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Wednesday, December 19, 2012

What is a ventilator?

A ventilator is a machine that breathes for you when you're intubated or trached. Most are set up in emergency rooms and critical care units in hospitals, but some patients require home ventilators.

Ventilators are machines that provide positive pressure breaths. Most modern ventilators are microprocessor ventilators that offer essentially two different modes:
  1. Control. The machine does all the breathing. This is necessary when a person is very sick, such as during severe COPD flare-ups, severe pneumonia, head trauma, heart attacks, or surgery. Such modes are usually necessary short term, allowing the person to completely rest while doctors work their magic. When in such modes, a paralytic is often necessary, along with a sedative to create an amnesia affect. 
  2. Spontaneous. Once you start to wake up, modern ventilators will sense this, and the ventilator will automatically switch over to a spontaneous mode. These modes will provide a set pressure to assist with breathing, although the patient will have complete control of when breaths are given. This makes being on a ventilator much more comfortable for patients, as they will not be given breaths when they are not ready for them. Sedatives are usually indicated here to take the edge off the discomfort of being intubated and create an amnesia affect. 
Ventilators are most often used only short term. For people with severe shortness of breath due to severe asthma or COPD, often noninvasive forms of ventilation (such as BiPAP) are trialed first. If these fail to work, then a person can be intubated if needed and placed on a mechanical ventilator. Fortunately, success with BiPAP has greatly reduced the need for COPD patients requiring intubation. Still, it's available when needed.

The process of getting a person off a ventilator is called weaning. Usually we will want to remove sedatives at this time to have you fully awake.We do this so we have your full cooperation and so we can assess your readiness for weaning. Usually we go through a series of tests, such as breathing tests. We will also want to make sure you do well in spontaneous mode. This will usually involve removing any support provided by the ventilator, other than the minimal support needed to make up for breathing through ventilator tubing.

Modern protocols have it so that respiratory therapists, nurses, and doctors start thinking wean as soon as you are put on the ventilator. Of course, the doctor must assure the team that your underlying condition that made you so sick is resolved. And, of course, we will talk you through the entire process so that you are well aware of what is going on. When all looks good, we extubate you (pull the tube from your airway).

Our testing is usually so complete today that most people are able to breathe just fine on their own without the ventilator. And just keep in mind that ventilators do not cause any pain, it's just that you have a tube in your airway and this may be a little uncomfortable. So, this is why, when you are on a ventilator, you are usually given a sedative to take the edge off.

As I interview patients who were intubated, I find that almost all of them, even though they were very compliant and cooperative during the weaning process, had no memory of it. So, this, I would say, is a good thing. While it's a necessary thing to get people feeling better, it's not something you want to remember.

Some patients have muscle or nerve diseases that make it so their muscles of respiration do not work.  These patients may require a full time ventilator that they can use at home and when they travel.  These ventilators are generally small and easy to set up and use.

Hospital ventilators are generally larger and have a full set of alarms. I usually tell people in the room with the patient, and the patient too, not to worry about alarms when they go off. We usually have them set so that we know when the patient wakes up, or when the patient is coughing. Of course, the alarms are also useful so we know if something is wrong too.

If you are curious as to the indications for intubation and mechanical ventilation, you can check out my post, "Indications for Mechanical Ventilation" and "Indications for Intubation."


Anonymous said...

Picture is wrong... RT periodically checks the vent...

Rick Frea said...

That's funny. I didn't even notice that.