oxygen delivery devices

Essentials course in EMEssentials course in EM hospital-based

Emergency care:

1. Pre-hospital EMS

2. Hospital-based.

3. Disaster management

To Oxyen DevicesTo Oxyen DevicesBy Dr. Fekri Eltahir Abdalla

Oxygen Delivery Devices

By Dr. Fekri Eltahir Abdalla

Oxygen Delivery Systems


Types of hypoxia

Types Definintion Typical cases

Hypoxic oxygen tension High altitude – hypoventilation – V/Q mismatch.

Anemic carrying capacity Anemia – blood loss – CO poisoning

Stagnant perfusion Heart failure – Shock – ischemia

Histotoxic Cellular hypoxia Cyanide – other metabolic poisons – shifting of O2-HB curve.


Oxygen dissociation curveOxygen dissociation curve


Decreased Temp.Decreased 2,3 DPGDecreased {H+}

Increased Temp.Increased 2,3 DPGIncreased {H+}

Grading of hypoxia


Respiratory failure

How to manage Hypoxia


LOCResp. effortChest exam

Oxygen dose


Device characteristics

Device Mask Reservoir Total storage

Nasal prongs No 50 ml (DS) 50 ml

Simple mask 100 – 200 ml 50 ml (DS) 150 – 250 ml

Mask reservoir 100 – 200 ml 650 – 1050 ml 750 – 1250 ml

Venturi mask 100 – 200 ml 50 ml (DS) 150 – 250 ml

DS = dead space = air in the hypopharynx.Mask reservoir = partial rebreathing & non-rebreathing masks.


Patient demand


Hypoxia

Respiratory Failure


Type 2 (Hypercapnic RF)Type 1 (Hypoxemic RF)

PaO2 < 60 mmHgPaCO2 ( low or normal)

PaO2 < 60 mmHgPaCO2 > 45 mmHg

COPD patient with PaCO2 of 60 mmHg, PaO2 of 61 mmHg and pH 7.37. Is there any RF? Which type?

ABGNot

Oximeter

PaO2-FiO2 ratio

Normal PaO2/FiO2 is 300-500 <200 indicates a clinically significant gas

exchange derangement Ratio often used clinically in ICU setting


Oxygen Devices ClassificationOxygen Devices Classification


Nasal Prongs


Nasal Prongs

Advantages Disadvantages

Tolerable (satisfaction + compliance) Flow limitation.?

Can use the mouth (eat, speak, treat) FiO2 limitation.?

Avoid high FiO2 in COPD. Nasal drying and irritation with high flow rate?


Case 1:

A young female presented with dry cough, fever and SOB. She was found hypoxic at the triage (Sat 87%). The nurse put her in oxygen using nasal prong at flow of 4 L/min. She improve a little pit to 91% saturation. What your next best action to improve her oxygenation?

A. Shift her to simple mask at 5 L/min.

B. Shift her to non-rebreathing mask at 5 L/min

C. Increase the nasal prong flow to 5 L/min

D. No need to make any change.


Simple mask

Characteristics Advantages Disadvantages

Flow not < 5 L/ minCO2 retention

Higher FiO2 compared to nasal prong

Loose = air leak, mixed room air (lower FiO2)

Loosely fitted to the faceAir leak – mixed room air

Can use nebulizer. Can not use the mouth to eat, drink, speak

Max flow rate = 10 L/ minFiO2 = 40 – 60 %Approx = 4%/L/min

Can use venture. Limited FiO2 (Max 60%)Pt demand not met in some cases.

No reservoir bagStorage ?


Case 1 continued

As the patient had oxygen flow rate of 5 L/ min, her saturation reached 93% for 15 min then she dropped again to 89%. The nurse increased the flow to 6 L/min using nasal prong but the saturation became 90% for 5 minutes. You decided to shift to simple mask. What is the best flow rate to start with? And why?

A. Simple mask at 5 L/min

B. Simple mask at 6 L/ min

C. Simple mask at 7 L/min

D. Simple mask at 10 L/min


Case 2

A known asthmatic young man resented with acute SOB and he was found tachypneic (RR=35), tachycardic (HR = 120) and desaturated (SPO2 = 88%). You found diffuse wheeze at auscultation with decreased air entry bilaterally. You planned to give him oxygen plus nebulized Ventolin initially, but he still continued desating while on oxygen-powered nebulized therapy. Your best action of management then is:

A. Shift to non rebreathing mask and continue nebulization.

B. Intubate the patient immediately for acute severe asthma.

C. Initiate non invasive mechanical ventilation and delay Ventolin therapy.

D. Put him on nasal prong plus continue nebulized Ventolin with simple mask at maximum flow rate.


Mask plus reservoir


Simple mask

Partial rebreathing mask

Non rebreathing mask

The device Characteristics Advantages Disadvantages

Simple mask5 – 10 L/minFiO2 ( 40 – 60%)

