Endotracheal Tube Adaptor for Aerosolized Medication AbstractThe goal of this project is to develop an endotracheal tube adaptor that can be used to consistently deliver aerosolized medication directly to an anesthetized patient during surgery by the anesthesiologists at the UW-Hospital. Aerosolized medications such as Albuterol and Ipratropium, are routinely used to control the symptoms associated with asthma attacks and bronchospastic disease. While a patient is anesthetized they may require this aerosolized medication during surgery should they have a sudden asthma attack. The adaptor will act as an interface between the anesthesia circuit and the patient and will be available to deliver either of these types of medication should the need arise. The device should not impede the anesthesia circuit and should solely act as a port to deliver medication should it be needed during surgery. Our client would prefer an adaptor that either works with the patients plastic canister housing dispenser, directly with the new metered dose inhaler (MDI; Albuterol or Ipratropium), or as an addition to his current adaptor. This device should also be a long lasting and able to withstand multiple cleanings with MetriCide disinfecting solution.Problem StatementFor nearly 30 years our client, along with other anesthesiologists at the UW-hospital, has used an adaptor called the Bronchodilator Tee which is 1Evan JoyceRyan ChildsTimothy BarryOzair Chaudhry3/11/2009manufactured by Boehringer labs. This adaptor allowed them to directly deliver highly concentrated aerosolized medication (Albuterol or Ipratropium) to their intubated, anesthetized patient through the patient’s endotracheal tube. However, a new change to the aerosolized medication canisters used at the UW-hospital has rendered the Bronchodilator Tee ineffective at delivering medication. The new canisters have been fitted with a non-removable actuation counter to aide in patient awareness as to how much medication is left in their personal MDI. No other adaptors on the market have addressed this new MDI canister design so there is no way for our client to calm an asthmatic patient during surgery. This presents a large safety issue to all patients with a history of asthma attacks. Our goal throughout the semester is to design and fabricate a new adaptor that will allow a quick and effective means of delivering medication from this new MDI canister design. BackgroundOur client is Dr. Mark Schroeder, an anesthesiologist at the UW Hospital and an Associate Professor of Anesthesiology at UW-Madison. Our client sees dozens of patients monthly. Of these patients, only about 2-3 require the administration of nebulized medication during surgery due to complications related to asthma or bronchospastic disease. These patients will be hooked up to an anesthesia circuit similar to the one shown above. The gas will flow 2Figure 1: Anesthesia circuitcounterclockwise through the system, and the patient will inhale and exhale through the Y-piece in the figure. In order to allow medication to be introduced to the system, an adaptor must be incorporated into the circuit. One port of the adaptor will connect to the Y-piece, with the other connected directly to the endotracheal tube which runs down the patients throat. This provides an easy and direct way for the nebulized medication to travel to the patient's lungs.All endotracheal tubes have a standard ISO connector with an outer diameter of 15 mm. This connector will fit into the inner diameter of our adaptor. Additionally, the tubing which runs from the Y-piece into the adaptor has an outer diameter of 13 mm. Thus, the inner diameter of the side port of our adaptor will be 13 mm. Our adaptor must be compatible with these dimensons.Problem MotivationPatients on mechanical ventilators sometimes need aerosolized medication delivered to them while in an operation. They are connected to the anesthesia circuit though the endotracheal tube which cannot be taken out from their mouths. This problem can be solved by annexing an adaptor to the circuit, although the adaptor must maintain a closed circuit to ensure no net gas flow leakages. Anesthesiologists at the U.W Hospital, previously mentioned, use an adaptor with such features, called the Bronchodilator Tee. This adaptor has 3 ports of which one connects to the anesthesia circuit, one to the endotracheal tube and one where the MDI canister fits in to deliver the 3Figure 2: Bronchodilator Teemedication. This adaptor works really well with the anesthesia circuit for several reasons. Firstly, it delivers the medication effectively without comprising the efficiency of the circuit. It doesn’t impede the pre-determined minimum gas flow rate of 4-5L/min, so that there are no abnormalities in the anesthesia circuit system. Moreover it maintains the closed circuit since the port where the MDI canister fits in has an attachable cap to it, which can be closed after the medication has been delivered. Hence, the Bronchodilator Tee prevents the dilution of the anesthesia mixture, which is extremely advantageous as then the patient is much less likely to wake up during an operation.Why a new adaptor is neededRecently, the FDA banned the use of MDI canisters that used chlorofluorocarbon (CFC) gases as propellants, since they are damaging to the environment. These types of canisters are aimed to be completely removed from the market by 2010. Medical companies now have been designing a new canister with an eco-friendly propellant. GlaxoSmithKline is a relatively known company for producing such a canister. The propellant 4Figure 3: New MDI canisterthey, as well as other companies now, use is a hydrofluoroalkane (HFA) and has been deemed environmentally safe. However, not only have the propellants of the new canisters been changed, but also its geometry. The canister now has an actuation counter built on the cap of the canister for the purpose of letting the patient know how many doses they have
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