Positioning Flashcards
In the supine position, making sure the patient’s hands are supinated protects what?
Supinated hands protects the ulnar nerve
Weight limit and length of an OR table?
Weight: 136 kg (300 lb)
Length: 80.7 inches
What is a way to protect the back in the supine position?
Pillow under knees
What can cause stretching of the brachial plexus?
Neck extension, abduction of arm over 90 degrees, or arm fell off the table
What causes compression of the radial nerve? What does this lead to?
Compression from surgical retractors, ether screen, mismatched arm board, BP cuff going off too frequently
Wrist drop, weakness/numbness in 1,2 ring fingers, inability to extend elbow
What is the most common peripheral nerve injury? What are s/s of this?
Ulnar Nerve, compressed between olecranon and medial epicondyle or stretching
S/S: inability to abduct/oppose pinky, weakness/numbness on 4th/5th fingers, claw hand
How would you prevent ulnar nerve injury?
pad arm boards, avoid compression by strap, assure surgical personal doesn’t compress the arm, place BP cuff proximal to ulnar groove, avoid prolonged flexion of elbow
What physiological changes occur in the supine position?
Cardio: initial increase in venous return (increase CO, BP), reduced venous drainage from lower extremities, IVC compression if big belly
Resp: FRC decreases 800 mL (give PPV)
Head: minimal change in CBF due to autoregulation
What is trendelenburg used for?
Central line insertion (prevents air embolism), hypotension
Abdominal and laparoscopic surgery
(Reverse trendelenburg is good for upper abdominal surgery)
What physiologic changes occur in the trendelenburg position?
Cardio: increases venous return/ BP
Resp: increases work of breathing, V:Q mismatch, decreases FRC, increases PIP, risk aspiration, risk of face/airway edema
Head: increased ICP, increased intraocular pressure
Note: consider another position for patient with glaucoma or CNS disease
What physiological changes occur in reverse trendelenburg?
Cardio: reduced preload, CO, and BP, increased HR, RAA activation, venous pooling
Resp: FRC increases, ventilation is easier
Head: ICP decreases
Uses: upper abdominal/laparoscopic surgeries
What is the most common lower extremity nerve damaged? How is it commonly damaged? What are s/s?
Common peroneal nerve injured from compression of lateral knee against stirrup in lithotomy or in lateral position
s/s: foot drop, inability to evert the foot, loss of dorsal extension of the toes
How is the sciatic nerve injured and what are s/s?
Stretching or excessive external rotation
s/s: weakness/paralysis below the knee, numbness in foot and lateral calf, foot drop
How is the femoral nerve injured and what are the s/s?
Injured with compression at pelvic brim by retractor or angulation of thigh or abduction of thighs and external rotation of hips
s/s: loss of flexion of hip and loss of extension of knee, decreased sensation of superior thigh
What positions put a patient at risk for lower extremity compartment syndrome with long surgeries?
Lithotomy and lateral decubitus
How much does perfusion pressure drop for each 2.5 cm an extremity is raised above the heart?
Perfusion pressure drops 2 mmHg for each 2.5 cm an extremity is above the heart
What physiological changes happen in the lithotomy position?
Cardio: increased venous return/preload, increase CO/BP, less perfusion to lower extremities
Pulm: if pressure on belly, reduced lung compliance/TV/VC, aspiration risk
Head: increased CBF/ICP
What are risk factors for blindness during a surgery?
prone position, operative hypotension, large blood loss, large crystalloid use, anemia, smoker, diabetic, vascular pathology, HTN, male
What is thoracic outlet syndrome? Why should you test for it?
Test by having the patient clasp hands behind head for 2 min and see if there is numbness/tingling or diminished pulses
If the test is positive, the patient should not have their arms elevated in prone during the procedure, instead tuck the arms down at the patient’s sides
What physiologic changes occur with prone position?
Cardio: IVC/Aortic compression or venous pooling causes hypotension
Pulm: V:Q mismatch (posterior ventilation, anterior perfusion), compliance decreases, peak pressure increase, work of breathing increases (use PPV)
Head: turned head leads to increased ICP, excessive turning can lead to obstruction
Why would you place a patient in lateral decubitus position?
Thoracotomy, kidney, shoulder, hip surgery
Thoracic surgery, one-lung ventilation
Lateral position: Physiological changes?
Cardio: minimal to no change (kidney rest can cause vena cava obstruction)
Pulm: nondependent (top) lung is better ventilated, dependent (bottom) lung is better perfused (VQ mismatch)
Head: minimal changes
What physiologic changes occur in the sitting position?
Cardio: hypotension, lower extremities pooling of blood, HR and SVR increase
Resp: Lung volume/compliance increases, work of breathing is easier
Head: decreased ICP, caution hypoperfusion
What is a venous air embolism, what are risks, what are s/s?
VAE is the inability of venous sinuses to collapse, can be lethal
VAE is a risk when the surgical site is above the level of the heart
s/s: change in heart tones, new murmur, dysrhythmias, hypotension, desat, decreased EtCO2, exhaling nitrogen, cardiac arrest
