Intraocular Pressure, Optic Nerve Sheath Diameter and Optic Perfusion Pressure of Minimal Low and High-Flow Anesthesia

Not Applicable

Not yet recruiting

• Conditions: Anesthesia; Intraocular Pressure; Nephrolithiasis

• Registration Number: NCT06684704
• Lead Sponsor: Elazıg Fethi Sekin Sehir Hastanesi

Brief Summary

The aim of this clinical trial is to determine the effect of minimal low-flow versus high-flow anesthesia on intraocular pressure (IOP) by non-contact tonometry, optic nerve sheath diameter (ONSD) by USG and optic perfusion pressure (OPP) in percutaneous nephrolithotomy operations. He will also learn about the effect on hemodynamic responses and arterial oxygenation. The main questions it aims to answer are:

What are the effects of low-flow anesthesia combined with prone position on intraocular pressure (IOP), optic nerve sheath diameter (ONSD) and optic perfusion pressure (OPP)? Which anesthesia flow type has optimal eye-protective results? The investigators will compare minimal low-flow and high-flow anesthesia.

Participants:

The study will include patients between the ages of 18-60 years with ASA (American Society of Anesthesiologists) risk classification I-II-III, who are scheduled for unilateral percutaneous nephrolithotomy (PCNL) operation in the Urology Clinic under elective conditions and who have given informed consent.

Detailed Description

Today, rapidly depleting resources and deteriorating ecosystems bring the concept of sustainability to the forefront in all areas. Anesthesia applications have also become an important evaluation subject in terms of sustainability. One of the important components of sustainable anesthesia is low-flow anesthesia. Low-flow anesthesia technique is a technique based on the re-breathing of at least half of the gas exhaled in semi-closed systems by returning at least half of the exhaled gas to the patient in the next inspiration (1). This reduces anesthetic gas consumption, reduces the carbon footprint and prevents environmental pollution. In addition, low-flow anesthesia protects mucociliary clearance mechanisms by preventing airway moisture loss and supports the physiological balance of the respiratory system (2). With the widespread use of low-flow anesthesia, research on the systemic effects of this method compared to high-flow anesthesia has also increased. Prone position may lead to undesirable effects such as increased intracranial pressure, increased intraocular pressure, increased cerebral blood flow and atelectasis. Although the effects of this position on intracranial and intraocular pressure are well known, studies on the effect of low-flow anesthesia on these parameters are limited. Therefore, how the use of low-flow anesthesia in combination with the prone position changes these effects should be evaluated in larger-scale studies (3).

Study Timeline

• Status Verified: 2024-11
• Study First Submitted: 2024-11-09
• Study First Submitted QC: 2024-11-09
• Study First Posted: 2024-11-12
• Study Start: 2025-02-17
• Last Update Submitted: 2025-02-17
• Last Update Posted: 2025-02-18
• Primary Completion: 2025-02-27
• Study Completion: 2025-03-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 60

Inclusion Criteria

• Patients aged 18-60 years
• ASA (American Society of Anesthesiologists) risk classification I-II-III
• Unilateral percutaneous nephrolithotomy (PCNL) operation

Exclusion Criteria

• Patients with drug and alcohol addiction,
• long-term smoking history (at least 1 pack/1 year),
• BMI>35,
• chronic lung disease,
• cerebrovascular disease,
• severe systemic diseases such as kidney, liver or advanced heart failure .

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Optic nerve sheath diameter (ONSD) measurements	Measurements will be performed serially after induction of anesthesia (T0), 1 min after intubation (T1), 30 min after supine position (T2), supine from prone position (T3) and 5 min after extubation (T4).	ONSD measurement bedside ultrasonography (POCUS) will be performed in accordance with the standardized ONSD POCUS Quality Criteria Checklist (ONSD POCUS QCC)

Secondary Outcome Measures

Name	Time	Method
Intraocular pressure (IOP)	Measurements will be performed serially after induction of anesthesia (T0), 1 min after intubation (T1), 30 min after supine position (T2), supine from prone position (T3) and 5 min after extubation (T4).	Intraocular pressure (IOP) is calculated by spraying air into the center of the cornea with a noncontact tonometer and measuring the reflected air again by slightly flattening the cornea.

Trial Locations

Locations (1)

Elazığ Fethi Sekin City Hospital; 🇹🇷 Elazığ, Seçiniz, Turkey