Positioning For Anesthesia And Surgery

Front 1

Goals of Positioning

Back 1

Maximum exposure to the surgical area while preventing injury
Access to the patient for assessment, maintenance of ventilation, infusion of drugs, and appropriate monitoring.
Patient achieves satisfactory surgical outcome without injury

Front 2

Causes of Position Related Injury

Back 2

Pressure applied over body surface for period of time
Nerve damage from compression, traction, stretch, angulation, or kinking

Front 3

Position-Related Factors

Back 3

Positioning Devices
Length of Procedure
Anesthetic Technique
Surgical Procedures

Front 4

Positioning Devices

Back 4

Straps used to restrain patient
Lateral femoral cutaneous nerve
Crutch or “Candy-Cane” stirrups
Common peroneal nerve
Shoulder braces w/ steep Trendelenberg (head down)
Brachial Plexus injury
Blood Pressure cuff/tourniquet
Radial nerve
Improperly placed axillary roll
Compartment syndrome

Front 5

Length of Procedure

Back 5

Surgery longer than 4-5 hours is usually associated with higher incidence of nerve injuries.

Nerve injury that occurs in short cases is usually due to stretch, compression, or traction

Front 6

Anesthetic Technique

Back 6

Nerve injury occurs more commonly with general anesthesia
Patient cannot move in response to painful stimuli
Paralytics increase mobility of joints

Front 7

Surgical Procedures

Back 7

Cardiac procedures with median sternotomy
Ulnar and brachial plexus injuries
Vaginal hysterectomy
Femoral and lumbar plexus injuries

Front 8

Supine

Back 8

Head neutral on small pillow (doughnut)
Avoid brachial plexus injury
Pt. legs uncrossed without pillow!
Avoid superficial peroneal nerve damage
Arms padded, less that 90 degrees, supinated.
Avoid ulnar nerve damage

Front 9

Supine cont.

Back 9

Cardiac output and BP transiently increase
General anesthesia attenuates normal baroreceptor response

FRC and TLC reduced/cephalad shift of diaphragm

Front 10

Prone- face down

Back 10

Supine for induction and intubation
Optimal exposure for spinal or back surgery
Reduces incidence of VAE when used with posterior fossa surgery
Body is supported with chest frames (or rolls), leg pillows, upper extremities secured to armboard
Pad all pressure points at elbow, knee, ankles, genitalia(man), limit pressure on breasts.

Front 11

Prone cont.

Back 11

Anesthetist responsible for maintaining head alignment during turn
Protect patient eyes – blindness can occur if central retinal artery is occluded.
Foam cushion, pillow, 3 point skull fixation, Mayfield headrest, etc
Arms should be carefully rotated into position.

Front 12

Hemodynamic changes in Prone

Back 12

Cardiac output is decreased in prone position.
Other hemodynamic variables do not change significantly.
Avoid pressure over abdomen that impedes venous return

Front 13

Prone- Ventilation is affected by?

Back 13

limited anterior chest expansion
Diaphragmatic excursion can be limited by the abdominal viscera
FRC decreased (?) compared to sitting position, but not as much as supine pt
Oxygenation improved despite decrease in FRC

Front 14

Prone Complications

Back 14

Eye injury – corneal abrasion, visual loss
Macroglossia – seen with extreme flexion head, do not use oral airway!
Neurologic injuries – brachial plexus
VAE, not as common as sitting position

Front 15

Lithotomy

Back 15

Used for surgery requiring access to perineal structure.
Arms are positioned similarly to supine
Watch fingers to avoid crush if “tucked”
Legs are flexed and abducted above torso
Low, standard, high, or exaggerated

Front 16

Hemodynamic changes in lithotomy

Back 16

Central blood volume is increased after auto transfusion from raising legs
CVP, PAP, & PCWP all increase when trendelenberg added
Reduction in pressure can cause hypoperfusion & ischemia in pt with PVD
Use leg holders with foot support & low lithotomy
Hypovolemia may not be recognized

Front 17

Respiratory changes with lithotomy

Back 17

Obese, and GETA have decreased V/Q Ventilatory changes similar to supine
FRC not further reduced
Diaphragm doesn’t shift further cephalad
Concomitant use of Trendelenburg can cause decrease in FRC
Awake, breathing patients V/Q unchanged

Front 18

Precautions with lithotomy

Back 18

Both legs should be moved at same time to avoid hip dislocation, back/hip pain
Avoid abduction & external rotation of leg
Can cause femoral nerve or lumbosacral plexus stretch injury
Avoid extreme flexion of hip or knee
Causes compression femoral/popliteal neurovascular structures
Carefully pad point of contact on outer leg
Peroneal nerve superficial course makes very susceptible to injury

Front 19

Lateral Decubitus

Back 19

Supine for induction and intubation
Used for kidney and thoracic surgeries if inadequate exposure w/ supine position
Use kidney rest for nephrectomy
Can be used for craniotomy
Orthopedic surgery of hip and shoulder

Front 20

Lateral Decubitus cont.

Back 20

Shoulders, hips, head, and legs in alignment for turn.
Head & neck neutral on pillow, doughnut
Dependant ear and eye free of pressure
Pad all bony prominences

Front 21

Lateral Decubitus cont. #2

Back 21

“Bean-bag” used to stabilize patient

Dependant arm padded, less than 90, non-dependant out of surgical field

Axillary roll used to decompress shoulder neurovascular structures
always document
less than 90 degrees

Front 22

CV and Resp. changes with lateral decubitus?

Back 22

Minimal CV changes
FRC decreased in dependent lung, and increased in nondependent lung
V/Q greater in dependent lung in awake patient, but decreased after induction
In nondependent lung ventilation is greater and compliance increased
Perfusion greater in dependent lung in awake or spontaneous ventilation

Positive pressure abolishes gravitational effect in anesthetized patient

V/Q mismatches in 1 lung ventilation

Front 23

Injuries associated with lateral decubitus?

Back 23

Ulnar nerve most commonly injured due to pressure on cubital tunnel
Common peroneal most common injured in lower extremity
Brachial plexus injury caused by arm abduction more than 90 degrees
Damage to dependent eye can occur if not protected

Front 24

Sitting

Back 24

Elevation of head may vary

Lounge, lawn, or beach chair
Hypotension is frequent

Minimized if only 45 degrees vs 90

Less effect on lung volume than other positions

Front 25

Complications with the sitting position

Back 25

VAE is the most feared complication
Air enters venous system because of negative pressure gradient between RA and veins at the operative site
Incidence unknown and complications proportionate to amount air entering

Front 26

Trendelenberg

Back 26

Any position where head is lower than rest of body
Used outside OR for treatment of hypotension
Variable effect on blood pressure
Hypotensive patients show no increase in MAP, increase SVR, and decreased CI.
Normotensive patients compensate for increased CVP with vasodilation and decreased HR

Front 27

CV changes with Trenddelenberg

Back 27

Hypovolemia may go unrecognized

Remember additive effect with lithotomy

Increased venous pressure in face may cause orbital, pharyngeal & facial edema

Front 28

Resp. changes with Trendelenberg?

Back 28

FRC is decreased proportionally with degree of trendelenberg

Mediastinal shift cephalad can cause mainstem intubation

Risk for aspiration?

Front 29

Injuries associated with Trendelenberg?

Back 29

Arms are vulnerable to injury if placed on arm boards.
Tendency to slip off, hyperextend, and abduct above head and stretch brachial plexus