Preoperative Chronotype and Emergence Delirium in the Elderly

A Retrospective Study on the Impact of Preoperative Sleep Chronotype on Postoperative Emergence Delirium in Elderly Patients

Emergence delirium (ED) is a prevalent and severe postoperative complication in elderly surgical patients. It can occur at any perioperative stage but most frequently develops during or immediately after emergence from general anesthesia. Characterized by acute agitation and confusion, ED manifests as sharp declines in attention and cognitive function, accompanied by impaired consciousness and disorganized thinking. As a common adverse event in the early postoperative period, ED occurs in up to 87% of critically ill patients, 10%-24% of adult general medical patients, 37%-46% of anesthetized general surgical patients, with the highest incidence of 50% observed in elderly surgical patients during early recovery in the Post-Anesthesia Care Unit (PACU). Anesthesiologists have long attached great importance to the harmful effects of ED on clinical outcomes, as ED elevates risks of postoperative hemorrhage and physical trauma, extends PACU monitoring duration and hospital length of stay, and increases postoperative complications, mortality and medical resource consumption.

Chronotype describes the behavioral manifestation of the endogenous 24-hour circadian timing system. In mammals, circadian rhythms are maintained and regulated by a complete clock system: the central master clock resides in the suprachiasmatic nucleus (SCN) of the hypothalamus, while peripheral clocks exist in organs such as the liver, lungs and skeletal muscle. Patients with delirium commonly suffer severe circadian disturbances, which are embodied in disordered sleep-wake cycles, abnormal secretion rhythms of melatonin and cortisol, and altered expression of clock genes. Chronotypes are conventionally divided into morning, evening and intermediate types. Previous observational studies have proven that chronotype correlates with numerous disorders including metabolic diseases, psychiatric illnesses, brain function, delirium and cognitive performance. Accumulated evidence supports an association between delirium and circadian rhythms, and suggests that circadian dysfunction contributes to the pathological development of delirium.

Nevertheless, few studies have investigated how chronotype affects ED in elderly patients. This study intends to explore the correlation between chronotype and postoperative ED in elderly surgical patients and compare ED incidence among patients with distinct chronotypes. The results of this research will offer scientific references for formulating targeted preventive measures against ED in elderly populations, lower postoperative ED rates, alleviate adverse postoperative events, and optimize long-term clinical prognosis.

Study Overview

• Status: Completed
• Conditions: Emergence Delirium
• Intervention / Treatment: Other: the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)

• Study Type: Observational
• Enrollment (Actual): 235

Contacts and Locations

Study Locations

• China
  • Chongqing Municipality
    • Chongqing, Chongqing Municipality, China, 400010
      • The Second Affiliated Hospital of Chongqing Medical University

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

Researchers screened elderly inpatients scheduled to receive general anesthesia at The Second Affiliated Hospital of Chongqing Medical University from October 2024 to March 2025.

Description

Inclusion Criteria:

1. Age of 65 years or older.
2. Scheduled non-cardiac surgery under general anesthesia.
3. American Society of Anesthesiologists (ASA) physical status I-III.
4. Signed informed consent for surgical treatment.

Exclusion Criteria:

1. Auditory or verbal impairment.
2. Long-term use of psychotropic drugs or alcohol abuse.
3. Pre-existing psychiatric disease or cognitive dysfunction.
4. A medical history of cerebral infarction, dementia or hypoalbuminemia.

Withdrawal Criteria：

1. Surgery duration less than 60 minutes
2. Intraoperative blood transfusion
3. Intraoperative hypothermia or hypotension
4. Intraoperative administration of dexmedetomidine
5. Postoperative transfer to intensive care unit
6. Requirement for secondary surgical intervention

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
morning chronotype group; Patients with the Morningness-Eveningness Questionnaire Self-Assessment Version (MEQ-SA) scores ≥ 60	Other: the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU); Emergence delirium was assessed at 30 minutes after admission to the post-anesthesia care unit (PACU) and at PACU discharge using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), a validated tool with high sensitivity and specificity for delirium detection.sment Method for the Intensive Care Unit (CAM-ICU)
non-morning chronotype group; Patients with the Morningness-Eveningness Questionnaire Self-Assessment Version (MEQ-SA) scores < 60	Other: the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU); Emergence delirium was assessed at 30 minutes after admission to the post-anesthesia care unit (PACU) and at PACU discharge using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), a validated tool with high sensitivity and specificity for delirium detection.sment Method for the Intensive Care Unit (CAM-ICU)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of emergence delirium 1	Use CAM-ICU	At 30 minutes after post-anesthesia care unit admission
Incidence of emergence delirium 2	Use CAM-ICU	Within 5 minutes prior to post-anesthesia care unit discharge.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative CAM-ICU scores 1	Use CAM-ICU	At 30 minutes after post-anesthesia care unit admission
Postoperative CAM-ICU scores 2	Use CAM-ICU	Within 5 minutes prior to post-anesthesia care unit discharge.
Postoperative pain scores 1	Use the visual analogue scale（VAS）	At 30 minutes after post-anesthesia care unit admission
Postoperative pain scores 2	Use the visual analogue scale（VAS）	Within 5 minutes prior to post-anesthesia care unit discharge.
Hospital length of stay	The period from when the patients enter the hospital until they leave the hospital	Up to 12 weeks

Collaborators and Investigators

• Sponsor: The Second Affiliated Hospital of Chongqing Medical University

Study record dates

Study Major Dates

• Study Start (Actual): October 23, 2024
• Primary Completion (Actual): March 26, 2025
• Study Completion (Actual): March 30, 2025

Study Registration Dates

• First Submitted: July 15, 2026
• First Submitted That Met QC Criteria: July 21, 2026
• First Posted (Actual): July 23, 2026

Study Record Updates

• Last Update Posted (Actual): July 23, 2026
• Last Update Submitted That Met QC Criteria: July 21, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Elderly; Emergence Delirium; Sleep Chronotype
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Postoperative Complications; Pathologic Processes; Confusion; Neurobehavioral Manifestations; Neurocognitive Disorders; Delirium; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Emergence Delirium
• Other Study ID Numbers: NO. 2024-193

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