Mask – no reservoir

Nebulizer or venture portAccepted FiO2

Considerable air mixing -No use of mouth

Partial mask5 to max toKeep bag inflated

Simple mask + reservoir

Higher FiO2FiO2 (up to 80 %)

Less room air mixing - no use of nebulizer or venturi

Non rebreathing5 to max to keep bag inflated

Simple mask + reservoir + one way valve

Highest FiO2Negligible room air mixingFiO2 (up to 95%)

No use of mouth, venture or nebulizer


Partial rebreathing/ non rebreathing

Case 3

A known COPD patient on home oxygen (2 L per nasal prong) presented with acute exacerbation. At triage was found tachypneic and desat (SPO2 75%). The nurse started 4L O2 by nasal prong and you add non oxygen power nebulized Ventolin. After 20 min, saturation became 82%. You plan to continue nebulization plus requesting ABG. What is the best O2 delivery device for this patient at this level (ABG pending!)?

A. Simple mask at 5 L/min

B. Adjustable venture mask.

C. CPAP

D. Intubation and mechanical ventilation


Venturi mask

Characteristics Advantages Disadvantages

High flow device Controlled FiO2 Limited low FiO2

Room air mixing Suitable for chronic CO2 retention

Ignores patient O2 demand

Adjustable valve Can use nebulizer

Use simple mask or CPAP


Venturi mask


Positive pressure ventilation

Indications Advantages Disadvantages

Hypoxia despite full O2HypoventilationCO2 retention

Decrease work of breathing

Unprotected airway

Avoid intubation Gastric insufflation

Requirements Improve oxygenation Slow correction (time)

Conscious – cooperative – vitally stable – airway protected by their own – reversible cause

Improve ventilation Tight mask problems

Decrease venous return


NIV Monitoring

ResponsePhysiological a) Continuous oximetry

b) Exhaled tidal volume c) ABG should be obtained with 1 hour and, as

necessary, at 2 to 6 hour intervals.Objective a) Respiratory rate

b) blood pressure c) pulse rate

Subjective a) dyspnea b) comfort c) mental alertness


NIV Monitoring

MaskFit, Comfort, Air leak, Secretions, Skin necrosis

Respiratory muscle unloadingAccessory muscle activity, paradoxical abdominal motion

AbdomenGastric distension


NIV Discontinue

Inability to tolerate the mask because of discomfort or pain

Inability to improve gas exchange or dyspnea Need for endotracheal intubation to manage

secretions or protect airway Hemodynamic instability ECG – ischemia/arrhythmia Failure to improve mental status in those with CO2

narcosis.




Less dead space.ClaustrophobiaCan use mouth

Dyspnic are mouth breather.More dead space.Clustrophobia



Method of NIV CPAP BiPAP

Name Continuous Positive Airway Pressure

Bilevel Positive Airway Pressure

Descriptions Preset ePAP (PEEP)Pt initiate breathingePAP ( 4 to 20 cmH2O)Open more alveoli (recruitment)

Preset iPAP/ ePAPPt initiate breathingCan set backup RRiPAP (8 – 20 cmH2O)ePAP (4 – 10 cm H2O)

Indications COPD – APE(decrease venous return) – sleep apnea

Acute hypercapnia – cardiogenic APE – resp muscle fatigue/paralysis

Indications Advantages Disadvantages

Severe hypoventilation RR < 8/ min

Simple technique (learning)

Uncontrolled hyperventilationGastric – lung - ABG

Apnea Available Temporary

Cardiac arrest Positive pressure/ PEEPAssist ventilation/O2

MOANS/ open airwayEffectiveness?

Preoxygenation in RSI High FiO2 100% Utilize medical personnel



Case 4

While you are treating COPD patient with venturi mask plus nebulized SABA, he is not improving and continued desating after 1 hour of your management and his ABG showed (pH 7.20, pCO2 65 mmHg, pO2 50 mmHg). His vital signs: HR 125, RR 36, BP 85/54, GCS 14/15. what is your best next action of management?

A. Shift to CPAP immediately.

B. Shift to BiPAP immediately.

C. Intubation and mechanical ventilation.

D. Give IV fluids and continue same plan.


Summary

O2 is a drug, so it must be used judiciously. You should set your targets: Before you move to mechanical ventilation, consider to make the

maximum use of simple devices available. It is important to keep in mind each device capabilities and

limitations. Monitoring during O2 therapy is vital. NIV is an option but patient should meet the criteria for its

application.


Before The end


Questions?


oxygen delivery devices

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