ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

ECHM Recommendations for Safety inmultiplace medical hyperbaric
chambers

Coordination and Correspondence :D. MATHIEU,
Service d'Urgence Respiratoire,de Réanimation Médicale et de Médecine hyperbare Hôpital Calmette- CHRU - 59037 LILLE - FRANCE
Tél : 03.20.44.54.91
Fax : 03.20.44.50.94
E-mail : dmathieu@chru-lille.fr

ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

1 - PRINCIPLES

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1.1 - Scope of work
1.2 - Risk assessment
1.3 - List of reference documents
1.4 - Major points to be considered

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2 - MANAGEMENT AND ORGANIZATION

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2.1 - Responsible persons
2.2 - Supporting documentation* Safety manual* Hyperbaric Equipment Construction Data Book
* Maintenance register* Compression and decompression procedure manual* Day to day logging of personnel pressure exposures
2.3 - Personnel training / medical fitness
2.4 - Relationship with external emergency services
2.5 - Safety posters on site

3 - EQUIPMENT
3.1 - Construction of Hyperbaric Chamber* Pressure vessel* Architecture* Electric devices* Plumbing* Measurements, analysis, recorders* Fire fighting systems* Breathing masks* Lock attendant station
3.2 - Construction of buildings* Patients access* Connection with hospital* Fire precautions* Gas storage, compressors room, distribution plumbing* Equipment authorized for use under pressure
3.3 - Maintenance program* Schedule for maintenance operations* Air quality controls* Maintenance logging* Emergency drills

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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

4 - OPERATIONS
4.1 - Staffing* Number and role of persons* Under pressure patients attending policy
4.2. Patient preparation / control* Information to the patients* Medical preparation* Practical preparation

5 - CONCLUSION

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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

E C H M RECOMMENDATIONS FOR SAFETY IN
MULTIPLACE MEDICAL HYPERBARIC CHAMBERS

1-PRINCIPLES
1.1-Scope of work
The purpose of this document is NOT to produce a new set of rules, standard or regulations
for the safety of H B O. These rules, standards and regulations exist and are available invarious forms and countries. A list of the major international ones is given below forreference.
This document is intended to be guidelines for the manager or any responsible person in an H
B O operation to help him making sure that all necessary safety precautions are taken care ofproperly.

1.2 Risk assessment
To make sure safety precautions are adapted to the situation, a risk assessment is necessary.
This is depending on the type of hyperbaric installation, the patients and the indications, aswell as the number of exposures carried out on a regular basis in the hyperbaric facility.
This document will not provide answers to all questions, it is only guidelines. An adapted
response to eliminate the risks and to reduce the unavoidable ones to an acceptable level mustbe established under the manager control for each particular Hyperbaric Centre.

1.3 List of reference documents
European Directives :CEN Medical devices:
CEN Pressure vessels:
CEN Noise at work :CEN Chemical agents:
CEN Electric devices / explosive atmospheres
CEN Electric devices / electrocution

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93/42/CE
97/23/CE
86/188/CE
98/24/CE
94/9/CE
73/23/CE

dated 14 June 1993
dated 29 May 1997
dated 12 May 1986
dated 07 April 1998
dated 23 March 1994
dated 19 February 1993

ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

Standards :Air quality standard (medical air, breathable air...)
ASME PVHO
1998
NFPA
1998
UHMS (Monoplace 1991 and Multiplace 1994 - HBO Chamber Safety)
ECHM (Training standard) 1997

Other documents : Many independent control organisms have produced rules orcertification
policies for hyperbaric and diving systems which may be used forconformity
assessment of pressure vessels for human occupancy of HBO chambers(Bureau Véritas, Germanishe Lloyd, Lloyds, DNV,...)

1.4 Major points to be considered
Establishing and controlling a safety policy, at work for the attendants as well as in medical
practice for the patients, is one of the duties of the manager of the Hyperbaric Facility. Subdelegation of responsibilities should be clearly set and made known to the personnel.
The equipment used for HBO treatment is susceptible to generate risks both to the personnel
and to the patients, therefore some construction and maintenance standards should be referred
to for the equipment control and for the monitoring of the maintenance and in case of any
modification carried out on that equipment. This topic includes fire protection and fire
extinguishing systems.
Operational procedures need to be specified, posted and logged.

2 - MANAGEMENT AND ORGANIZATION
2.1 Responsible persons
It is the duty of manager of the Hyperbaric Centre to organize safety in the facility and heshould designate in writing who is in charge of:- Equipment, its maintenance and control (from compressed gases supplies to thechambers,
the controls panel, and the exhaust of gases and fire fighting equipment outside andinsidethe chambers),- Running the sessions and monitoring the operation,- Informing the patients, controlling their personal items and objects eventually carried
inside the chamber.

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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

2.2 - Supporting documentation* Safety manual
The safety manual is prepared and signed by the manager of the facility; it should include all
information necessary to carry out the hyperbaric sessions safely, including the description ofduties of the personnel involved. The content of this Safety Manual should be known by all
and specific information should be given to new comers to make sure they are perfectly awareof its content.
* Hyperbaric Equipment Construction Data Book (As built)
A technical document should contain all information concerning the plant, as built drawings,
all certificates with a list and dates of validity for easy check, basic operational procedures,
maintenance program recommended by the manufacturer, and logging of all modifications
carried out on the equipment.
* Maintenance register
Based on the manufacturer recommendations, a register of maintenance should be opened tolog all actions of the maintenance team, in particular formal inspections, re-certifications, andspare parts changes. Near missed or break down should also be entered for further actions.
* Compression and decompression procedure manualAll pressure profiles used in the treatment should be categorized and identified with proper
description. This includes decompression procedures applicable to the exposed personnel on
the occasion of the attendance of the patients.
Any emergency compression (access), decompression (evacuation) or recompression (in caseof DCI symptoms) procedures to be used for the attendants should also be in that document.
* Day to day logging of personnel pressure exposures
A register of exposure should receive information about individual staff exposures, and thesame data should be logged in a personal log-book supplied by the employer to each person
qualified to be exposed to pressure.

2.3 - Personnel training / medical fitness
Any person exposed to pressure should be fit to do so. This is based on occupation medical
fitness to undergo pressurization. A specific assessment is needed on a yearly basis. A
certificate of fitness should be issued, and eventually entered in the personal log-books.
The content of medical examination may be under national rules. If not, it should be definedand agreed with the concerned occupational doctor.
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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

2.4 - Relationship with external emergency services
A joint visit of the plant with the Fire Brigade in charge of the place is highly recommended
and the conclusion should be a jointly defined contingency plan for fire outside the chamberand help in case of fire inside.

2.5 - Safety posters on site
Through out the plant, where specific safety information is needed, proper posters should
remember to the patients and to the personnel the applicable safety rules (Non smoking area,
items not to be taken in the chamber, maximum value for oxygen monitoring and action incase of high alarm signal...)At the lock attendant position, information on panel operation should be clearly displayed(valve function, positions, piping diagrams, emergency items...)3 - EQUIPMENT
3.1 - Construction of Hyperbaric Chamber* Pressure vessel
Specific construction and inspection rules apply to pressure vessels according tovarious national rules. After 2002, European pressure vessels regulation will havebeen harmonized under the Directive : CEN Pressure vessels, 97/23CE, dated 29 May
1997.
* Architecture
Basically the number of chambers in an installation should be such that, in case of
emergency it should be possible to enter the treatment chamber and provide assistanceinside. The minimum is a 2-compartment installation, one chamber being kept at
atmospheric pressure to give access. It is generally considered acceptable to carry out
decompression of personnel in that access chamber provided a procedure is preparedto free that chamber quickly to face the need to enter the main chamber.
Patient access to the treatment chamber is of primary importance for the personnel andall effort should be made to provide mechanical help for handling beds and stretchers
when the entrance doors are not with easy and wide access. Many chambers derived
from diving chambers engineering are very poorly designed in this respect. In addition
this is a serious hazard in case of emergency evacuation.

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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

* Electric devices
Electricity may cause two types of hazards : Electrocution and Fire.
Electrocution prevention
Any electrical medical device in contact with the patients should be protected against
the hazards of electrocution for the patients in accordance with medical rules
applicable to such medical devices.
Any electrical device used in the chamber as tools or equipment should be protectedagainst electrocution as a tool or equipment used in a conductive environment (CENElectric devices, electrocution, 73/23/CE, dated 19 February 1993).
Fire precautions
Fire may be triggered in the chamber either by conductors overheating (short circuit)or by sparks. Due to the high partial pressure of oxygen always present in compressed
air, fire will develop extremely fast if material burning in compressed air is present at
the place of fire trigger
Therefore :All power wires should be selected in the category : M2
All equipment should be built in such a way that no spark may start a fire.
Any equipment not specifically designed for use in compressed air should bevalidated by a competent person who will assess the risk of bursting a fire during
normal use and in case of breakdown (fail safe).
A simple means to prevent dangerous, sparks is to select electrical equipment withCE marks showing it is acceptable for use in flammable or explosive atmosphere(CEN Electric devices, explosive atmospheres, 94/9/CE, dated 23 March 1994,* Plumbing
Regular piping should be in agreement with pressure vessels systems rules.
Oxygen and gases with high oxygen concentration (FO2 > 0.25) circuits, require
special precautions (reduce pressure as much as practicable in all distribution lines, allequipment must be oxygen compatible and internally cleaned by a competent person
on installation). No ball valve should be used to operate oxygen circuits. All gas
storage area should be properly ventilated or equipped with a leakage alarm (highoxygen content).
Connecting oxygen cylinders to the circuit should be made only by qualified
personnel.

5ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

* Measurements, analysis, recorders ...
Calibration of meters is part of the maintenance program. It should be done at regularintervals and logged into the maintenance register.
Pressure profiles and oxygen content of the atmosphere should be recorded* Fire fighting systems
Internal fire fighting system includes : A manual extinguishing system operable by theattendant, a sprinkler type water deluge triggered independently from inside oroutside. Override valves (inside and outside) should be available to prevent flooding
when fire is eventually under control.
It is part of fire prevention to be able to decompress quickly the chamber forevacuation and at the same to cool efficiently the burning material and reduce
immediately the partial pressure of oxygen closer to 0.2 bar. A fast decompression
valve operable from outside at the attendant position, eventually sealed with a safety
breakable thread, is a strong recommendation.
* Breathing masks
In case of fire it is extremely important that any extra oxygen input in the atmosphereshould be stopped, and that breathing masks be available for all. Shifting HBO masks
to air will cover the need for the patients; extra masks should be available, one foreach attendant eventually present in the chamber.
Very little can be done to protect hoses delivering gases to the masks, they should bebuilt in heat and fire resistant material, the deluge system is intended to protect them
until evacuation can be carried out.
* Lock attendant station
A special care should be given by the manufacturer of the system to make the controlof the chambers easy and fool proof. Proper markings are needed showing gas circuits
and functions of valves as well as their position. When video screen are used, theirlocation and brightness should be controlled. Communication system should have aback-up arrangement, and the quality of microphones and speakers in the chambers
should be of good quality, a permanent listening capability for the lock attendant isneeded. A telephone line in connection with the telephone control panel of thebuilding should be available at the position of the lock attendant
Noise level due to decompression of gases should be removed from the place byproper piping and silencers.

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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

3.2 - Construction of buildings* Patients accessIn addition to the access to the chamber some care should be given in the room
available for patient preparation, inspection and handling around the installation inparticular when intensive care patients are concerned.
* Connection with hospital
Many of the indications of HBO are for intensive care patients, who require special
equipment and transport from the hospital, a close connection with the hospital is amust for Hyperbaric Centres accepting intensive care indications. This includes
laboratories and medical analysis capabilities.
* Fire precautions
The hazard of fire in the Ilyperbaric, facility are related to gas storage, oxygen circuits,pressure vessels and the fact that for some indications decompression of patients forevacuation may be fatal to the patient (arterial embolism, DCI, some CO poisoning
cases ...). And it also may be dangerous for the attendant involved in such cases.
A contingency plan should be prepared with the fire brigade to take into account thosespecific hazards and organize fire fighting procedure accordingly.
All markings in relation with fire fighting and evacuation must be displayed* Gas storage, compressors room, distribution plumbing...
It is of primary importance that, in all situations, pressure could be maintained in thechamber and that ventilation should not be interrupted for more than a few minutes.
The gas supply system should be so arranged that in case of failure (compressor,
electricity, cooling water, piping breaks ...) a back up system become operational atonce to match the gas requirements for the treatment and the possible required
decompression of personnel. This can be achieved via gas storage, emergency
compressors, emergency electric supply... A document should demonstrate the risk
assessment, which leads to the choice of an adapted solution. The corresponding
emergency procedure should be in writing and should be part of the training of thepersonnel in charge.
* Equipment authorized for use under pressure
The equipment permanently used in the chamber and designated for use underpressure should be devoted to that activity and be clearly identified. It should havebeen evaluated for suitability of the purpose either by the initial manufacturer of thechamber or jointly by the user and the manufacturer of the equipment.

