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What are the 4 basic surgical positions?
- 1. supine
- 2. prone
- 3. lateral
- 4. lithotomy
What is compartment syndrome?
swelling of tissues within a muscular compartment which causes damage to neural and vascular structures
How do you treat compartment syndrome?
fascia is cut away to relieve pressure or tension
What are some reasons for intraoperative hypotension?
- 1. the surgeon requests for patient to be hypotensive
- 2. blood loss
- 3. decreased tolerance to anesthesia meds
What are some factors that contribute to the risk of development of compartment syndrome?
- 1. prolonged procedures
- 2. surgical positions
- 3. elevation of extremities
- 4. intraoperative hypotension
- 5. increasing age
- 6. extremes of body habitus (very high or low body weight)
If compartment syndrome is not treated what happens?
tissue necrosis which leads to myoglobinuria then acute renal failure
end result -- amputation
Which nerves are most susceptible to nerve injury during surgery??
- -superficial nerves
- -nerves with a long course (such as brachial plexus)
- -nerves in areas where they are poorly covered by overlying tissue
Nerve injury typically occurs because of what two reasons??
poor positioning and poor padding during surgery
but it can also occur when properly positioned and padded if increased risk factors
What nerve is most commonly injured nerve of the upper extremities during surgery??
ulnar and brachial plexus
What nerve is most commonly injured nerve of the lower extremities during surgery??
What is important to remember with tourniquets??
it is your responsibility to keep track of timing on tourniquets... make sure to chart when they are up and down.. notify the surgeon when the tourniquet needs to be released
What is the most common site of postoperative neuropathy??
What are two causes of ulnar neuropathy?
hyperextension of the elbow and compression on the nerve
How will you know a patient has ulnar neuropathy??
they are unable or abduct to oppose the fifth finger
they have decreased sensation in the 4th and 5th fingers
eventually they will present with atrophy of the hand muscles -- claw hand
How should you position a patients hand to prevent damage to the nerves in the hand??
How will a patient with brachial plexus injury typically present??
sensory deficit noted in ulnar distribution
Why is the brachial plexus injured during surgery?? Name 4 ways that this damage occurs...
bc it is so long and superficial, it is easily susceptible to stretching or compression due to its length
- most often occurs when:
- 1. the arm is abducted >90 degrees
- 2. there is lateral rotation of the head,
- 3. sternal retraction and
- 4. direct trauma/compression
What causes radial neuropathy??
direct pressure on nerve
Damage to the radial nerve results in?
wrist drop, inability to abduct the thumb or extend the metacarpphalangeal joints
What causes median neuropathy??
IV insertion into the AC area
this is rare
If you have damage to the median nerve how will you patient present??
the patient will be unable to oppose the first and fifth digits, patient will also have decreased sensation over the palmar surface of the lateral three and half fingers
What is the most common injury in the lithotomy position??
peroneal and sciatic neuropathy
What causes damage to the sciatic and common peroneal nerves?
stretching of sciatic nerve with external rotation of the leg, hyperflexion of the hips, extension of the knees
common peroneal nerves is often compressed between the head of the fibula and fetal frame of the stirrups
How will the patient present with injury to the sciatic or common peroneal nerves?
footdrop, inability to extend the toes in the dorsal direction, unable to evert the foot
how does femoral and obturator neuropathy occur??
during lower abd. surgeries with excessive retraction, difficult forceps delivery, or excessive flexion of the thigh to the groin
How will a patient present with damage to the femoral nerve?
will have decreased flexion of hip, decrease extension of knee, loss of sensation of superior aspect of thigh and medial/anteromedial side of leg
how will a patient present with damage to the obturator nerve?
- will have inability to adduct the leg
- will have decreased sensation over medial thigh
Nerve injuries are generally _____.
only require assurance
How long does it typically take to recover from a nerve injury??
to get full movement and sensation back
What is the position of choice that causes the least amount of harm to the patient??
Where should the safety belt be placed?
2" above the knees while not impeding circulation
should be able to place one hand under belt
Why should you not allow patients to be positioned with their feet/ankles crossed?
decreases perfusion and causes damage
The supine position is aka??
What procedure typically use the supine position??
procedures of the head, neck, extremities and chest
How should you position a patients head if they have decrease cervical mobility??
let the patient position themselves before induction
Why do patients develop back aches during procedures??
bc anesthesia blocks the normal spinal curvature and muscles...this is why you should pad the lumbar spine
The alteration of the supine position to the lounge chair is favorable because??
it helps increase comfort for patient
What are cardiovascular considerations when taking care of a patient in the supine position during surgery??
- -increase venous return (in comparison to standing)
- -increased preload->increased CO->increased BP
What are some respiratory considerations to be aware of when your patient is in the supine position during surgery??
