Effects of Different Types of General Anesthesia on Postoperative Pupillary Reactivity

Medical University of Vienna

Status: Enrolling

Conditions: Pupillary Reflex Impaired

Treatments: Diagnostic Test: Alertness testing; Procedure: Propofol anesthesia; Procedure: Sevoflurane anesthesia; Diagnostic Test: PLR

Study type: Interventional

Funder types: Other

Identifiers

NCT04307238

1520/2019

Details and patient eligibility

About

Objective: To compare the effects of volatile and intravenous anesthetics on pupillary function after general anesthesia using a portable infrared pupillometer.

Design: A monocentric, prospective, double blinded randomized study.

Patients: Patients who require elective Ear, Nose and Throat (ENT) surgery under general anesthesia.

Interventions: Patients undergoing elective ENT surgery will be assigned to intravenous versus inhalative anesthesia and pupillometric parameters monitored postoperative, using an infrared pupillometer.

Outcomes measures: Reported pupillometric parameters after intravenous and inhalative anesthesia.

The purpose of this study is to compare general anesthesia techniques (volatile, intravenous) on postoperative changes in pupillary reactivity by using infrared pupillometry.

Full description

Introduction: With the increased focus on early discharge after surgery and anesthesia, it is important to identify objective criteria that can be used to assess home-readiness after ambulatory surgery. Premature discharge may lead to a higher rate of patients suffering complications and to an increased readmission rate. Time-consuming objective evaluations of postoperative vigilance status like EEG registrations are not practicable in routine postoperative clinical practice.

In this study an approach to a more quantitative judgment of postoperative vigilance and consciousness is made by recording pupillometric measurements using a portable infrared pupillometer. The findings of this study may provide new important insights to the meaning of pupillary responses for postoperative vigilance measurement.

Aim: With regard to the lack of knowledge about mechanisms that enable the central nervous system to restore consciousness after the deep functional disorder of the anesthetized state, this study aims to compare general anesthesia techniques (volatile, intravenous) on postoperative changes in pupillary reactivity by using infrared pupillometry.

The primary aim of this study is to investigate changes in pupillary reactivity (pupillary light reflex (PLR, %) in the early postoperative phase (2 hours) after common used types of general anesthesia techniques (inhaled - sevoflurane versus intravenous - propofol).

Secondary aim is to examine whether decreased postoperative PLR predicts a decline in neuropsychological testing (alertness).

Hypotheses: The investigators hypothesis that changes in PLR within the first 2 postoperative hours differs depending on the anesthesia technique used, with a lower decline in PLR after propofol compared to sevoflurane anesthesia.

Furthermore, the investigators hypothesis that postoperative PLR correlates with changes in alertness measured by a neuropsychological test.

Design: This study will be a prospective, randomized double blinded study.

Methods: The study is approved by the local ethics committee and written informed consent will be obtained from each patient. A total of 108 patients aged ≥18 and ≤99 years, with American Society of Anesthesiologist (ASA) physical status scores I-II, scheduled for elective ENT surgery will be enrolled. Baseline assessment of pupillometry and neuropsychological test will be carried out before surgery (baseline) and at predefined time intervals during the first 2 postoperative hours after the end of anesthesia. Results (AUC, PLR%) will be compared between both anesthesia groups.

Primary outcome parameter will be the AUC of PLR (percentage change, %) measured every 15 minutes during the first 2 postoperative hours. Secondary outcome parameter will include the neuropsychological test score (Digit Symbol Substitution Test (DSST), the Visual Intrinsic Alertness Test (VIA) and the Trail making Test (TMT)) will be performed every 30 minutes after general anesthesia (sevoflurane, propofol maintained).), assessed every 30 min up to 2 hours after discontinuation of anesthesia.

Enrollment: 108 estimated patients

Sex: All

Ages: 18 to 99 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients aged ≥ 18 and ≤99 years
• ASA I-II
• Patients undergoing elective ENT surgery under general anesthesia

Exclusion criteria

• Patients aged < 18 and >99 years
• consumption of antidepressants, tranquilizer, psychotropic medications
• history of mental illness, neurosurgery, neurological or psychiatric disease
• ophthalmologic disease
• preexisting cognitive impairment
• Patients with drug dependence, alcoholism
• the patients' inability to follow procedures
• implanted electronic medical devices

Trial design

Primary purpose: Supportive Care

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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108 participants in 2 patient groups

Propofol group

Other group

Description:

General anesthesia will be maintained by continually intravenous administered propofol.

Treatment:

Diagnostic Test: PLR

Procedure: Propofol anesthesia

Diagnostic Test: Alertness testing

Sevoflurane Group

Other group

Description:

General anesthesia will be maintained by inhalative administered sevoflurane.

Treatment:

Diagnostic Test: PLR

Procedure: Sevoflurane anesthesia

Diagnostic Test: Alertness testing