Exam 1: Positioning Flashcards
Documentation of operative positioning should include (4):
Baseline ROM
Intra-op position
Padding, frame, equipment
Checks & frequency
OR length and weight limits (old and new):
80.7 inches
Old: 136kg (300lb)
New: 270kg (600lb)
Patient’s torso should be centered over which part of the bed?
The column
Always make sure the OR table has this before transferring patient:
Draw sheet
Last step of transferring pt to table:
Safety/reminder strap
Advantages of supine position:
Access to airway
Access to arms
Less physiologic changes
Head support in supine:
Pillow under head (allows sniffing position, avoids excess extension/flexion)
Arm position in supine:
Tucked, (using draw sheet, hand against thigh) or out using arm boards (less than 90º abduction, hands supinated, well padded)
Lower extremity position in supine (5):
Heels padded and on bed, not hanging Feet/legs uncrossed Hips/knees slightly flexed Pillow under knees SCDs/TEDs
Mechanisms of nerve injury:
STICK: Stretch Transection Ischemia Compression Kinking
Supine position injuries to brachial plexus (4):
Arm extension past 90º (stretch)
Shoulder brace pressed on clavicle (compression)
Arm falling off table (stretch)
Neck extension (stretch)
Two fixed points of brachial plexus pathway:
Vertebral foramina fascia
Axilla
Sitting position injuries to brachial plexus:
Shoulder sagging with relaxation (stretch)
Lateral position injuries to brachial plexus:
Clavicle/scapula/humerus shifted excessively forward (stretch)
Most common peripheral nerve injury:
Ulnar
2nd most common peripheral nerve injury:
Brachial plexus
S/s of brachial nerve plexus injury:
Electric shocks/burning sensation shooting down arm
Numbness/weak arm function
Causes of radial nerve injury in supine position:
Surgical retractors
Ether screen
Arm board not level with bed
BP cuff inflation
All compression injuries!
S/s of radial nerve injury:
Wrist drop
Weakness in thumb abduction
Numbness of fingers 1, 2, 4
Inability to extend arm at elbow
Causes of ulnar nerve injury in supine position:
Entrapment from arm extension
Stretch from severe elbow flexion
Compression against bed
S/s of ulnar nerve injury:
Inability to abduct or oppose 5th finger
Weak grip on outside of fist
Loss of palmar sensation
4th/5th fingers
Claw hand
CV changes in supine position (3):
Minimal overall
Initial increased return to heart (inc. preload, SV, CO, BP) but baroreceptors compensate
Exception: abdominal masses or pregnancy - pressure on IVC may decrease venous return
Ventilatory changes in supine position:
Decreased FRC (800ml) Muscle relaxants also decrease lung volume
CBF changes in supine position:
Minimal change
Advantages of Trendelenberg (4):
Treats hypotension (short term)
Improves lower abdominal exposure
Prevents air embolism
Makes CVC placement easier
Equipment caution in Trendelenberg:
Shoulder braces - use extreme caution and position them out on the joints, not at the root of the neck
How much blood does Trendelenberg return to central circulation?
1L
CV changes in Trendelenberg:
Reduced blood to LEs
Compression of heart possible
Baroreceptors cause peripheral vasodilation, bradycardia
What happens when pt returns from Trendelenberg to supine?
Blood pools in extremities –> hypotension
Ventilation changes in Trendelenberg (5):
Increased work of breathing d/t pressure from abdo contents
Perfusion > ventilation at apex of lung
Easier R mainstem ETT d/t shifting abdominal contents, flex/extend of head
Inc. risk of aspiration
Face/airway edema –> airway obstruction
CBF changes in Trendelenberg (3):
Increased intracranial vascular congestion
Increased ICP
Increased intraocular pressure
Patients who are not good candidates for Trendelenberg:
Glaucoma
CNS disease
Advantages of reverse Trendelenberg:
Increases upper abdomen exposure
Useful for shoulder, neck, intracranial surgery
Equipment caution with reverse Trendelenberg:
Footboard use for extended time can kink anterior tibial nerve and lead to foot drop
CV changes in reverse Trendelenberg (4):
Reduced preload, CO, BP
Compensatory increase in SNS tone, SVR, HR
RAAS activation
Venous pooling in LEs
% change in CO and HR in reverse Trendelenberg:
20-40% decrease in CO
30% change in HR (if not blunted by anesthesia)
Ventilation changes in reverse Trendelenberg:
Increase in FRC
Easier ventilation
CBF changes in reverse Trendelenberg:
Decreases proportional to degree of tilt (up to 20%)
Hip and leg abduction angles in lithotomy position:
80-100º flexion at hips
30-45º abduction of legs from midline
Possible nerve injuries in calf support lithotomy position (4):
Femoral n. (kink)
Sciatic n. (stretch)
Saphenous n. (compression)
Common peroneal/fibular n. (compression)
Three types of lithotomy supports:
Calf support
Candy cane stirrups
Knee crutches
Possible nerve damage with candy cane stirrups:
Femoral n. (kink)
Sciatic n. (stretch)
Common peroneal nerve (compression)
Possible nerve damage with knee crutch stirrups:
Popliteal n. (compression)
Most common three lower extremity nerve injuries:
Common peroneal (78%)
Sciatic (15%)
Femoral (7%)
S/s of common peroneal nerve injury:
Foot drop
Inability to evert foot
Loss of dorsal extension of toes
S/s of sciatic nerve injury:
Weakness or paralysis of muscles below knee
Numbness of foot, lateral half of calf
Foot drop
S/s of femoral nerve injury:
Loss of hip flexion, knee extension
Decreased sensation on superior thigh
S/s of saphenous nerve injury:
Medial and anteromedial calf parasthesias
Risk factors for LE compartment syndrome:
Long procedures
Lithotomy or lateral decub position
CV effects of lithotomy:
Elevation of legs transiently increases preload/CO/BP
Perfusion pressure to extremities lowers ____ for each _____ that they are raised above the heart.
