OXYGEN DELIVERY DEVICES

Presenter : Dr Adil FarooqModerator: Dr Renuka HShri B.M. Patil Medical College Hospital and Research Center, VIJAYAPUR, KARNATAKA

Introduction: Oxygen is one of the most important drugs you will ever use,

but it is poorly prescribed by medical staff. In 2000, Nicola Cooper and colleague did survey of treatment

with oxygen. They first looked at prescriptions of oxygen in postoperative

patients in a large district hospital. They found that there were many ways used to prescribe oxygen and that the prescriptions were rarely followed.

1. Documented hypoxemiaIn adults, children, and infants older than 28

days, arterial oxygen tension (PaO2) of < 60 mmHg or arterial oxygen saturation (SaO2) of < 90% in subjects breathing room air.

In neonates, PaO2 < 50 mmHg or SaO2< 88% or capillary oxygen tension (PcO2)< 40 mmHg

Indications of O2 therapy

2 . An acute care situation in which hypoxemia is suspected.

3. Severe trauma.4. Acute myocardial infarction.5. Routine surgery6. Short-term therapy (e.g., post-anesthesia recovery)7. Anxiety8. During Childbirth9. Increased metabolic demands, i.e. burns, multiple

injuries, and severe infections.

Three clinical goals of O2 therapy

1. Treat hypoxemia

2. Decrease work of breathing (WOB)

3. Decrease myocardial Work

Need is determined by measurement of inadequate oxygen tensions or saturations, by invasive or noninvasive methods, or the presence of clinical indicators as previously described.

Arterial blood gases Pulse oximetry Clinical presentation

Assessment of need

FACTORS THAT DETERMINE WHICH SYSTEM TO USE

1. Patient comfort / acceptance by the Patient 2. The level of FiO2 that is needed

3. The requirement that the FiO2 be controlled within a certain range4. The level of humidification and nebulization5. Minimal resistance to breathing6. Efficient & economical use of oxygen

Based on performance of deviceA. Fixed performance -Venturi maskB. Variable performance -Nasal prongs,

Face mask Based on Flow delivered by deviceA. High flow - Venturi maskB. Low flow -Nasal prongs,

Face mask, Partial and Non

Rebreathing bag,

Tracheostomy mask.

Classification:

Based on Patient:Patient Dependent -Face mask

Nasal prongs Nasopharyngeal

catheters CPAP

Patient independent -Ventilators

Based on degree of dependency:Low dependency -Face mask, Nasal prongsMedium dependency -CPAPHigh Dependency -Non Invasive and Invasive

Positive pressure Ventilation

Oxygen is provided at a certain flow rate in L/minute.

The patient’s rate and depth of breathing determines the FiO2 and is mostly not fixed at a fixed flow rate.

i.e Fast and deep breathing results into lower FiO2 because it draw more room air into lungs and thus dilutes the inspiratory gas and oxygen concentration.

LOW-FLOW (VARIABLE FiO2) DEVICES

Variable performance, low flow device with no capacity.

A flow rate of 0–6 L/minute can be used with nasal cannula depending upon the size of patient and requirement of oxygen.

At flow rate of more than 6 L/minute does not help in improving oxygenation and of no use.

Above a flow rate of 4 L/minute (without humidification) there is increased chance of nasal irritation

In neonates and infants (flow rate 0.025–1.0 L/minute). Nasal cannula can be considered a high-flow device for infants and neonates because inspiratory flow rate for infants and neonates is very low.

Nasal cannula

Nasal cannulaFio2 ranges from 24-40% of O2 at 1-5ltr of O2

1 - 24% 2 - 28%

3 - 32%4 - 36%5 - 40%

Advantages Disadvantages Inexpensive Pressure sores well tolerated, comfortable Crusting of secretions easy to eat, drink,speak Drying of mucosa used in pt with COPD Epistaxis

Variable performance, low flow device with no capacity.

Catheter size 8-14 FG Catheter should be well lubricated prior to insertion. Depth of insertion should be equal to the distance from

Alae Nasi to the Tragus.DisadvantagesNot commonly used because Hygenic care is difficult Skin irritation Pain in the frontal sinus

Nasopharyngeal Catheter

Low flow, variable performance, small capacity device.

The placing of mask over the patient’s face increases the size of the oxygen reservoir beyond the limits of the anatomic reservoir ;therefore a higher FiO2 can be delivered.

The oxygen flow must be run at a sufficient rate, usually 4 ltr/min or more to prevent rebreathing of exhaled gases.

Simple face mask (Hudson’s mask)

Oxygen is delivered through a 7 mm diameter oxygen tubing from oxygen source.

This is most commonly used in post-anesthesia care units in patients recovering from anesthesia.

This is always recommended for short-term use in patients with chronic lung disease for acute hypoxic breathlessness.

O2 flow rate(ltr/min) FiO2 5-6 40% 6-7 50% 7-8 60%

It should be better used with some humidification device if planned for prolonged use or used in pediatric or neonatal patients.

Advantages: simple, lightweight, FiO2 upto 60%, can be used with humidity

Disadvantages: need to remove when speak, eat, drink, vomiting, expectoration of secretions, drying / irritation of eyes, uncomfortable when facial burns / trauma application problem when RT in situ

Low flow, variable, medium capacity device. It is connected to a nebulizer It delivers water/drug in Aerosol form. Max FiO2 estimated is 50%

Aerosol (Nebulizer) Face mask

Partial rebreathing mask• High oxygen , Low flow, variable

performance Device• FLOW 6-10 L/min can provide 40-70%

O2• Bag should be half to 1/3rd full on

inspiration

Advantages:exhaled oxygen from anatomic dead space is conserved.

