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Wednesday, December 23, 2009

Indications for BiPAP

Non-invasive positive pressure ventilation (NIPPV) include machines that allow you to ventilate and oxygenate patients without the need to perform the invasive procedure of intubation. These machines can only be used on a spontaneously breathing patient.

Another acronym commonly used to describe NIPPV is NIV, which essentially stands for Non-Invasive Ventilation. You may actually see other similar acronyms, and they all essentially refer to the same thing.
The two most common forms of NIV are:
  1. CPAP 
  2. BiPAP 
So, what are they and how might they help your patients?
1. CPAP: This is continuous positive airway pressure. It's a pressure exhale applied during the respiratory cycle that helps keep air passages open so that the next breath comes in easier. Since it keeps the airways patent, it assures adequate oxygenation, and is often prescribed to increase oxygenation.

Indications for CPAP.
  • Hypoxemia that is refractory to high concentrations of oxygen by other means. 
  • Obstructive Sleep Apnea to prevent the upper airway from collapsing 
Adjusting CPAP settings. CPAP is increased or decreased to maintain a desired SpO2, which is usually greater than 90% SpO2 and 60 PaO2.

BiPAP: This is an acronym for Bi-level (or Biphasic) Positive Airway Pressure. It provides a combination of both IPAP and EPAP.
  • IPAP. This is Inspiratory Positive Airway Pressure. It is a pressure during inspiration that assists a patient obtain an adequate tidal volume. Because it provides assistance with inhalation, it therefore decreases the work of breathing required to get air in. Because it assures adequate ventilation, it is often prescribed to blow off carbon dioxide (CO2). 
  • EPAP. This is Expiratory Positive Airway Pressure. It is the same thing as CPAP. EPAP is simply used here so you know your talking about CPAP on a BiPAP machine. EPAP is used to improve oxygenation.
Indications for BiPAP.
  • Respiratory Failure due to accessory muscles fatigue. It assures adequate ventilation to blow off CO2 and improve oxygenation. 
  • COPD to decrease airway resistance, thereby decreasing work of breathing required to take in an adequate tidal volume. By increasing ventilations, it helps to blow off CO2. It also keeps airways patent to improve oxygenation. 
  • Pulmonary Edema to help decrease cardiac output which decreases venous return to the right ventricle to reduce blood return to the heart. It also keeps airways patent to help improve oxygenation. It also helps keep alveoli patent to improve oxygenation (prevents alveolar collapse). By keeping alveoli patent, and redistributing alveolar fluid, it helps to reduce pulmonary compliance and reduce work of breathing. 
  • Atelectasis to help keep airways patent to improve oxygenation 
  • Pulmonary Embolis to improve oxygenation 
  • Pneumonia to assure adequate ventilations and oxygenation

Adjusting BiPAP settings. As a rule of thumb, the following rules are true.
IPAP. Increase to blow off CO2. It should not be higher than 20 to prevent pressure from blocking the esophagus. By providing adequate tidal volumes it may also help improve oxygenation.

EPAP. Increase to improve oxygenation.

PS. Pressure Support. This is the gap between IPAP and EPAP. The greater the PS is the more CO2 will be blown off.

Patient Leak. It is important to have a small leak to prevent skin breakdown. Most modern machines will compensate for a small leak.

Alarms. Adjusted as appropriate for each patient.

Contraindications for BiPAP include.
  • Inability of patient to protect own airway (decreased level of consciousness). This includes the inability of the patient to pull off the mask if it becomes full of fluid, such as vomit or spit. 
  • Increased secretions (i.e. pulmonary edema, increased sputum production) 
  • Any patient at risk of vomiting (post stomach surgery, drug overdose). In this case you may be able to use BiPAP if an NG is inserted. Most machines will compensate just fine for the leak around the tube. 
  • Bullous lung disease (emphysema) because the high pressure may cause a pneumothorax 
  • Pneumothorax may be complication due to increased pressure;;may blow out rest of good lung 
  • Hypotension; High pressures decrease cardiac output 
  • Non-compliant patient. Surely you cannot force a patient to use this equipment. 
Study ResultsStudies show that the use of NIPPV for respiratory failure in COPD patients results in a greater reduction in CO2 and a normalization of pH, compared to those in the control group who did not use NIPPV. A study also showed those receiving conventional therapy were intubated 67% of the time, while those receiving NIPPV were intubated only 9% of the time. This prevents the complications of mechanical ventilation, particularly the difficulty associated with extubating patients with lung disease.

