Modalities of oxygen therapy in picu 31 3-14

Modalities of oxygen therapy in PICU

Dr Suresh Kumar. MBBS, MD, FIAP (PCC), DNB, PGDS, DM (fellow, PCC)31-3-14

Overview

Need of oxygen therapy Oxygen delivery system Oxygen delivery devices Individual oxygen delivery devices and techniques Humidification Complication of oxygen therapy Practical considerations

Joseph Priestley (1775) Heated mercuric oxide and obtained air that caused candles to burn

more brightly Dephlogisticated air (Oxygen)

“From the greater strength and vivacity of the flame of a candle, in the pure air, it may be conjectured, that it might be particularly

salutary to the lungs in certain morbid cases when the common air would not be sufficient though the pure air (oxygen) might be very

useful as a medicine”

Scott Haldane (1860–1936) was first to brought oxygen therapy to a rational and scientific basis

Ubiquitous in modern medicine

Oxygen administration and airway management are two of the fundamental aspects of management in a patient with acute respiratory failure

Proper application of oxygen therapy and airway management are life saving

In the absence of O2 (hypoxia), cellular respiration ceases and irreversible cellular injury and death occur within minutes

Despite the importance of these therapies and their frequent use in the acute care setting, their nuances are often under-appreciated

Oxygen

Colourless, odourless

Medical grade O2 is manufactured by fractional distillation of liquefied air

It is stored as a liquid to reduce the size of the storage container 1 L of liquid O2 produces 860 L of gaseous O2

Most important indication for O2 therapy is to treat hypoxemia The alveolar gas equation illustrates how increasing the

inspired O2 fraction (FIO2) increases the alveolar PO2 (PAO2) and subsequently the arterial PO2 (PaO2)

PAO2 = FIO2(PB-47)-1:25PaCO2

Increasing FIO2, lead to increase in PAO2 In cases of shunt (V/Q=0), supplemental O2 therapy has little

effect on PaO2 If the cause of hypoxemia is low V/Q or diffusion defect,

supplemental O2 therapy will effectively increase the PaO2

PAO2 = 0.21 X 713 - 40/0.8 = 100PAO2 = 0.50 X 713 - 40/0.8 = 306PAO2 = 0.80 X 713 - 40/0.8 = 520

Oxygen therapy

Administration of oxygen at concentration higher than in environment (>21%)

Purpose: Increase oxygen saturation in blood and tissues when it is low due to disease or injury

For oxygen to increase PaO2, there has to be units of low ventilation with normal or near normal perfusion

Any true extra or intrapulmonary R-L shunting will be largely unaffected by increase in alveolar oxygen tension (PAO2)

Oxygen administration by simple tubes and masks to advanced support systems like ECMO

Oxygen therapy in non-intubated children

Goal of oxygen delivery

Maintain targeted SpO2 levels through the provision of supplemental oxygen in a safe and effective way

Relieve hypoxemia and maintain adequate oxygenation of tissues and vital organs

Give oxygen therapy in a way which prevents excessive CO2 accumulation

Reduce the work of breathing Efficient and economical use of oxygen Ensure adequate clearance of secretions and limit the

adverse events of hypothermia and insensible water loss

Oxygen delivery system

Oxygen source

Pressure regulator and flow meter

Oxygen delivery device

Patient

PatientIndications for oxygen delivery

Documented hypoxia/hypoxemia Achieving targeted percentage of oxygen saturation The treatment of an acute or emergency situation where hypoxemia or

hypoxia is suspected, and if the child is in respiratory distress manifested by: Dyspnea, tachypnea, bradypnea, apnea pallor, cyanosis lethargy or restlessness use of accessory muscles: nasal flaring, intercostal or sternal recession, tracheal

tug Circulatory compromise Pulmonary hypertension Short term therapy: post anesthetic or surgical procedure Palliative care: for comfort

Oxygen sources

Medical oxygen can be provided from a

Wall source Provide 50 psi (pounds per square inch ) of pressure

Cylinder Operate at 1800-2400 psi Too much Cannot be directly delivered to patient or run the ventilator Need down regulating valve Flow meter to manipulate the flow rate

Pressure regulator with flow meter

The pressure regulator controls the pressure coming out of the cylinder and is indicated on the gauge in psi

