Modalities of oxygen therapy in picu 31 3-14


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Modalities of oxygen therapy in picu 31 3-14

  1. 1. Modalities of oxygen therapy in PICU Dr Suresh Kumar. MBBS, MD, FIAP (PCC), DNB, PGDS, DM (fellow, PCC) 31-3-14
  2. 2. Overview  Need of oxygen therapy  Oxygen delivery system  Oxygen delivery devices  Individual oxygen delivery devices and techniques  Humidification  Complication of oxygen therapy  Practical considerations
  3. 3.  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
  4. 4.  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
  5. 5. 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
  6. 6.  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 = 100 PAO2 = 0.50 X 713 - 40/0.8 = 306 PAO2 = 0.80 X 713 - 40/0.8 = 520
  7. 7. 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
  8. 8. 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
  9. 9. Oxygen delivery system  Oxygen source  Pressure regulator and flow meter  Oxygen delivery device  Patient
  10. 10. Patient Indications 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
  11. 11. 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
  12. 12. 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
  13. 13. 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
  14. 14. Oxygen delivery devices…  Classified as: Low-flow or variable-performance devices: Provide oxygen at flow rates that are lower than patients’ inspiratory demands When the total ventilation exceeds the capacity of the oxygen reservoir, room air is entrained FiO2 delivered depends on the ventilatory demands of the patient, the size of the oxygen reservoir, and the rate at which the reservoir is filled At a constant flow, the larger the tidal volume, the lower the FiO2 and vice versa FiO2 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 air Reliable
  15. 15. Oxygen delivery devices…  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
  16. 16. Oxygen delivery devices…  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
  17. 17. Oxygen delivery devices…  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 Heliox Hyperbaric oxygen
  18. 18. Oxygen delivery devices… 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
  19. 19.  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
  20. 20. 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
  21. 21. 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%
  22. 22. Nasal cannula/prongs…  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
  23. 23. Nasal cannula/prongs…  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
  24. 24. 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
  25. 25. 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
  26. 26. 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
  27. 27. 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
  28. 28. 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
  29. 29. 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%
  30. 30. Partial rebreathing face masks…  Indications:  Relatively high FiO2 requirement  Contraindications:  Poor respiratory efforts, apnea, severe hypoxia  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%
  31. 31. 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%
  32. 32. Non-rebreathing face masks…  Indications:  High FiO2 requirement >40%  Contraindications:  Poor respiratory efforts, apnea, severe hypoxia  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
  33. 33. 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
  34. 34. 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
  35. 35. 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
  36. 36. 3: 24% 3: 26% 6: 28% 6: 30% 9: 35% 12: 40% 15: 50%
  37. 37. Venturi masks or Air-entrainment masks…  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
  38. 38. Venturi masks or Air-entrainment masks…  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
  39. 39. 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
  40. 40. 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
  41. 41. Oxygen tent  Clear plastic sheet that cover child’s upper body  FiO2 50%  Not reliable  Limit access to patient  Not useful in emergency situations
  42. 42. ,
  43. 43. 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
  44. 44. 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
  45. 45. 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)
  46. 46. 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
  47. 47. 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
  48. 48. High flow nasal prongs… 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
  49. 49. High flow nasal prongs… 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
  50. 50. High flow nasal prongs… 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
  51. 51. High flow nasal prongs…  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 2009 High-flow nasal cannula oxygen therapy for infants with bronchiolitis: Pilot study. J Paediatr Child Health. 2014 High-flow nasal cannula (HFNC) support in interhospital transport of critically ill children Intensive care med 2014 High-flow nasal prong oxygen therapy or nasopharyngeal continuous positive airway pressure for children with moderate-to-severe respiratory distress? Pediatr Crit Care, 2013 High-flow nasal cannula therapy for respiratory support in children. Cochrane Database Syst Rev.2014 Mar 7;3:CD009850 Reduced intubation rates for infants after introduction of high-flow nasal prong oxygen delivery. Intensive Care Medicine. 2011
  52. 52. 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
  53. 53. 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
  54. 54. 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
  55. 55. 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)
  56. 56. 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
  57. 57. 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 problematic Density, viscosity, and thermal conductivity of helium affect the delivered tidal volume and the measurement of exhaled tidal volume
  58. 58. 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
  59. 59. 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
  60. 60. 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
  61. 61. 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)
  62. 62. 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
  63. 63. 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
  64. 64. 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)
  65. 65. 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
  66. 66. 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
  67. 67. 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
  68. 68. 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
  69. 69. 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
  70. 70. 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%
  71. 71. 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
  72. 72. 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
  73. 73. 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
  74. 74. References   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
  75. 75. THANK YOU