Extra Topic 6.8 -- Interscalene Block & Tourniquet Use

Question 1

The surgeon requests that the procedure proceed with an interscalene block. Would you agree?

(A 52-year-old male presents for debridement and repair of injuries to his right elbow and forearm sustained in a bar fight a couple hours earlier. He admits to a 34-year smoking history.)

Answer 1

Assuming this patient who was recently in a bar fight would tolerate undergoing the procedure under regional anesthesia (i.e. not intoxicated or combative), and that his long-term tobacco use had not resulted in significant pulmonary disease (may not tolerate hemidiaphragmatic paralysis),

I would consider an interscalene block for this procedure.

However, since the surgical procedure involves the forearm, an axillary block or supraclavicular block may be more appropriate

considering the ulnar nerve sparing that is often associated with an interscalene block (the C8-T1 nerve roots, which form the ulnar nerve, are spared with an interscalene block up to 50% of the time).

Therefore, if the surgeon and patient preferred and interscalene block for this procedure, I would let them know that the ulnar nerve may need to be blocked with a separate injection.

Question 2

You place an interscalene block for the procedure.

What are the complications associated with this type of block?

(A 52-year-old male presents for debridement and repair of injuries to his right elbow and forearm sustained in a bar fight a couple hours earlier. He admits to a 34-year smoking history.)

Answer 2

The close proximity of several neurovascular structures leads to a number of potential complications associated with interscalene blocks, such as:

1. ipsilateral diaphragmatic paralysis, which occurs 100% of the time and may not be tolerated by those with severe pulmonary disease (results in a 25% reduction in pulmonary function);
2. Horner’s syndrome, consisting of myosis, ptosis, and anhidrosis (results with stellate ganglion blockade);
3. local anesthetic toxicity, secondary to injection into vertebral artery, carotid artery, or jugular vein (as little as 33 cc’s injected into the vertebral artery can result in seizure);
4. pneumothorax, due to the proximity of the cupola of the lung (especially on the right);
5. neuraxial blockade (i.e. epidural or spinal anesthesia), secondary to injection of local anesthetic into the dural sleeve of a nerve root;
6. nerve injury, secondary to intraneural injection of local anesthetic;
7. hematoma formation (especially with puncture of the carotid artery); and, in the case of shoulder surgery in the sitting position,
8. severe hypotension and bradycardia, which may result when decreased venous return to the heart leads to reduced sympathetic tone and enhanced parasympathetic output (Bezold-Jarisch reflex).

Question 3

The surgeon wants to use a tourniquet.

What are the complications associated with tourniquet use?

(A 52-year-old male presents for debridement and repair of injuries to his right elbow and forearm sustained in a bar fight a couple hours earlier. He admits to a 34-year smoking history.)

Answer 3

There are a number of complications associated with prolonged tourniquet use,

1. dull achy pain, tachycardia, and hypertension;
2. muscle damage, occurring beneath the tourniquet at 2 hours (direct pressure), and distal to the tourniquet at 4 hours (muscular ischemia, edema, and microvascular congestion);
3. nerve injury, occurring secondary to direct pressure under the cuff (some sources say ischemia contributes);
4. thrombotic embolism, occurring with tourniquet release;
5. vascular injury, most commonly in patients with peripheral vascular disease;
6. undesirable drug effects (inadequate antibiotic tissue concentrations when given after tourniquet inflation; tissue sequestration of drugs administered prior to inflation, followed by release and subsequent effect following deflation; and reduced volume of distribution for drugs administered following inflation);
7. transient metabolic acidosis, occurring with deflation and the washout of accumulated metabolic waste products in the ischemic extremity; and
8. skin damage, such as pressure necrosis, friction burns, and chemical burns (the latter resulting from antiseptic skin preparation solutions becoming trapped under the cuff and compressed against the skin).

Question 4

An hour into the procedure, the patient begins to complain of pain at the site of the tourniquet despite adequate surgical analgesia.

What do you think?

(A 52-year-old male presents for debridement and repair of injuries to his right elbow and forearm sustained in a bar fight a couple hours earlier. He admits to a 34-year smoking history.)

Answer 4

While the exact mechanism of tourniquet pain is unknown, it is believed that pain transmission through unmyelineated C-fibers occur with the recession of local anesthetic blockade.

The pain, which occurs despite adequate surgical analgesia, is often described as a dull ache or burning sensation, begins around 45-60 minutes following tourniquet inflation, and is associated with tachycardia and hypertension.

This patient, however, may be experiencing pain secondary to inadequate analgesia of the medial brachial cutaneous and intercostobrachial nerves supplying cutaneous innervation to the medial aspect of the upper arm, since these nerves are spared with an interscalene block.

Question 5

An hour into the procedure, the patient begins to complain of pain at the site of the tourniquet despite adequate surgical analgesia.

What would you do?

(A 52-year-old male presents for debridement and repair of injuries to his right elbow and forearm sustained in a bar fight a couple hours earlier. He admits to a 34-year smoking history.)

Answer 5

Recognizing that the definitive treatment for tourniquet pain is to release the tourniquet,

I would ask the surgeon to allow deflation as soon as possible.

In the meantime, I would provide small doses of an opioid and midazolam to ease his discomfort, with the goal of maintaining adequate airway reflexes in this patient who was recently at a bar and is likely at risk for aspiration (i.e. alcohol, food, etc.).

If this was inadequate and tourniquet deflation was still required, I would consider employing general anesthesia by performing a rapid sequence induction with cricoid pressure.

Question 6

The following day, the patient is complaining that his pinky finger is still numb.

He asks if something went wrong with the block in his neck.

What would you say?

(A 52-year-old male presents for debridement and repair of injuries to his right elbow and forearm sustained in a bar fight a couple hours earlier. He admits to a 34-year smoking history.)

Answer 6

I would explain to him that, while it is possible that the residual numbness in his pinky finger is due to nerve damage incurred during the interscalene block (or separate ulnar nerve block),

it is more likely the result of multiple contributing factors, such as –

• positioning,
• inadequate padding at the elbow, and
• direct pressure on the ulnar nerve from the pneumatic tourniquet.

I would also reassure him that this type of injury usually resolves quickly (< 1 week).

However, I would let him know that if his symptoms persisted beyond a week, he should ask his surgeon or a primary care physician to arrange for an appointment with a neurologist.