The flow meter controls how rapidly the oxygen flows from the cylinder/wall source to the victim

The flow rate can be set from 1-25 L/min

Oxygen delivery devices

Devices used to administer, regulate, and supplement oxygen to a subject to increase the arterial oxygenation

These system entrains oxygen and/or air to prepare a fixed concentration required for administration

Tubing carries the oxygen from the regulator/flow meter to the delivery device

Oxygen delivery devices…

Classified as:Low-flow or variable-performance devices:Provide oxygen at flow rates that are lower than patients’ inspiratory demandsWhen the total ventilation exceeds the capacity of the oxygen reservoir, room air is entrainedFiO2 delivered depends on the ventilatory demands of the patient, the size of the oxygen reservoir, and the rate at which the reservoir is filledAt a constant flow, the larger the tidal volume, the lower the FiO2 and vice versaFiO2 24-90%

High-flow or fixed-performance devices:Provide a constant FiO2 by delivering the gas at flow rates that exceed the patient’s peak inspiratory flow rate and by using devices that entrain a fixed proportion of room airReliable


Confusion: flow systems with oxygen concentrations

However, both are mutually exclusive in that a high-flow system, viz. Venturi mask, can deliver FiO2 as low as 0.24, whereas a low-flow system like a non rebreathing mask can deliver FiO2 as high as 0.8

If the ventilatory demand of the patient is met completely by the system: high-flow system

if the system fails to meet the ventilatory demand of the patient: low-flow system


A low-flow oxygen delivery system requires that the patient inspire some room air to meet inspiratory demands

Popular: simplicity, patient comfort, and economics FIO2 is determined by the size of the oxygen reservoir, the oxygen

flow rate, and the breathing pattern For example, a nasal cannula at an oxygen flow rate >6 L/min

accomplishes minor increases in FIO2 because the nasopharyngeal reservoir is filled with 100% oxygen at a 6 L/min flow rate

An oxygen reservoir must be increased (placing a mask over the nose and mouth) to achieve an FIO2 greater than 40%

With abnormal ventilatory patterns, the larger the tidal volume, or the faster the respiratory rate, the lower the FIO2


Low flow systems: Nasal cannula Intranasal catheter Simple mask Partial rebreathing

masks Non rebreathing mask

High flow systems: Venturi system Oxyhood Face tent Oxygen tent High flow nasal prongs

CPAP HelioxHyperbaric oxygen


The choice of delivery device: Patient’s oxygen requirement Efficacy of the device Reliability Ease of therapeutic application Humidification needs

Age Patient acceptance and tolerance

Normal flow requirement

3-4 time the minute ventilation (MV = TV X RR)

eg 5 kgs child breathing at rates of 60/min Flow rates needed: 3-4 X (60 X 6 X 5) = 5400-7200

ml/min

Nasal cannula/prongs

Two soft prongs in nostrils attached to the oxygen source Held in place over the patient’s ears Flow is directed to the nasopharynx: humidification and heat

exchange To ensure the patient is able to entrain room air around the

nasal prongs and a complete seal is not created the prong size should be approximately half the diameter of the nares

Available in different sizes Infant Pediatric Adult

Select the appropriate size for the patient's age and size

Nasal cannula/prongs…

Delivers 24-44% FiO2 at flow rate of 1-6 L/min The slower the inspiratory flow the higher the FiO2 A maximum flow of:

2 LPM in infants/children under 2 years of age 4 LPM for children over 2 years of age

With the above flow rates humidification is not usually required

If flow >6 L/min, variable FiO2, need humidification

1 = 24%2 = 28%3 = 32%4 = 36%5 = 40%6 = 44%


Indications Low to moderate oxygen requirement No or mild respiratory distress Long term oxygen therapy

Contraindications Poor efforts, apnea, severe hypoxia Mouth breathing

Advantages Less expensive (Rs 70/-) Comfortable, well tolerated Able to talk and eat

Disadvantages Doesnot deliver high FiO2 Irritation and nasal obstruction Less FiO2 in nasal obstruction FiO2 varies with breathing efforts


