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Effect of Acetazolamide on Intraocular Pressure After Being in the Trendelenburg Position. (TaPPs)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT03107429
Recruitment Status : Completed
First Posted : April 11, 2017
Last Update Posted : April 11, 2017
Sponsor:
Information provided by (Responsible Party):
University of Nottingham

Tracking Information
First Submitted Date  ICMJE February 21, 2017
First Posted Date  ICMJE April 11, 2017
Last Update Posted Date April 11, 2017
Actual Study Start Date  ICMJE March 1, 2015
Actual Primary Completion Date October 1, 2015   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: April 4, 2017)
Comparison of IOP pressure during Trendelenburg position after placebo and acetazolamide at each given time point outlined in methods. [ Time Frame: 6 days. 2 Days involved in study (6 hours each) and a minimum of 5 days between study days to allow 'wash-out period' of drug. ]
IOP measurements will be taken at each described time point on both study days and the difference in IOP measurement after acetazolamide will be compared to those after placebo.
Original Primary Outcome Measures  ICMJE Same as current
Change History No Changes Posted
Current Secondary Outcome Measures  ICMJE Not Provided
Original Secondary Outcome Measures  ICMJE Not Provided
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE Effect of Acetazolamide on Intraocular Pressure After Being in the Trendelenburg Position.
Official Title  ICMJE A Pilot Crossover Study in Healthy Volunteers to Assess the Effect of Acetazolamide on Intraocular Pressure After Being in the Trendelenburg Position.
Brief Summary

Perioperative vision loss following laparoscopic colorectal surgery is rare but has been reported. Studies show Trendelenburg positioning during surgery can produce a significant rise in the IOP, and this rise is thought to be a possible factor. Acetazolamide decreases IOP by reducing the formation of aqueous humour.

Aims:

To investigate if acetazolamide reduces the IOP rise resulting from Trendelenburg positioning.

Methods:

A randomised cross-over blinded pilot study. Nine healthy volunteers were randomised to start with the placebo or Acetazolamide with a 5 days' washout period. Baseline IOP was measured on both days. After 1.5 hours of taking the medication, volunteers lay head-down at 17 degrees' for 4 hours and IOP measurements repeated. This reading was subtracted from the baseline to give a 'change in IOP'.

Detailed Description

Background:

Laparoscopic (keyhole) bowel surgery often requires positioning patients on the operating table in very steeply angled positions for up to four or more hours. There have been case reports of patients suffering cognitive impairment after surgery with long periods of Trendelenburg (person is lying flat at an incline where their head lies lower than their feet) positioning.

Evidence from other fields of surgery suggests that "head-down" positions can produce a significant rise in the intraocular pressure. Transient vision problems and loss of sight has been reported following surgery is rare instances, including one case after laparoscopic colorectal resection. The cause of this is not fully understood, but rises in intraocular pressure (IOP) has been suggested as a possible factor. This may be particularly relevant in patients who have pre-existing high baseline IOP as a result of glaucoma. Studies looking at the effect of Trendelenburg positioning have shown that there is an increase in IOP. This study is to assess the effect of acetazolamide on the IOP rise after being placed in the Trendelenburg position. Acetazolamide is a carbonic anhydrase inhibitor which is used to treat glaucoma. The drug works by decreasing aqueous humour formation. It can be given as eye drops (but the absorption of this is variable and therefore so is the effect), orally and intravenously. The oral dose can be given as a one off dose or a divided dose. Maximum onset of IOP reduction occurs 2 to 5 hours after taking an oral dose and duration is 6-8 hours.

Aims:

This study aims to investigate the effect of acetazolamide on the IOP rise whilst in the Trendelenburg position.

Experimental protocol and methods:

This will be a pilot randomised crossover study with 9 healthy volunteers recruited and randomised to either Group 1 or Group 2. Group 1 will start with the Control Day; Group 2 will start with the Intervention Day. On the Control Day, a baseline IOP using a Tonopen XL will be taken. They will then be placed in 17 degrees head-down position 2.5hours after a placebo is administered for a minimum of 1 hour and a maximum of 4 hours. Repeat IOP measure will be taken whilst in the Trendelenburg position after 5 minutes, and then every 30 minutes from the start of Trendelenburg position. On the Intervention Day, baseline IOP will be taken, they will then be 500mgs of acetazolamide. After 2.5 hours, the volunteers will then be placed in the Trendelenburg position at 17 degrees for position for a minimum of 1hour and a maximum of 4 hours. Repeat IOP measure will be taken whilst in the Trendelenburg position after 5 minutes, and then every 30 minutes from the start of Trendelenburg position.

