Test 1 part VIII (Positioning)

Question 1

What is the most common position for surgical procedures (head, neck, chest, abdomen, extremities)?

Answer 1

Supine

Question 2

What are anesthetic concerns r/t supine position?

Answer 2

1. Decreased FRC & TLC (due to cephalad shift of the diaphragm and abd contents)
2. Hemodynamics are maintained
3. Consider pts w/ severe arthritis, decreased C-Spine mobility, or neuropathies may need gel padding to even pressure distribution

Question 3

Utilized with surgical procedures on the spine, certain orthopedic procedures, rectal/butt procedures, and those on the posterior fossa.

Answer 3

Prone

Question 4

What are anesthetic concerns r/t prone positioning?

Answer 4

1. Risk of ETT migrating
2. Improved physiology w/ARDS (due to increased lung volumes, oxygenation, and superior V/Q matching). But avoid pressure on abdomen!!
3. Decreased risk of VAE than sitting
4. Risk for post-op visual losses

Question 5

How do you prone a patient in the OR?

Answer 5

1. Patient is anesthetized on the gurney, then log-rolled onto OR table
2. Monitor placement should allow turning & avoid unnecessary delays
3. CRNA controls airway/head/neck and coordinates turn!!
4. Potential for accidental extubation!!

Question 6

What is the effect of prone positioning on hemodynamics?

Answer 6

1. CO & BP decreased in sitting, prone, & flexed lateral positions. Lower extremities are dependent, blood pooling potential
2. Maintained if legs are in plane with torso
3. Abdomen must be free hanging & able to move with ventilation. External pressure on abdomen can elevate both intra abdominal and intrathoracic pressures.

Question 7

What are some causes of increased abdominal pressure?

Answer 7

Increased venous pressure in abdominal & spinal vessels, IVC compression, decreased CO

Question 8

What are the effects of prone positioning on pulmonary function?

Answer 8

1. Exacerbates ventilatory effects of other positions → decreased FRC & TLC
2. Potential for ETT migration or accidental extubation*
3. May be enhanced with proper positioning: bolters, wilson frame, jackson table
4. Increased ABD pressure = cephalad displacement of diaphragm = increased PIP, decreased FRC, decreased lung compliance
5. Consider PC ventilation with low tidal volume and higher RR to maintain normal EtCO2 & PIP

Question 9

What are some pressure monitoring points for prone positioning?

Answer 9

1. Ensure eyes, nose, and mouth are free from pressure and recheck q 15-30 minutes
   -Need a foam pillow supporting forehead, chin, and facial bones
2. Mirror to monitor pressure points can be used
3. Potential for skin breakdown during long cases
4. Ensure ETT free from kinks and is accessible as needed
5. Pad frontal bone, mandible, humerus, sternum, tuberosity of pelvis, patella, tibia

Question 10

Which subtype of prone is used for rectal surgeries?

Answer 10

Prone Jack-Knife

Question 11

Can be used in place of bolsters to allow for free hanging abdomen, check breasts & genitalia; allows for natural curvature of the spine for spine fixation, disc removal & replacement

Answer 11

Wilson Frame

Question 12

Allows for A/P spine surgery using same OR table
-Pt supine on table, circuit, IV tubing & monitors (except SpO2) removed to allow for 180 degree turn
-MUST ensure top of sandwich is very secure – entire frame turned 180

Answer 12

Rotisserie Table

Question 13

A position used for perineal surgeries.
-Potential for back pain secondary to loss of lumbar curvature, lumbosacral nerve stretch, & peroneal nerve injury associated with stirrups

Answer 13

Lithotomy

Question 14

What are the Pulmonary effects associated with Lithotomy Position?

Answer 14

1. Awake/Spon Ventilation: minimal effect
2. With GA with PPV: decreased compliance and Vt, increased airway pressures and minute ventilation. Flexion of the thighs compresses the abdomen, and viscera shifts cephalad. Effects are amplified with obesity!!

Pulmonary compliance and tidal volume are reduced, while PIP and dead space are increased!!

Question 15

What are the hemodynamic effects associated with Lithotomy Position?

Answer 15

BP may be normal to high due to leg elevation above the trunk.
-Gravity dependent central redistribution of blood volume (autotransfusion)
-Increased venous return = increased cardiac output
-BP decreased when legs lowered to supine position (hypovolemia)

Question 16

Used in surgical procedures involving neurosurgery and orthopedics, such as shoulder, upper extremity, clavicle, posterior fossa craniotomy. Head is fixed in pins or head support

Answer 16

Beach Chair/Sitting/Lawn Chair

Question 17

Any position in which the torso is elevated from the supine position & is higher than the legs

Answer 17

Beach Chair

Question 18

What are the advantages of the Beach Chair position?

Answer 18

1. Has less effect on lung volumes
2. Improved ventilation
3. Reduced airway/facial edema
4. Decreased blood loss
5. Excellent surgical exposure

Question 19

What are the disadvantages associated with Beach Chair Position?

