Positioning Flashcards
Positioning is shared responsibility, but ultimately positioning is determined by?
surgeon
What is CRNA’s primary responsibility (3)?
protect aw, vascular access and promote homeostasis
Are all PNI preventable?
no
Which PNI most common? Second most common? Most common LE PNI?
ulnar nerve, brachial plexus close second, sciatic
Supine is also called?
dorsal decubitus
What is most common operative position?
supine/dorsal decubitus
Arms should never be abducted > ____ degrees?
90
Arms should always be supinated or pronated? Or?
supinated, palms up
at side, palms in
What can be injured if arms are abducted > 90 and pronated?
brachial plexus
How can the lumbar be supported in supine position? (3)
slight flexion hips/knees, pillows under knees, elastic compression stockings/SCDs
Why does the lumbar need to be supported in surgery and supine position?
ligaments of vertebral column relax w/ anesthesia
What can cause brachial plexus injuries in surgery? (4)
abduction of arms >90, compression of neck, shoulder braces/pads, cardiac surgery - instruments that open chest
What injury can result if arms are pronated and why?
ulnar injury, d/t compression of cubital tunnel
What are possible complications of supine position? (5)
pressure alopecia, backache, aortocaval compression syndrome, skin breakdown/ulcers, circulatory compromise
What is aortocaval syndrome?
compression of abd aorta and IVC in pregnant women from lying flat on back, causes hypotension and fetal compromise
What variation on supine can help alleviate low back pain?
lawn chair position
What are the effects of trendelenburg position? Increases, decreases, why?
increased venous return: increased preload, increased venous return increased ICP/decreased CPP - vascular congestion, increased intraocular pressure, increased PIP
abd contents/diaphragm moves cephalad, compresses lungs: decreased FRC, decreased pulmonary compliance, r/o endobronchial intubation
Fluid shifts in Trendelenburg can cause what complication? And it can cause what?
Edema: aw, tongue, pharanyx, face, sclera
Can cause aw patency issues.
If worried about effects of Trendelenburg position on aw patency what interventions can you perform? (2)
check for cuff leak, listen to lung sounds
What are the anesthetic concerns of Trendelenburg? (7)
sliding, alt. cardio/pulm function, PNI, aw edema, compartment syndrome, regurg/asp, ETT migration
How can you lower the risks of Trendelenburg? (8)
anti skid pads, appropriate padding - face, confirm ett, conservative use of fluids, post-op O2, OGT/suctioning, ensure patent IVs, vent modes (OC vs VC)
What surgeries are facilitated by reverse Trendelenburg? Why?
upper abd, head and neck, shoulder, intracranial
promotes venous drainage, decreases blood/bleeding, movings abd contents caudad
What surgeries are facilitated by lithotomy?
GYN, rectal, urology
What are some concerns of lithotomy position? (5)
watch for crush finger injuries, raising/lowering legs (do it at the same time, slowly), PNI, intubation difficulties, ask pt to position themselves by moving down
What are some possible PNI and causes in lithotomy position?
candy cane - common peroneal - compression of lateral head of fibula, femoral, sciatic
knee crutch - popliteal, tibial nerve common peroneal nerve
excess hip flexion: obturator, lateral femoral cutaneous
What are CV/respiratory consequences of lithotomy? And why?
displacement of abd contents cephalad, legs elevated - increased venous return:
decreased lung compliance, decreased Tv, increased PIP, increased CO
What LE complication can occur in lithotomy position and why?
compartment syndrome, d/t inadequate extremity perfusion, extensive rhabdomylosis - increased tissue pressure, occurs from long surgical procedures > 2-3, people with low BMI and smokers
What pt factors increases risk of complications in lithotomy position? (3)
low BMI, smoking, prolonged surg. ( > 2-3 years)
What are some risk reduction strats for lithotomy position? (4)
attention to hands/fingers, intraoperative repositioning, lower legs occasionally, avoiding excessive hip flexion/abduction,
What types of surgeries use lateral decubitus position?
thorax, kidney, shoulder, ortho, spinal
When should eyes be taped?
after intubation
What is an anesthetic concern in lateral decubitus position? Intervention and why its done.
dependent side, place axillary roll, just inferior to axilla, 7th/9th rib
avoids compression of axillary neurovasc structures
What intervention helps monitor circulation in dependent arm?
check pulse in dependent arm via pulse ox
How will NIBP differ in dependent arm?
increased
What LE PNI can occur in lateral decubitus position and intervention to prevent it?
common peroneal, saphenous
pad knees
What are pulm. consequences of lateral decubitus position? Why?
