When a new medical therapy, such as a novel ventilation strategy, is developed, it must first be thoroughly tested to make sure it is safe and effective. To prove this, researchers design and conduct clinical trials. A clinical trial must be approved by the local government and reviewed by an independent ethics committee before including a limited number of patients who have given their informed consent. You are being asked to participate in the ViPS Trial. This trial is designed for patients who suffer from respiratory insufficiency and are on controlled mechanical ventilation for more than 24 hours. The ViPS Trial will include roughly 228 patients in about 12 medical centers around the world. The follow-up time will be 6 months after your hospital discharge. Clinical studies typically require a control group for comparison to the investigational group, and this trial is no exception. In the ViPS trial, patients receiving variable pressure support ventilation (the new ventilation strategy) will be compared to patients receiving non-variable pressure support ventilation, which is currently the most commonly used mode of assisting the patient’s effort to breathe. The purpose of the ViPS Trial is to investigate whether variable pressure support leads to a shorter period of total ventilation time. What is the difference between variable and non-variable pressure support ventilation? Non-variable pressure support ventilation (PSV) is one of the most commonly used modes of assisted ventilation worldwide. PSV is a ventilatory strategy which supports spontaneous breathing efforts with a fixed amount of positive airway pressure by the mechanical ventilator. In other words, in non-variable PSV, pressure support is constant breath-by-breath, and will be adjusted according to individual needs. Variable pressure support ventilation is a further development of the conventional PSV mode. The mean pressure support is equivalent to that used in conventional PSV, but single values vary randomly from breath to breath.

When a patient suffers from respiratory insufficiency, mechanical ventilation may be required to support breathing. There are numerous ventilatory strategies, and your physician will decide with one is appropriate for you based on your individual needs. If you agree to participate in this trial, you will be treated with either of the following strategies:

• Variable pressure support ventilation
• Non-Variable pressure support ventilation (conventional PSV)

To date, it is unknown which of these ventilation modes is best, but we have reasons to believe that the new strategy (variable pressure support ventilation) may be superior. The trial is designed to prove this. An important part of making a fair comparison is “random allocation”. When a patient is enrolled in the ViPS Trial, a computer algorithm makes sure there is an equal chance (50%) of receiving either the new therapy (variable pressure support) or the standard therapy (non-variable pressure support). The researchers and your physician have no influence whatsoever on this decision. During the trial, you will receive daily visits by our researchers while you are still connected to the mechanical ventilator in the intensive care unit (ICU). At each visit, your treating physician will complete a questionnaire about the details of your treatment. Other relevant medical data will be recorded in the trial database for later analysis. As follow-up, you will receive telephone calls at 28 days, 90 days and six months after your hospital discharge. The trial does not involve any additional medical procedures or test apart from the ones your treating physician deems necessary. Your treatment will follow international standard patient guidelines.

What will I need to do if I decide to take part in the ViPS trial? If you decide to take part in the trial, you will be asked to:

• Read and sign an informed consent form
• Schedule and agree to follow-up telephone calls
• Answer additional questions at follow-up
• Report any problems to your treating physician

The purpose of the ViPS trial is to investigate the safety and effectiveness of the variable vs. non-variable PSV. As with all new technologies, there are potential benefits and risks associated with the new therapy. Variable PSV is already commercially available and approved for clinical use. Thus, physicians are allowed to use variable PSV at their own discretion and several patients have been already ventilated with this new mode. Compared to non-variable PSV, variable PSV has been shown to improve gas exchange, respiratory mechanics and breathing comfort, as well as to reduce inflammatory blood markers in preliminary experimental studies. We do not expect any disadvantages or risks associated with the variable ventilation strategy compared to the standard non-variable therapy. The use of variable pressure support ventilation therapy might improve the outcome of acute lung injury. We cannot promise that the trial will benefit you personally, but the trial results should help improve the future treatment of other patients like you with respiratory insufficiency. Experience suggests that patients benefit from participation in trials of this kind due to intensified observation and follow-up by the researchers.

You DO NOT have to consent. It is your free decision whether or not to participate. If you do decide to take part, you will be asked to sign a consent form. It is important for you to understand that you may withdraw your consent at any time during the trial without stating your reasons. If you decide to withdraw your consent, or decline your consent now, this will in no way affect the care you receive from our healthcare providers.

Participation in the trial is completely voluntary. Even after you have agreed to participate, you can withdraw your consent at any time. The information collected up until the time of your withdrawal may still be used. This is important for the integrity of the trial. You can withdraw your consent at any time without negative consequences for you or the care you receive from your physician. It is important that you carefully consider all of your treatment options before giving your consent.

All research protocols that are conducted in patients are reviewed carefully by an independent research ethics committee, which aims to protect your safety, rights, well-being and dignity. This trial has been approved by the ethics committee that is responsible for your hospital.

If you decide to participate in the ViPS trial, your medical information will be forwarded to the Coordinating Centre for Clinical Trials (CCCT) at the Medical Faculty of the Dresden University of Technology, Germany, which is coordinating the trial. However, YOUR NAME WILL NOT be reported to the coordinating center. Occasionally, staff from local regulatory authorities in your country may visit your hospital to review your records and confirm that the information being provided is correct. Physicians involved in your care will be kept fully informed, but otherwise all information about you and your treatment will remain completely confidential. We need to keep your name and address on file for the follow-up, but this information will be stored separately from your medical data. Everyone involved in the trial has a duty of confidentiality to you as a research participant.