THE BURMAN RISK SCORING SYSTEM 

Quantifying risk magnitude through a practical scoring approach

When considering a material, dressing, disinfectant, piece of equipment, or other product for use in a hyperbaric chamber, a consistent process should be followed to ensure that any identified, real risks can be effectively mitigated.

As a general rule, very few products are manufactured specifically for hyperbaric use, or evaluated and declared effective and/or safe by manufacturers. However, and in equal measure, many typical healthcare products do not present any significant risk of endangering patients, staff, or facilities.

Medical products require FDA approval prior to marketing and sale, but even with this approval, this does not apply in many cases to cover a hyperbaric medicine application. In order to meet the FDA requirements for off-label use, the medical director is required to make a decision both in the best interests of the patient and with due regard to safety.[3]

The exposure of patients, staff, and equipment to the hyperbaric oxygen environment will always present some degree of risk, which should be evaluated and mitigated as much as is practically and realistically achievable.

A risk assessment process based on identified hyperbaric facility hazards should allow each item to be properly evaluated and an appropriate risk level determined, enabling the risk management team and the medical director to make an appropriate decision.

Types of Risks

Three categories of risk need to be considered: fire, mechanical and physiological. Items under consideration should be evaluated in order to determine whether any or all of these categories apply, and if so, what the magnitude of the risk would be.

Definitions

• Risk: a risk can be defined as the probability of an exposure to a hazard leading to negative consequences. This in turn allows each of the above three identified areas of concern to be scored, using a Likert Scale (i.e. a type of rating scale) for probability, frequency of exposure and severity of potential consequences.
• Fire hazards: fire has been proven to be the greatest of the risks encountered in hyperbaric chambers through the review of more than 95 years of experience in this field.[1] Items introduced into the hyperbaric environment should be considered in terms of a potential source of fuel, an ignition source, and the exposure to oxygen to promote and accelerate combustion.
• Mechanical hazards include anything that leads to [4]:
• • Impaired access: any restriction to movement inside the chamber due to placement of medical devices, cables or hoses may result in a trip injury or the equipment falling and injuring an occupant.
    
  • Reduced visual access inside the chamber: reduction or restriction of visual access of chamber operators reduces their effectiveness as safety monitors (e.g. an external fixator that scratches the chamber acrylic window).
  • Collapse or rupture during changes in pressures: for instance, sealed or semi-sealed containers that are not adequately vented left inside the chamber will either collapse under pressure (possibly resulting in adiabatic heating of the contents and thus imposing a fire or explosion risk); or explode on resurfacing if the gas trapped within the container cannot escape during the ascent.
  • Malfunction, disruption or inoperativeness of many standard items when placed in service under hyperbaric conditions: includes the implosion of lamps and vacuum tubes (e.g., cathode ray tubes in medical monitors), failure of pressure-touch switches, overloading of fans due to a higher gas density, inaccurate operation of flowmeters, pressure gauges and regulators.
• Physiological hazards [4]: Physiological hazards for the purpose of the Risk Assessment Tool include those arising as a result of mechanical, electrical or other safety malfunctions. For instance:
• • General hazards: these include electric shock or overheated materials leading to acute burns, CO poisoning, intoxication by products generated during the combustion of materials (e.g., cyanide and chlorine).
  • Uncomfortably high noise for the patient: may occur during operation of medical equipment, such as operation of a fan or a mechanical ventilator.
• Probability of an accident: the likelihood that an incident or accident such as combustion due to fire/explosion, mechanical failure of the chamber, or undesired physiological event will happen as a result of exposure to the hazard.
• Frequency of exposure: how often will the facility, occupant or staff member be exposed to the hazard, if no mitigation actions are taken.
• Severity of potential consequences: severity of the outcome, should an accident occur.

The Burman Risk Assessment Scoring Process

• 1. Use Tables 1-3 to assign scores to the items below.[4] When assigning scores, make a realistic assessment of the actual risk of each of three types of events (i.e. fire and explosion, mechanical hazards, physiological and medical hazards):
• • a) The probability of an accident (i.e., the probability/ likelihood of occurrence) (Table 1),
  • b) The frequency of exposure to the hazard (Table 2), and
  • c) The severity of the outcome (i.e., potential negative consequences) should an accident occur (Table 3)
  • • When determining severity of the outcome, consider a realistic worst-case scenario 
      
• 2. Multiply the score assigned to the probability of an accident, the frequency of exposure to the hazard, and the severity (Risk Score = probability x exposure x consequence):
• • For instance: if the probability of fire and explosion is definite (score=5), the frequency of exposure to the hazard is continuous during an entire shift (score=5), and the severity of the outcome should fire and explosion happen is catastrophic (score=5), then the risk score for fire and explosion is 125 (5x 5 x 5 =125)
• 3. Compare the calculated risk score (e.g. 125) to the ranges in Table 4 and identify the risk level 
• 4. Where exposure to the hazard leads to more than one type of risk, each risk should be assessed separately (that is, the risk score should be calculated as probability x exposure x severity) and the highest score used to determine if the item can or cannot go into the chamber. 
• • For example, if there is risk of fire and explosion and also risk of mechanical hazard, calculate the risk score for fire and explosion and also calculate the risk score for mechanical hazard using the formula Risk Score = probability x exposure x consequence.

Table 1. Burman Scoring System Risk Assessment Process: Scoring the Probability/Likelihood Of An Event

Table 4. Magnitude Of The Risk: Consolidated Risk Score

Examples 

The following examples illustrate the process when applied to items typically seen in a hyperbaric environment.

