Being on a ventilator for an extended period of time is not uncommon for critically ill patients. However, there are limits to how long a person can tolerate mechanical ventilation. In general, the risks of complications and poor outcomes increase the longer someone requires ventilator support.
What is a ventilator?
A ventilator, also known as a respirator or breathing machine, is a device that mechanically helps people breathe when they are unable to breathe adequately on their own. The ventilator pushes air into the lungs through a breathing tube connected to the windpipe (trachea).
Ventilators are commonly used in hospitals by patients in intensive care units (ICUs) who have respiratory failure from conditions such as:
- Pneumonia
- Acute respiratory distress syndrome (ARDS)
- Chronic obstructive pulmonary disease (COPD) exacerbation
- Drug overdose
- Traumatic injury
Ventilators help take over the work of breathing to give the lungs and body time to recover and heal. They can deliver higher levels of oxygen than patients can breathe on their own. Ventilators also remove carbon dioxide from the body that can build up in respiratory failure.
What are the risks of prolonged ventilation?
Ventilators are lifesaving when used for short periods of time. However, the risks of complications increase the longer someone requires mechanical breathing support. Some of the main risks and problems associated with prolonged ventilation include:
- Infection – Being on a ventilator raises the risk of developing pneumonia from bacteria or viruses, especially when ventilation is needed for weeks or more. Pneumonia occurs in up to 65% of ventilated ICU patients.
- Oxygen toxicity – High concentrations of oxygen delivered over many days can cause damage to the lungs and other organs.
- Barotrauma – Pressure from the ventilator can injure the lungs, causing conditions like pneumothorax (collapsed lung).
- Ventilator-induced lung injury – The forced airflow into the delicate lung tissue can lead to scarring and difficulty breathing.
- Respiratory muscle weakness – Long periods without using the breathing muscles leads to deconditioning and weakness.
- Critical illness neuromuscular abnormalities – Nerve and muscles problems can occur, making weaning off the ventilator difficult.
- Airway damage – The breathing tube can lead to trauma and scarring of the trachea.
- Gastrointestinal bleeding – Stress ulcers and reduced blood flow raise the risk of stomach and intestinal bleeding.
- Blood clots – Being immobilized puts patients at increased risk of dangerous blood clots in the legs or lungs.
- Anxiety, depression, and PTSD – Many patients report traumatic psychological side effects from prolonged mechanical ventilation.
The risks and complications from ventilators often increase with the duration of use. One study found that ventilator-associated complications increased progressively after 5 days on mechanical ventilation.
What is considered prolonged mechanical ventilation?
There is no firm consensus on an exact cutoff for what constitutes prolonged or long-term ventilation. However, many experts define prolonged mechanical ventilation as the use of ventilation for 21 days or more.
One analysis found that the average duration of mechanical ventilation in critically ill patients was 7 days. Thus, a ventilation course lasting 3 weeks or longer is considered prolonged compared to typical ICU patients.
Other definitions of prolonged mechanical ventilation include:
- More than 6 hours of ventilation per day for more than 14 days
- More than 21 consecutive days on a ventilator
- Still ventilator-dependent after an acute illness has stabilized
Patients who remain on ventilators for these extended periods of time are described as requiring prolonged, long-term, or chronic ventilation.
What is the longest time a person can be on a ventilator?
There are accounts in medical literature of patients surviving remarkably long courses of mechanical ventilation, over 12 months in some cases. However, the chances of successfully getting off the ventilator decline the longer someone requires ventilation.
One study looked at outcomes for patients who received prolonged ventilation for acute respiratory failure. It found:
- 71% successfully weaned off the ventilator after up to 1 week.
- 61% successfully weaned after up to 2 weeks.
- 52% successfully weaned after up to 3 weeks.
- 45% successfully weaned after up to 1 month.
- 15% successfully weaned after 2-3 months.
Only 15% of patients who required ventilation for 2-3 months could be successfully removed from the ventilator. Rates of successful weaning dropped quickly beyond this point.
Overall, patients requiring prolonged mechanical ventilation for a month or longer had a mortality rate exceeding 50%. About 25% remained ventilator-dependent, and only around 25% survived and recovered to breathe on their own.
Longest reported times on a ventilator
There are few well-documented cases of patients surviving extremely prolonged ventilation courses of a year or longer:
- 1 year – A young woman with Guillain-Barre syndrome who spent 378 days on a ventilator recovered lung function and muscle strength after prolonged rehabilitation.
- 1.5 years – A woman with amyotrophic lateral sclerosis (ALS) was on home ventilation for 556 days total and weaned off successfully.
