AP 1 Test 2 Flashcards
Most common Closed Claims cases
Death, Nerve damage, brain damage
“Other” Closed Claims cases
Airway injury, emotional distress, eye injury, back pain
How common are claims of awareness and what types
2% 18 awareness, 61 recall
Signs and symptoms of awareness
Hearing, sensation of paralysis, anxiety, helplessness
How many patients who have recall experience residual effects
70%
What volatile prevents recall the most
More than 0.6MAC of Iso
What is the most common claim of awareness
Females undergoing GA with no volatile
What is the most common error that leads to recall
Drug labeling and communication
What percentage of closed claims are concerned airway injury
6%
What percentage of airway injurys resulted from a difficult intubation
39%
What percentange of airway injuries were temporary
87%
How are airway injuries caused by mask ventilation
Excessive pressure damaging soft tissues
How do oral and nasal airways injure the airway
Nasal-epistaxis Oral-broken teeth, mucosal tears
How can an LMA lead to airway injury
Tip of epiglottis folded into cords Excessive lube causing laryngospasm Regurgitation Sore throat
What complications arise with intubation
Dental damage, lip injuries, sore throat, vocal cord paralysis, trauma
What percentage of patients have a sore throat when there is blood on instruments
40-65%, pain on swallowing 24-48 hrs
What can cause vocal cord paralysis
Endotracheal tube cuff, usually temporary
What injuries are associated with the glidescope
Soft palate and tonsillar injuries
What is the most frequent cause of complaints against anesthesiologist
Dental damage
Which serious dental injuries are most common
Subluxation, fracture, avulsion of teeth
How much does risk of dental damage increase with a difficult airway
20x
Which airway qualities have reported contact with teeth 90% of the time
Buck teeth and MAL3
Which teeth are at highest risk during a DL
Central incisors
What are the most common vascular injuries
Necrosis, skin slough, swelling, inflammation, infection, nerve damage, fasciotomy
What is the pathophysiology of aspiration
LES distinct from esophagus
What is barrier pressure
Difference in LES (20-30) and intragastric pressure (5-10)
What decreases LES pressure
Peristalsis, vomiting, pregnancy, achalasia, various drug
What increases intragastric pressure
Increased gastric volume, increased intraabdominal pressure
What affects gastric volume and gastric emptying
Pregnancy, labor, pain, GI disorders, renal failure, diabetes, opioids
What amount of gastric volume and pH are significant indicators for aspiration
0.4mL/kg gastric fluid, pH less than 2.5
What are the biggest risk factors for aspiration
Emergency, full stomach, obstetrics, GI obstruction, ascites, GERD, hiatal hernia
What are three disease outcomes from aspiration
Particulate-Associated Aspiration, aspiration pneumonitis, aspiration pneumonia
What can Particulate-associated aspiration lead to
Distal atelectasis
What causes aspiration pneumonia
Inhaling infected material or bacterial infection
What causes aspiration pneumonitis
Lung tissue damage b/c of aspiration of non-infective gastric fluid Desquamation of bronchial epithelium causing increased alveolar permeability Interstitial edema, reducing compliance and causing V/Q mismatch
What can prevent aspiration
Preop fasting Reducing gastric acidity/volume RSI Cricoid pressure NG tube placement
What drugs can reduce gastric acidity/volume (5)
Histamine blockers Anticholinergics Antacids PPI Antiemetics
What are major complications related to positioning
Venous Air Embolism, alopecia, backache, extremity compartment syndrome, corneal abrasion, nerve palsies, retinal ischemia, necrosis
What is the most common position for Extremity Compartment Syndrome
Lithotomy
What percentage of Closed Claims deals with eye injury
3%
What are the top causes of corneal abrasion
Facemark, import taping of eyes, decreased tear production, swelling
Who is most at risk for eye injury
Robotic prostatectomy
What is the first choice treatment for corneal abrasion
Erythromycin
What is the backup treatment for corneal abrasion
Bacitracin eye ointment QID x 48hrs
What is the biggest risk factor for Ischemic Optic Neuropathy
Spine surgery in prone position
What two arteries get occluded during IOP
Central Retinal Artery Retinal Artery Branch
How often should intermittent examinations be done to reduce chance of IOP
Every 20 minutes
What releases inflammatory agents in an Anaphylactic reaction