V/Q mismatch d/t dep lung better perfused, worse ventilated; non-dependent lung worse perfused, better ventilated
Contrast high V/Q mismatch vs low.
High - lots of ventilation, low/little perfusion. High O2. Aka deadspace.
Low - lots of blood flowing, but little to no ventilation. Low O2. Aka shunting.
Why is the dependent lung better perfused?
gravity
Compare contract differences in anesthetized vs not anesthetized pts lungs in lateral positioning.
awake/spont breathing: dependent lung better V and Q but lung volumes are decreased (Tv, FRC)
anesthetized/spont breathing: nondependent lung better V, dependent lung better Q (mismatch)
anesthetized/mech. vent.: nondependent lung over-V and dependent lung over-Q (worse mismatch)
Prone positioning is also called?
ventral decubitus
When pt is going to be in prone positioning, where should the pt be intubated?
stretcher (also when foley, temp probe, IV done, bite block placed)
What should remain connected to pt and where when proning pt? Why?
pulse ox, on dependent arm
Whats the last thing that is disconnected before proning pt?
ett
When proning a pt what is the job of the CRNA?
coordinating movement of head
Describe how pt’s legs, face, arms and abd should be positioning in prone.
legs: flexed, padded, compression hose - venous pooling
face: down or to the side, pillow, neck natural alignment
arms: tucked or above head < 90 degrees - prevents brachial plexus injury, padded elbow prevents ulnar nerve injury
abd: avoid pressure - causes decreased FRC, pulm. compliance, increased PIP, use bolsters or firm rolls clavicle to iliac crests
Immediately after a pt is proned what should be done next? (4)
reconnect vent, reapply monitors, check ETT (etCO2, lung sounds, Tv, PIP), check alignment of head and neck
What are Mayfield pins? Who is responsible for them? What are some concerns?
for cranial/cervical surgeries, ensures correct alignment of pt and that they do not move during surgery. surgeon responsible for count when moving.
make sure no metal parts are putting pressure on eyes, nose or chin, and not compressing neck.
What is the significance of abdominal pressure in prone positioning?
external pressure on abd elevates intrathoracic and intraabd pressure. increased pressure on IVC, compressed IVC -> decreased venous return, decreased CO.
significant bc excess bleeding in surgical field may occur but not be noticed
What is perioperative visual loss, how does it occur, things to be mindful of (5)?
painless vision loss after surgery, ischemic optic neuropathy (ION) and central retinal artery occlusion (CRAO) - from direct, external pressure to face during prone positioning, fluid shift.
mindful of: hypotension, anemia, increased crystalloid use, blood loss, long duration
What respiratory effects does prone positioning have?
Improved V/Q mismatch
What cardiovascular affects occur w/ proning a pt?
IVC/aorta compressed, leads to hypotension. Also, venous pooling in LE leads to hypotension. Both lead to decreased preload, CO, BP.
What affects can proning have on cerebral blood flow
turning head obstructs venous drainage leading to increased cerebral volume and increased ICP. excess flexion/turning causes obstruction to vertebral artery flow.
spinal cord injury can also result from stretch.
What equipment can help lower pressure on the abd during proning?
Wilson, Jackson, Allen frames
Genitalia should be free of ______ during proning.
Pressure
Populations that are difficult to prone (3)
obese, resp. compromise, pts w/ difficulty repositioning
Sitting position is used it what types of surgeries? And why?
post cerv spine, post fossa d/t excellent surgical exposure, decreased blood in surgical field, reduced blood loss, better mobilization of shoulder
What are some anesthetic advantages of sitting position? (3)
aw access, reduced facial swelling, improved ventilation
Describe sitting positioning’s arms, head, legs.
head: pinned or taped, arms: slight elevation of shoulders, padded, knees: slightly bent - reduce sciatic nerve stretching, feet: supported and padded
What are the risks in sitting position? (7)
VAE, quadriplegia, spinal cord infarction, hemodynamic instab. - stroke/death, pneumocephalus - air/gas in head, macroglossia - d/t pressure on tongue, may need trach, PNI
What are the hemodynamic effects of sitting position?
Pooling of blood in LE, causes hypotension from reduced venous return, reduces CO.
What interventions can you do to mitigate hemodynamic effects of sitting position? (5)
incremental positioning, IVF, vasopressors, adjusting anesthesia (fewer sedatives, nerve block instead, or TIVA), SCDs/TED hose
What are some anesthetic concerns for the head and neck in sitting position?
hyperextension of neck leading to cervical injuries.
flexion causes: impedance of blood flow - leads to hypoperfusion or venous congestion in brain, blocking ett - impedance to breathing, pressure on tongue, midcervical tetraplegia - ischemia to spinal cord
Beach chair position is used for what type of surgery?
shoulder surgery
A 1 cm rise causes a _______ drop in BP.
0.75 mmHg drop (a MAP of 65 in the arm is 50 in the head, aka a 20 cm rise)
When can a VAE happen?
any time surgical site above level of heart
What are signs of VAE? (8) What about if pt is awake, spont breathing?
wind mill murmur, dysrhythmias, hypotension, desaturation, decreased etCO2, N2 in exhaled gas, circ compromise, cardiac arrest
dyspnea, coughing, breathless, light headed, chest pain, feeling of doom
How much air is lethal in VAE?
200-300 mL
What does a VAE cause?
right heart failure
What EKG changes will you notice with VAE? (3)
kink in T wave, tachy dysrhythmias, ischemia
How to monitor for VAE? (3)
precordial steth, doppler, TEE
Whats treatment for VAE? (11)
flood surgical field with NS, apply wax to bony edges, close open vessels, D/C N2O, place pt on 100% O2, PEEP, trendelenburg, aspirate air from RA w/ catheter, vasopressors (dobut/norepi - anything that does not increase vasc resistance), hyperbaric O2, CPR/resuscitation
What are some examples of high risk surgeries for VAE?
sitting crani, posterior fossa/neck, laprascopic surg, total hip arthroplasty, C-section, central line placement, craniosynotosis
Brachial plexus: where is it and how can it be injured?
Network of nerves in shoulder, travels through cervical vertebrae and through axillary fascia.
Injured by kink/stetch/compression: abducting > 90, compressing clavicle or soft tissue of axilla, neck extension, head turning side to side, arm board falling off table, shoulder braces, sternal retractors, compression against thorax
Whats the deficit if brachial plexus is injured? (3)
limp/paralyzed arm, lack of muscle control in shoulder/arm/hand/wrist, lack of sensation in arm or hand
Ulnar nerve: where is it and how can it be injured?
Groove between olecranon of ulna and medial epicondyle of humerus.
Injured from compression of nerve in cubital groove in elbow, stretch injury from extreme flexion, compression against bed/IV pole, misplaced BP cuff, dislocation over medial epicondyle w/ pronation causing stretching
What deficits w/ ulnar nerve injury?
inability to abduct/oppose 5th finger (touch thumb), loss of grip strength, loss of sensation of 4th and 5th fingers, claw hand - from atrophy of intrinsic muscle of hand (chronic injury, not right after surgery)
How does a radial nerve injury result and what are the deficits?
external compression of nerve on lateral aspect of humerus against: surgical retracts, ether screen, mismatched arm board, repeat BP inflation, sternal retractor.
loss of extension of forearm, weak supination, loss of extension of hand (WRIST DROP) and fingers, loss of sensation of posterior forearm and part of hand
Common peroneal nerve: hows it injured and what are the deficits?
branch of sciatic nerve, runs along lateral aspect of knee. injured from compression of lateral aspect of knee against stirrup or in lateral decubitus position.
deficits are: FOOT DROP, inability to evert foot, loss of dorsal extension of toes (no sensation)
Sciatic nerve: hows it injured and what are the deficits?
excessive external rotation of hips, hyperextension of knee, pressure in sciatic notch from stretching
deficits: weakness/paralysis of muscles below knee, numbness in foot and lateral half of calf, FOOT DROP
Femoral nerve: hows it injured and what are the deficits?
injured by compression at pelvic brim by retractor or excessive angulation of thigh and external rotation of hips
deficits: loss of flexion of hip, loss of extension of knee, decreased sensation superior thigh
Saphenous nerve injury: hows it injured and what are deficits?
medial aspect of lower leg compressed against support bar
deficit: paresthesis medial and antemedial side of calf
