Positioning #2 Flashcards

1
Q

What cardiovascular changes would you anticipate in lithotomy position?

A
  • Elevation of legs increases venous return/increases preload to heart with a transient increase in CO and BP
  • perfusion to lower extremities is reduced
    • perfusion pressure changes 2 mmhg for each 2.5 cm that a given point varies in vertial height above or below the heart
  • After legs are put down, venous blood will pool in them. Always check BP after putting legs down
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2
Q

What ventilatory changes would you anticipate in lithotomy position?

A
  • Depending on the degree of hip flexion, abdominal contents may push up on the diaphragm and impede excursion
    • reducing lung compliance
    • decreasing TV and VC
    • increases risk of aspiration
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3
Q

What cerebral changes would you anticipate when putting your pt in lithotomy position?

A
  • transient increase in cerebral venous blood flow and increase in intracranial pressure with legs elevated
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4
Q

What is the Wilson frame?

A
  • frame used to prone a patient; it is open under abdomen and chest to allow for ventilation
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5
Q

What is a jackson table?

A
  • special table used if position changes are needed during the procedure
  • *the human rotisserie
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6
Q

What are the different options for head rests when pt is prone?

A
  • head rest with mirror
  • horseshoe headrest
    • watch eyes, nose, bony structures of face
    • make sure head and neck are aligned
  • Mayfield head tongs/pins (pictured)
    • watch for bolt slippage
    • want natural neck alignment
    • eyes, nose, and chin are free with nothing touching them
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7
Q

How is a patient put into prone position?

A
  • While patient is still on the stretcher:
    • induction/intubation
    • line placement
    • NGT/OGT, esoph stethescope, bit block
    • foley
    • good eye protection
  • secure everything
  • Consider disconnecting the monitors
  • Turn pt to prone postion onto OR table (you in charge of head/neck/airway
  • Once turned, check breath sounds again
    • make sure monitors are on and working
    • check IV and art line
  • Check for excessive pressure on eyes, nose, chin, upper extremities, breasts, genitals, etc
  • Chest and hips should be supported to allow for free abdomen for diaphragmatic movement and increased venous return
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8
Q

How do you position the head in prone position?

A
  • Head may be turned to side if they have adequate mobility
    • caution: obstruction of jugular venous drainage and vertebral artery flow
  • Head supported face down with its weight on bony structures
  • Neck should be in neutral alignment, not excessive flexion or extension
  • Eyes, nose, ears should all be free of pressure
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9
Q

What are the risks for the eyes in prone position?

What are the risk factors for blindness in the OR?

A
  • Corneal abrasions
    • direct trauma, dry eye, or swelling
    • treatment is antibiotic ointment, eye patch
  • Blindness
    • ischemic optic neuropathy
      • via central vein or artery obstruction
      • via sustained, direct pressure on the eye/retina
    • visual changes/ partial or complete blindness
    • Risk factors include prone position, operative hypotension, large operative blood loss, large crystalloid use, anemia, smoker, diabetic, patients with vascular pathology or HTN, males
    • Caution in spinal surgery and cardiac surgery
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10
Q

What do you do with the extremeties in prone position?

A
  • Arms:
    • on boards by the head
    • abducted less than 90 degrees
    • extra padding at elbow
    • prevent shoulder from sagging
    • watch for thoracic outlet syndrome
      • or tuck arms at sides
  • legs:
    • slightly flexed
    • compression socks/SCD
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11
Q

What CV changes would you expect with a proned patient?

A
  • IVC and Aortic compression- hypotension
  • Venous pooling in lower extremities- hypotension
    • leads to decreased preload, CO, and BP
  • Hypotension associated with the move to prone position must be anticipated, monitored, and treated as necessary.
    • prolonged hypotension in addition to pressure on the face/eyes may lead to blindness!!
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12
Q

What ventilatory changes would you expect in a proned patient?

A
  • V:Q mismatch
    • posterior would have ventilation > perfusion
    • anterior would have perfusion > ventilation
  • Cephaled displacement of diaphragm
    • decreases lung compliance
    • increased peak airway pressures
    • increased WOB
  • **Use rolls/bolsters to free chest
  • PPV overcomes compression effects
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13
Q

What cerebral blood flow changes would you anticipate in a proned patient?

A
  • Turning head obstructs venous drainage leading to increased cerebral volume and ICP
  • Excess flexion or turning can obstruct vertebral artery flow
  • spinal cord injury can be caused by stretch
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14
Q

What is lateral decubitus position used for?

What special accomodations does it require?

