-Seminar-Oxygen Delivery Devices.pptx2016

Nice pot on various oxygen delivery device

1. Oxygen delivery devices Dr Reshma Aramanadka 18.3.2017

2. Objectives Oxygen therapy Types of oxygen delivery devices Low flow devices High flow devices High flow nasal cannula

3. Discovery of oxygen Laboratory discovery of oxygen-1771 Carl Wilhelm Scheele- German-Swedish pharmaceutical chemist “Fire air”- heating mercuric oxide, silver carbonate, magnesium nitrate, and other nitrate salts. Isaac Asimov, American writer of science & science fiction books, called him “ hard luck Scheele” First to discover oxygen and a number of other elements, including molybdenum, tungsten, barium, hydrogen, and chlorine, but credit went to others The Story of Oxygen. Heffner J E Respiratory Care January 2013

4. Application in medicine 1798: Thomas Beddoes- father of respiratory therapy Collaborated with the inventor James Watt- Pneumatic Institute in Bristol, England Oxygen and nitrous oxide to treat asthma, congestive heart failure, and other ailments 18th and early 19th centuries, apothecaries in England- through generation by electrolysis 186 8: first cylinders for storing O2 1917: Haldane- ‘The therapeutic administration of oxygen’ Origin of rational oxygen use Regulation of respiratory drive by carbon dioxide and its effects on blood H+ concentration

5. Disordered control Upper airway obstruction Lower airway obstruction Alveolocapillary membrane Abnormal Hb Shock

6. Common indications for oxygen therapy Respiratory distress/ failure- respiratory/ cardiac pathology Dyspnea, tachypnea, bradypnea, apnea Pallor, cyanosis Lethargy or restlessness Use of accessory muscles: nasal flaring, intercostal or sternal recession, tracheal tug Circulatory compromise/ shock Pulmonary hypertension Short term therapy: post anesthetic or surgical procedure Palliative care: for comfort

7. How it works? Increasing the inspired O2 fraction (FiO 2 ) Increases the alveolar PO 2 (PAO 2 ) and subsequently the arterial PO 2 (PaO 2 ) PAO 2 = FiO 2 (PB - 47) – (PaCO2/RQ) 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 PAO 2 = 0.21 X 713 - 40/0.8 = 100 PAO 2 = 0.50 X 713 - 40/0.8 = 306 PAO 2 = 0.80 X 713 - 40/0.8 = 520

8. Goals of oxygen therapy Maintain targeted SpO 2  levels through supplementing oxygen in a safe and effective way Relieve hypoxemia/ maintain adequate tissue oxygenation Reduce work of breathing Efficient and economical use of oxygen (costly) Ensure adequate clearance of secretions Limit the adverse events of hypothermia, insensible water loss, avoid CO2 retention, etc.

9. Oxygen delivery system Oxygen source Pressure regulator and flow meter Oxygen delivery device Patient

10. Oxygen sources Medical oxygen can be provided from a Wall source (central oxygen supply) Provide 60 psi (pounds per square inch ) of pressure Cylinder Operate at 1800-2400 psi Too much pressure – highly compressed Cannot be directly delivered to patient Regulating valve and flow meter to manipulate the flow rate

11. 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 patient The flow-rate can be set from 1-15 L/min

12. Oxygen delivery devices Devices used to administer, regulate, and supplement oxygen to a subject to increase the arterial oxygenation Entrains oxygen and/or air to prepare a fixed concentration required for administration

13. Respiratory gas flow requirement 3-4 time the minute ventilation 3 x 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 = 5.4-7.2 L/min = Approx. 6 L/min

14. Air entrainment- concept Low flow devices High flow devices

15. Low-flow or variable-performance devices Provide oxygen at flow rates that are lower than patients’ inspiratory demands At a constant flow, the larger the tidal volume, the lower the FiO 2  and vice versa Variable FiO2 FiO2 24-100%

16. Nasal cannula Intranasal catheter Simple mask Partial rebreathing masks Non rebreathing mask Low-flow or variable-performance devices