Basophils and Mast cells
What does an antigen interact with during an anaphylactic reaction
IgE
What two main side effects occur with a Type I hypersensitivity reaction
Urticaria and angioedema
What is different about an anaphylactoid reaction
No IgE interaction
What is the MOA for an anaphylactoid reaction
Drug directly release histamine from mast cells
What is a pretreatment for anaphylactoid reaction
Histamine antagonist, corticosteroids
What is the biggest cause of allergic reactions
Muscle relaxants - 60%
Who is most at risk for Latex allergies
Healthcare workers
What groups of patients are at risk for Latex allergies
Spina bifida, spinal cord injury, GU abnormalities
What percentage of the population is allergic to PCN (beta lactic) and what percentage is anaphylactic
2%, 0.1%
What type of reaction is Vancomycin and Redman syndrome
Anaphylactoid
What are the CV symptoms of a reaction
Hypotension Tachycardia Arrhythmia
What drug treats allergic reactions
Epinephrine
What pulmonary symptoms occur from an allergic reaction
Bronchospasm, cough, dyspnea, edema, hypoxia
What dermatological symptoms occur from an allergic reaction
Pruritis, urticaria, facial edema
What is the dose of Epi to stop an allergic reaction
0.01-0.15 IV or IM
What are methods to treat an anaphylactic reaction
stop agent, 100% oxygen, intubation, fluid load
What is the dose of diphenhydramine (benadryl) to treat an allergic reaction
50-75 mg IV
What is the dose of Ranitidine (H2 blocker)
150 mg IV
What is the dose of hydrocortisone
up to 200mg IV
What amount defines hyperkalemia
Greater than 5 mEq
How can you rule out pseudohyperkalemia
Hemolysis, Leukocytosis, Thrombocytosis
What are the 3 ways you can get hyperkalemia
Excess K+ intake, Translocation from ICF to ECF (B blockers, digitalis, aldosterone blockers, succinylcholine), decreased excretory capacity (cyclosporine, NSAIDS, ACE inhibitors, K+ sparing diuretics)
How is hyperkalemia manifested on an EKG
Peaked T waves
How is extreme hyperkalemia manifested on an EKG
Sine waves
What are cardiovascular effects of hyperkalemia
Arrhythmias, heart block, delayed conduction, ventricular standstill, peaked T waves, decreased P waves, prolonged PR interval, wide QRS, sine wave
What are the neuromuscular effects of hyperkalemia
Paresthesias (Na/K pumps), weakness, paralysis, confusion
What are 5 treatments of hyperkalemia
1) Ca2+ to stabilize cardiac membrane 2) Insulin to drive K+ back in cells and Glucose to avoid hypokalemia 3) Hyperventilation to induce alkalosis and shift K+ (increase minute ventilation) 4) Diuretics (Lasix) 5) Dialysis
Does vasoconstriction increase or decrease with hypothermia
Decrease
What are side effects of hypothermia
Myocardial ischemia, arrythmias, coagulopathy, longer duration of muscle relaxants
What does shivering do to O2 consumption, CO2 production, and cardiac output
Increase b/c heart rate increases
What is the definition of a critical incident
A human error or equipment failure that could have led to undesirable outcomes
What are the top causes of critical incidences
1) Human error (68%) 2) Equipment failure 3) Disconnection
What percentage of incidences occur from failure to inspect
22-33%
Where is local injected for a spinal
CSF of subarachnoid space (intrathecal)
Which neuraxial method requires more drug
Epidural
Which neuraxial method works more quickly
Spinal
Where is an epidural injected
Epidural space
Which neuraxial method has the chance of mixing spinal and epidural
Epidural
Which injections are used for chronic pain release
Epidural injections and indwelling spinal catheters
What are the 7 absolute contraindications for neuraxial anesthesia
Infection, patient refusal, aortic stenosis, mitral stenosis, hypovolemia, increased ICP, coagulopathy
What are the 4 relative contraindications for neuraxial anesthesia
Sepsis, uncooperative patient, neurologic deficit, spinal deformity
What are the 3 controversial contraindications for neuraxial anesthesia
Prior back surgery, can’t communicate, complicated surgery
What oral anticoagulant must be stopped with the patient having normal PT and INR
Coumadin (Warfarin), stopped days before
What are the 2 antiplatelet drugs that must be stopped 7 days before surgery
NSAIDS and Plavix [makes platelets slippery]
How long must an epidural be in place before intraop heparin is given
1 hour
How long after intraop heparin is given before an epidural can be removed
4 hours
What is an example of low molecular weight heparin
Lovenox, can’t have an hour before or after they take the catheter out
What does the vertebral canal extend from
Foramen magnum to sacral hiatus
What is the principal landmark for spinal anesthesia
L4, iliac crest
What is the principal landmark for thoracic epidurals
T7-T8 interspace, scapula
Where does the posterior superior iliac spine lie
S2
What are the 3 ligaments of the spinal canal
Supraspinous, infraspinous, ligamentum flavum
Where does an adult and infant spinal cord end
Adult L1, infant L4
What are the dermatomes for nipple and belly button
T4 nipple (C section), T10 belly button (TURP)
What does a spinal cover
Everything below pelvis
What are the motor/sensory coverages of both neuraxial methods
Spinal single shot can take out motor function Epidural can maintain motor and still take out sensory
What are the relative sizes of the nerves and what is the difficulty of blockage
Sympathetic > Sensory > Motor Motor most difficult, sensory easier but spreads more, sympathetic easiest
How can you test a sympathetic block
Bag of ice/coldness factor
Which dermatomes are the cardiac accelerators and what happens if they are blocked
T1-T4, low BP low HR
Which dermatomes determine vasomotor tone
L5-T1
What should you do if a patient is nauseous from the hypotension caused by an epidural
Lay down, maybe trendelenburg
What are the blood vessels supplying the spinal cord
One anterior Two posterior Artery of Adamkiewicz - 2/3 anterior portion of cord
What are the indications for an epidural
Primary anesthetic for belly or lower extremity Supplements general anesthesia Postop pain
What are the indications for a spinal
Lower abdomen, perineum, lower extremities
How should a patient be positioned for a midline approach
Sitting
What prodecures should a patient be positioned prone to received neuraxial block
Anorectal
What is the principle site of action for neuraxial blocks
Nerve root
What is the MOA for neuraxial blocks
Binds to nerve tissue and blocks transmission of pain signals
What does blocking posterior nerve rooms interrupt
Somatic and visceral sensory nerves
What does blocking anterior nerve roots block
Motor and autonomic outflow
Which neuraxial block must be very close to the roots anesthesized
Epidural
Which block can achieve a differential blockade
Somatic motor (sympathetic, sensory, or motor)
What does a somatic block do
Interrupt pain Abolish skeletal muscle tone
What area does a sympathetic block cover
Thoracolumber, T1-L2 Small myelinated
What area does an autonomic block cover
Craniosacral, not vagus
What are the CV effects of a neuraxial block
Decreased HR, BP, contractility Decreased tone
Where are the cardiac accelerators
T1-T4
What pulmonary effects does a neuraxial block have
Can knock out accessory muscles and possibly diaphragn via phrenic nerve (C3-C5)
What GI effects does a neuraxial block have
Vagal tone dominate (increased function)
What effect does neuraxial anesthesia have on renal function
None
What effect does neuraxial anesthesia have on urinary retention
Increases
What are the three types of spinal needles
Quinke (teardrop), Whitacre (dot), Sprotte (rectangle)
What are the 3 types of epidural needles
Tuohy (blunt tip), Crawford (thin walled), Waiss winged
What are the advantages of an epidural over a spinal
-Decreased risk of post dural headache -Segmental sensory block -Greater control over intensity of block and type -Can titrate/elongate block with indwelling catheter -Can hit all 3 spinal levels
What are the disadvantages of an epidural
-Slower onset time 10-20 min -Less dense of a block -No confirmation like a spinal (loss of resistance)
Do you need more or less volume/concentration for an epidural
More
What is a test dose for an epidural
3ml 1.5% lidocaine with epi 1:200,000
What is the amount of local per segment
1-2mL per level
What patient populations are exception for amount of epidural
Short, elderly
What are the benefits of spinal over an epidural
Shorter time, slighter amount, more intense sensory/motor block, can confirm placement by CSF
What classes of drugs can you add to a spinal block
Vasoconstrictors, opioids
What are the three levels of baracitiy affecting a spinal
Hypobaric - less dense than CSF, floats Isobaric - same, stays in place Hyperbaric - more dense than CSF, sinks
What affects the level of a spinal block
Baricity, positioning during and immediately after, concentration, site of injection
What two substances can be added to chance the baricity of a spinal
Water and glucose
Which neuraxial method risks cardiac arrest
Spinal
What causes a post dural puncture headache
Breach of dura, CSF leaks and causes decreased intracranial pressure, needle size
What are the s/s of PDPH
Photophobia, nausea
What are the 3 types of PDPH
Bilateral, frontal, retroorbital
What is the definitive treatment for PDPH
Epidural blood patch
Spinal vs Epidural injection location
Spinal - lumbar only Epidural - anywhere
Spinal vs Epidural duration of block
Spinal - brief Epidural - longer
Spinal vs Epidural procedure time
Spinal - brief Epidural - longer
Spinal vs Epidural quality of block
Spinal - high Epidural - not as good
Spinal vs Epidural advantages
Spinal - increased risk of hypotension Epidural - dural puncture headache
What is the most common regional technique in peds for prodecures below diaphragm
Caudal anesthesia
What does the needle penetrate in caudal anesthesia
Sacrococcygeal ligament covering the sacral hiatus
What is the sacral hiatus formed by
Unfused S4-S5 vertebrae
What are the two main categories of regional anesthesia
Neuraxial blocks (spinal, epidural, caudal) Peripheral nerve blocks (single shot, indwelling catheters)
What are the levels a needle transverses
Skin–>subcutaneous–>supraspinous–>infrasponous–>flavum–>epidural space–>dura mater–>arachnoid–>subarachnoid (intrathecal)–>pia–>cord
What 2 things does the spread of a spinal depend on
1) Baricity 2) dose
What are the risk factors of PDPH
Young women, heavier, pregnant
What is the conservative treatment for PDPH
Lay down, caffiene to build CSF
Where must an epidural be placed
Approximate middle of desired dermatomal block
What determines spread of epidural
1) Volume
Which one can be used for anethesia or analgesia
Epidural
What position of receiving a block is important for post op
Lateral decubitis
Where is the most prominent cervical process
C7
Which part of the action potential does neuraxial anesthesia block
The activations of Na+ channels
Which one can achieve differential block
Epidural
Interrupting what transmission provides a sympathetic blockade
Efferent autonomic
What effects come from a sympathetic bloack
Decreased sympathetic tone or unopposed parasympathetic tone
Why is there urinary retention
Blockade of lumbar and sacral leads to blocking of sympathetic and parasympathetic
What receptors do neuraxial opioids act on
NTs that act on mu receptors on the spinal cord to transmit pain Dont cause hypotension or motor block
Why do opioids cause urinary retention
Inhibit micturation reflux, inhibit detrussor muscles
Why do opioids cause itching
Histamine, mu receptors
Why do opioids cause PONV
Chemoreceptor triggers
Which opioids cause early respiratory depression
Lipophilic like fentanyl or meperidine, absorb into epidural space
Which opioids cause late respiratory depression
Hydrophilic like morphine, caused by cephalad spread after 12 hours
Why is increased fibrinolytic activity and decreased stasis a benefit of blocks
Less risk of PVT, PE
What immune benefits come with blocks
Less infection, less tumor regrowth, less stress response
What are the cardiovascular benefits for thoracic epidural analgesia
Less MI, less dysrhythmias
How much do hematoma occur
1/100,000
How often to meningitis/abcesses occur
1/65,000-500,000
How often does dural puncture/PDPH occur
1%
What are the first signs of local toxicitiy
Circumoral numbness, metallic taste, ringing of ears, dizziness
What are the later, worse effects of local toxicity
Respiratory arrest, CV arrest (spinal)
What is Transient Neurologic Syndrome
Radicular irritation
What increases the concern for TNS
Lidocaine spinals, lithotomy
What is Cauda Equina syndrome
Direct neurotoxicity or cord trauma, reason microcatheters are banned
Which is better for postop pain
Epidural
What is flap surgery
Transfer of tissue to another site
What 2 things determine which flap is used
Size and site of defect
What are the 2 types of flaps
Pedicle, free
What is a pedicle flap
Tissue released at original site, twisted around neurovascular bundle without interruption of blood flow
What is a free flap
Tissue and neurovascular bundle removed from donor site and replaced by microsurgical anastomosis to a new site
Which flap has more reliable perfusion and better sensation
Pedicle
What would you use a latissimus doors myocutaneous pedicle flap for
Breast or chest wall reconstruction
What would you use a TRAM pedicle flap for
