Positioning And Nerve Injury Flashcards
How does trendelenburg and lithotomy affect blood circ?
Blood shifts towards central > increase venous return >shifts Frank starling curve to the right
**MAP stays the same or increases
**venous pressure increases > increased hydrostatic pressure > edema of face, eye, and airway
What are some complications to Tberg and lithotomy?
Patients with poor cardiac fx may not tolerate shift
Mask hypovolemia
How does sitting, flexed lateral and prone affect blood circ?
Away from central > venous pooling > decreased venous return > shifts patient to the left on Frank starling
**higher incidence of Hemodynamic instability (decreased SV, CO, and BP)
**risk of cerebral hypoperfusion
Where should you zero the a-line in a patient in the sitting position?
Auditory meatus
How does t-berg affect the pulmonary system?
Diaphragm moves cephalad
FRC is reduced
Pulmonary compliance is decreased
Risk of endobronchial intubation is increased
How does the head up position (reverse t) affect the pulmonary system?
Diaphragm caudad
Increased pulmonary compliance
Decreased peak pressures
Increased total lung volume
Increased FRC
What should you do if you are concerned about airway patency before extubation?
Perform a leak test
Visually inspect the larynx
How should you position for a robotic assisted laparoscopic radical prostatectomy?
Arms ticked at side on a non-sliding mattress
When is the risk for brachial plexus injury the highest?
When the arms are abducted > 90 degrees and the head is rotated to the other side
Should you ever use shoulder braces?
No! They do more harm than good. A non-sliding mattress is the better option
How do you assess for thoracic outlet syndrome? Especially in prone
Ask patient to clasp hands behind their head ~ if pain, tuck arms in prone position
Where is a axillary roll placed?
Distal to the Axilla
How are the legs positioned in laterus decubitus?
Downside though and knee are flexed; upside thigh and leg are extended and separated by pillow
What is the most commonly injured peripheral nerve?
Ulnar nerve
Presentation:
> impaired sensation to 4th or 5th digit
> inability to ABDuct or oppose pinky finger
> chronic injury presents as CLAW hand
What is claw hand?
Chronic ulnar nerve injury
Wha rare some risk factors to ulnar nerve injury?
Male gender
Preexisting ulnar nerve injury
Extremes of body habitus
Prolonged hospital stay
Cardiac surgery
What is the Best way to position the arm in the supine patient?
Abducted < 90 with hand kind of in the middle (not supinated, not pronated)
Are sensory deficits or motor deficits more serious?
Motor
If sensory, ~ tend to resolve on their own. If > 5 days, consult neurology
If motor ~ more serious, can take up to 6 wks to heal ~ will need a neuro cosult
Which nerve can be injured as result of traumatic IV insertion?
Median nerve
What vascular objects is the median nerve next to?
Basilic vein and median cubical veins
What is the only nerve that passes the carpal tunnel?
Median
What other conditions can affect the median nerve?
Carpal tunnel syndrome
Elbow hyper extension
Forced elbow extension during positioning after NMB
How does a median nerve injury present?
Reduced sensation over palmar surface of thumb, index finger, middle finger, and lateral aspect of ring finger
> unable to oppose thumb
hand of benediction (make a clenched fist)
ape hand deformity
What nerve is injured in ape hand deformity?
Chronic median nerve injury
What are the 4 most common ways the radial nerve can be injured?
External compression by an IV pole
Excessive cycling of the BP cuff
Upper extremity tourniquet
Sheets that are too tight
what is the main presentation with radial nerve injury?
Wrist drop
**inability to extend the hand at the wrist
Where does the long thoracic nerve arise from?
C5-C7
What does the long thoracic nerve innervate?
Serratus anterior muscle
(SALT ~ serratus anterior long thoracic)
What are some causes of long thoracic nerve injury?
Lateral position
Trauma
Preexisting neuropathy
How does a long thoracic nerve injury present?
Scapular winging
How does a suprascapular nerve injury present?
Dull shoulder pain
Causes: patient in lateral decubitus rolls onto dependent arm
Which nerve is highly susceptible to injury when placed in stirrups?
Common peroneal
What is the presentation of a common peroneal nerve injury?
Foot drop
Inability to every the foot
Inability to extend the toes dorsally
How does a obturator injury present?
Inability to addict the leg; reduced sensation over medial aspect of thigh
**causes: excessive flexion of thigh, excessive traction during lower abd surgery, forceps delivery
How does a femoral nerve present?
Impaired knee extension/hip flexion
Reduced sensation over anterior thigh
**causes: excessive traction during lower abd surgery
How does a saphenous injury present?
Reduced sensation over anteriolateral aspect of leg
**causes medial aspect of leg leans against the supporting cradle in the lithotomy position
How does a sciatic injury present?
Foot drop
**causes: extreme hip flexion or external rotation of the legs, sitting with straight legs
What does a pudendal injury present?
Loss of peroneal sensation
**causes: compressed against peroneal post on an orthopedic fx table
What two nerves can be injured if patients legs are crossed during case?
Sural injury (top leg)
Superficial peroneal injury (bottom leg)
Which complications are MOST commonly associated with the sitting position?
Mid cervical tetraplegia
Paradoxical air embolism
When is compartment syndrome most commonly seen?
Lithotomy
Risk factors:
> surgical time > 2-3 hours
> increased BMI
> decreased tissue oxygenation (hypotension)
What is the treatment for compartment syndrome?
Fasciotomy
What is associated with hyper flexion of the neck (chin to chest)?
Midxcervical tetraplegia
Ischemia can occur as result of stretching and compression of the mid cervical spinal cord (C5)
Which table is better ~ Jackson or Wilson?
Jackson!!
What are the 4 tumors likely to occur in the anterior mediastinum?
Thymoma
Teratoma
Thyroid
“Terrible” lymphoma
What 3 vital structures can a tumor in the anterior mediastinum compress?
Tracheobronchial tree
Pulmonary tree
Superior vena cava
**these patients may present with super vena cava syndrome (edema of the neck, face, and upper torso)
What 3 things worsen tracheobronchial compression?
General anesthesia
Supine position
PPV
What can you do if the airway collapses prior to airway securement in an anterior mediastinum mass?
Position patient laterally or in prone position
***a rigid bronch should be available
