Disclosure OXYGEN BASICS. Objec ves 8/15/14 BUT IN REALITY IT WILL SUFFICE IF YOU TAKE HOME 3 KEY MESSAGES

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1 Disclosure OXYGEN BASICS UTHSCSA No other financial or commercial affiliaons Jesus R. Guajardo, MD, MHPE, PhD Objecves This is a entry level lecture about some key points about the clinical use of oxygen Appropriate for MS, residents, RTs, and health care personnel who provide oxygen to end of this talk, the listener should be able to Define Respiraon Describe the transport of O2 in the human body List several variables that may affect the amount of oxygen available for respiraon To get a general understanding of the variables, not to learn all the formulas and lile details (that will happen during the pulmo rotaon) BUT IN REALITY IT WILL SUFFICE IF YOU TAKE HOME 3 KEY MESSAGES FOCUSING SCENARIOS FIRST ONE 1

2 Normal ABG ph: ( ) pco2: 40 mmhg (35-45 mmhg) po2: 100 mmhg ( mmhg) HCO3: 24 meq/l (21-28 meq/l) B.E. - 2 to +2 meq/l Now Imagine You arrive to the intensive care unit and have a paent with narcoc overdose recently placed on a venlator with good breaths and you are giving FiO2 100% O2, sats are at 100% ABG is ph: 7.40 CO2: 40 mmhg PaO2: 250 mmhg HCO3: 26 R these values OK? Make a Wish SECOND SCENARIO You have a paent with a bad lung condion (CF, fibrosis, cancer, etc) and the paent is on the ward on 4 lpm O2 NC and 90%. Stable for the last few weeks. Final wish is go to Hawaii and bite the dust there. Expected demise in 2-3 months. Has plane ckets to Hawaii for next week (SAàHouàIsland). Make a Wish Any recommendaons for the trip? a. Bring a souvenir? b. Call the airline to make sure she takes a commercial flight- approved oxygen device? c. Galveston not good enough? d. Exchange the plane ckets for cruise ship ckets? THIRD SCENARIO 2

JOY RIDE JOY RIDE You and your friends are going for a

For this, you prepare with an oxygen tank and a non-

case, a parachute) Is this enough for your oxygen

Oxygen Tubing FOURTH SCENARIO You have a paent at home

He is takes 3 lpm per NC He likes to piggyback the

3 JOY RIDE JOY RIDE You and your friends are going for a balloon ride. You want to go as high as you can. For this, you prepare with an oxygen tank and a non- rebreather mask (also with good clothes and just in case, a parachute) Is this enough for your oxygen requirements? Oxygen Tubing FOURTH SCENARIO You have a paent at home with a large oxygen tank. He is takes 3 lpm per NC He likes to piggyback the oxygen tubing, so he can walk all around the house without dragging the tank. He has 300 feet of tubing Is that bad?? Know this Guy? FIFTH SCENARIO 3

4 Oxygen We all seen these hook ups for oxygen. When you turn the knob What comes out: LAST SCENARIO a. 100 % O2 at the dialed lpm? b. 21% O2 that needs to go through a concentrator? c. O2 % depends on the device aached at the end of hose d. O2 % depends on the number dialed e. Compressed air that needs to be brought up to 100% O2 Areas to be Reviewed LETS START WITH BASIC CONCEPTS Atmosphere The Hook- ups No definite boundary with outer space Most of it (75%) contained on the first miles For praccal purposes, all over the world: 21% O2 & 79% N2. So, room air (RA) = 21% O2. If one is breathing RA, then FiO2 = 21%. 4

The Hook- ups What comes out when you turn open the knob of the green hook up (O2)?

being given? Easy answer: As many lpm as the valve indicates And for these devices?

The answer requires some math, a table or chart, experience, or amazing guessing. Let s take a very quick view.

