Final Exam review part III- taxonomy, MAC, Positioning, & Monitoring Flashcards
What are the components that make up anesthesia?
amnesia, analgesia, unconsciousness, immobility, and arreflexia
Describe the stages of anesthesia
Stage 3 plane 2 is where we perform general anesthesia
patients in stage 2 should not be touched because they are hyperreactive
Describe the types of anesthesia
MAC- monitored anesthesia care- sedation case where patient protects their own airway
General- inhalational or intravenous induction- patient has assisted breathing
Regional- local area block
Describe how medication syringes should be labeled.
Medication name
medication concentration
Date, time
initials
What does DAMMITTTS stand for?
Drugs Airway Machine, Mask monitors IV Temperature Tube Tape Suction
What does MSMAIDs stand for?
machine, suction, monitor, airway, IV, drugs
Reasons why your patient may fail to emerge include:
residual NMBD
excessive opioid or benzodiazepine administration
intraoperative CVA
electrolyte abnormalities
acidosis
hypothermia
Pre-existing pathophysiologic conditions such as CNS disorders, hepatic insufficiency, ETOH ingestion
A loss of lash reflex means
a loss of airway protective reflexes
What monitors are required for a MAC case?
blood pressure, end tidal, EKG, pulse oximetry, assess ventilation adequacy, presence of a qualified anesthesia provider
The medication amounts for a MAC case
are highly variable as they depend on surgeon experience, patient’s medical history, and surgical stimulus
typical medications given include versed, propofol, fentanyl or remifentanil and local anesthetic
Inappropriate cases for MAC include:
the use of muscle relaxation potentially difficult airway access pediatric patients patients with psychiatric disorders any uncooperative patient patient that refuses MAC anesthesia
What standard relates to positioning?
standard 8
What is the most common positioning injury?
ulnar nerve injury
and then brachial plexus
Goals for positioning include:
patient safety, optimize surgical exposure preserve patient dignity, maintain hemodynamic stability, maintain cardiorespiratory function, no ischemia injury or compression, prevent pressure related injuries
Mechanisms associated with nerve injury include:
compression, transection, stretch and traction
Risk factors for skin issues include
age: elderly; diabetes, PVD, surgical time, chronic hypotension, increased body temperature, body habitus
Pressure injury sites related to the supine position:
occiput, scalpulae, thoracic vertebrae, sacrum, coccyx, elbows, heels, calves
Positioning in the supine position:
arms should be secured on arm board with padding
if arms are lateral or abducted they need to be <90 degrees, supinated forearm, avoid brachial plexus injury (stretch), pronation of the forearm can lead to ulnar curve compression
legs should be flat, uncrossed with heels padded, small lumbar support
Respiratory and CV implications of supine positioning.
CV: BP stability, compensatory mechanisms (ANS) are intact
Respiratory: reduced TLC and FRC, diaphragm shifts cephalad, general anesthesia and NMBs can enhance this
Prone positioning implications
intubated
head & neck should be neutral
arms <90 degrees
body/trunk supported
What types of surgical cases use the prone position?
spine buttocks rectum or peri-rectal ankle intracranial
Areas that need to be kept free of pressure in prone positioning include:
eyes, breast, genitalia, nose, face, lower legs
What are the CV and respiratory considerations for prone positioning?
CV: pooling of blood (lower extremities/abdomen), compression of inferior vena cava, epidural engorgement
respiratory: decreased compliance if chest is not freely hanging, increased FRC (improved posterior lung ventilation may increase oxygenation
Discuss postoperative vision loss prevention:
surgical duration < 6 hours
10-15 degree head up (reduce orbital edema)
BP 20% of preoperative baseline
maintain HCT >25
Postoperative vision loss can be due to:
prolonged surgical time spine surgeries (prone) central retinal artery occlusion central retinal vein occlusion ischemic optic neuropathy (89% of POVL) cortical blindness
Ischemic optic neuropathy is associated with:
extended surgical time & extensive blood loss obesity gender--> male Wilson frame Ocular perfusion pressure It is NOT associated with globe pressure
Describe central retinal artery occulsion.
“eye stroke”
sudden profound vision loss, painless, monocular
What is the etiology of central retinal artery occlusion:
embolism, vasculitis, vasospasm, sickle cell, trauma, or glaucoma
How is central retinal artery occlusion diagnosed?
retinal pallor, macular cherry red spot, +/- afferent pupillary defect
What is central retinal vein occlusion?
“eye DVT”
variable- blurred vision to sudden vision loss, painless, monocular
What are the risk factors for central retinal vein occlusion?
typical stroke risk factors, hypercoagulable states
glaucoma, compression of the vein in thyroid or orbital tumors
How is central retinal vein occlusion diagnosed?
optic disk edema, diffuse retinal hemorrhages
Describe considerations with the lithotomy position.
legs abducted, elevated
fingers free–> footboard
legs free–> peroneal nerve injury
hip flexion- sciatic/obturator stretch, femoral nerve palsy
Lithotomy position facilitates access to:
perineal structures
gynecological
urology
Describe the CV and respiratory considerations of the lithotomy position.
20% reduced FRC, reduced VC, hypoventilation when breathing spontaneously
CV- autotransfusion of 250-300 mL/leg when raised
increased (shifted) central blood volume
Describe considerations with the lateral position.
head neutral, supported
pressure free of the eyes/ears/face
dependent arm on padded arm board, perpendicular to torso <90 degrees
axillary roll under the dependent side of thorax- should be slightly caudad, not directly in axilla
Lateral positioning is used for the following surgical procedures.
kidney, shoulder, orthopedic (THA; hip)
Thorax
What are the CV and respiratory considerations with lateral positioning?
