oxygen therapy guidelines for resident doctors and nurses

1. Oxygen Therapy in COVID-19
DR A. K. GUPTA MD ( PEDIATRICS)
CHIEF MEDICAL OFFICER ( SAG)
GOVERNMENT OF NCT OF DELHI

2. Additionally in moderate or severe disease at
high risk of progression
Consider Remdesivir for up to 5 days (200 mg IV on day
1 followed by 100 mg IV OD for next 4 days)
To be started within 10 days of onset of symptoms, in those
having moderate to severe disease with high risk of progression
(requiring supplemental oxygen), but who are NOT on IMV or
ECMO
No evidence of benefit for treatment more than 5 days
NOT to be used in patients who are NOT on oxygen support or in
home setting
Monitor for RFT and LFT (remdesivir not recommended if eGFR
<30 ml/min/m2; AST/ALT >5 times UNL) (not an absolute
contraindication)
Adult patient diagnosed with COVID-19
Dexamethasone 6 mg/day or
equivalent dose of
methylprednisolone (32 mg in 4
divided doses) usually for 5 to 10
days or until discharge, whichever is
earlier.
Patients may be initiated or
switched to oral route if stable
and/or improving
There is no evidence for benefit for
systemic steroids in those NOT
requiring oxygen supplementation,
or on continuation after discharge
Anti-inflammatory or
immunomodulatory therapy (such
as steroids) can have risk of
secondary infection such as invasive
mucormycosis when used at higher
After clinical improvement, discharge
as per revised discharge criteria
AIIMS/ ICMR-COVID-19 National Task Force/ Joint Monitoring Group (Dte.GHS)
Ministry of Health & Family Welfare, Government of India
CLINICAL GUIDANCE FOR MANAGEMENT OF ADULT COVID-19 PATIENTS
Revised on 05/01/2023
Severe disease
Mild disease
Upper respiratory tract symptoms
and/or fever WITHOUT shortness
of breath or hypoxia
Home Isolation & Care
(Refer to relevant guideline)
ADMIT IN WARD ADMIT IN HDU/ICU
saturation (by applying a SpO probe
to fingers)
Stay in contact with treating
physician
MUST DOs
Physical distancing, indoor mask
use, hand hygiene
Symptomatic management
(hydration, anti-pyretics, anti-
tussive)
Monitor temperature and oxygen
2
Moderate disease
Any one of:
1.Respiratory rate ≥24/
min,
breathlessness
2.SpO2
: 90% to ≤ 93% on room air
Oxygen Support:
patients with COPD)
Preferred devices for oxygenation:
non-rebreathing face mask
Awake proning encouraged in all
patients requiring supplemental
oxygen therapy (sequential
position changes every 2 hours)
Anti-inflammatory or
immunomodulatory therapy:
dose or for longer than required
Anticoagulation:
Prophylactic dose of unfractionated
heparin or Low Molecular Weight
Heparin (weight based e.g.,
enoxaparin 0.5mg/kg per day SC).
There should be no
contraindication or high risk of
bleeding
Monitoring:
Clinical Monitoring: Respiratory
rate, Hemodynamic instability,
Change in oxygen requirement
Serial CXR; HRCT chest to be done
ONLY if there is worsening
Lab monitoring: CRP, D-dimer,
blood sugar 48 to 72 hrly; CBC, KFT,
LFT 24 to 48 hrly
Any one of:
1.Respiratory rate >30/min,
breathlessness
2.SpO2 < 90% on room air
Target SpO : 94-96% (88-92% in
2
Seek immediate medical attention if:
Difficulty in breathing or SpO2 ≤ 93%
High grade fever/severe cough,
particularly if lasting for >5 days
A low threshold to be kept for those
with any of the high-risk features*
Respiratory & Cardiovascular Support:
Consider use of NIV (Helmet or face mask
interface depending on availability) in
patients with increasing oxygen
requirement, if work of breathing is LOW
Consider use of HFNC in patients with
increasing oxygen requirement
Intubation should be prioritized in
patients with high work of breathing /if
NIV is not tolerated
Use institutional protocol for ventilatory
management when required
Need for vasopressors to be considered
based on clinical situation
Anti-inflammatory or
immunomodulatory therapy:
Dexamethasone 6 mg/day or equivalent
dose of methylprednisolone (32 mg in 4
divided doses) usually for 5 to 10 days or
until discharge, whichever is earlier. No
evidence for benefit in higher doses.
Anti-inflammatory or immunomodulatory
therapy (such as steroids) can have risk of
secondary infection such as invasive
mucormycosis when used at higher dose
or for longer than required
Anticoagulation:
Prophylactic dose of unfractionated
heparin or Low Molecular Weight Heparin
(weight based e.g., enoxaparin 0.5mg/kg
per day SC). There should be no
contraindication or high risk of bleeding
Supportive measures:
Maintain euvolemia (if available, use
dynamic measures for assessing fluid
responsiveness)
If sepsis/septic shock: manage as per
existing protocol and local antibiogram
Monitoring:
Clinical Monitoring: Work of breathing,
Hemodynamic instability, Change in
oxygen requirement
Serial CXR; HRCT chest to be done ONLY if
there is worsening
Lab monitoring: CRP, D-dimer, blood sugar
48 to 72 hrly; CBC, KFT, LFT 24 to 48 hrly
*High-risk for severe disease or
mortality
Age > 60 years
Cardiovascular disease and CAD
Diabetes mellitus and other
immunocompromised states (such
as HIV)
Active tuberculosis
Chronic lung/kidney/liver disease
Cerebrovascular disease
Obesity
Unvaccinated
Antibiotics should not be used unless
there is clinical suspicion of bacterial
infection
Possibility of coinfection of COVID-19
with other endemic infections must
be considered
Systemic corticosteroids are not
indicated in mild disease
DO NOT USE IN COVID-19
Lopinavir-ritonavir
Hydroxychloroquine
Ivermectin
Neutralizing monoclonal antibody
Convalescent plasma
Molnupiravir
Favipiravir
Azithromycin
Doxycycline
Additionally in rapidly progressing moderate
or severe disease
Consider Tocilizumab preferably within 24-48 hours of onset
of severe disease/ ICU admission [4 to 6 mg/kg (400 mg in 60
kg adult) in 100 ml NS over 1 hour] if the following conditions
are met:
Rapidly progressing COVID-19 not responding adequately
to steroids and needing oxygen supplementation or IMV
Preferably to be given with steroids
Significantly raised inflammatory markers (CRP and/or IL-6)
Rule out active TB, fungal, systemic bacterial infection
Long term follow up for secondary infections (such as
reactivation of TB, flaring of Herpes)

