Blood Pressure Crash Course for nurses

Blood Pressure Crash Course for nurses

William J. Kelly, MSN, FNP-C
William J. Kelly, MSN, FNP-C

Author | Nurse Practitioner

Blood pressure is one of the 5 vital signs, and it is so important to understand what normal and abnormal blood pressures are, and how we manage them (don’t get me started on the “6th” vital sign…).

Within the hospital, vital signs are typically checked every 4 hours, and you will frequently run into both high and low blood pressures.

Low blood pressure is often much more worrisome, and you may want to call an RRT if the BP is significantly low, especially when the patient is altered or has significant symptoms.

High blood pressure is common, but often is not considered a big deal unless VERY high. In these cases, we want to slowly decrease the blood pressure instead of too quickly.

What is Blood Pressure?

As you probably know, blood pressure is not the pressure of your blood, but rather the pressure within your vascular system.

The vascular system refers to your arteries and veins. When speaking of systemic blood pressure, we are specifically talking about the pressure in the arteries. 

This pressure temporarily increases with each heartbeat, and decreases in-between each heartbeat. 

The pressure in your arteries when your heart beats or contracts is called the systolic blood pressure. Systolic just means during the heartbeat. Systolic blood pressure can never be below the diastolic pressure.

When the heart is not beating, the pressure “rests” back to its normal baseline pressure. This is called the diastolic blood pressure. The diastolic blood pressure should never be 0. 

This pressure is measured in millimeters of mercury (mmHg).

“Normal” Blood Pressure

As we said above, systolic is the pressure during contraction of the heart, and diastolic is the pressure in-between beats. When looking at a blood pressure reading, there are two numbers: a numerator and a denominator. The numerator or top number is the systolic blood pressure. The denominator or the bottom number is the diastolic blood pressure.

Normal systolic blood pressures are between 100 – 120 mmHG. Normal diastolic pressures are between 60-80 mm Hg. Traditionally 120/80 mmHg was considered the “gold standard” for blood pressure, but now its recommended to be at most 120/80 mmHg. 

A "Good" Pressure

A “good pressure” is relative. In the ER, a pressure below 160/90 tends to be considered pretty good and usually won’t require any medications. However, a pressure of 160/90 is considered very high if that is the normal daily blood pressure at home, and should be started on medications.

How to Measure Blood Pressure

We check people’s blood pressures in the hospital, in the outpatient office setting, and pretty much every area of patient care. Nowadays, we have machines that do most of it for us. But machines aren’t perfect, and its an essential nursing skill to know how to check blood pressure.

In general, there are 3 main ways to check someone’s blood pressure:

Manual Blood Pressure

A manual blood pressure is checked using a sphygmomanometer and a stethoscope. The stethoscope if placed over the brachial artery, and the cuff is placed on the patient’s bicep.

The cuff is pumped up to about 160 or 180 (in most people unless BP is very high). Slowly release the cuff pressure while you auscultate the brachial artery. 

Systolic blood pressure is identified by the first Korotkoff clicking sound. The diastolic is noted when you can’t hear anything left.

Palpating BP?

You can palpate the patient’s radial artery when a machine or cuff is pumping up or down. When the radial artery disappears, this is your systolic pressure. There is no way to check diastolic with palpation

Automated Blood Pressure

An automated blood pressure is checked by a machine, often a portable Dinamap or a bedside monitor. These machines essentially perform a manual BP on their own.

They have a sensor which detects tiny oscillations from your pulse. So when the pulse goes away – this is your systolic pressure. When the pulse reappears, this is your diastolic pressure.

A-Line Blood Pressure

Arterial lines are commonly placed in the ICU for strict BP monitoring. This is the most accurate way to check a blood pressure because it is directly measured by a sensor within the arteries, instead of indirectly like with the methods above. This gives you real-time changes in blood pressure.

What’s the deal with the “MAP”?

If you’ve been working for a bit, or in clinicals, you may hear about the term “MAP”. While systolic blood pressure is often considered the most important part of the blood pressure, the actual important number is the MAP. 