17. Basic concepts-low flow devices A low-flow system requires that patient inspire some room air to meet inspiratory demands FiO 2  is determined by size of oxygen reservoir, oxygen flow rate, MV Oxygen reservoir volume has to be increased (placing a mask over the nose and mouth) to achieve an FiO 2  greater than 40% The larger the tidal volume, or the faster the respiratory rate, the lower the FiO 2

18. High-flow or fixed-performance devices Deliver gas at flow rates that exceed the patient’s inspiratory flow rate and by entraining a fixed proportion of room air Reliable

19. Venturi system Oxyhood Face tent Oxygen tent High flow nasal cannula oxygen High-flow or fixed-performance devices

20. Oxygen delivery devices… Common confusion : Type of flow system & oxygen concentration delivery A high-flow system, viz. Venturi mask, can deliver FiO 2  as low as 0.24, whereas a low-flow system like a non rebreathing mask can deliver FiO 2  as high as 1.0 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

21. Type of device to be used Age Underlying diagnosis Level of consciousness Setting where the therapy is administered Presence or absence of artificial airway Expertise of the unit with the device Fit of the device Patient acceptance and tolerance

22. Nasal cannula/prongs Two soft prongs in nostrils attached to the oxygen source Flow is directed to the nasopharynx: humidification and heat exchange occurs there To ensure the patient is able to entrain room air around the nasal prongs Prong size should be approximately half the diameter of the nares – not complete seal Available in different sizes

23. Nasal cannula/prongs… Delivers 24-44% FiO2 at flow rate of  1-6 L/min The slower the inspiratory flow, the higher the FiO 2   A maximum flow of: 2 LPM in infants/children under 2 years of age 4 LPM for children over 2 years of age If flow required > 2 L/min, it can be uncomfortable Consider alternate device if high flow required If flow >6 L/min, variable FiO2, need humidification 1 = 24% 2 = 28% 3 = 32% 4 = 36% 5 = 40% 6 = 44%

24. Nasal cannula Indications Low to moderate FiO2 requirement No or mild respiratory distress Home oxygen therapy Contraindications Poor efforts, apnea Severe hypoxia Mouth breathing Advantages Less expensive Comfortable, well tolerated Able to talk and eat Disadvantages Does not deliver high FiO2 Irritation and nasal obstruction Less FiO2 in nasal obstruction FiO2 varies with breathing efforts

25. 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 are away from the patient's neck to prevent risk of airway obstruction Checking the nares for patency of the prongs, drying, bleeding Practical Considerations

26. Intranasal catheters Flexible catheter with multiple holes at distal 2 cms FiO2 35-40% delivered usually 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

27. 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

28. Simple masks Indications : Short-term use Operative procedures For those patients where a nasal cannula is not appropriate Advantages : Less expensive Can be used in mouth breathers No nasal irritation Does not require use of adhesives Contraindications : Poor respiratory efforts, apnea, severe hypoxia Disadvantages Uncomfortable Requires tight seal- skin erosion Does not deliver high FiO2 FiO2 varies with breathing efforts Interfere with feeding, speaking

29. Practical considerations Pediatric and adult sizes (100 ml & 300 ml) Select a mask which best fits from the child's bridge of nose to the cleft of jaw 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

30. Partial rebreathing face masks Simple masks with additional reservoir Allows for the initial portion of the expired gases containing little or no CO 2  (rich in oxygen) to be collected in a reservoir while the remaining expiratory gases are vented to the atmosphere

31. Practical considerations with PRM Fi O 2  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: 50% 10: 60% 12: 60% 15: 60%

32. Partial rebreathing face masks… Indications: Relatively high FiO 2 requirement Advantages: Inspired gas not mixed with room air Patient can breath room air through exhalation ports if supply get interrupted Disadvantages: More oxygen flow does not increase FiO 2 Interferes with eating and drinking 6: 35% 8: 50% 10: 60% 12: 60% 15: 60%

33. 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 ) Prevents the room air from being entrained @ 10-15 L/min  FiO2 90-100% 6: 55-60% 8: 60-80% 10: 80-90% 12: 90-95% 15: 90-100%

34. Non-rebreathing face masks… Indications: High FiO2 requirement >40% Acute cardiopulmonary emergencies Contraindications: Poor respiratory efforts, apnea, severe hypoxia Advantage: Highest possible FiO2 without intubation Suitable for spontaneously breathing patients with severe hypoxia Disadvantage Relatively expensive Requires tight seal, Uncomfortable Interferes with eating and drinking Not suitable for long term use Malfunction can cause CO 2 buildup, suffocation

35. Practical considerations NRM Ensure flow rate to the mask is adequate to maintain fully inflated reservoir bag during entire respiratory cycle Do not use with humidification system as this can cause excessive 'rain out‘ Flow rate must be sufficient to keep bag 1/3  to  1/2  inflated  at all times Avoid kinking and twisting of reservoir

36. Venturi masks or air-entrainment masks Venturi mask mixes oxygen with room air, creating high-flow enriched oxygen of a settable concentration It provides an accurate and constant FiO 2 in range of 24-50% Venturi mask is often employed when clinician has a concern about CO 2  retention 

37. Venturi masks Dilutional masks Work on Bernoulli principle Oxygen is delivered through jet nozzle, which increases its velocity High-velocity O2 entrains ambient air into mask due to viscous shearing forces between gas traveling through the nozzle and 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% FiO 2 at 4-15 L/min

38. 3: 24% 3: 26% 6: 28% 6: 30% 9: 35% 12: 40% 15: 50%

39. Venturi masks Indications: Desire to deliver exact amount of FiO2 Any of the previous indications Advantages: Fine control of FiO2 at fixed flow Fixed, reliable, and precise FiO2 Does not dry mucus membranes High flow comes from the air, saving the oxygen cost Contraindications Poor respiratory efforts, apnea, severe hypoxia Disadvantages Uncomfortable Relatively expensive Cannot deliver high FiO2 Interfere with eating and drinking

40. Practical considerations ( Venturi ) Oxygen must be humidified and warmed Not effective for delivering FiO 2  greater than 50% Desired FiO 2 determines oxygen flow and total flow rates of gas To ensure that the patient's ventilatory requirements are met the total flow must exceed the patient's minute ventilation

41. Oxyhood FiO2: 80-90% @ Flow 10-15 L/min 3-4 sizes are available Too big  dilute the oxygen; Too small  discomfort and CO 2 retention Adequate flow of humidified oxygen-> mixing of delivered gases and flushing out CO 2 Oxygen gradient can vary as 20% from top to bottom (Layering) Ensure a gap all around child’s neck- important to prevent re-breathing of CO2

42. Face tent/face shield High flow soft plastic bucket Well tolerated by children viz. face mask @ 10-15 L/min  40% FiO2 Access for suctioning without need for interrupting oxygen

43. Oxygen tent Clear plastic sheet that cover child’s upper body FiO2-variable Limit access to patient Has to be kept closed at all times Cumbersome Not useful in emergency situations

44. Low flow v/s high flow oxygen delivery device in ALRI Methods: A total of 65 children, aged 3-36 months, diagnosed with ALRI, were enrolled. Received oxygen through an oxygen mask or through a Venturi mask. Results: After 24 h of treatment, respiratory rate was significantly lower among patients in the Venturi mask group Duration of supplemental oxygen and length of hospitalization were significantly lower in the Venturi mask group Uygur et al. Pediatr Int. 2016 Jan

45. HIGH FLOW NASAL CANNULA

46. High flow nasal cannula Provides oxygen and continuous positive airway pressure Gas heated to about 34 deg C Humidified with a relative humidity of >95% Delivers a precise FiO2 Improves FRC and reduces work of breathing Humidification avoids drying of respiratory secretions and for maintaining nasal cilia function