Inclusion criteria:

Healthy volunteers, aged 18 and over

Exclusions criteria

Pregnancy Breast Feeding Hepatic impairment Patients with pre-existing conditions affecting IOP regulation eg Glaucoma, previous eye surgery Regular medication affecting IOP Under the age of 18 Refusal to give written informed consent

Measurable endpoints/ statistical power

Primary endpoint: Comparison of IOP pressure before and after being placed in the Trendelenburg position between the two days - Day 1 volunteers will be administered with a placebo before being placed in the Trendelenburg position and Day 2 after acetazolamide has been administered.

Power: Bucci et al compared the effect of oral acetazolamide on IOP on 22 patients. They detected a 3.7mmHg decrease in IOP after 2 hours. Using this study, we powered our study to require 18 patients.

Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Allocation: Randomized
Intervention Model: Crossover Assignment
Intervention Model Description:
A pilot blinded randomised cross-over study.
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Masking Description:

Placebo and Acetazolamide tablets were placed into capsules that were the same by the Pharmacy department. A separate investigator generated a randomisation list for 11 volunteers to decide if a placebo or acetazolamide will be taken on Day 1. They then created envelopes with the corresponding medication in Day 1 and the other in Day 2 and these were marked as Volunteer 1, 2, 3 etc. The randomisation list was sealed and kept with each investigator so they could be accessed if required due to any adverse events.

The volunteers will be recruited and both the investigators and the volunteers were blinded to what was received on each study day.

Primary Purpose: Prevention
Condition  ICMJE IOP
Intervention  ICMJE
  • Drug: Acetazolamide
    Acetazolamide tablets were placed in capsules to make them look similar to placebo.
    Other Name: Diamox
  • Drug: Placebo
    Placebo was a sugar based placebo placed in a capsule.
    Other Name: Placebo arm, Placebo and Trendelenburg.
  • Other: Trendelenburg Position
    Placed in Trendelenburg Position
Study Arms  ICMJE
  • Active Comparator: Placebo and Trendelenburg Position

    Volunteers received placebo medication and placed in Trendelenburg.

    IOP will be measured. Participants will then be administered with a placebo and after 2.5 hours will be placed in 17 degrees head-down position for a minimum of 1 hour and maximum 4 hours. Repeat IOP measure will be taken whilst still in the Trendelenburg position after 5 mins and then every 30 minutes.

    Interventions:
    • Drug: Placebo
    • Other: Trendelenburg Position
  • Experimental: Acetazolamide and Trendelenburg Position

    Volunteer given acetazolomide and placed in Trendelenburg position and IOP measured.

    IOP will be measured. Participants will then be administered with acetazolamide and after 2.5 hours placed in 17 degrees head-down position for a minimum of 1 hour and maximum 4 hours. Repeat IOP measure will be taken whilst still in the Trendelenburg position after 5 mins and then every 30 minutes.

    Interventions:
    • Drug: Acetazolamide
    • Other: Trendelenburg Position
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Completed
Actual Enrollment  ICMJE
 (submitted: April 4, 2017)
9
Original Actual Enrollment  ICMJE Same as current
Actual Study Completion Date  ICMJE October 1, 2015
Actual Primary Completion Date October 1, 2015   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • Healthy volunteers aged 18 and over

Exclusion Criteria:

  • Pregnancy
  • Breast Feeding
  • Hepatic impairment
  • Patients with pre-existing conditions affecting IOP regulation eg Glaucoma, previous eye surgery
  • Regular medication affecting IOP
  • Under the age of 18
  • Refusal to give written informed consent
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Not Provided
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT03107429
Other Study ID Numbers  ICMJE C12022015 SoM NDDC TaPPs
Has Data Monitoring Committee No
U.S. FDA-regulated Product
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
IPD Sharing Statement  ICMJE
Plan to Share IPD: No
Responsible Party University of Nottingham
Study Sponsor  ICMJE University of Nottingham
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Parveen Vitish-Sharma, MRCS MSc NDDC BRU
PRS Account University of Nottingham
Verification Date April 2017

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP