Perioperative Positioning Flashcards
1
Q
AANA Standards for Nurse Anesthesia Practice:
Standard 8
A
Patient positioning collaborate with the surgical or procedure team to position, assess, and monitor proper body alignment. Use protective measures to maintain perfusion and protect pressure points and nerve plexus.
2
Q
What are the two most commonly injured nervous strucutres?
A
- Ulnar nerve
- Brachial plexus
3
Q
What are 7 goals for positioning?
A
- patient safety
- optimize surgical exposure
- preserve patient dignity
- maintain hemodynamic stability
- maintain cardiorespiratory function
- no ischemia, injury or compression
- 2015 Joint Comission Patient Safety Goal #14 “prevent healthcare associated pressure ulcers”
4
Q
What are the 3 physiological systems associated with positioning injuries?
A
- Cardiopulmonary
- Nervous system
- Integumentary
5
Q
What are 3 major cardiovascular concerns related to patient positioning and implicated medications?
A
- ↓CO & BP - Volatile anesthetics
- ↓muscle tone & venous return - NMBDs
- ↓HR (CO&BP) - Opioids
6
Q
What are 3 major respiratory concerns related to patient positioning?
A
- barriers to thoracic excursion
- positive pressure ventilation
- gravity related effects
7
Q
What positions may affect thoracic excursion?
A
Prone = reduced capacity for chest expansion
Supine/Lateral/Prone = Cephalad displacement
8
Q
What are 3 gravity related effects on the pulmonary system related to positioning?
A
- Ventilation - nondependent (dead space; ventilation no perfusion)
- Perfusion - dependent (shunt; perfused, no ventilation)
- Loss of hypoxic pulmonary vasoconstriction (HPV) r/t _______
9
Q
What are the mechanisms associated to nerve injury?
A
- compression
- transection
- stretch
- traction
10
Q
Nerve sheath ischemia can be a result of _____ or ____ forces.
A
direct
indirect
11
Q
What are some risk factors for pressure injury development?
A
- Age; elderly
- diabetes
- peripheral vascular disease
- surgical time
- chronic hypotension
- increased body temperature
- body habitus
12
Q
When does patient positioning and injury prevention begin?
A
during the pre-operative interview
13
Q
4 considerations for all surgical patients & positioning:
A
- perioperative nerve injury & comorbidities
- Identify those at risk
- mobility limitations?
- always take precautionary measures
14
Q
5 “standard” (my words) surgical positions:
A
- supine
- prone
- lithotomy
- lateral
- sitting (beach chair)
15
Q
Variations in surgical positions:
A
Trendelenburg Reverse Trendelenburg High Lithotomy Low Lithotomy Jack-knife
16
Q
What are the pressure points when in supine position?
9
A
- toes
- calcaneae (heel)
- calves / thighs
- coccyx / sacrum
- thoracic vertebrae
- olecranon (elbow)
- humerous
- scapulae
- occiput
17
Q
3 Arm considerations when supine:
A
- Lateral or abducted?
- <90 degrees
- supinated forearm / palms parallel to
thighs/trunk
- avoid stretch → brachial plexus injury - arm boards, padding
- secured, arm straps
18
Q
Pronation of forearm can lead to:
A
ulnar nerve compression at the cubital tunnel (elbow)
19
Q
3 considerations/position of the legs when supine:
A
- legs flat, uncrossed
- heel padding
- consider small lumbar support
20
Q
When arms are tucked, ensure you add ___
A
padding elbow (ulnar nerve)
21
Q
How might monitoring/equipment effect positioning?
A
ensure patient is not in contact with tubing/lines/wires
22
Q
How does flexion & extension of neck effect ETT position?
A
Flexion → ETT tip down up to 1.9cm
Extension → ETT tip up, up to 1.9cm
23
Q
How does head turning effect ETT position?
A
can raise ETT tip up to 0.7cm
24
Q
What are 2 cardiovascular implications of supine positioning?