CV: with euvolemia we have minimal changes
when the kidney rest is elevated: must do so slowly under ilia crest, great vessels compressed, decreased venous return
Resp: V/Q mismatch possible
the dependent lung lower than left atrium is prone to atelectasis and fluid accumulation
FRC: increased in nondependent lung (top), decreased in dependent lung (bottom)
The sitting position can be used for
cervical spine surgery, should surgery, posterior fossa, and breast reconstruction
Considerations with the sitting position include:
HOB 30-90 degrees above horizontal plane
Head secured with 2 finger breadths between the neck and mandible
head can be dislodge from headrest with vigorous surgical manipulation
Potential complications with the sitting position include:
venous are embolism- negative pressure gradient
pneumocephalus- neuro procedures, often benign
quadriplegia- spinal cord stretch when head flexed + loss of autoregulation with general anesthesia; limit strain at C5 vertebra level
CV & respiratory considerations with the sitting position
CV: reduced SV & CO, decreased MAP & CVP, lower extremity venous pooling, decreased cerebral perfusion
resp: increased FRC, increased compliance
Trendelenburg positioning leads to
increased ICP, IOP, CV
dependent edema
Brachial plexus stretch or compression
Reverse Trendelenburg positioning leads to
increased pulmonary compliance & FRC
decreased ICP, IOP, CPP, & BP
Injuries to the brachial plexus in supine and lateral decubitus positioning:
supine: arms abducted >90 degrees
humeral head rotated
lateral decubitus: stretch/traction/tension, chest- dependent compression
For all anesthetics ________ needs to be documented at least every 5 minutes.
Blood pressure, heart rate, and respiration
oxygenation must be continuously monitored
Pulse oximetry requires
a pulsatile arterial bed
works via Lambert-Beer law
HbO2 absorbs more infrared at 960 nm
reduced Hb absorbs more red at 660 nm
Factors that affect the accuracy of pulse oximetry include:
high intensity light, patient movement, electrocautery, peripheral vasoconstriction, hypothermia, cardiopulmonary bypass, presence of other hemoglobin (carboxyhemoglobin leads to false increased reading) methemoglobin can be positive or negative
IV injected dyes such as methylene blue or hemoglobin <5
Discuss the estimates of the oxyhemoglobin curve.
PaO2:30, SaO2: 60
PaO2: 40, SaO2: 75
PaO2: 60, SaO2: 90
The precordial stethoscope is placed at
suprasternal notch or the apex of the left lung
The precordial stethoscope
easily detects changes in breath sounds or heart sounds including airway/circuit disconnect, endobronchial intubation, anesthetic depth/increased heart rate, contractility
An abnormal PACo2-PaCO2 gradient can be due to
gas sampling errors, prolonged expiratory phase, V/Q mismatch, airway obstruction, embolic states, COPD, hypoperfusion
Describe the phases of a capnograph.
Phase 1- corresponds to inspiration (should be zero unless rebreathing is present)
Phase II- early exhalation/steep upstroke (mixing of deadspace with alveolar gas)- prolonged upstroke can be due to COPD, bronchospasm
Phase III- mild upslope; end of 3 is where we read CO2
Phase IV- inspiration & return to baseline
What lead measures arrhythmias and what lead measures ischemia?
lead II- arrhythmias Lead V (any of the V leads)- ischemia
Describe where you place the lead that reads lead II
lead II is placed on the right side, 2nd intercostal space, mid-clavicular line
An anterior MI is detected via
V3 & V4
A septal MI is detected via
V1 & V2
An inferior MI is detected via
II, III, and aVF
A lateral MI is detected via leads
aVL, V5, and V6
For patients with atherosclerosis and HTN, the BP cuff will read:
systolic low
diastolic high
as compared with invasive arterial pressure
Concerns with using the femoral artery for arterial line site selection:
pseudoaneurysm & atheroma formation
Concerns with using the axillary artery for arterial line insertion:
potential for plexus/nerve damage from hematoma or traumatic cannulation
The most common form of heat loss in the OR is:
radiation>convection>conduction>evaporation
Patients at risk for hypothermia include:
extremes of age, patients with spinal cord injuries, burn patients
The temperature sites that most reflect core temperature include
Blood (via PA catheter)
Tympanic membrane (risk of perforation
esophagus and bladder are also good at detecting core temperature
The greatest effect on maintaining body heat is
ambient temperature
When monitoring the ulnar nerve with paralytics, we are looking at
the adductor pollicis muscle
it will adduct the thumb
best for recovery
When using neuromuscular monitoring on the face, we are looking to monitor
the facial nerve
looking at the obicularis oculi muscle which closes the eyelid
Best for onset
Most reliable clinical signs of recovery from neuromuscular block include
sustained headlift x 5 seconds
sustained leg lift x 5 seconds
sustained handgrip x 5 seconds
Max inspiratory pressure >40-50 cm H2O
Unreliable signs of recovery from neuromuscular block include
sustained eye opening tongue protrusion arm lift to opposite shoulder normal TV normal or near normal vital capacity max inspiratory pressure <40-5o cmH2O
The BIS score for general anesthesia is
40-60
>70 is associated with greater recall risk
Describe your blood pressure if the cuff is too small or too large.
Too large it will have a low reading
too small it will have a high reading