The MAP stands for Mean Arterial Pressure. This is the average pressure in the arteries from one cardiac cycle (systolic + diastolic). This is measured by a calculation:

But don’t go busting out your calculators. The bedside monitors should automatically calculate this for you, or possibly your EMR. If you need to calculate it, there are plenty of good online calculators to quickly do it. 

MAP is a great indicator of tissue perfusion. If the MAP stays above 65 mmHg, then this should be enough pressure to provide essential tissue perfusion and prevent anoxic injury (injury from a lack of oxygen to the cells!).

Nurses and Providers in the ICU will care much more about MAP than systolic blood pressure, especially when looking at low blood pressures.


Hypertension, also known as high blood pressure, comes in many different forms. While often thought of as “not a big deal”, it really is the silent killer, and can put a lot of strain on the heart, vasculature, and kidneys.

Overtime, this organ damage becomes more pronounced, placing the patient at risk for heart disease, strokes, kidney failure, and more!

Another reason why it’s termed the silent killer is because it often is asymptomatic – meaning there are no symptoms. But just because there aren’t any symptoms doesn’t mean it isn’t dangerous, especially in the long run. 

In medicine, we use JNC8 guidelines to classify and manage hypertension. 

Blood pressure levels include:

Normal: < 120 / 80 mmHg
Stage 1 HTN: 130 – 140 / 80-89 mmHg
Stage 2 HTN: > 140 / 90 mmHg

Normal Blood Pressure Levels

Hypertension can be chronic or acute. Its also important to know if the patient is having any symptoms such as chest pain, SOB, headache, etc.

3 main types of hypertension that we’ll talk about include:

Primary Hypertension

Primary hypertension, previously referred to as essential hypertension, is a chronic hypertension that has no clear cause, but is thought to involve genetic, dietary, and lifestyle factors. This is what most people are diagnosed with when they have high blood pressure. Risk factors include:

  • Increased age
  • Obesity
  • Family History of HTN
  • Black race
  • High sodium diet
  • Excessive ETOH
  • Sedentary lifestyle

Hypertensive Urgency

Hypertensive urgency is a very high blood pressure > 180/110 mmHg. While there is no evidence of organ damage (i.e. lack of symptoms or lab abnormalities), the patient is at risk for organ damage or strokes to occur.

Hypertensive Emergency

Hypertensive emergency is a very high blood pressure > 180/110 mmHg when there IS evidence of organ damage. The patient should have at least one of the following signs or symptoms:

  • Chest Pain or SOB
  • Pulmonary Edema
  • Severe headache, Seizures, or confusion
  • Elevated Troponin
  • Acute Kidney Injury (elevation in creatinine levels)

Treatment of Hypertension:

Treatment of hypertension is often not aggressive, and is often made by slow gradual changes to outpatient medication regimens.

However, if the patient is symptomatic, blood pressure medications should be given. 

At home blood pressures should be checked, as patients BPs are often higher in emergency and urgent care settings, and “White coat hypertension” is common. 

Some oral medications used to lower BP include:

  • ACE Inhibitors like Lisinopril
  • ARBs like Losartan
  • Calcium channel blockers like Amlodipine
  • Beta-blockers like Labetalol
  • Diuretics like Hydrochlorothiazide
  • Alpha blockers like Clonidine

In hypertensive urgency and when in the hospital, sometimes IV medications may be required including:

  • IV Hydralazine
  • IV Cardizem or Nicardipine
  • IV Labetalol
  • IV Lopressor (metoprolol)

In general, blood pressure should never be lowered too fast. In severe cases, the goal should be to lower the MAP by 10-20% within the first hour, then another 5-15% over the next day. In many cases, this is less than 180/120 in the first hour, and less than 160/110 after 24 hours. 

Lowering the blood pressure too quickly can actually cause ischemic damage in patients who have had elevated blood pressure for a long time. Basically the body becomes used to that high pressure, and while it is dangerous to have high blood pressure in general, lowering it too quickly can cause damage as well.

BP & Symptoms

When it comes to blood pressure (and even heart rates while we’re at it), its always important to ask the patient if they have any symptoms. Ask about any CP, SOB, dizziness, palpitations, headache, numbness/tingling/ etc.


