2.Ventilator Settings by Dr.Ateia.pptx

Description of how to set up and modify mechanical ventilator settings

1. VENTELATOR SETTINGS DR- ATEIA EL MEHDOWI

2. : CONTENTS Manipulation of ventilators . Components of ventilator . Initial ventilator settings . Safety considerations in mechanical ventilators . Golden rules in mechanical ventilation .

3. Manipulation of ventilators The adjustment of ventilators requires recognition of: 1. Clinical and metabolic condition of the patient. 2. Characteristics of the machine. 3. A base line ABG is absolutely essential to determine the starting point for treatment of hypercapnia and acidosis and/or hypoxia. The PaCO2 level dose not have the same importance as pH level , since patient consciousness varies with acute versus chronic hypercapnia.

4. There should be a manual resuscitation bag at the bedside of every patient receiving mechanical ventilation. Ventilators are a method of life-support; if the ventilator stops working ??????

5. Physician Nurse RT Patient Ventilator Success of mechanical ventilation

6. COMPONENTS OF VENTILATORS Grouped into 4 categories: 1. Controls. 3. Alarms 2. Monitors. 4. External features & accessories.

7. CONTROLS

8. CONTROLS The number and type of controls in specific ventilator depend mostly on their purpose. Critical Care Neonatal Intensive Care Pediatric Intensive Care Unit Post Anesthesia Care Unit (PACU) Home MRI Transport – Ground/Air/Hospital OR

9.   A. Short-term ventilators: have fewer controls.   CONTROLS

10. They are more difficult to operate. A.  Long-term ventilators: They have large variety of controls They have great flexibility in clinical application   CONTROLS

11.   CONTROLS

12.   CONTROLS

13. 2- Microprocessor-controlled ventilators

14. Microprocessor-controlled ventilators

15.   Pressure . Volume (Vm & Vt ). Rate. FIO2. I/E ratio or I/E time. Insp . Flow. Sensitivity . Insp. Pause (inflation hold). PEEP.    Sigh (volume & frequency).   CONTROLS

16.  Tidal volume (Vt) The clinician sets:  Frequency  Trigger sensitivity.  PEEP VCV

17. (PCV) The clinician sets :  Peak inspiratory pressure (PIP) . ( Complete control of peak pressure) .  Frequency  Inspiratory time (It).  Rise time  Trigger sensitivity.  PEEP

18. e.g.. VCVs do not provide an independent pressure control. Control on ventilators may provide an approximate values. To confirm the accuracy of controls, an effective monitoring capability is needed. e.g.. PCVs do not provide an independent volume control .  T here are several functions for the ventilators have no controls, yet these must be monitored   CONTROLS ..

19. INITIAL VENTILATOR SETTINGS Mode of ventilation The initial mode of ventilation should be the assist control (A/C) mode . In the A/C mode, the work of breathing is reduced to only that amount of inspiration needed to trigger the machine's inspiratory cycle . A second possible advantage is that cycling the ventilator into the inspiratory phase maintains normal ventilatory activity and, therefore, prevents atrophy of the respiratory muscles.

20. The potential disadvantages of the A/C mode include respiratory alkalosis. A second possible disadvantage is that every breath is a full, preset, positive-pressure breath that influences venous return to the right heart and, possibly, to global cardiac output . Nevertheless , the A/C mode is the best initial mode of ventilation and may be switched to another option if hypotension occurs or hypocarbia is evident on the first arterial blood gas analysis.

21. Fractional Inspired Oxygen (FIO2) The fractional inspired oxygen is the amount of oxygen delivered to the patient. It can range from 21% (room air) to 100%. It’s recommended that the FIO2 be set at 1.0 (100%) upon the initiation of mechanical ventilation to allow the patient to get used to the ventilator without experiencing hypoxia.

22. A short period on FIO2 of 100% is not dangerous to the patient on mechanical ventilation and offers the clinician several advantages : protects the patient against hypoxemia if unrecognized problems develop from the intubation procedure. PaO2 measured on an FIO2 of 100%, the clinician can easily calculate the next desired FIO2 and quickly estimate the shunt fraction .

23. When the clinician wishes to change the PaO2, 2 variables might be adjusted FIO2 and the amount of PEEP . When using supplemental FIO2, improvement in oxygenation cannot reliably be achieved with changes in rate or tidal volume. With the target PaO2 identified, the FIO2 can be adjusted using the formula: New FIO2=(old FIO2 X desired PaO2)/measured PaO2.

24. The degree of shunt on 100% FIO2 can be estimated by a rough rule of thumb. The measured PaO2 is subtracted from 700 mm Hg. For each 100 mm Hg difference, a 5% shunt exists . A shunt of approximately 25% requires the use of PEEP.

25. Positive end-expiratory pressure [PEEP] PEEP therapy can be effective when used in patients with a diffuse lung disease that results in an acute decrease in functional residual capacity ( FRC) when used to treat patients with a diffuse lung disease, PEEP should improve compliance, decrease dead space, and decrease the intrapulmonary shunt effect. The most significant benefit of PEEP is that the patient can maintain an adequate PaO2 at a lower, safer concentration of oxygen (<60%), thereby reducing the risk of oxygen toxicity.

