By Adam Townsend on 04/01/2020 2:00 PM

Source: MedicineNet Health News

Mechanical ventilation, or breathing machines, might be the best option for people with severe COVID-19 coronavirus lung symptoms.

But ventilators come with their own dangers. Invasive intubation procedures and the placement of tubing in the air canal – sometimes for weeks as with many COVID-19 patients – may introduce bacterial infections, lung trauma, and other serious complications including death, according to Medscape medical reference.

Public health experts have been wringing their hands about the coming shortage of mechanical ventilation units. General Electric, Ford, Philips, Medtronic and other private manufacturers are scrambling to build and develop more machines to help ease the ventilator shortage. Healthcare providers and state governments are stocking up with breathing machines wherever they can find them, as reported widely across major U.S. news outlets.

Still, the details of intubation and mechanical ventilation aren’t familiar to most people who haven’t had severe medical problems in their families already.

What Does a Ventilator Do to Help COVID-19 Patients?

If you have a coronavirus infection that starts compromising your ability to breathe on your own, a breathing machine is your best bet.

Ventilation ensures that your lung tissue receives the maximum amount of air for oxygen-carbon dioxide exchange, according to Medscape. It can also take the pressure off fatigued respiratory muscles as the positive air pressure does the work of expanding the chest.

Breathing support can allow the immune systems of some severely affected COVID-19 patients to fight off the infection before mucus and fluid secretions caused by the SARS-nCoV-2 virus make lungs fail completely, said MedicineNet author and microbiologist .

But intubation – that is, running an air tube into your trachea through your nasal passage – is traumatic and can introduce a different infection simply as a complication of the procedure.

Furthermore, the pressure and volume of air can injure the lungs if it isn’t adjusted correctly, in addition to other serious complications.

These dangers are magnified because many people with advanced COVID-19 who need the hospital-standard, positive-pressure breathing machines need them for weeks at a time.

“What we’re seeing in COVID-19 patients in Asia, Italy and the U.S. is that when patients do end up being ill enough to be admitted to the ICU, they need to be intubated and remain on a ventilator for two to three weeks, which increases the demands for ICU beds and ventilators dramatically,” Dr. Steven Choi of Yale School of Medicine told CNN March 27.

When Do COVID-19 Patients Need a Breathing Machine?

COVID-19 causes mucus and fluid to block oxygenation of lung tissue in the sickest patients, preventing the exchange of oxygen and carbon dioxide from the bloodstream.

According to Medscape, the indications for starting mechanical ventilation in a patient are:

  • Abnormally slow breathing (bradypnea)
  • Cessation of breathing (apnea)
  • Abnormally rapid breathing (tachypnea)
  • Inefficient exchange of gases
  • Respiratory muscle fatigue

How Is the Mechanical Ventilation Procedure Performed?

In general, doctors perform invasive ventilation in two procedures, depending on the patient and their condition, according to Medscape:

A tracheostomy, or surgical opening in the airway through the throat, is usually done for one of the following reasons, according to MedicineNet author :

  • to bypass an obstructed upper airway (an object obstructing the upper airway will prevent oxygen from the mouth to reach the lungs);
  • to clean and remove secretions from the airway;
  • prolonged mechanical ventilation (breathing machine); and
  • to more easily, and usually more safely, deliver oxygen to the lungs.

Once a person is intubated, positive-pressure ventilators push the air into the patient’s airway. The ventilator continually blows and stops in regular, preset cycles, enabling the lungs to receive oxygen and expel carbon dioxide, Medscape states.

Positive-pressure ventilators may be:

  • Volume-controlled: delivers a preset volume of air into the patient’s trachea even if it entails high airway pressure. When the flow is stopped the chest recoils and expels the air out.
  • Pressure-controlled: delivers air till the airway pressure limit is reached and the valve opens to expel air. The volume of air delivered may vary depending on the airway resistance and lung capacity.
  • Dual control: these combine the advantages of volume control and pressure control and deliver airflow based on the requirement and response of the patient.