A
- BP instability
2. Compensatory mechanisms (ANS) ______
25
What are 3 respiratory implications of supine positioning?
1. Reduced TLC & FRC
2. Diaphragm shifts cephalad
3. general anesthesia & NMBDs enhance effects
26
What are some special considerations of ventral decubitus positioning?
1. patient often ventilated
2. induction & intubation occurs on stretcher, before moving to OR table
3. maintain neutral head/neck
4. movement from stretcher to OR table will be on ANESTHESIA's count
27
What are 4 special considerations of ventral decubitus positioning?
1. patient often ventilated
2. induction & intubation occurs on stretcher, before moving to OR table
3. maintain neutral head/neck
4. movement from stretcher to OR table will be on ANESTHESIA's count
28
What kinds of surgical positions use the prone position?
1. supine
2. buttocks
3. rectum or peri-rectal
4. ankle
5. intracranial
29
What 5 kinds of surgical positions use the prone position?
1. supine
2. buttocks
3. rectum or peri-rectal
4. ankle
5. intracranial
30
What are respiratory considerations for potential complications when in prone position?
1. decreased compliance if chest not freely hanging
| 2. increased FRC (improved posterior lung ventilation may increase oxygenation)
31
During prone positioning, take special care with which anatomical parts?
1. eyes
2. face
3. nose
4. breasts
5. genitalia (penis)
6. lower legs
32
During prone positioning, take special care with which anatomical parts (6)?
1. eyes
2. face
3. nose
4. breasts
5. genitalia (penis)
6. lower legs
33
Postoperative vision loss (POVL) is caused by: (3)
1. central retinal artery occlusion (CRAO)
2. central retinal vein occlusion (CRVO)
3. ischemic optic neuropathy (ION - 89% of POVL)
34
POVL is associated with which type of surgery:
prolonged surgical time, supine surgeries
| patient is positioned prone
35
What are steps to prevent POVL?
| 4
1. surgical duration <6 hours
2. 10-15 degrees head up [will reduce orbital edema]
3. BP 20% of preoperative baseline????? (MAP >70mmHg)
4. maintain Hct >25%
36
Ischemic optic neuropathy (ION) is a type of POVL and associated with what two factors?
1. extended surgical time
| 2. extensive blood loss
37
Ischemic optic neuropathy (ION) is NOT associated with which factor?
- globe pressure
38
What are patient specific factors that increase risk of Ischemic optic neuropathy (ION)?
- obesity
| - male gender
39
What is the ocular perfusion pressure equation?
OPP = MAP - IOP
40
Central retinal artery occlusion (CRAO) "nickname":
eye stroke
41
Central retinal vein occlusion (CRVO) "nickname"
eye DVT
42
What is the clinical presentation of central retinal artery occlusion (CRAO)?
sudden, profound vision loss.
painless
monocular
43
What is the etiology of central retinal artery occlusion (CRAO)?
1. embolism
2. vasculitis
3. vasospasm
4. sickle cell
5. trauma
6. glaucoma
44
What are 6 possible etiologies of central retinal artery occlusion (CRAO)?
1. embolism
2. vasculitis
3. vasospasm
4. sickle cell
5. trauma
6. glaucoma
45
What are the 3 signs to diagnose central retinal artery occlusion (CRAO)?
1. Retinal pallor
2. Macular cherry red spot
3. +/- Afferent pupillary defect
46
What is the treatment of central retinal artery occlusion (CRAO)?
1. consult ophtho + neurology
Some case reports indicate intra-arterial TPA.
Limited evidence for other treatments, including digital massage & lowering IOP.
47
What is the clinical presentation of central retinal vein occlusion (CRVO)?
Variable presentation.
1. spectrum from blurred vision to sudden vision loss
2. painless
3. monocular
48
What are risk factors of central retinal vein occlusion (CRVO)?
