Principles Positioning

Front 1

Positioning goal

Back 1

Allow optimal surgical access while minimizing potential risk to patient

Front 2

Surgical team work

Back 2

Knowledge, teamwork, timing, communication closed loop

Front 3

Factors contributing to physiological changes

Back 3

Surgical position. Length of time. Patty and positioning devices. Types of anesthesia. Surgical procedure.

Front 4

Use of sequential compression devices SCD

Back 4

Improve venous return. Prevent venous pooling in dependant areas

Front 5

Consequences of general anesthesia

Back 5

Myocardial depression and vasodilation leads to decreased cardiac output decreased blood pressure leads to blood pools independent body areas leads to decreased preload decrease stroke volume

Front 6

Cardiac Consequences of neuromuscular blockade

Back 6

Decrease venous return due to lack of muscle tone

Front 7

What is blunted by general anesthesia?

Back 7

Compensatory mechanisms such as increased heart rate increased systemic vascular resistance to counteract hypotension

Front 8

Cardiac consequences of prone position

Back 8

Increase in your CVP. Increase intrathoracic pressure. Decreased left ventricular volume. decrease venous return. Increase or decrease cardiac index

Front 9

Cardiac effects of lateral decubitus position kidney rest elevated

Back 9

Decrease blood pressure due to dependent leg position. Decrease venous return due to extreme flexion. Kidney rest, compresses the great vessels. Should lie under the dependent iliac crest

Front 10

Cardiovascular effect of opioids

Back 10

Slow heart rate. Decreased cardiac output. Decrease blood pressure.

Front 11

Cardiovascular effects on seated position

Back 11

Decreased cardiac index. Decreased CVP. Decrease pulmonary capillary wedge pressure. Increased svr. The higher the head is elevated during hypotension will increase risk of ischemia + hypoperfusion. Cardiac output decrease the more patient is raised

Front 12

What positions cause minimal hemodynamic changes

Back 12

Supine and lateral

Front 13

Cardiac effects of sitting, prone, flexed lateral position.

Back 13

Cardiac output and blood pressure decrease

Front 14

Regions elevated above the heart in the head up, sitting, and lithotomy positions may be at risk for?

Back 14

Hypoperfusion, hypotension, ischemia,

Front 15

Change in height between heart does what to mean arterial pressure

Back 15

Increases or decreases by 2 mm of mercury for every 1 in

Front 16

Describe cerebral pressures in relation to map in sitting position

Back 16

If arm map is 65 and cerebrum map is 50. For every 20 cm arrives there will be a 15 millimeters of mercury drop-in map

Front 17

When are hemodynamic changes minimal?

Back 17

When the patient is placed in a 45-degree, head up sitting position

Front 18

What happens to cardiac output when the patient is raised to 90° and why?

Back 18

Cardiac output decreases 20% if the patient is raised to 90° because venous blood pools in the extremities

Front 19

What are the effects of venous congestion in intracranial structures?

Back 19

Decrease cerebral blood flow

Front 20

How to prevent facial edema in the prone position?

Back 20

Position the head level or higher than the heart to minimize venous outflow obstruction

Front 21

What is the effect of combination of lithotomy and head down tilt

Back 21

Increase in myocardial function and oxygen demand, causing increase in CVP, pulmonary artery pressure, pcwp, and a decrease in cardiac output in patients with coronary artery disease and heart failure

Front 22

What happens to individuals with peripheral artery disease when lower extremities are elevated above the heart

Back 22

At risk for ischemia because of relative state of hypoperfusion. They are at higher risk for compartment syndrome

Front 23

What type of monitoring should be in place in procedures where the head is elevated and cerebral perfusion is a concern

Back 23

Invasive arterial blood pressure monitoring with transducer placed at the level of The Circle of Willis

Front 24

Cardiovascular effects of Trendelenburg position

Back 24

Increase in myocardial work as per Frank Starling curve

Front 25

Frank Starling mechanism

Back 25

Increase in end-diastolic volume, preload will increase cardiac contractility, will increase stroke volume. Increase contractility will make the curve higher

Front 26

Respiratory effects on the Supine position

Back 26

Decreased Force residual capacity and decreased total lung capacity

Front 27

Respiratory effects in prone position

Back 27

Improve VQ matching and oxygenation

Front 28

Respiratory effects in the lateral decubitus position 4 spontaneously breathing patients

Back 28

Ventilation and perfusion are greater in the dependent lung then in the non dependent lung in awake patients

Front 29

Respiratory effects in the lateral decubitus position for anesthetize patients

Back 29

Abdominal contents shift cephalad moving the hemidiaphragm of the dependent lung upward, decreasing ventilation in the dependent lung and reducing its compliance. Non dependent lung better

Front 30

Respiratory effects in the sitting position

Back 30

More favorable for ventilation. Less effect on lung volumes. Rib cage increases ventilation

Front 31

Respiratory effects in the Trendelenburg position

Back 31

Exacerbates effects of various positions. Increase Trendelenburg decreases Force residual capacity

Front 32

Respiratory effects in the lithotomy position

Back 32

Viscera shift cephalad limiting diaphragmatic movement, impacting oxygenation

Front 33

Perioperative peripheral nerve injuries are frequently attributed to what

Back 33

Incorrect surgical positioning

Front 34

Common component of all peripheral nerve injuries is

Back 34

Ischemia. Intraneural blood flow may be compromised by Stretch, compression, transection , kinking

Front 35

Patient factors attributed to perioperative peripheral nerve injury

Back 35

Advanced age, gender, extremes and body habitus, pre-existing conditions

Front 36

Perioperative occurrences related to ppni

Back 36

Positioning devices, prolong surgical procedure, and aesthetic of technique

Front 37

Intraoperative occurrences related to ppni

Back 37

Hypovolemia, hypotension, hypothermia, hypoxia, electrolyte imbalance

Front 38

Primary mechanisms of nerve injuries

Back 38

Transaction, compression, traction and stretch, kinking

Front 39

Nerve injury caused by improperly placing legs in candy cane stirrups

Back 39

Peroneal nerve injury

Front 40

Contributing factors to nerve injury

Back 40

Incorrect surgical positioning, positioning devices, surgical duration, patient characteristics, malfunctioning equipment

Front 41

What is considered prolonged surgical procedure in terms of time

Back 41

Greater than 4 hours

Front 42

What nerve injuries can be caused by positioning devices

Back 42

Brachial plexus injury if the onboard Falls or if using shoulder straps. Improper placement of axillary roll compressors neural and vascular structures and can cause compartment syndrome

Front 43

How do muscle relaxants contribute to nerve injury

Back 43

May contribute to stretch injury by allowing increased mobility of joints

Front 44

What injuries are caused with neuro axial and nerve block techniques

Back 44

Hematoma and needle trauma

Front 45

Underweight patient with a BMI of less than 22 is at risk for what type of nerve injury

Back 45

Ulnar neuropathy

Front 46

Patient with muscular physique is at risk for?

Back 46

Compartment syndrome

Front 47

Effects of obesity

Back 47

Large tissue masses Place increase pressure on dependent body part adipose tissue is poorly perfused

Front 48

Most common injured nerve

Back 48

Ulnar nerve

Front 49

Presentation and symptoms of ulnar nerve injury

Back 49

Claw hand, ring and Little Finger hyper-extended. Loss of abduction and adduction of fingers and flexion. Pain and numbness

Front 50

Actual Contributing factors to ulnar neuropathy

Back 50

Surgical positioning. Age greater than 50. Pre-existing disease. TOURNIQUET. Gender. Has a delayed onset of approximately 3 days

Front 51

What position do you put the arms in to prevent nerve injury

Back 51

Pad bony prominences. Supinating the arms in Supine position. Abduct arms less than 90 degrees when not tucked

Front 52

What type of nerve injury is a risk for almost all surgical positions

Back 52

Brachial plexus nerve injury

Front 53

How to avoid brachial plexus nerve injury

Back 53

Avoid head rotation away from abducted arms. Arm adduction less than 90 degrees. Avoid shoulder braces. Head in midline.

Front 54

Nerve Roots affected by brachial plexus injury

Back 54

C8, T1. Nerve may be compressed between first rib and clavicle

Front 55

Type of spinal cord injury

Back 55

Mid cervical flexion myelopathy with temporary or permanent quadriplegia

Front 56

Factors contributing to spinal cord injury

Back 56

Congestion in the veins draining the spinal cord with hypertension may result in decreased spinal cord perfusion. Avoid hyperflexion of the head and neck

Front 57

Effect of Trendelenburg and reverse Trendelenburg positions

Back 57

Increased CVP. Increased intraocular pressure. Increased ICP. Edema to the face, tongue, oropharyx and eyes. Decreased perfusion pressure to brain

Front 58

How to avoid common peroneal injury in the lithotomy position

Back 58

Both legs should be elevated and lowered simultaneously. To avoid common peroneal injury

Front 59

Effects of common peroneal nerve injury

Back 59

Foot drop

Front 60

Effects of straight legs in lithotomy position

Back 60

Kinking injury leading to stretch of the sciatic nerve

Front 61

Things to check when patient is in lateral decubitus position

Back 61

Ensure dependent ear and eye are free of pressure. Assess perfusion to dependent arm with cap refill check

Front 62

What does the auxiliary role do

Back 62

Please. Dependent side slightly caught up to the excella. Relieves pressure exerted on the shoulder, auxiliary vessels and brachial plexus.

Front 63

What position is preferable for intracranial procedures

Back 63

Prone position to avoid the risky sitting position

Front 64

Perioperative vision loss is associated with what kind of surgery

Back 64

Spine, orthopedic joint and cardiac surgery. Effects can range from decreased visual Acuity to complete vision loss

Front 65

Contributing factors to perioperative vision loss

Back 65

Duration in prone position. I compression. Increased intraocular pressure. Hypoperfusion. Anemia

Front 66

Causes of perioperative vision loss

Back 66

Ischemic optic neuropathy. Central retinal artery occlusion. Cortical blindness. Glycine toxicity.

Front 67

How does ischemic optic neuropathy occur

Back 67

Decreased perfusion to the optic nerve due to decreased blood flow in the internal carotid artery. I o n after prone spinal surgery is very common

Front 68

Ischemic optic nerve injury contributing factors

Back 68

Spinal surgery. Prone position. Large blood loss. Wilson frame usage.

Front 69

Most common causes of i o n

Back 69

Hypoperfusion and elevated intraocular pressure

Front 70

Ocular perfusion pressure equals

Back 70

Map - intraocular pressure

Front 71

Ocular perfusion pressure decreases caused by

Back 71

General anesthesia. Anything that lowers map. Hypertension. Hemorrhage. Hypovolemia

Front 72

What position will affect intraocular pressure

Back 72

Steep Trendelenburg where the head position is lower than the heart increases intraocular pressure

Front 73

What is the least preferred head support technique in prone position

Back 73

Horseshoe adapter in prone position

Front 74

Central retinal artery occlusion when is recovery of vision possible

Back 74

If blood flow is restored within 4 hours

Front 75

Risk factors for c r a o

Back 75

Hypertension. Cardiovascular disease. Increased BMI. Open-angle glaucoma. Sickle cell anemia

Front 76

What is compartment syndrome

Back 76

Tissue swelling as a result have increased pressure and decreased tissue perfusion in muscles with tight faccia borders

Front 77

What can happen with compartment syndrome

Back 77

Systemic hypotension. Vascular obstruction of major extremity vessels cuz by intrapelvic retractors. External compression of elevated extremity. Swollen muscle compresses nerves and blood vessels

Front 78

Positions at risk for compartment syndrome

Back 78

Trendelenburg and lithotomy. Legs should be periodically lowered to the level of the body if the procedure lasts more than two to three hours

Front 79

What causes venous air embolism

Back 79

Negative pressure sucks air from the incision into the right side of the heart, decreases gas exchange and causes a VQ mismatch.

Front 80

What causes venous air embolism

Back 80

Any position where there is a negative pressure gradient between the right atrium and veins at the operative site

Front 81

How to detect venous air embolism

Back 81

End-tidal CO2 will drop. Presence of end-tidal nitrogen. Mill wheel murmur heard through esophageal stethoscope.

Front 82

Gold standard for detection of venous air embolism

Back 82

Transesophageal echocardiogram

Front 83

Who's at risk for paradoxical air embolism. What happens in paradoxical air embolism

Back 83

Patience with patent foramen ovale. Right atrial pressure is greater than left atrial pressure and air enters systemic circulation

Front 84

Alternative to TEE

Back 84

Transcranial Doppler