Patient Positioning Flashcards
What do you document from patient positioning?
- Pre-op patient limitations in movement strength, nerve abnormalities.
- Numbness, tingling, loss of sensation to any extremity pre-op
- Foot drop
- Head movement limitations
Head-up, sitting, and lithotomy position effect on hemodynamic changes
Regions above the heart at risk for hypoperfusion and ischemia (esp if hypotensive), COP decreased 20%
Prone and lateral position effect on respiratory system
Redistribute ventilation and perfusion the most in these positions
Lateral decubitus position effect on respiratory system
- Abdominal contents shift cephalad
- Anesthetized patient: Dependent lung (down) underventilated but gravity favors blood flow there. Nondependent lung (up) is over ventilated
- Awake patient: Dependent lung has increased ventilation and blood flow
Prone position effect on respiratory system
Decreased diaphragmatic excursion, abdomen hangs free
Lithotomy and Trendelenburg position effect on respiratory system
- Abdominal viscera shifted cephalad
- TLC, VC, and FRC all decreased
Steep Trendelenburg position effect on respiratory system
- ETT migrates to right mainstem bronchus (recheck breath sounds after position change)
- Increased pulmonary venous pressure
- Decreased pulmonary compliance, FRC (d/t increased central venous pressure from abdominal contents shifting cephalad against diaphragm)
How to prevent V/Q imbalance with positioning
Increase FIO2, TV, RR, maybe PEEP to improve oxygenation
Position that helps lung capacities
Sitting, some say prone
Nerve injuries caused by: (3 things, and common component of all causes)
- Transection (trauma, surgical maneuvers)
- Compression, kinking (against bony prominence, 2 immovable structures, or a hard surface)
- Stretch (causes conduction changes, axonal disruption, or interruption of vascular supply) Common in sciatic or brachial plexus
- Common component of all: Ischemia
Patient risk factors for peripheral nerve injuries
- Male
- Increased muscle decreased adipose
- Body habitus (underweight, obese, bulky)
- DM, HTN, PVD, neuropathy, ETOH
- Smoking within 1 month of surgical procedure
Most common nerve injury in anesthetized patient
Ulnar Neuropathy
Ulnar nerve injured when:
Compressed between medial epicondyle and armboard or bed
Recommendations to avoid ulnar neuropathy
- Tuck arms at the side of the body with palms facing inward
- Place arms in supine position (palm up) and abduct <90 on arm board
- Avoid over flexion of the elbow if secured across chest or in lateral position
Brachial Plexus Injury vulnerable in ___ position
Almost every surgical position (2nd most common peripheral nerve injury)
- Turning head stretches and compresses the contralateral brachial plexus under the clavicle
- Shoulder braces-place over acromion and distal clavicle (not mid clavicle or root of neck)
- Lateral decubitus compresses lower shoulder/axilla - axillary roll caudal to dependent axilla relieves pressure
Common peroneal injury
cause, presentation, prevention
Most common injury in lithotomy position
- Happens when lateral knee is compressed against stirrup
- Presentation: Foot drop, loss of dorsal extension of toes, inability to evert foot
- Prevention: Pad between leg and stirrup, flex knees with minimal rotation
Sciatic injury
cause, presentation, prevention
- Cause: Excessive flexion of hips from overstretching in lithotomy or sitting with legs strait
- Presentation: Weakness in all muscles below the knee, foot drop
- Prevention: Pad under buttocks, avoid external rotation of hips, flex table at knees
Femoral nerve injury
Cause, Presentation
- Cause: Trapped under inguinal ligament from extreme flexion/abduction of thighs or excessive traction during lower abdominal surgery
- Presentation: Decreased knee jerk, loss of flexion of hip and extension of knee, reduced sensation over anterior thigh
Saphenous nerve injury
Cause, presentation, prevention
- Cause: Medial tibial condyle compressed by leg support in lithotomy position
- Presentation: Parasthesia along medial/anteriomedial calf
- Prevention: Pad between leg and stirrup
Anterior tibial nerve injury
Cause, presentation
- Cause: Feet plantar flexed for extended period of time (sitting, prone)
- Presentation: Foot drop
Obturator nerve injury
Cause, presentation, prevention
- Cause: Excessive flexion of thigh to groin, excessive traction during lower abdominal surgery or forceps delivery
- Presentation: Inability to adduct leg, diminished sensation along medial thigh
- Prevention: Minimize hip flexion
Postoperative visual loss treatment
Immediate ophthalmologist consult
Ischemic optic neuropathy