NC 2lpm=2kcc60s =2k/60à ~35cc/sec TV 500 cc 21%O2=105cc 79%N2=395cc 105cc O2TV + 35cc O2NC 140 cc of O2 Out of

28 Assumpons Simple Chart for Adults when using NC: O2 NC @ 2 lpm Pt wt = 2 kg TV = 15 cc RR = 40 I:E 1:2 0.

5 The Hook- ups What comes out when you turn open the knob of the green hook up (O2)? 100% O2 at the number of lpm indicated by the lile ball Clinical Applicaon Easy Queson: How much oxygen is being given? Easy answer: As many lpm as the valve indicates And for these devices? the % dialed the # lpm dialed Not as easy Queson: What s the FiO2 for these paents? The answer requires some math, a table or chart, experience, or amazing guessing. Let s take a very quick view. Pt s Wt % O2 Flow O2 2 lpm Pt wt = 70 kg TV = 500 cc RR = 12 I:E 1:2 1 s ins, 2 s exh 1 s 500 cc inhaled NC 2lpm=2kcc60s =2k/60à ~35cc/sec TV 500 cc 21%O2=105cc 79%N2=395cc 105cc O2TV + 35cc O2NC 140 cc of O2 Out of 500 = 28% ~ 0.28 Assumpons Simple Chart for Adults when using NC: O2 2 lpm Pt wt = 2 kg TV = 15 cc RR = 40 I:E 1:2 0.5 s ins, 1 s exh 0.5 s 15cc inhaled NC 2lpm=2kcc60s =2k/60à ~35cc/sec (17.5 per 0.5 sec) TV 15 cc 21%O2=3.15cc 79%N2=11.85cc 3.15cc O2TV cc O2NC 21 cc of O2 Out of 15 = high % ~ High Flow Lpm Charts are a lile more complex for Infants Oxygen Devices COMMON OXYGEN DEVICES 5

$Short Summary O2 concentraon in the atmosphere is 21% O2 at room air (RA) is 21% FiO2 is the inspired fracon of O2 in the TV @ RA, FiO2 = RA = 21% For adults and as a general rule, NC increases 3%$ %, RA, FiO2, and oxygen delivery devices Now lets review other terms: atmospheric pressure, PAO2, PaO2, and hemoglobin dissociaon curve Atmospheric Pressure Commercial Plane Traveling Atmospheric

%, RA, FiO2, and oxygen delivery devices Now lets review other terms: atmospheric pressure, PAO2, PaO2, and hemoglobin dissociaon curve Atmospheric Pressure Commercial Plane Traveling Atmospheric

6 Short Summary O2 concentraon in the atmosphere is 21% O2 at room air (RA) is 21% FiO2 is the inspired fracon of O2 in the RA, FiO2 = RA = 21% For adults and as a general rule, NC increases 3% FiO2 for each lpm, but, for the pediatric populaon this is not the case There are many oxygen delivery devices; keep in mind the characteriscs of the most common ones O2 Transport We have reviewed O2 %, RA, FiO2, and oxygen delivery devices Now lets review other terms: atmospheric pressure, PAO2, PaO2, and hemoglobin dissociaon curve Atmospheric Pressure Commercial Plane Traveling Atmospheric Pressure Atmospheric pressure hp://usatoday30.usatoday.com/news/naon/ oxygen.htm 1 mol of a gas occupy 22.4 liters at STP (Standard Temp = 0 C Pressure: 760 mmhg) Oxygen atomic weight: ~16. O2=32 Daltons 1 mol of O2 = 32 gm. 1 kg = 700 liters gm per liter of O2 (at 760 and O⁰ C) Ideal gas equaon by Emile Clapeyron (1834) combining Boyle s and Charles laws V=nRT/P How do we use these values clinically? At body temperature ( = 311 K), one liter of O2 will have Alt (m) kpa mmhg Atm Moles Gms Rel% Sea Level Denver Cabin Pressure Mexico City MachuPicchu Mt Olympus Mt Everest Mars (Planet) Humidificaon H20 50 mmhg Alveolar Equaon Lungs [O2] Atm Sea level ~ 760 mmhg Room Air 21% 02 (160 mmhg) 79% Nitrogen (600 mmhg) 760 mmhg at mouth minus 50 when humidified mes the FiO2 à 150 Minus CO2 à 100 mmhg How much O2 in the alveoli? PAO2= (FiO2 * (AtmPress H20) ) - PCO2/RQ PAO2= 100 mmhg (80-100) or ~13% (down from 21%) CO2 coming out at mmhg PA The alveolar gas equaon helps esmate the PAO2 and from there we can esmate the arterial pressure as it should be within 5-10 mmhg at RA 100% FiO2)? Formula: (FiO2 * (AtmPress H20) ) minus PCO2/RQ Normal: ( 0.21 * ( ) ) minus 40 /0.8 à ~ 100 mmhg Then the PaO2 should be mmhg at sea level (760 mmhg) And how is this related to hemoglobin saturaon? Pa 6

