Podcast
Questions and Answers
In shoulder arthroscopy, which positioning choice minimizes brachial plexus injuries?
In shoulder arthroscopy, which positioning choice minimizes brachial plexus injuries?
Why is it crucial to avoid assuming that a low blood pressure reading in the arm accurately reflects cerebral and coronary perfusion in a patient positioned in the beach chair?
Why is it crucial to avoid assuming that a low blood pressure reading in the arm accurately reflects cerebral and coronary perfusion in a patient positioned in the beach chair?
What is the primary reason for using an interscalene block during shoulder arthroscopy?
What is the primary reason for using an interscalene block during shoulder arthroscopy?
What is the key factor responsible for the reliability of mean arterial pressure (MAP) measured in the arm when a patient is in the supine position but not necessarily in the beach chair position?
What is the key factor responsible for the reliability of mean arterial pressure (MAP) measured in the arm when a patient is in the supine position but not necessarily in the beach chair position?
Signup and view all the answers
Which of the following statements accurately describes the role of the rotator cuff muscles in shoulder function?
Which of the following statements accurately describes the role of the rotator cuff muscles in shoulder function?
Signup and view all the answers
Which of the following is NOT a component of the rotator cuff?
Which of the following is NOT a component of the rotator cuff?
Signup and view all the answers
In the context of rotator cuff injuries, what is the direct consequence of the inflammation and swelling that occurs in the bursa?
In the context of rotator cuff injuries, what is the direct consequence of the inflammation and swelling that occurs in the bursa?
Signup and view all the answers
Which of the following is NOT a factor that contributes to the increasing popularity of arthroscopic shoulder surgery?
Which of the following is NOT a factor that contributes to the increasing popularity of arthroscopic shoulder surgery?
Signup and view all the answers
The passage states that the actual rotator cuff tear most commonly occurs in the ____ muscle and is a primary cause of pain in many adults.
The passage states that the actual rotator cuff tear most commonly occurs in the ____ muscle and is a primary cause of pain in many adults.
Signup and view all the answers
Which of the following muscles is innervated by the axillary nerve, contributing to the stability and rotation of the shoulder joint?
Which of the following muscles is innervated by the axillary nerve, contributing to the stability and rotation of the shoulder joint?
Signup and view all the answers
Traction on the operative arm is frequently applied during shoulder arthroscopy. What is the primary rationale for this technique?
Traction on the operative arm is frequently applied during shoulder arthroscopy. What is the primary rationale for this technique?
Signup and view all the answers
What is the surgical implication of a rotator cuff tear that involves the tendon detaching from the bone?
What is the surgical implication of a rotator cuff tear that involves the tendon detaching from the bone?
Signup and view all the answers
Why is it crucial for the anesthetist to periodically visualize the head and neck during shoulder arthroscopy, particularly while the surgeon is manipulating the shoulder?
Why is it crucial for the anesthetist to periodically visualize the head and neck during shoulder arthroscopy, particularly while the surgeon is manipulating the shoulder?
Signup and view all the answers
Which of the following statements accurately describes the relationship between cerebral perfusion pressure (CPP) and mean arterial pressure (MAP) in the beach chair position during shoulder arthroscopy?
Which of the following statements accurately describes the relationship between cerebral perfusion pressure (CPP) and mean arterial pressure (MAP) in the beach chair position during shoulder arthroscopy?
Signup and view all the answers
Which of the following factors is NOT a direct consequence of the upright position and general anesthesia in a patient undergoing shoulder arthroscopy?
Which of the following factors is NOT a direct consequence of the upright position and general anesthesia in a patient undergoing shoulder arthroscopy?
Signup and view all the answers
Which of the following situations would MOST likely negatively impact cerebral autoregulation during shoulder arthroscopy?
Which of the following situations would MOST likely negatively impact cerebral autoregulation during shoulder arthroscopy?
Signup and view all the answers
Which of the following physiological changes associated with the beach chair position is NOT directly addressed in the passage as a potential concern during shoulder arthroscopy?
Which of the following physiological changes associated with the beach chair position is NOT directly addressed in the passage as a potential concern during shoulder arthroscopy?
Signup and view all the answers
When deliberate hypotension is requested during shoulder arthroscopy, which of the following is the MOST likely rationalization for this practice?
When deliberate hypotension is requested during shoulder arthroscopy, which of the following is the MOST likely rationalization for this practice?
Signup and view all the answers
Why is it essential to avoid significant hypocapnia during shoulder arthroscopy in the beach chair position?
Why is it essential to avoid significant hypocapnia during shoulder arthroscopy in the beach chair position?
Signup and view all the answers
What is the primary justification for the use of vasopressors during shoulder arthroscopy in the beach chair position?
What is the primary justification for the use of vasopressors during shoulder arthroscopy in the beach chair position?
Signup and view all the answers
Why is it important to maintain normocarbia in patients positioned in the beach chair during shoulder arthroscopy?
Why is it important to maintain normocarbia in patients positioned in the beach chair during shoulder arthroscopy?
Signup and view all the answers
Which of the following best describes the rationale for using the external auditory meatus as a landmark for estimating the location of the circle of Willis during shoulder arthroscopy?
Which of the following best describes the rationale for using the external auditory meatus as a landmark for estimating the location of the circle of Willis during shoulder arthroscopy?
Signup and view all the answers
Study Notes
Anesthesia for Shoulder Arthroscopy
- Intercostal blocks provide intraoperative and postoperative pain relief.
- Beach chair positioning reduces brachial plexus injuries compared to lateral decubitus.
