Surgical Positioning

Surgical PositioningSurgical PositioningJeffrey Groom PhD, CRNA

Nurse Anesthetist ProgramFlorida International University

SURGICAL POSITIONING OBJECTIVES

SURGICAL POSITIONING OBJECTIVES

• Identify the role and responsibility of the anesthesia provider in patient positioning.

• Describe the complications associated with improper patient positioning.

• Describe the physiological changes that occur with the various positions.

• Identify scenarios involving medicolegal liability associated with improper patient positioning.

Surgical tableSurgical table

Surgical PositioningSurgical Positioning

SUPINE


Trendelenberg – Reverse Trendelenberg


Lateral Tilt


Lithotomy


Sitting – Beach Chair


JackKnife - Kneeling



Surgical PositioningOR Table Attachments

Surgical PositioningOR Table Attachments


• All positioning schemes have 3 goals:– 1. Maximum exposure to the surgical area

while maintaining homeostasis and preventing injury

– 2. Position must provide the Anesthetist with adequate access to the patient for airway management, ventilation, medications, and monitoring

– 3. Promote the enhancement of a satisfactory surgical result


What happens when the anesthetized patient can’t care for themselves?


When you sleep, you reposition yourself to prevent pressure ischemia. Under anesthesia, the patient does not reposition (protect) them self so the responsibility falls to the surgical team to prevent pressure ischemia & positioning injuries.


• Positioning and Anesthesia– Blunted or obtunded reflexes prevent

patients from repositioning themselves for relief of discomfort

– Anesthesia may blunt compensatory sympathetic nervous system reflexes that would minimize systemic BP changes with abrupt position changes

– Rendering patients unconscious and relaxed may permit placement in position they may not have normally tolerated in an awake state

Why is there a risk for injury ?

Patient Injury and Surgical Positioning Patient Injury and

Surgical Positioning

• Most are nerve injuries due to overstretching and/or compression.

• 90% undergo complete recovery.• 10% are left with residual weakness or sensory loss.• Many injuries can produce lasting disability.• Many injuries lead to litigation.• General anesthesia removes many of the bodies

natural protective mechanisms.• Recognition of risks and prevention is essential.

How do nerves get injured? Example

Nerve fiber

•motor fibers (somatic and autonomic) leave the cord via the ventral roots

•sympathetic fibers leave the cord via ventral roots from T1 - L2

•only sensory fibers run in the dorsal root

Peripheral Nerves from Spinal Cord

Peripheral Nerve InjuryPeripheral Nerve Injury

Preoperative History and Physical Assessment

Preexisting patient attributes associated with increased incidence of perioperative neuropathies:– extremes of age or body weight, – preexisting neurologic symptoms, – diabetes mellitus, – peripheral vascular disease,– alcohol dependency, – smoking, – and arthritis.

Surgical PositioningASA Closed Claims

Surgical PositioningASA Closed Claims

• 1999 - 670 claims for anesthesia-related nerve injuries

• #1 - Ulnar nerve (28%)

• #2 - Brachial plexus (20%)

• #3 - Common peroneal (13%)


Ulnar nerve injury• Caused by arms along side patient in pronation• Ulnar nerve compressed at elbow between table

and medial epicondyle.• Prevented by positioning arms in supination.• Hypotension and hypoperfuison increase risk.

Ulnar NerveUlnar Nerve

Yo s’up dude?Yo s’up dude?


Brachial Plexus Injury• Excessive arm abduction or external rotation.• Prevented by avoiding more than 90o abduction.• Secure arm to prevent arm from falling off of table

or arm board.

Brachial PlexusBrachial Plexus


Brachial Plexus• Abduct arms to no more than 90 degrees.• Minimize simultaneous abduction, external arm rotation,

and opposite lateral head rotation.• In prone position, maintain abduction and anterior flexion

of arms above head to no more than 90 degrees.• In lateral position, place chest roll under lateral thorax to

minimize compression of humerus into axilla.

Brachial PlexusBrachial Plexus


Peroneal nerve

• Caused by direct pressure on the nerve with the legs in lithotomy position.

• Nerve compressed against neck of fibula.

• Prevented by adequate padding of lithotomy poles.



Surgical Positions and Anesthesia ImplicationsSurgical Positions and

Anesthesia Implications


SUPINE

Surgical PositioningSupine


• Most frequently used position.

• Cervical, thoracic, lumbar vertebrae should be in a straight, horizontal line.

• Minimal effects on circulation.

• FRC decreases 25-30% from upright.

• Arm boards and arm must be less than 90o abduction angle to the torso.

Surgical PositioningSupine (con't)

Surgical PositioningSupine (con't)

• Arms at greater than 90o angle results in stretch of the subclavian and axillary vessels resulting in radial pulse obliteration and arterial thrombosis.

• Injuries have been reported with as little as 60o

abduction.• Palms up- relieves pressure on the ulnar nerve

as it passes through the humeral notch at the elbow.



• Ulnar nerve injury

– Hypotension and hypoperfusion increase risk

– Inability to abduct or oppose the 5th finger

– Atrophy of the intrinsic muscles of the hand (claw hand).