Sea Level = ~ 100 mmhg (0.21*(763-50)) (40/.08) Denver = ~ 72 mmhg (0.21*(630-50)) (40/.08) Mt Everest < 30 mmhg (0.21*(253-50)) (40/.08) On 100% FiO2 here in SA > 550 mmhg (1.00*(764-50)) (40/.

4 lpm is 4000/60 is ~ 67 cc/sec. 500cc is 105 cc of O2 (21%) +395 ccn2. 105cc (21%) + 67cc (NC @ 4 lpm)=172 172 cc O2 of 500 is around 35% O2. FiO2=0.

8 à ~ 200 mmhg Assumpon from the Alveolar Equaon PA= 0.35 (760-50) 40/0.

7 Sea Level = ~ 100 mmhg (0.21*(763-50)) (40/.08) Denver = ~ 72 mmhg (0.21*(630-50)) (40/.08) Mt Everest < 30 mmhg (0.21*(253-50)) (40/.08) On 100% FiO2 here in SA > 550 mmhg (1.00*(764-50)) (40/.08) Alveolar Pressures Keep in mind 30 mmhgà 50% & 60 mmhgà90% Worked Case Make a Wish: Hawaii Scenario: Pt on 4 lpm O2 NC with 90% sats Assumpons: TV 500 cc in 1 s Insp. FiO2? 4 lpm is 4000/60 is ~ 67 cc/sec. 500cc is 105 cc of O2 (21%) +395 ccn2. 105cc (21%) + 67cc 4 lpm)= cc O2 of 500 is around 35% O2. FiO2=0.35 Alveolar Equaon PA= [FiO2(AP- H2O)] (CO2/RQ) PA= 0.35 (760-50) 40/0.8 à ~ 200 mmhg Assumpon from the Alveolar Equaon PA= 0.35 (760-50) 40/0.8 à ~ 200 mmhg Assumpon from the Hbg dissociaon 90% there should be ~ 60 mmhg PaO2 There seems to be an A- a gradient of 140 mmhg (200-60). Therefore we need to keep the same PA while the atmospheric pressure is reduced in the plane (lets assume 550 (to be safe, as 565 mmhg is the minimum by FAA). Alveolar Equaon: PA= [FiO2(AP- H2O)] (CO2/RQ) 200= FiO2 (550-50) 40/0.8 à Solving for FiO2 à = 0.5 So the paent needs, at least 50% O2 50% O2? How? Tough! You will need several big tanks. NC won t do it A Paral rebreather mask will do Try to get that by the FAA and United, American, etc. Good Luck!!!! Length of Tubing Remember the Hagen- Poiseuille (pwaa- zuh- ee) Law/ Equaon ΔP= (8nlV)/(πr4) ΔP à Pressure difference n à Viscosity l à length of pipe V à flow rate r à radius of pipe Hagen- Poiseuille ΔP= (8nlV)/(πr4) Then length maers But for praccal purposes, if the tubing is less than 100, things should be OK 7

100% O2, sats are at 100% ABG: ph: 7.40 CO2: 40 PaO2: 250 mmhg HCO3: 26 Is this OK?

