Positioning Flashcards
1
Q
“Res ispa loquitur”
A
“the thing speaks for itself”
2
Q
A
identify major safety concerns
patterns of injury and strategies for prevention
improve patient safety by anesthesiologists working in pain management, operating rooms, labor floor, remote locations and critical care.
3
Q
After induction, the patient can no longer respond to
A
painful stimuli with poor positioning
4
Q
“most commonly associated” with positioning-related problems in anesthetized or sedated patients
A
Tissue stretch and compression
5
Q
Stretch
A
> 5% of normal resting length
Kinks or decreases lumens feeding arterioles and draining venules
-Direct Ischemia: reduced arteriole blood flow
-Indirect ischemia: venous congestion
6
Q
Compression
A
(neuropraxia or axonotmesis)
Direct pressure reduces local blood flow & cellular integrity
tissue edema, ischemia and possibly necrosis
Padding
7
Q
T/F
We don’t really know “exactly” why nerve injuries happen
A
True
8
Q
Mechanisms of Positioning Injury
A
Periop Inflammatory Response
-Inflammatory neuropathy
-Microvascular neuropathies
-Autoimmune disease/Viruses/immunosuppression
Radiation-induced
Systemic inflammation from drugs, transfusions of blood products
9
Q
Perioperative Inflammatory Responses
A
-Inflammatory neuropathy
-Microvascular neuropathies
-Autoimmune Dz/Viruses/immunosuppression
10
Q
Goals of Proper Positioning
A
Clear view & best access to surg site
Anesthesia can give drugs
reduce bleeding & resp issues
less risk pressure/nerve injury & circulation
11
Q
Team Member Responsibilities
Surgeon
A
Optimal procedural exposure
12
Q
Team Member Responsibilities
Anesthesia
A
-Physiologic requirements (ABC’s)
-Ongoing assessment
-Ensure patient safety
13
Q
Team Member Responsibilities
Nursing
A
-Safe transfer
-padding and positioning aids
-Ongoing assessment
14
Q
T/F
Positioning is everyone’s responsibility.
A
True
15
Q
biggest physiologic consequence of position changes
A
HypoTN
16
Q
you must recheck and document breath sounds when…
A
head, neck or whole body moves
(ETT migration possible)
17
Q
You MUST document every position change, along with…
A
how you protected the patient
18
Q
Common Perioperative Neuropathies
A
Ulnar Neuropathies
Brachial Plexopathies
Median Neuropathies
Radial Neuropathies
Lower Extremity Neuropathies
19
Q
Most COMMON perioperative neuropathy
A
Ulnar Neuropathy
20
Q
Key factors associated with ulnar neuropathy:
A
-Direct extrinsic nerve compression (often medial aspect of elbow)
-Intrinsic nerve compression (associated with prolonged elbow flexion)
-Inflammation
21
Q
Risk factors for Ulnar Neuropathy
A
Mainly:
Male, high BMI, older, prolonged postop bed rest
Others:
Abnormal ulnar nerves before surgery (Contralateral neuropathy)
Poorly formed fibrotendinous roof of the cubital tunnel
External compression in the absence of stretch
22
Q
only major peripheral nerve in the body that always passes on the extensor side of a joint
A
ulnar nerve
All other major peripheral nerves primarily pass on the flexion side
23
Q
Flexion vs extension
A
We prefer extension
24
Q
What happens when peripheral nerves stretched >5% of their resting length
A
start to lose function and can develop ischemia
25
> __° degree of elbow flexion stretches the ulnar nerve
(≅___° high-risk for injury)
90
110
26
Anatomy and Elbow flexion
Ulnar nerve passes:
behind medial epicondyle
under the aponeurosis that holds the two muscle bodies of the flexor carpi ulnaris together
27
Anatomy and Elbow flexion
.... is thick, especially in men
Proximal edge of aponeurosis (**cubital tunnel retinaculum**)
28
Ulnar nerve injury
Compression at nerve between ...
