Positioning Flashcards
What AANA standard addresses positioning?
Standard 8
What are the most common nerve positioning injuries?
ulnar nerve and 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 injuries
Cardiovascular concerns related to positioning include:
redistribution of circulating blood volume
depressed cardiac output
reduced preload and SV- blood pooling (dependent)
compression of extremities or great vessels
impaired autonomic nervous system function
anatomy cephalad to heart risk hypoperfusion/ischemia
Volatile agents cause (CV effects)
decreased CO & BP
NMBs cause (CV effects)
decreased muscle return/venous return
Opioids cause (CV effects)
decreased HR (CO/BP)
To avoid dramatic effects on the CV system, it is important to
avoid quick positioning changes
Barriers to thoracic excursion include
supine, lateral and prone positioning= cephalad displacement
Prone= reduced capacity for chest expansion
Gravity related effects include
ventilation- nondependent (dead space)
perfusion- dependent (shunt)
loss of hypoxic pulmonary vasoconstriction
Mechanisms associated with nerve injury include
compression, transection, stretch, traction
Nerve sheath ischemia can be
direct or
indirect
Compression of a nerve occurs when
we force a nerve against a bony prominence or other hard surface
Transection occurs when
the nerve is cut
Stretch injury occurs when
the nerve is extended or pulled tightly
Traction injury occurs when
is pulled over or under some immovable structure which is a bone
Patients are more likely to experience a nerve injury if
they have extremes of body habitus (obese or thin)
Comorbidities associated with nerve injuries include
smoking, alcoholism, diabetes
Risk factors for skin issues include
elderly, diabetes, PVD, surgical time, chronic hypotension, increased body temperature, body habitus
smokers are prone to developing vasoconstriction of cutaneous vessels
The goal for integumentary issues is
prevent development of pressure ulcers, assess and reassess patients for pressure-ulcer risk, address identified risks.
The preoperative anesthesia interview allows us to
identify patients at risk for positioning injuries
perioperative nerve injury and comorbidities
mobility concerns?
take precautionary measures
Surgical positions include
supine, prone, lithotomy, high lithotomy, low lithotomy, jack knife, lateral, sitting (beach chair), trendelenburg, and reverse T-burg
Arm positioning for supine includes:
arms secured
armboards, padding, arm straps
arms laterally or abducted- <90 degrees, supinated forearm, avoid brachial plexus injury (stretch), pronation of the arms causes ulnar nerve compression at the cubital tunnel at elbow
tucking arms- elbow padded (ulnar nerve)
palmar aspects hands parallel to thighs/trunk
Lower limb positioning for supine includes:
legs flat, uncrossed
heel padding
small lumbar support
Cardiovascular considerations when supine
BP stability compensatory mechanisms (worse compensatory mechanisms in anesthesia
Respiratory considerations when supine include
reduced TLC & FRC
diaphragm shifted cephalad
general anesthesia and NMBs enhanced
Prone is also known as
ventral decubitus
Considerations for prone patients include
often intubated, induction/intubation on the stretcher, head/neck neutral, on anesthesia provider’s count, arms <90 degrees, elbow/axilla support, body/trunk support
What type of cases use the prone positioning?