• Extreme rotation of the head can cause occlusion and thrombosis of the vertebral artery.

• Pressure from a mask or head strap can cause injuries of the supraorbital and facial nerves.

• Relaxation of the paraspinous muscles and flattening of the normal lumbar convexity results in tension on the interlumbar and lumbosacral ligaments causing a backache.



Surgical PositioningProne



• Induction completed on stretcher, then patient logrolled to OR table under command of CRNA

• Body ‘logrolled’ as a unit in a smooth, slow, and gentle manner.

• Neck in alignment with spinal column.• Eyes and ears protected and not depressed.• Chest rolls, or bolsters are placed lengthwise on

both sides of the thorax, extending from the acromioclavicular joints to iliac crest-adequate lung expansion and diaphragm excursion.



• Protect female breasts & male genitalia.• Pillow under legs & ankles to flex knees

and prevent pressure on toes and plantar flexion of feet.

• Arms at side or extended alongside the head on arm boards

• Documentation: pressure points padded, free abdominal and chest expansion, position of the arms, eye care



• Cardiac– Pooling of blood in extremities- Compression of abdominal muscles - Decrease preload, c.o., and blood pressure- Increased SVR and PVR- Decreased stroke volume and cardiac index- TEDS or pneumatic sequential compression

stockings to minimize pooling of blood



• Respiratory– Decreased lung compliance– Increased work of breathing– Thoracic Outlet Syndrome-secondary to

thoracic nerve compression (agonizing, debilitating, and unremitting pain post-operatively following overhead arm placement

– ETT dislodgement - Extubation


Trendelenberg – Reverse Trendelenberg

Surgical PositioningTrendelenburg

Surgical PositioningTrendelenburg

• Cardiac– Activation of baroreceptors– Decrease in C.O., PVR, HR, and BP– Does not improve C.O. in hypotension & hypovolemia

• Respiratory– Decreased FRC, total lung capacity and pulmonary

compliance secondary to shift of abdominal viscera– Increased V/Q mismatching– Atlectasis– Increased likelihood of regurgitation

• Use of shoulder braces to prevent cephalad mvmt

Surgical PositioningReverse Trendelenburg

Surgical PositioningReverse Trendelenburg

• Cardiac– Decrease in c.o., preload, and arterial

pressure– Baroreflexes increase sympathetic

tone, HR , PVR.• Respiratory

– Work of breathing decreased– Increase in FRC

Surgical PositioningLateral Decubitus




• Usually positioned with bean bag or position supports.

• Head must be aligned to support the spinal column and prevent compression of dependent arm.

• Pillows placed between legs and feet• Bottom leg flexed to provide stability and

facilitate venous drainage.• Peroneal nerve susceptible to injury



• Presents anesthetic challenges- – Compression of vena cava with kidney rest– Dependent lung is underventilated-pressure of

abdominal contents and wt of mediastinum.– Nondependent lung is overventilated because

of increased compliance.– Blood flows to underventilated lung by gravity.– V/Q mismatch may manifest as hypoxemia



• Kidney rest- beneath the bony iliac crest, not under fleshy waist area

• Axillary rolls- placed at scapula near the axillary space to relieve pressure on the arm and foster adequate chest excursion.

• Dependent shoulder, axilla, and deltoid must be padded.• Lower arm brought forward to prevent pressure on

brachial plexus. • Chest surgery- upper arm flexed at elbow and raised

above head to elevate scaplua and widen intercostal spaces.



• Cardiac – Output unchanged unless venous return

obstructed (kidney rest).– May see decrease in arterial blood pressure as a

result of decreased vascular resistance (R > L).

• Respiratory– Decreased volume and increased perfusion of

dependant lung, V/Q mismatch potential


Sitting – Beach Chair

Surgical PositioningSitting


• Cardiac– Pooling blood in lower body decreases central blood

volume.– ABP fall despite increase in HR & SVR. (30%)– C.O. decreases 20-40%– Increase in sympathetic /parasympathetic tone– Intrathoracic blood volume decreases as much as 500 ml

• Respiratory– Lung volumes are increased.– FRC is increased.– Work of breathing is decreased.


• Posterior Foss Craniotomy & shoulder procedures.

• Full sitting position is uncommon.• Lounge chair, beach chair.• Facilitates venous drainage.• Venous air embolism risk is potential hazard



• Complications– Postural hypotension– Air emboli

• Potentially lethal• Chances increase with degree of elevation of op site.• Dx: change in heart rate, murmur, decreased in exp

CO2, cardiac dysrythmias, change in heart sounds generated by a parasternal Dopppler.

• TEE most sensitive for detection (0.015 ml/kg/air)• Gasp breath may be first indicator• Decreased Pa02, etCO2, increased etN



• Complications– Ocular compression– Pneumocephalus– Edema of face, head, and neck due to

prolonged neck flexion resulting in venous and lymphatic obstruction.

