IOPTaPPsNCT03107429
Effect of Acetazolamide on Intraocular Pressure After Being in the Trendelenburg Position.
A study testing Acetazolamide and Trendelenburg Position in people with IOP, run by University of Nottingham.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- IOP
- What is being tested?
- Acetazolamide and Trendelenburg Position
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 9 participants
- Where
- No sites listed yet
- Study dates
- 1 Mar 2015to 1 Oct 2015
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy volunteers aged 18 and over
Who cannot join
- 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
About this study
Official title: A Pilot Crossover Study in Healthy Volunteers to Assess the Effect of Acetazolamide on Intraocular Pressure After Being in the Trendelenburg Position.
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:
Read more
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'.
Read the 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.
- Conditions
- IOP
- Being tested
- Acetazolamide, Placebo, Trendelenburg Position
- Keywords
- Trendelenburg, Laparoscopic colorectal surgery, POVL
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AcetazolamideDrug
Also called Diamox
Acetazolamide tablets were placed in capsules to make them look similar to placebo.
PlaceboDrug
Also called Placebo arm, Placebo and Trendelenburg.
Placebo was a sugar based placebo placed in a capsule.
Trendelenburg PositionOther
Placed in Trendelenburg Position
| Study group | Role | What they receive |
|---|---|---|
| Placebo and Trendelenburg Position | Active comparator | 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. Receives: Drug: Placebo; Other: Trendelenburg Position |
| Acetazolamide and Trendelenburg Position | Experimental | 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. Receives: Drug: Acetazolamide; Other: Trendelenburg Position |
What is being measured
The primary outcome is the main question the study is designed to answer.
Comparison of IOP pressure during Trendelenburg position after placebo and acetazolamide at each given time point outlined in methods.
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.
Measured: 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.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Apr 2017
- Study start1 Mar 2015
- Primary completion1 Oct 2015
- Study completion1 Oct 2015
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for IOPStudies of the same condition, open and under way.
- More trials run by University of NottinghamThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- A pilot blinded randomised cross-over study.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 9 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Nottingham
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Parveen Vitish-Sharma, MRCS MSc, Principal investigator, NDDC BRU
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03107429
- Sponsor's protocol ID
- C12022015 SoM NDDC TaPPs
- Acronym
- TaPPs
- Status last verified
- Apr 2017
- First submitted
- 21 Feb 2017
- Last updated
- 11 Apr 2017
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 11 Apr 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Pilot Crossover Study in Healthy Volunteers to Assess the Effect of Acetazolamide on Intraocular Pressure After Being in the Trendelenburg Position.
- ClinicalTrials.gov ID
- NCT03107429
- Acronym / sponsor ID
- TaPPs / C12022015 SoM NDDC TaPPs
- Conditions
- IOP
- Keywords
- Trendelenburg, Laparoscopic colorectal surgery, POVL
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 9 participants (actual)
- Lead sponsor
- University of NottinghamUniversity, hospital or other
- Study start
- 1 Mar 2015 (actual)
- Primary completion
- 1 Oct 2015 (actual)
- Study completion
- 1 Oct 2015 (actual)
- First posted
- 11 Apr 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- A pilot blinded randomised cross-over study.
| Arm | Type | Receives |
|---|---|---|
| Placebo and Trendelenburg Position | Active comparator | Drug: Placebo, Other: Trendelenburg PositionVolunteers 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. |
| Acetazolamide and Trendelenburg Position | Experimental | Drug: Acetazolamide, Other: Trendelenburg PositionVolunteer 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Healthy volunteers aged 18 and over
Key exclusion criteria (7 listed)
- Pregnancy
- Breast Feeding
- Hepatic impairment
- Patients with pre-existing conditions affecting IOP regulation eg Glaucoma, previous eye surgery
- Regular medication affecting IOP
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| AcetazolamideAlso: DiamoxAcetazolamide tablets were placed in capsules to make them look similar to placebo. | Drug | Acetazolamide and Trendelenburg Position |
| PlaceboAlso: Placebo arm, Placebo and Trendelenburg.Placebo was a sugar based placebo placed in a capsule. | Drug | Placebo and Trendelenburg Position |
| Trendelenburg PositionPlaced in Trendelenburg Position | Other | Acetazolamide and Trendelenburg Position, Placebo and Trendelenburg Position |
Primary outcome
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.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Apr 2017.
- Individual participant dataSharing planned: No
Related trials for IOP
Active, not recruiting
Effect of IOP Lowering on Progressive HM
High Myopia, Intraocular Pressure
RecruitingPhase 2
A Phase 2a Study Comparing the Efficacy, Safety and Tolerability of Pregabalin Eye Drops Comparing With Timolol Eye Drops in Adults With Glaucoma or High Eye Pressure.
Primary Open - Angle Glaucoma (POAG), Ocular Hypertension (OHT)
Not yet recruiting
Glaucoma Drop Aids Part 2
Glaucoma, Intraocular Pressure
RecruitingPhase 4
Adaptive Optics OCT Evaluation of Rhopressa's Effects on the Retinal Ganglion Cells in Glaucoma Patients
Open Angle Glaucoma (OAG), Glaucoma
Not yet recruitingPhase 4
Iopidine to Decrease Intraocular Pressure Rise After Injections
Macular Degeneration, Diabetic Retinopathy
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Parveen Vitish-Sharma, MRCS MSc principal investigator
NDDC BRU
Questions about this trial
What is this clinical trial studying?
A study testing Acetazolamide and Trendelenburg Position in people with IOP, run by University of Nottingham.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 11 Apr 2017. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Apr 2017.