spine, buttocks, rectum or peri-rectal, ankle, intracranial
Cardiovascular concerns for patients who are prone include
potential for compression of inferior vena cava, epidural engorgement, and pooling of blood (lower extremities/abdomen)
Respiratory concerns for prone patients include
decreased compliance if chest not hanging freely increased FRC (improved posterior lung ventilation may increase oxygenation)
When patients are prone we take special care with the
genitalia (penis), breasts, lower legs, face, eyes, & nose
Prevention of postoperative vision loss includes
surgical duration < 6 hours, 10-15 degree head up (reduce orbital edema), maintain Hct >25, & BP 20% of preoperative baseline (MAP >70 mmHg)
Postoperative vision loss can occur due to
prolonged surgical time spine surgeries (prone), cortical blindness, central retinal artery occlusion, central retinal vein occlusion, ischemic optic neuropathy (89% of the time)
Ischemic optic neuropathy is associated with
extended surgical time & extensive blood loss, obesity, male gender, Wilson frame, & decreased ocular perfusion pressure
not associated with globe pressure
It is our goal to ensure (to prevent positioning injuires)
adequate circulation, head and neck support, airway protection, anatomical alignment, and access
The goal to preventing positioning injuries is to avoid
excessive pressure (peripheral nerves, bony prominences), extremity injury, strain/dislocation of joints and muscles, eye pressure, abrasions, irritants
When moving a patient, at a minimum the
pulse oximeter should be left on
____is responsible for calling turns/repositioning
the CRNA
The primary causes of injury include
positioning negligence & lack of vigilance
Brachial plexus injury can occur from
supine: arms abducted >90 degrees, humeral head rotated
lateral decubitus: stretch/traction/tension, chest- dependent compression
Pulmonary changes with reverse trendelenburg include
increased pulmonary compliance & FRC
Reverse trendelenburg is when
the bed is flat & the head is up
Reverse trendelenburg causes a decrease in
ICP, IOP, BP, and CPP
Trendelenburg positioning is when
the head is down
Trendelenburg causes an increase in
ICP, IOP, and CVP
The degree of Trendelenburg has an effect on
dependent edema & physiologic/hemodynamic impact
For every 1 cm head rise, there is a
0.75 mmHg drop in MAP
The sitting positioning (respiratory impacts)
causes increased FRC & increased compliance
The sitting positioning causes (CV impacts)
reduced SV & CO (up to 20%), decreased MAP & CVP, lower extremity venous pooling, & decreased cerebral perfusion (CPP= MAP-ICP)
Potential complications with the sitting position include
quadriplegia, pneumocephalus, & venous air embolism
Quadriplegia due to the sitting position is caused by
spinal cord stretch when head is flexed+ loss of regulation with general anesthesia
ensure 2 fingerbreadths= limit strain at C5 vertebra
Pneumocephalus results from the sitting position because of
neuro procedures, often benign
air enters open dura, CSF drainage, surgical decompression
What is the gold standard to treat a venous air embolism?
the Durant position which is trendelenburg with left lateral decubitus and that allows the air embolism to rise to the top of the right atrium and then a central line should be inserted and the air should be aspirated
Sitting is used for
cervical spine surgery, shoulder surgery, posterior fossa, breast reconstruction
The sitting position is when
HOB 30-90 degrees above horizontal plane
OR table flexed and backrest elevated
head secured (2 fingerbreadths between neck and mandible)
arms secured (padded arm boards or patient’s lap with drawsheet)
Endobronchial intubation
pad legs, heels flexed (prevent sciatic stretch)
dislodge head from headrest with vigorous surgical manipulation
A cranial retinal artery occlusion can be caused by
embolism, vasculitis, vasospasm, sickle cell, trauma, glaucoma
A cranial retinal artery occlusion clinical signs include
sudden profound vision loss, painless, monocular
Diagnosis of a cranial retinal artery occlusion includes
retinal pallor, macular cherry red spot, +/- afferent pupillary defect
Treatment for cranial retinal artery occlusion includes
consult ophto+ neurology, possible digital massage or lower intraocular pressure
Risk factors for cranial retinal vein occlusion includes
typical stroke risk factors, hypercoagulable states, glaucoma, compression of the vein in the thyroid or orbital tumors
Clinical symptoms of cranial retinal vein occlusion includes
blurred vision to sudden vision loss, painless, monocular
Diagnosis of cranial retinal vein occlusion includes
optic disk edema & diffuse retinal hemorrhages
Treatment for cranial retinal vein occlusion includes
consult ophtho+ neurology
The lithotomy position is where
the legs are abducted, elevated
fingers free–> footboard
legs free–> peroneal nerve
Hip flexion for preventing sciatic/obturator stretch & femoral nerve palsy
The lithotomy position facilitates access to
perineal structures, gynecological, & urology
Respiratory considerations with the lithotomy position include
20% reduced FRC, reduced VC, & hypoventilation when breathing spontaneously
Cardiovascular considerations with the lithotomy position include
Increased (shifted) central blood volume
autotransfusion 250-300 mL/leg when raised
The lateral position includes
head neutral, supported
pressure free of the eyes/ears/face
shoulders, hips, head, & legs aligned
chest and hip supports or bean bag
regularly assess perfusion
dependent arm on padded arm board, perpendicular to torso <90 degrees
axillary roll under dependent side of thorax
The lateral position is used for
kidney, shoulder, thorax, and orthopedic surgeries (THA, hip)
The CV considerations with the lateral position include
Euvolemic minimal changes
w/ kidney rest elevated: slowly under iliac crest, great vessels compressed, decreased venous return
The respiratory considerations with the lateral position include
V/Q mismatch is possible, FRC is increased in the nondependent lung (top) & decreased in the dependent lung (bottom), the dependent lung lower than the left atrium is prone to atelectasis and fluid accumulation
