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Completed

NCT Number: NCT07063303

Circadian Rhythm in Critical Illness

The goal of this clinical trial is to determine whether intermittent enteral feeding positively influences circadian rhythms in critically ill patients in intensive care units (ICUs). The main research questions are:

1. Does intermittent feeding improve circadian rhythms in ICU patients? 2. How does intermittent feeding affect metabolic markers and recovery outcomes? Researchers will compare intermittent feeding to continuous feeding, the current standard method, to assess its impact on circadian stability and patient health.

Participants will:

1. Receive intermittent enteral feeding or continuous enteral feeding for at least 10 days 2. Undergo blood sample collection at three time points daily (morning, afternoon, midnight) to analyze circadian gene expression and metabolic markers 3. Have their clinical condition, nutrition status, and recovery progress monitored throughout the study

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Key information

Conditions

Critical Illness Disease Attributes Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Ankara Training and Research Hospital

Ankara, Turkey (Türkiye)

About this study

Circadian rhythms regulate various physiological processes over a 24-hour cycle, including sleep-wake patterns, digestion, blood pressure, and hormone secretion. These rhythms are primarily controlled by the suprachiasmatic nucleus in the hypothalamus and influenced by environmental cues (zeitgebers), such as light exposure and meal timing. Critically ill patients often experience circadian rhythm disruptions due to prolonged artificial lighting, sleep disturbances, and continuous feeding, which may negatively impact metabolic health, immune function, and recovery. Given the significance of meal timing in circadian regulation, intermittent feeding might serve as a therapeutic strategy to restore circadian balance in ICU patients.

This study is a prospective, randomized controlled trial and will be conducted at Ankara Training and Research Hospital's Anesthesia Intensive Care Unit. Ethical approval for the study has been obtained from Ankara Training and Research Hospital with decision number E-93471371-514.99-226714167.

Patients will be randomly assigned to one of two groups:

  • Intermittent Feeding Group - enteral nutrition will be provided at scheduled intervals (4-6 times daily) for 20-60 minutes per session, aligning with circadian cycles. Light exposure will also be adjusted, ensuring darkness during night hours.
  • Continuous Feeding Group - patients will receive standard continuous enteral nutrition, without specific adjustments for circadian rhythms.

Blood samples will be collected on Day 1 and Day 7 at 08:00, 16:00, and 00:00 to analyze Brain and muscle aryl hydrocarbon receptor nuclear antigen-1 (BMAL1), Cyrptochrome 1 (CRY1), and Period 2 (PER2) gene expression and biochemical markers. No invasive procedures will be performed beyond routine ICU care. Patients' medical history, nutritional status, and clinical parameters will be recorded by using Acute Physiology and Chronic Health Evaluation II (APACHE II) Score, Sequential Organ Failure Assessment (SOFA) Score, Nutrition Risk in Critically ill (NUTRIC) Score and Global Leadership Initiative on Malnutrition (GLIM) Criteria.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • ICU admission for enteral feeding via a gastric tube
  • Expected ≥10 days of enteral nutrition
  • Age ≥18 years

Exclusion criteria

  • Age <18 years
  • Pregnancy
  • Gastrointestinal surgery or diseases
  • Tolerance issues with enteral feeding
  • Parenteral feeding requirement

Treatment and study plan

Intermittent feeding

Other

Feeding Frequency: Enteral nutrition will be provided every 4 to 6 hours via nasogastric tube.

Feeding Volume: Each session will deliver 240 to 720 mL of enteral formula. Feeding Duration: Each feeding session will last approximately 20 to 60 minutes.

Continuous feeding

Other

Feeding Frequency: Enteral nutrition will be administered continuously for 20 hours per day via nasogastric tube.

Feeding Volume: The total daily volume will be divided evenly over the 20-hour infusion period, based on individual nutritional requirements.

Feeding Duration: Each 24-hour cycle includes 20 hours of continuous feeding followed by a 4-hour rest period.

Primary outcomes

  1. BMAL1 mRNA Expression Level

    Time frame: From randomization to the end of intervention (7 days)

    To evaluate the circadian rhythm in critically ill patients, BMAL1 gene expression will be measured using blood samples collected at 08:00, 16:00, and 00:00 on Day 1 and Day 7

  2. CRY1 mRNA Expression Level

    Time frame: From randomization to the end of intervention (7 days)

    To evaluate the circadian rhythm in critically ill patients, CRY1 gene expression will be measured using blood samples collected at 08:00, 16:00, and 00:00 on Day 1 and Day 7

  3. PER2 mRNA Expression Level

    Time frame: From randomization to the end of intervention (7 days)

    To evaluate the circadian rhythm in critically ill patients, PER2 gene expression will be measured using blood samples collected at 08:00, 16:00, and 00:00 on Day 1 and Day 7

Secondary outcomes

  1. Fasting Glucose Level

    Time frame: From randomization to Day 7

    This parameter will be analyzed from blood samples collected on the first and seventh days after randomization. Unit of Measure: mg/dL