- 89% of POVL after prone spinal procedures
- Commonly caused by decreased ocular perfusion and increased intraocular pressure
Postoperative visual loss prevention
- Avoid hypotension, especially if pt has history of hypertension
- Avoid direct pressure over eyes
Corneal abrasion
Most common type of eye injury
- Eyes should be protected and frequently checked during surgery
- Usually resolves without sequelae in several days
Facial nerve injury
Cause and branches of facial nerve
- Cause: Face straps that are tight across face with prolonged use
- Branches of facial nerve: Two zebras bit my cat
- Temporal
- Zygomatic
- Bucal
- Mandibular
- Cervical
Compartment Syndrome
- Damage to neural and vascular structures from tissue swelling
- Increased pressure and decreased perfusion in muscles with tight fascial borders
Venous Air Embolism
Positions, cause, manifestation
- Positions: Sitting position or any where negative pressure gradient exists between right atrium and veins at operative site (spinal surgery)
- Manifestation: Small amounts of air-decreased SaO2, decreased EtCO2, hypotension, arrhythmias. Large volume-cardiac arrest
Venous air embolism on monitors
- Esophageal or precordial stethoscope: mill-wheel murmur
- Precordial Doppler: place over 3-6 intercostal space to right of sternum after in sitting position
Venous Air Embolism treatment
- Surgeon flood field with saline, apply bone wax to boney edges
- Aspirate through CVP, give 100% O2
- Head down, tilt to left
ETT displacement with surgical positions
Right mainstem with steep Trendelenburg and neck flexion
Airway edema with surgical positions
- Edema in face or tongue says pharynx is edematous
- Prone/Trendelenburg: increased hydrostatic pressure
- Sitting position: WIth excessive neck flexion-venous drainage from head impaired
- Equipment may limit lymphatic drainage (oral airway, ETT, esophageal stethoscope)
Where to place pillow during lawn chair position
Under patients knees
- Decreases back pain
- Facilitates venous drainage from LE
- Decreases anterior abdominal wall tension during closure
Attention to ___ during lithotomy position
-Fingers when arms are at sides and the feet of OR table are lowered
Moving the table during lithotomy position
Also HD effect of movement
- Legs elevated and lowered simultaneously
- Leg elevation=increase in venous return-transient rise in CO/ICP
Alterations in ____ most responsible for hemodynamic changes during anesthesia position changes
Pre-load
Nerves at risk for injury in lithotomy position
- Peroneal (most common) and Saphenous-leg compressed by leg support (manifestation=peroneal-foot drop, saphenous-paresthesia along medial/calf)
- Obturator, femoral, sciatic-hip flexion >90 (manifestation=obturator-inability to adduct leg, decreased sensation along medial thigh, femoral-loss of hip flexion/knee extension, sciatic-weakness in all muscle below knee, foot drop)
Compartment syndrome from lithotomy position
From leg holders-inadequate perfusion
- Rare but can progress to rhabdo and/or reperfusion injury
- Surgical time>2 hours increases risk
Axillary roll in lateral decubitus position
Prevents compression injury to the brachial plexus on dependent side
Monitor SaO2 in ___ arm in lateral decubitus position
Dependent arm (to assess compromised blood flow and bundle compression
Flex point for lateral decubitus position
Should be under dependent iliac crest (not rib cage) to prevent compression of inferior vena cava
___ space on neck for sitting position
At least 2 fingerbreadths between neck and mandible to prevent midcervical tetraplegia
Sitting position effect on BP in brain
Every 1 inch change of cuff position there is a 2mmHg rise or drop in MAP (or 1.25cm-1mmHg)
-Measure vertical distance between external auditory meatus and BP cuff, brain MAP will be 8-24mmHg lower
Turning the patient from supine to prone
- Place on 100% FiO2
- Disconnect from breathing circuit for turn
- CRNA controls airway/head/neck
- Check breath sounds after intubation and after positioning
Head and neck position when prone
Neutral position, avoid hyperextension or lateral rotation of neck (may compromise spinal cord blood flow)
Arm position when prone on arm boards
Alongside head on padded arm boards, flexed and slightly abducted (<90) with forearms/hands lower than shoulders
-Pad under shoulders (avoid stretching brachial plexus)
Arm position when prone at sides
Natural position, palms facing thighs using plastic or metal arm sleds with sufficient padding
Prone position head inspection
Head, eyes, face, airway must be checked every 15 minutes to ensure weight is on bony structures only and no pressure on eyes