Practical considerations: Position the nasal prongs along the patient's cheek and secure

the nasal prongs on the patient's face with adhesive tape Position the tubing over the ears and secure behind the

patient's head Ensure straps and tubing are away from the patient's neck to

prevent risk of airway obstruction Check nasal prong and tubing for patency, kinks or twists at

any point in the tubing and clear or change prongs if necessary Check nares for patency - clear with suction as required Change the adhesive tape frequently as required Check frequently that both prongs are in nostrils

Intranasal catheters

Flexible catheter with holes at distal 2 cms

FiO2 35-40% Measured from nose to ear, lubricated

and inserted to just above the uvula Deep insertion can cause air

swallowing and gastric distension Must be repositioned every 8 hours to

prevent breakdown No advantages over nasal cannula

Simple masks

Made up of clear flexible plastic that can be moulded to fit patients face

Volume: 100-300 mL. FiO2 40-60% at 6-10 L/min Fits person’s face without much

discomfort Perforations, act as exhalation

ports Vents in the mask allow for the

dilution of oxygen

Simple masks…

Indications: Medium flow oxygen desired, mild to moderate respiratory distress When increased oxygen delivery for short period (<12 hrs)

Contraindications: Poor respiratory efforts, apnea, severe hypoxia

Advantage: Less expensive (Rs 80/-) Can be used in mouth breathers

Disadvantage Uncomfortable Require tight seal Donot deliver high FiO2 FiO2 varies with breathing efforts Interfere with eating, drinking, communication Difficult to keep in position for long Skin breakdown

Simple masks…

Practical considerations: Pediatric and adult sizes Select a mask which best fits from the child's bridge of nose to the cleft

of jaw, and adjust the nose clip and head strap to secure in place No pressure point or damage to eyes Flow <4 L/min results in rebreathing and carbon dioxide retention The FiO2 inspired will vary depending on the patient's inspiratory flow,

mask fit/size and patient's respiratory rate Oxygen (via intact upper airway) via a simple face mask at flow rates of

4-6 L/min does not require humidification Humidification may be indicated/appropriate for patients with secretions

retention, or discomfort Some conditions (eg. Asthma), the inhalation of dry gases can compound

bronchoconstriction

Partial rebreathing face masks

Simple masks with additional reservoir that allows the accumulation of the oxygen enriched gas for rebreathing

Allows for the initial portion of the expired gases containing little or no CO2 (rich in oxygen) to be collected in a reservoir while the remaining expiratory gases are vented to the atmosphere

Partial rebreathing face masks…

Fio2 35-60 % flow rates of 6 to 15 L/min

Flow rate must be sufficient to keep bag 1/3 to 1/2 inflated at all times

Minimum flow should be 6 L/min to avoid patient breathing large part of exhaled gases and rest of exhaled air exit through vents

6: 35%8: 45-50%10: 60%12: 60%15: 60%

Partial rebreathing face masks…

Indications: Relatively high FiO2 requirement


Advantage: Inspired gas not mixed with room air Patient can breath room air through exhalation ports if oxygen

supply get interrupted Disadvantage

More oxygen flow doesnot increase FiO2 Interfere with eating and drinking

6: 35%8: 45-50%10: 60%12: 60%15: 60%

Non-rebreathing face masks

Face mask + oxygen reservoir + a valve at exhalation port + a valve between reservoir and mask

Patient inhales oxygen from the bag and exhaled air escapes through flutter valves on the side of the mask

Oxygen flow into the mask is adjusted to prevent the collapse of the reservoir (12 L/min)

It prevent the room air from being entrained 10-15 L/min, FiO2 90-100%

6: 55-60%8: 60-80%

10: 80-90%12: 90%

15: 90-100%

Non-rebreathing face masks…

Indications: High FiO2 requirement >40%


Advantage: Highest possible FiO2 without intubation Suitable for spontaneously breathing patients with severe hypoxia

Disadvantage Expensive (Rs 250/-) Require tight seal, Uncomfortable Interfere with eating and drinking Not suitable for long term use Malfunction can cause CO2 buildup, suffocation

Non-rebreathing face masks…

Practical considerations: To ensure the highest concentration of oxygen is delivered to the

patient the reservoir bag needs to be inflated prior to placing on the patients face

Ensure the flow rate from the wall to the mask is adequate to maintain a fully inflated reservoir bag during the whole respiratory cycle

