Effect of Diaphragm Stimulation During Surgery

NCT03303040 | Completed Results DMC

• 2 other identifiers: IRB201602186-NR01AR072328
• Study Type: interventional
• Target: 25
• Locations: 1 country
• Sites: 1

Brief Summary

During major surgical procedures general anesthesia is used to make the patient unconscious. General anesthesia insures that the patient is unaware of any pain caused by surgery. General anesthesia also prevents the patient from moving to prevent any potential surgical error. At the same time general anesthesia makes it impossible for the patient to breathe. To help the patient breathe a breathing tube is placed into the patient's airway and connected to the mechanical ventilator. A mechanical ventilator is an artificial breathing pump, which delivers gas into a patient's airways. The purpose of this research study is to determine if brief periods of diaphragm stimulation can prevent diaphragm problems caused by the use of mechanical ventilators and surgery. To answer this question the changes in the genes responsible for maintaining diaphragm function will be studied. A gene is the code present in each cell in your body and controls the behavior of that cell. In addition, the changes in the contractile properties of muscle fibers will be studied. The results from this study may help develop new treatments to prevent diaphragm weakness resulting from mechanical ventilation use.

Conditions

Mechanical Ventilation Complication; Diaphragm Injury

Keywords

Mechanical ventilation; Diaphragm weakness; Difficulty weaning from mechanical ventilation; Diaphragm stimulation

Outcome Measures

Primary Outcomes (15)

• Mitochondrial Respiration

  High-resolution respirometry will be used to assess mitochondrial respiration of permeablilized diaphragm bundles. Addition of substrate medium to the Oroboros O2K respirometry instrument enables quantification of leak respiration and peak uncoupled respiration, expressed as pmol oxygen/sec/mg wet weight.

  Up to eight hours

• Aconitase Activity

  In order to evaluate mitochondrial damage, actonitase activity will be measured spectrophotometrically. It will be quantified as units/mg protein.

  Up to eight hours

• Lipid Peroxidation

  Lipid peroxidation will be assessed by measuring 4-hydroxy-2-nonenal-modified proteins. It will be quantified as arbitrary optical density units.

  Up to eight hours

• Citrate Cynthase Activity

  Changes in electron transport chain will be assessed by measuring citrate cynthase activity. It will be quantified as nmol/mg protein/min.

  Up to eight hours

• Single Diaphragm Fiber, Specific Force

  Specific force of single diaphragm fibers represents the force generated per unit area.

  Up to eight hours

• Single Diaphragm Fiber, Rate of Tension Redevelopment

  Single diaphragm fiber mechanical force properties will be measured. The rate of tension redevelopment is quantified as s\^(-1).

  Up to eight hours

• Calcium Sensitivity (pCa50)

  The pCa50 value is the logarithmic scale of pCa (sensitivity of Ca+2) at which half-maximal force generation was obtained. The pCa value is calculated as the -log10\[Ca (nm)\]; the pCa50 is the -log10\[Ca (nm)\] at which half-maximal force is generated.

  Up to eight hours

• Difference in Total Titin to Myosin Heavy Chain Ratio

  The quantities of total titin protein and myosin heavy chain protein content in homogenized diaphragm fiber specimens were measured and then calculated as a ratio of total titin to myosin heavy chain content (unitless value). The statistical approach was selected apriori as the difference of the ratio between the stimulated and unstimulated sides.

  Up to eight hours

• Difference in Titin Exon Composition

  The composition of titin exons will be assessed and quantified via real-time polymerase chain reaction (qPCR). The N2A and tT2 will be calculated as a percentage of total titin.

  Up to eight hours

• Difference in Titin Binding Protein Content

  The content of titin binding proteins will be quantified via Western blot. It will be normalized to a reference protein (GAPDH) and presented as optical intensity (AU).

  Up to eight hours

• Difference in Calpain 1 Protein Content

  Calpain 1 (mu-calpain) will be measured with Western Blot analysis and will be presented as percent of total intensity in stimulated and unstimulated hemidiaphragms

  Up to eight hours

• Difference in Calpain 2 Protein Content

  Calpain 2 will be measured with automated, capillary-based immunoassay using a Jess System, normalized to total protein, and will be presented as an area of corrected peak (AU) in stimulated and unstimulated hemidiaphragms.