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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

A list of those equipments should be part of the safety manual. Example: hospitalwheel chairs should be greased with non burning grease, private wheel chairs have tobe left outside, ...
Any new item to be entered into the chamber should be controlled by a competentperson who will sign an authorization to use under pressure, eventually in association
with special recommendations or safety rules when applicable and after questioning
the manufacturer.

3.3 - Maintenance Program* Schedule for maintenance operations
In the instruction manual provided by the manufacturer of the installation, there should
be proper guidelines for the maintenance schedule. The manager of the installation
will formalize the maintenance program in the safety manual.
In particular only products and spare parts recommended by the manufacturer should
be used (oxygen compatible lubricants for example).
* Air quality controls.
The frequency of air quality controls is depending of the type of compressors used, thetype of filtering units and the activity of the centre. This should be defined inagreement with the guidelines given by the manufacturer(s) of the gas production plantand incorporated into in the safety manual.
* Maintenance logging
All maintenance operations carried out by technicians should be logged in themaintenance register and signed by the technician in charge.
Entries should be left open for the personnel to report on day-to-day breakdowns andremedial actions taken.
* Emergency drills
The manager of the installation should recommend safety drills, mostly oriented
towards fire prevention and fire fighting, all personnel should participate to thosesafety drills, which should also be logged in the operation log-book.

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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

4 -OPERATIONS
4.1 - Staffing* Number and role of persons
During any treatment the functions involved are :Supervision of the treatment (medical aspect and safety of operations),
Operation of the chambers,
Attendance of patients under pressure,
Emergency assistance under pressure if needed
Depending on the type of centre, the number of simultaneous use of pressure chamber
the minimum team stalling is variable. There should be a minimum of 3 qualified
persons outside (Supervision, lock attendant and emergency help).
Any staff member accepted for compression should be medically fit to undergopressurization.
* Under pressure patients attending policy
It is presently a common practice in several hyperbaric units not to attend walk-in
patients for the whole session, the attendant being locked out after compression oreven not being compressed at all when patients have experience of the exposure
The policy on patient attending under pressure should also be clearly defined in thesafety manual. Instructions to un-attended patients should be sufficient for them toface minor problems under pressure and to control properly oxygen mask leakage(both ways).

4.2 - Patient preparation / control* Information to the patients
The content and the procedure of information to the patients should be clearly
established, eventually with a specific leaflet or document to be given to the patients,on the occasion of exposures. Who is in charge of this information and copies of the
documents are to be included in the safety manual.
* Medical preparation
Before entering the chamber, all patients should be controlled to assess their medical
situation, in particular when they are connected to medical devices or when they were
dressings on wounds ...
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ECHM Recommendations for Safety in Multiplace Medical Hyperbaric Chambers 1998

* Practical preparation
Policy concerning patients clothing, bedding equipment, inspection of personal items
is needed, A recommendation should be that patients keep a minimum of personal
clothes and receive at least a blouse covering the remaining clothes. That blouse being
made out of low flammability material (cotton). Consequently a personal items storage
look should be made available for each patient.

5-CONCLUSION
Basically there are few construction problems left when the manufacturer of the HBO facility
is safety conscious and the buyer ready to invest in a safe system. Most of the safety
problems in HBO are related to the procedures used and the precautions enforced during the
day-to-day work.
These precautions are directly under the control of the personnel. The personnel should bewell aware of the centre safety policy; he (she) should have received the initial training, acopy of the safety manual and be given a clear definition of his (her) responsibilities during
the sessions.
The management, after establishing that policy in a safety manual, should also make sure it isproperly applied. This needs personal involvement and frequent controls.

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