Do not use with humidification system as this can cause excessive 'rain out' in the reservoir bag

Flow rate must be sufficient to keep bag 1/3 to 1/2 inflated at all times Avoid kinking and twisting of reservoir Check that vales and rubber flaps are working

Venturi masks or Air-entrainment masks

A Venturi mask mixes oxygen with room air, creating high-flow enriched oxygen of a settable concentration

It provides an accurate and constant FiO2 in range of 24-50%

Venturi mask is often employed when the clinician has a concern about CO2 retention

Venturi masks or Air-entrainment masks…

Dilutional masks Work on Bernoulli principle Oxygen is delivered through the jet nozzle, which increases its velocity The high-velocity O2 entrains ambient air into the mask due to the viscous shearing

forces between the gas traveling through the nozzle and the stagnant ambient air FiO2 depends on size of entrainment ports, nozzle, flow rate The larger the port, the more room air is entrained and lower the FiO2 Reliably provide 25-60% FiO2 at 4-15 L/min

3: 24%3: 26%6: 28%6: 30%9: 35%

12: 40%15: 50%


Indications: Desire to deliver exact amount of FiO2

Contraindications Poor respiratory efforts, apnea, severe hypoxia

Advantage: Fine control of FiO2 at fixed flow Fixed, reliable, and precise FiO2 Doesnot dry mucus membranes High flow comes from the air, saving the oxygen cost Can be used for low FiO2 also Helps in deciding whether the oxygen requirement is increasing or

decreasing Disadvantage

Uncomfortable Expensive (Rs 150/-) Cannot deliver high FiO2 Interfere with eating and drinking


Practical considerations: Oxygen must be humidified and warmed Monitor FiO2 at flow rates ordered Not effective for delivering FiO2 greater than 50% To achieve the desired FiO2 use the diagram below Appropriate air entrainment position for desired FiO2 the oxygen flow rate and total flow that will be delivered

to patient when these settings are utilized To ensure that the patient's ventilatory requirements are met the total flow must exceed the patient's minute

ventilation

Oxyhood

Small, clear plastic hood to cover infant’s head or head and upper torso Patient more accessibility without disturbing O2 delivery For newborns and young infants Correct size: That has enough room for baby’s head to fit comfortably and allow free neck and head

movements without hurting baby FiO2 80-90%, Flow 10-15 L/min 3-4 sizes are available; Too big: dilute the oxygen; Too small: discomfort and CO2 retention Adequate flow of humidified oxygen ensures mixing of delivered gases and flushing out CO2 Oxygen gradient can vary as 20% from top to bottom. Continuous flow >6 L/min avoids this problem Ensure the headbox has a gap all around the child’s neck, this is important in preventing the

accumulation and re-breathing of CO2 Gas flow must be high enough to prevent re-breathing of CO2

Face tent/face shield

High flow soft plastic bucket Well tolerated by children than face mask 10-15 L/min, 40% FiO2 Access for suctioning without need for interrupting

oxygen

Oxygen tent

Clear plastic sheet that cover child’s upper body FiO2 50% Not reliable Limit access to patient Not useful in emergency situations

,

Continuous positive airway pressure

By applying underwater expiratory resistance Indicated

When oxygen requirement >60% with a PaO2 of <60 mmHg

Clinical parameters and general conditions also act as guiding criteria

CPAP reduce work of breathing, increases FRC and helps maintain it, recruit alveoli, increase static compliance, and improve ventilation perfusion ratio

Continuous positive airway pressure…

Methods: Underwater (indigenous/bubble ,

commercial) Ventilator

Used in Early ARDS, acute bronchiolitis,

pneumonia It should be tried in spontaneously

breathing child who does not require emergency intubation prior to conventional ventilation

Can be used in early, incipient or frank respiratory failure

Continuous positive airway pressure…

Humidification add to the cost Water vapors condense in tubing

Block Trickle into airways: collapse, pneumonia

Single tube may not be compatible (commercially available binasal prongs)

High flow nasal prongs

Humidified high flow nasal prong (cannula) oxygen therapy is a method for providing oxygen and continuous positive airway pressure (CPAP) to children with respiratory distress

HFNP may reduce need for NCPAP/intubation, or provide support post extubation

At high flow of 2 L/kg/min, using appropriate nasal prongs, a positive distending pressure of 4-8 cmH2O is achieved

This improves FRC and reduces work of breathing Because flows used are high, humidification is necessary to

avoid drying of respiratory secretions and for maintaining nasal cilia function

MOA: application of mild positive airway pressure and lung volume recruitment

High flow nasal prongs…

Indications Respiratory distress from bronchiolitis, pneumonia, congestive heart failure Respiratory support post extubation Weaning therapy from CPAP or BIPAP Respiratory support to children with neuromuscular disease

HFNP can be used if there is hypoxemia and signs of moderate to severe respiratory distress despite standard flow oxygen

Contraindications Blocked nasal passages/coanal atresia Trauma/surgery to nasopharanyx

Complications Gastric distension Pressure areas Pneumothorax


Equipment Oxygen and air source Blender Flow meter

<7Kg : standard 0-15L/min flow meter >7Kg: high flow oxygen flow meter, 50L/min flow

Humidifier (Fisher and Paykel MR850) Circuit tubing to attach to humidifier

Children <12.5kg: small volume circuit tubing Children ≥12.5kg: adult oxygen therapy circuit tubing

Nasal cannula to attach to humidifier circuit tubing (size to fit nares comfortably)

Water bag for humidifier Nasogastric tube


Set up of equipment Appropriate size nasal cannula and circuit tubing Connect nasal cannula to adaptor on circuit tubing,

and connect circuit tubing to humidifier Attach air and oxygen hoses from blender to air

and oxygen supply Connect oxygen tubing from blender to humidifier Attach water bag to humidifier and turn on to 37C


Set up of equipment… Prongs should not totally occlude nares Start the HFNP at the following settings:

Flow rate ≤10Kg 2 L/kg/min >10Kg 2 L/kg/min for the first 10kg + 0.5L/kg/min for each kg above

that (max flow 50 L/min) Start off at 6L/min and increase up to goal flow rate over a few minutes to

allow patient to adjust to high flow

FiO2 Always use a blender, never use flow meter off wall delivering FiO2 100% Start at 50-60% for bronchiolitis and respiratory distress


HFNP Improves the respiratory scale score Oxygen saturation Patient's COMFORT scale Reduce need for mechanical ventilation

Children with respiratory distress treated with high-flow nasal cannula. J Inten Care Med 2009High-flow nasal cannula oxygen therapy for infants with bronchiolitis: Pilot study.J Paediatr Child Health. 2014High-flow nasal cannula (HFNC) support in interhospital transport of critically ill childrenIntensive care med 2014High-flow nasal prong oxygen therapy or nasopharyngeal continuous positive airway pressure for children with moderate-to-severe respiratory distress? Pediatr Crit Care, 2013High-flow nasal cannula therapy for respiratory support in children. Cochrane Database Syst Rev.2014 Mar 7;3:CD009850Reduced intubation rates for infants after introduction of high-flow nasal prong oxygen delivery. Intensive Care Medicine. 2011

Hyperbaric oxygen

The goal is to deliver extremely high partial pressure of oxygen, >760 mmHg Indications:

Smoke inhalation CO poisoning CN poisoning Thermal burns Air embolism Clostridium myenecrosis Osteomyelitis (refractory) Compromised skin grafts Radiation injury Acute traumatic ischemia/acute crush injury Severe decompression sickness Necrotizing fasciitis

Hyperbaric oxygen

Requires specialized equipment and personnel with intensive care unit skills and knowledge of the physiology and risks unique to hyperbaric oxygen exposure (CNS and Pulmonary)

Cost, unavailability

Hyperbaric oxygen…

The half-life of COHb is about five hours breathing 21% O2 at ambient pressure, a little more than one hour breathing 100% O2 at ambient pressure, and 30 min breathing 100% O2 at 3 atm of pressure

Heliox

Heliox is a gas mixture of helium and oxygen: low density

Obstructive lung diseases (bronchiolitis, acute bronchial asthma) In spontaneously breathing patients with asthma, heliox decreases

PaCO2, increases peak flow, and decreases pulsus paradoxus There may be benefit related to the combination of heliox with

aerosol bronchodilator delivery in patients with acute asthma

Heliox reduce resistance with upper airway obstruction (post extubation stridor)

Heliox…

Care must be taken to administer heliox in a safe and effective manner

To avoid administration of a hypoxic gas mixture, it is recommended that 20% oxygen/80% helium is mixed with oxygen to provide the desired helium concentration and FIO2

If an FIO2 requirement >40%, the limited concentration of helium is unlikely to produce clinical benefit

When using an oxygen-calibrated flow meter for heliox therapy, it must be remembered that the flow of heliox (80% helium and 20% oxygen) will be 1.8 times greater than the indicated flow

Heliox…

For spontaneously breathing patients, heliox is administered by face mask with a reservoir bag

Y-piece attached to the mask allows concurrent delivery of aerosolized medications

Sufficient flow is required to minimize contamination of the heliox with ambient air: 12 to 15 L/min

Administration during mechanical ventilation can be problematicDensity, viscosity, and thermal conductivity of helium affect the delivered tidal volume and the measurement of exhaled tidal volume

Measurement of delivered oxygen

Oxygen analyser or FiO2 meter Sensor digitally convert sensed

concentration into reading Quality and accuracy of sensor is most

important Expensive part Calibration with every use The oxyhood is ideal place, can be used

within masks held at moth or nose

Monitoring

Oxygen should not be administered without an objective assessment of its effect

Oxygen therapy should be used without wasting time and thought Further therapy, amount, duration can then be formulated FiO2 of 40-60% is adequate in most situations, 100% needed during

resuscitation Increasing requirement of FiO2 to maintain same SpO2 is an omniuos

sign Children should be nursed in manner that makes them most comfortable Mothers can be the best administrator of the oxygen A frightened and agitated mother result into frightened and agitated

child Spend some time to explain the situation

Monitoring…

Vital signs (hourly) HR RR (including level of distress) BP Temperature SpO2

Breathing pattern Level of consciousness and responsiveness Color ABG

SpO2 >92% and PaO2 > 60 mmHg are acceptable

Monitoring…

Check and document oxygen equipment set up at the commencement of each shift and with any change in patient condition

Hourly checks should be made for the following: oxygen flow rate patency of tubing humidifier settings (if being used)

Monitoring…

Document Day and time oxygen started Method of delivery Oxygen concentration and flow Patient observation Oronasal care and nursing plan

Oxygen is a drug and requires a medical order Each episode of oxygen delivery should be ordered on

the medication chart

Humidification

Humidification: Addition of heat and moisture to a gas Rationale:

Cold, dry air increases heat and fluid loss Medical gases including air and oxygen have a drying effect on mucous

membranes resulting in airway damage Secretions can become thick & difficult to clear or cause airway obstruction In some conditions e.g. asthma, the hyperventilation of dry gases can

compound bronchoconstriction Indications:

Patients with thick copious secretions Non-invasive and invasive ventilation Nasal prong flow rates of greater than 2 L/min (<2 years) or 4 L/min (>2 years) Facial mask flow rates of greater than 5 L/min All high flow systems require humidification Patients with tracheostomy

Humidification…

Fisher & Paykel MR 850 Humidifier Invasive Mode: Delivers saturated gas as

close to body temperature (37 degrees, 44mg/L) as possible. Suitable for patients with:

Nasal Prongs Invasive Ventilation Tracheostomy attachment or mask

Non-Invasive Mode: Delivers gas at a comfortable level of humidity (31-36 degrees, >10mg/L). Suitable for patients receiving:

Face mask therapy Non-invasive ventilation (CPAP/BIPAP)

Humidification…

Humidifier should always be placed at a level below the patient's head

Water levels of all humidifiers should be maintained as marked to ensure maximum humidity output

Condensation will occur in the tubing of heated humidifiers. This water should be discarded in a trash contain and never returned into the humidifier

Inspired gas temperature should be monitored continuously with an inline thermometer when using heated humidifiers

The thermometer should be as close to the patient as possible Warm, moist areas such as those within heated humidifiers are

breeding grounds for microorganisms (especially Pseumomonas) The humidifier should be changed every 24 hours