8) à ~660 mmhg Above 550 should be OK And the PA should closely match the Pa (100-150 mmhg difference OK at high O2 concentraons) If your paent s PaO2 is 250, then

as climbing or space acvies Predicons 1875 Gaston Tissandier, Joseph Croce- Spinelli and Théodore Sive.

8 100% O2? ANOTHER CASE You arrive to the intensive care unit and have a paent with narcoc overdose recently placed on a venlator with good breaths and you are giving FiO2 100% O2, sats are at 100% ABG: ph: 7.40 CO2: 40 PaO2: 250 mmhg HCO3: 26 Is this OK? 100% O2 According to the alveolar gas equaon, somebody on 100% O2 should have a PaO2 of à (1*(763-50) ) - (40/0.8) à ~660 mmhg Above 550 should be OK And the PA should closely match the Pa ( mmhg difference OK at high O2 concentraons) If your paent s PaO2 is 250, then there is severe lung disease This the main use of the alveolar equaon To predict & assess pts in different clinical condions During illness And during acvity, such as climbing or space acvies Predicons 1875 Gaston Tissandier, Joseph Croce- Spinelli and Théodore Sive. Set to break the altude record 8,600 mts ( ~270 mmhg) Joe and Theo died Gaston with mental damage What was the predicted PaO2 and sats at that altude? PA= (0.21*(270-50)) (40/0.8) PA = Neg #! Compensaon by hypervenlaon PA= (0.21*(270-50)) (7/0.8) PA= on the 30s! Sats: ~ 50% The Jump Mt Everest 2012 Felix Baumgartner 38k mts (24 miles) Broke speed of sound Suit pressurized at 3.5 psi 3.5 psi = 180 mmhg Alveolar Equaon (1*(180-50) ) 50 ) = PA= 80 Sats on the high 90s. That s good for decision making and acvity 8

8,850 m (29 k ) 250 mm Hg PA= FiO2*(Atm- H20) (CO2/RQ) PA= 0.21 * (250 50) (40/0.8) PA= VERY LOW Compensaon: Hypervenlaon with respiratory alkalosis PA= 0.21 * (250 50) (7/0.

alveolar equaon: atm pressure, FiO2, and CO2 Respiratory Variables CO 2 O 2 1 GASES (CO2 & O2) NEURO Control 2 LUNG ANATOMY VENTILATION MECHANICS 3 DIFFUSION INTO BLOOD Alveolar/Capillary Finally,

9 8,850 m (29 k ) 250 mm Hg PA= FiO2*(Atm- H20) (CO2/RQ) PA= 0.21 * (250 50) (40/0.8) PA= VERY LOW Compensaon: Hypervenlaon with respiratory alkalosis PA= 0.21 * (250 50) (7/0.8) PA=42 8 = 34 mmhg Mt Everest Short Summary Atmospheric pressure, along with FiO2 are two important components for hemoglobin saturaon PaO2 should be close to PAO2, if not, there is a problem somewhere (lungs? Heart? Other?) 30 mmhg à50% and 60 mmhg à 90% Paents with chronic lung disease who need oxygen (and others) should be assessed before traveling on planes or to high altude cies Bear in mind the variables of the alveolar equaon: atm pressure, FiO2, and CO2 Respiratory Variables CO 2 O 2 1 GASES (CO2 & O2) NEURO Control 2 LUNG ANATOMY VENTILATION MECHANICS 3 DIFFUSION INTO BLOOD Alveolar/Capillary Finally, and very briefly HEMOGLOBIN 4 GAS TRANSPORT IN BLOOD Hgb and Plasma CO 2 O 2 5 CELLULAR DIFFUSION OUTSIDE VIDEO SOURCE Hemoglobin 2α + 2β subunits Haldane: Tissues: CO2 pickup facilitates O2 release Lungs: O2 loading increases CO2 release Bohr: Tissues: O2 release facilitates H+ pickup Lungs: O2 pickup facilitates H+ release 2,3- DPG Hgb releases O2 from the 2β subunits first The, 2,3- DPG at ssues binds the 2β DPG binding changes the shape of Hgb This allosteric change promotes the release of O2 by the 2β subunits W/o DPG, Hbg at 50% efficiency (like myoglobin) Live high, train low High: + DPG, mitochondria, EPO, Hct Low: longer peak levels when training hps:// Oxygen Transport from Lungs to Cells 10/2013 hp://faculty.etsu.edu/currie/hemoglobin.htm 9

