UBP 2.3 (Short Form): Orthopedics – Shoulder Surgery/Beach Chair

Question 1

Is an ambulatory surgery center an appropriate setting for this patient?

(— See Notes in UBP Prep Binder — Has Xtra Questions.. and other ways to answer this question —)

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 1

I would proceed with the case only if I believed her risk for OSA was low, or if I believed she likely had OSA, but the facility resources were appropriate, her comorbidites were adequately optimized, and her post-operative pain could be managed predominantly using nonopioid analgesic techniques (i.e. interscalene block, NSAIDs, etc.).

My concern in allowing the procedure to be performed in an ambulatory center is related to her obesity and history of loud snoring, both of which are consistent with undiagnosed obstructive sleep apnea (OSA).

Moreover, in the setting of OSA, her post-operative management would be further complicated by her history of difficult airway management and the possibility that she will require significant narcotic administration to control post-operative pain (rotator cuff repair).

Therefore, I would:

1. attempt to determine her risk for, and the severity of, any OSA by performing a physical exam (e.g. BMI, neck circumference, tongue mass, size of the tonsils, and abnormalities affecting the airway);
2. determine the extent and severity of her diabetes and any other coexisting disease (e.g. hypertension, stroke, myocardial infarction, and other cardiovascular problems);
3. determine whether an interscalene block could be utilized to reduce intra-operative and post-operative anesthetic requirements (e.g. do the patient and surgeon agree to the procedure; has the patient’s smoking led to severe COPD, making temporary unilateral diaphragmatic paralysis unacceptable);
4. evaluate the facility capabilities to decide if they were appropriate for the management of a patient with OSA (i.e. emergency airway and respiratory care equipment, laboratory and radiology capabilities or access, transfer agreement with an inpatient facility); and
5. assess the adequacy of post-discharge observation.

Clinical Notes:

• Considerations when deciding between inpatient and outpatient management include:
  
  1. the severity of obstructive sleep apnea,
  2. the presence of any anatomical and/or physiological abnormalities,
  3. the presence and status of coexisting disease,
  4. the nature of the surgery,
  5. the type of anesthesia required,
  6. the anticipated post-operative opioid requirements,
  7. the patient’s age,
  8. the adequacy of post-discharge observation, and
  9. the capabilities of the outpatient facility (e.g. emergency airway equipment, respiratory care equipment, radiology facilities, clinical laboratory facilities, and a transfer agreement with an inpatient facility).
• The STOP-BANG screening tool helps to identify the risk of undiagnosed OSA
  
  • Snoring - louder than talking or loud enough to be heard through a closed door
  • Tiredness (daytime)
  • Observed apnea - witnessed apnea during sleep
  • Pressure - high blood pressure
  • BMI > 35 kg/m²
  • Age > 50 years
  • Neck circumference > 40 cm
  • Gender (Male)
• The presence of < 3 of these criteria is associated with a low risk of OSA, while the presence of 3 or more is associated with a high risk of OSA.
• Furthermore, the presence of 5-8 of these criteria is associated with a high probability of moderate-to-severe OSA.
• According to the 2006 ASA Practice Guidelines for the Perioperative Management of Patients with OSA, consultants were equivocal as to whether the following patients at increased perioperative risk from OSA could safely undergo outpatient surgery:
  
  1. Patients undergoing superficial procedures under general anesthesia; or
  2. Children over 3 years of age undergoing tonsillectomy.
• The consultants did NOT believe the following patients at increased perioperative risk from OSA could safely undergo outpatient surgery:
  
  1. Those undergoing airway surgery (i.e. uvulopalatopharyngoplasty); or
  2. Children under 3 years of age undergoing tonsillectomy.
• The updated 2014 guidelines do NOT specifically adress these patients populations.

Own Notes from UBP Videos – Score > 5 → may indicate a patient not appropriate for outpatient surgery.

Question 2

You know that the surgeon prefers the beach chair position for this type of surgery. Knowing this, are you concerned about the patient’s blood pressure?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 2

I am concerned due to the increased risk for cerebral ischemia associated with placing a patient under general anesthesia in the beach chair position.

This is even more concerning since this patient with diabetes, GERD, resting tachycardia, and an elevated preoperative blood pressure may suffer from undiagnosed chronic hypertension (BP = 168/98 mmHg) and/or autonomic neuropathy.

The rightward shifting of the cerebral autoregulation curve (requiring higher than normal pressures for adequate cerebral perfusion) and the impairment of normal autonomic responses by general anesthesia and diabetic neuropathy would potentially compromise this patient’s ability to maintain adequate cerebral perfusion when placed in the beach chair position.

Therefore, I would attempt to identify, by history and physical, the signs and symptoms of chronic hypertension and/or autonomic neuropathy.

Moreover, I would be very vigilant in maintaining adequate end-organ perfusion throughout the case.

Question 3

You see the patient 2 days prior to surgery for a pre-operative interview.