table and medial epicondyle
29
Ulnar nerve injury
prevention
supination
avoid hypotension and hypoperfusion
Pad arms properly
30
Ulnar nerve injury
Manifested by
inability to abduct the 5th finger
Weakness / atrophy of hand muscles “claw-hand”
Numbness/tingling/pain in lateral hand on affected side
31
Outcomes
Sensory Only Neuropathy
40% resolve within 5 days
80% resolve within 6 months
32
Outcomes
Sensory & Motor Ulnar Neuropathy
20% resolve within 6 months
Many have permanent pain and dysfuction
33
Follow Up
Sensory - only neuropathy
Observe patient as most resolve within 5 days
persists = neurologist consult
34
Follow Up
both motor and sensory neuropathy
Consult neurologist ASAP
may need decompression surgery
35
Brachial Plexus Injury
Most common in...
patients undergoing **sternotomy** (especially those with **internal mammary artery mobilization**)
Things to think about:
Brachial plexus entrapment
**Prone** positioning
Anatomy of shoulder **abduction**
36
Many patients don’t notice or complain until up to 48 hours later.. why?
We've medicated them heavily
37
Brachial Plexus Injury
Patients in ___ have a higher risk than supine
prone and lateral
38
Brachial Plexus Entrapment
Prone and lateral position patients:
entrapped between compressed clavicles and rib cage
39
Prone positioning
(surrender position)
somatosensory-evoked potential changes when their arms are abducted
40
T/F
Shoulder Braces can cause brachial plexus injury
True
braces tight against the base of the neck
should be more laterally over the acromioclavicular joint
41
Proper Shoulder Brace placement
more laterally over the acromioclavicular joint
42
Causes of Brachial Plexus Injury
These stretch the plexus
43
What injury should be concerned with after a procedure using a sternal retractor?
Brachial plexus
44
shoulder abduction goal
avoid abduction > 90°
45
shoulder abduction > 90°
places the distal plexus on the extensor side of the joint and possibility of stretching the plexus
46
Brachial plexus injury
How it happens
Excessive external rotation or abduction of arm
Avoid:
> 90 degree abduction
arm falling off of table
47
Brachial plexus injury
Positions affecting it
prone:
watch flexion & abduction of arms overhead
Lateral position:
-requires a **chest roll (inaccurately called an axillary roll)**
-avoids compression of humerus into axilla
-avoids compression of neurovascular bundle in axilla
48
When a pt is in lateral position, use which method to avoid brachial plexus injury?
Chest roll
(inaccurately called an axillary roll)
49
Brachial Plexus Nerve Injury
Manifestations
depend on which nerves are injured
Median – “Ape hand” deformity, inability to oppose thumb
Axillary – inability to abduct the arm
Ulnar – “Claw hand” deformity
Musculocutaneous – inability to flex forearm
Radial – wrist drop
50
Long Thoracic Nerve Dysfunction
Scapular winging
Serratus anterior muscle (long thoracic nerve branches from C5-C7, ~C8)
Long thoracic nerve palsy allows the dorsal protrusion of the scapula
Traumatic in nature
Viral/inflammatory?
51
allows the dorsal protrusion of the scapula
Long thoracic nerve palsy
52
Axillary Neurovascular Injury
Abduction of the arm on the arm board > 90 degrees
Head of the humerus into the axillary neurovascular bundle
Compression and stretch injury
Compression/occlusion = decreased perfusion
53
Mastectomy procedures can cause which nerve injury?
Axillary Neurovascular Injury
54
Abduction of the arm on the arm board > 90 degrees
Axillary Neurovascular Injury
55
Muscular men with large biceps are susceptible to
median nerve injury if the arm is fully extended during surgery
56
Median Nerve Neuropathies
most common in
men between: 20 - 40 yrs.
Men with large biceps and decreased flexibility
57
Prevention of complete extension at the elbow contributes to
Median Nerve Neuropathies
(Creates a shortening of the median nerve over time)
58
Usually, motor dysfunction doesn’t readily resolve with which nerve injury?
Median Nerve Neuropathies
~80% motor dysfunction still present 2 years post injury
59
IVs in the antecubital fossa area are a/w which nerve injury?
