Exam 3 Flashcards
What is a significant risk for poor outcomes after ortho surgery
Older age
What risks were addressed by the Surgical Care Improvement Project (SCIP)
Surgical site infection
Postop thromboembolism
Periop glucose management
Maintenance of normothermia
What is the timing for Ancef and Vancomycin
Ancef: within 1 hour of incision
Vanc: within 2 hours of incision
What are three things that are used to prevent surgical site infection
Sterile technique
Antibiotic irrigation
Antibiotic coated dressings
What makes older patients at increased risk for respiratory complications following orthopedic surgery
Decreased arterial O2 tension
Increased closing volumes
Decreased (around 10%) forced expiratory volume
What are 4 considerations for respiratory complications with ortho surgery
Elderly are at the highest risk
High rate of obesity and OSA
STOP-bang questionnaire and prudent postop management for OSA
Embolization of bone marrow debris to lungs after athroplasty
Who has a higher risk of periop myocardial morbidity and mortality
Older patients
What contributes to cardiac complications of ortho surgery
Systemic inflammatory response syndrome
Significant blood loss and fluid shifts
Stress response
What cardiac changes does the stress response from ortho surgery result in
Tachycardia
Hypertension
Increased o2 demand
Myocardial ischemia
What is a common complication seen in older patients after ortho surgery
Delirium
What factors influence an elderly patient’s development of delirium
Increased LOS
Poor functional recovery
ETOH
Pre-op dementia
Psychotropic medications
Multiple comorbid conditions
What are intraop risk factors for neurologic complications
Hypoxemia
Hypotension
Hypervolemia
Electrolyte imbalances
Pain
Benzos
Anticholinergic meds
What is the purpose of pneumatic tourniquet
Relatively bloodless field
Minimize blood loss
Identification of vital structures (improved visualization)
what is the max amount of time a tourniquet should be applied
Two hours
Necessary pressure for tourniquet in upper extremity
70-90 mmHg higher than SBP
Necessary pressure for tourniquet in lower extremity
Twice the patient’s SBP
How long does it take for abolition of somatosensory evoked potentials and nerve conduction to occur from pneumatic tourniquet
Within 30 min
What happens when tourniquet is inflated for >60 minutes
Pain and hypertension
What happens when tourniquet is inflated for >2 hours
Postoperative neuropraxia
What are the consequences of acid metabolites (thromboxane) being released into central circulation upon tourniquet deflation
Transient:
Fall in core temp
Metabolic acidosis
Fall in central venous oxygen tension
Fall in pulmonary and systemic arterial pressures
Increase in end tidal Co2
Which fibers are responsible for burning/aching pain
Unmyelinated C fibers
Which fibers are responsible for pinprick, tingling, and buzzing sensations
Myelinated A-delta fibers
What can be added to LA solutions for tourniquet pain
Opioids, ketorolac, melatonin, clonidine, precedex
Protein binding, clearance, half life of TXA
Minimally protein bound
Half life 2-3 hours
Cleared by kidneys
Dose of TXA
1 gram in 50ml of any crystalloid over 5-10 minutes, 5-20 minutes prior to incision
Side effects of txa
Minimal - nausea, vomiting, diarrhea
Contraindications of TXA
Clotting disorders
Acquired defective color vision
Subarachnoid bleed
Active clotting
Hypersensitivity to TXA
Relative contraindications to TXA
History of vascular occlusive events
Taking procoagulant
Prescription hormonal contraception
WHat should the BP be for deliberate hypotension
SBP between 80-90 or MAP between 50 and 65 in people without HTN
or
30% reduction of baseline MAP in patients with HTN
What patients should deliberate hypotension not be used in
history of cardiac, cerebrovascular, renal, or hepatic disease, or severe PVD
When is deliberate hypotension contraindicated
pts with uncorrected hypovolemia and severe anemia
What is a potential problem with deliberate hypotension
Vision loss
Which ortho surgeries have the highest incidence of thromboembolism such as DVT and PE
Pelvic fracture, hip fracture, total knee replacement
What is the leading cause of morbidity and mortality after orthopedic surgery
Thromboembolic events
How long should ortho patients receive DVT prophylaxis
up to 35 days post op
Risk factors for DVT/PE
advanced age, cancer, bed rest, prothrombotic conditions (factor V leiden), and prior DVT/PE
3 Major features of fat embolism syndrome
Respiratory insufficiency
Cerebral involvement
Petechial rash
5 Minor features of fat embolism syndrome
Pyrexia
Tachycardia
Retinal changes
Jaundice
Renal changes
Lab features of fat embolism syndrome
Fat microglobulinemia (required test for confirmation)
Anemia
Thrombocytopenia
High erythrocyte sedimentation rate
What are the consequences of acute extremity compartment syndrome
Infection
Muscle necrosis
Contractures
Nerve injury
Chronic pain
Amputation
Death
What are most diagnoses of compartment syndrome related to
Fractures, mostly in the lower leg
What is the most common fracture site associated with compartment syndrome
Tibial diaphysis: it is frequently injured and the fascial space is already tight
What are the 5 Ps of compartment syndrome
Painful onset
Pallor
Paresthesia
Paralysis
Pulselessness
Normal compartment pressures
Below 10 mmHg
When does significant injury occur from compartment syndrome
When absolute intracompartmental pressure exceeds 30-50
What is the definitive diagnostic tool for compartment syndrome
Intracompartmental pressure monitoring (sensitivity 94%)
how long should fasciotomy remain open for
at least 48 hours
How are crush injuries treated
adding hyperbaric O2
What is the main consequence of sitting/beach chair position
Cerebral hypo-perfusion
Where should bp be measured in sitting/beach chair position
At the level of the brain
Complications of beach chair/sitting position
hypotension/bradycardia
air embolism
pneumothorax
cerebral hypoperfusion
What position gives better limb stability during elbow surgery
Prone
What provides greater stability while traction is applied using either weights and counterweights
Fracture table
What are the benefits for the patients of arthroscopy
Reduced blood loss
Less postop discomfort
Reduced length of rehab
Complications from arthroscopy
Subcutaneous emphysema
Pneumomediastinum
Tension pneumothorax from shoulder arthroscopy
Patient positioning complications from arthroscopy
Inadvertent extubation
Eye or corneal injury
Visual loss from prone position
Nerve injury
What is the most desirable intervention for tension pneumo
Chest tube
How is needle compression done for tension pneumo
14 to 18 gauge iv angiocath inserted at the 2nd or 3rd intercostal space anteriorly
OR
the 4th or 5th intercostal space laterally
Advantages of regional (spinal) anesthesia for hip fracture
Avoids endotrachial intubation, airway manipulation, and medications that go along with that
Decreases total amount of systemic medication patient receives
May decrease risk of thromboembolism
Vasodilatory effect may help the patient with CHF
What is a cause of acute mortality from pelvic fractures
Retroperitoneal bleeding
What are common injuries accompanying pelvic fracture
Bladder and urethra
What is a significant risk associated with pelvic fractures
DVT and PE
Periop complications of femur fractures
MI, dysrhythmias, DVT, pulmonary embolism, delirium
Treatment of displaced femoral neck fracture
Replacement
Treatment of intertrochanteric/subtrochanteric fracture
Plates, screws, nailsat
Treatment of nondisplaced femoral neck fracture
Closed reduction or percutaneous pinning
What is the most common fracture in younger trauma patients or elderly patients with degenerative arthritis of the knee
Tibial plateau or proximal tibia fracture
What must you monitor for with a tibial fracture
Compartment syndrome
Preferred anesthetic techniques for tibia fractures
GA or spinal. Regional blocks for pain control if no compartment syndrome
What type of regional blocks are appropriate for tibia fracture
Popliteal fossa
Sciatic
Femoral
Adductor canal
What type of anesthesia is appropriate for upper extrem. fractures
GA, regional, or combo.
Brachial plexus block, interscalene
What is the purpose of arthroplasty
Return motion and function of the joint and restore the controlling function of the surrounding soft tissues
What are the goals of arthroplasty
Pain relief, stability of joint motion, correction of the deformity
What are two risks of total knee arthroplasty
Thromboembolism
Bone cement implantation syndrome
Anesthetic technique for TKA
GA and regional
What blood loss can be expected from the femur
High blood loss of 500-1000ml
Highly vascular
What surgery carries a high risk for venous thromboembolism including DVT and PE
Total Hip Arthroplasty
Significant Risk factors for bone cement implantation sydrome
Pre-existing CV disease
Pre-existing pulmonary HTN
ASA class 3 or higher
Surgical technique (cemented hip arthroplasty)
Pathologic fracture
Trochanter fracture
Long-stem arthroplasty
Clinical features of bone cement implantation syndrome
Hypoxia
Hypotension
Cardiac arrhythmias
Increased pulmonary vascular resistance
Unexpected loss of consciousness
Cardiac arrest
What is the first indication of clinically significant BCIS under GA
A fall in ETCO2 concentration
What are early signs of BCIS is awake/sedated patients with regional
dyspnea and change in consciousness
What is the treatment for BCIS
Increase fio2 to 100%
Treat like right heart failure - aggressive fluid resuscitation and treat hypotension with alpha-agonists (phenylephrine)
What is there a high incidence of with shoulder surgery
PONV
Pain
Long recovery time
There is also potential for damage to major vascular structures resulting in major blood loss
Position for total shoulder arthroplasty
Lateral decubitus
or
modified Fowler (beach chair)
What is an important risk to be aware of for shoulder arthroplasty
Potential for inadvertent extubation from patient positioning or from surgical manipulations near the patient’s head and neck
Anesthetic management for total shoulder arthroplasty
GA and regional combo
interscalene block
Supraclavicular block
What are consideration for hsoulder arthroplasty
Potential for cervical spine injury if excessive stretch or head becomes dislodged during manipulations.
