Anesthesiology APPLIED Exam › Neuroanesthesia and neuromuscular

Neuromuscular blockade, monitoring and reversal

Neuroanesthesia and neuromuscular·~5 min read· Physician-reviewed✓ Sourced · 5

Stem

A 66-year-old man, 84 kg, with COPD, is having a robotic prostatectomy under sevoflurane. He received rocuronium 0.6 mg/kg at induction and two further doses at the surgeon's request, the last 25 minutes ago. The surgeon has just started closing the port sites. On the acceleromyograph at the thumb there are no twitches to train-of-four stimulation and a post-tetanic count of 2.

Question

How will you reverse his blockade and decide that he is ready for extubation?

Ideal answer

HeadlineDeep block, post-tetanic count 2: neostigmine cannot reverse him. Sugammadex 4 mg/kg, about 340 mg, extubating only at a measured TOF ratio of at least 0.9.¹

Quantitative monitoring from induction to extubation, at the thumb, not the eye, because the face recovers early and overestimates recovery.
Neostigmine only for minimal block: 0.03–0.07 mg/kg, maximum 5 mg, with glycopyrrolate,² at a measured ratio of at least 0.4.¹
Temperature checked, because hypothermia, volatile agent and acidosis all prolong block.
The number decides, not the head lift: ratio 0.9 on the monitor, then commands followed and a sustained head lift. With his COPD, residual weakness means aspiration, hypoxemia and reintubation.
Ratio stalls below 0.9: more sugammadex, rather than extubating a borderline patient.

Breaking down the answer

Quantitative over qualitative — a clinician feeling the thumb cannot detect fade above a ratio of about 0.4, so a nerve stimulator alone misses the band where aspiration and hypoxemia occur. The 2023 ASA guideline recommends quantitative over qualitative monitoring and against clinical assessment alone.¹
State the plan — a candidate who cannot state a monitoring plan in one sentence looks unsafe.
The adductor pollicis, not the orbicularis oculi — the eye recovers before the diaphragm and the thumb. The face can time intubation, because the laryngeal muscles track it, but the guideline recommends against eye muscles, so I switch before reversal.¹
Sugammadex over neostigmine — encapsulating rocuronium and vecuronium, it reverses any depth in about 3 minutes; neostigmine generally reaches 0.9 in 10–20 minutes.² The guideline: sugammadex at deep, moderate and shallow depths, neostigmine a reasonable alternative at minimal depth (0.4 to 0.9).¹
Dose to the measured depth — 2 mg/kg at two twitches, 4 mg/kg at a post-tetanic count of 1–2, 16 mg/kg for immediate reversal after rocuronium 1.2 mg/kg;³ under-dosing produces recurarization.
Renal failure changes the drug, not the plan — rocuronium and vecuronium accumulate, so I use cisatracurium (Hofmann elimination) and still monitor to 0.9. Sugammadex is not recommended below a creatinine clearance of 30 mL/min;³ neostigmine is my reversal there.
Succinylcholine — 1–1.5 mg/kg lasts 5–10 minutes; I avoid it after the acute phase of burns, trauma and denervation, in prolonged immobility and in myopathies because of hyperkalemia; phase II block after large or repeated doses looks non-depolarizing.⁴

Follow-up question

In the PACU 20 minutes later he is uncoordinated and tachypneic, and his saturation falls to 88%. What do you do?

Follow-up answer

HeadlineResidual block until proven otherwise; I tell the PACU nurse that is what I am treating.

Bag-mask support, sit him up, 100% oxygen, the quantitative monitor back on. He already had sugammadex, so if the ratio is below 0.9 I give more, because recurarization after an inadequate dose is the usual cause; had he received neostigmine, I would give sugammadex 2–4 mg/kg. I check temperature, potassium, magnesium and acid-base, and look for other causes: opioids, a missed myasthenic history. If he cannot protect his airway, I reintubate and reverse at leisure rather than gamble on a borderline patient who is aspirating, then reassess with the monitor before the next attempt.

Pitfalls that cost points

Saying "I would reverse with neostigmine" without stating the twitch count you require first.
Quoting a train-of-four ratio of 0.7 as adequate; the standard is 0.9 and the guideline is explicit.
Offering head lift or grip as proof of reversal; they are insensitive and only supplement the monitor.¹
Forgetting that neostigmine given at full recovery causes paradoxical weakness.

Rapid-fire

Q: Unexpected reintubation after sugammadex: what relaxant? A: A usual rocuronium dose has delayed onset and short duration: 1.2 mg/kg or a different class, and after 16 mg/kg a 24-hour wait is suggested.³

Q: What else prolongs block? A: Volatile agents, magnesium, aminoglycosides, hypothermia, acidosis and hypokalemia.

Q: Why does fade occur with non-depolarizers but not with succinylcholine? A: Non-depolarizers block presynaptic nicotinic receptors that mobilize acetylcholine during repeated stimulation; succinylcholine does not, so phase I block shows equal twitches.

Q: Why give glycopyrrolate with neostigmine? A: Neostigmine raises acetylcholine at muscarinic receptors too, causing bradycardia, bronchospasm and secretions; glycopyrrolate matches its onset better than atropine.

Q: Can sugammadex reverse succinylcholine or cisatracurium? A: No. It binds only the steroidal relaxants rocuronium and vecuronium; benzylisoquinoliniums need neostigmine or time.

Q: What happens to hormonal contraception after sugammadex? A: It binds progesterone; I counsel a non-hormonal backup for 7 days.³

Numbers to know

Item	Value
Rocuronium intubating / RSI dose	0.6 mg/kg / 1.2 mg/kg⁵
Succinylcholine	1–1.5 mg/kg IV; 3–4 mg/kg IM, max 150 mg⁴
Sugammadex	2 mg/kg at TOF 2; 4 mg/kg at PTC 1–2; 16 mg/kg immediate³
Neostigmine	0.03–0.07 mg/kg, max 5 mg,² with glycopyrrolate 0.01 mg/kg
Extubation threshold	TOF ratio ≥0.9, measured quantitatively¹
Cisatracurium	0.15–0.2 mg/kg, Hofmann elimination

Sources

1.New Practice Guidelines for Neuromuscular Blockade · APSF, 2023 · apsf.orgReproduces the recommendations of the 2023 ASA Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade; the Anesthesiology full text was not reachable.
2.BLOXIVERZ (neostigmine methylsulfate injection) prescribing information · FDA, 2015 · accessdata.fda.gov
3.BRIDION (sugammadex) injection prescribing information · FDA / DailyMed · dailymed.nlm.nih.gov
4.QUELICIN (succinylcholine chloride) injection prescribing information · FDA / DailyMed · dailymed.nlm.nih.gov
5.Rocuronium bromide injection prescribing information · FDA / DailyMed · dailymed.nlm.nih.gov

Facts on this page were checked against these sources on Oct 14, 2026. Guidelines change; confirm doses against current institutional protocols.