Anaesthetic protocol for paediatric glaucoma examinations: the prospective EyeBIS Study protocol

Abstract

Introduction: Neonates and young infants with diagnosed or highly suspected glaucoma require an examination under anaesthesia to achieve accurate intraocular pressure (IOP) measurements, since crying or squinting of the eyes may increase IOP and lead to falsely high values. IOP considerably depends on perioperative variables such as haemodynamic factors, anaesthetics, depth of anaesthesia and airway management. The aim of this paper is to report the design and baseline characteristics of EyeBIS, which is a study to develop a standardised anaesthetic protocol for the measurement of IOP under anaesthesia in childhood glaucoma, by investigating the link between the magnitude of IOP and depth of anaesthesia.

Methods and analysis: This is a single-centre, prospective cohort study in 100 children with diagnosed or highly suspected glaucoma all undergoing ophthalmological examination under general anaesthesia. 20 children, who undergo general anaesthesia for other reasons, are included as controls. The primary outcome measure is the establishment of a standardised anaesthetic protocol for IOP measurement in childhood glaucoma by assessing the relationship between IOP and depth of anaesthesia (calculated as an electroencephalography variable, the bispectral index), with special emphasis on airway management and haemodynamic parameters. The dependence of IOP under anaesthesia on airway management and haemodynamic parameters will be described, using a mixed linear model. Restricting the model to patients with healthy eyes will allow to determine a 95% reference region, in which 95% of the measurement values of patients with healthy eyes can be expected.

Ethics and dissemination: The study has been approved by the local ethics committee of the Medical Association of Rhineland-Palatine (Ethik-Kommisssion der Landesaerztekammer Rheinland-Pfalz), Germany (approval number: 2019-14207). This work will be disseminated by publication of peer-reviewed manuscripts, presentation in abstract form at national and international scientific meetings and data sharing with other investigators.

Trial registration number: ClinicalTrials.gov Registry (NCT03972852).

Keywords: anaesthesia in ophthalmology; glaucoma; paediatric anaesthesia; paediatric ophthalmology.

Conflict of interest statement

Competing interests: None declared.

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Study flow chart according to the American Society of Anesthesiologists (ASA) with inclusion and exclusion criteria, as well as outcome measures.

Figure 2

Schedule of study enrolment and interventions. BIS, bispectral index; IOP, intraocular pressure; i.v., intravenous; SpO2, oxygen saturation.

Figure 3

EyeBIS worksheet. Detailed layout of all steps on the interventional time scale. BIS, bispectral index; etCO2, end tidal carbon dioxide; FiO2, fractional inspired oxygen; HR, heart rate; IOP, intraocular pressure; i.v., intravenous; PEEP, Positive End-Expiratory Pressure; Pinsp, Inspiratory pressure; RR, blood pressure; SpO2. oxygen saturation; TIVA, total intravenous anaesthesia; VT, tidal volume.