Techniques of Oxygen DeliveryDr. Sunil Agrawal1st yr MD Pediatrics
Contents• Requirement of supplemental oxygen• Different types of flow systems• Devices used for oxygen delivery• Technique to delivery oxygen• Adjuncts to Oxygen Delivery• Summary• References
• Patient conditions that warrant administration of Supplementaloxygen:– Difficulty breathing– Respiratory compromise due to any cause– Circulatory compromise– Shock– Decreased level of consciousness– SpO2 of less then 96%
• Oxygen delivery system can be divided into– Low flow systems– High flow systems
Low Flow System• In this the room air is entrained because the gasflow is insufficient to meet all inspiratory flowrequirements.• Provide an oxygen concentration of 23% to 90 %• Not so reliable
High Flow Systems• The flow rate and reservoir capacity provideadequate gas flow to meet the total inspiredflow requirements of the patient.• Entrainedment of the room air does not occur.• Provide low or high inspired oxygenconcentration.• Reliable
Oxygen mask• Simple oxygen mask-– low flow device– Deliver 35% to 60% oxygen with flow rate of 6 to 10 L/ min– Minimum oxygen flow of 6L/min should be used– Indications: Medium flow O2 desired- mild to mod. Respdistress– Contra indication: Poor resp. effort, Severe hypoxia, Apnea– Advantage: less expensive– Disadvantage : does not deliver high conc. O2 , Interfereswith eating and talking.
• Partial rebreathing mask– Simple face mask + reservoir bag– Reliable to provide oxygen concentration of 50% to 60%– Oxygen flow of 10 to 12 L/min is generally required– Indications: relatively high O2 requirement .– Contra indication: Poor resp. effort, Severe hypoxia, Apnea– Advantage: inspired gas not mixed with room air– Disadvantage : more O2 flow does not increase O2 conc,Interferes with eating and talking.
• Non breathing mask– Face mask + reservoir bag+• A valve incorporated into the exhalation port• A valve placed between reservoir bag and mask– Oxygen flow into the mask is adjusted to prevent collapse of bag– Inspired concentration of oxygen of 95% can be achieved by 10to 12L/min of oxygen– Well sealed face mask is used– Indications: delivery of high conc. Of O2– Contra indication: Poor resp. effort, Apnea– Advantage: high conc. O2 without intubation– Disadvantage : expensive, more O2 required. Interferes witheating and talking. Requires a tight seal.
• Venturi- type mask– Reliable– Provide controlled low to moderate (25% to 60%)of inspired oxygen concentration– Indications: desire to deliver exact amount of O2– Contra indication: Poor resp. effort, Severehypoxia, Apnea– Advantage: fine control of FIO2 at a constant flow– Disadvantage : expensive, can not deliver high O2conc. Interferes with eating and talking
Face tent• Also known as face shield• High flow soft plastic bucket• Well tolerated by children then face mask• Up to 40% of oxygen can be delivered with 10to 15 L/min of oxygen flow• Access for suctioning is achieved withoutinterrupting the oxygen flow.
Oxygen tent• Clear plastic shell that encloses the child’supper body• Provide more then 50% of O2• Not reliable• Limits access to patient• Cannot be used in emergency situation.
Nasal Cannula• Low flow oxygen device• Consist of 2 short soft plastic prongs which are insertedin to the ant. Nares and O2 is delivered into thenasopharynx• Upto 4 L/min of O2 can be used• Does not provide humidified oxygen– Indications: low to mod O2 required, mild or no distress, longterm O2 therapy requirement.– Contra indication: Poor resp. effort, Apnea, severe hypoxia,mouth breathing.– Advantage: comfortable, well tolerated.– Disadvantage : does not deliver high O2 conc.
Nasal catheter• Flexible, lubricated oxygen catheter withmultiple holes in distal 2 cm• Advanced posteriorly into the pharynxthrough nostril• No advantage over nasal cannula• Hemorrhage and gastric distension can occur
Oxygen hood• Clear plastic shell with covers the patient’s head• Well tolerated by infants• Allows access to chest, trunk and extremities• Permits control of inspired oxygen concentration,temp. and humidity• Flow of oxygen- 10-15 L/min• 80 to 90 % of oxygen conc. can be achieved• Can be used in neonates and infants only.
Bag Valve Mask Ventilation• Two hands must be used– One hand- head tilt- chin lift maneuver– Other hand- compress ventilation bag• In infants and toddlers, the jaw is supportedwith base of middle and ring finger. Pressurein submental area should be avoided• In older children finger tips of 3rd, 4th, 5thfingers are placed on the ramus of mandibleto hold the jaw forward and extend head.