- typical stroke risk factors
- hypercoagulable state
- glaucoma
- compression of the vein from thyroid or orbital tumors
49
What are 2 indicators to diagnose central retinal vein occlusion (CRVO)?
1. optic disk edema
| 2. diffuse retinal hemorrhages (blood-and-thunder)
50
What is the treatment of central retinal vein occlusion (CRVO)?
1. consult ophtho & neurology
51
Lithotomy leg & finger positioning:
- legs abducted & elevated
- hip flexion
- fingers free and over end of bed (by hips)
52
Nerves at risk of damage due to hip flexion in lithotomy & mechanism of injury: (2)
1. Sciatic / Obturator (stretched with external rotation of leg or hyperflexion of the hip & knee extension)
2. Femoral nerve (palsy)
53
Lithotomy position facilitates access to:
- perineal structures
- gynecological
- urology
54
What are cardiovascular effects of the lithotomy position?
1. 20% reduced FRC
2. Reduced VC
3. Hypoventilation when breathing spontaneously
55
What are respiratory effects of the lithotomy position?
1. increased (shifted) central blood volume
56
How much volume of blood is shifted in the lithotomy position?
~200-300mL per leg when raised
57
What are possible variations of the lithotomy position? (4) - outside source
1. low lithotomy
- posterior thighs & bed make 40-60 degree angle; lower legs are parallel to bed
2. high lithotomy
- posterior thighs & bed make 110-120 degree angle; lower legs are flexed
3. hemi-lithotomy
- patient's NON-operative leg is positioned in standard lithotomy; operative leg may be placed in traction
4. exaggerated lithotomy
- posterior thighs & bed make 130-150 degree angle; lower legs are almost vertical
58
What nerves are at risk of damage in lithotomy due to knee flexion?
peroneal nerve: pressure of head of fibula by bar or support structure
saphenous nerve: pressure on medial condyle of tibia
59
Lateral position head & face considerations:
1. head neutral & supported
| 2. eyes/ears/face pressure free
60
In the lateral position ____ should be aligned.
shoulders, hips, head, legs
61
In the lateral position supporters or bean bags should be used in two locations:
hip & chest
62
In the lateral position, how should the dependent arm be positioned?
1. nearly perpendicular to torso, <90 degrees
| 2. on padded arm board
63
Where should an axillary roll be placed when a patient is in the lateral position?
under the dependent side of the thorax, slightly caudad, not directly in axilla
64
During which surgical procedures is the lateral position used?
- kidney
- shoulder
- orthopedic (THA; hip)
- thorax
65
What are respiratory considerations of the lateral position?
1. V/Q mismatch is possible
2. FRC:
- increased in non-dependent lung
- decreased in dependent lung
3. dependent lung will be lower than the left atrium → prone to atelectasis & fluid accumulation
66
The sitting surgical position is used for which procedures?
- cervical spine surgery
- shoulder surgery
- posterior fossa
- breast reconstruction
67
How is the head positioned in the sitting position?
1. HOB 30-90 degrees above horizontal plane
[OR table flexed & backrest elevated]
2. head secured (2 fingerbreadths b/t neck and mandible?)
68
Consideration of vigorous surgical manipulation when patient is in the sitting position:
dislodgement of the head from the headrest
69
How are the lower extremities positioned when patient is in the sitting position?
```
legs flexed (prevent sciatic stretch)
pad heels
```
70
How are the upper extremities positioned when patient is in the sitting position?
padded with arm boards or in patient's lap with drawsheet
71
What are three major complications associated with the surgical sitting position?
1. Venous air embolus (VAE)
2. Pneumocephalus
3. Quadriplegia
72
What are 3 major complications associated with the surgical sitting position?
1. Venous air embolus (VAE)
2. Pneumocephalus
3. Quadriplegia
73
How does pneumocephalus occur in the sitting position?
air enters the open dura
CSF drainage
surgical decompression
*often benign
74
What is the etiology of quadriplegia r/t surgical sitting position?