Carefully monitor eyes for pressure.
What is used for virtually all surgical procedures of hand and forearm
pneumatic tourniquet
What anesthesia techniques can be used for forearm and hand surgery
brachial plexus blockade, iv regional block, or local with sedation for cases <1 hour.
GA if a longer, more complex case, comminuted fractures, reconstruction of vascular and nerve structures
Posterior tibial nerve:
Sensation to the plantar surface
Saphenous nerve:
Innervates the medial malleolus
Deep peroneal nerve:
Supplies interspace between great and second toes
Superficial saphenous nerve:
Supplies dorsum of foot and 2nd through 5th toes
Sural nerve:
Supplies the lateral foot and lateral 5th toe
What are the 2 most common reasons hospitalization after ambulatory surgery
PONV and pain
Techniques for smooth emergence and preventing hematomas for extra thoracic surgery
Stable BP or slight hypotension
Prevent PONV
Lidocaine: IV, endotracheal, topical
Precedex bolus or infusion
Titrate opioids to minimize coughing and bucking
What is the head angle in semi-fowlers
30-90 degrees above horizontal plane
Where should the chin be in semi-fowlers
1-2 fingerbreadths off the chest to protect the cervical spine
What impact does semi fowlers position have on the brain
Improved venous drainage from brain
Decreased ICP
Decreased cerebral perfusion
Pulmonary impact of semi fowlers position on
Increased FRC
Increased compliance
Less access to airway
Cardiac implications of semi fowlers position
Postural hypotension
Decreased MAP, CVP, SV and CO
What nerves are impacted by semi-fowlers
sciatic
ulnar
cervical
What are the clinical manifestations of venous air embolism
Hypoxemia
CO2 retention
Increased dead space
Decreased etco2
Treatment for VAE
Flood and pack surgical site.
100% oxygen and d/c n2o
Valsava maneuver
T-burg positioning
Hemodynamic support
How do you perform valsava maneuver on vent
Increase o2 flow, close apl valve, take off vent, squeeze bag for at least 10 seconds. This increases venous pressure and slows air entry
What are common causes of pneumothorax
Breast surgery
Axillary node dissection
Nerve blocksS
S/S of pneumothorax
Absent breath sounds on affected side
Hypoxia
JVD
Decreased BP
Increase airway pressure
Increased CVP
Increased HR
Treatment of pneumothorax
100% o2, d/c n2o
Needle thoracostomy (emergent, unstable): ICS 2-MCL or ICS 4/5 - AAL
Chest tube insertion (definitive treatment if pneumo is large)
Hemodynamic stabilization
Max dose lidocaine
4.5mg/kg
total max 300mg
Max dose lido with epi
7mg/kg
Max dose bupivicaine
2 mg/kg
Total max 175 mg
Max dose bupivacaine with epi
3mg/kg
total max 500mg
Max dose ropivacaine
3mg
total max 200mg
What is the result of delayed systemic absorption for tumescent anesthesia
long lasting and less toxic than other LAs
Preliminary max safe dosages for tumescent anesthesia
28mg/kg without liposuction
45 mg/kg with liposuction
When are there peak serum concentrations of tumescent anesthesia
12-16 hours after injection
What drugs should be avoided in treatment of LAST
Vasopressin
Ca channel blockers
Beta blockers
Sodium channel blockers
LAs
Any negative inotrope
What potentiates LAST
hypoxia and acidosis
Normal IOP
10-22 mmHg in the intact normal eye
What can a sustained increase in IOP during anesthesia cause
Acute glaucoma
Retinal ischemia
Hemorrhage
Permanent visual loss
What can cause increased IOP
Straining, retching, or coughing during induction increases venous pressure and can increase IOP by 40 mmHg or more
What is the effect of hypoxemia and hypoventilation on IOP
Increase IOP
What is the effect of hyperventilation and hypothermia on IOP
Decrease IOP
What is a miosis-inducing anticholinesterase that interferes with the metabolism of succinylcholine
Phospholine iodide
Causes prolonged paralysis following a single dose of succ
Why is topical anesthesia not always appropriate for eye surgery
It provides a lesser degree of analgesia and no akinesia of ocular muscles or eyelids
How can you prevent systemic absorption of eye drops
Have pt close eyes for 60 seconds
Avoid blinking
Block the tear outflow canal by placing index finger over the medial canthus after the eye is closed
What cranial nerves are anesthetized by a retrobulbar block
III
IV
V
VI
VII
Where is a retrobulbar and peribulbar block performed
Orbital epidural space
What are the risks of retrobulbar block
Optic nerve injury
Brainstem anesthesia
Retrobulbar hemorrhage
Which occurs first in ocular block, analgesia or akinesia
Analgesia precedes akinesia of muscles
When can effectiveness of retrobulbar and peribulbar blocks be evaluated
Retrobulbar: after 2 minutes
Peri: after 10 minutes
If you have akinesia of the muscle do you have analgesia?
