Intraoperative Positioning

Question 1

Nerve Injury (overall)

Answer 1

result in temporary or permanent sensory or motor deficits, paresthesias, or pain, and in some cases, these injuries are related to patient positioning.

The incidence of perioperative nerve injury unrelated to surgery of 0.03 percent
Nerve injury accounts for 12 percent of malpractice injury
patients

Patients who are awake or lightly sedated without regional anesthesia should be at lower risk

Question 2

Mechanism of perioperative Nerve Injury

Answer 2

Not well understood: likely due topositioning (compression and stretch), ischemia, and/or inflammation.

Question 3

High Risk Nerves

Answer 3

Due to position related injury or stretching (brachial plexus with neck rotated)

Superficial nerves like peroneal at the fibular head and ulnar nerve at the ulnar groove of the elbow

Question 4

Risk Factors of Nerve Injury

Answer 4

longer surgical procedures

extremes of body weight

older age

smoking

hypertension

diabetes

Question 5

Prevention of Nerve Injury (Preoperative Assessment)

Answer 5

Preoperative assessment- Risk factors addressed and patients ability to tolerate certain positions

Question 6

Prevention of Nerve Injury (brachial plexus)

Answer 6

Brachial Plexus-
Supine: arm abduction should be <90 degrees.
Prone: Abduction >90 MAY be tolerated

Question 7

Prevention of Nerve Injury (Ulnar Nerve)

Answer 7

Ulnar Nerve-
Arms abducted- avoid pressure on ulnar groove, forearm supinated or neutral
Arms tucked- forearm should be neutral

Question 8

Prevention of Nerve Injury (Radial Nerve)

Answer 8

Radial nerve- avoid pressure on the nerve in spiral groove of humerus

Question 9

Prevention of Nerve Injury (Median Nerve)

Answer 9

Median Nerve- Avoid extension of elbow beyond preoperative comfortable range

Question 10

Prevention of Nerve Injury (Sciatic Nerve)

Answer 10

Avoid stretch of hamstring. muscle group beyond preoperative comfortable range

Consider extension and flexion of BOTH hip and knee joints, as nerve crosses both joints

Question 11

Prevention of Nerve Injury ( Femoral Nerve)

Answer 11

When possible avoid extension or flexion of the hip

Question 12

Prevention of Nerve Injury (Perineal Nerve)

Answer 12

Avoid pressure on nerve at fibular head

Question 13

Prevention of Nerve Injury (Protective Padding)

Answer 13

Arm boards should be padded

use chest roll in lateral decubitus position

Pad at the elbow

Question 14

Skin and Tissue Injury (Risk Factors)

Answer 14

Low Braden Scale Score

Extremes of BMI

Older age

Total Surgery time

Hypotension

Vasopressor

High ASA Score

Fun Fact: Immobilization places patients at risk for skin and underlying tissue injury during anesthesia, particularly during longer surgical procedures.
The incidence of skin and tissue injuries during hospitalizations is 10 to 37%

Question 15

Operating Tables

Answer 15

movement of OR table with patient on it should be AVOIDED

If you have to move the patient make sure patient is secured

Remember OR tables have weight limits: Weight limits change as table is tilted side to side or top to bottom*

Weight limits are also changed if patient is in reverse orientation

Question 16

Supine Position

Answer 16

(or dorsal decubitus) position, one or both arms may be abducted out to the side on arm boards or tucked next to the patient’s body- this can cause stretching to the brachial plexus

Arms should be abducted less than 90 degrees, to avoid stretching the brachial plexus across the head of the humerus in the axilla***

Question 17

Physiologic effects of Supine Position (Cardiac)

Answer 17

Cardiac- Minimal

Advanced stages of pregnancy or patients with large abdominal masses are at risk for aortocaval compression and hypotension in the supine position and may benefit from leftward tilt with a wedge under the right hip.

Question 18

Physiologic Effects of Supine Position (Pulmonary)

Answer 18

primarily related to cephalad displacement of the diaphragm by abdominal contents.

Changing body position from upright to supine reduces functional residual capacity by 0.8 to 1 L (ie, from approximately 3.5 L to 2.5 L) and induction of anesthesia causes another decrease by 0.4 to 0.5 L

Question 19

Nerve Injuries With Supine Position

Answer 19

-Ulnar nerve- arms are abducted, forearm should be supinated or in a neutral arm position

arms are adducted along the patient’s side, the forearms are usually placed in a neutral position, with the palm facing the patient

• Radial nerve- Risk for compression where the radial nerve runs in the spiral groove of the humerus in the posterior upper arm.
• Arm board padding should be even with the operating table mattress, without a step that could compress the nerve
• IV poles and devices attached to the operating table should be positioned away from the patient’s upper arm.
• Brachial plexus- Injuries are usually to the lower roots of the brachial plexus due to stretching

Question 20

Concerns with Supine Position

Answer 20

Pressure Points- Occiput (alopecia), heels and sacrum
Head should be supported with gel doughnut and intermittently turned

Backache- Pillow placed under knees

Extreme Head and Neck Extension:
- flex to chin DECREASES distance b/w ETT and carina
- extension INCREASES distance b/w ETT and carina
“tube goes where the nose goes”

Question 21

Trendeleburg Position

Answer 21

Supine position with the head of the operating table tilted down.

Improves exposure of pelvic organs during abdominal and laparoscopic surgery and may be used briefly to facilitate central line placement.

Supportive equipment- slip-resistant table padding, cross chest taping, kneee flexion, bean bag supports and shoulder supports.

Question 22

Concerns with Trendelenburg

Answer 22

NERVE INJURIES:

Similar to supine position

Brachial Plexus injury due to compression: shoulder supports are placed at the base of the neck

Supports should be placed LATERALLY at acromioclavicular joint to avoid nerve compression*

AIRWAY INJURIES:

Airway, facial, tongue and laryngeal tissue edema- be mindful upon extubation*

Question 23

Physiologic Effects of Trendelenburg Position

Answer 23

Cardiac- Increased venous return, Increased right & left sided cardiac filling pressure, increase PAP and MAP- CAREFUL with HF patients

Abdomen- Abdominal contents shifted up (cephalic) = atelectasis and DECREASED FRC and DECREASED lung compliance, V/Q mismatching. INCREASED risk for aspiration- hesitant to use LMA

Neuro- Increase ICP, AVOID WITH TBI

Facial Edema- CAUTIOUS OF AIRWAY SWELLING- assess patient’s eyes

Question 24

Reverse Trendelenburg

Answer 24

Supine positioning with the head of the operating table tilted up.

Used for upper abdominal surgery

Padded foot board may be required

Question 25

Physiologic changes in the reverse Trendelenburg position

Answer 25

Cardiac- DECREASED venous return, decreased cardiac output, preload, MAP. Compensatory mechanisms= tachycardia, increased sympathetic tone and PVR Pulmonary-lung volumes and FRC are INCREASED Neuro- CPP decreases with head above heart. Measurement of blood pressure at the level of the Circle of Willis gives a more accurate representation of cerebral perfusion than measurement at the level of the upper arm. Arm cuff measurements should be adjusted to account for the gradient in hydrostatic pressure. Nerve injuries- similar to supine injuries

Question 26

Lithotomy Position

Answer 26

The lithotomy position is a supine position, with the legs separated and hips and knees flexed to a variable degree. Used for urological, gynecological and some rectal procedures Lower extremities are flexed at BOTH hip and knees. HIGH lithotomy hips are flexed at 90 degree angle Arms may be abducted on padded boards or tucked to side

Question 27

Physiologic changes in the lithotomy position

Answer 27

Cardiac- venous return is INCREASED (may be minor transient affect) Pulmonary- The diaphragm may be displaced cephalad by abdominal contents, resulting in a DECREASED in functional residual capacity and lung compliance and increases in inspiratory pressures