Breast or chest wall reconstruction
What would you use a buttock/posterior thigh pedicle flap for
Pressure sore reconstruction
What would you use a forehead or cheek interpolation pedicle flap for
Nasal deformities
Which flap has no lymph drainage initially
Free flap
What factors are free flaps still sensitive to eventhough they are desensitized to SNS
Hypoxia, hypercapnia, K+, Mg2+, osmoalility, catecholamines
Which one used a single feeder artery and vein
Free flap
What are 2 types of free flaps
Fibula flap w/ peroneal artery and vein, radial forearm flap
What are the 3 stages of free flaps
1) Primary ischemia 2) Reperfusion 3) Secondary ischemia
When does anoxic injury start during primary ischemia
Lactate, calcium, inflammatory mediators increasing - pH decreasing
What is reperfusion
Washing out of toxic metabolites
When does reperfusion injury occur
When complement and immune complex activation occurs
When does secondary ischemia occur
When massive intravascular thrombosis and interstitial edema happens
What causes secondary ischemia
Arterial/venous thrombosis, kinking/vasospasm, compression from dressings
What can cause flap edema
XS crystalloids, hemodilution, prolonged ischemia, histamines, flap manipulation
What CV factors can cause secondary ischemia
Vasoconstriction, hypovolemia, hypothermia, alkalosis, pain, hypotension, MI depressor drugs, heart failure
What does the Staged Flap/Vascular Delay involve
Vascularly undermining blood flow to flap and leaving it in place to cause angiogensis and ischemia preconditioning
What is the delay to transfer a staged flap
3 weeks
What is the main determinant of perfusion to the flap and what should you avoid
Arterial tension, vasopressors
How does isovolumetric hemodilution improve blood flow to flap
Reduce viscosity
What HCT level greatly increases viscosity
40
What is the best HCT level for desired viscosity
30
Does hypothermia increase or decrease viscosity and how
Increase by causing aggregation of RBCs
Does hyper or hypovolemia help dilate flap vessels
Hypervolemia
What should you consider monitor-wise for serial lab checks and volume status with SBP and PP variation
A line
What should you monitor if you cant get an IV
CVL, CVP
What does propofol do to platelet aggregation and why
Inhibits because its an intralipid
What patients are at higher risk for flap failure
High ASA, head/neck cancer, smokers, alcoholics, heart/lung issues, poor nutritional status
Why would airways be difficult in flap cases
Tumor or radiation
What lab should you consider running if the patient had prior chemo
ECHO
How long should smoking be discontinued for before flap surgery
3 weeks, esp TRAM flaps
A BMI of what greatly increases chance of failure
30
Patients with which 2 problems are of concern for flap surgeries
HLD, PAD
Why should you check glucose levels in diabetic patients before flap surgeries
Help reduce post op infections and vascular leakage
What blood tests should you order preop before a flap surgery
CBC, basic panel, T/C
What effects does warming your patients have on viscosity and vasoconstriction
Prevents increases in viscosity and vasoconstriction
What could you do preop do prevent thrombosis
LMW heparin, compression socks
How long do flap surgeries usually last
6-12 hours
What do you need to measure with an A line during a flap surgery
SBP/PP variation
Do you need a foley with UOP for flap surgery
Yes
What IV access do you need for flap surgeries
2 large bore IVs
What monitor should you use so you can limit anesthetic depth
BIS
What effect does hypocapnia and hypercapnia have on SVR and CO
Hypocapnia - increase SVR, decrease CO Hypercapnia - induces sympathetic stimulation
What does hyperoxia cause (CV)
Vasoconstriction, poor circulation
What drug should you NOT use during flap surgery
Pressors
What will surgeons sometimes request for improvement of flap survival
ASA, heparin
What would a surgeon inject if a vasospam occurs during flap surgery
Papaverine, verapamil, or lidocaine - but could cause hypotension
What postop monitors are used for flap monitoring
Doppler US, laser doppler, transQ O2 tension
What is the failure rate for flap surgery
4%
What does a pale and cold flap usually indicate
Arterial thrombosis
What does a congested flap usually indicate
Venous obstruction
What level should you keep UOP at for flap surgerys
Greater than 1cc/kg/hr
What should your Sat be above for flap surgeries
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