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85 Cards in this Set
- Front
- Back
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What are the types of pt positions in OR?
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*dorsal decub
*lateral decub *ventral decub |
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what are the different dorsal decub positions?
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*supine (tberg/reverse tberg)
*frog leg *lithotomy |
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what are the lateral decub positions?
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*semiprone
*flexed lateral (jackknife) |
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what are the different ventral decub positions?
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*prone
*prone jackknife *prone kneeling |
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If a pt is hemodynamically unstable, what should you do with their position?
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delay until pt is stable
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What are the respiratory changes in dorsal decub?
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*gravity inc perfusion to dependent lung fields
*dec FRC (r/t abdominal viscera on diaphragm) |
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what are th cv changes in dorsal decub?
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*horizontal supine - minimal
*supine w/head up or down - --> presure gradient to heart |
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in dorsal decub, venous return changes are r/t?
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intrathoracic pressure changes from respirations
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what happens to a pt in tberg?
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*inc pressure in cerebral veins
*inc ICP, CVP, IOP *congestion in nares, eyes *inc preload --> inc PSNS flow and dec HR/CO |
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what nerves are activated in aortic and carotid baroreceptor response to inc preload?
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*vagus (CN VI)
*glossopharyngeal (CN IX) |
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tberg can cause what pulm changes?
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*atelectasis
*V/Q mismatch *dec FRC *dec pulm compliance *poss upper airway obstruction |
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what happens to pt in reverse tberg?
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*BLE venous pooling
*dec preload/CO/systemic perf *inc SNS tone/HR/PVR *inc FRC |
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what are the uses of tberg?
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*hypotension
*better surgical exposure of abd *prevent venous air emboli |
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what has been shown to improve MAP in pt tberg that does not affect CO/pulm fxn/ICP?
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*raising the legs
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what are the variations in lithotomy position?
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*std
*low *high *exaggerated |
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what does std lithotomy look like?
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*thighs flexed 90deg
*knees bent/parallel to floor *arms @ side/on armboards <90deg |
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what happens to a pt in std lithotomy in CV?
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autotransfusion of volume from legs inc preload/CO
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when is std lithotomy used?
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*gyne
*uro |
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what is a pt @ risk for when std lithotomy position is complete and pt going to PACU?
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*hypotension when pt placed supine
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what happens to pulm status in std lithotomy?
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*dec VC
*dec FRC *dec TV |
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when might a low lithotomy position be used?
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lap hyster
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what is the difference in hip flexion b/w low and std lithotomy?
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*low > 30-45%
*std > 90deg |
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why is high lithotomy used?
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*to improve access to perineum
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what makes high lithotomy different from std/low?
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*thighs flexed 90deg
*over trunk *legs almost fully extended |
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how is an exaggerated lithotomy position achieved?
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in stages
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*what is an adverse effect of exaggerated lithotomy?
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*a/w high incidence of LE compartment syndrome
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does exaggerated lith improve ventilation?
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NO
it restricts ventilation |
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what are the complications of dorsal decub positions?
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*postural hypotentsion
*pressure alopecia *ischemic necrosis of bony areas *backache *nerve palsies |
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what is the most common nerve injury in lithotomy?
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common peroneal nerve
(a/w candy cane support) |
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what are some common traits that can cause common peroneal nerve injury?
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*candy cane support
*smokers *low BMI *surgery >2hrs |
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what is compartment syndrome in lithotomy?
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*inadequate perfusion to extremity --> ischemia, edema & rhabdo from tissue pressure
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what OR table position can cause digit amputation?
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lithotomy when table foot raised back
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what kind of changes would you expect if a pt is in lateral decub?
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*venous pooling BLE r/t legs below heart
*extreme flexion can compromise venous return |
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what happens to dependent lung perfusion in lateral decub?
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*decrease compliance
*atelectatsis *non dependent lung underperfuse & overventilated *overall there is a V/Q mismatch |
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what are some variations to lateral decub?
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*semisupine or semiprone
*semilateral |
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what is important about the semiprone position?
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*dependent arm supported
*nondependent arm in arm rest *place pulse ox on nondependent arm to assure adeq circ *most accurate NIBP in depen arm |
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what is the purpose of lateral jackknife?
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widen intercostal spaces to facilitate thoracotomy incision
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during lateral jackknife, what happens to pt's thighs?
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*table is flexed so they become lateral to trunk
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what is a kidney rest?
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*elevation of the pt under the dependent iliac crest to increase lateral flexion
*improves access to upside kidney |
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what are the complications of lateral decub?
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*back/neck pain
*compartment syndrome *contusion/folding of dep ear *inc IOP r/t dep eye ischemia *suprascapular nerve injury (r/t axillary in wrong position) |
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what does the prone position allow?
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*access to post fossa/spine/butt/post LE/perirectal area
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what must be checked after pt is turned prone?
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*BBS
*ETT placement |
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what should you check on the pt when the pt is prone?
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*eyes
*nose *airway should be checked throughout case |
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what supporting devices should be used when pt is prone?
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*mayfield tongs
*chest rolls *prone pillows |
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how should the head be placed in prone?
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*neutral
*to the side |
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what happens to MAP if pt kept horizontal (prone)?
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unchanged
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what happens if a pt is not positioned correctly in prone?
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*dec preload
*cephalad mvmt of diaphragm *dec FRC/compliance *inc PAWP |
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what happens to the pt if the head is extremely flexed in prone?
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dec cerebral venous return (2-3 fingerbreadths b/w chin & chest avoids this)
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What are some complications to eyes when pt prone?
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*ION > ischemic optic neuropathy
*central retinal artery occlusion |
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how many cases have been registered w/ASA in prone blindness?
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79 cases
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what type of positioning is most common in cases where blindness occurred?
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prone
53 of 79 pts had spinal surgery |
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which is more prevelant in blindness when prone (ION or central retinal artery)
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ION 83% to CRA 13%
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what is the likelihood that pt's will recover sight after ION?
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44% of pts recovered vision
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what are the risk factors for prone position blindness?
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*long spinal surgery
*massive blood loss *intraop hypotension *excessive crystalloid *anemia *hemodilution *venous congestion *edema of the head |
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what are the pt risk factors in prone position blindness?
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*HTN
*DM *morbidly obese *atherosclerosis *smoking |
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what should the MAP remain during spinal surgeries?
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70 - 100
*if pt is HTN, then try to maintain toward higher end |
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what kind of nerve injury can happen when pt prone?
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brachial plexus
r/t > abduction of arm >90deg turning head, compression from chest rolls |
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what could happen to cerebral perfusion during prone positioning?
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*impaired
r/t head/neck rotation & neck flexion (extreme) |
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why is the sitting position used?
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*post cervical
*post fossa *shoulders |
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what are the CV changes during sitting position?
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*BLE pooling --> hypotension
*SNS/renin-angio-aldos system activation *dec atrial pressures |
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where is the most accurate reading of CPP during sitting position?
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*Circle of Willis is where MAP should be measured
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what are some complications of sitting position?
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*postural hypotension
*air embolus *midcervical tetraplegia |
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decribe what to look for if a pt gets an air embolus while in sitting position?
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*surg field above heart
*foam *inefficient CO *pulm HTN *dec gas exchange |
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what happens if a pt has a PFO and gets an air embolus?
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*goes to left side of heart and out to circulation
*dysrhythmia/cardiac arrest |
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what size are most air emboli?
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small
*usually do not have complications |
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how are air emboli detected?
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*early w/precordial doppler US
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describe midcervical tetraplegia?
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*paralysis below C5
*hyperflexion of neck r/i compromised blood flow |
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what might be some s/s of midcervical tetraplegia?
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*venous & lymph obstruction from prolonged & extreme neck flex
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what is a pneumocephlus?
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air in the brain
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what are the clinical signs of pneumocephalus?
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similar to inc ICP
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what are the causes of ulnar neuropathy?
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*elbow flexion
*male *external compression *dec adipose tissue in elbow |
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what is the process of ulnar neuropathy?
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*cubital tunnel retinaculum (CTR) compression
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what are the s/s of ulnar neuropathy?
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*numbness
*tingling *pain |
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how do you avoid ulnar neuropathy?
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*keep hands/arms supine or neutral
*pad elbows |
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how does radial nerve injury happen?
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compression at lateral aspect of the arm below the lateral epicondyle of the humerus
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what are the s/s of radial nerve injury?
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*wrist drop
*weakness of abduction of thumb *loss of senstaion b/w thumb and index finger *inability to extend distal phalanx of thumb |
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how does the median nerve dysfxn come about?
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iatrogenic trauma to the nerve @ the AC fossa during venipuncture
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what are other ways of the median nerve dysfxn happen?
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stretch of the median nerve during elbow extension
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what are the s/s of median nerve dysfxn?
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*inability to completely extend elbow
*numness over the dorsal and palmar areas of the distal phalanges of the 1st & 2nd fingers |
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where is the anterior interosseous nerve?
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branch of the median nerve in the upper forearm
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how is the anterior interosseous nerve get damaged?
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compression from a tight arm restraint on the supinated arm
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how does the anterior interosseous nerve present?
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resembles compartment syndrome d/t ischemic injury; requires surgical decompression
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what is sensory neuropathy?
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*frequently tansient
*should resolve by postop day #5 *avoid postures that could aggravate *neuro consult should be done if symptoms persist |
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what is motor neuropathy in the post op period?
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*immediate neuro consult
*EMG studies |
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what doe EMG studies do to diagnose postop neuropathy?
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*assess location of lesion
*measure muscle response to nerve stim *response evaluated on degree of muscle contraction |