3. When Oxygen Therapy is Not Required?
• Patients with SpO2 ≥ 92
• Breathless Patients with normal SpO2 [Oxygen is a Treatment of Hypoxemia
not breathlessness]
• COPD patients with SpO2 ≥ 88

4. When to Start Oxygen Therapy?
• Oxygen therapy is indicated when peripheral oxygen saturation (SpO2) < 92%
[Do not start Oxygen if SpO2 ≥ 92%].
• In patients suffering from Chronic obstructive pulmonary disease, oxygen
therapy is indicated when SpO2 < 88%]-
In COPD patients do not start Oxygen if SpO2 ≥ 88%]
• Awake Proning for 12 - 16 hours per day is recommended when SpO2 starts
falling < 94.
• Hypoxia (SpO2 < 90) is a medical emergency and oxygen administration
should be started immediately.

5. When to Start Oxygen Supplementation &
Target Range
sPO2 Target sPO2
• Without COPD - < 92 92-96%*
• With COPD - < 88 88-92%
[*Target 94- 96%% in children & pregnant woman]

6. Oxygen Therapy Devices
1.Low Flow Devices- Nasal prong/ cannula,
Face mask, Non Rebreathing Mask (NRBM)
2. High Flow Devices- Venturi Mask, HFNO

8. Flow rate & FiO2 of Various O2 Delivery Devices
Device Flow rate FiO2 (%)
• Nasal cannula/Prongs*: 1-5 L/min 0.24-0.40
• Face mask* 5-10 L/min 0.40-0.60
• Venturi mask 2-15 L/min 0.24-0.60
• NRBM 10-15 L/min 0.90-1.00
(*FiO2= 20+ Flow in LPM X4)

9. Practical Considerations About O2 Rx
• Oxygen - A drug - Prescribed on drug chart (device, FiO2, Flow rate)
• SpO2 : To be Recorded as a Vital Sign
• The SpO2 should be measured before starting O2 Rx whenever possible
but never delay oxygen therapy for seriously ill patients.
• Hypoxemia ( Spo2 <90) is a medical emergency as it can lead to
multiorgan failure so it should be treated immediately.
• Target of SpO2 range to be achieved should be specified (e.g. 92-96%)
• Humidification is not required for the delivery of low-flow oxygen
(mask or nasal cannula) or for the short-term use of high-flow oxygen (
<24 hour)
• Do not allow hypoxemia to occur during nebulization
• Sudden cessation of supplementary oxygen therapy can cause life-
threatening rebound hypoxemia

10. Dangers of O2 Therapy
• Lorraine Smith effect: O2 is toxic to the lungs when high FiO2 (>0.60) is
administered ≥24 hours.
• Hyperoxia associated acute lung Injury : Reactive O2 species damage the
lipid membranes, proteins, and nucleic acids- Pulmonary oedema,
haemoptysis
• Absorption Atelectasis (Occurs If FiO2 100%, But not if O2 <80%)
• Paul Bert effect- CNS toxicity : Headache, , Irritability, Anxiety, Dizziness,
Fatigue, Blurring of vision, Tinnitus, Nausea, Seizure, Coma
• Increase in Infarct size in Acute Myocardial Infarction
• Increase in Cerebral Infarct in acute stroke
Note : Oxygen toxicity can be minimized by keeping lowest
possible FiO2 to achieve desired minimum SpO2, preferably
FiO2 below 0.40 -0.50.