A
  • Used for:
    • thoracotomy
    • kidney
    • shoulder
    • hip surgery
  • Requires special positioning of:
    • head support- neutral position
      • avoid misalignment of cervical spine or stretch of brachial plexus
    • Limited pressure on dependent eye and ear
    • axillary roll placed caudad to and outside of lower axilla (pic on front of card)
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15
Q

What should you do with the extremeties when positioning your patient laterally?

Where does the safety strap go?

A
  • Arms:
    • dependent arm on a padded arm board perpendicular to torso
    • Non-dep arm supported over folded bedding or suspended with armrest
  • Legs:
    • padding between knees and flexed dependent leg (to avoid saphenous nerve injury)
    • padding on bed (to avoid common peroneal nerve injury)
  • Anterior/posterior support- bean bag/hip posts
  • Safety strap- between head of femur and iliac crest
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16
Q

What cardiovascular changes would you expect when you postion your patient laterally?

A
  • Minimal changes
  • no change to CO unless venous return is obstructed
    • if the kidney rests against the vena cava
  • Non-invasive BP cuff measurements will be different in the two arms
    • higher in dep
    • lower in non-dep
17
Q

What ventilatory changes would you expect in your laterally positioned pt?

A
  • V/Q mismatch
  • If awake and spontaneously breathing:
    • dependent lung is both better perfused and better ventilated
    • lung volumes (FRC, VC, TV) decrease
  • Anesthetized but spontaneously breathing
    • Non-dep lung better ventilated and dep lung better perfused (V/Q mismatch)
  • Anesthetized, mechanically ventilated:
    • Non-dep lung overventilated and dep lung over perfused (worse V/Q mismatch)
18
Q

What changes to cerebral blood flow would you anticipate in a pt positioned laterally?

A
  • Minimal change unless there is extreme flexion
19
Q

When is the sitting position used?

A
  • Used for:
    • cranial surgery
    • shoulder
    • humoral
  • Facilitates venous drainage
  • excellent surgical exposure
20
Q

How should you position the head when placing your patinet in sitting position?

A
  • Head should be fixed in pins or taped in place
  • avoid excessive cervical flexion (want at least two finger breadths between mandible and sternum)
    • obstructs outflow causing hypoperfusion or venous congestion in the brain
    • stretches cervical nerve roots
    • can obstruct ETT
    • can place pressure on the tongue (swelling)
  • Avoid rigid bite-block that can cause tongue eschemia
  • watch spinal alignment
21
Q

How can you ensure your patient is well positioned in sitting position?

A
  • Arms should be supported- avoid traction pulling down on shoulders
  • Buttocks should be positioned in the break of the table
  • Flex knees and hips- decrease stretch of sciatic nerve
  • compression socks/SCD
  • feet supported and padded
22
Q

What cardiovascular changes would you anticipate for a pt in sitting position?

A
  • Pooling of blood in lower extremeties decreases preload, CO, and BP
    • HYPOTENSION!!
  • HR and SVR increase as a compensatory measure (blunted by anesthetics)
  • Treatment: IVF, vasopressors, adjustments of ansethetic depth, compression socks/devices
23
Q

What ventilatory changes would you anticipate in a patient in sitting position?

A
  • Lung volumes and capacities increase
  • compliance increases
  • WOB is easier
  • Mechanical and spontaneous breathing is easier in this position
24
Q

What changes to CBF would you anticipate in a pt in sitting postition?

A
  • Cerebral blood flow decreased
  • ICP decreased
  • watch positioning which can impede arterial and venous blood flow, causing hypoperfusion or venous congestion of the brain
  • zero art line at circle of willis
25
Q

What is a major risk associated with the sitting position?

A
  • Venous air embolism is a risk any time the surgical site is above the level of the heart
  • VAE prevents venous sinuses from being able to collapse
    • can be a lethal complication
  • Signs of VAE:
    • change in heart tones (wind mill murmor)
    • new murmor
    • dysrhythmias
    • hypotension
    • desaturation
    • decreased ETCO2
    • nitrogen in exhaled gas
    • circulatory compromise
    • cardiac arrest
  • detected with TEE or precordial doppler
26
Q

Where would you hear the wind mill murmor associated with VAE?

A
  • Heard via doppler placed at the parasternal border
    • 2nd-6th intercostal space
27
Q

How is VAE treated?

A
  • Flood surgical field with NS, apply wax to cut bony edges, close any open vessles
  • D/C nitrous
  • place on 100% FiO2, peep
  • t-berg position
  • aspirate air from right atrium via a catheter