Respiratory Muscle Training in the ICU: IMT vs Diaphragmatic NMES

May 2, 2026 updated by: Ali Yalman

Comparing the Effects of Inspiratory Muscle Training and Diaphragmatic Neuromuscular Electrical Stimulation in Mechanically Ventilated Patients: A Randomized Controlled Trial

This study aimed to compare the effects of Inspiratory Muscle Training (IMT) and Diaphragmatic Neuromuscular Electrical Stimulation (NMES) on inspiratory muscle strength, mechanical ventilator parameters, and functional levels in intubated intensive care unit (ICU) patients. Thirty-two intubated patients were divided into two groups: the IMT group and the NMES group. In the IMT group, IMT was administered twice a day in addition to routine physiotherapy. In the NMES group, electrical stimulation was applied to the diaphragm muscle for 40 minutes in addition to routine physiotherapy. The primary outcomes of the study are inspiratory muscle strength and physical function level. The secondary outcomes are mechanical ventilator parameters, extubation time, and length of hospital stay.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This randomized study aimed to compare the effects of Inspiratory Muscle Training (IMT) and Neuromuscular Electrical Stimulation (NMES) on inspiratory muscle strength, mechanical ventilator parameters, and functional levels in intensive care unit (ICU) patients.

A total of 32 mechanically ventilated patients were randomly assigned to either an IMT group (n=16) or an NMES group (n=16). In addition to routine ICU physiotherapy, the IMT group received inspiratory muscle training using Philips Respironics Threshold IMT devices, while the NMES group received stimulation on the diaphragm with Aussie current using surface electrodes.

Study Type

Interventional

Enrollment (Actual)

32

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

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria

  • Being intubated
  • Conscious state
  • Ability to trigger mechanical ventilation
  • Capability to execute at least one motor command

Exclusion Criteria

  • Any neurological or orthopedic diagnosis or deficits
  • Inability to cooperate with the physiotherapist
  • Hemodynamic instability despite medical treatment
  • Excessive secretions requiring aspiration more than once per hour.

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Inspiratory Muscle Training (IMT)
As a result of randomization, the IMT group consisted of 16 participants with a mean age of 70 ± 9.57 years. IMT was administered to the participants twice a day following routine physiotherapy, which included breathing exercises and mobilization.
Procedure: Inspiratory muscle training (IMT)
Routine ICU physiotherapy includes: conventional chest physiotherapy, consisting of diaphragmatic breathing, thoracic expansion exercises, postural drainage, cough training, and in-bed ROM exercises and mobilization. In addition to routine ICU physiotherapy, patients received IMT twice daily with Threshold IMT devices (Respironics, New Jersey, Inc., NJ, USA). The IMT program started at 30% of pretreatment Pimax and was increased by 2H2O daily according to patients' tolerance. A total of 3 sets of 8 repetitions were applied.
Experimental: Neuromuscular electric stimulation (NMES)
As a result of randomization, the NMES group consisted of 16 participants with a mean age of 65.31 ± 8.38 years. Following routine intensive care physiotherapy, which included breathing exercises and mobilization, NMES was applied to the diaphragm muscle for 40 minutes.
Procedure: Diaphragmatic Neuromuscular Electric Stimulation (NMES)
Routine ICU physiotherapy includes: conventional chest physiotherapy, consisting of diaphragmatic breathing, thoracic expansion exercises, postural drainage, cough training, and in-bed ROM exercises and mobilization. In addition to routine ICU physiotherapy, patients received NMES on the diaphragm with surface electrodes. Electrodes were placed at four channels with two electrodes on both sides of the xiphoid at the level of the intercostal space of the 7th and 8th ribs, superiorly and inferiorly. In addition, two electrodes with two channels were placed superiorly and inferiorly at the midaxillary level of the intercostal space of the 7th and 8th ribs. A total of 4 channels and 8 electrodes were used with modified burst series biphasic current 30 Hz (Aussie current).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Inspiratory muscle strength
Time Frame: Baseline, 1 hour before extubation, 1 hour before discharge
Inspiratory muscle strength (Pimax) was assessed by a desktop spirometer with Pimax module (Pony Fx, COSMED, Rome, Italy). A catheter mount piece was placed in front of the pressure measurement part of spirometer to perform the measurement in intubated participants. Participants were encouraged throughout the measurements to achieve maximum strength and coordination. The measurements were repeated three times, and the average of these values was recorded. To prevent respiratory muscle fatigue, at least a one-minute break was provided between trials. Results were reported in cmH2O units.
Baseline, 1 hour before extubation, 1 hour before discharge
Physical Functions
Time Frame: Baseline, 1 hour before discharge
Physical function levels of patients were evaluated by Physical Function Intensive Care Unit Test-scored (PFIT-s). Physical Function Intensive Care Unit Test-scored has 4 test components; shoulder flexion strength, knee extension strength, sit to stand assistance, step cadence. Before the test, the participant was expected to correctly answer 2 of 5 questions to assessing the cooperation. Participants' vital signs were noted before and after the test. Participants are scored on a total scale ranging from 0 to 10. A score of 0 signifies total dependence and poor muscle strength, whereas a score of 10 represents functional independence and optimal muscle strength.
Baseline, 1 hour before discharge

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mechanical Ventilatory Parameters - Tidal Volumes
Time Frame: Baseline, 1 hour before extubation
Respitatory parameters were assessed by mechanic ventilator (The Engstrom Carestation, GE Health Care 2016). The test procedure; device was switched to CPAP mode, Psupport was set to 10 cmH2O and PEEP was set to 5 cmH2O to overcome the physiological resistance of the ventilator circuit. The patient was instructed to take deep breaths for one minute. As the measurements required patient motivation and coordination, the tests were conducted by providing appropriate verbal commands. Inspiratory tidal volume (TVi) and expiratory tidal volume (TVe) were recorded in milliliters (ml).
Baseline, 1 hour before extubation
Mechanical Ventilatory Parameter - Minute Ventilation
Time Frame: Baseline, 1 hour before extubation
Respitatory parameters were assessed by mechanic ventilator (The Engstrom Carestation, GE Health Care 2016). The test procedure; device was switched to CPAP mode, Psupport was set to 10 cmH2O and PEEP was set to 5 cmH2O to overcome the physiological resistance of the ventilator circuit.The patient was instructed to perform deep breathing for a period of one minute. Since the measurement required patient motivation and coordination, the tests were conducted by providing appropriate verbal commands. Minute ventilation was recorded in liters per minute (L/min)
Baseline, 1 hour before extubation
Length of time intubated
Time Frame: 12 hours after extubation
The duration of intubation for the participants was reported in days.
12 hours after extubation
Hospital stay length
Time Frame: 2 hours after discharge
The duration of hospital stay was reported in days
2 hours after discharge

Collaborators and Investigators

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

Sponsor

Ali Yalman

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

March 5, 2020

Primary Completion (Actual)

October 20, 2021

Study Completion (Actual)

November 23, 2021

Study Registration Dates

First Submitted

April 11, 2026

First Submitted That Met QC Criteria

May 2, 2026

First Posted (Actual)

May 6, 2026

Study Record Updates

Last Update Posted (Actual)

May 6, 2026

Last Update Submitted That Met QC Criteria

May 2, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 60116787-020/46004

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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