11. Oxygen is a drug and should be duly
prescribed recording following details ….
• Baseline SpO2 in Room Air
• Desired SpO2 Target:
- Adults (Target: 92% - 96%)
- COPD patients (Target: 88% - 92%) and
- Pregnant women and children (Target: 94% - 96%)
• Oxygen administration device to be used- nasal-prongs, or simple
oxygen face mask, or Non-Rebreathing Mask [NRBM}, or Venturi
mask, or High Flow Nasal Cannula [HFNC] etc.

12. Initial O2 Flow to be as per Baseline SpO2
• If SpO2 < 85% : 10-15 L/min (NRBM) for short duration as
emergency rescue therapy for severe hypoxia.
• When minimum target SpO2 of 92% is achieved, the oxygen delivery
may be done by using simple oxygen face mask.
• If SpO2 > 85%- < 90%: 2 - 4 L/min (Nasal prongs, can go up-to
flow of 5 L/min if target not achieved) or (face mask 5 L/min, can go
up-to flow of 10 L/min to achieve minimum desired SpO2 target).
• In COPD patients start low flow oxygen by nasal prongs @ 1-2
L/min to prevent danger of hypoventilation.

13. Maintaining Minimum Desired SpO2 (≈92%)
Maintaining Minimum Desired SpO2 (≈ 92%) by administering Oxygen
at Minimum FiO2 (fraction of inspired oxygen) as Oxygen is toxic as
well.
• If FiO2 of near 0.95 - 1.00 is used for long time, there may be risk of
absorption atelectasis and gas exchange will decrease in lungs despite
oxygen therapy
• If FiO2 > 0.6 is given for ≥ 24 hours, ARDS can develop due to O2 toxicity.
• If SpO2 crosses 96%, decrease O2 flow by 1 Liter/min and re-check
SpO2 after 5 minutes with aim to keep SpO2 maximum up-to 96%.
• When SpO2 is stable on a particular FiO2 and O2 Flow rate for 24
hours, attempt a gradual stepping down.

14. Stepping Up Oxygen Therapy As Required
Stepping up @ 1 L/min oxygen flow every 5-minute, checking SpO2
every 5 minutes till minimum desired SpO2 is achieved
(SpO2 92% minimum, COPD patient SpO2 88% minimum)
• Nasal cannula- max 5 L/min flow and FiO2 of 40%
• Face mask- max 10 L/min flow and FiO2 of 60%
• NRBM- max 15 L/min flow and FiO2 of 100%
• Venturi Mask- max15 L/min flow and FiO2 of 60%
• HFNO – maximum up to 60L /min flow and FiO2 100%
max up to 25L /min flow in children

15. Stepping Down O2 flow and FiO2
• When patient is stable on a particular Oxygen Flow and FiO2 for 24
hours, stepping down of O2 flow is mandatory to prevent Oxygen
Wastage and Oxygen Toxicity
• Stepping down should be gradual as sudden discontinuation of O2
can cause severe ‘Rebound Hypoxia’
• Rate of Stepping Down: Step down @ 1 L/min oxygen flow every 4 -
8 hours till patient is stable (normal desired SpO2 92% - 96%) on 2
L/min (FiO2 < 0.4) before discontinuation of O2 Rx.
• Continue monitoring SpO2 after discontinuing Oxygen for at least 24
hours (two-consecutive SpO2 readings to be taken and reported normal)