- -decreased FRC and TLC in comparison to a standing or sitting position
- -shift of the diaphragm towards the head
- -decreased elastic recoil and decreased A-P diameter
- -flexion of the head which can cause displacement of the ETT
What should the anesthetist do before the OR staff turns a patient to the prone position??
- 1. put the patient to sleep on the stretcher
- 2. turn the gas up and turn the o2 to 100%
- 3. then move the patient over to the OR table after securing the ETT good!
Where are chest rolls placed in the prone position??
- -two are placed lengthwise under the axilla and along the sides of the chest from the clavicle to the iliac crests (to raise the weight of the body off the abdomen and thorax)
- -one roll is also placed at the iliac or pelvic level
- -should also have pillow under feet
basically support them from the clavicle to the iliac crest and all bony areas
What is important to be concerned about when a patient is placed in the prone position??
the position of the breasts and male genitalia
must be free from pressure and torsion
**you should also check the position of the dependent eye and nose if the patients head is facing to the side as well as monitoring of the ETT to ensure good position
For what kind of surgeries is a patient placed in the prone position??
procedures of the spine, posterior fossa, buttocks or rectum
How do you avoid hyperextension of the neck when a patient is in the prone position???
the shoulders should be position higher than the head
List some modifications of the prone position..
- flat back prone position
- jackknife position
- sitting prone position
The arms should never be ______. or you'll have injury to _____.
- abducted more than 90 degrees
- will damage the brachial plexus
How are the arms positioned when in the prone position?? and if you use armboards how should they be positioned??
the arms can be tucked parallel to the trunk
or they can be slightly pronated and lateral to the head
armboards should be lower than the shoulders
What are 3 cardiovascular considerations to be aware of with a patient in the prone position during surgery??
- decreased CO
- avoid pressure over the abdomen
- avoid extreme flexion of the hips
What are some respiratory considerations to be aware of with a patient in the prone position during surgery??
- -FRC will be decreased compared to sitting but less than that of the supine position
- -if the abdomen can hang freely
- -the patient will have better diaphragmatic excursion
- -there will be less pressure on the abdominal/thoracic region
- -this position allows for increased oxygenation --better ventilation-perfusion ratios
Besides respiratory and cardiovascular considerations...what are 4 other complications of the prone position??
- 1. optic nerve ischemia (due to alterations in perfusion pressure, hypotension, hypovolemia, emboli and increased IOP)
- 2. venous air embolism
- 3. brachial plexus injury
- 4. facial edema (remember---if swollen on the outside..will be swollen on the inside too...be aware of this when planning to extubate)
How does a venous air emboli occur?? how do you treat it?
occurs due to negative pressures that develop if surgical site is higher than the heart
a central venous catheter tip is place at the junction of the IVC and RA to withdraw air from VAE
The lithotomy position is typically used for what procedures??
procedures requiring access to any perineal structures (gyno, urological, colo-rectal)
What should you remember when positioning the legs for the lithotomy position???
make sure to position them at the same time...if not you could cause trauma
use two people to do this
What is hemilithotomy??
only one leg is elevated instead of the typical lithotomy position where both legs are elevated
sometimes used for orthopedic surgeries
If you tuck a patients arms when in the lithotomy position it is important to remember to pay close attention to....
their fingers...when raising the foot section of the bed... you can crush their fingers if the arms are left to the side
if you place the arms out from the side this allows easier access -- using armboards is recommended
When should you position a patient in the lithotomy position before a procedure???
once you have an airway
if you go ahead and pull the patient down it will be hard for you to intubate the patient...especially if they are a difficult airway.
Whenever a patient's position is changed, what is the CRNA's responsibility???
always recheck the tube placement, listen for breath sounds, ensure that all monitors are attached properly and are reading correctly...then once that patient is finally in a position for the procedure...secure the tube how you want it!
List a few cardiovascular considerations to be aware of for a patient in the lithotomy position...
- 1. central blood volume will be increase (blood flows down the legs to the abdomen
- 2. this position doesn't effect healthy adults
- 3. this position can be detrimental if combined with trendelenburg in a patient with cardiac issues
- 4. if the patient has PVD there is increased risk for hypoperfusion, ischemia, and compartment syndrome
- 5. if the patient is hypovolemic, they may not have symptoms until the legs are lowered back into a neutral position--may develop severe hypotension
What are some respiratory considerations to be aware of for a patient in the lithotomy position???
- 1. this position is very similar the symptoms seen in the supine position (increased venous return so increased CO and ICP)
- 2. further decrease in FRC if patient in trendelenburg as well
- 3. diaphragm displacement
What are some noncardiac and respiratory complications of the lithotomy position??
