Metabolic Cost of IMT

Measurement of the Metabolic Cost of Inspiratory Muscle Training and Physical Rehabilitation in Mechanically Ventilated Patients; a Feasibility Study

Mechanical ventilation is a life-saving intervention used worldwide. Despite this, critically ill patients who undergo mechanical ventilation commonly develop muscle weakness; this includes limb muscle weakness and diaphragmatic weakness.

Physiotherapy interventions on critically ill patients include; mobilisation to improve limb muscle strength and function, and inspiratory muscle training which aims to target the diaphragm and accessory inspiratory muscles with the goal of improving endurance and strength. Whilst these interventions are standard practice in intensive care, little is known about the physiological load imposed on patients.

The purpose of this study is to assess the feasibility of using indirect calorimetry (measured using the Beacon Caresystem) to measure the metabolic cost (oxygen consumption [VO2] and carbon dioxide production [VCO2]) of inspiratory muscle training and physical rehabilitation in mechanically ventilated intensive care patients.

Study Overview

• Status: Completed
• Conditions: Mechanical Ventilation Complication

Detailed Description

This is an initial cross-sectional study using a non-randomised convenience sample. Patients will be studied during either rehabilitation or Inspiratory Muscle Training.

All participants will have Maximal Inspiratory Pressure (PImax) measured every 5 days. Baseline measurements of VO2 and VCO2 at rest on their baseline ventilation will be measured using the Beacon Caresystem for 1 hour before Inspiratory Muscle Training or physical rehabilitation is initiated.

Inspiratory muscle training will will performed using a resistive device (Philips Respironics ® Threshold PEP device) which is inserted into the participants ventilator tubing 30 minutes before starting inspiratory muscle training. At this point, the device will be set to its lowest setting; the resistance will be overcome by support delivered through the ventilator meaning no additional effort for the participant.

The patient will then perform 12 breaths of inspiratory muscle training at 4cmH20, and at 30%, 50% and 80% PImax with a 30 second rest every 6 breaths and a 10-20 minute rest every 12 breaths

Inspiratory muscle training will normally occur five days per a week. The Beacon Caresystem will be connected for analysis up to 2 days per week.

Participants will receive usual physiotherapy exercise. These will be prescribed by the patient's physiotherapist and may include assisted mobilisation and / or upper and lower limb exercises to help strengthen muscles. Exercises performed will be categorised for analysis in the study according to a scale called the intensive care mobility scale.

When physical rehabilitation begins (i.e when the patient starts to move with the physiotherapist); a time stamp will be activated on the Beacon Caresystem. When physical rehabilitation has ended the time stamp will be deactivated.

Immediately after exercise the patient will be asked to rate their exertion using a simple scale designed to measure physical effort, called the BORG rating scale of perceived exertion.

Physical rehabilitation will normally occur six days per a week. The Beacon Caresystem will be connected for analysis up to 4 days per week.

• Study Type: Observational
• Enrollment (Actual): 40

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, SW6 3NP
    • The Royal Brompton and Harefield Hospitals

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Mechanically ventilated patients

Description

Inclusion Criteria:

• Patient invasively ventilated for ≥ 72 hours
• Have an endotracheal tube or tracheostomy in situ
• Respiratory rate of ≤ 35 breaths/min
• Fraction Inspired Oxygen (Fi02) ≤ 0.50
• Co-operative and able to participate in physical rehabilitation and inspiratory muscle training
• Age ≥ 18 years
• Patient consent or, in the case that the patient is unable, advice from the next of kin and acceptance of oral and written information describing the study.

Exclusion Criteria:

• Undrained pneumothorax/pneumomediastinum
• The absence of an arterial catheter for blood sampling at study start
• Unlikely to survive
• Pregnancy
• Consultant discretion that patient is not appropriate

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recruitment	The number of patients recruited to the trial compared to the number of eligible patients within the recruitment window	Through study completion, 9 months
Adherence to IMT	The adherence to the prescribed IMT protocol, including reasons for non-adherence	Throughout the trial period of each participant whilst enrolled i study
Prevalence of technical issues with relation to the Beacon Caresystem	Defined as inability to calibrate before intervention, missing data during interventions, inability to analyse data from interventions.	Through study completion, 9 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of VO2 and VCO2 in ICU patients at rest	Measured in ml/kg/min calculated as the mean VO2 and VCO2 during 60 consecutive minutes where there was a <10% variation in VO2 and VCO2 at rest	60 minutes before physical rehabilitation or inspiratory muscle training
Comparison of VO2 and VCO2 during IMT at different percentages of PImax within and between patients	Measured in ml/kg/min for the total IMT session (2 sets of 6 breaths) and 30 minutes after the intervention (analysis of recovery time to baseline)	During inspiratory muscle training and for 30 minutes after inspiratory muscle training has ceased
Prevalence of low PImax in patients receiving mechanical ventilation and PImax change during course of their admission	Measured in cmH20 at baseline and every five days	Day 0 (baseline) and every 5 days whilst the participant is enrolled in the study
Comparison of VO2 and VCO2 during physical rehabilitation in patients receiving mechanical ventilation	Measured in ml/kg/min 30 minutes before the intervention, total VO2 and VCO2 during the intervention and 30 minutes after the intervention	During physical rehabilitation and for 30 minutes after physical rehabilitation has ceased

Collaborators and Investigators

• Sponsor: Royal Brompton & Harefield NHS Foundation Trust
• Collaborators: Aalborg University
• Investigators: Principal Investigator: Micheal Polkey, PhD, Guy's and St Thomas' NHS Foundation Trust

Study record dates

Study Major Dates

• Study Start (Actual): October 18, 2021
• Primary Completion (Actual): May 16, 2022
• Study Completion (Actual): May 16, 2022

Study Registration Dates

• First Submitted: September 30, 2021
• First Submitted That Met QC Criteria: October 21, 2021
• First Posted (Actual): November 1, 2021

Study Record Updates

• Last Update Posted (Actual): May 26, 2022
• Last Update Submitted That Met QC Criteria: May 25, 2022
• Last Verified: May 1, 2022

More Information

Terms related to this study

• Other Study ID Numbers: 298839

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