Initial Hazard Analysis REVISION 4 (Final): Revised 4/17/2006 BIOE 1160/1161: Senior Design Calano, Kumar, McNeal, Odle The device to be developed is a neck brace specifically for patients suffering from neuromuscular degenerative diseases, namely Amyotrophic Lateral Sclerosis (ALS). There are a few potential hazards that may arise while a patient uses this device. These hazards include suffocation, skin irritation, overheating, difficulty swallowing, and neck soreness and pain. Once these hazards were identified, the cause and severity of each hazard was identified as well and each hazard was assigned an initial hazard score. 1. Suffocation: After meeting with representatives from the Pittsburgh ALS Association, it was learned that if the neck brace collar is too soft, the patient’s head can sink down into brace. The brace may then cover the patient’s mouth and possibly also their nose causing difficult breathing. Sometimes patients were found slumped over and their brace had cut off their air circulation, causing suffocation. If left like this for too long, the patient can die. Therefore, it was determined that suffocation be deemed a highly severe hazard. Suffocation can also be a concern for larger patients because the neck brace may not fit them properly. 2. Skin Irritation: Once ALS patients have progressed into the stage of the disease where they can no longer hold their neck up on their own, they must wear a neck brace. Many patients wear their brace for many hours during the day and sometimes even when they are in the shower or sleeping. During this extended period of wear, the neck brace has constant contact with their skin and may cause skin irritation. Skin breakdown was deemed a medium severity risk since it would not cause life threatening harm to the patient. Skin breakdown is painful, but inevitable since the brace is worn frequently. Patients do have the option of taking the brace off, but the comfort they gain by decreasing skin irritation is balanced by a decrease in neck support. 3. Overheating: ALS patients have limited options when it comes to choosing a neck brace. There are two main neck brace types: the “closed” neck brace with material contacting the neck around the entire circumference, and a brace with an “open” neck area which may provide slightly less support but more air contact with the skin. Patients are more likely to choose the brace with the exposed neck because the soft collared brace causes them to overheat, since there is no ventilation. Although overheating is a concern, this risk was considered low severity because the harm to the individual is not as severe as the other hazard types. 4. Difficulty swallowing: If an ALS patient’s chin is too high or there is a lot of pressure on the neck area, the patient will have difficulty swallowing. Also, the most current braces are not customized for the varying neck girth of each patient causing larger patients have problems with pressure on their neck area. Neck braces are also not usually customized for height. Shorter patients have problems with their chin being too high. This was given a medium risk because the patients can take their brace off to eat or readjust the positioning of the brace around their chin for a short period of time while eating. 5. Neck soreness/pain: Patients who suffer from ALS already encounter muscle soreness and pain. In addition, they can suffer from additional neck soreness and pain if the brace is improperly positioned on their neck, especially if height and weight are issues for the patient. Since this can be remedied by readjusting the brace, this hazard was given a low severity. After identifying the hazards and the severity, the probability of each hazard occurring based on its cause was considered as well as the level of risk involved. Risks were measured on a scale of 1-4, with 1 being an intolerable risk and 4 being a negligible risk. A risk ranking of 2 is for any hazard that was undesirable. An undesirable risk was defined as tolerable only if reduction is impractical or if the costs were gross. A risk ranking of 3 was considered tolerable. A risk was defined as tolerable if the cost (both monetary and cost of decreased functionality) of the risk reduction would exceed the improvement to be gained. Probability of Harm Due to Cause: The probability of the soft collared brace causing suffocation was low, since it does not occur that often. This usually occurs after a long time of usage, and not when the patient initially puts the brace on. The probability of improper fitting causing suffocation was low because it can be remedied by readjusting the brace on the patient. However, both the improper fitting and the collar being too soft were ranked 1 because they both would be intolerable to the patient if either were to occur. Skin irritation caused the rubbing of the collar on the skin has a medium probability of causing harm. This risk was ranked a 3 because it only causes slight discomfort and will only occur after long periods of use. Overheating has a low probability of causing harm since the neck brace has an open design. It is a negligible risk because the brace can be taken off if the person gets too hot. Also, overheating is less of a concern outside of warm summer months. Difficulty swallowing due to the patient’s chin being too high has