Answer 19

1. VAE, Pneumocephalus, quadriplegia, peripheral nerve injuries
2. Blood pools in the lower extremities, leading to decreased BP and decreased venous return
3. Hypotension and bradycardia due to activation of the Bezold-Jarish Reflex (rare) !! may occur in sitting position w/interscalene block

Question 20

What are the positioning implications for a neurosurgery with head pins in place?

Answer 20

1. Face free from pressure (eyes free from pressure)
2. Neck & head neutral (straps secured around forehead & chin)
3. Arm supported by arm rest, padded, secured
4. Hips and knees bent padded, secured
5. ETT taped/secured due to potential for accidental extubation

Question 21

How does ventilation change with awake vs GA in the lateral decubitus position?

Answer 21

-Awake/SV: ventilation favored in dependent lung
-GA w/ PPV: ventilation favored in nondependent lung

Question 22

Position used for surgeries involving the thorax, kidneys, and orthopedics.
-Potential for rhabdomyolysis

Answer 22

Lateral Decubitus

Question 23

How do you position a patient in Lateral Decubitus in the OR?

Answer 23

1. Supine position for induction and airway management, then positioned laterally
2. CRNA in control of head/neck maintaining neutral position
3. Non-operative side down with A/P support (bean bag, jelly rolls, posts, stacked blankets, tape)
4. Verify ETT position, IV patency
5. Monitor NIBP in nondependent arm, SpO2 & ABP on dependent arm

Question 24

What are factors that contribute to the potential for rhabdomyolysis in the lateral decubitus position?

Answer 24

1. prolonged operative time
2. hypotension
3. pressure of OR table on muscles

Question 25

What are some factors to consider when positioning a patient in the Lateral Decubitus position?

Answer 25

1. Maintain neutral head, neck, spine, shoulders, hips
2. Head supported on donut, pillows
3. Ensure ear is flat against head, no pressure to eye
4. Axillary roll to prevent dependent arm/thorax putting pressure on plexus & artery….hand length away from axilla

Question 26

A position that offers improved surgical exposure for gynecological procedures.
-Exacerbates the deleterious ventilatory effects of other positions secondary to a cephalad shift of diaphragm & Abd contents (decreased FRC & TLC)

Answer 26

Trendelenburg (Head Down)

Question 27

What are some physiologic alterations associated with the Trendelenburg position?

Answer 27

1. Increased venous return/CVP/ICP/IOP (edema to face, tongue, airway, eyes)
2. Potential difficult oxygenation/ventilation (increased PIP, decreased lung compliance, decreased tidal volume)

Question 28

Shoulder braces have the potential for ______ injury, ensure arms are secured at side.
-Safety straps prevent falls, slipping and table tipping

Answer 28

Brachial Plexus

Question 29

-Used with Laparoscopy (cholecystectomy)
-Head is higher than the heart → decreased perfusion to brain, decreased ICP/MAP/venous return
-Patient may slip off OR table → consider use of footboard or gel padding, ensure safety straps are not too tight (neuropathies, pressure ulcers)

Answer 29

Reverse Trendelenburg

Question 30

-Pins placed into the skull by the surgeon after induction for fixed head position (very stimulating!)
-Face is free, no pressure points
-Head is fixed to OR table – risk for spinal injury with movement
-Reinforce/secure ETT secondary to significant risk for dislodgement

Answer 30

Mayfield Pins (attached to bed) or Gardner-Wells tongs

Question 31

Why is Cardiac Output & Blood Pressure decreased under general anesthesia?

Answer 31

1. Myocardial depression & vasodilation
2. Blood pooling in dependent body areas
3. Compensatory mechanisms blunted
4. Susceptible to gravitational forces

Question 32

Hemodynamic changes are minimal in which positions?

Answer 32

1. Supine
2. Lateral

Question 33

CO & BP are decreased in which positions?

Answer 33

1. Sitting
2. Prone
3. Flexed Lateral

Question 34

BP may be elevated or normal in ______ due to autotransfusion or central distribution of blood volume.

Answer 34

Lithotomy

Question 35

MAP increases or decreases by about ___ mmHg per ___ inch for each change in height from the heart. There is a risk of hypoperfusion in the head-up or sitting position, Hemodynamic changes minimal in 45 degree position, CO decreases by 20% in 90 degree position.

Answer 35

2 mmHg per 1 inch change

Question 36

Which positions may increase venous pressure in the head?
-Risk for facial swelling & POVL, Position head level/slightly elevated compared to heart
-Potential for unrecognized hypovolemia

Answer 36

1. Prone
2. Trendelenburg

Question 37

True/False: it’s ok to remove monitors while repositioning the patient

Answer 37

False: Standard of Care = monitoring ALWAYS performed during positioning

Question 38

Check NIBP how often during induction & positioning due to often labile BP during these times?

Answer 38

Check NIBP q 1-3 minutes

Question 39

When the patient is prone, positioning the head ____ or ____ than the heart to minimize venous outflow obstruction may prevent the development of _____.

Answer 39

Level or higher; facial edema.