Disadvantages: insufficient flow rate may lead to rebreathing of CO2, claustrophobia; drying and irritation of eyes

Features: unidirectional valve system to

prevent mixing of expired gases and fresh gas flow.

Fio2 60-80% with 10L/min. High flow to prevent rebreathingDisadvantage:Humidification system is not used so

long term oxygenation causes nasal and oral mucosal irritation.

Non-rebreathing bag

Low flow, variable performance, low capacity device. These are same as simple face

mask used at tracheostomy site in patients with permanent or temporary tracheostomy.

Tracheostomy Mask/Collar

The minimum flow rate required as in facemask is 3–4 L/minute to prevent expired gas rebreathing, carbon dioxide accumulation.

The delivered FiO2 is highly variable based on the patient’s inspiratory flow, fitting of mask and patient’s respiratory rate and pattern.

A ‘Swedish nose’ device for supplying supplemental oxygen on a long-term basis via a tracheostomy tube.

High-flow or fixed performance oxygen therapy devices provide oxygen at a certain concentration or FiO2.

With a properly functioning device and proper set up of device, fixed or pre determined FiO2 is always available to the patient.

If patient’s inspiratory demand exceeds the output of this device, it can no longer be classified as “high-flow” and FiO2 will decrease.

HIGH-FLOW (FIXED FiO2) DEVICES

A Venturi is a simple design of valve that uses high-flow oxygen supplied through a narrow port which allows room air to be drawn in from atmosphere

The rate of flow generated by this Venturi mask may be equal to peak inspiratory flow of patient.

There are coloured dilutor jets which deliver a particular FiO2 (24–50% depending upon the use of dilutor jet) at a particular flow rate set.

Venturi mask (Air Entrainment Mask )

Venturi Mask is most commonly used for chronic obstructive pulmonary disease patients requiring a specific FiO2 that will not fluctuate with changes in breathing pattern

And also may be used in patient during weaning from long-term oxygen therapy to gradually lower the FiO2.

Long-term and high-flow dilutor mostly need humidification device to be used.

HAFOE- this system is also called as High airflow with oxygen enrithment.

The Bernoulli effect and the Venturi principle

• The Bernoulli effect describes the change in pressure that occurs when a fluid flows through a constriction.

• The Venturi principle uses this phenomenon to allow a second fluid to be entrained into the stream of the first, either through a side arm that opens into the area of low pressure or via a co-axial arrangement

VENTURI VALVE

Venturi valve Color FiO2 O2 Flow

Blue 24% 2 L/minWhite 28% 4 L/min

Orange 31% 6 L/minYellow 35% 8 L/min

Red 40% 10 L/minGreen 60% 15 L/min

Multi-vent Venturi mask is an adjustable Venturi mask, in which, in same mask it is possible to use different flow rate and desired FiO2 for changing oxygen requirement.

It has color coded air-entrainment

Multi-Vent Masks

The amount of FiO2 provided by this is almost 100% (no oxygen dilution) and patients requiring this amount of oxygen are generally having critical oxygenation problems and they should be either in intensive care units or high dependency units.

High-Flow High FiO2 Nebulizer (Misty-Ox®)

Face tent Mask

• The face tent mask provides oxygen to the nose and mouth without the discomfort of a mask.

• It has an added. advantage to be used for patients with facial trauma or burns.

•  A face tent delivers oxygen concentrations of 28% to 100% with flow rates from 8 to 12 L/min.

A t-tube is a t-shaped device with a piece that connects the oxygen source to the artificial airway (endotracheal tube or tracheostomy).

The recommended flow rate when using a t-tube is 10 L/min, with a nebulizer set at the appropriate oxygen concentration.

T tube

Transtracheal oxygenTranstracheal Oxygen Delivery•Can be used in long term Oxygen Therapy in COPD patients.•Sleep Apnoea Syndrome.•Cosmetically Accepted.

Oxygen hood Aerodynamic design allows

consistent and even flow of oxygen to baby.

Maintains stable temperature. Fully transparent allows clear

view of baby. Oxygen concentrations of 80 to

90% can be achieved with oxygen flow rates of 10 to 15 L/min

Pediatric oxygen delivery system

Oxygen hood Oxygen enters the

hood through a gas inlet.

Exhaled gas exits through the opening at the neck.

Oxygen tent• An oxygen tent is a bendable

piece of clear plastic held over child's bed or crib by a frame.

• The plastic is then tucked under the mattress.

• Child can move around on his bed without having to wear an oxygen mask

•  humidity helps prevent the loss of water from child's body as he breathes.

Pediatric oxygen delivery Summary

Oxygen-induced hypoventilation Oxygen toxicity/O2 narcosis Absorption atelectasis Retinopathy Drying of mucous membranes Infection Fire hazards

Hazards & complications of oxygen therapy

Nasal cannulae and nasopharyngeal catheters are used to provide low level supplemental oxygen. They are also used to supplement oxygen in patients who are being fed so that there is no interruption in oxygen supplementation.

Simple oxygen masks are used to provide supplemental oxygen in the moderate range (0.35 to 0.50, depending on size and minute ventilation) for short periods of time (e.g., during procedures, for transport, in emergency situations).

Summary:

Air-entrainment nebulizers, can be used when high levels of humidity or aerosol are desired.

Partial rebreathing masks are used to conserve the oxygen supply when higher concentrations (FiO2 > 0.4, < 0.6) are warranted (e.g. during transport).

Non-rebreathing masks are used to deliver concentrations > 0.60.

Venturi masks are used when precise FiO2 has to be delivered e.g. COPD.

Summary:

Davey AJ, Diba A. Ward’s Anaesthetic equipment.

Dorsch J A, Dorsch SE. Understanding Anesthesia Equipment .

Tata Memorial; Objective Anesthesia Review. Baheti; Understanding Anesthetic

Equipment & Procedures A Practical Approach.

References: