Phrenic Nerve Block to Mitigate Self-inflicted Lung Injury

NCT ID: NCT03978845

Last Updated: 2020-09-30

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 10 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-05-15
• Study Completion Date: 2020-09-09

Brief Summary

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.

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.

Conditions

Respiratory Failure; Mechanical Ventilation

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: SUPPORTIVE_CARE
• Blinding Strategy: NONE

Study Groups

Phrenic Nerve Blockade

All patients will be submitted to bilateral phrenic nerve block on its cervical portion.

Group Type: EXPERIMENTAL

Lidocaine

Intervention Type: DRUG

Using an ultrasound and a nerve stimulator, the phrenic nerve will be identified and low-dose lidocaine will be administered perineurally.

Interventions

Lidocaine

Using an ultrasound and a nerve stimulator, the phrenic nerve will be identified and low-dose lidocaine will be administered perineurally.

Intervention Type: DRUG

Other Intervention Names

Local anesthetic

Eligibility Criteria

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.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Sao Paulo General Hospital

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Joaquim E Vieira, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Sao Paulo School of Medicine

Marcelo BP Amato, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Sao Paulo School of Medicine

Locations

Hospital das Clínicas - Faculdade de Medicina da Universidade de Sao Paulo

São Paulo, , Brazil

Countries

Brazil

Other Identifiers

CAAE 02029118.2.0000.00.68

Identifier Type: -

Identifier Source: org_study_id