  Up to eight hours

• Difference in Calpain 3 Protein Content

  Calpain 3 will be measured with Western Blot analysis and will be presented as a ratio of cleaved to total calpain 3 (unitless value) in stimulated and unstimulated hemidiaphragms.

  Up to eight hours

• Difference in Caspase-3 Protein Content

  Caspase-3 will be measured with Western Blot analysis, normalized to total protein loaded in each lane, and will be presented as an area of corrected peak (AU) in stimulated and unstimulated hemidiaphragm muscle fibers.

  Up to eight hours

• Atrogin 1

  Atrogin 1 will be measured with Jess protein immunoassay analysis, normalized to total protein, and will be presented as the corrected peak area (AU) in stimulated and unstimulated hemidiaphragm muscle fibers.

  Up to eight hours

Other Outcomes (13)

• Mitochondrial Reactive Oxygen Species Production

  Up to eight hours

• Cytochrome c Oxidase (COX) Activity

  Up to eight hours

• Nuclear DNA Mutation Frequency

  Up to eight hours

Study Arms (2)

Stimulation

EXPERIMENTAL

Electrical stimulation of hemidiaphragm

Other: Electrical stimulation of hemidiaphragm

Control

NO INTERVENTION

No stimulation of hemidiaphragm

Interventions

Electrical stimulation of hemidiaphragm OTHER

Electrical impulses

Stimulation

Eligibility Criteria

• Age: 18 Years - 85 Years
• Gender Eligibility Details: 12 females and 12 males (based on gender identity) will be recruited for the study
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients undergoing complex, elective prolonged surgeries, usually lasting 5-8 hours or longer, including lung transplants (e.g. valveoplasty, coronary artery bypass and/or aortic repairs)

You may not qualify if:

• history of prior surgery to the diaphragm or pleura;
• a diagnosis of COPD will be determined from a clinical history consistent with chronic bronchitis and/or emphysema, a long history of cigarette smoking, and pulmonary function tests consistent with irreversible airflow obstruction (FEV1 \< 40% predicted, according to European Respiratory Society criteria \[will not apply to transplant patients\]
• a diagnosis of chronic heart failure (NYHA class IV)
• clinical diagnosis of other lung disease (cystic fibrosis, bronchiectasis, lung cancer; etc.) \[will not apply to transplant patients\]
• renal insufficiency (serum creatinine \> 1.6 mg/dl);
• severe hepatic disease (any liver function tests \> 1.5 times the upper limit of normal);
• undernourishment (body mass index \< 20 kg/m2),
• chronic uncontrolled or poorly controlled metabolic diseases (e.g., diabetes, hypo- or hyperthyroidism)
• orthopedic diseases, suspected paraneoplastic or myopathic syndromes,
• if in the surgeons' judgment the patients' clinical status warrants, diaphragm stimulation will be stopped and biopsies will not be obtained,

Sponsors & Collaborators

• National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS): collaborator
• University of Florida: lead
• National Institutes of Health (NIH): collaborator
• University of Arizona: collaborator

Study Sites (1)

University of Florida

Gainesville, Florida, 32610, United States

Location

Results Point of Contact

• Title: Dr. Barbara K. Smith
• Organization: University of Florida

bksmith@ufl.edu

352-294-5315

Study Officials

• Anatole D Martin, PhD

  University of Florida

  PRINCIPAL INVESTIGATOR

• Thomas M Beaver, MD

  University of Florida

  PRINCIPAL INVESTIGATOR

• Barbara Smith, PhD, PT

  University of Florida

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This is a within subjects design. One side of each subject's diaphragm will be stimulated. The other side of the subject's diaphragm will not be stimulated and will therefore serve as the control. Biopsies will be taken from both sides and compared.

Study Record Dates

• First Submitted: September 26, 2017
• First Posted: October 5, 2017
• Study Start: February 14, 2018
• Primary Completion: May 31, 2022
• Study Completion: December 31, 2023
• Last Updated: June 26, 2024
• Results First Posted: May 30, 2024

Record last verified: 2024-06

Locations

US (1)