Would you recommend she stop smoking before her surgery?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 3

I would recommend she stop smoking because even 2 days of smoking cessation can reduce carboxyhemoglobin levels, abolish nicotine’s stimulatory effects on the cardiovascular system, and improve mucous clearance.

However, the evidence suggests that the risk of post-op pulmonary complications does not begin to decrease until 4 weeks of smoking cessation;

the risk approaches that of nonsmokers with 8 weeks of cessation.

Additionally, there are some that believe the increased mucous clearance can actually worsen airway conditions in the first several days following cessation.

Despite this, a preoperative recommendation to stop smoking could potentially lead to long-term cessation, a benefit that I believe far outweighs any concerns of increased mucous secretion.

Question 4

The surgeon requests that the case be done with just an interscalene block. Would you agree?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 4

For a patient who potentially suffers from obstructive sleep apnea, autonomic neuropathy, and GERD, the use of regional anesthesia, would potentially be beneficial in reducing the risk of respiratory depression, end-organ ischemia (cardiac and cerebral), and aspiration.

However, for this patient with a known difficult airway, I would be concerned that an inability to tolerate the procedure due to anxiety or inadequate regional analgesia could lead to the necessity for sedation or general anesthesia under less than optimal conditions.

Therefore, keeping her preference in mind, I would consider proceeding under regional anesthesia if I believed she would tolerate both being awake during the procedure and the one-sided phrenic nerve paralysis often associated with an interscalene block (this long-term smoker is at increased risk for significant pulmonary disease).

Moreover, I would only proceed with the understanding that, should her block prove inadequate, the plan would be to perform an awake intubation.

FInally, given the potential for complications associated with block placement, (i.e. seizure or high spinal anesthesia), inadequate intra-operative analgesia, and patient intolerance of the procedure, I would – provide aspiration prophylaxis (increased risk secondary to GERD and the gastroparesis sometimes associated with obesity and/or autonomic neuropathy) and ensure the immediate availability of difficult airway equipment.

Question 5

What is the Bezold-Jarisch reflex?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 5

The Bezold-Jarisch reflex results when stimulation of inhibitory cardiac receptors by stretch, chemical substances, or drugs leads to increased parasympathetic activity and inhibited sympathetic activity, with subsequent bradycardia, vasodilation, and hypotension.

In the setting of shoulder surgery for an awake patient with interscalene blockade, it is postulated that increased levels of circulating epinephrine (from the local anesthetic or irrigation solution) along with decreased venous return (venous pooling in the sitting position) leads to stimulation of these same receptors, with subsequent bradycardia, hypotension, and syncope potentially leading to cardiac arrest.

Question 6

How would you evaluate this patient, preoperatively?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 6

My preoperative evaluation would focus on her known or suspected comorbidites.

1. Considering her long-term smoking history and shortness of breath with normal activity, I would attempt to identify any significant pulmonary disease by history and physical (i.e. cough, sputum production, frequent pulmonary infections, etc.); possibly ordering PFTs, a chest x-ray, and/or ABGs as indicated.
2. Given her obesity (likely sedentary lifestyle), diabetes (possible autonomic neuropathy and silent ischemia), shortness of breath, and suspected OSA and/or hypertension, I would assess her functional capacity (i.e. METs) and attempt to identify any additional signs or symptoms of cardiac disease through a focused history (i.e. unstable and/or severe angina, previous cardiac testing, decompensated heart failure, arrhythmias, any myocardial infarction), physical exam (i.e. jugular venous distension, hepatomegaly, peripheral edema, and pulmonary edema), and recent ECG (Class IIB recommendation when there is one clinical risk factor – i.e. diabetes – and the patient is undergoing intermediate risk surgery).
3. Considering her history of diabetes, I would order a serum glucose and review all available lab work that would serve to identify any end organ disease associated with poorly controlled diabetes (i.e. complete blood count, blood urea nitrogen, creatinine, potassium, and urinalysis).
4. In the light of her history of difficult airway management, I would perform a thorough airway exam, including mouth opening, thyromental distance, neck range of motion, etc.
5. Recognizing that her diabetes, hypertension, resting tachycardia, GERD, and exercise tolerance (she experiences SOB with normal activity) are all associated with autonomic neuropathy, I would attempt to identify any additional signs and symptoms that are associated with this condition through a focused history and physical exam, such as early satiety, bloating, or postural hypotension.
6. Given my concerns that she may have undiagnosed obstructive sleep apnea, I would review any pertinent history and employ the STOP-BANG criteria, which includes snoring, tiredness (daytime somnolence), observed apnea (during sleep), high blood pressure, BMI > 35 kg/m2, age > 50 years, neck circumference > 40 cm, and male gender, to assess her risk of having undiagnosed OSA.
7. Finally, I would assess the severity and effectiveness of her treatment, in regards to her gastroesophageal reflux disease.

