Test 2: Orthopedics (pt 2/4) Flashcards
What are benefits to use of a pneumatic tourniquet?
-Relatively bloodless field during extremity surgery
-Minimize intraoperative blood loss
-Aid in identification of vital structures
-Expedite the procedure
When are tourniquets applied?
After initiation of anesthesia. Need multimodal anesthesia before the tourniquet is inflated. Will still see BP rise with use.
The ischemic pain associated with tourniquet application is similar to that of thrombotic vascular occlusion/peripheral vascular dz.
What is the timing precautions associated with duration of tourniquet application?
-Document time of inflation/deflation
-Set alarm for 60 min intervals - communicate with surgery
-Maximum of 2 hours considered safe!!
-If >2 hrs, consider deflation for 15- 20 min, then reinflate
-Pressure in which it is inflated to depends on pt’s BP and shape/size of extremity
What happens with deflation of the tourniquet?
Release of metabolic waste into systemic circulation
-Transient changes in hemodynamics or pulse ox readings (hypotension, hypoxia)
-Most of these changes resolve quickly, except in patients with extreme conditions r/t cardiac or vascular status (metabolic acidosis, hyperkalemia, myoglobinemia, myoglobinuria, and renal failure)
What are symptoms reported with tourniquet pressurization (awake patients)?
-Dull aching, which progresses to burning and excruciating pain that may require GA
-Once pain begins, it is often resistant to analgesics and anesthetic agents, regardless of anesthetic technique
What is the pain associated with C Fibers (Unmyelinated)?
-Dull, aching pain
-Small, slow-conducting, unmyelinated C fibers
What is the pain associated with A-Delta Fibers (Myelinated)?
-Pinprick, tingling, and buzzing sensations, even after deflation
-Burning, tingling pain
-Larger, faster, myelinated A Delta Fibers
What should you be sure to include with pain mgmt for tourniquets?
Regional Anesthesia (multimodal)
Which patients are at highest risk for Venous Thromboembolism (VTE)?
-Total Hip (THA)
-Total Knee Arthroplasty (TKA)
-Pelvic Fx
What is the etiology for developing Venous Thromboembolism (VTE)?
Venous stasis, hypercoagulability, vascular trauma
What are the S/Sx of a Pulmonary Embolism (PE)?
Dyspnea, chest pain, tachycardia, shock
What are the S/Sx of a DVT?
Painful swelling of extremity, fever
What are the pharmacologic recommendations to prevent VTE?
-Low molecular weight heparin (not for hip fx surgery)
-Low dose unfractionated heparin
-Adjusted-dose Vit K antagonist
-ASA
-Intermittent pneumatic compression device (IPCD) for a minimum of 10-14 days
-However, impacts RA and Neuraxial anesthesia
When should low molecular weight heparin be started?
> 12 hrs preop or >12 hrs postop
Increased risk for bleeding
What are the clinical features associated with Bone Cement Implantation Syndrome (BCIS)?
-Hypoxia, hypotension, cardiac arrhythmias, increased pulmonary vascular resistance, unexpected loss of consciousness when regional anesthesia is administered, and cardiac arrest.
-Most commonly associated with hip arthroplasty, but may occur during other procedures including Knee arthroplasty and vertebroplasty
-Estimated to occur in 2-17% of surgeries
What are the theories behind the etiology of BCIS?
-Involve the role of emboli formed during cementing and prosthesis insertion
-Several mechanisms such as histamine release, complement activation, and endogenous cannabinoid-mediated vasodilation have been proposed.
How do you manage BCIS?
-Optimize BP prior to cementing
-100% FiO2, pressure bags available for rapid IV fluid administration, IV fluid bags full or nearly full
-Vasporessors as needed
-Communicate with team!! And document time on anesthesia record
Patients with one long bone fracture have approximately a ____% chance of developing fat emboli syndrome (FES), and patients with bilateral long bone fractures have a ___% chance.
3%; 33%
Pelvic fxs also at risk
What causes the hypoxia associated with fat embolism?
The seeding of fat cells from the disrupted bone marrow into the venous circulation and eventually lodge in the pulmonary arterial circulation. The resultant pulmonary capillary obstruction leads to diffuse interstitial edema, alveolar collapse, and subsequent reactive hypoxic pulmonary vasoconstriction.
What can massive fat embolism progress to?
