The Application of Ultrasonic Measurement of Optic Nerve Sheath Diameter in Liposuction Surgery

The main purpose of this study is to investigate the effect of changes in Optic Nerve Sheath Diameter (ONSD) measured at different operating position during Liposuction Surgery.

Optic nerve sheath diameter (ONSD) has been shown to be a noninvasive indicator for monitoring intracranial pressure changes.

The use of anesthetic drugs will reduce the intracranial pressure. However, prone position and large fluid infusion can still lead to increased intracranial pressure.

The investigators hypothesized that during sedation and analgesia anesthesia, patients in prone position had higher ONSD.

Study Overview

• Status: Completed
• Conditions: Optic Nerve Sheath Diameter

Detailed Description

Liposuction is a common type of surgery in plastic surgery. In this type of surgery, the position is often changed from prone to supine. Different surgical positions, especially excessive flexion or rotation of the neck, can cause compression of the internal jugular vein, resulting in blocked cerebral venous return and resulting in increased intracranial pressure. Sedation and analgesia anesthesia are often used in liposuction surgery to provide the patient with an appropriate depth of anesthesia, preserve the patient's independent breathing, and can wake the patient during the operation to complete the position switch independently. Dexmedetomidine is a commonly used drug for sedation and analgesia anesthesia. Studies have reported that dexmedetomidine can be used to control intracranial pressure in special surgical positions by reducing cerebral metabolic rate, maintaining cerebral oxygen supply and demand balance, shrinking cerebral vessels and other functions.

Other studies have suggested that IOP increases during prone anesthesia, despite the effect of anesthetic drugs on lowering IOP. IOP, choroidal thickness, and optic nerve diameter also increased in normally awake patients in prone position. Optic nerve sheath diameter (ONSD) has been shown to be a noninvasive indicator of intracranial pressure changes and an independent factor of mortality, poor prognosis, and severity of traumatic brain injury. ONSD measurement is often used in laparoscopic surgery under general anesthesia to observe the effect of elevated CO2 in pneumoperitoneum on IOP. The changes of intracranial pressure were evaluated by ONSD when the head was low and the feet were high.

At present, there are no studies to observe the change of ONSD at different positions during Liposuction Surgery with sedation and analgesia.

The investigators hypothesized that during sedation and analgesia anesthesia, patients in prone position had higher ONSD.

This is an observational study. They were divided into two groups according to the operation, prone group and supine group.T0 awake, T1 30min after sedation and analgesia, T2 30 minutes after T1， T3 end of the operation. Record Optic nerve sheath diameter (ONSD), carotid artery flow rate, Bispectral index (BIS), liposuction swelling fluid input, infusion volume, end-expiratory carbon dioxide, mean arterial pressure, heart rate, peripheral oxygen saturation, body temperature and respiratory rate. Statistically significant differences were assessed.

The incidence of headache, nausea, vomiting and delirium were observed within 24 hours after operation.

• Study Type: Observational
• Enrollment (Actual): 55

Contacts and Locations

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100144
      • Xu Wenli

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

Female patients who will undergo liposuction surgery under sedation and sedative anesthesia. Fat suction areas can be the abdomen, lower back, limbs and other parts.

Description

Inclusion Criteria:

• Patients aged 18-50 years, undergoing liposuction surgery.
• American Society of Anesthesiologists (ASA) physical status Ⅰ and Ⅱ.
• Voluntary participation and signed an informed consent form.

Exclusion Criteria:

• Uncontrolled hypertension, diabetes.
• High nearsightedness or farsightedness, recent eye surgery, and other conditions in which ONSD cannot be measured.
• Moderate to severe obstructive sleep apnea syndrome was present before surgery.
• History of severe mental or neurological diseases, drug or psychotropic drug abuse.
• Cognitive dysfunction or inability to communicate.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Prone position group; Sedation and analgesia anesthesia will be administered after the prone position. All patients will receive standardized sedation and analgesia anesthesia with 1ug/kg sufentanil，1ug/kg/h dexmedetomidine，1mg/h midazolam，0.05-0.1ug/kg/min remifentanil. And adjust the drug speed according to the patient's respiratory rate, BIS changes. Optic nerve sheath diameter (ONSD), carotid artery flow rate, Bispectral index (BIS), liposuction swelling fluid input, infusion volume, end-expiratory carbon dioxide, mean arterial pressure, heart rate, peripheral oxygen saturation, body temperature and respiratory rate will be measured at four time points respectively.
Supine group; Sedation and analgesia anesthesia will be administered after the supine position. All patients will receive standardized sedation and analgesia anesthesia with 1ug/kg sufentanil，1ug/kg/h dexmedetomidine，1mg/h midazolam，0.05-0.1ug/kg/min remifentanil. And adjust the drug speed according to the patient's respiratory rate, BIS changes. Optic nerve sheath diameter (ONSD), carotid artery flow rate, Bispectral index (BIS), liposuction swelling fluid input, infusion volume, end-expiratory carbon dioxide, mean arterial pressure, heart rate, peripheral oxygen saturation, body temperature and respiratory rate will be measured at four time points respectively.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Optic nerve sheath diameter	Optic nerve sheath diameter under Ultrasonic measurement	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Carotid artery flow rate	Peak systolic velocity (PSV), End-diastolic blood flow velocity (EDV) under Ultrasonic measurement	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Carotid artery width	Carotid artery flow rate under Ultrasonic measurement	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Bispectral index (BIS)	Anesthesia depth measurement. 50-70 means appropriate level of sedation	30min and 60min after sedative AND analgesic anaesthesia, end of surgery
OAA/S score	Observer's assessment alert/Sedation. 1-5, 2-3 means a better outcome	30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Liposuction swelling fluid input	Amount of swelling anesthetic injected into fat suction area	30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Infusion volume	Intraoperative intravenous fluid infusion	30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Urine volume	Intraoperative urine drainage	30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Systolic blood pressure (SBP)	Intraoperative hemodynamics	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Diastolic blood pressure (DBP)	Intraoperative hemodynamics	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Mean blood pressure (MBP)	Intraoperative hemodynamics	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Heart rate (HR)	Intraoperative hemodynamics	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Saturation of Peripheral Oxygen (SPO2)	Intraoperative vital signs	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
body temperature (T)	Intraoperative vital signs	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
The partial pressure of end-tidal carbon dioxide (PetCO2)	Respiratory monitoring during surgery	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
respiratory rate (RR)	Respiratory monitoring during surgery	Enter the operating room, 30min and 60min after sedative AND analgesic anaesthesia, end of surgery
Postoperative adverse events	Number of Participants with postoperativ headache, nausea AND vomiting (PONV)	Day 1 after surgery

Collaborators and Investigators

• Sponsor: The Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College
• Investigators: Study Chair: Dong Yang, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and PekingUnion Medical College

Study record dates

Study Major Dates

• Study Start (Actual): November 19, 2024
• Primary Completion (Actual): May 25, 2025
• Study Completion (Actual): May 26, 2025

Study Registration Dates

• First Submitted: November 7, 2024
• First Submitted That Met QC Criteria: November 10, 2024
• First Posted (Actual): November 13, 2024

Study Record Updates

• Last Update Posted (Estimated): September 30, 2025
• Last Update Submitted That Met QC Criteria: September 29, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Optic nerve sheath diameter; Sedation and analgesia anesthesia; Liposuction surgery
• Other Study ID Numbers: ZX2024310

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No