Hyperbaric Chamber 98% of O2 carried by Hgb (%Sat*1.34*Hgb) + (PaO2 *.003) Oxygen Content (CaO2) Arterial (97-100% sats) 100 * 1.34 * 15mg/dl = 20.10 ml/dl 100 mmhg * 0.

3 ml/dl Venous CvO2 (60-80% sats) 80 * 1.34 * 15mg/dl = 16.08 ml/dl 45 mmhg * 0.

with the oxygen that is diluted. No hgb needed! At 6 atm * 760 = 4,560 mmhg 4,560 * 0.0031 = 14.

increased pressure. At 3 atm * 760 = 2,280 mmhg 2,280 * 0.00.31 = 7.

10 Hyperbaric Chamber 98% of O2 carried by Hgb (%Sat*1.34*Hgb) + (PaO2 *.003) Oxygen Content (CaO2) Arterial (97-100% sats) 100 * 1.34 * 15mg/dl = ml/dl 100 mmhg * = 0.3 ml/dl Venous CvO2 (60-80% sats) 80 * 1.34 * 15mg/dl = ml/dl 45 mmhg * = 0.14 ml/dl Oxygen Consumpon (VO2) Q * (CaO2- CvO2) à CaO2- CvO2à~ 5ml/dl * Cardiac Output The amount of oxygen needed could be supported in a hyperbaric chamber (2-6 atm) just with the oxygen that is diluted. No hgb needed! At 6 atm * 760 = 4,560 mmhg 4,560 * = ml/dl Short Summary Hgb is the major carried of O2 Allosteric effects: Haldane, Bohr, and 2,3 DPG Hyperbaric chambers can provide a great amount of dissolved O2 due to the increased pressure. At 3 atm * 760 = 2,280 mmhg 2,280 * = 7.07 ml/dl Acid- Base Nomograms FINALLY ABG Interpretaon Nomogram Use these lile graphs to figure out if your paent is in : Chronic or Acute Respiratory or Metabolic Acidosis or Alkalosis Final Summary AND THAT S IT! Now to the final summary 21% of O2 in the atmosphere But pressure varies and it affects the real amount of oxygen available The alveolar equaon is an important formula to develop clinical predicons There are many oxygen delivery devices, familiarize with them. Hemoglobin is affected by allosteric changes: Haldane, Bohr, and 2,3 DPG You may use an ABG nomogram while you get used to interpret gases 10

11 Take Home Points The larger the dal breath, the lower the FiO2 provided by NC. One lpm is not the same in a neonate, a child or an adult. If you have two paents on 100% FiO2 and the saturaon of both is 100%, that doesn t mean that the lungs are OK. Pa of 100 vs Pa of 500 mmhg Keep in mind the atmospheric pressure when taking decisions about O2 in planes or going to other cies. Use the alveolar equaon PAO2= (FiO2 * (AtmPress H20) ) - PCO2/RQ Thanks!! Oxygen Basics Jesus R. Guajardo, MD, MHPE, PhD 11

PICU Resident Self-Study Tutorial The Basic Physics of Oxygen Transport. I was told that there would be no math!

Physiology of Oxygen Transport PICU Resident Self-Study Tutorial I was told that there would be no math! INTRODUCTION Christopher Carroll, MD Although cells rely on oxygen for aerobic metabolism and viability,