Anesthesiology APPLIED Exam › Regional anesthesia and acute pain

Thoracic epidural analgesia

T1Regional anesthesia and acute pain·728 words · ~4 min read·v0.1DRAFT

Why examiners ask this

Thoracic epidural analgesia remains the reference standard for thoracotomy and upper abdominal surgery, but it competes with paravertebral and fascial plane blocks and is limited by anticoagulation and hypotension. The examiner tests application of knowledge about segmental physiology, judgment about choosing an epidural over an alternative, and adaptability when the epidural causes hypotension in an under-filled thoracic patient or fails on postoperative day 1.

The 60-second answer

For a thoracotomy I offer a thoracic epidural when there is no contraindication, because it reduces pain, pulmonary complications and opioid use. I check anticoagulants against ASRA intervals and get consent. I place it awake or lightly sedated at T5–T7, near the dermatomal center of the incision, by a paramedian approach because the spinous processes are steeply angled. I test the catheter and dose it before incision, then run a dilute infusion of bupivacaine 0.1% with hydromorphone 10 mcg/mL at about 6 mL/h with patient-controlled boluses. I watch for hypotension, especially under one-lung ventilation and with restrictive fluid plans, and I check the block twice daily. If the patient is anticoagulated or the epidural fails, I use a paravertebral catheter or erector spinae block.

Decision points and the "why"

Paravertebral is a near-equal alternative — similar analgesia for thoracotomy with less hypotension, urinary retention and fewer anticoagulation constraints. For video-assisted surgery I usually prefer a paravertebral or erector spinae block over an epidural.
Placement level — mid-thoracic placement covers the incision with less drug and preserves lower-limb strength and bladder function better than a lumbar catheter.
Awake placement — the cord is directly beneath the needle; an awake patient reports paresthesia. I accept placement under general anesthesia in children and in adults who cannot cooperate.
Hypotension — a high thoracic block blocks cardiac accelerator fibers and splanchnic tone. I treat with a vasopressor rather than fluid, because thoracic surgeons want restriction to avoid post-pneumonectomy pulmonary edema.
Opioid in the epidural — hydrophilic hydromorphone spreads over more segments and improves analgesia; it carries delayed respiratory depression, so I avoid parenteral opioids alongside it.
Benefits — improved FEV1 and cough, earlier mobilization, and reduced pulmonary complications; it also reduces the risk of chronic post-thoracotomy pain.

The complication they will inject

After a right thoracotomy, the patient in recovery has pain 9/10 on the left side of the incision and a blood pressure of 85/50. I examine the block with ice: it covers T4–T8 on the right only, a unilateral block, and the pressure is low because the epidural is working on one side. I give a vasopressor and check for bleeding, because a falling pressure after thoracotomy is hemorrhage until proven otherwise. For the block, I withdraw the catheter 1–2 cm and give a 4–5 mL bolus with the painful side down. If that fails, I replace it or switch to a paravertebral catheter, rather than accept a poorly controlled patient who cannot cough.

Pitfalls that cost points

Treating epidural hypotension with liters of crystalloid in a lung resection patient.
Forgetting anticoagulation timing for placement and removal.
Not considering paravertebral or erector spinae as alternatives.
Assuming hypotension after thoracotomy is the epidural without excluding bleeding.
Continuing an ineffective epidural without testing and correcting it.

Rapid-why

Q: Why paramedian at mid-thoracic levels? A: The spinous processes angle steeply caudad, so a midline approach is difficult; paramedian access to the interlaminar space is easier.

Q: Why does a thoracic epidural reduce pulmonary complications? A: Better analgesia improves deep breathing and coughing and reduces splinting, with less opioid-related sedation.

Q: Why is post-pneumonectomy pulmonary edema relevant? A: It is linked to positive fluid balance; the epidural tempts fluid boluses that must be avoided.

Q: What does a high block do to the heart? A: Blocking T1–T4 causes bradycardia and reduced contractility; it also reduces myocardial oxygen demand.

Numbers to know

Item	Value
Thoracotomy level	T5–T7
Infusion	Bupivacaine 0.1% + hydromorphone 10 mcg/mL at 4–8 mL/h
Thoracic dosing	~1 mL per segment
Test dose	Lidocaine 1.5% 3 mL with epinephrine 1:200,000
Cardiac accelerators	T1–T4

Sources

Sources have not been attached to this page yet.