Beside ventilation, the other benefits of intubation are:

  • Bronchoscopy: examining the lung with a bronchoscope inserted through the breathing tube.
  • Aspiration: suction of fluids to keep the airway clear.
  • Medication: aerosolized medications more effectively delivered directly to the airway or lungs.

If I Get Put on a Ventilator With COVID-19, Will I Survive?

If you can’t breathe on your own, a ventilator may keep you from dying, but it’s not a cure. Ventilators that require intubation – the only kind clinicians can use on COVID-19 patients as of late March – are quite invasive.

The longer you stay on a ventilator, the more you risk complications from the intubation and ventilation, according to Medscape.

Invasive ventilation complications include:

  • bacterial lung infection,
  • trachea narrowing and tissue death,
  • trauma to the airway membranes,
  • barotrauma (injury from too much air pressure)
  • volutrauma (lung injury from too much air volume)
  • inability to wean off the ventilator
  • death

Can Hospitals Use CPAP Machines for COVID-19 Breathing Support?

No; doctors would probably infect more people by putting a COVID-19 patient on a CPAP machine. Intubation, or invasive ventilation, is currently the only approved clinical method of providing breathing support to COVID-19 patients.

A CPAP (continuous positive airway pressure) machine used commonly for sleep apnea may be able to provide enough oxygen for some patients, and it is non-invasive. The air supply in a CPAP machine comes through a face mask or nasal prongs strapped around the patients head with no intubation necessary.

But the American Society of Anesthesiologists’ clinical guidelines published late February warn against using CPAP machines for COVID-19 patients. The machine aerosolizes the virus in the patient’s breath and spreads it all over whatever facility the patient is housed in.

Experts believe this was a problem in the Life Care Center of Kirkland, a Washington-state assisted living home in which 24 percent of the residents succumbed to COVID-19 coronavirus infections.

Local emergency officials in Washington told NPR March 27 that CPAP machines were standard for paramedics to use on people who show signs of respiratory failure, and they used CPAP on Kirkland residents during 911 calls.

Emergency officials have changed CPAP recommendations in light of this concern, according to NPR.

How Did They Invent Breathing Machines?

Before the development of positive pressure ventilation, people with breathing problems were held in a negative-pressure ventilation machine called an iron lung.

The iron lung is a stationary chamber that seals in the patient from the neck down. Changes in the air pressure inside the chamber force the chest to expand and contract, according to Medscape. Iron lungs were most often used in people suffering polio-related paralysis.

Researchers before 1950 also developed a sort of portable iron lung called a cuirass. This was an iron chamber that fit around a patient’s torso and administered negative pressure through a bladder inside, Medscape states.

Both these negative-pressure devices were cumbersome, and also affected the gut, stomach and other organs.

Positive-pressure ventilators were invented in the early 1950s to treat polio patients with respiratory paralysis. Though machines have improved since the 1950s, the principle is the same.

What Are the Risks and Complications of Being Put on a Breathing Machine?

Mechanical ventilation has a few risks and complications that can sometimes be life-threatening, as mentioned above. The complications can arise during intubation or with ventilation, according to Medscape.

Complications of intubation:

  • Upper airway and nasal trauma
  • Tooth displacement (avulsion)
  • Injury to the mouth, throat, vocal cords or trachea

Prolonged intubation might cause:

  • sinusitis
  • tracheal narrowing (stenosis) or tissue death (necrosis)
  • edema in the vocal cords
  • infection in the respiratory system
  • pneumonia
  • sepsis in the bloodstream

Complications of ventilation may include:

  • Ventilator-induced lung injury leading to alveoli rupture and lung collapse (pneumothorax) from barotrauma or volutrauma
  • Oxygen toxicity from too much oxygen
  • Ventilator-assisted pneumonia caused by bacterial and viral infections in the lung
  • Medication side effects and reactions
  • Effects on other organs such as blood circulation, heart, kidneys, abdomen
  • Ventilator malfunction
  • Inability to wean off from the ventilator
  • Sepsis
  • Death



Source link