Functional Respiratory Imaging After Neostigmine or Sugammadex

Study Overview
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Brief Summary
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The use of neuromuscular blocking agents (NMBAs) is still associated with postoperative pulmonary complications. The investigators rely on acceleromyography (AMG) of a peripheral nerve/muscle to assess the patients' breathing capability at the end of surgery. It is possible that respiratory complications after surgery (e.g. desaturation and atelectasis) are related to the lack of diaphragm activity. A previous trial by our study group links the use of sugammadex, a novel selective relaxant binding agent (SRBA) for reversal of neuromuscular blockade, to an increase in diaphragm electrical activity, compared to reversal with neostigmine. Our hypothesis is that by making nicotinergic acetylcholine receptors free from rocuronium in the diaphragmatic neuromuscular junctions, instead of increasing the amount of acetylcholine (like neostigmine does), sugammadex will result in a better neuromuscular coupling. This may have its subsequent effects on the central control of breathing, influencing the balance between intercostal and diaphragm activity. The investigators now propose a study in rats, where the investigators will use Functional Respiratory Imaging (FRI, property of FluidDA n.v., Groeningenlei 132, B-2550 Kontich) to assess regional lung ventilation after sugammadex, neostigmine or spontaneous reversal. The images obtained through micro-CT scans allow us to accurately reconstruct airway morphology in the free-breathing rat. It will provide us with new insights into breathing physiology after reversal of neuromuscular blockade.

Detailed Description
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This study is designed to assess the effect of sugammadex, neostigmine/glycopyrrolate and spontaneous reversal of a moderate rocuronium-induced neuromuscular blockade on regional lung ventilation. This is a randomized, controlled, parallel-group double blind trial in rats. A total of 18 adult male Sprague-Dawley rats will be used, 6 in each treatment group. The animals will be randomized in one of three groups, in a 1:1:1 ratio. This randomization will be performed according to a computer-generated randomization list. The first group will receive neostigmine/glycopyrrolate. The second group will receive sugammadex. The third group will receive water for injection. Reversal agents will be administered at a train-of-four (TOF) of 0.5, as measured with AMG. The investigators will assess regional ventilation by means of micro-CT scanning during spontaneous breathing after the TOF ratio has reached ≥ 0.9. This way, the investigators can accurately reconstruct airway morphology. The different airway sections can then be linked to the corresponding lung tissue, and a full anatomical picture is thus rendered. A comparison of morphological scans at different breathing levels (e.g. end-inspiratory and end-expiratory) will allow us to model breath-by-breath regional airway and alveolar recruitment.

Official Title
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Visualization of Regional Lung Ventilation During Neostigmine or Sugammadex Enhanced Recovery From Moderate Residual Neuromuscular Blockade in the Anaesthetized Rat Using Functional Respiratory Imaging

Conditions
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Respiratory-Gated Imaging Techniques

Intervention / Treatment
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* Drug: Neostigmine
* Drug: Sugammadex
* Drug: Water for injection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: male Sprague-Dawley rats Exclusion Criteria: N/A

Ages Eligible for Study
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Minimum Age: 3 Months
Maximum Age: 6 Months

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: neostigmine<br>Neostigmine will be dosed as 60 μg/kg, and glycopyrrolate 12 μg/kg (commercially available 5:1 co-formulation), as a single iv bolus administered over 10sec, for reversal of rocuronium-induced moderate neuromuscular blockade. | Drug: Neostigmine<br>* At a train-of-four (TOF) ratio of 0.5: administration of neostigmine 0.06 mg/kg for reversal of neuromuscular blockade.<br>* Other names: Robinul-Neostigmine;|
| Experimental: Sugammadex<br>Sugammadex will be dosed 15 mg/kg, as a single iv bolus administered over 10sec, for reversal of rocuronium-induced moderate neuromuscular blockade. | Drug: Sugammadex<br>* At a train-of-four (TOF) ratio of 0.5: administration of sugammadex 15 mg/kg for reversal of neuromuscular blockade.<br>* Other names: Bridion;|
| Placebo Comparator: Water for injection<br>Water will be dosed arbitrarily as a 1 mL single iv bolus administered over 10sec. | Drug: Water for injection<br>* At a train-of-four (TOF) ratio of 0.5: administration of placebo for spontaneous recovery of neuromuscular blockade.<br>* Other names: Aqua ad iniectabilia;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Regional lung ventilation assessed by means of micro-CT scanning during spontaneous breathing after recovery from neuromuscular block. | Comparison of the effect of sugammadex, neostigmine/glycopyrrolate and spontaneous recovery on regional lung ventilation in the spontaneously breathing rat, assessed by micro-CT scanning after recovery from neuromuscular block. | CT scanning will take between 5 to 8 minutes, followed by post-processing of the images. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tidal volume (TV, mL) of breaths recorded by means of micro-CT scanning during spontaneous breathing after recovery from neuromuscular block. | Comparison of the effect of sugammadex, neostigmine/glycopyrrolate and spontaneous recovery on tidal volume of breaths in the spontaneously breathing rat, assessed by micro-CT scanning after recovery from neuromuscular block. | CT scanning will take between 5 to 8 minutes, followed by post-processing of the images. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Neostigmine, Sugammadex