Weaning

Depend on clinical and lab parameters SpO2 is important High flow and concentration should be gradually

lowered while monitoring Low flow and concentration can be continued

without ill effects for long time

Adverse effects

Oxygen being combustible, fire hazard and tank explosion Catheters and masks can cause injury to the nose and

mouth Dry and non-humidified gas can cause dryness and crusting Long term oxygen therapy: proliferative and fibrotic changes

lungs In acute conditions, high FiO2 lead to the release of various

reactive species which attack the DNA, lipids, and SH containing proteins

Infections

Adverse effects… CO2 Narcosis :

In patients with chronic respiratory insufficiency----hypercapnea Respiratory centre relies on hypoxemia to maintain adequate ventilation Oxygen supplementation can reduce their respiratory drive, causing

respiratory depression and a further rise in PaCO2 resulting in increased CO2 levels in the blood

Monitoring of SpO2 or SaO2 informs of oxygenation only. Therefore, beware of the use of high FiO2 in the presence of reduced minute ventilation

Pulmonary Atelectasis/absorption atelectasis Pulmonary oxygen toxicity : High concentrations of oxygen (>60%) may

damage the alveolar membrane when inhaled for >48 hours resulting in pathological lung changes

Retrolental fibroplasia: An alteration of the normal retinal vascular development, mainly affecting premature neonates (<32 weeks gestation or 1250g birthweight), visual impairment and blindness

Adverse effects…

Signs and symptoms of oxygen toxicity Nonproductive cough Nausea, vomiting Substernal chest pain Fatigue Nasal stuffiness Headache Sore throat Hypoventilation Nasal congestion Dyspnea

Low concentration oxygen therapy

Reserved for children at risk of hypercapnic respiratory failure Advanced cystic fibrosis and non cystic fibrosis brochiectasis Severe kyphoscoliosis or severe ankylosing spondylitis Severe lung scarring caused by TB Musculoskeletal disorders with respiratory weakness Overdose of opioids, benzodiazepines, or other drugs causing

respiratory depression. Uncorrected cardiac defects.

Until blood gases can be measured, initial oxygen should be given using a concentration of 28% or less, titrated towards a SpO2 of 88-92%

Oxygen safety

Oxygen support combustion (rapid burning). Due to this the following rules should be followed: Do not smoke in the vicinity of oxygen equipment Do not use aerosol sprays in the same room as the oxygen

equipment Turn off oxygen immediately when not in use. Oxygen is heavier

than air and will pool in fabric making the material more flammable. Therefore, never leave the nasal prongs or mask under or on bed coverings or cushions whilst the oxygen is being supplied

Do not use any petroleum products or petroleum byproducts e.g. petroleum jelly/Vaseline whilst using oxygen

Do not defibrillate someone when oxygen is free-flowing

Oxygen safety…

Oxygen cylinders should be secured safely to avoid injury and damage to regulator or valve

Do not store oxygen cylinders in hot place Do not drag or roll cylinders Do not carry a cylinder by the valve or regulator Do not hold on to protective valve caps or guards when moving or lifting

cylinders Do not deface, alter or remove any labeling or markings on the oxygen

cylinder Do not attempt to mix gases in an oxygen cylinder or transfer oxygen from

one cylinder to another

Take home message

Oxygen therapy saves life The selection of an appropriate oxygen delivery system

Clinical condition Patient's size and needs Therapeutic goals

Risks and hazards Advantages far outweighs the risks Hypoxia more dangerous than correctly delivered oxygen

Humidification Monitoring and proper documentation Donot forget to taper oxygen Use but do not abuse oxygen

References

http://www.rch.org.au/rchcpg/hospital_clinical_guideline_index/Oxygen_delivery/

Bateman, N.T. & Leach, R.M. (1998). ABC of Oxygen - Acute oxygen therapy. BMJ, September 19; 317(7161): 798-801.

Ricard, J. & Boyer, A. "Humidification during oxygen therapy and non-invasive ventilation: do we need some and how much"? Intensive Care Med (2009) 35: 963-965

Oxygen Therapy: Important Considerations. Indian J Chest Dis Allied Sci 2008; 50: 97-107

http://www.rch.org.au/rchcpg/hospital_clinical_guideline_index/Oxygen_delivery/

THANK YOU

Modalities of oxygen therapy in picu 31 3-14

Health & Medicine