Question 28

Nerve injuries associated with lithotomy position

Answer 28

**Peroneal Nerve**- at risk for compression at the fibular head= lateral lower leg should be free or padded when stirrups are used **Saphenous nerve**- can be compressed by contact with the leg brace medially as it courses superficially and horizontally across the medial femoral epicondyle. This bony prominence should be padded. **Lateral femoral cutaneous and obturator nerves**- may be associated with hip flexion beyond 90 degrees **Sciatic Nerve-** Can be stretched at the level of the hip or knee

Question 28

Nerve injuries associated with lithotomy position

Answer 28

Peroneal Nerve- at risk for compression at the fibular head= lateral lower leg should be free or padded when stirrups are used Saphenous nerve- can be compressed by contact with the leg brace medially as it courses superficially and horizontally across the medial femoral epicondyle. This bony prominence should be padded. Lateral femoral cutaneous and obturator nerves- may be associated with hip flexion beyond 90 degrees Sciatic Nerve- Can be stretched at the level of the hip or knee

Question 29

Concerns with lithotomy position

Answer 29

Coordinated positioning-The patient's legs should be SIMULTANEOUSLY placed in leg supports or stirrups by two attendants, to avoid torsion of the lumbar spine and extension of the hip joint. Take them out in same manner. Hand injury- If the arms are adducted, the hands and fingers may be at risk for injury when the foot section of the OR table is moved; AMPUTATION OF FINGERS\*\* has been reported. Back pain- The lithotomy position may aggravate radicular pain in patients with a preexisting herniated lumbar disk.

Question 30

Lateral decubitus

Answer 30

-The lateral decubitus position may be used for surgery on the thorax, retroperitoneal structures, or hip. -Patient lies with the operative side up, with anterior and posterior supports (eg, blanket or gel rolls, or a bean bag support) to prevent rolling to the supine or prone position during surgery. The legs are slightly flexed, with pillows or foam padding between them. - The left lateral decubitus position would mean that the patient is lying on his or her left side - A pad or roll is placed under the chest wall, to alleviate pressure on the neurovascular structures in the axilla. The down arm is padded, and the up arm is supported on pillows or any number of arm supports

Question 30

Lateral decubitus

Answer 30

-The lateral decubitus position may be used for surgery on the thorax, retroperitoneal structures, or hip. -Patient lies with the operative side up, with anterior and posterior supports (eg, blanket or gel rolls, or a bean bag support) to prevent rolling to the supine or prone position during surgery. The legs are slightly flexed, with pillows or foam padding between them. - The left lateral decubitus position would mean that the patient is lying on his or her left side - A pad or roll is placed under the chest wall, to alleviate pressure on the neurovascular structures in the axilla. The down arm is padded, and the up arm is supported on pillows or any number of arm supports

Question 31

Physiologic effects of lateral decubitus positioning

Answer 31

Cardiac- blood pools in lower extremities= DECREASED venous return and hypotension. Inferior vena cava can be partial or completely obstructed by marked flexion of the hips Pulmonary- perfusion of the dependent lung usually increases, while ventilation of the dependent lung decreases, due to reduced functional residual capacity and compliance. At the same time, ventilation increases and perfusion decreases in the nondependent lung. V/Q mismatch leads to hypoxia and a high fraction of inspired oxygen may be required

Question 32

Nerve injuries associated with the lateral decubitus position

Answer 32

Brachial Plexus- if chest roll is not properly placed. Roll is called an axilla roll but should NOT be placed directly under axilla Roll should be placed caudal to the axilla, to free the axillary structures from compression Avoid neck flexion-support in neutral position Dependent arm (straight arm on table)- placed on padded arm board and abducted no more than 90 degree -Upper portion of the nondependent arm should be parallel to dependent arm and supported by blankets and pillows.

