Mechanical ventilators are medical devices used to provide respiratory support in cases where patients have severe respiratory problems. These devices have many modes and parameters. The required respiratory parameters are set and the device is connected to the patient. This connection may be via an endotracheal tube, tracheostomy cannula, or face-worn mask. If the mechanical ventilator performs an application outside the set parameters, the life of the patient may be endangered. For this reason, the devices are produced to work precisely and without errors. Thus, respiratory support can be provided without any deviation from the set values. The air sensors used in the devices are also very sensitive and of high quality. Although this provides a great advantage in terms of health, it can sometimes cause other problems. There may be some problems, especially in household mechanical ventilators. For example, users of the Puritan Bennett 560 mechanical ventilator are most likely to have encountered the "e sensitivity alarm". This alarm does not represent a major risk to the patient's health. Although the device gives an alarm, the breathing cycle continues normally. However, it is necessary to solve the problems that cause the alarm and silence the sound of the alarm, as it may disturb the patient and the attendants.
Household mechanical ventilators consist of parts such as casing, battery, electronic card, sensor, valve and turbine engine. The device is managed by the electronic card. The electronic card gives the necessary commands to the turbine engine to produce compressed air. The pressure and amount of air to be applied to the patient are controlled by sensors and valves. The values of the air going to the patient are measured and displayed on the screen of the device. Some mechanical ventilators can measure the volume of air leaving the patient along with the volume of air going into the patient. Since the measurements of the breath coming out of the patient are affected by external factors, the devices tend to give more alarms during the exhalation phase. The E sensitivity alarm also appears in this process. Usually, it is a problem with the breathing circuit (hose). The device may frequently give an e-sensitivity alarm when the breathing tubes are irregular and tangled. To prevent this, it must be ensured that the breathing circuit stops properly. The device gives this alarm for about 10-15 minutes and stops it. However, if the alarm lasts longer than 15 minutes, circuit calibration should be performed. It is also observed that the alarm is stopped when ventilation is stopped and restarted.
After a while after turning the device off and on, the sensitivity alarm may appear again. This may not provide a definitive solution. The problem should be solved in the long term by performing circuit calibration. Circuit calibration can be done from the device's menu. It takes approximately 3-4 minutes. Since it is necessary to separate the device from the patient during this process, manual respiratory support should be provided with a spare device or a resuscitator (ambu) set. Circuit calibration has a special technique. However, it can be completed by applying the right technique. Therefore, how it is done should be learned from the device specialists.
The E sensitivity alarm can also occur due to air leakage around the tracheostomy cannula. This problem may occur in the use of a cuffless tracheostomy cannula or in cases where the cuff is deflated if a cuffed tracheostomy cannula is used. If the problem is caused by the tracheostomy cannula, there are several solutions. If the patient is using a cuffless tracheostomy cannula, switching to either a larger size cannula or a cuffed, ie ballooned tracheostomy cannula may solve the air leak problem. If a cuffed tracheostomy cannula is used, the cuff must be inflated. If a cannula change is required, this should be done with the approval of the patient's physician.
The mentioned techniques may not provide a definitive solution to the problem, and the device may continue to give the same alarm after a while, albeit with a low probability. Since it does not pose a great risk to health, the solution of the problem can be delayed, but the alarm sound of the device continues to disturb the patient and his companions. Apart from the temporary solution techniques, it is also possible to completely fix the problem. In this regard, it is necessary to seek help from the patient's physician. The physician can reach the definitive solution by changing the expiratory sensitivity setting of the device to suit the patient. Thus, the device can be set to work in sync with the patient. The device's compatibility with the patient both improves blood gas values and provides a more comfortable care process. In addition, as the external effects during the exhalation phase of the patient are defined to the device, the "e-sensitivity alarm" is also eliminated. The expiratory sensitivity setting represents a very important parameter to synchronize the device with the patient.