What is the typical flow rate during inhalation?

I was wondering if anybody here could point me to any reference or provide any data for the typical flow rate during inhalation. I know this will depend on a number of factors like a person's build, lung capacity, etc. I have seen flow curves, but have not seen any with a scale for the flow or time axis. Thank you!

Flow rate would change, person by person, minute to minute, it's like asking how many times a person breaths in a day. No standard, unuseful info.

How are you going to find out what's normal? More important how are you going to change the flow rate.

The only way would be to be in a Iron Lung, have your normal breathing suppressed, then your flow rate would be what it was set to provide. Jim

Sure, as I acknowledged, the flow rates will vary. I am looking for ball parks. We know most people will be between 4' and 7' tall, and not 40' I have the vaguest idea what the flow rate is. Teach me.

Too many variables, unless you are on a vent. Encore Pro doesn't mention it at all.

It would depend on your breath per minute rate, (variable)(Brain Controlled) . Your LPM, for each breath, (another Variable)(Brain Controlled)

The only way I can see a answer, is do away with the brain control, and make flow rate the same each time. (A lron Lung or Vent)

The have clocked a sneeze at 140 MPH, I think at times I can beat that. I'm one that goes into sneezing fits at times. Jim

You could find out the settings for a Iron Lung, that should be the level required to sustain life. That sounds like a magic number to me! Jim

Iron Lung:
Since Drinker's invention, a class of breathing machines called ventilators and respirators has been developed. A modern ventilator consistsof an electrical pump connected to an air supply, a humidifier which adds moisture to the air, and a tube which is inserted into the patient's nose or mouth. Ventilators, unlike the iron lung, use positive air pressure from the pump to force air into the lungs and the patient exhales the air naturally. Toadjust the oxygen-carbon dioxide ratio supplied by the ventilator, blood samples from the patient are analyzed to determine the metabolic rate. The volumeof air required and the number of times per minute the patient needs to breathe in order to maintain the desired metabolic rate, is also calculated, andpositive air pressure administers the correct mix and volume into the lungs,which deflate passively. Today's sophisticated hospital respiratory care units may utilize up to 15 different kinds of respirators. Ventilators assist patients unable to breathe for themselves, who suffer from degenerative muscle disease, or burns to the nose and throat. Some patients may be connected to a ventilator for months at a time, in which case a breathing tube is surgically inserted directly into the trachea (windpipe). Today, in such placesas Stanford University Hospital in California, the iron lung of the 1950s ismaking a comeback due to it's non-invasive, negative air pressure which eliminates the possibility of infections or scarring prevalent with respirators which require a tracheotomy. The iron lung can also be used at home to help a patient rest respiratory muscles either during the day or night.

Miniature ventilators are also used to help premature babies breathe and provide temporary breathing assistance to patients undergoing surgery requiring anesthesia. At University Hospital in Stony Brook, New York, mini-iron lungs are used for some patients. Nicknamed turtles because of their green color and shell-like shape, these miniature iron lungs can be strapped onto a patient's chest. For treating sleep apnea, a sleep disorder in which breath becomes obstructed, a small ventilator about the size of a vanitycase is connected to a tiny mask placed over the nose. Intermittent positiveair pressure is delivered through the nostrils and the timing can be preset to correspond with the patient's natural breathing rate.

From our friend Google.

http://www.faqs.org/health/topics/91/Ir ... ators.html

Tidal volume (Vt) = 500 mL measured The amount of air breathed in or out during normal respiration. The volume of air an individual is normally breathing in and out.

This is, of course, a ballpark figure and YMMV. Google Tidal volume and you'll get lots of hits with information about variation.

abysmillard wrote:Tidal volume (Vt) = 500 mL measured The amount of air breathed in or out during normal respiration. The volume of air an individual is normally breathing in and out.

This is, of course, a ballpark figure and YMMV. Google Tidal volume and you'll get lots of hits with information about variation.

That's a volume ... not a flow rate.

But! if that is a normal volume of air ... to determine rate you then just need to find out what the average number of breathe per some unit of time is and you can calculate flow rate.

I think if you have a PFT you probably can get answers on your own volume and perhaps they can determine your max rate of flow

Don't you need to know how long you are breathing in (versus out versus not bothering to use any of those muscles) to get a rate if you have the volume you breathe in?

Even with a volume and an inhalation time you only get an average flow not an instantaneous one and I assume OP wanted the max rate

That number 500mL is good enough for me. I only wanted an approx volume, I can figure out an approximate flow rare. Thanks.

feeling_better,

If your tidal volume is 500 ml and inspiratory time is 1 second, your inspiratory flow rate would be 30 liters/minute. On ventilators, the flow rate is typically set 40-60 liters/minute. Hope that helps.

Okay, I have COPD so these figures most likely would NOT be the same for someone w/healthy lungs but over the last 30 days on my bi-level:

Minute Ventilation (volume of air in or out w/in 60 seconds)
Median: 5.2 L/M, 95th Percentile: 7.5 L/M, Maximum: 11.2

Respiratory Rate (breaths per minute)
Median: 17, 95th Percentile 20, Maximum 25

Tidal Volume (air inspired or expired in one breath)
Median: 300 mL, 95th Percentile: 460 mL, Maximum: 740 mL

Just last week I had the second of two spirometries done 3 months apart but didn't dig them out to post those results as I'm not sure which figures would be pertinent.