Flashcards in Positioning Deck (72)
How should patients be moved during surgery?
Slow position changes, especially at the en of along case
Length of the OR table
What can happen with irregular head positioning?
Brachial plexus injury, excess swelling,
Where is the drawsheet placed when tucking the patient's arms?
Under the pt's hip or torso. NOT under the mattress.
How long is the anesthesia bed?
How is lumbar support obtained in the supine position?
Slight flexion of the hips and knees by placing a pillow under the knees (be careful that it isn't too hard or too high or could cause problems with venous return). With bend of the legs, should have SCD and TEDs to improve venous return and decrease risk of DVT
What are the mechanisms of nerve injury?
Stretching, compression, kinking, ischemia, transection
How can brachial plexus injury occur in the supine position?
Neck extension or turned to one side, arm abduction > 90 degrees, arm/arm board falls off the table.
Sternal retraction during cardiac surgery is also associated with plexus injury.
- Overall these are mostly due to stretching
S/S of brachial plexus injury
Damage can be specific or general to the entire arm
- Electrical shock / burning sensation shooting down arm
- Arm numbness or weakness
- Absent or weak motor control of shoulder and elbow
How does injury to the radial nerve occur in the supine position?
External compression of the radial nerve against the lateral aspect of the humerus from:
- Surgical retractors
- Ether (anesthesia) screen
- Mismatched arm board
- Repeated BP cuff inflation
Injury to the radial nerve causes
Wrist drop, weakness in abducting the thumb, and numbness of the posterior thumb, and first 2 fingers
This is the most common nerve injury in the supine position
Ulnar nerve injury is more common in (males/females)
How does ulnar nerve injury occur?
Stretch and compression
Compression of the nerve in the cubital groove between the olecranon of the ulna and the median epichondyle of the humerus.
Stretch from severe elbow flexion, dislocation with pronation of the hand, nerve dislocation over the median epichondyle with stretching/compression against the bed.
Symptoms of Ulnar Nerve Injury
Inability to abduct or oppose the 5th finger. Weak grip on the ulnar side of fist.
Loss of sensation of 4th and 5th fingers
Atrophy of intrinsic hand muscles
How to reduce the risk of ulnar nerve injury
Pad the arm boards
Supinate the arms
Make sure that surgical staff aren't compressing the patient's arm
Avoid downward compression from strap
Place the BP cuff proximally so that it doesn't compress on the ulnar groove/cubital tunnel
Avoid prolonged FLEXION of the elbow!**
CV effects of the supine position
MINIMAL effects on circulation and perfusion
Initial increase in venous return (causes increase in preload, SV, CO, BP, and baroreceptor-initiated decrease in HR and PVR)
These measures will increase venous return to the heart
SCDs, TEDs, uncrossing the legs, padding the heels, pillow under the knees, knee/hip flexion
Effect of IVC compression
The IVC can become compressed by a large abdomen (pregnancy, obesity, ascites, masses, etc), decreasing venous return, preload, and CO.
Effect of the supine position on vent status
Slight upward displacement of diaphragm/compression of lung bases causes a decrease in FRC by 800mL
Exacerbated by muscle relaxants (because this causes the loss of chest wall recoil that normally opposes the want of the lungs to collapse)- this is overcome with PPV
Effect of the supine position on CBF
Benefits of trendelenberg
Tx of hypotension by increasing venous return
Decreasing risk of air embolism
Facilitates cannulation during central line placement
Improves surgical exposure for abdominal / laparoscopic surgery
Shoulder braces should be placed here
Over the acromioclavicular joint. This avoids pressure on the clavicle, which would compress the brachial plexus
What should you do if your patient starts sliding in trendelenberg?
You can extend the bed, and also make sure nothing is pulling from their movement.
Slide the patient back.
Place in reverse T if at an appropriate place in surgery
VCV effect of trendelenberg
1) Increase in venous return (as much as 1L extra into central circulation) and reversal of hypotension (use for hypotension is controversial- short term only!!). Remember that this increase in CO will also put more demand on the heart.
2) Activation of baroreceptors- decrease in SVR (vasodilation) and HR---this effect can make shock worse in the long run. Short term use only!
3) Decreased blood flow to the lower extremities
4) Compression of heart by abdominal contents
Effect of the trendelenberg position on ventilation
1) Abd contents move cephalad, impeding diaphagmatic excursion, compressing lung bases, decreasing FRC, and increasing PIP.
2) V:Q mismatch because perfusion of lung apex exceeds ventilation of lung apex
3) Aspiration risk
4) Face and airway edema, which can lead to airway obstruction
5) ETT shift into R mainstem
6) Pulmonary edema and congestion
These may be indicators of airway edema
Lip and periorbital edema
Effect of the trendelenberg position on the head
Increase in intracranial vascular congestion leading to increased ICP!
IOP rises as well.
Patients with IICP and severe glaucoma are not good candidates for this position
Surgical use of reverse T
Enhance exposure of the upper abdomen by shifting abdominal contents caudad (laparoscopic cholecystectomy)
Variations on reverse T may be used for shoulder, neck, breast, or intracranial surgery