- In the beach chair position, arterial blood pressure (BP) readings in the arm don't accurately reflect brain pressure (MAP). Low arm MAP readings during beach chair positioning may not indicate adequate cerebral or coronary perfusion, posing a stroke risk. Measurements or estimates of the MAP can be made once the patient is in the beach chair position. The critical variable is the vertical distance from the circle of Willis to the BP cuff.
- Arthroscopic shoulder surgery is less invasive, allowing for faster patient discharge (within 24 hours).
- Arthroscopic shoulder surgery utilizes fiber optics, smaller instrumentation, and improved techniques for increased popularity.
- A rotator cuff injury affects one or more of the four shoulder muscles (supraspinatus, infraspinatus, teres minor, subscapularis).
- Injuries can be acute (e.g., falls) or chronic.
- Acute injuries can cause hemorrhage and inflammation of the bursa.
- Inflammation reduces space under the acromion, leading to impingement during shoulder abduction, creating a cycle of inflammation and impingement.
- The shoulder joint is supported by the clavicle, scapula, and humerus, along with ligaments.
- The rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) stabilize the humeral head against the scapula, enabling lifting and rotation.
- The rotator cuff forms a covering around the humerus.
- A rotator cuff tear within the supraspinatus muscle is a common cause of shoulder pain in adults.
- The type of surgery depends on tear size and location.
- Tendon tears may require repair with suture via arthroscopy or an open technique.
- Tendon tears away from bone may require direct tendon-to-bone repair.
- Acromion removal may be needed due to impingement.
- Traction on the operative arm is often used to improve surgical conditions.
- Patient head must be protected from pressure and secured with a strap.
- Anesthetist needs to visualize and ensure proper head and neck alignment due to surgical manipulations.
- Surgeons often prefer the beach chair position for rotator cuff repair, improving visualization and minimizing brachial plexus injury.
- Physiologic changes in the upright position include decreased MAP, stroke volume (SV), cardiac output (CO), and PaO2, along with increased alveolar-arterial oxygen gradient, pulmonary, and vascular resistance.
- Systemic vascular resistance (SVR) increases up to 50–80% in awake patients to compensate.
- General anesthetics inhibit this response, leading to vasodilation and decreased cardiac output further compromising cerebral perfusion.
- Cerebral perfusion pressure (CPP) decreases by about 15% in the sitting position, calculated as MAP minus intracranial pressure (ICP) or central venous pressure (CVP)
- General anesthetics cause vasodilation, myocardial depression, and impaired venous return, further impairing cerebral blood flow.
- Inspiratory subatmospheric pressure during spontaneous ventilation increases cerebral venous return; this effect is lost with positive pressure ventilation.
- Flexion of the head can obstruct internal jugular veins, causing cerebral venous engorgement. Head extension impairs cerebral blood flow (CBF), possibly leading to cerebral ischemia.
- Cerebral autoregulation maintains constant blood flow when MAP is between 60 and 160 mmHg.
- Outside this range, CBF becomes pressure-dependent.
- For poorly controlled hypertensive patients, autoregulation is shifted to the right, needing a higher MAP for adequate perfusion.
- Orthopedic surgeons sometimes request deliberate hypotension for shoulder arthroscopy, specifically rotator cuff repair.
- Hypocapnia significantly reduces internal carotid artery and CBF. This change will be exacerbated when the patient is placed in the sitting position. Significant hypocapnia should be avoided to decrease the potential for cerebral hypoperfusion.
- Maintaining normocarbia is important for patients in the beach chair position.
Surgical Procedure Details
- Traction on operative arm improves surgical conditions.
- Patient head protection, secured by Velcro or tape, with ear checks.
- Anesthetist needs to periodically check patient head and neck alignment.
Anesthetic Management and Considerations
Preoperative Period
- Interscalene block consent is discussed.
- Patient information includes risks, benefits, anesthetic procedure expectations.
- Thorough patient history and medication list are gathered.
- Rotator cuff innervation involves the cervical plexus, dividing into roots, trunks, divisions, cords, and branches.
- Supraspinatus and infraspinatus innervated by the suprascapular nerve.
- Teres minor innervated by the axillary nerve.
- Subscapularis innervated by the subscapular nerve.
- Emergency airway and resuscitation equipment are checked prior to regional anesthetic.
- Aseptic technique is essential.
Intraoperative Period
- Hypotension during beach chair arthroscopy should be aggressively treated. This includes vigilant monitoring, titration of anesthetic gases, gradual position changes, IV fluid administration, and vasopressors as needed.
Inter-Scalene Block Placement
- Patient positioned supine, head facing opposite the anesthetized shoulder.
- Patient slightly elevates head to see the sternocleidomastoid muscle's clavicular head.
- Palpating finger placed behind sternocleidomastoid muscle, patient relaxes head lift.
- Palpate the interscalene groove between anterior and middle scalene muscles.
- Injection site is at C6 (cricoid level), guided by ultrasound.
- Incremental local anesthetic injection; aspirate continually to avoid intravascular injection.
- This method minimizes local anesthetic systemic toxicity (LAST).
- LAST symptoms initially include lightheadedness, tinnitus or metal taste; progressing to seizures, loss of consciousness, and respiratory arrest.
- Cardiovascular LAST sign is bradycardia, then asystole.
- Prevention and intralipid infusion are treatments for LAST.
Postoperative Period
- Respiratory depression can occur due to increased opioids during surgery. The anesthetist must be aware of possible postoperative respiratory depression because analgesia from the interscalene block results in decreased postoperative pain.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers essential anesthesia techniques for shoulder arthroscopy. Key topics include intercostal blocks for pain relief, positioning techniques, and implications for blood pressure readings. Enhance your understanding of the risks and benefits associated with different positioning strategies during surgery.
