Phrenic Nerve Block to Mitigate Self-inflicted Lung Injury

September 28, 2020 updated by: University of Sao Paulo General Hospital

Feasibility of Phrenic Nerve Block to Mitigate Self-inflicted Lung Injury in ARF Patients Under Mechanical Ventilation on Spontaneous Breathing

The purpose of this single-centered, proof of concept study is to determine whether it is feasible to perform a phrenic nerve block to reduce diaphragm electrical activity and, therefore, inspiratory effort and if such block reduces self-inflicted lung injury on patients under mechanical ventilation on spontaneous breathing. Ten patients will be monitored with electrical impedance tomography, NAVA catheter, and esophageal balloon. Using a nerve stimulator and an ultrasound, we will identify the phrenic nerve on its cervical portion bilaterally and administer perineural low-dose lidocaine. Diaphragm electrical activity, transpulmonary pressure and data on ventilation distribution will be continuously collected. The study will be over once the patient presents the same diaphragm electrical activity and transpulmonary pressure as before the phrenic nerve block.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The use of protective mechanical ventilation has improved prognosis on patients with Acute Respiratory Failure. The association of neuromuscular blockade in the first 48-72h has additionally contributed to a higher survival rate. Such improvement may be due to the reduction of transpulmonary pressures caused by the patient's inspiratory effort. To achieve appropriate neuromuscular blockade, highes doses of both neuromuscular blocking agents and sedatives are required. Therefore, such a strategy usually causes muscular atrophy, including the diaphragm.

Because of the augmented neural drive of such patients, exacerbated by inflammation and pulmonary edema, the consequent high tidal volume and transpulmonary pressure cannot be reduced by the newest sedatives. In fact, some of these sedatives may even deteriorate ventilatory dyssynchrony. Our intention is to verify a novel approach: whether is possible to reduce the inspiratory effort of patients without the use of systemic neuromuscular blocking agents.

Our objective in this proof of concept study is to determine the feasibility the use of phrenic nerve blockade to decrease transpulmonary pressure and tidal volume, as well as quantify its effects on esophageal pressure, diaphragmatic electrical activity, transpulmonary pressure and ventilation distribution in patients on spontaneous breathing. It is expected that such intervention will reduce diaphragm electrical activity, leading to lower transpulmonary pressure, tidal volume and driving pressures.

All patients will be submitted to the same intervention. Respiratory mechanics, ventilation distribution, diaphragm electrical activity, heart rate, mean arterial pressure and peripheral saturation will be collected throughout the study. Once the patient presents the same diaphragmatic electrical activity and transpulmonary pressure as before the phrenic nerve block, the study will be over.

Study Type

Interventional

Enrollment (Actual)

10

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Brazil
      • São Paulo, Brazil, 01246-903
        • Hospital das Clínicas - Faculdade de Medicina da Universidade de Sao Paulo

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age > 17 years-old;
  • Under mechanical ventilation on spontaneous breathing, capable of triggering the ventilator with P/F < 300;
  • Tidal volume > 10ml/kg with inspiratory pressure of 12 cmH2O OR driving pressure > 15 cm H2O with inspiratory pressure of 12 cmH2O

Exclusion Criteria:

  • Use of neuromuscular blocking agents less than 3h;
  • Richmond Agitation-Sedation Scale (RASS) > 0;
  • Arterial pH < 7.25;
  • Hemodynamically unstable or with increasing doses of vasopressors in the last 2h;
  • Intracranial hypertension;
  • Thoracic or abdominal tubes;
  • Any neuromuscular disease;
  • Spinal injury;
  • Ascitis;
  • Thoracic burn injury;
  • Tetanus;
  • Pregnancy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Supportive Care
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Phrenic Nerve Blockade
All patients will be submitted to bilateral phrenic nerve block on its cervical portion.
Drug: Lidocaine
Using an ultrasound and a nerve stimulator, the phrenic nerve will be identified and low-dose lidocaine will be administered perineurally.
Other Names:
  • Local anesthetic

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Reduction of tidal volume or transpulmonary pressure
Time Frame: 20 minutes
Tidal volume or transpulmonary pressure measured using EIT, Servo-I and an esophageal balloon
20 minutes

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Reduction of the inspiratory effort
Time Frame: 20 minutes - 3 hours
Diaphragm electrical activity using NAVA
20 minutes - 3 hours
Consequences on mechanical ventilation
Time Frame: 20 minutes - 3 hours
Tidal volume, pendellfut and asynchronies measured by EIT
20 minutes - 3 hours
Time to complete weaning of the blockade
Time Frame: 30 minutes - 3 hours
Patients will be monitored until full recover of inspiratory effort or diaphragm electrical activity
30 minutes - 3 hours
Reduction of the inspiratory effort
Time Frame: 20 minutes - 3 hours
Esophageal pressure using an esophageal catheter
20 minutes - 3 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Sao Paulo General Hospital

Investigators

  • Principal Investigator: Marcelo BP Amato, MD, PhD, University of Sao Paulo School of Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 15, 2019

Primary Completion (Actual)

December 31, 2019

Study Completion (Actual)

September 9, 2020

Study Registration Dates

First Submitted

May 10, 2019

First Submitted That Met QC Criteria

June 5, 2019

First Posted (Actual)

June 7, 2019

Study Record Updates

Last Update Posted (Actual)

September 30, 2020

Last Update Submitted That Met QC Criteria

September 28, 2020

Last Verified

May 1, 2019

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CAAE 02029118.2.0000.00.68

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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