Example 1: Blankets for use in an oxygen-filled monoplace chamber:

The potential hazards are fire and the accumulation of lint blocking the exhaust system. There are no likely physiological risks.

The initial risk assessment:

1. Risk: Fire and explosion

   • Identifying risks:
     • Fuel: the NFPA 99 allows a suitable blend of cotton and polyester. The most likely fuel would thus be lint.
     • Oxygen: continuous exposure
     • Ignition source: blanket materials with the exception of those prohibited by NFPA 99 (e.g. silk or wool) require a significant amount of heat to initiate combustion.
   • Assigning scores:
     • Probability of fire: 1 (combustion unlikely)
     • Exposure: 4 (less than twice a day)
     • Consequence: 5 (potentially catastrophic based on history)
   • Quantifying the risk level:
     • Risk score: 1 x 4 x 5 = 20
     • According to Table 4, a score of 20 represents a medium fire risk (risk level 2), requiring the usual attention and discipline in operation

2. Risk: Mechanical:

   • Identifying risks:
     • Lint production is based on the actual material to be used.
   • Assigning scores:
     • Probability of sufficient accumulation: 1 (failure unlikely)
     • Exposure: 4 (less than twice a day)
     • Consequence: 1 (slowed ascent rate due to outlet filter blockage, increase ascent rate where the exhaust regulator has lint on the seat).
   • Quantifying the risk level:
     • Risk score: 1 x 4 x 1 = 4
     • According to Table 4, a score of 4 represents a very low mechanical risk (risk level 1), easily mitigated through regular inspection and cleaning.

Impression

With due attention to keeping out any known ignition sources – such as any substance that could have an exothermic reaction and resulting in temperatures higher than 140°F, selecting as blanket material that has restricted lint production and potential for static electricity generation, and through regular cleaning of the chamber, this risk can be rendered as ‘Acceptable’ - certainly no greater than typical scrubs used in a facility – and especially where mandatory grounding of patients is required.

Example 2: Wound-care product that cannot be removed prior to hyperbaric oxygen treatment as per physician orders

The potential hazards are fire and a potential reaction to the product through exposure to an elevated partial pressure of oxygen.

THE INITIAL RISK ASSESSMENT:

1. Risk: Fire and explosion

• Identifying risks:
• • Fuel – The product Safety Data Sheet (SDS) should be consulted to determine whether any volatile vapors can be released at expected chamber temperatures and elevated partial pressure of oxygen (this information is not always easy to obtain – the manufacturer may need to be consulted).
  • Ignition source – in the event of any potentially flammable materials, the required heat to initiate a fire is relatively low.
• Assigning scores: 
• • Probability of fire: 3 (combustion possible if any flammable vapors can be released)
  • Exposure: 4 (less than twice a day)
  • Consequence: 5 (potentially catastrophic)
• Quantifying the risk level
• • Risk level 3 x 4 x 5 = 60
  • According to Table 4, a score of 60 represents high risk - risk mitigation needed prior to use. Ensuring no flammable vapors can be released, grounding the patient and ensuring prohibited items are excluded from the chamber, would reduce a probability of fire to a 1 (new risk score 1 x 4 x 5 = 20). In addition, a damp towel could be placed over the dressing area to further protect against any possible ignition.

2. Risk: Physiological

• Identifying risks:
• • Amended uptake of medication/dressing product.
• Quantifying the risk level:
• • No possibility for any human reaction would yield a risk score of 1 x 4 x 0 = 0
  • Potential reaction of medication with oxygen (not as yet been reported): 3 x 4 x 3 = 36
  • A score of 36 represents a medium risk – treatment not advised if this specific product is used.

Impression

Risk assessments and mitigation steps taken should be undertaken in writing and presented to the medical director for endorsement.

CONCLUSION

The NFPA 99 Chapter 14 provides an algorithmic process that should be followed to determine risk of patient care items that may be introduced into the hyperbaric environment.[2] Despite the NFPA's requirement that all facilities have their own “use list” and a “do not use list” of items that have been evaluated for hyperbaric use" [2], several challenges prevent compliance. Frequent obstacles include lack of understanding of the purpose of the NFPA risk assessment algorithm, and the scarcity of information even upon completion of the risk assessment process to determine whether an item may or may not be allowed into the chamber. The Burman risk scoring system provides a practical scoring approach to help safety officers and medical directors determine whether patient care items may be allowed into the chamber. For an updated decision tree, scoring system, and standardized evaluation process to identify and mitigate potential safety go/no go risks in the hyperbaric chamber environment, see topic "How to Assess HBOT Prohibited Items: The Go-No/Go Risk Assessment Tool and The Burman Scoring System".

CATEGORY A CONTINUING EDUCATION CREDIT

This topic has been reviewed and approved by the National Board of Diving and Hyperbaric Medical Technology (NBDHMT) for one (1) Category A Credit. 'Meeting the Category A requirement related directly to any combination of hyperbaric operations, related technical aspects and chamber safety.'

To claim the credit: 

• 1. Read the topic
• 2. Answer the examination and course critique questions. 
• Take the quiz via SurveyMonkey 
• 3. Receive the certificate by e-mail. A passing score of 70% is required (please allow up to 8 business days for processing)

For more information on Category A continuing education credits see blog post " Hyperbaric Certification and Continuing Education for Technicians & Nurses".