• A neutral sniffing position is maintained.• Hyperextension of head is avoided to maintainthe optimum position for airway patency.• This can be achieved by placing folded towelunder the neck and head.• Distention of stomach frequently occurs. It shouldbe avoided or treated promptly to preventaspiration. It can be minimized in unconsciouspatient by applying cricoid pressure (Sellickmaneuver)
Self inflating Bag-Valve Ventilation Devices• At oxygen inflow of 10L/min, pediatric self inflating bagprovides 30-80% of oxygen without oxygen reservoir and60-95% with reservoir.• 10-15L/min of oxygen is required to keep the adequateamount of oxygen in reservoir.• Before initiating ventilation oxygen flowing into the bagshould be confirmed.• Many bags have a pop off valve set as 35 to 45 cm of H2O toprevent barotrauma.• During CPR a high pressure is required so pop off valveshould be closed.
• Administered tidal volume should be approx. 10-15 ml/kg.• About 450ml of bag should be used forventilating full term neonate or infant.• When larger bags are used , only the force andtidal volume necessary to produce effective chestexpansion should be used.• Bag with fish mouth or leaf flap operated valveshould not be used to provide supplementaloxygen during spontaneous respiration.
Anesthesia Ventilation System• Consist of reservoir bag, an overflow port, fresh gas portand standard connector for mask or ET tube• For infant- 500ml; for children- 1000 to 2000ml; for adult-3000-5000ml is reqd.• More experience is reqd. to use• Fresh gas flow should be• <10 kg= 2l/min• 10-50 kg= 4L/min• >50 kg= 6L/min• Risk of barotrauma and hypercarbia is more• Effective ventilation is determined by adequate chestmovement.• PEEP or CPAP can be provided by adjusting pop off valve.
Endotracheal Airway• Most effective and reliable method of assistedventilation because:– The airway is isolated, ensuring adequateventilation and O2 delivery– Reduces aspiration chance– Interposition of ventilations with chestcompressions can be accomplished efficiently.– Insp. Time and PIP can be controlled– PEEP can be delivered.
Indications for Intubation• Inadequate CNS control of ventilation• Functional or anatomic airway obstruction• Loss of protective airway reflexes• Excessive work of breathing• Need of high PIP or PEEP• Need of MV support• Potential occurrence of any of the above ifpatient is transported
Endotracheal Tube• A cuffed ET tube is generally indicated forchildren aged 8-10 yrs or older.• In younger children normal anatomicnarrowing at the level of cricroid cartilageprovides a functional cuff.• ET tube size= age/4 + 4; length= age/2 +12 ordepth of insertion= tube size*3• ET tube 0.5 mm smaller and larger should bereadily available.
Oropharyngeal Airway• Flange + Bite block Segment+ curved body• Curved body is designed to fit over the back oftongue to hold it and soft hypophalengealstructures away from post. Pharyngeal wall.• Indicated in in unconscious pt. if procedure toopen airway fail to provide and maintain aclear, unobstructed airway.• Size: corner of mouth to angle of jaw
• Oropharyngeal airway should be inserted byusing the tongue depressor or• The airway can be inverted for insertion intothe mouth , using the curved portion asdepressor. As the airway approaches the backof oropharynx , it is rotated 180° into properposition.
Nasopharyengeal Airway• Soft rubber or plastic tube that provide airflow between naresand posterior pharyngeal wall• Shortened ET tube can also be used• Responsive pt. can tolerate well.• Length= tip of the nose to tragus of the ear• The airway is lubricated and inserted through the nostril in aposterior direction perpendicular to the plane of the face andpassed gently along the floor of nasopharynx.• Patency must be frequently evaluated• Too long size may irritate vagus nerve, epiglottis or vocalcords and stimulate cough, vomit or laryangospasm.
Summary• Low flow systems are:– Face mask-– Simple Face Mask– Partial rebreathing Mask– Venturi Mask– Face tent– Oxygen tent– Nasal Cannula
• High Flow Systems– Non Rebreathing Mask– Oxygen Hood– Bag Valve Mask Ventilation– Endotracheal Airway• Proper device should be selected according tothe patient’s need.• Proper size of device should be used foreffective oxygen delivery.
References• Pediatric Advance Life Support• Paramedic: Airway Management 2011• Pediatric Critical Care Medicine: Basic ScienceAnd Clinical Evidence edited by Derek S.Wheeler, Hector R. Wong, Thomas P. Shanley