47. Other mechanisms of HFNC 1. Washout of nasopharyngeal dead-space & improved alveolar ventilation 2. Reduction in the inspiratory resistance associated with the nasopharynx 3. Improvement in conductance and pulmonary compliance 4. Reduction in metabolic work associated with gas conditioning 5. May provide positive distending pressure for lung recruitment Dysart K, et al. Respir Med 2009

48. High flow nasal cannula Indications Bronchiolitis, pneumonia, Congestive heart failure Respiratory support post-extubation Post surgical patients Children with neuromuscular disease Procedural sedation Contraindications Blocked nasal passages/choanal atresia Trauma/surgery to nasopharynyx Complications Gastric distension Pneumothorax

49. Uses in neonates Alternative to nCPAP support in any baby with mild/ moderate respiratory distress Infants with chronic lung disease Post- extubation non-invasive respiratory support Relief in babies who have already sustained nasal/skin trauma from nCPAP Treatment or prevention of apnoea of prematurity

50. PEEP delivered with HFNc Authors(year) Study subjects PEEP delivered Sreenan et al (2001) Preterm newborns CPAP of 6 cm H 2 O, as measured by equivalent esophageal pressures (4.5-4.6 cm H 2 O) Lampland et al (2009) Newborns <4cm H2O Spentzas et al (2009) Children 4.0 +/- 1.99 cm H(2)O. Groves et al (2007) Adults With mouth open – 2 to 3 cm H2O(pharynx) With mouth closed- 5 to 7 cm H2O

51. Does it produce clinically measurable results in children? Data were collected at time 0 (before the use of high-flow), time 2 (60 to 90 min post-application), and at time 3 (8 to 12 hours post-application). Significant improvements in the modified COMFORT score, respiratory clinical scale and oxygen saturation. X-rays taken after initiation of HFNC showed either improved aeration of the lungs or no changes in 40 of 46 patients. Spentzas T, et al. J Intensive Care Med 2009 Sep-Oct

52. Observations in children 72 children received HFNC and 37 received nasopharyngeal continuous positive airway pressure Children with pneumonia, bronchiolitis, pre and post op cardiac surgery patients, neuromuscular disorders Need for escalation- failure of normalization of heart rate and respiratory rate, and if the Fio2 did not fall to lower than 0.5, 2 hours after starting high-flow nasal prong therapy Nasopharyngeal continuous positive airway pressure was required for significantly longer periods than high-flow nasal prong Brink et al. PCCM2013

53. Practical considerations- HFNC

54. Initiation of HFNC Secure nasal cannula on patient using supplied "wiggle pads™“ Start the high flow nasal cannula system at the following settings: Flow rate ≤10Kg  2 L per kg per minute >10Kg  2 L per kg per minute for the first 10kg + 0.5L/kg/min for each kg above that (max flow 50 L/min) For example, 16kg= 20L (2 x first 10kg) + 3L (0.5 x 6kg) = 23L/min Flow should be rounded down to nearest available flow Royal children’s hospital, Melbourne protocol. Duke T, et al. 2013

55. Prong size

56. Monitoring of a child on oxygen therapy Monitor patient for response Respiratory rate, heart rate, degree of chest in­drawing, SpO2 Chest indrawing and other signs of respiratory distress should improve Seek medical review if any of the following occurs: The patient is not stabilising as described above The degree of respiratory distress worsens Persisting hypoxemia Observe for worsening sensorium

57. Weaning When the child's clinical condition is improving as indicated by: Decreased work of breathing Normal or improved respiratory rate Return to normal cardiovascular parameters Wean FiO2 to 21% Patient who is stable <30% oxygen,  flow can be weaned to 1 to 2 L/min via simple nasal prongs, or oxygen therapy ceased.  No need for prolonged weaning

58. To summarise , Oxygen is a drug- use judiciously Rational prescription- order FiO2, rate and method required Availability, cost, comfort and ease of application of each device Appropriate device for appropriate patient Clinical monitoring for effects and adverse effects essential

59. Thank you for your attention!