It is assumed yes, but not guaranteed
What is the rarest but most devastating complication of ocular blocks
Ocular explosion
Indications for GA in ocular surgery
Pediatric patient
Lack of patient cooperation
Severe claustrophobia
Inability to communicate
Inability to lie flat
Open-eye injuries
Procedures with durations greater than 2 hours
Classes of medications for regional blocks during ocular surgery
benzos, narcotics, nonbarbiturates
What is the danger of having a sleeping patient during ocular block
Sleeping patients can snore and have sudden head movements upon awakening
What can cause expulsion of the eye contents
Choroidal hemorrhage - occurs when a vessel in the vascular choroidal layer of the eye ruptures, bleeding into the closed cavity and creating an acute rise in IOP
What can cause an acute increase in IOP above 40 mmHg during induction
Coughing and retching
Which induction agents lower IOP
Propofol and etomidate
Inhalational agents for infants and children
What is the effect of nondepolarizing agents on iop
Decreases IOP
What can cause EKG changes during ocular surgery
Oculocardiac reflex
What do patients undergoing eye muscle surgery have an increased incidence of
Malignant hyperthermia
Postop nausea
What helps to attenuate the increase in IOP caused by laryngoscopy
IV lidocaine 1/5-2 mg/kg given 1-1.5 minutes before
Ophthalmic complications during regional and general anesthetics are most likely caused by:
Patient movement
What can cause extrusion of globe contents and jeopardize vision regarding traumatic eye injuries
Increased IOP due to a tightly applied face mask, laryngoscopy, intubation, coughing/retching, bucking
How do most complications of regional ocular anesthetics occur
From direct traumatization of the orbital vessels, globe, and optic nerve
What is the initial intervention if the oculocardiac reflex is suspected
request that the surgeon release traction or pressure
What are the signs and symptoms of globe puncture
Intraocular hemorrhage
Rapid increase in intraocular pressure with corneal edema
What is a paravertebral block
targets spinal nerves on the side of the injection, can be performed at both thoracic and thoracolumbar levels; sympathetic fibers are blocked with less hemodynamic response than epidurals
What is the level of block required for breast surgery
C7-T6
What is the most effective pain management technique for breast surgery
paravertebral block
What decreases epidural spread during paravertebral block
inject slowly, small volumes, and at low pressure
What are complications of paravertebral blocks
Pneumothorax
Epidural spread (common, up to 40%)
Vascular, epidural, subarachnoid injection
Postdural puncture headache
Pecs 1 block:
Medial and lateral pectoral branches of brachial plexus
Pecs II block:
Long thoracic nerve
Lateral cutaneous branches of thoracic intercostal nerves (T2-T4)
Indicated for more extensive procedures involving chest wall and axilla
Landmarks for Pecs blocks
Pectoralis major
Pectoralis minor
Serratus anterior
Thoracoacromial artery (pectoral branch)
Serratus plane block:
Increases intercostal coverage from T2-T9
More lateral than Pecs II block.
Overlies 5th rib at the midaxillary line.
No coverage to pectoralis muscle
Landmarks for Serratus block:
Latissimus dorsi muscle
Serratus anterior muscles
Thoracodorsal artery
Complications of Pecs block
Large volume of LA causes risk for LAST.
Risk of vascular injection due to pectoral branch of thoracolumbar artery lying within the interfascial plane of the Pecs I injection.
Pneumothorax - intercostal space and pleura are just inferior to serratus anterior muscle