- Spinal cord stretch when the head is flexed & loss of autoregulation with GA
* ensure 2 fingerbreadths between the neck and mandible → will limit the strain placed on C5 vertebra
75
What are cardiovascular considerations of the sitting position?
1. reduced SV and CO
2. decreased MAP and CVP
3. venous pooling in the lower extremities
4. decreased cerebral perfusion (CPP = MAP-ICP)
76
What is the conversion factor of rise above heart & change in MAP?
1cm rise above heart = 0.75mmHg drop in MAP
77
A rise of 20cm above the heart will lead to a decrease of ____ in MAP?
15mmHg
| ie. MAP @ heart 65 = MAP @ brain 50mmHg
78
What are respiratory considerations of the sitting position?
1. increased FRC
| 2. increased compliance
79
Basics of trendelenburg position:
Head down;
severity of considerations depends on the degree of trendelenburg
80
In trendelenburg positioning, what three measurements increase?
ICP
IOP
CVP
81
What injuries can occur due to shoulder braces when in the trendelenburg position?
1. plexus stretch
| 2. plexus compression
82
Basics of reverse trendelenburg:
bed flat; head up
83
Reverse trendelenburg leads to an increase in ____ & ____.
pulmonary compliance
| FRC
84
Reverse trendelenburg will result in an increase in these 4 physiological measurements:
1. ICP
2. IOP
3. CP
4. BP
85
What is the CRNA's role in patient positioning?
1. call turns/repositioning
2. ensuring patient stability
3. Everyone's responsibility
- surgeon
- nursing
- anesthesia provider
86
Avoid excessive in 2 specific areas when positioning a patient:
1. peripheral nerves
| 2. bony prominences
87
When positioning a patient ensure these 5 things:
1. adequate circulation
2. head & neck support
3. airway protection
4. anatomical alignment
5. access
88
Effects of lithotomy on lung compliance & ventilation
↓compliance
| ↓ventilation
89
4 types of nerve injuries
1. transection
2. compression
3. stretching
4. kinking
90
What is transection of a nerve?
Nerve cut due to surgical maneuver or trauma
91
What is a compression nerve injury?
Nerve forced against a hard surface or bony prominence
92
What are the 2 types of nerve injuries most at risk for?
Compression & stretching
93
Femoral nerve damage in high lithotomy
Femoral nerve kinked under inguinal ligament when hips are flexed during high lithotomy position
94
What is a stretching nerve injury?
excessive elongation or stretching
95
What is a kinking nerve injury?
nerve pinched between two immovable structures
96
Positioning device injury to lateral femoral cutaneous nerve is from...
tight thigh table strap or leg holding device used for knee arthroscopy
97
Positioning device injury to common peroneal nerve
candy cane stirrups
98
Positioning device injury to brachial plexus
armboard falling off OR table or shoulder braces with steep trendelenburg position
99
Shoulder braces should be positioned, where?
Outer side of the clavicle
100
positioning device injury to radial nerve
compression injury d/t tourniquets (TQ) or BP cuffs
101
improper positioning of an axillary roll may cause
compartment syndrome
102
procedures >4 hours are ↑ concern for..
```
- post-op vision loss
nerve injuries
compartment syndrome
rhabdomyolysis
acute renal failure
```
103
muscle relaxation increases risk of which positioning injury?
stretch injury d/t increased mobility of joints
104
hypotension increases the risk of which positioning injury?
low perfusion pressure → ischemia
105
Peripheral nerve blocks increase the risk of which positioning injuries?
block technique, hematoma formation → compartment syndrome & needle trauma
106
Ulnar nerve injury & gender
3:1 male/female predominence
107
what are the ulnar nerve anatomical differences between women & men?
