Optic Nerve Sheath Diameter Changes During Bariatric Surgery

Fatih Sultan Mehmet Training and Research Hospital58 enrolled

Overview

This prospective clinical study aimed to evaluate the effects of pneumoperitoneum and patient positioning on intracranial pressure in patients undergoing bariatric surgery. Intracranial pressure was assessed noninvasively using ultrasonographic optic nerve sheath diameter (ONSD) measurements. ONSD measurements were performed before anesthesia induction in the supine position (T0), 5 minutes after anesthesia induction (T1), 5 minutes after creation of pneumoperitoneum and placement in the reverse Trendelenburg position (T2), at the 20th minute of pneumoperitoneum (T3), and 5 minutes after termination of pneumoperitoneum and return to the supine position (T4). The study aimed to determine the effects of anesthesia, pneumoperitoneum, and surgical positioning on intracranial pressure during bariatric surgery

Obesity and bariatric surgery are associated with physiological changes that may influence intracranial pressure. Pneumoperitoneum and reverse Trendelenburg positioning, commonly used during laparoscopic bariatric surgery, can affect venous return, respiratory mechanics, and cerebral hemodynamics. Ultrasonographic measurement of optic nerve sheath diameter (ONSD) is a noninvasive and reliable method for estimating changes in intracranial pressure. The aim of this prospective clinical study was to investigate the effects of anesthesia induction, pneumoperitoneum, and patient positioning on intracranial pressure in patients undergoing bariatric surgery. ONSD measurements were obtained at five predefined time points: before anesthesia induction in the supine position (T0), 5 minutes after anesthesia induction (T1), 5 minutes after creation of pneumoperitoneum and placement in the reverse Trendelenburg position (T2), at the 20th minute of pneumoperitoneum (T3), and 5 minutes after termination of pneumoperitoneum and return to the supine position (T4). Hemodynamic parameters, end-tidal carbon dioxide levels, peak airway pressure, and plateau airway pressure were recorded simultaneously. The primary outcome was the change in ONSD measurements during different stages of the surgical procedure. The study sought to determine whether pneumoperitoneum and patient positioning contribute to changes in intracranial pressure during bariatric surgery.

Study Type

OBSERVATIONAL

Enrollment

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Patients scheduled for bariatric surgery. 2. ASA physical status 1-3 3. Patients aged 18 years and older Exclusion Criteria: 1. Patients who declined to participate. 2. Age \<18 years. 3. ASA physical status IV. 4. Previous cataract surgery. 5. Presence of conditions associated with increased intracranial pressure, including hydrocephalus, cerebrovascular disease, or intracranial tumors. 6. Ocular conditions that could interfere with optic nerve sheath diameter measurement, including globe pathology or glaucoma

Outcomes

Primary Outcomes

Optic Nerve Sheath Diameter (ONSD) at T0

ONSD was measured by ultrasonography before induction of anesthesia ,with the patient awake and in the supin position.ONSD was recorded in millimeters(mm)

Time frame: within 5 minutes before induction of anesthesia (T0)

optic nerve sheath diameter (ONSD) T1

ONSD measured by ultrasonography 5 minutes after induction of anesthesia ,with the patient in the supin position.ONSD will be reported in millimeters(mm)

Time frame: 5 minutes after induction of anesthesia (T1)

Optic Nerve Sheath Diameter (ONSD) at T2

ONSD measured by ultrasonography 5 minutes after pneumoperitoneum and positioning in reverse Trendelenburg. ONSD will be reported in millimeters (mm).

Time frame: 5 minutes after pneumoperitoneum and reverse Trendelenburg positioning (T2)

Optic Nerve Sheath Diameter (ONSD) at T3

ONSD measured by ultrasonography 20 minutes after pneumoperitoneum while maintaining the reverse Trendelenburg position. ONSD will be reported in millimeters (mm).

Time frame: 20 minutes after establishment of pneumoperitoneum in the reverse trendelenburg position (T3)

Optic Nerve Sheath Diameter (ONSD) at T4

ONSD measured by ultrasonography 5 minutes after termination of pneumoperitoneum and return to the supine position. ONSD will be reported in millimeters (mm).

Time frame: 5 minutes after termination of pneumoperitoneum and return to the supine position (T4)

Secondary Outcomes

changes in hemodynamic and respiratory parameters

Hemodynamic and respiratory parameters, including systolic, diastolic and mean arterial blood pressure, heart rate, peripheral oxygen saturation (SpO₂), end-tidal carbon dioxide (EtCO₂), peak airway pressure (Ppeak), and plateau airway pressure (Pplateau), were recorded at predefined perioperative time points and evaluated in relation to changes in optic nerve sheath diameter (ONSD).

Time frame: from within 5 minutes before induction of anesthesia (T0) to 5 minutes after termination of pneumoperitoneum and return to the supine position (T4).

Optic Nerve Sheath Diameter Changes During Bariatric Surgery

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes