Positioning #2 Flashcards
What cardiovascular changes would you anticipate in lithotomy position?
- Elevation of legs increases venous return/increases preload to heart with a transient increase in CO and BP
- perfusion to lower extremities is reduced
- perfusion pressure changes 2 mmhg for each 2.5 cm that a given point varies in vertial height above or below the heart
- After legs are put down, venous blood will pool in them. Always check BP after putting legs down
What ventilatory changes would you anticipate in lithotomy position?
- Depending on the degree of hip flexion, abdominal contents may push up on the diaphragm and impede excursion
- reducing lung compliance
- decreasing TV and VC
- increases risk of aspiration
What cerebral changes would you anticipate when putting your pt in lithotomy position?
- transient increase in cerebral venous blood flow and increase in intracranial pressure with legs elevated
What is the Wilson frame?
- frame used to prone a patient; it is open under abdomen and chest to allow for ventilation
What is a jackson table?
- special table used if position changes are needed during the procedure
- *the human rotisserie
What are the different options for head rests when pt is prone?
- head rest with mirror
- horseshoe headrest
- watch eyes, nose, bony structures of face
- make sure head and neck are aligned
- Mayfield head tongs/pins (pictured)
- watch for bolt slippage
- want natural neck alignment
- eyes, nose, and chin are free with nothing touching them
How is a patient put into prone position?
- While patient is still on the stretcher:
- induction/intubation
- line placement
- NGT/OGT, esoph stethescope, bit block
- foley
- good eye protection
- secure everything
- Consider disconnecting the monitors
- Turn pt to prone postion onto OR table (you in charge of head/neck/airway
- Once turned, check breath sounds again
- make sure monitors are on and working
- check IV and art line
- Check for excessive pressure on eyes, nose, chin, upper extremities, breasts, genitals, etc
- Chest and hips should be supported to allow for free abdomen for diaphragmatic movement and increased venous return
How do you position the head in prone position?
- Head may be turned to side if they have adequate mobility
- caution: obstruction of jugular venous drainage and vertebral artery flow
- Head supported face down with its weight on bony structures
- Neck should be in neutral alignment, not excessive flexion or extension
- Eyes, nose, ears should all be free of pressure
What are the risks for the eyes in prone position?
What are the risk factors for blindness in the OR?
- Corneal abrasions
- direct trauma, dry eye, or swelling
- treatment is antibiotic ointment, eye patch
- Blindness
- ischemic optic neuropathy
- via central vein or artery obstruction
- via sustained, direct pressure on the eye/retina
- visual changes/ partial or complete blindness
- Risk factors include prone position, operative hypotension, large operative blood loss, large crystalloid use, anemia, smoker, diabetic, patients with vascular pathology or HTN, males
- Caution in spinal surgery and cardiac surgery
- ischemic optic neuropathy
What do you do with the extremeties in prone position?
- Arms:
- on boards by the head
- abducted less than 90 degrees
- extra padding at elbow
- prevent shoulder from sagging
- watch for thoracic outlet syndrome
- or tuck arms at sides
- legs:
- slightly flexed
- compression socks/SCD
What CV changes would you expect with a proned patient?
- IVC and Aortic compression- hypotension
- Venous pooling in lower extremities- hypotension
- leads to decreased preload, CO, and BP
- Hypotension associated with the move to prone position must be anticipated, monitored, and treated as necessary.
- prolonged hypotension in addition to pressure on the face/eyes may lead to blindness!!
What ventilatory changes would you expect in a proned patient?
- V:Q mismatch
- posterior would have ventilation > perfusion
- anterior would have perfusion > ventilation
- Cephaled displacement of diaphragm
- decreases lung compliance
- increased peak airway pressures
- increased WOB
- **Use rolls/bolsters to free chest
- PPV overcomes compression effects
What cerebral blood flow changes would you anticipate in a proned patient?
- Turning head obstructs venous drainage leading to increased cerebral volume and ICP
- Excess flexion or turning can obstruct vertebral artery flow
- spinal cord injury can be caused by stretch
What is lateral decubitus position used for?
What special accomodations does it require?
- Used for:
- thoracotomy
- kidney
- shoulder
- hip surgery
- Requires special positioning of:
- head support- neutral position
- avoid misalignment of cervical spine or stretch of brachial plexus
- Limited pressure on dependent eye and ear
- axillary roll placed caudad to and outside of lower axilla (pic on front of card)
- head support- neutral position
What should you do with the extremeties when positioning your patient laterally?
Where does the safety strap go?
- Arms:
- dependent arm on a padded arm board perpendicular to torso
- Non-dep arm supported over folded bedding or suspended with armrest
- Legs:
- padding between knees and flexed dependent leg (to avoid saphenous nerve injury)
- padding on bed (to avoid common peroneal nerve injury)
- Anterior/posterior support- bean bag/hip posts
- Safety strap- between head of femur and iliac crest
What cardiovascular changes would you expect when you postion your patient laterally?
- Minimal changes
- no change to CO unless venous return is obstructed
- if the kidney rests against the vena cava
- Non-invasive BP cuff measurements will be different in the two arms
- higher in dep
- lower in non-dep
What ventilatory changes would you expect in your laterally positioned pt?
- V/Q mismatch
- If awake and spontaneously breathing:
- dependent lung is both better perfused and better ventilated
- lung volumes (FRC, VC, TV) decrease
- Anesthetized but spontaneously breathing
- Non-dep lung better ventilated and dep lung better perfused (V/Q mismatch)
- Anesthetized, mechanically ventilated:
- Non-dep lung overventilated and dep lung over perfused (worse V/Q mismatch)
What changes to cerebral blood flow would you anticipate in a pt positioned laterally?
- Minimal change unless there is extreme flexion
When is the sitting position used?
- Used for:
- cranial surgery
- shoulder
- humoral
- Facilitates venous drainage
- excellent surgical exposure
How should you position the head when placing your patinet in sitting position?
- Head should be fixed in pins or taped in place
-
avoid excessive cervical flexion (want at least two finger breadths between mandible and sternum)
- obstructs outflow causing hypoperfusion or venous congestion in the brain
- stretches cervical nerve roots
- can obstruct ETT
- can place pressure on the tongue (swelling)
- Avoid rigid bite-block that can cause tongue eschemia
- watch spinal alignment
How can you ensure your patient is well positioned in sitting position?
- Arms should be supported- avoid traction pulling down on shoulders
- Buttocks should be positioned in the break of the table
- Flex knees and hips- decrease stretch of sciatic nerve
- compression socks/SCD
- feet supported and padded
What cardiovascular changes would you anticipate for a pt in sitting position?
- Pooling of blood in lower extremeties decreases preload, CO, and BP
- HYPOTENSION!!
- HR and SVR increase as a compensatory measure (blunted by anesthetics)
- Treatment: IVF, vasopressors, adjustments of ansethetic depth, compression socks/devices
What ventilatory changes would you anticipate in a patient in sitting position?
- Lung volumes and capacities increase
- compliance increases
- WOB is easier
- Mechanical and spontaneous breathing is easier in this position
What changes to CBF would you anticipate in a pt in sitting postition?
- Cerebral blood flow decreased
- ICP decreased
- watch positioning which can impede arterial and venous blood flow, causing hypoperfusion or venous congestion of the brain
- zero art line at circle of willis
What is a major risk associated with the sitting position?
- Venous air embolism is a risk any time the surgical site is above the level of the heart
- VAE prevents venous sinuses from being able to collapse
- can be a lethal complication
- Signs of VAE:
- change in heart tones (wind mill murmor)
- new murmor
- dysrhythmias
- hypotension
- desaturation
- decreased ETCO2
- nitrogen in exhaled gas
- circulatory compromise
- cardiac arrest
- detected with TEE or precordial doppler
Where would you hear the wind mill murmor associated with VAE?
- Heard via doppler placed at the parasternal border
- 2nd-6th intercostal space
How is VAE treated?
- Flood surgical field with NS, apply wax to cut bony edges, close any open vessles
- D/C nitrous
- place on 100% FiO2, peep
- t-berg position
- aspirate air from right atrium via a catheter
