Mechanical ventilation is the last resort in many cases. In other words, doctors usually recommend mechanical ventilators when other treatment options have failed. While these machines are mainly associated with severe diseases and injuries, they have other applications too. This post focuses on the relationship between mechanical ventilation and congestive heart failure. Can it help patients with this heart problem? Conversely, can mechanical ventilation damage the heart? Read on to learn more.
What is congestive heart failure?
Congestive heart failure, also known as heart failure, is when the heart fails to pump blood efficiently. Although the name would suggest otherwise, congestive heart failure doesn’t mean the heart literally fails or is about to stop functioning.
When the heart doesn’t pump blood properly, blood tends to back up. This leads to the accumulation of fluid in the lungs. As a result, patients experience shortness of breath. Other symptoms of heart failure include:
- Irregular or rapid heartbeat.
- Swelling of the abdomen.
- Swelling in legs, ankles, and feet.
- Persistent wheezing or cough with blood-tinged mucus.
According to the CDC, about 6.2 million adults in the United States have heart failure. The main risk factors for heart failure include coronary artery disease, hypertension, diabetes, obesity, valvular heart disease, and other conditions associated with heart disease.
What is mechanical ventilation?
Mechanical ventilation is a type of life support. The mechanical ventilator machine takes over the breathing process when a patient is unable to breathe enough. Main indications for mechanical ventilation are airway protection in patients obtunded by hypercapnic respiratory failure due to a reduction in minute ventilation, among others. One important application of mechanical ventilation is for cardiovascular distress. In these cases, mechanical ventilators offload the energy requirements of the breathing process.
Can mechanical ventilation help patients with congestive heart failure?
Congestive heart failure can lead to a wide range of complications, including liver damage, kidney damage or failure, heart valve problems, and heart rhythm problems. Proper management of congestive heart failure is crucial for the prevention of unfortunate scenarios. The treatment depends on the underlying cause and other factors in most cases. The use of medications, surgery and other procedures are the most common treatment approaches.
Mechanical ventilation could be helpful as well.
A study from the Journal of Cardiovascular Development and Disease confirms mechanical ventilation is a life-saving strategy for respiratory failure, including decompensated congestive heart failure. Ventilation can decrease the work of breathing, lower preload and afterload of ventricles, and reduce the level of extra-vascular lung water in congestive heart failure.
The effects of mechanical ventilation, specifically positive and expiratory pressure, supplemental oxygen, and inspiratory support, are beneficial for recovery from left ventricular dysfunction. In decompensated heart failure patients, mechanical ventilation offers various benefits ranging from reducing cardiac afterload resulting in decreased oxygen demand in the left ventricle and higher cardiac output, reducing the work of breathing, thereby reducing requirements associated with cardiac output. In addition, mechanical ventilation in persons with decompensated heart failure can also improve oxygenation of the myocardium and hypoxia-induced pulmonary vascular constriction.
Proper use of mechanical ventilation should be observed as a beneficial supplemental therapy in the initial stages of management and stabilization of decompensated heart failure patients and persons with acute respiratory failure. That being said, special attention should be paid to patients with decompensated heart failure in terms of liberation from the machine and weaning off the ventilator since heart failure is among the risk factors for extubation failure. It may also increase the need for re-intubating a patient.
Although the abovementioned study focused on decompensated heart failure, it did show that patients with heart failure could benefit from mechanical ventilation.
The European Respiratory Journal published a study that explored the impact of assisted ventilation for heart failure patients with Cheyne-Stokes respiration, a condition that causes abnormal breathing during sleep. Results showed that bilevel ventilation was equally effective as continuous positive airway pressure in patients with congestive heart failure. In addition, the treatment improved sleep quality, reduced daytime fatigue, and increased circulation time.
To sum up, mechanical ventilation can be helpful for patients with congestive heart failure. However, this approach is not suitable for all patients with congestive heart failure. Despite the potentially positive impact, it’s also helpful to bear in mind it’s necessary to wean off a patient from a ventilator carefully to avoid complications.
Can mechanical ventilation cause congestive heart failure?
While mechanical ventilation can improve gas exchange, reduce the work-cost of breathing, and allow respiratory muscles to rest, it can also change cardiac output. This is because ventilators can also modify blood flow distribution.
Since mechanical ventilation relieves the respiratory muscles, it contributes to a reduction in whole-body oxygen consumption. This leads to a limited cardiac output that subserves other metabolic demands.
Evidence shows weaning from mechanical ventilation could induce cardiovascular stress as well as heart failure and pulmonary edema in some cases. In addition, the weaning process affects left ventricles in some patients. This is particularly the case with critically ill ventilator-dependent patients.
How long do patients need to be connected to a mechanical ventilator?
Every patient is different. For that reason, the duration of mechanical ventilation may vary from one person to another. Some patients may need to be on a mechanical ventilator for a few hours only. Others need to be connected to the ventilator longer, a few days or weeks. The duration of this procedure depends on the severity of the disease and symptoms a patient experiences.
Benefits and risks of mechanical ventilation
The primary advantage of mechanical ventilation is that a patient doesn’t have to work hard to breathe. The machine allows their respiratory muscles to rest. Doctors recommend mechanical ventilation to allow patients time to recover, hoping their breathing will improve. These machines also clear carbon dioxide and help patients get enough much-needed oxygen. Since mechanical ventilation preserves a stable airway, it can prevent injury from aspiration.
Speaking of the benefits of mechanical ventilation, it is essential to remember that it doesn’t heal the patient. Instead, the ventilator gives the patient a chance to stabilize while treatments and medications work on their recovery.
The main risk associated with mechanical ventilation is infection. This is because the breathing tubes could allow germs and other pathogens to enter the patient’s lungs. The risk of infection increases with the duration of the ventilator use, which is why it’s at its highest at about two weeks. Besides infection, another potential risk is lung damage. Lung damage could result from over-inflation or repetitive opening/collapsing of small air sacs in the lungs.
As seen throughout this post, mechanical ventilation can help some patients with heart failure and improve their functioning. However, this approach is also prone to various risks. The role of mechanical ventilation in congestive heart failure requires more research. At this point, studies on this subject are scarce. This isn’t convenient, considering that heart failure is a common cardiovascular problem.