This document discusses various medical gases including oxygen, carbon dioxide, helium, and their properties, preparation, storage, clinical uses, and safety considerations. It provides details on oxygen therapy including indications, assessment, delivery methods, complications like toxicity, and monitoring. The oxygen cascade and hypoxia types are explained. Carbon dioxide properties and uses in anesthesia are covered. Helium properties and use in partial airway obstruction are outlined. Methods of gas analysis are also summarized.
For my colleagues and medical students out there who need to either read or present the subject of hypoxia in surgical patients. I hope you find this one helpful.
For my colleagues and medical students out there who need to either read or present the subject of hypoxia in surgical patients. I hope you find this one helpful.
Oxygen therapy by Dr Arun Gangadharan
This ppt cover basics of oxygen therapy, its indication and the various methods to give oxygen.
Reference- Fishman's Pulmonary Diseases and Disorders
Pediatrics notes about "Acute Respiratory Failure". These notes were published in 2018.
You can download them from
- Telegram: https://t.me/pediatric_notes_2018
- Mediafire: http://www.mediafire.com/folder/u5u60m184t9z7/Pediatric_Notes_2018
OXYGEN THERAPY is vast diversified topic.
in the slide share, we have tried to compile all detailed information in brief.
the slides are well versed and all information have been garnered from verified sources.
all recent guidelines, standard textbooks have been referred.
COURTESY- DEPARTMENT OF CRITICAL CARE MEDICINE,
ABVIMS & DR RML HOSPITAL, NEW DELHI.
Oxygen therapy by Dr Arun Gangadharan
This ppt cover basics of oxygen therapy, its indication and the various methods to give oxygen.
Reference- Fishman's Pulmonary Diseases and Disorders
Pediatrics notes about "Acute Respiratory Failure". These notes were published in 2018.
You can download them from
- Telegram: https://t.me/pediatric_notes_2018
- Mediafire: http://www.mediafire.com/folder/u5u60m184t9z7/Pediatric_Notes_2018
OXYGEN THERAPY is vast diversified topic.
in the slide share, we have tried to compile all detailed information in brief.
the slides are well versed and all information have been garnered from verified sources.
all recent guidelines, standard textbooks have been referred.
COURTESY- DEPARTMENT OF CRITICAL CARE MEDICINE,
ABVIMS & DR RML HOSPITAL, NEW DELHI.
HOT NEW PRODUCT! BIG SALES FAST SHIPPING NOW FROM CHINA!! EU KU DB BK substit...GL Anaacs
Contact us if you are interested:
Email / Skype : kefaya1771@gmail.com
Threema: PXHY5PDH
New BATCH Ku !!! MUCH IN DEMAND FAST SALE EVERY BATCH HAPPY GOOD EFFECT BIG BATCH !
Contact me on Threema or skype to start big business!!
Hot-sale products:
NEW HOT EUTYLONE WHITE CRYSTAL!!
5cl-adba precursor (semi finished )
5cl-adba raw materials
ADBB precursor (semi finished )
ADBB raw materials
APVP powder
5fadb/4f-adb
Jwh018 / Jwh210
Eutylone crystal
Protonitazene (hydrochloride) CAS: 119276-01-6
Flubrotizolam CAS: 57801-95-3
Metonitazene CAS: 14680-51-4
Payment terms: Western Union,MoneyGram,Bitcoin or USDT.
Deliver Time: Usually 7-15days
Shipping method: FedEx, TNT, DHL,UPS etc.Our deliveries are 100% safe, fast, reliable and discreet.
Samples will be sent for your evaluation!If you are interested in, please contact me, let's talk details.
We specializes in exporting high quality Research chemical, medical intermediate, Pharmaceutical chemicals and so on. Products are exported to USA, Canada, France, Korea, Japan,Russia, Southeast Asia and other countries.
263778731218 Abortion Clinic /Pills In Harare ,sisternakatoto
263778731218 Abortion Clinic /Pills In Harare ,ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group of receptionists, nurses, and physicians have worked together as a teamof receptionists, nurses, and physicians have worked together as a team wwww.lisywomensclinic.co.za/
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
3. Preparation :Large scale commercial preparation is
done by fractional distillation of air
In some conditions, Electrolysis of
water and other chemical reactions
are used to prepare O2.
Storage : O2 is stored in Liquid form in insulated
tanks.
or as Gas form in cylinders at high
pressures (102783.8 mm Hg. or 2000
psig or 13700 kpa)
A Pressure regulator maintain a
constant supply pressure of 400 kpa
(60 psi or 3001mmHg) in hospital pipe
sytem
4. Oxygen :
Properties:
Molecular Weight 32.00
Relative Density 1.105
Boiling Point -1830C
Critical Temperature - 1180C
Melting Point -2180C
Abundance Atmosphere 20.95%
Human body 65%
Solubility in water at 370C 2.4 ml O2 / 100 ml of H2O
Solubility in Blood at 370C 0.003 ml/ 100 ml blood
5. Oxygen Lack (Hypoxia)
• Failure of the tissue to receive adequate
quantities of Oxygen is variously described as
anoxia, hypoxia or oxygen lack
• Anoxia means total lack of oxygen
6. OXYGEN THERAPY ….. WHAT?
Administration of O2 in concentration more than in
ambient air
↑Partial Pr of O2 in insp. Gas (Pi o2)
↑Partial Pr of O2 in alveoli (PAo2)
↑Partial Pr of O2 in arterial blood (Pao2)
7. What is the Oxygen Cascade?
The process of declining oxygen tension from atmosphere to
mitochondria
Atmosphere air (dry) (159 mm Hg)
↓ humidification
Lower resp tract (moist) (150 mm Hg)
↓ O2 consumption and alveolar ventilation
Alveoli PAO2 (104 mm Hg)
↓ venous admixture
Arterial blood PaO2 (100 mm Hg)
↓ tissue extraction
Venous blood PV O2 (40 mm Hg)
↓
Mitochondria PO2 (7 – 37 mmHg)
8. OXYGEN CASCADE
• PO2 drop in stages from
158mmHg (21KPa) in dry
air to the low levels in the
mitochondria
• Pasteur point- level of
PO2 fall in the
mitochondria to 1-2mm
Hg (0.2 Kpa)where
aerobic metabolism
stops, anaerobic
metabolism will start and
acidosis will occur.
11. Classification of Hypoxia
1. Hypoxic Hypoxia: defective mechanism of oxygenation in
the lungs due to
a Reduced PiO2 • Decrease FIO2 Rebreathers.
Hypoxic gas supply
• Decrease Barometric pressure High altitude
b Fink effect / diffusion
Hypoxia
•Solubility N2O more than N2
c Reduced alveolar
ventilation
• Absolute
• Relative – Fever, Seizures, Halothane shakes
d Reduced diffusing
capacity
• Due to thickening of alveolar capillary membrane
e Venous admixture • True shunt – Rt to Lt shunt
• Intrapulmonary shunting in Zones of Low V/Q ratio
e.g. atelectasis etc.
12. 2. Stagnant hypoxia –type of hypoxia which is
caused by inadequate blood flow ,which
results in less oxygen available to the tissues
Decrease tissue perfusion
General – Decrease Cardiac output
Local – Arterial or venous occlusion e.g.
atheroma,
embolism,
trauma,
Vasoconstriction.
13. 3. Histotoxic hypoxia– adequate amount of oxygen
is inhaled through the
lungs and delivered to
tissues,but the tissues are
unable to use the oxygen
sodium nitroprusside contains a cyanide radical,
so overdose of this drug can cause histotoxic
hypoxia
Low P5O - Partial pressure of O2 at which Hb is 50%
saturated. normally 27mm Hg (3.6 kpa).
Low P50 – Shift to Left of Hb dissociation
curve. In this way, low P50 can produce
tissue hypoxia
Cause of shift to left is alkalosis,redused 2,3
DPG,hypothermia
14. 4. Anaemic hypoxia - due to
Decrease concentration of functional hemoglobin
PaO2 is normal
(a)Anemia – Increase 2,3 DPG Synthesis – shift to Rt – unloading
O2 blood to tissue.
15. (b) CO Poisoning –affinity of Hb for CO is about 250
times higher then O2
Coal gas is common cause of co poisoning
Commercial paint remover contain methyl chloride
has caused sever co poisoning
16. Methaemoglobinaemia - Methemoglobin lacks the
electron that is needed to form a bond with oxygen
and, thus, is incapable of oxygen transport.
Sulphhaemoglobinaemia- rare blood condition that
occurs when a sulfur atom is incorporated into the
hemoglobin molecule.