Question 33

Prone Position

Answer 33

- Used for spine procedures, some craniotomies, rectal and buttock procedures, superficial procedures on the back, and surgery on the posterior extremities. - Patients are anesthetized first then rolled prone after intubation - Head should be supported on foam or gel head rest. - Torso supported by surgical frame, chest rolls or pillows

Question 34

Prone Position

Answer 34

- sometimes patients can prone themselves and head is usually turned to side on pillow Example- MAC cases - Arms placed in "superman" position- shoulder and elbows flexed - make sure they do not have shoulder injuries prior to doing this

Question 35

Physiologic effects of prone positioning

Answer 35

**Cardiac**- Reduced cardiac index, DECREASED venous return and reduced left ventricular compliance due to increased intrathoracic pressure **Pulmonary**- Beneficial pulmonary function **POSTOPERATIVE VISION LOSS\***- Face below the level of the heart causes ischemia, congestion and edema

Question 36

Nerve injuries associated with the prone position

Answer 36

- Do not overextend arms and avoid stretching or compressing neuromuscular bundles in axilla - Test ROM to shoulder prior - Make sure chest rolls do not compress axilla

Question 37

Long slide on Turning Prone

Answer 37

Please review, too wordy for flash card \<3

Question 38

Concerns with prone position

Answer 38

- Neck position: Neck should be neutral without excessive flexion or extension relative to the torso, or in the natural position for patients with neck deformities. - This may require changing the height of the torso or head support, adding or removing padding under the face pillow, or changing the height or angle of the Mayfield apparatus. Protecting the face The head is supported on the bony prominences of the face (ie, the forehead and the chin). The eyes, nose and endotracheal tube should be checked after positioning and repeatedly during surgery to make sure there is no pressure or traction on the eyes or other facial tissues and that the endotracheal tube remains securely in place. document\* Protecting the eyes Confirm proper occlusion of eyes to prevent the introduction of cleaning solutions

Question 39

Sitting Position (Beach Chair)

Answer 39

- Usually done for shoulder procedures - try and avoid AC lines

Question 40

Physiologic effects of the sitting position

Answer 40

Cardiac- Venous pooling in lower extremities, vasodilation and myocardial depression. DECREASE in preload, stroke volume, MAP and CPP- Blood pressure below 80% of preoperative resting values NEED to be treated\* Pulmonary - FRC and lung compliance INCREASE NEUROLOGIC\*\*- CPP will DECREASE when head is raised about the heart MAINTAIN O2 AND CPP -Every 1 cm difference between the cuff and the auditory meatus, MAP would be 0.77 mmHg lower at the brain than measured by the cuff (ie, 1 mmHg for every 1.25 cm). Example: Patient in beach position with the external auditory meatus 30 cm above the midpoint of the blood pressure cuff, MAP at the brain would be unacceptably low, at approximately 47 mmHg, with a MAP of 70 mmHg as measured by the cuff. Basically: (30 cm X 0.77) = 23.1 70-23.1= 46.9 mmHg

Question 41

Concerns with sitting position

Answer 41

- Neck flexion can cause vascular obstruction, kinking of ETT or SAD, tongue and oropharyngeal swelling - Maintain two finger breaths of space between mandible and sternum \*Sitting craniotomy= INCREASED RISK FOR VENOUS AIR EMBOLISM AND SUPRATENTORIAL PNEUMOCEPHALUS\*

Question 41

Concerns with sitting position

Answer 41

- Neck flexion can cause vascular obstruction, kinking of ETT or SAD, tongue and oropharyngeal swelling - Maintain two finger breaths of space between mandible and sternum \*Sitting craniotomy= INCREASED RISK FOR VENOUS AIR EMBOLISM AND SUPRATENTORIAL PNEUMOCEPHALUS\*

Question 42

Turned Patients

Answer 42

- Turned patients at 90 or 180 degrees - Will limit airway access - Extension tubing may be needed for the airway circuit and the intravenous lines. - shoulder or ENT cases- less likely for MAC - if turned 90 degrees ideally the IV is in extremity closest to anesthesia