Question 7

How would you evaluate this patient for the presence of autonomic neuropathy?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 7

She already exhibits several clinical conditions that are consistent with autonomic neuropathy, such as diabetes, hypertension, resting tachycardia, GERD, and exercise intolerance (she experiences SOB with normal activity).

Therefore, I would begin by attempting to identify any additional signs and symptoms that would be consistent with this diagnosis, such as early satiety, prolonged postprandial fullness, bloating, postural hypotension, lack of sweating, painless myocardial ischemia, peripheral neuropathy, dysrhythmias, nocturnal diarrhea, nausea, vomiting, and epigastric pain (impotence may occur in male patients).

I would also consider having the patient’s autonomic nervous system evaluated through a series of noninvasive tests.

Diabetic autonomic neuropathy often affects the parasympathetic system first, which can be assessed by measuring the heart rate response to performing a valsalva maneuver, moving from the supine to standing position, and/or taking six deep breaths over 1 minutes.

In more severe disease the sympathetic system is affected, which can be assessed by measuring the patient’s blood pressure response to sustained handgrip and moving from the supine to standing position.

Question 8

After further evaluation it becomes clear that the patient is suffering from significant autonomic neuropathy.

What are your anesthetic concerns?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 8

My anesthetic concerns in taking care of a patient with significant autonomic neuropathy would include:

1. an increased risk for aspiration, secondary to gastroparesis (particularly suspected in patients experiencing nausea, vomiting, early satiety, bloating, prolonged postprandial fullness, and epigastric pain);
2. an increased risk for significant hypotension (especially during induction), secondary to impaired peripheral vasoconstriction and baroreceptor function;
3. the high incidence of silent ischemia associated with significant autonomic neuropathy;
4. an increased risk for intraoperative hypothermia, probably due to impaired peripheral vasoconstriction;
5. an impaired ventilatory response to hypoxia and hypercapnia, making her more susceptible to drug-induced respiratory depression during recovery (this is especially concerning in a patient with suspected OSA); and
6. the potential for sudden cardiorespiratory arrest, possibly secondary to anesthetic or analgesic-induced interference with respiration or sinus automaticity.

In order to reduce these risks, I would take full-stomach precautions, employ warming measures to maintain normothermia, utilize etomidate for induction (if general anesthesia was necessary), and provide continuous cardiac and respiratory monitoring for 24-72 hours post-operatively.

Question 9

Would you start her on a B-blocker, preoperatively, to treat her blood pressure?

(A 46-year-old, 97 kg, 5’2” female is scheduled for surgery at an ambulatory surgery center to repair her left rotator cuff. Her surgical history includes a right mastectomy, during which the anesthesiologist “had some trouble getting the tube in”. She has been smoking for 29 years and gets short of breath with normal activity. Furthermore, she has severe gastroesophageal reflux disease, is an insulin dependent diabetic, and admits to loud snoring. Vital signs: P = 108; BP = 168/98 mmHg; R = 12; T = 36ºC.)

Answer 9

The careful titration of B-blockers to control heart rate and blood pressure is of unknown benefit in patients undergoing intermediate-risk surgery (i.e. orthopedic surgery) who have a single cardiac risk factor (i.e. diabetes mellitus) in the absence of known coronary artery disease (2009 ACCF/AHA Class IIb recommendation).

Moreover, I would not attempt to acutely initiate B-blocker therapy on the day of surgery (the 2014 ACC/AHA guidelines recommend that the initiation of B-blocker therapy should occur 2-7 days prior to surgery), recognizing that this is associated with an increased risk of bradycardia, hypotension, stroke, and total mortality (although cardiovascular morbidity and mortality is reduced).

The risk of stroke would be even more concerning in this situation, where the patient is already at increased risk for cerebral hypoperfusion and stroke due to beach-chair positioning during the procedure.

Clinical Notes:

• The 2014 ACC/AHA Guidelines state that it may be reasonable to initiate perioperative B-blocker therapy (2-7 days preoperatively) in patients with –
  
  1. three or more risk factors (e.g. diabetes, HF, CAD, renal insufficiency, cerebrovascular accident) identified using the revised cardiac risk index (Class IIB) or
  2. intermediate- or high-risk myocardial ischemia identified by preoperative risk stratification tests (Class IIB).
• In patient in whom beta blocker therapy is initiated, it may be reasonable to begin perioperative beta blockers long enough in advance to assess safety and tolerability, preferably more than 1 day before surgery (Class IIB).
  
  • Beginning beta blockers = 1 day before surgery is at a minimum ineffective and may in fact be harmful.
  • Starting the medication 2-7 days before surgery may be preferred.
  • The clinical assessment for tolerability is a key element of preoperative strategies
• Beta-blocker therapy should NOT be started on the day of surgery (Class III: Harm).
  
  • Beta blocker therapy should NOT be started on the day of surgery in beta-blocker naive patients, particularly…
    
    1. At high initial doses
    2. In long-acting form
    3. If there are no plans for dose titration or monitoring for adverse events