Hypotension is when the blood pressure is too low. Low blood pressure is defined as any pressure less than 100/60 mmHg. However, this is often not considered true hypotension until below 90/50 mmHg.

Patients who are small in stature and thin may have borderline low blood pressures at baseline.

Trend Alert

Worried about the patient’s BP? Trend what their BP has been this hospital visit, as well as previous hospital visits. If their BP is 92/48 but they always run around there and are asymptomatic otherwise – this is reassuring.

Remember if the MAP is less than 65 mmHg, this places the patient at risk for tissue ischemia and organ damage. 

Low blood pressure is often a serious sign, especially in the hospital setting. Common causes of hypotension include:


Septic shock is when there is a severe systemic response to infection. These patients will have persistent hypotension despite adequate fluid resuscitation (30ml/kg bolus). They usually require IV vasopressors, a central line, IV antibiotics, and ICU admission.


Anaphylactic shock is a type of distributive shock that occurs with a severe allergy. Release of inflammatory mediators causes massive systemic vasodilation, swelling, and hypotension. This is treated with IV steroids and antihistamines, +/- epinephrine.


When the patient loses enough blood, they will become hypotensive. These patients need STAT blood, usually O negative blood that hasn’t been crossmatched. 

Cardiogenic Shock

Cardiogenic shock occurs when the heart can’t keep up with the body’s demand. This can occur in severe CHF or bradyarrhythmias.

Drugs / Medications

Maintenance medications given for blood pressure can cause low BP, especially if taken in wrong doses or if they become toxic. Some other medications have hypotension as a possible side effect such as amiodarone. 

Adrenal insufficiency

Patients with a history of adrenal insufficiency will often require stress-dosed steroids to maintain their blood pressure. 

Severe dehydration

Dehydration needs to be severe before the patient becomes hypotensive. This can occur in those with DKA or diabetes insipidus, or really anything that causes dehydration.

Treatment of Hypotension:

Treatment of hypotension will involve treating the underlying cause, but generally involves 2 steps:

  • IV Fluid boluses: to increase the volume of the blood
  • Vasopressors: To cause constriction of the blood vessels

If fluid boluses do not improve blood pressure, or if the BP drops back again once its done, then the patient may need vasopressors in the ICU.

Depending on the cause, the underlying cause should be addressed, including:

  • Blood for blood loss
  • Antibiotics and fluids for sepsis
  • Steroids for adrenal crisis
  • Steroids & Antihistamines for Anaphylaxis

Wrapping Up

You are going to run into TONS of patients who either have high blood pressure, or low blood pressure. Managing vital signs is a huge part of our jobs as nurses and doctors, and its so important to understand how to manage blood pressure!

Remember these important concepts when it comes to blood pressure:

Double Check the Pressure

Double check your blood pressures. If it doesn’t seem right – check a manual BP. The provider may ask you to do this anyway.

Always ask about Symptoms

If your patients BP is high or low, ask them if they have any symptoms. Focus on any headache, chest pain, shortness of breath, dizziness, lightheadedness, palpitations, syncope, etc.

Trend the Pressures

Remember high blood pressure shouldn’t be corrected too quickly. Look at previous trends. Don’t freak out about blood pressures that are high unless the patient has symptoms. Worry more about low blood pressures!


Basil, J., & Bloch, M. J. (2022). Overview of hypertension in adults. In T. W. Post (Ed.), Uptodate.

Calder, S. A. (2012). Shock. In B. B. Hammond & P. G. Zimmerman (Eds.), Sheey’s manual of emergency care (7th ed., pp. 213-221). Elsevier.

Gaieski, D. F., & Mikkelsen, M. E. (2022). Evaluation of and initial approach to the adult patient with undifferentiated hypotension and shock. In T. W. Post (Ed.), Uptodate

Roe, D. M. (2015). Cardiac emergencies. In B. A. Tscheschlog & A. Jauch (Eds.), Emergency nursing made incredibly easy! (2nd ed., pp. 97-197). Lippincott Williams & Wilkins.

