A cough assist machine, formally known as a Mechanical Insufflation-Exsufflation (MIE) device, is a non-invasive medical tool designed to help patients clear secretions from their lungs. This device simulates a natural, forceful cough by rapidly changing the pressure within the airways. It first delivers a positive pressure to inflate the lungs, then quickly switches to a negative pressure to generate a high expiratory flow rate. This mechanism is particularly helpful for individuals whose respiratory muscle weakness prevents them from generating an effective cough to expel mucus. While this guide provides general usage information, it does not replace the specific treatment plan and pressure settings provided by a healthcare provider or equipment supplier.
Preparing the Machine and Patient
Before initiating the therapy, ensure all necessary supplies are gathered, including the MIE device, the circuit tubing, a bacterial or air filter, and the patient interface, such as a face mask or mouthpiece. The patient should be positioned comfortably, ideally sitting upright or semi-reclined at an angle of at least 45 degrees, with adequate head support. This upright posture assists gravity in mobilizing secretions and maximizes the mechanical effectiveness of the pressure changes.
The equipment circuit must be connected in the correct sequence to ensure safety and functionality. A bacterial filter is attached directly to the air outlet port on the machine, and the circuit tubing then connects to the filter. The patient interface, whether a mask or mouthpiece, attaches to the end of the tubing. Never operate the device unless a bacterial filter is properly attached to the patient circuit, as this protects the airways from contaminants.
Once the circuit is complete, the machine should be plugged into an electrical outlet, and the power turned on. Before securing the mask to the patient, confirm the pressure settings match the prescribed values from the physician or respiratory therapist. These settings include the positive insufflation pressure and the negative exsufflation pressure, which are typically measured in centimeters of water (cm H2O). Confirming the settings prevents the delivery of incorrect or ineffective pressure.
Performing the Full Treatment Cycle
The treatment begins after placing the mask securely over the patient’s nose and mouth, ensuring a proper seal to prevent air leaks. Initiating the therapy is done by pressing the start button or switching from standby mode. The first phase, insufflation, involves the machine delivering a positive pressure breath to inflate the lungs, similar to a deep, supported inhalation. During this phase, the patient should be encouraged to relax and breathe in as deeply as possible with the machine.
Following the deep breath, a brief pause or hold time keeps the lungs fully inflated. This pause is immediately followed by the exsufflation phase, where the machine rapidly switches to a negative pressure. This sudden pressure reversal generates a forceful outward flow of air, effectively mimicking the high expiratory flow rate of a natural cough. The patient will feel a gentle, yet strong, sucking sensation that helps propel secretions up the airways.
A full treatment set typically consists of repeating the entire cycle—insufflation, pause, and exsufflation—about three to five times consecutively. After each set of cycles, the patient should be disconnected from the machine interface and allowed a short rest period, usually around 30 seconds, to prevent hyperventilation. The process is repeated three to five times, or as directed by the treatment plan, until secretions are cleared. To conclude the session, the therapy is stopped, and the machine is powered off and unplugged from the wall.
Essential Cleaning and Maintenance
Maintaining the cleanliness of MIE components prevents pathogen growth and ensures correct machine function. The mask or mouthpiece and the circuit tubing require daily cleaning with mild soap and warm water. These components must be thoroughly rinsed to remove all soap residue and then allowed to air dry completely before they are connected back to the machine.
The air filter, typically near the air inlet, must be checked regularly for dust or contamination. Washable filters should be cleaned in warm, soapy water, rinsed, and air-dried; disposable bacterial filters must be replaced. The exterior surface of the machine can be wiped down as needed with a clean cloth dampened with water and a mild detergent or a 70% isopropyl alcohol solution. Proper storage involves keeping the machine in a clean, dry location, away from direct heat sources, and ensuring the air intake ports are not blocked.
Recognizing Common Issues and Safety Stops
During therapy, a common minor issue is a leak around the mask, which prevents the machine from reaching its set pressure. Adjusting the mask straps or repositioning the interface to achieve a better seal will usually resolve this problem. If the machine displays an informational message or alarm, consulting the user manual’s troubleshooting section can help identify the issue, which might be resolved by simply turning the device off and then back on.
Certain patient symptoms necessitate immediately halting the treatment session. Stop therapy if the patient experiences severe pain, nausea, vomiting, or dizziness during the cycle. If secretions become visible in the mask, pause the cycle, remove and wipe the mask clean, and suction the patient if necessary, before resuming. If the treatment fails to clear secretions, the patient shows signs of increasing respiratory distress, or if the machine is damaged or malfunctioning, contact a medical professional or respiratory therapist immediately.