tubercle of the coronoid process
- covered only by skin, subQ fat, very thin aponeurosis of the flexor carpi ulnaris
larger and the nerve & blood vessels passing by it are less protected by subQ fat in men than in women
108
Underweight concerns in positioning
lack of adequate adipose tissue over bony prominences
may develop decubiti or nerve damage
109
muscular physique concerns in positioning
↑ risk for compartment syndrome & ulnar nerve injury
110
obesity concerns in positioning
large tissue masses place increased pressure on dependent body parts
111
preexisting conditions that increase the risk of positioning injury
```
HTN
DM
PVD
peripheral neuropathies
alcoholism
smoking
subclinical ulnar nerve entrapment
anemia
liver disease
limited joint mobility
```
112
6 types/locations of position related injuries
1. ulnar nerve
2. brachial plexus
3. spinal cord
4. post-op visual loss
5. compartment syndrome
6. venous air embolism
113
What is the ultimate goal of patient positioning?
allow optimal surgical access while minimizing potential risk to the patient
114
What are 5 factors that affect physiological changes during surgical positioning?
1. surgical position
2. length of time
3. padding & positioning devices used
4. the type of anesthesia given
5. operative procedure
115
What 2 physiological effects do volatile anesthetics have on the cardiovascular system?
1. depression of the CNS & myocardial depression
| 2. vasodilation
116
What physiological effects do NMBs have on the cardiovascular system?
abolished normal muscle tone
117
What physiological effects do opioids have on the cardiovascular system?
slow HR
118
What physiological effects does supine position have on the cardiovascular system?
minimal changes
119
What physiological effects does sitting/prone/lateral position have on the cardiovascular system?
↓BP
| ↓CO
120
What physiological effects does lithotomy position have on the cardiovascular system?
BP will be ↑ or normal
121
In sitting position, where should the arterial line transducer be placed?
at the level of the head
122
What is a goal MAP for a patient >50y in the sitting position (cuff BP)
MAP 70 or higher
123
Robert Taylor Drinks Cold Beer
```
root
trunk
division
cord
branches
```
124
Position that can cause a stretch injury brachial plexus
arm abducted, head turned opposite side
unsupported shoulder
125
In sitting position, close to 90degrees, what is the effect on FRC
↓FRC b/c diaphragm pushes up
126
In sitting position, close to 30degrees, what is the effect on the FRC?
FRC should be increased (compared to supine)
127
what is the #1 concern with nerve injury?
ischemia
128
Hyperflexion of the neck can cause:
spinal cord injury. & ischemia
spinal cord moves anterior toward the vertebral body & is stretched
129
Maintain ___ space between sternum and chest in sitting position
2 finger breadths to prevent hyperflexion of the neck
130
5 ways to attenuate hemodynamic changes when positioning
1. slow or gradual changes in positioning
2. modify anesthesia technique to maintain stable vitals
3. gradual attainment of level of anesthesia
4. intravascular volume loading prior to positioning
5. trendelenburg
131
prone & trendelenburg position effects on intracerebral venous pressure
increased
132
lithotomy & trendelenburg position effects on blood distribution
↑myocardial work
hypo-perfusion of the lower extremities
133
Occlusion of the ophthalmic artery will prevent blood flow to where?
the entire eye
134
The supine position will decrease FRC by how much?
0.8-1L
135
Induction will decrease FRC by how much?
0.5L
136
Effects of supine position on lung compliance & ventilation
↓compliance
↓ventilation
(same as lithotomy)
137
Effects of prone position on lung compliance & ventilation
improved oxygenation
improved compliance
*** if abdomen is "hanging"
138
Effects of lateral position on dependent lung compliance & ventilation
Dependent lung:
↓compliance
↓ventilation
139
Effects of lateral position on nondependent lung compliance & ventilation
↑compliance
| ↑ventilation
140
2 tools to detect a VAE
1. ETCO2
| 2. precordial doppler
141
What will the ETCO2 do in the event of a VAE?
big, immediate drop
142
Precordial doppler
Mill-Will?? murmur?