Studies also show that length of stay in a hospital is reduced among the COPD pupulation using NIPPV. NIPPV may also be used on the medical/ surgical floors, reducing cost. However, those in severe respiratory failure may still require a stay in the critical care unit.

Studies also show that most patients, or about 80%, tolerate NIPPV just fine. (see references #3 and 4 below).

Bottom Line. Non-Invasive Positive Pressure Ventilation machines are ideal for many patients to improve oxygenation and ventilation. They have prevented many critical patients from having to go through the invasive procedure of intubation and mechanical ventilation. They are also useful to assure adequate ventilation and oxygenation in the home setting, especially during the nighttime when breathing seems to be more relaxed.

This post was originally published on 8/4/8 on; it has been edited for accuracy.

Further Reading.


Matt said...

"I have seen BiPAP ordered on patients that do not fill the above indications. The following are some examples: Pulmonary edema to force the fluid out of the lungs (CHF and pneumonia"

While BIPAP does not "force" the fluid out of the lungs, it's usage in treating acute pulmonary edema has been well documented in the critical care setting.

A high level of EPAP (ie + 1O, + 12) acts to decrease venous return thus decreasing ventricular preload and allows time for the left Ventricle to "pump" the pulmonary edema out of the lungs.

Anonymous said...

I heard bipap helps bradycardia....any thoughts on this?

Rick Frea said...

Never heard anything about that. Have you seen any studies?

Anonymous said...

Gollee gee willikers....

Respiratory therapists are so smart, and doctors are so dumb. We know nothing about respiratory care.

Is that the (nonsensical) point you're trying to make with your little quips about doctor 'mistakes'?

Perhaps you don't know as much as you think you do. Go to medical school, and find out for yourself.

Rick Frea said...

If I thought I was smarter than a doctor I'd be a doctor. The whole reason the respiratory profession was created (BY A PHYSICIAN) was because respiratory therapy was beyond the scope of the physician's knowledge (quote by EGAN). We RTs are the experts in respiratory therapy. That's all we do. We study it. We eat it. We live it. We are a part of the patient care team, and it's our job to make recommendations to the physician. Then the doctor makes the final decision. If anything, the reason I write stuff like this is our of respect for the medical profession.

Rick Frea said...

Thats respect for the medical profession, and respect for the patient. BiPAP is not fun to wear. And We RTs just want to make sure if it's going to be used, the doctor is aware of the facts.

Anonymous said...

Comments by the previous anonymous poster sound defensive, childish and quite unexpected from a physician.

Rick Frea said...

True, and it was anonymous, so it probably wasn't even a physician.

Anonymous said...

I have a relative recently put on BiPAP. He has Bullous Lung disease and you list this as a contraindication. Would you please post a medical reference so that I may educate myself before I consult the physician. Thanks

Anonymous said...

Hi. I think I misread your contraindication list. The contraindication was for bullous lung disease pneumothorax, not just bullous lung disease. If I'm wrong please post. Thanks again for an informative block on NPPV.

Anonymous said...

We use BiPap for acute pulmonary oedema all the time in conjunction with frusemide to extremely good effect. Why do you feel this is not an appropriate management?

Rick Frea said...

I am not opposed to BiPAP for heart failure. I am opposed to the myth that BiPAP will somehow force fluid out of the lungs. This is not true, as BiPAP decreases cardiac output and helps by that means. I added a link to the post if you wish to check it out: the 17 biggest myths of respiratory therapy. I explain this in more detail in the post. Thanks.

Robert22 said...

I work at a hospital where a physician orders Bipap, on 2 hrs, off 2 hrs as a therapy. Usually the patient has pneumonia or plural effusion. Any thoughts.

Anonymous said...

I was wanting to know if there is anyway to check the history of when changes to settings were made?

john bottrell said...

Not for any bipap machine I have ever used. Why?

Unknown said...

I had to laugh at the annoy a patient thing (raise blood pressure) because my use of BiPAP and CPAP is that CPAP is annoying and BiPAP a comparative dream machine.

JimG said...

I am a long-time user of a BIPAP machine. Is anyone aware of any long-time negative effects of using this machine? Recently (past 6 months or so) I have been experiencing a shortness of breath.

john bottrell said...

Generally, if your physician has prescribed BiPAP for you, he believes there are more serious negative effects if you don't use it exactly as prescribed. If you think your BiPAP is not working properly, it's important to have it checked. Otherwise, if you are experiencing shortness of breath, it's important that you call your physician right away.