William Kelly, MSN, FNP-C

Will is a Nurse Practitioner who is the founder and author of Health and Willness, an online educational platform to build clinical knowledge and skills of nurses and nurse practitioners!


How to Become a Registered Nurse (RN)

How to Become a Registered Nurse (RN)

William J. Kelly, MSN, FNP-C
William J. Kelly, MSN, FNP-C

Author | Nurse Practitioner


How to become an Registered Nurse (RN) is frequently asked and it is a great career to go into! It can be a lot of hard work but it is worth it in the end. I personally was an RN for 4 years and currently I work with them daily as an ER Nurse Practitioner – so I think I can give some insight into becoming an RN.

There are multiple different pathways to become an RN, but I’m going to outline the most common way, as well as the less common pathways.

If you prefer to watch instead of read, check out the video below!

What is a Registered Nurse?

A Registered nurse is a nurse who has been trained to take care of patients in and out of the hospital.

They provide hands-on care to their patients, carrying out orders and advocating for their patients.

Within the hospital, an RNs job includes:

  • Patient assessment
  • Medication and Treatment administration
  • Communication with Providers and other nurses
  • Patient Education and Discharges


When deciding on how to become a Registered Nurse, one of the first things you will need to figure out is which type of program you want to attend.

There are programs that offer various different degrees and various different lengths.

There is no “one size fits all”, and that will become apparent when researching how to become a Registered Nurse.


In order to gain entry into any RN program, you will need your high-school degree or its equivalent (GED).

This is pretty standard for many professions, and most people already inherently understanding this step.

RN programs want to know that you are academically capable in a classroom setting.

However, there are specific pre-requisites and application requirements or recommendations that nursing schools are going to want to see on your transcripts from high school.


Nursing programs want to see certain classes that you have taken in high school in order to be considered for their program.

These pre-requisites classes include:

  • Basic and Advanced Math
  • Science courses (Biology, Chemistry, and Physics are all great ones)
  • English

Not every program is going to require every single one of these, as many can be flexible.

Each program will vary, but check out some programs that you are interested online, and look for their “admission” page, which may give some insight into specific recommendations for high school students.

Many programs require a minimum GPA as well as a certain SAT score – this will depend on the university and program.

The better your GPA and SAT scores, the more competitive your application will be.


In order to be a serious candidate, focus on doing your best in high school and obtaining the best GPA you can.

Additionally, programs like to see that your involved involvement in extra-curricular activities.

Some of these extra-curricular activities include:

  • Sports & Cheer
  • Music & Theater
  • Student Council
  • Journalism
  • Various other Clubs

Taking Advanced Placement (AP) science classes will make you stand out.

These look great to many nursing programs and can potentially offer you university credit, which can make your nursing program a little more manageable.

An additional application boost is real-life work experience in a related field.

Working as a CNA, EMT, Medical scribe, or personal caregiver are all great options that look great to nursing programs!



Nurses can become a registered nurse sooner by obtaining an associate’s degree instead of a bachelor’s degree.

An ADN aims to give students the basic technical and academic knowledge to go into employment.

For nurses, this includes core science classes, as well as your basic “how to be a nurse” classes.

This also includes approximately 700 hours of clinicals within the hospital – learning how to be a bedside nurse.

Typical classes for ADN include:

  • Basic Nursing Fundamentals and Skills
  • Anatomy and Physiology
  • Nutrition
  • Emergency Care
  • Pediatric Nursing
  • Obstetric Nursing
  • Med-Surg Nursing.

Most ADN degrees will take about 2 years to finish.

This is about HALF of how long a BSN takes. This lets the nurses enter the workforce sooner.

If they still desire a BSN or if their facility requires it, an RN-to-BSN bridge program can be taken, usually all online, which can be completed in an additional 1-2 years of education.

Obtaining your BSN this way gives you bedside experience quicker, and helps you make money sooner.

If you want to go into administration or advance your nursing education, obtaining a BSN is required.