– Sciatic nerve injury• Bended knees without flexion of the hips• Foot drop is clinical manifestation


Lithotomy

Surgical PositioningLithotomy

Surgical PositioningLithotomy

• Cephalad displacement of the diaphragm.• Principle hazards:

– Common peroneal- foot drop– Femoral- decreased or absent knee jerk– Saphenous-– Obturator-inability to adduct leg & diminished

sensation over medial side of the thigh– Sciatic nerve- weakness of all skeletal muscles

below the knee• Both legs should be elevated & flexed at same time to

avoid stretching of peripheral nerves• Thighs should be no more than 90o

AANA Scope and Standards for Nurse Anesthesia

PracticeStandard V

AANA Scope and Standards for Nurse Anesthesia

PracticeStandard V

Nurse anesthetists should “monitor and assess patient positioning and protective

measures at frequent intervals.”

Failure to follow professional standards and guidelines may result in

positioning injuries and liability.

Pommier vs Savoy Memorial Hospital55 y.o female w/fractured hip

2hr 20 min surgery

Developed peroneal palsy post-op

LIABILITY EXAMPLES

Protective and monitoring measures were not taken nor documented. No prior injury present. Conclusion at trial – injury would not have occurred had there not been negligence – res ipsa loquitur.

Shahine vs. Louisiana State University Medical Center,

680 So. 2d 1352 (La. App., 1996)• "#6 table with safety strap in place 2" above knees -

supine with bean bag underneath patient post induction & catheter insertion into the left side, with right side up, per __M.D. & __M.D, - auxiliary roll in place (1000cc bag IV fluid wrapped in muslin cover) - held in place per surgeons until bean bag deflated with suction - pillow placed under right leg with left leg bent slightly - U drape in place per surgeons pre prep - left arm extended on padded arm board - right arm placed on mayo tray that is padded."

Protective and monitoring measures were taken and documented. Brachial plexus injury reported postop. No prior injury present. Conclusion at trial – injury was a risk of the procedure however personnel took precautions according to standards and were not negligent.

ASA Practice Advisory – Sets a legal standard of careLINK to Advisory in the Course Outline Page

Upper extremity positioningUpper extremity positioning• Arm abduction should be limited to 90° in supine

patients; patients who are positioned prone may tolerate arm abduction greater than 90°

• Arms should be positioned to decrease pressure on the postcondylar groove of the humerus (ulnar groove).

• When arms are tucked at the side, a neutral forearm position is recommended. When arms are abducted on armboards, either supination or a neutral forearm position is acceptable

• Prolonged pressure on the radial nerve in the spiral groove of the humerus should be avoided

• Extension of the elbow beyond a comfortable range may stretch the median nerve

Lower extremity positioning

• Lithotomy positions that stretch the hamstring muscle group beyond a comfortable range may stretch the sciatic nerve

• Prolonged pressure on the peroneal nerve at the fibular head should be avoided

• Neither extension nor flexion of the hip within normal range of motion increases the risk of femoral neuropathy

Protective padding• Padded armboards may decrease the risk of upper

extremity neuropathy• The use of chest rolls in laterally positioned

patients may decrease the risk of upper extremity neuropathies

• Padding at the elbow and at the fibular head may decrease the risk of upper and lower extremity neuropathies, respectively

Equipment• Properly functioning automated blood pressure

cuffs on the upper arms do not affect the risk of upper extremity neuropathies

• Shoulder braces in steep head-down positions may increase the risk of brachial plexus neuropathies

Postoperative assessment• A simple postoperative assessment of

extremity nerve function may lead to early recognition of peripheral neuropathies

Documentation• Charting specific positioning actions during the

care of patients may result in improvements of care by (1) helping practitioners focus attention on relevant aspects of patient positioning; (2) providing information that continuous improvement processes can use to lead to refinements in patient care; and (3) provide medicolegal defense

Positioning ChecklistPositioning Checklist


Positioning Checklist

1. Head, neck and cervical spine supported in a straight line.

2. Scalp, head, and face protected from tight anesthesia mask/straps.

3. Ears protected from traumatic pressure/objects.4. Chest and torso kept in physiological position for

adequate full, bilateral respiratory exchange and expansion.

5. Breasts & genitalia protected from excessive pressure.

6. Arms in physiological position and supported.- not to exceed 90 degree extension at shoulder- in flexion not hyperextension- upper arm not hanging over edge of table or rubbing on metal part of table- elbow area protected from ulnar pressure- hands free of pressure and compression- fingers in slight flexion or neutral extension- wrist restraints loose or padded- palms up on armboard- palms towards body when arms at side

Positioning Checklist

7. Genitals free of trauma, pressure, or rubbing.8. Back in physiological position, spine in straight line

- slight sacral curvature- soft small positioning devices under sacral area

and knees to relieve pressure, pain, or stretching.9. Thighs/legs in straight line of flexed position; no pressure

to iliac crests, greater trochanters, area bt back & knees, peroneal nerve on lateral aspects of knees, or to patellas.

10.Heels/ankles/toes free of pressure or rubbing trauma.11.Safety belt placed snugly over patient w/blanket or towel

between strap and patient’s body to prevent maceration.12.Other straps or positioning devices placed only over

padded body parts.


During clinical this semester – spend time after cases learning the operation of the OR table and proper positioning. Practice on each other to appreciate “positioning” from patient’s perspective.

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Surgical Positioning

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