Perioperative Positioning Flashcards
Standard 8
Patient positioning - collaborate with the surgical/procedure team to position, assess, and monitor proper body alignment
Use protective measures to maintain perfusion and protect pressure points/nerve plexus
What is the most common nerve injury
Ulnar and brachial plexus nerve
What are the seven positioning goals
- Safety
- Optimize surgical exposure
- Preserve patient dignity
- Maintain hemodynamics stability
- Maintain cardio respiratory function
- No ischemia, injury, or compression
- Prevent pressure ulcers
How do volatile agents effect CO/BP
Decrease
How do NMBs affect the cardiac system?
Decreased muscle tone = decreased venous return
What is the concern for anatomy cephalad to heart
Risk for hypoperfusion/ischemia
How does gravity effect the pulmonary system
Ventilation - non dependent = dead space
Perfusion - dependent = shunt
Loss of HPV?
What are the ways in which nerves can be injured
Compression, transaction, stretch, traction
Risk factors for pressure ulcers
Elderly, diabetes, PVD, surgical time, chronic hypotension, increased body temp (?), body habitus
Supine positioning mechanics
Lying on back
Arms - secured with arm boards, padding, straps, laterally or abducted (<90 degrees with supinated forearm)
Legs - flat, uncrossed, heel padding
Consider lumbar support
Supine arm positioning/nerve concerns
Avoid brachial plexus injury by keeping arms abducted <90
Avoid ulnar nerve compression by padding elbows and avoiding pronation
(Brachial nerve compression/stretch at shoulder/axial level and ulnar nerve compression at AC/elbow level)
How does the supine position effect the respiratory system
Reduced TLC and FRC
Diaphragm shifts cephalad
General anesthesia and NMBs enhance respiratory effects
Prone mechanics
Head/neck = neutral
Often intubated
Arms abducted but <90
Body/trunk support to keep abdomen from being compressed
How to facilitate proning in OR
Intubate and get lines and everything on the stretcher
Flip on anesthesia’s count - and anesthesia maintains airway
Before anything else - ensure that you still have your airway
Make sure you have enough help and that everyone is sharing the same “mental model”
What types of surgery would you use prone for
Spine, butt, rectum, ankle, intracranial, etc
CV considerations of prone positioning
Pooling of blood in dependent extremities
Compression of inferior vena cava
Epidural engorgement
Respiratory considerations of prone positioning
Decreased compliance if chest/abdomen not freely hanging
Increased FRC
-improved posterior lung ventilation may increase oxygenation
Post op vision loss causes
Prolonged prone position Central retinal artery occlusion Central retinal vein occlusion Ischemic optic neuropathy (89% cause) Cortical blindness
Ways to prevent POVL
Surgical duration <6h 10-15 degree head up (to reduce orbital edema) Bp 20% of preop baseline and MAP > 70 Maintain Hct >25 Avoid prolonged targeted hypotension Avoid head and neck flexion Avoid direct pressure on the eye
Ischemic optic neuropathy
Most common type of POVL
Associated with extended surgical time and extensive blood loss
Not associated with globe pressure
RF = obseity, male, Wilson frame (blood pools in the face because it is dependent d/t frame)
Equation for ocular perfusion pressure
OPP = MAP-IOP
Central retinal artery occlusion clinical signs and symptoms
Sudden, profound vision loss
Painless
Monocular
Etiology of CRAO
“Eye stroke”
Embolism, vasculitis, vasospasm, sickle cell, trauma, glaucoma
Diagnosis of CRAO
Retinal pallor, macular cherry red spot, +/- afferent pupillary defect
Treatment of CRAO
Consult optho and neuro
Case reports of intra-arterial TPA
Limited evidence for treatment - possibly digital massage and lowering IOP
Central retinal vein occlusion “eye dvt” signs and symptoms
Variable - blurred vision to sudden vision loss
Painless
Monocular
CRVO etiology/ risk factors
“Eye dvt” Typical stroke risk factors Hypercoagulable states Glaucoma Compression of vein in thyroid or orbital tumors
Diagnosis of CRVO
Optic disk edema
Diffuse retinal hemorrhages “blood and thunder”
Treatment of CRVO
Consult optho and neuro
No specific treatment
Nerve Compression
Force nerve against bony prominence or some other hard surface (can be a surgical surface like the OR table or positioning tools)
Nerve Transection
Nerve is cut
Stretched nerve
Nerves are pulled tightly
