Using sEMG of the Diaphragm to Assess Readiness for Extubation

Using sEMG of the Diaphragm to Assess Readiness for Extubation - Feasibility Study to Design a Pragmatic Multi-site Trial Protocol

As part of an admission to an Intensive Care Unit (ICU) many patients have breathing tube inserted into their windpipe, also referred to as intubation . This is done for a variety of reasons which can include the need for invasive breathing support and to place the patient into a medically induced coma to allow their body to rest and be treated for the underlying cause of their deterioration.

One the patient has started to recover from their illness, the process of removing the breathing tube (extubation) and stopping the breathing machine begins. Optimising this process and ensuring successful removal of the breathing tube is extremely important to optimise outcomes. Therefore, identifying new methods to determine the likelihood for successful extubation is of clinical significance.

There are several markers of extubation readiness that clinicians can use to support their decision making discussed in the literature. A novel method is the use of respiratory muscle activity monitoring via sensory electromyogram (sEMG). sEMG has previously been shown to be useful to measure the strength and activity of muscles. However, until recently measuring diaphragm activity has been a challenge due to noise from the chest movements, cardiac artefacts. Recent advancements in signal processing and growing interest in better diagnostic methods has led to an improvement in metrics. Using wavelet transforms and machine learning, new techniques have been developed to measure diaphragm muscle activity using sEMG. sEMG has been shown to be effective in detecting patient-ventilator asynchrony as well as respiratory strength in those not requiring mechanical ventilation. However, its use in assessing patients nearing readiness for extubation has not been explored.

Therefore, the purpose of this feasibility trial is to explore the use of sEMG in patients undergoing trials of extubation. The results of this study will be used to design a multi-site trial.

Study Overview

• Status: Recruiting
• Conditions: Critical Illness

Detailed Description

150,000 patients a year in the UK need to be admitted to a critical care unit. Those admitted are usually either critically unwell or are in the recovery phase of a critical illness (1). Often patients will require support for one or more of their vital organs such as their lungs, heart or kidneys. Approximately 60% of patients admitted will require support from mechanical ventilation (breathing machine) (2).

Mechanical ventilation is lifesaving when indicated but is beset by potential complications as the duration increases (3). Early identification of patients who are ready to be liberated from ventilatory support is therefore key. However, clinician judgement lacks both sensitivity and specificity for identifying such patients.

A Cochrane review in 2010 (4) demonstrated protocolised and standardised weaning method reduced the duration of total mechanical ventilation by 25%, weaning duration time by 78% and Intensive Care Unit (ICU) length of stay by 10%. Conversely, prolonged weaning process worsens patient outcomes, increases the risk of dying, and increases length of ICU and hospital stay, affects finite critical care resource and a direct impact on financial cost and environment sustainability (5).

Predicting readiness for extubation is challenging. This task is best accomplished by means of a protocolised process including a spontaneous awakening trial (SAT) where sedation is lowered to a safe RASS target and a spontaneous-breathing trials (SBT), in which patients who meet a defined set of criteria undergo a test period of minimal (Pressure support ventilation) or no ventilator (T-piece) support (6). This is then frequently combined with objective markers or 'extubation indices'. These indices include assessments of breathing strength and endurance, cough strength and respiratory distress e.g., P0.1, MIP, Peak cough flow and RSBI. However, these indices have been shown to lack sensitivity and specificity, with none of them able to accurately predict readiness for extubation or likely success (7).

The incidence of extubation failure reported in literature is quite variable with ~5% in post-operative surgical units to 10% in medical ICUs. With each additional day without a weaning success after the first attempt, there is an associated increase in crude mortality. Crude mortality increased from 19.0% in patients not weaned one day after the first attempt to 36.8% in patients still present in the ICU and not successfully weaned 10 days after the first attempt (8). Studies have also demonstrated that patients requiring reintubation are at increased risk of death with mortality rates ranging as high as 43% compared with less than 12% in patients successfully extubated (9). Reintubation is associated with a 4.5 times increased risk of nosocomial pneumonia (10).

Therefore, identifying new methods for determine likelihood for successful extubation is of clinical importance. Once such novel method is the use of respiratory muscle activity monitoring via sensory electromyogram (sEMG). sEMG has previously been shown to be useful to measure the strength and activity of muscles (11). However, until recently measuring diaphragm activity has been a challenge due to noise from the chest movements, cardiac artifacts. Recent advancements in signal processing and growing interest in better diagnostic methods has led to an improvement in metrics (12). Using wavelet transforms and machine learning, new techniques have been developed to measure diaphragm muscle activity using surface EMG electrodes placed at the 6-8th intercostal space along the mid-axillary or mid-clavicular line (13). Indeed, a pilot study looking at the sEMG of the diaphragm in healthy humans has shown that we are able to predict the inspiratory load of 6 participants with over 70% accuracy. sEMG has also been shown to be effective in detecting patient-ventilator asynchrony as well as respiratory strength in those not requiring mechanical ventilation (14). However, its use in assessing patients nearing readiness for extubation has not been explored.

Therefore, the purpose of this feasibility trial is to explore the use of sEMG in patients undergoing trials of extubation. The results of this study will be used to design a multi-site trial.

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

• Study Contact: Name: Paul Twose, PhD; Phone Number: +447739315830; Email: paul.twose@wales.nhs.uk

Study Locations

• United Kingdom
  • Cardiff, United Kingdom, CF144XW
    • Recruiting
    • Cardiff and Vale University Health Board
    • Contact: Paul Twose; Phone Number: 00447739315830; Email: paul.twose@wales.nhs.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients admitted to critical care for level 3 support

Description

Inclusion Criteria:

• Patients requiring mechanical ventilation for >72 hours
• Patients who an attempt at extubation is planned
• Patients who are willing or able to give informed consent (Where consultee advice is sought, informed consent from the participant will be completed as soon as possible).

Exclusion Criteria:

• Aged under 18 years
• Patients admitted with traumatic or spontaneous brain injury
• Patients for who extubation is planned as a palliative process
• Contra-indication to using sEMG e.g., permanent or temporary pacemaker, internal or external cardiac defibrillator, skin lesions around site of electrode placement

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Critical care cohort; Critical care cohort - all to have EMG completed. No other intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Feasibility of recruitment and retention of participants	To determine study feasibility by recruitment and retention rates from study participants across a single site	1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Appropriateness of use of EMG for diaphragm strength	To determine the appropriateness of sEMG in assessing diaphragm strength in relation to extubation	1 year

Collaborators and Investigators

• Sponsor: Cardiff and Vale University Health Board

Study record dates

Study Major Dates

• Study Start (Estimated): August 31, 2025
• Primary Completion (Estimated): January 31, 2026
• Study Completion (Estimated): July 31, 2026

Study Registration Dates

• First Submitted: July 31, 2025
• First Submitted That Met QC Criteria: July 31, 2025
• First Posted (Actual): August 7, 2025

Study Record Updates

• Last Update Posted (Actual): August 21, 2025
• Last Update Submitted That Met QC Criteria: August 20, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Critical Illness
• Other Study ID Numbers: 8999; IRAS 353832 (Other Identifier: IRAS)

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