  2. C-reactive protein (CRP)

    Time frame: From randomization to Day 7

    This parameter will be analyzed from blood samples collected on the first and seventh days after randomization. Unit of Measure: mg/L

  3. Lactate Level

    Time frame: From randomization to Day 7

    This parameter will be analyzed from blood samples collected on the first and seventh days after randomization. Unit of Measure: mmol/L

  4. Creatinine Level

    Time frame: From randomization to Day 7

    This parameter will be analyzed from blood samples collected on the first and seventh days after randomization. Unit of Measure: mg/dL

  5. Bicarbonate Level

    Time frame: From randomization to Day 7

    This parameter will be analyzed from blood samples collected on the first and seventh days after randomization. Unit of Measure: mmol/L

  6. White Blood Cell (WBC) Count

    Time frame: From randomization to Day 7

    WBC count (x10³/μL) will be analyzed from blood samples collected on the first and seventh days after randomization.

  7. Lymphocyte Count

    Time frame: From randomization to Day 7

    Lymphocyte Count (x10³/μL) will be analyzed from blood samples collected on the first and seventh days after randomization.

  8. Neutrophil Count

    Time frame: From randomization to Day 7

    Neutrophil Count (x10³/μL) will be analyzed from blood samples collected on the first and seventh days after randomization.

  9. Hemoglobin Level

    Time frame: From randomization to Day 7

    Hemoglobin Level will be analyzed from blood samples collected on the first and seventh days after randomization. Unit of measure: g/dL

  10. Platelet Count

    Time frame: From randomization to Day 7

    Platelet Count (x10³/μL) will be analyzed from blood samples collected on the first and seventh days after randomization.

  11. Aspartate aminotransferase (AST) Levels

    Time frame: From randomization to Day 7

    Aspartate aminotransferase (AST) (U/L) levels will be analyzed from blood samples collected on the first and seventh days after randomization.

  12. Alanine aminotransferase (ALT) Levels

    Time frame: From randomization to Day 7

    Alanine aminotransferase (ALT) (U/L) levels will be analyzed from blood samples collected on the first and seventh days after randomization.

  13. Gamma glutamyl transferase (GGT) Levels

    Time frame: From randomization to Day 7

    Gamma glutamyl transferase (GGT) (U/L) levels will be analyzed from blood samples collected on the first and seventh days after randomization.

  14. Blood Urea Nitrogen (BUN) Levels

    Time frame: From randomization to Day 7

    Blood Urea Nitrogen (BUN) (mg/dL) levels will be analyzed from blood samples collected on the first and seventh days after randomization.

  15. Sodium Levels

    Time frame: From randomization to Day 7

    Sodium (mmol/L) levels will be analyzed from blood samples collected on the first and seventh days after randomization.

  16. Potassium Levels

    Time frame: From randomization to Day 7

    Potassium (mmol/L) levels will be analyzed from blood samples collected on the first and seventh days after randomization.

  17. Acute Physiology and Chronic Health Evaluation II (APACHE-II) Score

    Time frame: First day of admission to the ICU

    The APACHE II score is a clinical tool used in intensive care units to assess the severity of a patient's illness and estimate the risk of hospital mortality. It is calculated based on physiological measurements, age, and chronic health conditions. Higher scores indicate more severe illness and a greater risk of death.

    Unit of Measure: Score (0-71 scale) Interpretation: Higher scores correspond to increased severity and mortality risk.

  18. Sequential Organ Failure Assessment (SOFA) Score

    Time frame: First day of admission to the ICU

    The SOFA score evaluates the function of six organ systems-respiratory, cardiovascular, hepatic, coagulation, renal, and neurological-in critically ill patients. It is used to monitor the extent of organ dysfunction and predict clinical outcomes in the intensive care unit (ICU).

    Unit of Measure: Score (0-24 scale) Interpretation: Higher scores indicate greater organ dysfunction and worse prognosis.

  19. Nutrition Risk in Critically ill (NUTRIC) Score

    Time frame: First day of admission to the ICU

    The NUTRIC score is a screening tool designed to identify critically ill patients at high nutritional risk. It incorporates factors such as age, severity of illness, comorbidities, and inflammation to guide nutritional interventions in the intensive care unit (ICU).

    Unit of Measure: Score (0-10 scale) Interpretation: Higher scores indicate greater nutritional risk.

  20. Global Leadership Initiative on Malnutrition (GLIM) Criteria

    Time frame: First day of admission to the ICU

    The GLIM criteria provide a standardized framework to diagnose malnutrition based on a combination of phenotypic criteria (including weight loss, low BMI, and reduced muscle mass) and etiologic criteria (such as reduced food intake or disease burden/inflammation). These criteria are used across clinical settings to identify malnutrition and grade its severity.

    Unit of Measure: Categorical (e.g., malnutrition diagnosed: yes/no; severity graded as mild, moderate, or severe)

Sponsors and collaborators

Lead sponsor

Atılım University

Other

Registry information

Official study title

The Effect of Intermittent Feeding on Circadian Rhythm in Critical Illness

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Jul 14, 2025
Registry last updated
Oct 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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