Nerve traction
Nerve stretched over or under something that is immovable
Nerve sheath ischemia direct vs indirect
Direct - d/t something like compression of the nerve itself
Indirect - compartment syndrome
Lithotomy mechanics
Legs abducted and elevated Keep fingers free of footboard Keep legs free to save peroneal nerve Hip flexed Facilitates access to perineum/gyn/urology
***ensure adequate padding
Nerve considerations for lithotomy
Peroneal nerve injury d/t stirrups
Sciatic obturator stretch and femoral nerve palsy d/t hip flexion
Respiratory considerations of lithotomy
20% reduced FRC
Reduced vital capacity
Hypoventilation if breathing spontaneously
Cv considerations of lithotomy
Increased (shifted) central blood volume
Auto Transfusion of 250-300ml/leg when raised
Mechanics of lateral positioning
Head and neck neutral and supported
Shoulders, hips, head, legs aligned in same plane
Eyes, ears, and face should be pressure free
Chest and hip supports
Dependent arm on padded arm board - perpendicular to torso <90
Non dependent arm should be supported - flexion at elbow, padded, secured
Axillary roll should be in use under dependent side of thorax
There should be knew flexion with pillows between knees
REGULARLY assess perfusion
Jack-knife position
Lateral position with the use of a kidney rest
lateral positioning used for
Kidney, shoulder, orthopedic (THA/hip), thorax surgeries
CV considerations of the lateral position
Minimal changes (euvolemic)
Kidney rest elevated may compress great vessels and decrease venous return
How to place kidney rest
Slowly under iliac crest
Resp considerations of lateral position
V/Q mismatch possible
In anesthetized patients:
- FRC is increased in non dependent lung and decreased in dependent lung because diaphragm relaxes and rises to compress dependent lung
In awake patients:
- you have enhanced VQ matching and you do not get the compression of diaphragm
Dependent lung lower than left atrium so its prone to atelectasis and fluid accumulation
Sitting position used for
Cerivical spine surgery, shoulder surgery, posterior fossa, breast reconstruction
Sitting mechanics
HOB 30-90 degrees OR table flexed and backrest elevated Head secured Pad heels and flex legs Secure arms
Dislodge head from headrest with vigorous surgical manipulation is possible so be careful
How do you prevent sciatic stretch in the sitting position
Pad heels and flex legs
Potential complication of Sitting position
VAE
Pneumocephalus
Quadriplegia
Pneumocephalus and the sitting position
Associated with Neuro procedures, often benign
Air enters open dura, CSF drainage, surgical decompression
Quadriplegia and sitting position
Spinal cord stretch when head is flexed combined with loss of auto regulation associated with general anesthesia
Ensure 2 fingerbreadths to limit strain at C5 vertebrae
Cv effects of sitting position
Reduced SV and CO (up to 20%)
Decreased MAP and CVP
Lower extremity venous pooling
Decreased CPP
Respiratory considerations of sitting position
Increased FRC and compliance
Rise in cm to drop in MAP conversion
Every 1 cm rise = 0.75mmHg drop in MAP
So
A map of 65 degrees on an arm BP cuff at level of heart correlates to a MAP of 50 in the brain (if your head is 20cm away from the level of the cuff)
Trendelenburg
Patient is lying in one plane with the head down
Shoulder braces with trendelenburg can cause
Plexus nerve stretch and compression
Stretch if placed to laterally
Compression if placed too medically
Avoid shoulder pads if possible
Pressure changes with trendelenburg
Patient will have increased ICP, IOP, and CVP
Hemodynamics and T-burg
Degree of T-burg = degree of dependent edema and therefore hemodynamic impact
Reverse t-burg
Body is in same plane, bed flat, head up
Physiologic considerations of reverse T-burg
Increased pulmonary compliance and FRC
Decreased ICP, IOP, CPP, BP
Brachial plexus considerations in supine
Make sure arms are abducted less than 90 and make sure humeral head is not rotated
Signs of brachial plexus injury
Weakness in the arms, decreased reflexes and corresponding sensory deficits
Lateral decubitus considerations for brachial plexus injuries
Can cause stretch, traction, tension
And dependent compression via chest
Res Ipsa Loquitor
The thing speaks for itself
Provider presumed negligent if cause of injury is under providers control and issue would not occur without negligence
Stay vigilant