Median Nerve Neuropathies
60
nerves become ischemic if stretched ___ of their resting length which can ...
>5%
kink penetrating arterioles & exiting venules
↓
perfusion pressure
61
Full extension of the elbow stretches chronically contracted ___ and promotes ischemia (at the level of the __)
median nerves
elbow
62
Arm Support
support/pad the forearm and hand to prevent...
full extension
63
Radial Neuropathies are (Less/More) common than median neuropathies
more
64
Radial Neuropathies
usually compression of the nerve @ mid-humerus area (arising from roots C6-8 and T1)
Surgical retractors: compress radial nerve (bars holding abdominal retraction)
Lateral position (impinged by overhead arm boards)
Unsupported arms/ poles / **repeated cycling of the BP** cuff
65
Radial nerve injury: more often by
median nerve injury: mostly due to
radial: direct compression
median: stretch
66
T/F
NIBP is a/w injury of the median nerve.
False
more closely a/w radial never injury
67
Nerve Injury Presentation
Radial, Ulnar, Median
Radial got that limp wrist 👀
68
Arm board use
69
Lower Extremity Neuropathies
Common peroneal
Sciatic nerve
Obturator nerve
Lateral femoral cutaneous nerve
Femoral nerve
70
Hip
Excessive flexion or abduction
Flexion: injure lateral femoral cutaneous
abduction: obturator nerves
71
Obturator Neuropathy
Hip abduction >30 degrees can cause strain on obturator nerve
Excessive hip flexion of thigh can cause compression
Excessive traction in abdominal Sx
Motor dysfunction is common
Inability to adduct the leg with decreased sensation over the medial side of the thigh
72
Obturator passes through...
through the pelvis and out the obturator foremen
73
Hip flexion >90 ° causes
laterally displaces anterior superior iliac spine
&
stretches inguinal ligament
74
T/F
Lateral Femoral Cutaneous Nerve injury results in motor disability.
False
only sensory fibers
But can have:
disabling pain
dysesthesias of the lateral thigh
75
Prolonged hip flexion >90° can cause ischemia of
Lateral Femoral Cutaneous Nerve
76
Lateral Femoral Cutaneous Nerve
1/3 of the nerve’s fibers pass through...
the inguinal ligament as it passes through the thigh (originates at L2-3)
77
Sciatic & its branches
-common peroneal (fibular)
-tibial nerves
cross which joints?
the hip and knee joints
78
Sciatic & its branches
-common peroneal (fibular)
-tibial nerves
are stretched by:
hyperflexion of the hips and extension of the knees
79
Sciatic Nerve is
stretched when...
external rotation of the leg
80
Sciatic and its branches:
common peroneal (fibular)
tibial nerves
81
Usually associated with direct pressure of the lateral leg, just below the knee
Peroneal Neuropathy
82
The peroneal nerve wraps around the...
head of the FIBula
83
Peroneal Neuropathy
causes
leg holders (candy canes)
-hold the leg and foot
-Impinge nerve around the head of the fibula
84
can cause foot drop
Pressure on Peroneal Nerve
85
Saphenous Nerve Injury
when the medial tibial condyle is compressed by leg supports
difficult forceps delivery or by excessive flexion of the thigh to the groin
Muscle cramps & Tightness
difficult mobility
86
Physiological changes related to change in body position are mostly from...
**gravitational effects** on cardiovascular and respiratory systems
redistribute blood within the venous, arterial, and pulmonary vasculature
87
(In an awake pt)
Changing from erect to supine ___ venous return and stroke volume.