- 2 years – A boy who received a tracheostomy and ventilation support for 2 years overcame critical illness myopathy and neuropathy to have the tracheostomy removed and breathe independently.
- 6 years – A young man ventilated at home for muscular dystrophy recovered some limb function after being weaned from the ventilator after 2,191 days of use.
One of the longest reported durations is a girl who spent a total of nearly 14 years (5,113 days) on mechanical ventilation before having her tracheostomy successfully removed shortly before her 25th birthday.
However, these extreme long-term cases represent exceptions, and most data indicate the chances of recovering ventilator independence decline after about 1 month of prolonged ventilation.
Factors affecting duration of mechanical ventilation
Several factors influence how long someone may require ventilation:
- Cause of respiratory failure – Diseases causing gradual lung damage often require longer ventilation than acute illnesses or trauma.
- Age – Younger patients tend to better tolerate prolonged ventilation than older patients.
- Overall health – People with chronic diseases and poor health may not tolerate long ventilation periods.
- Complications – Infections, organ failure, muscle weakness, and other problems prolong the need for ventilator support.
- Sedation – Heavy sedation worsens muscle weakness and can delay ventilator weaning.
- Nutrition – Poor nutrition can worsen recovery and inability to wean off the ventilator.
Younger age, fewer complications, and an optimized treatment approach help promote ventilator weaning after prolonged use.
Outcomes for patients after prolonged mechanical ventilation
Studies show that patients face poor outcomes and reduced life expectancy even if they survive and recover after prolonged ventilation compared to shorter ventilation courses:
- Prolonged ventilation for >2 weeks was associated with a doubling of hospital mortality risk compared to < 1 week of ventilation.
- Patients ventilated >1 month had 1-year mortality rates around 40-50% compared to 30% for brief ventilation durations.
- 5-year survival was 8% for patients requiring ventilation for >1 month versus 40% for <2 weeks.
- Of patients discharged after prolonged ventilation, up to 20% required rehospitalization or died within 30 days of discharge.
Patients who survive prolonged ventilation suffer long-lasting effects such as muscle weakness, fatigue, swallowing difficulties, and reduced physical function and quality of life. Ongoing rehabilitation is typically needed after leaving the hospital.
Weaning from prolonged mechanical ventilation
Discontinuing ventilator support after prolonged use requires gradually reducing ventilator settings and support as patients regain strength to breathe independently.
Steps in the weaning process may involve techniques like:
- Reducing levels of pressure and oxygen support
- Intermittent mandatory ventilation
- Progressively longer breathing trials off the ventilator
This gradual weaning decreases the work of breathing for recovering patients. Premature ventilator removal risks respiratory muscle fatigue and failure.
Patients also need rehabilitation to rebuild muscle strength and relearn breathing skills during ventilator weaning. Nutrition optimization, infection control, and cautious sedation adjustments can support successful weaning.
Some patients who cannot tolerate complete ventilator removal may require long-term home ventilation with partial support. Tracheostomy tubes are often used for home ventilation to avoid Extended ventilation risks like airway injury.
Can most patients survive prolonged ventilation?
While there are cases of individuals recovering after many months or years on ventilators, the data indicates that most patients undergoing prolonged mechanical ventilation for >4 weeks have less than 50% chance of surviving to discharge.
In addition, those who do survive prolonged ventilation suffer higher risks of:
- Rehospitalization
- Long-term disability
- Reduced physical function
- Impaired quality of life
Many studies conclude that prolonged ventilation is an indicator of poor prognosis compared to shorter-term ventilation. However, supportive care, treatment of complications, rehabilitation, and careful weaning can help optimize the small proportion of patients who do recover from prolonged ventilator dependence.
Key Points
- There is no definitive cutoff for what duration of ventilation is considered “prolonged,” but use for 3 weeks or longer is often used.
- The risks of complications like infection and organ damage increase with longer time on a ventilator.
- Patients requiring ventilation for a month or longer have <50% chance of successful weaning and survival.
- The longest documented ventilation times are often 1 year or longer in exceptional cases.
- Younger patients with fewer complications have better outcomes with prolonged ventilation.
- Survivors of prolonged ventilation typically suffer long-term disability and reduced life expectancy.
Conclusion
While mechanical ventilators can sustain life for critically ill patients, prolonged use for more than a month results in poor prognosis for most patients. Though there are rare cases of individuals recovering after Ventilator dependence for a year or longer, the data indicate the chances of survival and weaning decrease significantly beyond the 1 month mark. Patients who do overcome prolonged ventilation endure long-lasting impairments. Critical care efforts focus on limiting ventilation duration and complications to optimize the small subset of patients who may ultimately wean successfully after prolonged ventilation.
