Test of Chamber Pressure to Divers and Chamber Attendants

NCT ID: NCT01430325

Last Updated: 2013-02-15

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 42 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2011-07-31
• Study Completion Date: 2011-10-31

Brief Summary

SCUBA divers and chamber inside attendants will undergo a brief hyperbaric chamber excursion and will be asked to what chamber pressure they were compressed and what gas they breathed.

Detailed Description

In clinical trials evaluating hyperbaric oxygen, blinding can be challenging. Options for participant blinding include offering regular air at a lower pressure than the hyperbaric oxygen intervention, or compressing all participants to the same pressure but providing different gas mixes to the active and sham arms.

In some trials of hyperbaric oxygen for brain injury, investigators offer a sham chamber session (regular air at 1.2 atmospheres absolute [atm abs]) compared to the active intervention, hyperbaric oxygen (100% oxygen at 1.5 atm abs). It is unknown whether individuals familiar with pressure changes, such as divers and hyperbaric chamber inside attendants, could discern the difference between these pressures and thereby become unblinded to study allocation.

In this study, 80 experienced divers and chamber inside attendants will be enrolled and randomly assigned to one of four possible chamber pressures and one of two breathing gases. After a brief hyperbaric chamber excursion, they will be asked to what chamber pressure they were compressed and what gas they breathed. If participants can accurately report chamber pressure or breathing gas, pressure-familiar individuals should be excluded from blinded clinical trials of hyperbaric oxygen.

Conditions

Traumatic Brain Injury

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: SINGLE_GROUP
• Blinding Strategy: TRIPLE

Study Groups

Sea Level Equivalent 1.2 atm abs (air)

Sham Chamber Session

Sea Level Equivalent 1.2 atm abs (2.6 psig) breathing regular air 20-chamber excursion

Group Type: SHAM_COMPARATOR

Sham Chamber Session

Intervention Type: DRUG

Sham control chamber session: regular air delivered at a chamber pressure of 1.2 atm abs

Sea Level Equivalent 1.5 atm abs (O2)

Hyperbaric Oxygen (1.5 atm abs)

Sea Level Equivalent 1.5 atm abs (6.2 psig) breathing 100% oxygen 20-minute chamber excursion

Group Type: EXPERIMENTAL

Hyperbaric Oxygen (1.5 atm abs)

Intervention Type: DRUG

Hyperbaric oxygen (100% oxygen) delivered at a chamber pressure of 1.5 atm abs.

Altitude Equivalent 1.2 atm abs (air)

Sham Chamber Session

Altitude Equivalent 1.2 atm abs (5.1 psig) breathing regular air 20-minute chamber excursion

Group Type: SHAM_COMPARATOR

Sham Chamber Session

Intervention Type: DRUG

Sham control chamber session: regular air delivered at a chamber pressure of 1.2 atm abs

Altitude Equivalent 1.5 atm abs (O2)

Hyperbaric Oxygen (1.5 atm abs)

Altitude Equivalent 1.5 atm abs (9.6 psig) breathing 100% oxygen 20-minute chamber excursion

Group Type: EXPERIMENTAL

Hyperbaric Oxygen (1.5 atm abs)

Intervention Type: DRUG

Hyperbaric oxygen (100% oxygen) delivered at a chamber pressure of 1.5 atm abs.

Interventions

Hyperbaric Oxygen (1.5 atm abs)

Hyperbaric oxygen (100% oxygen) delivered at a chamber pressure of 1.5 atm abs.

Intervention Type: DRUG

Sham Chamber Session

Sham control chamber session: regular air delivered at a chamber pressure of 1.2 atm abs

Intervention Type: DRUG

Other Intervention Names

HBO2; HBO; HBOT; Sham control; Air pressurization

Eligibility Criteria

Inclusion Criteria

• Adult, age 18 - 65 years
• Completion of medical history questionnaire without concerns identified for exposure to increased pressure
• Familiarity with atmospheric pressure change:
• Experienced and active hyperbaric chamber inside attendant: more than 50 hyperbaric compressions, with more than 4 have been in the last 4 months; or
• Experienced and active SCUBA diver: more than 20 lifetime compressed gas open water (not swimming pool) dives, with more than 10 in the last 12 months
• Able to equalize middle ear pressure easily

Exclusion Criteria

• Pregnancy
• Known risk for barotrauma, as identified on the medical history questionnaire, such as:
• Recent (within 12 months) inner ear or sinus surgery
• Spontaneous pneumothorax
• Pulmonary cysts
• Emphysema
• Bullous lung disease
• Chronic obstructive pulmonary disease needing chronic active therapy
• Inability to tolerate chamber confinement or pressure
• Presence of heart failure
• Presence of any implanted electrical device, except hyperbaric-approved pacemakers
• Presence of middle-ear tympanostomy tubes

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Intermountain Health Care, Inc.

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Lindell K. Weaver, MD

Role: PRINCIPAL_INVESTIGATOR

Intermountain Health Care, Inc.

Locations

Intermountain Medical Center

Murray, Utah, United States

LDS Hospital

Salt Lake City, Utah, United States

Countries

United States

References

Clarke D. Effective patient blinding during hyperbaric trials. Undersea Hyperb Med. 2009 Jan-Feb;36(1):13-7.

Reference Type: BACKGROUND

PMID: 19341123 (View on PubMed)

Jansen T, Mortensen CR, Tvede MF. It is possible to perform a double-blind hyperbaric session: a double-blinded randomized trial performed on healthy volunteers. Undersea Hyperb Med. 2009 Sep-Oct;36(5):347-51.

Reference Type: BACKGROUND

PMID: 20112525 (View on PubMed)

Weaver LK, Hopkins RO, Churchill S, Haberstock D. Double-Blinding is Possible in Hyperbaric Oxygen (HBO2) Randomized Clinical Trials (RCT) Using a Minimal Chamber Pressurization as Control. Undersea Hyperb Med 1997;24(Suppl):36.

Reference Type: BACKGROUND

Weaver LK, Churchill SK, Bell J, Deru K, Snow GL. A blinded trial to investigate whether 'pressure-familiar' individuals can determine chamber pressure. Undersea Hyperb Med. 2012 Jul-Aug;39(4):801-5.

Reference Type: RESULT

PMID: 22908836 (View on PubMed)

Other Identifiers

1023955

Identifier Type: -

Identifier Source: org_study_id