What happens after?
increases
Increased preload = PNS stimulation to adapt HR & contractility
88
can reduce venous return (preload) when in the supine procedure
Obesity, pregnancy, and abdominal tumors
(big belly)
89
Starling’s Law
heart matches cardiac ejection to the dynamic changes occurring in ventricular filling and thereby regulates ventricular contraction and ejection
90
Jackknife position
91
Pulmonary changes in Supine
functional residual capacity and total lung capacity are reduced due to changes to the diaphragm
92
Pulm response in supine is exaggerated in
obese patients
93
Anesthesia and muscle relaxants further reduce __ & __ due to diaphragm position with ___
FRC & TLC
relaxation
94
Trendelenburg position also (increases/decreases) lung volumes.
decreases
95
Any position that limits movement of the diaphragm, chest wall or abdomen may:
increase atelectasis
intrapulmonary shunt
96
Variations of Supine
97
Pre-op considerations
98
Supine
Upper body
on back with pillow/donut under head
Arms: boards/tucked; (< 90° ); supinated (palm up)
If at side must be padded and tucked
additional padding under elbow
Check fingers
Check IV lines and SaO2 probe
99
Supine
Resp changes
FRC decreased by 20%
Abdominal contents limit diaphragm movement
GA decreases muscle tone
Small airways close sooner → hypoxia
VQ changes cause shunting → hypoxia
Compression of the IVC
Obesity and pregnancy problems
100
T/F
Supine position can contribute to alopecia
True
Pressure on occiput → alopecia
Pad back of head
Check often in long cases
101
Supine
lower body
Keep hips and knees slightly flexed
Blanket/ pillow under knees
Cervical, thoracic and lumbar spines should be in straight alignment
102
Supine
if using arm boards
Padded
palms up (supinated)
< 90-degree
103
Complications of Supine
Peripheral neuropathies can occur in any position
Backache
Ischemic pressure injuries
Pressure Alopecia
Pressure-Point issues
104
Alopecia in Supine
Prolonged compression of hair follicles
↓
hair loss
Pain and swelling where the occiput has been supporting weight
tight face mask straps
hypoTN
hypothermia
105
Supine pressure point issues
Hypotherm & vasoconstrictive hypoTN
Heels
Sacrum
Elbows
106
Check legs when patient in supine to make sure...
legs are UNCROSSED
107
Arm restraint too tight leads to
compresses the anterior interosseous nerve (branch of the median nerve) in the upper forearm
carpal tunnel like sydrome
108
Can resemble compartment syndrome in the lower extremity
anterior interosseous nerve compression (branch of the median nerve)
ex: Arm Restraint too tight
109
Nerve Injury and Supine Position
Brachial plexus neuropathy
Sternal retraction
Long Thoracic Nerve Injury
Axillary trauma from humeral head
Radial nerve compression
Median Nerve Dysfunction
Ulnar Nerve Neuropathy
Back pain
Compartment syndrome
110
chest roll is placed
caudad to the downside axilla
111
the chest rolls lifts the thorax enough to
relieve pressure on the axillary neurovascular bundle
112
Helps prevent decreases in blood flow to the hand and arm
chest roll
113
Decreases shoulder pain after postop
chest roll
114
flexed lateral decubitus
115
flexed lateral decubitus flexion should be
under the iliac crest
116
flexed lateral decubitus positioning
Chest roll
Neck neutral
Pillow between knees and flexed
Padding under ankles/feet
117
the flank and thorax are horizontal in what positioning
flexed lateral position
118
feet and legs in flexed lateral position
Feet/legs below the atria causing pooling of blood
119
flexed lateral position can cause
lumbar stress
120
flexed lateral position is used for
thoracotomy
121
kidney surgery positioning
Lateral jackknife with elevated kidney rest
122
lateral decubitus dependent lung VQ mismatch
underventilated
more perfusion
123
lateral decubitus non dependent lung
over ventilated
less perfusion
124
VQ mismatching can cause
hypoxia
125
lithotomy position
Patient is supine with arms extended laterally <90 °
Each lower extremity is flexed at the hip (about 90°) and knees bent parallel to the floor
126
in lithotomy position, extremities should be
elevated and lowered slowly and together
127
when is lithotomy position used most often
GYN and Urology cases
128
hip flexion > 90º in lithotomy position can increase
stretch of the inguinal ligaments
129
how should legs be moved when positioning patient in and out of lithotomy
move legs at the same time
130
low lithotomy
About 30-45 degrees
Reduces perfusion gradients
131
high lithotomy
Suspend the patient's feet high with stirrups
Patient’s legs almost fully extended on the thighs flexed 90° or more on the trunk
