An observational study in Resting Energy Expenditure and Indirect Calorimetry, sponsored by Diskapi Yildirim Beyazit Education and Research Hospital. Not yet recruiting. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-08-27.
Sponsored by Diskapi Yildirim Beyazit Education and Research Hospital · Observational
The primary objective of this prospective observational study is to compare the effects of synchronized intermittent mandatory ventilation in pressure-controlled mode (SIMV-PC) and volume-controlled mode (SIMV-VC) on resting energy expenditure (REE) measured by indirect calorimetry in adult intensive care unit (ICU) patients receiving invasive mechanical ventilation.
The primary metabolic parameters to be evaluated are oxygen consumption (VO₂), carbon dioxide production (VCO₂), resting energy expenditure (REE), and respiratory quotient (RQ). Secondary objectives include comparison of respiratory rate, tidal volume, minute ventilation,arterial blood gas parameters, mechanical power, ventilator mechanics, hemodynamic variables, sedation level, and patient-ventilator synchrony between the two ventilation modes.
The results of this study may contribute to identifying ventilation strategies associated with lower energy expenditure while maintaining adequate ventilatory support in critically ill patients and may help optimize individualized ventilator management and nutritional therapy.
Mechanical ventilation is a cornerstone of supportive therapy in critically ill patients. Although synchronized intermittent mandatory ventilation in pressure-controlled (SIMV-PC) and volume-controlled (SIMV-VC) modes are widely used in routine intensive care practice, limited data are available regarding their effects on patients' energy expenditure measured by indirect calorimetry.
Indirect calorimetry is recommended by the European Society for Clinical Nutrition and Metabolism (ESPEN) as the reference standard for determining energy expenditure in critically ill patients. Accurate estimation of energy expenditure is essential for optimizing nutritional therapy and avoiding both underfeeding and overfeeding. Overfeeding may increase carbon dioxide production, insulin requirements, respiratory workload, duration of mechanical ventilation, and intensive care unit length of stay.
This is a prospective, observational, repeated-measures study conducted in adult ICU patients receiving invasive mechanical ventilation. The study is non-interventional. Ventilation mode selection and all ventilator adjustments will be determined exclusively by the attending intensive care physician according to routine clinical practice. No study-specific ventilator changes, additional invasive procedures, or additional blood sampling will be performed.
Indirect calorimetry measurements will be performed during clinically stable periods under routine ICU monitoring. Measurements will be obtained only after at least 30 minutes of stabilization following any clinically indicated ventilation mode change. Patients receiving continuous enteral nutrition with no major changes in sedative or analgesic infusions during the preceding two hours will be eligible for metabolic measurements. Sedation level will be documented using the Richmond Agitation-Sedation Scale (RASS).
Metabolic parameters obtained by indirect calorimetry, including oxygen consumption (VO₂), carbon dioxide production (VCO₂), resting energy expenditure (REE), and respiratory quotient (RQ), will be compared between SIMV-PC and SIMV-VC ventilation modes. Ventilator parameters, respiratory mechanics, mechanical power, arterial blood gas findings, hemodynamic variables, and patient-ventilator synchrony will also be evaluated.
Because the study is observational and based entirely on routine clinical care, no additional risks beyond standard intensive care management are anticipated. If hemodynamic or respiratory instability develops during indirect calorimetry measurements, the measurement will be discontinued immediately and routine patient management will continue according to the attending physician's clinical judgment.
Diskapi Yildirim Beyazit Education and Research Hospital is the lead sponsor of 71 studies on the registry; 12 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Receiving invasive mechanical ventilation in the intensive care unit. Receiving continuous enteral nutrition during indirect calorimetry measurements.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
In intensive care patients monitored with mechanical ventilation, energy consumption will be monitored using indirect calorimetry after volume-controlled or pressure-controlled ventilation.
Other: Volume-controlled ventilation · Other: Pressure-controlled ventilation
In intensive care patients monitored with mechanical ventilation, energy consumption will be monitored using indirect calorimetry after volume-controlled ventilation.
In intensive care patients monitored with mechanical ventilation, energy consumption will be monitored using indirect calorimetry after pressure-controlled ventilation.
Resting energy expenditure (REE) measured by indirect calorimetry.
Resting energy expenditure (REE) measured by indirect calorimetry.
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Respiratory rate
Respiratory rate
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Tidal volume
Tidal volume
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Peak inspiratory pressure (Ppeak)
Peak inspiratory pressure (Ppeak)
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Positive end-expiratory pressure (PEEP)
Positive end-expiratory pressure (PEEP)
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Fraction of inspired oxygen (FiO₂)
Fraction of inspired oxygen (FiO₂)
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Arterial blood gas parameters (pH)
Arterial blood gas parameters (pH)
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Arterial blood gas parameters (PaCO₂)
Arterial blood gas parameters (PaCO₂)
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Arterial blood gas parameters (PaO₂)
Arterial blood gas parameters (PaO₂)
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
Arterial blood gas parameters (Lactate)
Arterial blood gas parameters (Lactate)
Time frame: After being monitored in mechanical ventilation mode (volume or pressure controlled) for 2 hours
No study locations are listed for this record.
Plan to share: No
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Diskapi Yildirim Beyazit Education and Research Hospital