlanto-occipital junction and the junction of the first two cervical vertebrae  If the patient has a recognized unstable cervical spine, intubation is not associated with an increased risk of neurologic deterioration  Superior Technique for Intubation?  Awake Fiberoptic, Direct Laryngoscopy, Glidescope, Fast Track LMA  All techniques are acceptable in experienced hands

Case Control Study Johns Hopkins, patients with surgical site infections compared to 104 random patients without surgical site infections Compared multiple factors, including an FiO2>50 FiO2 is a MODIFIABLE risk factor 02 vital to oxidative leukocyte processes

1. Administer FFP 2. Administer Platelets 3. Administer Cryoprecipitate 4. Dialyze the patient 5. Administer protamine

1. Direct Thromin Inhibitor 2. GIIb/IIIa Inhibitor 3. Platelet Aggregation Inhibitor 4. Fibrinolytic Agent

1. 8 hours hours hours hours hours

Direct Thrombin Inhibitor Alternative to warfarin for prevention of stroke, DVT 80% renally excreted unchanged Administered PO Does not require INR monitoring PTT is prolonged, but it is not linear and does not correlate to the level of anticoagulation Ecarin clotting time most accurate

Currently no way to fully reverse the anticoagulation  A monoclonal antibody is being developed For active bleeding  Hemostasis  Transfuse as needed  Maintain diuresis (renally cleared)  Dialyze (62% can be cleared in 2 hours)  Factor VII?  One recent case report suggests a high dose of 7.2mg/kg may have helped reverse

Half life 8 hours in a healthy patient Half life up to 17 hours in patients with renal failure Dabigatran should be stopped 1-5 days prior to surgery  Bleeding risk & type of surgery  Renal function of the patient

ASRA:  Insufficient evidence. Suggest avoidance of neuraxial techniques. German Society for Anaesthesia & Belgian Association for Regional Anesthesia:  Needle placement 8-10 hours after last dose. Delay subsequent doses 2-4 hours after needle placement American College of Chest Physicians:  No Recommendations “Although there have been no reported spinal hematomas, the lack of information regarding the specifics of block performance and the prolonged half-life warrants a cautious approach.”

Baldus, C. Can We Safely Reduce Blood Loss During Lumbar Pedicle Subtraction Osteotomy Procedures Using Tranexamic Acid or Aprotinin. Spine. 2010; 35: Barash, P. Clinical Anesthesia, 6 th ed Bitar, W. Critical ischemia time in a model of spinal cord section. A study performed on dogs. European Spine J. 2007;16: Black, Susan. Perioperative Manaement of Patients Undergoing Spine Surgery. Anesthesiology Farrokhi, M, et al. Efficacy of Prophylactic Low Dose of Tranexamic Acid in Spinal Fixation Surgery: A Randomized Clinical Trial. J. of Neurosurgical Anesthesiology.2011;23: Grottke, O, et al. Intraoperative Wake-Up Test and Postoperative Emergence in Patients Ungergoing Spinal Surgery: A Comparison of Intravenous and Inhaled Anesthetic Techniques Using Short-Acting Anesthetics. Anesthesia & Analgesia. 204;99: Jaffe, R. Anesthesiologist’s Manual of Surgical Procedures, 4 th ed. Lipincott Williams & Wilkins, Roth, S. Perioperative visual loss: what do we know, what can we do? British Journal of Anesthesia ;