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NCT Number: NCT03988868

The Effect of End-tidal Carbon Dioxide Level on the Optic Nerve Sheath Diameter in Pediatric Patients

Because the optic nerve is surrounded by the cerebrospinal fluid, increase / decrease in the intracranial pressure can be examined by an increase / decrease in the optic nerve sheath diameter (ONSD). Non-invasive trans-orbital ultrasonography has been used to measure the ONSD and shown to be useful in differentiating patients with increased intracranial pressure (> 20 cmH2O).

Arterial carbon dioxide partial pressure (PaCO2) is closely related to cerebral blood flow. According to the textbook, an increase in PaCO2 in the range of PaCO2 = 25 mmHg to PaCO2 = 75 mmHg can cause a change in intracranial pressure by proportionally increasing cerebral blood flow. Because end-tidal CO2 partial pressure (ETCO2) reflects PaCO2, a significant correlation may be expected between the ETCO2 and the ONSD.

Previous studies in adult patients showed that ONSD was sensitively increased / decreased according to short-term hypercapnia (ETCO2 = 50mmHg) or hypocapnia (ETCO2 = 30mmHg) for 10 minutes and normalized at normal ETCO2 (40mmHg). Therefore, the reactivity of the ONSD according to the change of the ETCO2 was confirmed in adult patients.

In normal pediatric patients, ONSD is expected to respond to changes in ETCO2. However, no previous study has confirmed this. In addition, the reactivity of ONSD was not studied in neonates and infants with open fontanelle.

In this study, the investigators will performed trans-orbital ultrasonography in pediatric patients with normal intracranial intracranial pressure aged 18 years or younger scheduled for surgery under general anesthesia. The ONSD will be measured at three ETCO2 levels; 35mmHg, 40mmHg, and 45mmHg.

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Key information

Conditions

Anesthesia, General

Age range

Up to 18 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Seoul National University Hospital

Seoul, 03080, South Korea

About this study

Induction of general anesthesia and endotracheal intubation will be performed with standard electrocardiography, non-invasive blood pressure, heart rate, pulse oximetry, and ETCO2 monitoring.

The ONSD will be measured at three different ETCO2 levels (35mmHg, 40mmHg, and 45mmHg). Each ETCO2 levels will be maintained within +-2mmHg for 3 minutes.

A high frequency linear probe will be used to get the images of optic nerve sheath and the diameter (ONSD) will be measured at 3 mm from the papillary segment in the transverse plane. Mean arterial pressure and heart rate will be recorded during ONSD measurements. The open or closure of Fontanelle will be examined after ONSD measurements.

The ONSD and OND measurements will be performed by two independent researchers who do not participate in ultrasound examination using stored images.

Who can participate

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Children under 18 years of age who are under general anesthesia
  • Mechanical ventilation by endotracheal intubation
  • Supine position during surgery

Exclusion criteria

  • Disease including eyeball or orbit
  • Infection or trauma around the eyes
  • Difficult to access the eyes during surgery (Ophthalmologic surgery, neurosurgery, otorhinolaryngology surgery, etc.)
  • Patients with abnormal intracranial pressure abnormality (trauma, brain tumors, hydrocephalus, intracranial pressure control shunt, craniosynostosis..)
  • Laparoscopic surgery, Thoracoscopic surgery
  • Cerebrovascular disease such as Moyamoya disease
  • Hypotension
  • Atelectasis, pneumothorax, pleural effusion, pneumonia, wheezing or crackle before surgery
  • History of adverse reaction to ultrasound gel or Tegaderm (3M Canada, London, Ont., Canada) for eyeball protection

Treatment and study plan

Primary outcomes

  1. Optic nerve sheath diameter

    Time frame: 1 weeks

    Optic nerve sheath diameter (ONSD) measured at three ETCO2 levels(35mmHg, 40mmHg, and 45mmHg) by transorbital ultrasonography

Secondary outcomes

  1. Mean arterial pressure

    Time frame: 1 weeks

    Mean arterial pressure during ONSD measurements

  2. Heart rate

    Time frame: 1 weeks

    Heart rate during ONSD measurements

  3. Eyeball diameter

    Time frame: 1 weeks

    Eyeball diameter by transorbital ultrasonography

  4. Open Fontanelle

    Time frame: 1 weeks

    Open of the Fontanelle by palpation

  5. Age

    Time frame: 1 weeks

    Age

  6. Sex

    Time frame: 1 weeks

    Sex

  7. Weight

    Time frame: 1 weeks

    Weight

  8. Height

    Time frame: 1 weeks

    Height

  9. BMI

    Time frame: 1 weeks

    BMI

Sponsors and collaborators

Lead sponsor

Seoul National University Hospital

Other

Registry information

Official study title

The Effect of End-tidal Carbon Dioxide Level on the Optic Nerve Sheath Diameter Measured by a Transorbital Ultrasonography in Pediatric Patients

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Jun 18, 2019
Registry last updated
Dec 28, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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