16. Recognize Severe Hypoxemic Respiratory
Failure while on Standard O2 Rx
For patients who continue to deteriorate despite using NRBM mask (flow rates of 10–15 L/min FiO2 0.95) perform ABG
Analysis.
ABG Analysis :- Normal pH (7.35-7.45), PaO2 (80-100 mmHg), PaCO2 (35-45 mm HG), HCO3- (22 -26 mEq/L)
Step 1 : Analyze pH: < 7.35 Acidosis; > 7.45 : Alkalosis
Step 2: Analyze PaCO2: < 35 Resp. Alkalosis ; > 45 Resp. Acidosis
Step 3: Analyze HCO3- : <22 Met. Acidosis; > 26 Met. Alkalosis
Respiratory Failure Two Types:
• Type 1 Respiratory failure [ PaO2 < 60 mmHg with Normal PaCO2 or Reduced Pa CO2]: Hypoxia : HFNO: Start High Flow
Nasal Oxygen (HFNO) to reduce the need for mechanical ventilation by intubation. Adult HFNO systems (max flow up to 60
L/min of gas flow and FiO2 up to 1.0) and Pediatric circuits max flow up to 25 L/min.
Patients receiving HFNO should be given 1 hour trial, but if condition deteriorates should be put on mechanical
intubation
• Type 2 Respiratory Failure [PaCO2>50 mmHg with paO2 <60 mm HG] : Hypoxia with Hypercapnia: O2 Support by BiPAP ( If
patient is conscious and there is no hemodynamic instability) , Mechanical Ventilation (if hemodynamic instability,
multiorgan failure, abnormal mental status)

17. Non Invasive Ventilation
CPAP/BiPAP
Indication : ONLY in Hypoxemic patients who are:
• Conscious & have spontaneous respiration
• Who fails to maintain desired Oxygen Saturation despite basic
oxygen therapy support or Have increased work of breathing, &
• Are hemodynamically stable

18. CPAP- Continuous positive airway pressure)
• Aids in oxygenation
• Not much Role in COVID-19 Pneumonia as lungs are stiff
• 1 set pressure (PEEP) throughout the inspiration & expiration
• CPAP Pressure: Adults : 5-10 cm of H2O ( may be increased to 15-20)
• Indications:
• Useful for hypoxemic resp failure, Good option for CHF ( Increases cardiac
output, decreases congestion), Obstructive Sleep Apnea ( Increases FRC),
Neonatal RDS.
• Actions: Recruitment of alveoli (decreases WOB, Increases alveoli available)-
Increases FRC- Increases oxygenation

19. BiPAP (Bilevel positive airway pressure)
Aid in Ventilation (Remove CO2) & Oxygenation ( improve hypoxia)
2 pressures
• IPAP – Inspiratory (12-22 )Action: Support patient breath, help in
Ventilation: Removal of CO2
• EPAP – Expiratory (6-10) Action: Increases FRC, Support
Oxygenation (serves same purpose as CPAP or PEEP in mechanical vent
mode))
Indications: Hypercapnic Resp Failure, COPD
Actions:
1. Pressure Support gradient= IPAP-EPAP
PS supports Vt (Tidal Volume) & thus decreases CO2
2. EPAP- Supports oxygenation

20. Basic BiPAP Setting
•Select option: Spontaneous Timed (ST) Cycle
•IPAP- 12 cm of H2O
•EPAP- 6 cm of H2O
•Ti Max- 1.4 seconds
•Ti Min- 0.2 seconds
•Bpm- 12

21. BiPAP in Context to COVID 19
• COVID 19 results in a restrictive lung disease
• Tidal Volume 4-8 ml/kg
• Limiting inspiratory pressure < 30 cm of H2O
• Permissible Hypercapnia and maintaining pH >7.2
• PEEP levels Titrate
- Low PEEP 5-10 cm of H2O in mild ARDS
- PEEP 10-15 cm of H2O in Moderate to Severe ARDS

22. No Resp acidosis, No Ventilation Problem,
Oxygenation Low- Start CPAP pressure 8-12 and
titrate response

23. Respiratory acidosis, Ventilation Problem, Normal
oxygenation-
Action: Pressures 10/5, EPAP is fine
Increase IPAP to 15 with sane EPAP ( PS: 15-5= 10). This
PS gradient will remove CO2 & correct Resp Acidocis

24. No Ventilation Problem, Decrease Oxygenation
Action: Pressures 15/5, EPAP to be increased to 10
IPAP also need to be increased to 20 to maintain PS of 10
(PS: 20-10= 10). So, revise pressure setting to 20/10. This
will improve oxygenation and maintain same CO2

25. Respiratory acidosis (Ventilation Problem) & Decrease
Oxygenation( Hypoxemic)
Action: Pressures 10/5, Improve PS Gradient & EPAP
Increase IPAP to 20 & EPAP to 10 ( PS: 20-10= 10). This PS
gradient will remove CO2 & correct Resp Acidosis.
Increase EPAP to improve hypoxemia

26. Withdrawal of NIV
• Clinical Improvement
• Aim for
R/R < 24 / min
HR < 110/min
PH ≈7.35
SpO2: 90% on <40% Oxygen

27. Heated Humidified High Flow Nasal Cannula
• Indication: Severe COVID-19 with Type 1 Respiratory Failure
• Delivers optimally humidified and heated O2
• Reduces Work of Breathing
• Improves patient’s compliance & Better Comfort
• Safe
• Decreased body energy expenditure
• Lesser chances of thickened secretions