143
Precordial stethoscope
diaphragm to stick on chest
144
Concerned about a VAE? use these 2 things:
CVP to pull air out of the right atrium
left lateral decubitus
145
3 patient factors that increase the risk of perioperative nerve injury
1. T2DM
2. tobacco use
3. HTN
146
What procedures use the supine position?
ENT, chest, head, abdomen, extremity
147
Where are the arms in supine position?
1. abducted and secured on arm boards
| 2. padded & secured next to body
148
Where are the legs in supine position?
flat, uncrossed, heel padding, support under knees
149
What is the nerve on the anterior side of the leg that is prone to injury in supine position?
sural nerve
150
What is the nerve on the posterior side of the leg that is prone to injury in the supine position?
superficial peroneal nerve
151
What/where is the cubital tunnel?
groove between the medial epicondyle of the humerus and the olecranon of the ulna
152
Claw hand occurs with what nerve injury?
ulnar nerve injury
153
Wrist drop occurs with what nerve injury?
radial nerve injury
154
Is VR increased or decreased in supine position?
increased d/t gravity
155
What happens to HR in supine position?
initially is elevated; increased CO & BP lead to ↓SNS = ↓HR & vasodilation *final result
156
3 factors that will ↓FRC
supine (cephalad displacement of the diaphragm)
general anesthesia
neuromuscular blockade
157
In lithotomy position, the legs should be flexed < ___ at the hip
90
158
In extreme flexion of the knees, obstruction of the ____ _____ & ___ can occur
popliteal vasculature & nerves
159
What nerves are at high risk with flexion of the hips/knees
Sciatic nerve > splits into the common peroneal nerve & the tibial nerve
160
Moving the legs together prevents ___ of the ____ &/or ____
stretching of the lumbosacral plexus &/or sciatic nerve
161
Moving the legs together avoids strain on the
- pelvic ligaments
162
Moving the legs together prevents ___ dislocation
hip
163
Moving the legs together avoids injury of __ nerve
femoral
164
Pressure on the lateral aspect of the leg can cause injury to which nerve?
peroneal nerve
165
Compression on the medial aspect of the leg can cause injury to which nerve?
saphenous nerve
166
A patient with PVD will have impaired tissue perfusion when?
after autotransfusion d/t lithotomy position
167
Once legs are lowered from lithotomy position, what may present itself at that time?
hypovolemia
168
What are some procedures that require the lateral position?
```
intracranial
shoulders
thoracic
kidney
hips
other orthopedic surgeries
```
169
An axillary roll is placed to decompress 3 anatomical structures
1. shoulder
2. axillary vasculature
3. brachial plexus
170
In lateral position, the dependent leg can be ___
flexed for stabilization
171
What are the three most common sites of injury when in the lateral position?
1. brachial plexus
2. ulnar nerve
3. peroneal nerve
[of the dependent side]
172
What can cause direct caval compression leading to ↓VR & hypotension?
kidney-rest
173
What can lead to post-op blindness?
- ↑IOP
| - retinal artery occlusion
174
During surgery, high intra-abdominal pressure may lead to
↓VR & ↓CO
| epidural vein engorgement
175
What might lead to increased venous blood loss during spine surgery?
engorgement off the epidural vein d/t increased intra-abdominal pressure (prone position)
176
In the sitting position, it is important to flex the knees to prevent injury to what nerve?
Sciatic nerve
177
Keeping 2 fingerbreadths between the neck and mandible will prevent strain on what?
C5
178
Shoulder braces, when used in trendelenburg can lead to damage of what?
the brachial plexus
179
If a patient's legs are NOT uncrossed during surgery, the top leg can experience damage to which nerve?
sural nerve
180
If a patient's legs are NOT uncrossed during surgery, the bottom leg can experience damage to which nerve?
superficial peroneal nerve
181
In reverse trendelenburg what positioning structure is used?
foot board
