Exam 2- Positioning (6/15/23) Flashcards
What is the most common surgical position?
- Supine
Arm boards must be secure if in use.
What are initial physiological changes to be expected when moving from sitting to supine?
- ↑ Venous return
- ↑ Preload
- ↑ SV
- ↑ CO
- ↓Tidal volume
- ↓ FRC
Describe arm abduction positioning (4)
- Arm out to the side, < 90 degrees
- Padded arm boards secured to the table and patient at the axilla
- The arms should be supine (palms up)
- Elbows padded and arm is secured with a Velcro strap
Describe arm adduction positioning (5)
- Arm tucked alongside the body
- Arms held along the side of body via draw sheet under the body and over the arm
- Hand and forearm are supine (palms up) or neutral position (palms toward body)
- Elbows are padded
- May tuck one arm if surgeon must stand on side of patient
Complications of the supine position (5)
- Backache
- Pressure alopecia
- Brachial plexus or axillary nerve injury if arms abducted > 90 degrees
- Ulnar nerve injury if hand/arm is pronated (palm down)
- Stretch injury when neck is extended and head turned away (brachial plexus)
What position is this patient in?
- Trendelenburg (head down)
Safety/general considerations with Trendelenburg position.
- Use a non-sliding mattress/pad to prevent the patient from sliding cephalad
- Avoid using bean bags or shoulder braces
- Consider making a mark at the level of the patient’s head on the sheet or pad so you can determine easily if the patient has slid
Pathophysiological considerations with Trendelenburg position.
- ↑ CO, ↑ Venous Return from lower extremities
- ↑ ICP, ↑ IOP, Facial Edema
- ↑ Intraabdominal Presure
- ↓ FRC and ↓ Pulmonary Compliance
- May need higher pressure in ventilated patients
- Risk of endobronchial intubation as abdominal contents push the carina cephalad
What position is this patient in?
- Reverse Trendelenburg (head up)
Safety/general considerations with Reverse Trendelenburg position.
- Use a non-sliding mattress/pad to prevent the patient from sliding
- Use a footrest or something under the feet to prevent the patient from sliding
Pathophysiological considerations with Reverse Trendelenburg position.
- Risk of Hypotension (↓ Venous Return, Venous pooling)
- Downward displacement of abdominal contents/ diaphragm (better ventilation)
- ↓ Perfusion to the brain
Name the positions
- Left Picture: Beach Chair Position
- Right Picture: Full Sitting Position
When will the patient be in the Beach chair position?
- Shoulder Cases
Beach chair position will have less severe hip flexion and slight leg flexion.
Describe the set-up of the full sitting position
- Head must be stabilized – taped to special headrest or rigid pins
- Hips are flexed < 90 degrees and knees slightly flexed for balance to reduce stretching of the sciatic nerve
- Feet are supported – prevent sliding
- Compression stockings/wraps to maintain venous return
- Keep at least two finger’s distance between the chin and sternum
Describe the set-up of the full sitting position
- Head must be stabilized – taped to special headrest or rigid pins
- Hips are flexed < 90 degrees and knees slightly flexed for balance to reduce stretching of the sciatic nerve
- Feet are supported – prevent sliding
- Compression stockings/wraps to maintain venous return
- Keep at least two finger’s distance between the chin and sternum
Sitting position risk
- Cerebral hypoperfusion and air embolism
- Pneumocephalus- accumulation of air in subdural space, pressure on the intracranial structure
- Quadriplegia and spinal cord infarction- hyperflexion of the neck
- Cerebral ischemia
- Peripheral nerve injuries (Sciatic nerve injury)
Pathophysiological consideration of the sitting position?
- Hypotension d/t ↓ venous return.
- ↓ MAP
- ↓ Cardiac Index
- ↓ Perfusion Pressure
- Improved ventilation in non-obese patients
What position is the patient in?
- Prone
Describe the prone position.
- Patient lying on stomach
- Arms at side tucked or outstretched (< 90 degrees), with flexion at elbows
- Head supported face down using a prone pillow, horseshoe headrest, or rigid fixation with pins in a neutral position without pressure on eyes, nose, mouth, and ears
- Avoid compression of breasts, abdomen, and genitalia
- Legs padded and slightly flexed at the knees and hips
- Compression stockings for lower extremities to prevent pooling
Why do you not turn a prone patient’s head to one side or the other?
- Risk of jugular occlusion or carotid occlusion
Risk of prone position
- Facial and airway edema
- Ulnar nerve injury if elbows are not padded
- Brachial plexus injury if arms are abducted > 90 degrees
- Post-op visual loss secondary to decreased perfusion/ischemia
- Eye injuries r/t head position
- ETT dislodgement biggest complication, document
- Loss of monitors and IV lines
Pathophysiological considerations for prone patients
- Edema of face, conjunctiva, larynx, and tongue
- ↑ Abdominal pressure
- ↓ Venous return through compression of the inferior vena cava
- ↓ CO
- Improved ventilation and perfusion in the lungs d/t shift to the dependent areas
What position is the patient in?
- Lithotomy
Describe the Lithotomy position
- Patient laying supine with legs up in padded or “candy cane” stirrups
- Arms tucked or on arm boards
- If using Trendelenburg or reverse Trendelenburg, need non-sliding mattress
- Hips flexed 80 -100 degrees and legs abducted 30 - 45 degrees from midline, knees flexed
- Lower extremities MUST be raised and lowered in synchrony together
- Foot of the bed is lowered, must protect the hands and fingers from crush injury
- Surgery > 2-3 hours, periodically lower the legs
Lithotomy risk
- Back pain
- Brachial plexus injury
- Ulnar nerve injury
- Common peroneal injury
- Lateral femoral cutaneous injury
- Compartment syndrome
For the Lithotomy Position, the_______ nerve is particularly prone to injury as it lies between the fibular head and compression from the leg support.
- Peroneal
For the Lithotomy Position, branches of the ____________nerves often pass directly through the inguinal ligaments and can be impinged and become ischemic within the stretched ligament.
- Lateral femoral cutaneous
Pathophysiological considerations for the lithotomy consideration.
- ↑ Venous return, ↑ CO, and ↑ ICP
- ↑ Intraabdominal pressure
- Displaces diaphragm cephalad
- ↓ Lung compliance and ↓ tidal volume
What position is the patient in?
- Lateral Decubitus Position
Describe the Lateral Decubitus position.
- Patient lying on non-operative (dependent) side and requires anterior and posterior support w/ rolls or bean bags
- Adequate head support… no pressure on eyes or ears
- Neutral position
- Dependent ear should be regularly checked
- Dependent leg is slightly flexed
- Arms are in front of the patient and both must be supported and abducted < 90 degrees
- Axillary roll placed between chest wall and bed, caudal to axilla to prevent brachial plexus compression
- Must place padding between the knees
For right Lateral Decubitus, what side of the patient will be down?
- RIGHT lateral decubitus = RIGHT side down
Safety/general considerations for the lateral decubitus position
- If bed flexed or kidney rest used, needs to be placed under iliac crest
- Inferior vena cava compression can occur
- Consider proper positioning to allow the best possible expansion of the dependent lung
- Ulnar nerve injury can occur if elbows are not padded
- Brachial plexus injury can occur if arms are abducted > 90 degrees
- ETT dislodgement; caution with use of LMA
Pathophysiological considers for the Lateral Decubitus position
- Venous pooling in lower extremities (use compression stockings/devices)
- V/Q mismatch due to inadequate ventilation to dependent lung and decreased blood flow to the nondependent lung
Peripheral nerve injury can be caused by what factors?
- Stretch
- Pressure
- Ischemia
Peripheral nerve injury can occur in as a little as 30 minutes.
Can nerve injury occur even when optimal positioning is performed?
- Yes
Overall, cases of nerve injuries have decreased, but are still a major legal cause to professional liability claims and can still occur even when optimal positioning is performed.
Which AANA standard relates to patient positioning?
- Standard 8: Patient Positioning
A patient is supine with the neck extended and the head turned to the right, away from surgical site. Which positioning complication may occur?
- Brachial plexus nerve injury
Shoulder braces used during Trendelenburg increases the risk of compression injury to the _______.
- Brachial plexus
What position is contraindicated in a patient with an increased ICP?
- Trendelenburg
If an arterial line is used for pressure monitoring in a patient placed in Reverse Trendelenburg, the transducer should be zeroed at _________.
- The Circle of Willis
This will represent arterial pressure at the base of the brain.
What position should the patient be placed in if there is a suspected cerebral air embolism?
- The patient should be positioned in a head down/Trendelenburg and left lateral decubitus position (Durant position).
- This aims to trap air in the right atrium and ventricle, thus minimizing the entry of air emboli into the right ventricular and pulmonary artery.
When placing a patient in a lithotomy position, why must the legs be raised and lowered synchronously?
- Prevent torsion and injury to lower spine