- 1. hip dislocation (occurs when legs raised individually)
- 2. hip/back pain
- 3. femoral nerve or lumbosacral plexus stretch injury
- 4. arterial or venous occlusion or nerve palsy due to kinking of nerve structures
- 5. impaired venous outflow
- 6. compartment syndrome (due to stirrups)
- 7. peroneal nerve injury
For what procedures would you use the lateral position for surgery??
procedures involving the thorax, kidneys, posterior or lateral spine, craniotomies requiring access to lateral or posterior cranium, and some orthopedic surgeries
A bean bag is often used for the lateral position...what is it??
it is put under patient and they are wrapped in it, it is hooked to suction, the air is sucked out, the bag will harden, it is then used as a holding device to keep the patient in place on the bed
Which leg is flexed in the lateral position??
the depended leg is flexed at the knee and hip..the nondependent leg stays straight.. a pillow should be placed between the legs
how are the arms positioned in the lateral position??
the dependent arm is typically supinated on a padded armboard, abducted less than 90 degrees
the nondependent arm should be parallel with the dependent arm, level with the shoulder on an arm holding device or with pillows/blankets between the two arms
Where should the chest roll be placed when a patient is in the lateral position??
- under the dependent thorax
- slightly caudad to axilla---not in the axilla
What are some cardiovascular considerations for a patient in the lateral position for surgery??
- 1. bp changes are usually minimal
- 2. hypotension is possible with severe flexion (lowering of the legs in comparison to the upper body)
What are some respiratory considerations for a patient in the lateral position for surgery??
1. mediastinum will shift toward the dependent lung, decreasing the FRC in that lung as well as compliance and ventilation
ventilation-perfusion mismatch occurs because gravity pulls blood to the dependent lung but the independent lung is receiving the oxygenation
- 2. abdominal contents will force the diaphragm towards the head
List 3 complications of the lateral position (other than resp and cardio complications).
- 1. nerve injury (brachial, ulnar and peroneal are the most common)
- 2. damage to the dependent eye
- 3. rhabdo (caused by placing positioning devices against muscle rather than bony prominences)
What surgeries is the sitting position typically used for??
procedures of the posterior fossa, cervical spine, breast reconstruction and shoulder surgeries
You want to avoid extreme flexion of the neck with the sitting position...what two things can be caused bc of excessive flexion???
- 1. endobronchial intubation
- 2. jugular venous obstruction
How can you check placement of the tube when in the sitting position??
there should be 2 fingerbreaths between the neck and mandible to prevent endobronchial intubation
What are some cardiovascular considerations for a patient in the sitting position for surgery??
- 1. there are increased risk of profound hemodynamic effects depending on the level of elevation of the torso (ex. blood will pool in the lower extremities, decreased CI, CVP, PAWP, increased SVR)
- 2. risk for threatened intracranial perfusion (hypocarbia, increased ICP, hypoperfusion due to hypotension)
Your MAP ___ by ___mmHG per 1 cm of elevation.
Where should the transducer be positioned if an art line is used during the procedure?
at the circle of willis
How does a venous air embolism occur??
due to air entering the venous system
negative pressure gradient between veins at the operative site and right atrium
What will you hear when the air emboli gets to the heart with an esophageal stethoscope??
What can you do preoperatively to rule out the patient has a patent foramen ovale??
What is the gold standard intraoperatively to check for a VAE?
do a TEE
can also use a precordial Doppler -- 3rd to 6th intercoastal spaces, right of the sternum (this is equally as sensitive as TEE in detecting, but less useful in localizing), a bovi may also pick this up.
What are some complications of the sitting position??
What is the most common cause of postoperative vision loss after surgery in the prone position??
ischemic optic neuropathy
All patients who are place prone for surgey should have a documented discussion r/t _____.
Postoperatively... anemia should be corrected to a HCT of ?
What should a patient's bp be post op?
20% above preop
THE MAJORITY OF PATIENTS WITH POSTOPERATIVE VISUAL LOSS HAVE BEEN DIAGNOISED WITH ??
ISCHEMIC OPTIC NEUROPATHY
PERFUSION TO THE OPTIC NERVE MIGHT BE LIMITED BY??
HIGH VENOUS PRESSURE OR EDEMA FORMATION
HOW DO YOU CALCULATE CEREBRAL PERFUSION PRESSURE??
MAP-CVP OR ICP (WHICHEVER IS HIGHEST)
IN THE UPRIGHT POSITION, THE EXTERNAL AUDITORY MEATUS IS THE EXTERNAL LANDMARK FOR??
CAN BE USED TO ESTIMATE THE POSITION OF THE BASE OF THE BRAIN