132
significant uphill gradient for arterial perfusion to the feet
high lithotomy
133
high lithotomy can cause
Stretch of sciatic nerve
Compression of femoral canal by inguinal ligament
134
exaggerated lithotomy
Pelvis flexed ventrally on the spine, thighs forcibly flexed on trunk and lower legs aimed skyward
Associated with compartment syndrome
135
lithotomy can impair
impair ventilation due to upward pressure
More prominent in obese patients
136
most common problem with lithotomy
Nerve Injuries: Sciatic, common peroneal, femoral, saphenous and obturator
137
hand injury risk
lithotomy
138
Common peroneal nerve damage
Occurs from compression of lateral aspect of fibula head (improper padding against stirrups)
FOOT DROP
139
elevating and flexing simultaneously avoids
stretching of one side of the nerve
140
> 4 hours in lithotomy
increases risk of injury
Ischemia, edema to skin and muscles
141
femoral nerve injury causes
Excessive angulation of the thigh on the abdomen
Excessive traction during abdominal surgery
142
femoral nerve injury can cause
Decreased flexion of the hip
Decreased extension of the knee
143
femoral nerve injury causes loss of sensation over the
superior aspect of the thigh
medial or anteromedial side of the leg
144
Perfusion to an extremity is inadequate
compartment syndrome
145
characteristics of compartment syndrome
Characterized by ischemia, hypoxic edema, elevated tissue pressure within fascial compartments and extensive rhabdomyolysis
146
which positions can cause compartment syndrome
Lateral position(arm) and lithotomy (legs)
147
compartment syndrome is associated with
Systemic hypotension and loss of driving pressure to the extremity (elevation)
Vascular obstruction from excessive flexion, knee or pelvic retractors
External compression from straps
148
common factor of lithotomy for > 5 hours
compartment syndrome
149
prone position is used for
posterior fossa of the skull, posterior spine, buttocks and perirectal and lower extremities (Achilles)
150
how should arms be placed in prone position
Arms at side or “surrender position” < 90° to prevent stretching of brachial plexus
151
supine to prone
152
how is patient moved supine ➔ prone
Patient is log rolled gently so there are no abnormal movements or twisting of body parts
153
Chest rolls from below clavicles to iliac crest
in prone position to provide adequate lung expansion and help alleviate pressure on abdomen
154
prone positioning
Pillow under lower legs and ankles help flex knees and prevent pressure on toes
Head on special pillow with cut out area free of pressure on face/eyes
Head positioned to side may impair drainage on one side or neutral
Elastic stockings and active compression to minimize pooling of venous blood
155
prone position cardiac
Compression of abdominal viscera can cause:
- Pooling of blood in extremities
- Decreased preload, CO, BP, SV
156
cardiac changes in prone position
increased SVR and PVR
157
pulmonary changes in prone position
Decreased total lung compliance
Increased work of breathing
ETT can be dislodged
158
blindness from retinal ischemia
prone position
159
prone position eye indications
blindness from retinal ischemia
ION- Ischemic optic neuropathy
Corneal abrasions
160
Reverse Trendelenburg can be used for
Cholecystectomy, head and neck procedures
161
Shifts the abdominal contents caudad
reverse trendelenburg
162
May have hypotension may result in decreased venous return and perfusion to brain
reverse trendelenburg
163
Facilitates exposure, aids in breathing (increased FRC)
reverse trendelenburg
164
Causes further pressure upwards on diaphragm from abdominal contents and further decreases lung expansion
trendelenburg
165
Increases ICP by decreasing venous drainage
Increased IOP (pt with glaucoma)
trendelenburg
166
increased risk of aspiration
trendelenburg
167
Mendelson syndrome
aspiration of > 25cc of gastric contents with a pH of < 2.5
168
physiologic effects and risks associated with Trendelenburg position
Further increases translocation of blood to central compartment (along with lithotomy)
Intracranial and intraocular pressure increases
169
pulmonary changes in trendelenburg
Decrease in pulmonary compliance, FRC and vital capacity
170
What injuries can occur to the eye?
corneal abrasion is most common
Chemical injury, direct trauma (pressure and crush), blurred vision
171
Flexion of the head may move the endotracheal tube
toward the carina
172
extension of the head moves the ett
away from the carina
173
Sudden increases in airway pressure or oxygen desaturation may be caused by
mainstem bronchial intubation.
174
head down vs head up positions
175
sitting position is used most often for
posterior fossa, cervical spine, shoulder or neck surgery
176
sitting position causes pooling of blood
in the lower extremities (compression stockings)
177
decreases venous return and decreased cardiac output (20-40%)
sitting position
178
sitting position pulmonary changes
Increased lung volumes
Decreased work of breathing
179
awake vs anesthetized in sitting position
180
flexion of the head in beach chair position
Flexion of the head may obstruct the internal jugular and cause cerebral venous engorgement or hypoperfusion (swelling in the face, eyes
181
extension of the head in beach chair position
can impair cerebral blood flow causing cerebral ischemia, obstruction of ETT and pressure on the tongue
182
Cerebral vasculature dilates and constricts to maintain
constant blood flow to the brain
183
CPP=
MAP - ICP (or CVP)
184
Autoregulation occurs when MAP in between
50 and 150 m Hg
185
Poorly controlled HTN the CPP curve is shifted
higher to the right
186
BP in the arm is similar to ____________
CPP in the absence of ICP
187
beach chair MAP and BP in the arm
is higher than Cerebral perfusion
188
where is CPP monitored
at external auditory meatus (represents the base of the brain)
189
CPP is about
which is about 20 cm above the heart (15 mm Hg difference)
190
blindness and stroke due to
inaccurate BP
191
1 mm Hg decrease/
1.35 cm height
192
20 cm ~ ____________ mmHg change
15 mmHg change
193
sitting position potential complications
Venous air emboli
Hypotension (fluids, vasopressors, decrease agent)
Brainstem manipulations resulting in hemodynamic changes
Risk of airway obstruction
Decrease venous return (stockings or compression devices)
Macroglossia (avoid chin against chest)
194
midcervical tetraplegia
Hyperflexion of the neck, with or without rotation of the head
Stretching of the spinal cord resulting in compromise of the vasculature of the midcervical region
195
mid cervical tetraplegia paralysis below
the level of the 5th cervical vertebra
196
position for mid cervical tetraplegia
Sitting position
197
Prolonged head flexion for intracranial surgery in the supine position can cause
mid cervical tetraplegia
198
venous air embolism is caused by
open venous system above level of the heart
199
detecting venous air embolism
by listening to heart sounds with Doppler at R 2nd intercostal space
200
s/s of venous air embolism
sudden decrease in CO2, hypoxia, arrhythmias, hypotension and a “millwheel murmur” (usually a late sign)
201
venous air embolism treatment
202
durant's position
203
face masks can cause
pressure damage over nose
204
facial nerve damage can occur from
fingers over mandible
205
Face straps can cause injury or even necrosis to
face, ears and eyes and alopecia
206
visual injuries
207
patients at risk for visual injuries
DM
Smokers
Obese
ETOH abuse
Anemic
HTN
208
Wilson Frame
head is lower than the heart
209
Potential Etiology of POVL
acute venous congestion of the optic canal
210
Obesity can increase
intraabdominal pressure in prone patients
211
how to reduce post-op vision loss
Reduce venous congestion in the optic canal
Keep head above the heart or at the same level
Colloids vs Crystalloids
Reduce intra-abdominal pressure
Limiting duration of surgery
212
The retinaculum stretches from ___ to the ___
the medial epicondyle
olecranon
213
How does elbow flexion affect the retinaculum?
stretches the retinaculum and puts a lot of stress on the nerve as it passes underneath
214
Radial Nerve Injury
Causes
S/S
**compression** against spiral groove of humerus and other object (i.e. ether screen or excessive cycling of NIBP)
wrist drop, weakness of abduction of thumb, and loss of sensation in web space between thumb and index finger
215
This nerve carries only sensory fibers, so no motor disability occurs
Lateral Femoral Cutaneous Nerve
But can have:
disabling pain
dysesthesias of the lateral thigh