ADN vs BSN | ADN Is a 2 year degree that will grant you an associates degree in nursing, and BSN is a 4 year degree that will give you a bachelor of science in nursing. BSN focuses more on research, evidence-based practice, leadership, and ethics, whereas ADN focuses on essential nursing knowledge and skills


Obtaining your Bachelor of Science in Nursing (BSN) is recommended and often needed to do anything “beyond” bedside nursing.

This traditional 4-year degree is what many future nurses choose to attend straight out of high school.

This gives them the “traditional college experience”, but also offers them an excellent nursing education.

Students will learn how to assess their patients, how to assess their patients, and how best to help manage their care.

This involves every aspect of patient care including:

  • Personal care
  • Medication administration
  • Communication with physicians or ancillary staff
  • Delegation
  • and more!

Additionally, they are required to attend clinical as well. Clinicals are learning opportunities within the clinical setting, where student nurses can shadow and assist registered nurses in accomplishing their nursing tasks.

The intent is to obtain first-hand experience and directly learn how to be a nurse. By graduation, most programs require somewhere between 800-1000 hours of clinical.

The “BSN” education for nurses involves all of the classes that the ADN programs offer, in addition to:

  • English
  • Statistics
  • Research
  • Evidence-based practice
  • Leadership
  • Ethics
  • Community Health

Obtaining your BSN is definitely a great option and will set you up for future endeavors and professional advancement.


So what’s the actual difference then between an ADN-prepared and a BSN-prepared RN?

Well even though you complete your program quicker and can start working sooner as an ADN, you are less-educated.

Many facilities require BSN education, and some will hire you but offer you money to help you pay for the BSN portion, contractually requiring you to complete it.

Many magnet hospitals will prefer to hire BSN-prepared nurses.

Some facilities will pay their RNs the same regardless, but many offer incentives for advanced education as well as certifications. So you might make a few more dollars per hour as a BSN vs ADN.

Additionally, you can earn a higher hourly rate by obtaining specialty certifications like Certified Emergency Nurse (CEN) or Critical Care Registered Nurse (CCRN), if that is the specialty that you work in.

Overall, there is a large push for BSN-prepared nurses, and there is some evidence to back this up, with improved patient outcomes correlated with increased nursing education.


I’m not going to elaborate much on this as it is largely being phased out, but Diploma RN programs once used to be a very common way of obtaining your nursing education.

These programs were often run by hospitals that offered a lot of hands-on education and “learn-on-the-job” experiences.

This has largely been replaced with degree-offering programs from universities and colleges.


Once you have all the required prerequisites listed above and know which program(s) you want to attend, you can start applying to programs!

The difficulty in the admittance is going to depend on your application as well as how competitive the RN program is.

Some nursing programs are very difficult to get into!

If unable to immediately get it, some students choose to attend the university of choice as an “undeclared” major, take important classes within the RN curriculum, and then hope to be accepted into the program as a transfer once they’ve proven to do well.

Learn how to become a registered nurse RN by first completing high school, then choosing a nursing program ADN vs BSN, finishing a program including clinical hours, passing the NCLEX-RN, and then applying for RN state licensure

4. Graduate and Pass the NCLEX-RN

Once you finish your RN program, you have to take a competency exam to prove your knowledge as a Registered Nurse.

This test is called the NCLEX-RN, and you will spend a large portion of your education preparing for this test.

Each state board of nursing uses this test as the basis for whether or not you deserve your RN license within their state.

Once you pass (and hopefully in 75 questions), you will have been deemed “worthy” of the RN title after your name, once your state license has gone through.

Once you apply for state licensure by exam, you can apply for state licensure by endorsement for other states.

Or better yet, if your state is part of a compact RN license state, then your license is good for all of those states!


Once you’re licensed, you can get a job as a registered nurse and finally start using that knowledge you’ve obtained to positively impact your patient’s lives as well as your bank account!

Finding a nursing job can sometimes be tough, but if you’re willing to be flexible – there are so many nursing opportunities out there!

Related Articles:


I wanted to talk a little bit about some alternative options when trying to decide how to become a registered nurse.

As always, one size does not fit all and some of these other options may be the perfect fit for you!

1. Accelerated “Direct-Entry” Programs

If you already hold a Bachelor’s degree in another program (i.e. business, math education, Biology), there are programs designed to accelerate your education into becoming an RN.

This is partly due to many of the prerequisites being completed (Gen eds), but also as the programs are intensive and designed for students who just want to “catch up” and become nurses ASAP.

These programs often have science pre-requisites, are very involved, require maximum effort, rarely take “breaks”, and can be completed in as little as 16 months!

At graduation, each participant is awarded a BSN.

2. LPN to RN programs

If you are already a Licensed Practical Nurse (LPN), attending an LPN-to-RN bridge program is an excellent choice to become an RN.

There are programs that award an ADN, as well as programs that award a BSN.

As above, choose which option is best for you.

LPN-to-ADN programs will be able to be completed quicker in 1-2 years, and LPN-to-BSN programs in 2-4 years.

3. Foreign Educated to RN in US

If you obtained your RN education from an accredited RN program in a different country, you can apply for state licensure within the US.

This will require:

  • At least 2 years of RN experience
  • A Foreign-Educated Nurse refresher course
  • English proficiency tests

For more information, check out this article.

So there you have it. If you are wondering how to become a registered nurse, hopefully, this article gave you some insight.

How did you become an RN, and would you recommend anything different? Let us know in the comments below!


Learn how to become a registered nurse RN by first completing high school, then choosing a nursing program ADN vs BSN, finishing a program including clinical hours, passing the NCLEX-RN, and then applying for RN state licensure

Oxygen Delivery Devices and Flow Rates

Oxygen Delivery Devices and Flow Rates


William J. Kelly, MSN, FNP-C
William J. Kelly, MSN, FNP-C

Author | Nurse Practitioner

Oxygen Delivery Devices and Flow Rates are important concepts to understand as a nurse. Oxygen is a life-saving therapy that nurses and respiratory therapists administer every day in the hospital.

Whether your patient is on chronic oxygen, or whether they are in acute respiratory failure, your patients will commonly have oxygen ordered and it will be up to you as the nurse to administer it. 

Knowing the oxygen delivery devices and flow rates will tremendously help you take care of your patients who requires oxygen.

Oxygen delivery devices and flow rates FB

The Role of Oxygen

Oxygen is used every day in and out of the hospital. In order to understand oxygen delivery devices and flow rates, we need to first understand a few basic principles and definitions.

Oxygen is the most important gas in our atmosphere that allows for humans and animals to live. Our cells use oxygen to create energy (Kreb’s cycle anyone?). Our ability to create energy without oxygen is very limited.

Without oxygen, our cells will die within minutes.

Oxygen occurs naturally in our atmosphere, at a concentration of 21%. Another term for oxygen concentration is FIO2, or fraction of inspired oxygen.

When we breathe in air, the air (including oxygen) enters into our lungs and makes contact with all of the alveoli. Alveoli are small sac-like structures within the lungs.

The oxygen diffuses across these alveoli into the bloodstream, where it attaches to hemoglobin on our red blood cells. Our blood carries this oxygen throughout the body where it is absorbed by the tissue to give life and energy to our cells.

A healthy patient has a respiratory rate of 12-20 respirations per minute (rpm). Lower than 12 is usually from medications like opioids or benzos, and higher is usually from anxiety, asthma, COPD, CHF, a PE, pneumonia, or some other type of respiratory failure.

The tidal volume is the amount of air breathed into the lungs with each breath. The tidal volume will depend on the patient’s physical size of their lungs and their respiratory effort, but is generally around 400-500ml in a healthy adult.

The FIO2 or the fraction of inspired oxygen is the percentage or concentration of oxygen that a person inhales. Remember room air is always at 21% FIO2 on earth.

Oxygen Delivery Devices and Flow Rates

There are different oxygen delivery devices and flow rates to know, with each device allowing for certain flow rates of oxygen (L/min), as well as different concentrations of oxygen (FIO2).

Blow-by Oxygen

Blow-by oxygen is just that – it’s oxygen that blows by. This does not not apply oxygen directly, but rather indirectly by “blowing” on the patient’s face.

This is usually only used in infants and young toddlers who become agitated when masks or tubing is applied.

Less than 30% FIO2 can be provided with this, which is not much greater than room air of 21%.

If used, the oxygen rate should be at least 10 L/min through a simple mask or even a tubing sticking through a styrofoam cup, which infants and toddlers may be less scared of.

Nasal Cannula

Nasal cannula is tubing that runs from the oxygen source to the patient’s bilateral nares or nostrils.

This is the most common use of oxygen within the hospital, especially for non-critical patients and those who need chronic oxygen delivery like with COPD.

Nasal Cannula is typically started at 2L/min and then titrated upwards to as high as 6L/min, although 2-4L/min is ideal. This delivers 25-40% FIO2, depending upon their respiratory rate, tidal volume, and amount of mouth breathing.

The nasal cannula is good for most patient needs with lower levels of oxygen requirements.

Nasal cannula can be very irritating and cause dry nares at rates >2L/min, so the oxygen should be heated and humidified if possible at higher flow rates.

Simple Face Mask

Simple face masks are a mask with tubing that is hooked up directly to an oxygen source. This is similar to Nasal Cannula, except it is delivered in a mask format over the mouth and the nose, instead of just the nose.

Simple face masks allow for flow rates between 6-10L/min, with an FIO2 of 35-50%.

Simple face masks tend to be a temporary solution, used when titrating your oxygen delivery devices and flow rates. 


Ventimask or a Venturi mask is a face mask that is connected to corrugated tubing with a venturi valve on the end.

This piece connects to the oxygen tubing, which mixes oxygen with room air to provide a consistent high flow of oxygen even with irregular respiratory rates or tidal volumes.

Depending on the oxygen flow rate, there are different colored venturi pieces that are used, with FIO2 of 24-60% FIO2 depending on which venturi valve is used. Levels >40% are generally not used and likely don’t offer more benefit.

The oxygen flow rate will be indicated on the specific venturi valve used, but generally is from 3-10L/min.

Some Ventimasks come in an all-in-one rotational setup, where the FIO2 can be adjusted on a single venturi valve.

Ventimasks are usually used with COPD patients when they require high levels of oxygen, but there is concern for CO2 retention. It can also be helpful for asthma exacerbations and general respiratory distress.

This is typically not used long-term.


A Non-rebreather is typically what is initially used when the patient is requiring a high flow of oxygen and nasal cannula’s are not cutting it.

A non-rebreather provides the highest concentration of oxygen that can be provided to a patient who is breathing on their own, up to 95% FIO2, without any additional machines.

However, this is NOT a long-term solution, and unless they can be titrated down, patients will need to be transitioned to a BIPAP, HFNC, or intubation, unless they can be titrated down.

In a non-rebreather, there is a reservoir bag attached to the mask, with a one-way valve separating the two. This prevents exhaled CO2 from entering the reservoir, and only allows oxygen.

There are holes or “exhalation ports” in the sides of the mask that allow expired are out also do not allow room air back in (usually only one of these is “blocked” to prevent suffocation if the oxygen turns off).

Oxygen flow rates of 10-15L/min can deliver FIO2 of up to 95% in these individuals. However, there is a small amount of room air which “gets in” the system, so the FIO2 is invariably lower, more like 80-90%.

Remember over-oxygenation can also be dangerous termed “oxygen toxicity”. This can cause vasoconstriction, worsen outcomes, and even cause seizures.

This means you want to keep the patient’s SPO2 at 94-99%, as a pulse ox does not measure above 100%.

If a patient is still struggling to breathe with SPO2 of 88-94% or lower on a NRB, then they probably need intubated.

High-Flow Nasal Cannula

High-Flow Nasal Cannula (HFNC) is a newer method of delivering a high flow and FIO2 of oxygen in patients who have higher oxygen requirements. COVID patients tend to do well on these devices, but it can be used for all sorts of respiratory distress.

High-flow Nasal cannula consists of a specific machine and tubing used to deliver a very high flow of oxygen that is heated and humidified.

HFNC can be delivered from 8-60L/min (30-60 L/min in adults), and an FIO2 of 100%.

HFNC is more comfortable and studies have shown that using HFNC may be a better alternative than using a face mask.

HFNC also adds PEEP-like pressure equivalent to about 3-4 cm H2O, similar to a CPAP, helping to keep the alveoli open and increase ventilation (gas exchange).

It is also an alternative to BIPAP other than those patients who are hypercarbic (high CO2 levels like in COPD).

Knowing the difference between the oxygen delivery devices and flow rates, HFNC is not a good option for those who are CO2 retainers for very long .


CPAP or Continuous Positive Airway Pressure is a method of non-invasive ventilation. This helps open up the alveoli allowing for better gas exchange.

This can be useful in acute pulmonary edema like in CHF, because it reduces intrathoracic pressure and can reduce preload and increase cardiac output, as well as decrease alveolar congestion.

It is also used for obstructive sleep apnea (OSA) to keep the airway open.

Oxygen is not always added (especially if the patient is just using it for OSA). The pressure is set at 5-20 cm H2O, usually beginning at 5-8 cm H2O.

Increased pressures will increase intrathoracic pressures.

Oxygen is added to keep SPO2 >90%.


BIPAP or Bilevel Positive Airway Pressure is the “better” version of CPAP. This can often be used as an alternative to intubation, and is great for hypercapnic respiratory failure (think COPD).

This uses a higher pressure during inspiration and a lower pressure during expiration.

BIPAP uses 3 settings:

  • Rate: The respiratory rate is usually set to a backup or spontaneous rate, as these patients are awake and breathing spontaneously. This is usually 8-12 rpm. Most patients on a BIPAP will be breathing much faster than this.
  • IPAP: The inspiratory positive airway pressure is how much pressure is given during inspiration. This is anywhere from 5-30 cm H2O, but usually started at 8-12 cm H2O. A higher level will increase tidal volume.
  • EPAP: The expiratory positive airway pressure is the pressure during expiration, which is typically 3-5 cm H2O.

Oxygen delivery is then used as well to ensure SPO2 >90%. FIO2 is started at 100% and titrated down.

Clinical Note: Settings are usually given as IPAP/EPAP, Rate, and FIO2. This means you would relay the settings as 10/5, backup rate of 10, and an FIO2 of 30%. The RT should tell you the settings and they should be the ones to titrate the FIO2.

This is used for Acute COPD exacerbations, and acute respiratory failures like in CHF or ARDS. It can work great for reducing CO2 retention in hypercarbia subsequent and respiratory acidosis.

This is not good for those who are nauseous or have thick secretions, as this may be a risk for aspiration. This can be dangerous for those who are altered for the same reason, although is sometimes still used.


Mechanical Ventilation is the best way of controlling a patient’s oxygenation (oxygen delivery) and ventilation (gas exchange).

Mechanical ventilation is used as a last resort when a patient is in severe respiratory distress and cannot tolerate non-invasive ventilation.

These patients are in respiratory failure and may be altered, cannot protect their airways, are throwing up, or just continue to be hypoxic despite alternative oxygenation.

To be put on a ventilator, a patient will need intubated, likely sedated, and hooked up to a ventilator.

Ventilators have various settings which control the respiratory rate, the IPAP, the EPAP, the inspiratory flow rate, and the FIO2%.

If ventilation can be avoided, it should be. Some patients are difficult to wean off the vent (like in severe COPD or ARDS).

And that is an overview of oxygen delivery devices and flow rates. Hopefully you have a solid understanding of each device and when it is appropriate to use each one.


Hyzy, R. C., & McSparron, J. I. (2021). Noninvasive ventilation in adults with acute respiratory failure: Practical aspects of initiation. In T. W. Post (Ed.), UpToDate.

ICU Advantage. (2020, January 13). CPAP vs BiPAP – Non-Invasive Ventilation EXPLAINED [Video]. YouTube.

Nagler, J. (2021). Continuous oxygen delivery systems for the acute care of infants, children, and adults. In T. W. Post (Ed.), UpToDate.

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