2 mmHg for each 2.5 cm
Ventilatory effects of lithotomy:
Abdominal contents may get pushed up by hip flexion and decrease compliance/TV/VC
CBF effects of lithotomy:
Transient increase in CBF and ICP when legs are elevated
Keep pressure off abdomen in prone position in order to:
Improve caval return/perfusion
Frame used for prone position:
Wilson frame
Special table used for prone position:
Jackson table
Steps to take after turning prone (5):
Check breath sounds again
Monitors on/working
Check IV, A-line, etc
Check pressure points
Check neck alignment
Head position in prone (4):
Side to side if patient is sedated
Head supported face-down for GA, with weight on bony structures
Eyes, ears, nose free of pressure
Neutral neck alignment!!
Arm position in prone (4):
Abducted less than 90º
Extra padding at elbow
Watch shoulders - keep from sagging
Tucked at sides
What is thoracic outlet syndrome? What is a quick test for it?
Impingement of IJ, EJ, lymphatics by the clavicle when arms are raised
Test: Put hands behind head for 2 mins - look for dec. pulses, numbness, tingling
CV changes in prone:
Hypotension d/t caval/aortic compression
Hypotension d/t venous pooling in LEs
Biggest immediate physiological concern with prone position:
Hypotension!!
Can lead to blindness when combined with pressure on face/eyes
Ventilatory changes in prone (2 big ones, with details):
V:Q mismatch:
Posterior ventilation > perfusion
Anterior perfusion > ventilation
Diaphragm displaced cephalad; compliance decreases, airway pressure increases, WoB increases
CBF changes in prone:
Turning head obstructs venous return, increasing ICP
Excessive flexion/rotation obstructs verts
Uses of lateral decubitus position:
Thoracotomy, kidney, shoulder, hip surgeries
Arm position in lateral decubitus:
Dependent arm on arm board, perpendicular to torso
Non-dependent arm supported over bedding or another armrest
Leg position in lateral decubitus:
Padding between knees
Dependent leg flexed
Padding on bed below dependent leg
Torso position in lateral decubitus:
Axilla roll under side chest
Anterior/posterior support - rolls or bean-bag support
Safety strap between head of femur and iliac crest
CV changes in lateral decubitus:
Minimal changes unless venous return is obstructed (kidney rest)
BP measurements will be different in dependent vs. non-dependent arms
Ventilation changes in lateral decubitus, related to pt status/ventilation:
Biggest V/Q mismatch of any position
In awake/spontaneously breathing pt: dependent lung better vent/perf but lung volumes decreased
In asleep/spontaneously breathing pt: nondependent lung better vent, dependent lung better perf
In asleep/mechanically ventilated pt: nondependent lung overvented, dependent lung overperfused
CBF changes in lateral decubitus:
Minimal change unless head extremely flexed
Advantages of sitting position:
Facilitates venous drainage
Excellent surgical access
Cranial, shoulder, humeral surgery
Head position in sitting:
Head in pins or taped in place
Avoid excessive cervical flexion - obstructs venous outflow - at least 2 FB between mandible + sternum
Negative sequelae of excessive cervical flexion (4):
Cerebral hypoperfusion/venous congestion
Stretch injury to cervical nerve roots
Obstruction of ETT
Pressure/ischemia of tongue
Arm position in sitting:
Avoid pressure on frame
Support the arms to avoid pulling/traction on shoulders (brachial plexus injury)
CV changes in sitting:
Pooling of blood into LE s –> dec preload, CO, BP
Hypotension
HR/SVR increase as compensatory change
Ventilatory changes in sitting:
Lung volumes/capacities increase - easier WOB
CBF changes in sitting:
Gravity decreases CBF, ICP
Biggest risk with sitting position:
Venous air embolism
S/s of VAE (5):
Change in heart tones (“wind mill” murmur) via doppler
Desaturation/decreased ETCO2
Nitrogen in exhaled gas
Circulatory compromise
Cardiac arrest
Detection of VAE:
TEE
Precordial Doppler ultrasound
Treatment of VAE (5):
Surgical: flood surgical field with NS, wax bony edges, achieve hemostasis
D/C nitrous oxide
100% O2, PEEP
Trendelenberg
Aspirate air from RA via catheter