a low probability of causing harm since the brace can be readjusted or taken off for the person to eat. It has a low probability of occurring as well. It was given a rank of 2 because it would be uncomfortable for the patient. Difficulty swallowing due to pressure on the neck area has a low probability of causing harm because it is likely to happen in the open design. It was ranked with a risk factor of 2 because the resulting discomfort would most likely cause the patient to remove the neck brace and defeat its functional purpose. Neck soreness and pain due to improper positioning has a medium probability of causing harm. This is because it is likely to happen if the brace is not put on correctly. It was given a risk ranking of 3 because it has low severity, but a medium probability of occurring. Design Controls To improve the current neck brace designs, the methods of control for each hazard were assessed. Control measures were adopted for each hazard based on the methods of control. Suffocation due to the collar being too soft is a design control for which the control measure adopted was to choose a firm yet comfortable material. Suffocation due to improper fitting is a process problem since the patient is the one who puts the brace on improperly. The control measure adopted was to design the new brace to be girth adjustable to enable a better fit. Skin irritation due to the collar rubbing against the skin is a design issue. The material the brace is made out of may cause or increase the irritation. The control measure would be to make the brace out of a hypoallergenic or non abrasive material to prevent skin breakdown. Overheating due to a lack of ventilation is a design issue because the current closed designed braces completely covers the neck. The control measure would be to use a breathable material to allow more ventilation or create a neck brace with an open design allowing the neck area to be exposed to air. Difficulty swallowing due to the chin being too high is both a design and process issue. It is a design issue because at times the size of the neck brace is not appropriate and it is not possible to position the patient’s chin at a comfortable height. It becomes a process issue when the patient does not position his or her chin correctly on an appropriate brace. The control measure that would remedy both methods of control would be to make the brace height adjustable or to offer an array of sizes. Difficulty swallowing due to pressure on the neck area is a design issue because the brace itself would be putting extra pressure on the patient if he or she is overweight. The control measure would be to design an open brace or make the brace girth adjustable. If the brace is open, the weight of the brace is decreased because there is less material, so the brace places less pressure on the patient’s neck. If the brace is girth adjustable, larger patients will have a benefit from a fit that better supports their weight. Neck soreness or pain due to improper positioning is a process issue since it is the patient who puts the brace on wrong, causing themselves more pain. The control measure would be to make the brace girth adjustable and available in different heights so the best fit is ensured. New probabilities/risk New probabilities and risk rankings were assessed for each control measure. The probability of suffocation due to the collar being made from a non collapsible material is very low because the brace is less likely to cause the patient’s neck to sink into the brace. It was then given a risk ranking of 4 because suffocation would then be a negligible concern. The probability of suffocation occurring in an open design brace is also low. This is because there is no material to cover the patient’s mouth and/or nose even if the head should happen to fall down into the collar. The ranking of 4 stands. Skin irritation due to the brace being made from a non abrasive or a hypoallergenic material is low. This is because it is likely that some skin irritation will occur despite constant contact of the brace with the patient’s skin. Therefore, it was given a risk ranking of 3. The probability of overheating occurring if the brace has either an open design and/or is made from a more breathable material is low. It was given a risk ranking of 4 because overheating does not occur often, and it would occur even less if the control measures were taken into account. Difficulty swallowing is less likely to occur with a variety of heights available to the user. Custom height adjustability can also be incorporated by custom making the chin cup. Swallowing would become less of an issue because the chin would be at the right height for all patients. Since the probability of this occurring is very low, it was ranked with a risk factor of 4. The probability of having difficulty swallowing with a brace that has an open design or is girth adjustable is very low. This is because less pressure would be placed on the neck. It was given a risk ranking of 4 since it was less likely to occur. Neck soreness and pain with girth adjustable brace that has a variety of heights and custom height adjustability available is very unlikely to occur. Both control measures ensure the best fit for each patient because the fit could be more customized. Therefore, it was given a risk ranking of 4.