17. Post operative Hypoxia –
i. Fink effect
ii. Increase V / Q mismatch due to decrease
FRC.
iii.Stagnant Hypoxia
iv.Hypoventilation
(a) Drugs
(b) Obstruction
(c) Pain
(d) Intra operative Hyperventilation.
18. Effects of Hypoxia –
Depends on :
Duration, degree of hypoxia
Idiosyncracy of individual
Other factors such as drugs, disease & temperature.
CVS Systemic vascular resistance reduced
Cardiac output increased
Peripheral chemoreceptor stimulation – increase in
sympathetic activity
CNS Cerebral vasodilation
RS Ventilation increased
Pulmonary vascular resistance increased
METABOLISM Aerobic metabolism reduced
Anaerobic metabolism – metabolic acidosis
ORGAN FAILURE
Haemoglobin Cyanosis
Reduced haemoglobin is a better buffer
Reduced solubility of haemoglobin S in chronic hypoxia
20. Objectives:
To correct documented or suspected acute
Hypoxemia.
To Decrease symptoms associated with chronic
Hypoxemia.
To Decrease workload that hypoxemia imposes
on the cardiopulmonary system.
21. Indications
• Documented hypoxemia
• Adults, children, and infants : PaO2 < 60 mm
Hg or SaO2 < 90%
• Neonates, PaO2 < 50, SaO2 < 88%, or capillary
PO2 < 40mm Hg
• Acute care situations in which hypoxemia is
suspected
• Acute myocardial infarction.
• Cardiogenic pulmonary edema
• Acute Lung injury
• Acute respiratory distress syndrome
• Pulmonary fibrosis
• Cyanide poisioning
22. ASSESSMENT
• The need for oxygen therapy should be
assessed by
1. monitoring of ABG - PaO2, SpO2
2. clinical assessment findings.
23. PaO2 as an indicator for Oxygen
therapy
• PaO2 : 80 – 100 mm Hg : Normal
60 – 80 mm Hg : cold, clammy
extremities
< 60 mm Hg : cyanosis
< 40 mm Hg : mental deficiency
memory loss
< 30 mm Hg : bradycardia
cardiac arrest
PaO2 < 60 mm Hg is a strong indicator for
oxygen therapy
24. Clinical Signs of Hypoxia
Finding Mild to Moderate Severe
Respiratory Tachypnea Tachypnea
Dyspnea Dyspnea
paleness Cynosis
Cardiovascular Tachycardia Tachycardia, eventual bradycardia,
arrhythmia
Mild hypertension,
peripheral
vasoconstriction
Hypertension and eventual Hypotension
c.n.s Restlessness Somnolence
Disorientation Confusion Distressed appearance
Headache Blurred vision
Lassitude Tunnel vision, Loss of coordination,
impaired judgment, Slow reaction time,
Manic-depressive activity, Coma,
Clubbing.
27. Oxygen Content (Co2)
Amount of O2 carried by 100 ml of blood
Co2 =Dissolved O2 + O2 Bound to hemoglobin
Co2 = Po2 × 0.0031 + So2 × Hb × 1.34
(Normal Cao2 = 20 ml/100ml blood
Normal Cvo2 = 15 ml/100ml blood)
Co2 = arterial oxygen content (vol%)
Hb = hemoglobin (g%)
1.34 = oxygen-carrying capacity of hemoglobin
Po2 = arterial partial pressure of oxygen (mmHg)
0.0031 = solubility coefficient of oxygen in plasma
28. Oxygen Flux
Amount of of O2 leaving left ventricle per minute.
= CO × Hb sat x Hb conc x 1.34
100 100
= 5000 x 97 x 15.4 x 1.34
100 100
= 1000 ml/min
CO = cardiac output in ml per minute.
Do2 = oxygen flux
29. Complications of Oxygen therapy
1. Oxygen toxicity
2. Depression of ventilation
3. Retinopathy of Prematurity
4. Absorption atelectasis
5. Fire hazard
30. 1. O2 Toxicity
• Primarily affects lung and CNS.
