Effect of Raised End-Tidal pCo2 on Choroidal Volume

This study is to investigate the relationship between arterial carbon dioxide (CO2) concentration and vitreous pressure on the choroidal volume by integrated intraoperative OCT imaging under eye exams under anesthesia.

Study Overview

• Status: Recruiting
• Conditions: Intraocular Pressure
• Intervention / Treatment: Other: Ventilation manipulation

Detailed Description

Children with normal eyes undergoing an exam under anesthesia or a non-intraocular eye procedure will have one eye examined after research consent is taken. Children have very elastic ocular tissues. When they are having an intraocular procedure positive vitreous pressure can cause the iris to prolapse out of the eye and this can cause intraoperative and postoperative complications. The causes of the positive vitreous pressure have been speculated to be due to an increase in choroidal volume. The Choroid is a layer of blood vessels sitting between the sclera and the retina. Ocular Coherence Tomography (OCT) is an imaging tool that allows an optical section of the retina, choroid and sclera to be examined. The subfoveal choroidal thickness has been shown to be a consistent area that can be measured with reliability that the anatomical site of measurement is consistent. By varying the end tidal CO2 the thickness of the choroid will be measured and at the same time the intraocular pressure taken using a pneumatonometer. The OCT is integrated into the operating microscope and is used to take a scan of the fovea. Three scans will be taken after 5minutes of the particular end tidal pCO2. In order to ensure the choroidal thickness is not being influenced by the axial length of the eye, the axial length will be measured using an ultrasound probe at the beginning of the measurements just once. In order to ensure that the position of the head and body is not influencing the choroidal thickness a spirit level will be used to ensure a flat operating bed at the beginning of the measurements.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Amy Monroe, MPH, MBA; Phone Number: 6382 412-623-6382; Email: monroeal@upmc.edu
• Study Contact Backup: Name: Alisha Maslanka, BS, CCRC; Phone Number: 2748 412-491-2748; Email: alisha.maslanka@chp.edu

Study Locations

• United States
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15224
      • Recruiting
      • University of Pittsburgh Medical Center
      • Contact: Amy Monroe, MPH, MBA; Email: monroeal@upmc.edu
      • Principal Investigator: Kanwal Nischal, MD,FRCOphth
      • Sub-Investigator: Lieu Tran, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• any child undergoing an eye exam under anesthesia for an ophthalmologic reason.
• children between the ages newborn to 8 years of age.

Exclusion Criteria:

• children who are not having an eye exam under anesthesia.
• * children over the age of 8 years of age.
• * children with altered cerebral autoregulation, or increased intracranial pressure, or any other condition deemed appropriate by the anesthesiologist.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Observational Group; Manipulation of end tidal carbon dioxide in subjects	Other: Ventilation manipulation; Effects of ventilation manipulation to achieve desired levels of end tidal carbon dioxide

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intraocular Pressure (IOP) (mmHg)	Measurement of intraocular pressure after maintenance of end tidal pCO2 for 5 minutes at three end tidal pCO2 values : 40mmHg, then 30mmHg and then 50mmHg	After induction of anesthesia end tidal CO2 will be manipulated to 40mmHg, then 30mmHg and then 50mmHg. The end tidal CO2 levels will be held for at least 5 minutes after each ventilation manipulation and at the end of this 5 minute period IOP measured

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Choroidal thickness ( microns)	After 5 minutes of maintenance of end tidal pCO2 at 40mmHg, then 30mmHg and then 50mmHg, ocular coherence tomography (OCT) will be used to capture the subfoveal choroid. The images of the choroid will be provided to blinded individuals who will measure their thickness using the integrated scale on the OCT image.	After induction of anesthesia end tidal CO2 will be manipulated to 40mmHg, then 30mmHg and then 50mmHg. The end tidal CO2 levels will be held for at least 5 minutes after each ventilation manipulation;at the end of 5 minute period choroid images taken

Collaborators and Investigators

• Sponsor: University of Pittsburgh
• Investigators: Study Director: Amy Monroe, MPH, MBA, University of Pittsburgh; Principal Investigator: Kanwal Nischal, MD,FRCOphth, University of Pittsburgh

Study record dates

Study Major Dates

• Study Start (Actual): February 27, 2023
• Primary Completion (Estimated): February 27, 2025
• Study Completion (Estimated): February 27, 2025

Study Registration Dates

• First Submitted: January 24, 2024
• First Submitted That Met QC Criteria: February 16, 2024
• First Posted (Estimated): February 23, 2024

Study Record Updates

• Last Update Posted (Estimated): February 23, 2024
• Last Update Submitted That Met QC Criteria: February 16, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Other Study ID Numbers: STUDY21100163

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