What is the recommended dose of sugammadex (Bridion) for reversing neuromuscular blockade in an obese patient with potential Impaired renal function?

Sugammadex Dosing in Obese Patients with Renal Impairment

For obese patients with potential renal impairment, dose sugammadex based on ideal body weight (IBW) plus 40% (corrected body weight), using 2 mg/kg for moderate blockade or 4 mg/kg for deep blockade, with mandatory quantitative neuromuscular monitoring and prolonged observation for recurarization. 1

Weight-Based Dosing Strategy

The recommended dosing approach uses corrected body weight (IBW + 40%) rather than actual body weight, as sugammadex is a water-soluble drug that distributes in lean mass and extracellular volumes, not adipose tissue. 2, 1

Calculating the Appropriate Weight

• Calculate ideal body weight: height in cm minus 110 for women, height in cm minus 100 for men 1
• Add 40% to the IBW to determine corrected body weight for dosing 1
• The European Society of Anaesthesiology specifically recommends this IBW + 40% approach for obese patients 2, 1

Dose Based on Depth of Neuromuscular Blockade

The specific sugammadex dose depends entirely on the depth of blockade at time of reversal:

Moderate Blockade (2 TOF Responses Present)

• Administer 2 mg/kg based on IBW + 40% 1
• Expected recovery to TOF ratio ≥0.9 in approximately 2-5 minutes 1
• Clinical studies confirm this dosing achieves complete reversal in morbidly obese patients without residual paralysis 3

Deep Blockade (1-2 PTC Responses, No TOF)

• Administer 4 mg/kg based on IBW + 40% 1
• Expected recovery in just over 4 minutes 1
• This dose provides 93% success rate for reversal within 10 minutes in morbidly obese patients 4

Immediate Reversal After High-Dose Rocuronium

• Administer 8 mg/kg based on actual body weight (exception to the IBW + 40% rule) 1
• This applies only for rocuronium, not vecuronium 5

Critical Renal Impairment Considerations

In patients with severe renal failure (CrCl <30 mL/min), sugammadex efficacy is decreased and requires extended monitoring. 1

Pharmacokinetic Changes in Renal Impairment

• Sugammadex half-life increases from 2 hours (normal function) to 19 hours in severe renal impairment 5
• Overall exposure increases 5-fold in severe renal impairment and 2-fold in moderate impairment 5
• Low concentrations remain detectable for at least 48 hours post-dose in severe renal impairment 5

Waiting Times for Re-dosing NMBAs

• In mild or moderate renal impairment, wait 24 hours before re-administering 0.6 mg/kg rocuronium or 0.1 mg/kg vecuronium after reversal with up to 4 mg/kg sugammadex 5
• If shorter waiting time required, use 1.2 mg/kg rocuronium 5
• After 16 mg/kg sugammadex dose, wait 24 hours regardless of renal function 5

Mandatory Neuromuscular Monitoring Requirements

Quantitative neuromuscular monitoring is absolutely mandatory using acceleromyography or electromyography at the adductor pollicis. 1

Pre-Administration Assessment

• Assess TOF ratio and post-tetanic count (PTC) before administering sugammadex to determine appropriate dose 1
• Monitoring determines whether moderate (2 TOF) or deep (1-2 PTC) blockade is present 1

Post-Administration Monitoring

• Continue monitoring after sugammadex administration to detect potential recurarization 1
• Ventilatory support is mandatory until adequate spontaneous respiration is restored and airway patency is assured 5
• Even with complete reversal, other perioperative drugs may depress respiratory function 5

Key Clinical Pitfalls to Avoid

Risk of Recurarization

• Using lower than recommended doses significantly increases risk of recurrence of neuromuscular blockade 5
• Recurarization may occur due to displacement of rocuronium/vecuronium from sugammadex by other drugs 5
• The highest risk period for displacement reactions is 3 times the half-life of sugammadex (approximately 6 hours in normal renal function, much longer with renal impairment) 5

Bradycardia Risk

• Marked bradycardia, including cardiac arrest, has occurred within minutes of sugammadex administration 5
• Monitor hemodynamic changes closely during and after reversal 5
• Have atropine immediately available for clinically significant bradycardia 5

Anaphylaxis Considerations

• Anaphylaxis has been reported, including at doses less than 16 mg/kg 5
• Most common features include dermatologic symptoms (urticaria, rash, flushing) and hypotension requiring vasopressor support 5
• Some cases required prolonged intubation or re-intubation 5

Advantages Over Neostigmine in Obesity

Sugammadex is strongly preferred over neostigmine in obese patients because neostigmine dosed on actual body weight causes prolonged recovery time. 1 Clinical trials demonstrate sugammadex provides 9-fold faster recovery compared to neostigmine in morbidly obese patients. 6