Macrovascular obstruction and shock
Fat Embolic Syndrome (FES) is typically seen ____ - ____ hours after injury
24 - 72 hours
What are the symptoms of Fat Embolic Syndrome (FES)?
Hypoxemia
Neurologic impairment
Petechial Rash
(!!)
What is the treatment for FES?
-Supportive Care: ET intubation and mechanical ventilation
-May benefit from corticosteroids IV (low dose methylprednisolone)
-Surgical correction/stabilization of long bone fractures ASAP may reduce risk of FES and other pulmonary complications (PNA, PE, ARDS)
What are benefits to the use of Regional Anesthesia in orthopedics?
-May reduce risk of DVT, PE, & Blood loss
-Periop pain mgmt
-May reduce chronic pain issues and opioid use disorder
What does the choice of local anesthetic depend on?
-Type of PNB
-Purpose (anesthesia or postop pain)
-Duration of anesthesia required for surgery
What are some additives to prolong regional blockade?
-Epinephrine
-Clonidine
-Dexamethasone
-Opioids
A PNB that anesthetizes the shoulder and upper arm, but has a risk of ulnar nerve sparing (not good for hand surgery)
Interscalene
A PNB that anesthetizes the entire upper arm, distal to the shoulder
-Has risk for Pneumothorax (reduce risk through the use of US)
Supraclavicular
A PNB that anesthetizes the elbow and below
-Not rly used anymore
Infraclavicular
A PNB that anesthetizes the area distal to the elbow
-Risk of vascular injection
-Must block musculocutaneous nerve separately
Axillary
What nerve has to be blocked separately with an Axillary block?
Musculocutaneous nerve because it lies outside of the vascular sheath (?)
Which lower extremity PNB anesthetizes the Hip?
Pericapsular nerve group (PENG)
-Used for anterior hip surgery
Which lower extremity PNB anesthetizes the Anterior LE and knee; medial lower leg?
Femoral/Adductor Canal (Saphenous)
Femoral is sensory & motor
Adductor Canal is just sensory
Which lower extremity PNB anesthetizes the posterior knee?
IPACK (often combined with Fascia iliaca)
Which lower extremity PNB anesthetizes the anterior LE and knee; provides analgesia for the hip?
Fascia Iliaca (often combined with IPACK)
Which lower extremity PNB anesthetizes the posterior LE, lateral side below knee, and foot?
Sciatic/popliteal
Which lower extremity PNB anesthetizes the foot?
Ankle
A minimally invasive surgical procedure performed to examine and sometimes repair damage of the interior of a joint using an arthroscope.
Arthroscopy
What are benefits of the use of arthroscopy?
-Reduced blood loss
-Less postop discomfort
-Reduced length of rehabilitation
What anesthetic technique is best for arthroscopy?
Any type will work: GA, RA, combined GA/RA, or Local blockade with sedation
-Patient selection for a given anesthetic technique is crucial
Arthroscopic procedures for lower extremity joints & upper extremity joints use what position?
Supine
Hip arthroscopy is done in what position?
Lateral decubitus or supine
What positions are used for Shoulder arthroscopy?
Lateral decubitus or Modified Fowler (beach chair) position
What are the complications associated with the use of irrigating fluid in arthroscopy?
-Fluid volume overload
-CHF, Pulm edema
-Hyponatremia if sterile water is used
-Hypothermia (fluid is room temp)
What are the complications that have been reported during shoulder arthroscopy when subacromial decompression is used?
Subcutaneous emphysema
Tension Pneumothorax
Pneumomediastinum
For every ____ cm of elevation, MAP drops by ____mmHg.
1; 0.75
What are the hemodynamic changes associated with Beach Chair position in shoulder surgery?
-Blood pooling in lower extremities = dec BP due to dec venous return
-Activation of Bezold-Jarisch reflex (Profound HOTN and Bradycardia)
What is the Bezold-Jarisch Reflex?
Profound HOTN and bradycardia when shoulder surgery is performed in the sitting position, under an interscalene block
-30% incidence
-An inhibitory reflex mediated through cardiac sensory receptors with a vagal efferent limb
How do you decrease the hemodynamic effects of beach chair position?
-Slow or incremental incline
-Adequate hydration
-Vasopressors
-Elastic stockings
-SCDs
Increase venous return to offset symptoms
