Weaning from the ventilator

What is the main purpose of a ventilator?

A ventilator can be life-saving but it does not fix the primary disease or injury. It helps support the patient’s breathing while the primary reason for initiating the ventilation is stabilised, improved or treated. The doctors always try to wean the patient off the ventilator at the earliest possible time.

How does a ventilator work?

The ventilator does all the breathing for the patient or assists the patient’s own breathing by blowing oxygen and air into the lungs and extracting out carbon dioxide. To enable this, the doctor sedates the patient with drugs and then introduces a tube called endotracheal tube (ET) tube through the mouth or nose into the windpipe (trachea), a procedure called intubation. Any mucus secretions can be cleared by suctioning out through the ET tube. The tube is connected to the ventilator. If ventilation is likely to be prolonged, the decision may be made to perform a tracheostomy. This is when the doctor makes an opening in the patient’s neck and inserts a tube (smaller than the ET tube) which is then connected to the ventilator.

The tracheostomy is more comfortable for the patient and means that they find it more tolerable. It also means that when the patient is woken, they can communicate more easily. Eventually they will be able to speak with the use of a special valve attached to the tracheostomy. Both the ET and tracheostomy can be easily removed when the patient is better. The hole in the neck from the tracheostomy heals quickly.

How does the patient feel on the ventilator?

The feeling of the tube in the mouth can be uncomfortable. As the tube passes through the vocal cords the patient is unable to speak, which some patients find frustrating. They will not be able to eat or drink, but mouth care and teeth cleaning can be done by the nursing staff. Patients are fed through a tube going into their stomach via their nose. Some discomfort may be felt as air and oxygen blow into the lungs. For the patient’s comfort they are given continuous sedation and pain relief into the vein through a pump. The level of sedation is determined by the treatment purpose.

As the patient improves, the sedation will be weaned off, allowing the patient to take over their own breathing and eventually they will not need the ventilator. At this point the tube will be removed and a simple oxygen mask will be used. The time this can take varies from a few hours to several weeks depending on the severity of their illness.

How is the patient’s progress monitored?

Patients in ICU are constantly monitored to measure heart rate, blood pressure, temperature and oxygen saturations. Other tests include drawing blood to measure oxygen and carbon dioxide levels (blood gases) and blood tests to check kidney function and other body functions. All these blood tests are taken at least once a day. They are reviewed by the nurse at the bedside as well as by medical staff. Ward rounds take place twice as a more formal patient review, but medical staff are in the unit continuously, and the patient has one nurse to care of them at the bedside. This means that the patient can be continuously assessed as to whether they are ready to begin weaning from the ventilator and if they are ready to have the tube removed. As the patient wakes, they are reassured and explanations given about where they are and why.

What risks are associated with ventilation?

Infection is one of the common problems. Although there are ways to reduce the chance of infection, such as mouth care and suctioning the mucus secretions from the lungs the ET tube or tracheostomy can allow germs (bacteria) to enter the lungs, which may cause chest infection. This can delay the patient’s progress and prolong their time on the ventilator. For this reason the staff are keen to wake the patient and wean the ventilation as quickly and safely as possible.

When is sedation stopped?

The doctors may stop sedation altogether or ‘wean’ the drugs slowly. As the patient wakes, the staff can assess how they are progressing and make decisions on reducing the ventilation. Some patients may remain in deep sleep for hours to days after sedation is stopped.

Occasionally a patient may wake up agitated, restless and confused. This may mean the patient is re-sedated and allowed to wake the next day to be assessed again. Staff understand this behaviour is out of character and are there to reassure both the patient and their loved ones. This may take a number of days. Several strategies may also help the patient including relatives talking and updating the patient on their favourite events, reading for them or simply being there. It is fairly common, and will pass.

What is weaning from a ventilator?

Weaning is the process of reducing the ventilator support which may be done quickly or over days to weeks. It is more complex and hard for the patient if they have been on the ventilator for a long time. This process of weaning requires effort from the patient with help from the healthcare team which includes physiotherapists, dieticians, doctors and nurses. Relatives can be a great source of comfort for the patient during this time and can be at the bedside to encourage the patient. All activities require some energy and muscle strength. The physiotherapists draw up a programme of exercises which they do with the patient and nurses. Relatives may also help.

Food is vital to maintain good nutrition and aid recovery. On admission the dietician calculates individual patient requirements and nutrition is maintained by feeding through a tube. Some patients may need intravenous nutrition.

What happens next?

When the medical staff are confident the patient will continue to progress and not require the help of a ventilator again, and the patient has recovering well from any other illness, the process of discharge from the ICU will begin.

This can be an anxious time for the patient and their loved ones, but there is a careful plan made with other healthcare professionals on the wards. Every effort is made to ensure a safe and successful discharge from the unit and eventually home.