• 2 factors: PaO2 & exposure time
• CNS O2 toxicity (Paul Bert effect)
– occurs on breathing O2 at pressure > 1 atm
– tremors, twitching, convulsions
32. Pulmonary O2 Toxicity (Lorrain-Smith
effect)
Mechanism: High pO2 for a prolonged period of time
↓
intracellular generation of free radicals e.g.:
superoxide,H2O2 , singlet oxygen
↓
react with cellular DNA, sulphydryl proteins &lipids
↓
cytotoxicity
↓
damages capillary endothelium,
↓
35. How much O2 is safe?
100% - not more than 12hrs
80% - not more than 24hrs
60% - not more than 36hrs
Goal should be to use lowest possible FiO2
compatible with adequate tissue oxygenation
36. Indications for 70% - 100% oxygen
therapy
1. Resuscitation
2. Periods of acute cardiopulmonary instability
3. Patient transport
37. 2. Depression of Ventilation
• Seen in COPD patients with chronic hypercapnia
• Mechanism
↑PaO2
suppresses peripheral V/Q mismatch
chemoreceptors
depresses ventilatory drive ↑ dead space/tidal volume ratio
↑PaCO2
38. 3. Retinopathy of prematurity (ROP)
• Premature or low-birth-weight infants who receive
supplemental O2
• Mechanism
↑PaO2
↓
retinal vasoconstriction
↓
necrosis of blood vessels
↓
new vessels formation
↓
Hemorrhage → retinal detachment and blindness
To minimize the risk of ROP - PaO2 below 80 mmHg
39. 4. Absorption atelectasis
100% O2
oxygen
nitrogen
PO2 =673
PCO2 = 40
PH2O = 47
A B
A – UNDERVENTILATED
B – NORMAL VENTILATED
41. 5. Fire hazard
• High FiO2 increases the risk of fire
• Preventive measures
– Lowest effective FiO2 should be used
– Use of scavenging systems
– Avoid use of outdated equipment such as
aluminium gas regulators
– Fire prevention protocols should be followed for
hyperbaric O2 therapy
42. Oxygen challenge concept
↑ FiO2 by 0.2
↑ PaO2 > 10 mmHg ↑ PaO2 < 10 mmHg
↑ PaO2 < 10 mmHg in response to an oxygen challenge of 0.2 –
refractory hypoxemia
43. Implications of Oxygen challenge
concept
To identify refractory hpoxemia (as it does not
respond to increased FiO2)
Refractory hpoxemia depends on increased
cardiac output to maintain acceptable FiO2
Potentially deleterious effect of increased
FiO2 can be avoided
44. Carbon dioxide(CO2)
• First isolated by Black in
1757
• Physiological
significance was
appreciated by Yandell
Henderson & J.S.
Haldane
45. Properties of CO2
• Colourless
• Irritant to mucosa when inhaled in high
concentration
• CO2 found in atmosphere at a conc of 0.03 vol
percent
• CO2 stored in grey cylinder in liquid form
46. Preparation
–by product in manufacture of hydrogen and
process of fermentation
in laboratory
NaHCO3 +HCl --- NaCl+H2O+Co2
47. Use of CO2 in anaesthesia
• To rise the PCO2 when discontinuing IPPV so
that spontaneous respiration is established
more quickly
• To stimulate respiration after induction of
anaesthesia. So patient breath
N2O/O2/halothane mixture spontaneously
• Co2 is sometimes used to stimulate
respiration to facilitate blind nasal intubation
49. Properties of He
• Inert, colourless,odourless gas
• Apart from hydrogen Helium is the lightest
known gas
• Molecular weight = 4
• Relative density= 0.14 (air= 1)
• Diffuse through skin and rubber
50. Preparation of Helium
• Main source: Natural gas is found in United
States in Texas and Kansas
• Other gases which are found in natural gas are
removed by absorption, liquefaction or
scrubbing with water and sodium hydroxide
51. Clinical uses of helium
• Partial respiratory obstruction
• for example in tracheal stenosis patient:-
80percent helium and 20 percent oxygen
having a relative density of 0.33 (air=1)is
administered
• It is important that it should be administered
via a well fitted face mask because if it is
diluted with air , the advantage of low relative
density is lost
52. Principles of gas analysis
• In anaesthesia practice, knowledge of the
concentration of a gas like O2, CO2 or N2O is
often required for the satisfactory
management of the patient
Normally enzyme such as superoxide dismutase rapidly inactivates superoxide molecule.
In presence of high FiO2, free radicals overwhelm O2 free radicals and cause cell damage
When COPD patients with chronic hypercapnia breathe moderate to high O2 conc, they hypoventilate d/t suppression of the hypoxic drive.
Nitrogen normally is the most plentiful gas in both the alveoli, blood and cellular water.