26. No recommendations exist for adding external PEEP during initial ventilator setup to satisfy misguided attempts to supply prophylactic PEEP or physiologic PEEP . Most clinicians use the lowest amount of positive pressure that provides an adequate PaO2 with a safe FIO2. PEEP

27. PEEP principally is used to lower the risks of oxygen toxicity and is employed when a safe PaO2 cannot be achieved at 60% FIO2. Initiated at 5 cm H2O , PEEP usually is increased in 3 cm H2O increments , while evaluating the effect on oxygenation every 15-20 minutes . A PEEP level of 10 cm H2O rarely causes hemodynamic problems in the absence of intravascular volume depletion.

28. changes in PEEP may not be reflected by changes in arterial blood gases for 20-30 minutes so changes in the PEEP setting should usually not be made faster than this PEEP over 20 cm is rarely beneficial and usually results in additional pressure-induced lung injury

29. BEST PEEP ? The exact amount of PEEP applied is very controversial ?????????????????????????????????

30. Pressure (cm H 2 O) 50 Volume (ml) 1500 Alveoli elastic limit UIP LIP Alveoli open Alveolar collapse PEEP Pressure limit Pressure-volume curve

31. The titration of PEEP above the lower inflection point  increases lung compliance “ best PEEP ”. The titration of PIP below the upper inflection point  prevention of over destintion Pressure-Volume loope

32. 400 600 200 0 5 10 20 30 40 50 Press Vt 300 500 700 100 Lower inflection point Upper inflection point PIP PEEP Safe ventilation Pressure-Volume loope

33. The respiratory rate is the number of breaths that the ventilator delivers to the patient each minute . The rate chosen depends on the : Tidal volume. Type of pulmonary pathology . patient’s target PaCO2. Respiratory Rate (RR)

34. Patients with restrictive lung disease usually tolerate a range of 12-20 breaths/minute. Patients with normal pulmonary mechanics can tolerate a rate of 8-12 breaths/minute. For patients with obstructive lung disease, the rate should be set at 6-8 breaths/minute to avoid the development of auto-PEEP and hyperventilation, or “blowing off CO2.”. Patients with obstructive lung disease often adapt to a higher PaCO2, so lowering it back to the “normal” range of 35-45 mm Hg may not be beneficial.

35. The respiratory rate parameters are set above and below this number and the alarm will then sound if the patient’s actual rate is outside of the desired range.

36. The usual setting is 5-12 cc/kg . based on compliance, resistance, and type of pathology. Tidal Volume (VT) Patients with normal lungs can tolerate a tidal volume of 10-12 cc/kg , Patients with restrictive lung disease may need a tidal volume of 5-8 cc/kg .

37. Tidal Volume (VT) Males Ideal body weigh IBW = 50+2.3 (Height (inches) – 60 ) Females Ideal body weigh IBW = 50+2.3 (Height (inches) – 60 )

38. The tidal volume alarm level are set above and below the desired number, and the alarm will sound if the patient’s actual tidal volume is outside of the desired range. Tidal Volume (VT)

39. Double-checking the selected tidal volume After a tidal volume is selected, the peak airway and Plateau pressures pressure should be determined peak airway pressure <45 cm H2O. plateau pressure is < 30-35 cm H2O .

40. Tow Pressure level :  Small values , which just to compensate for resistance of the ETT.  Large values , that make the spontaneous breath equivalent to triggered mandatory breath (PCV). Pressure suppot PS

41. Pressure support PS only eliminates the work precisely at a given flow. Above and below that flow, PS under compensates for resistance or over compensates.

42. (Weaning) ATC ATC compensation can overcome resistance regardless of patient flow demand.

43. The I:E ratio is usually set at 1:2 or 1:1.5 to approximate the normal physiology of inspiration and expiration. Occasionally, a longer inspiratory than expiratory time is desired to allow more time to oxygenate the patient’s lungs. This is called inverse ratio ventilation. Inspiratory:Expiratory (I:E) Ratio

44. The pressure limit regulates the amount of pressure the VCV can generate to deliver the preset tidal volume. Because high pressures can cause lung injury, it’s recommended that the plateau pressure not exceed 35 cm H20. If this limit is reached, the ventilator stops delivering the breath and alarms. This may be an indication that the patient’s airway is obstructed with mucus . It can also be caused by the patient coughing, biting on the ETT , breathing against the ventilator , or by a kink in the ventilator tubing . Pressure Limit

45. The flow rate is the speed with which the tidal volume is delivered. Flow Rate The usual setting is 40-100 liters per minute.

46. The sensitivity determines the amount of effort required by the patient to initiate inspiration. Sensitivity/Trigger It can be: Pressure triggering 1 – 2 cm H2O flow triggering. 1- 5 L/min Flow triggering is a better setting for patients who can breathe spontaneously because it reduces the work of breathing. time pressure trigger- threshold

47. Very fast rising Depending on rise time, the beginning of the flow will be or slower Rise time For adults the range is 0-0.4 seconds

48. The ventilator can be programmed to deliver an occasional sigh with a larger tidal volume. The use of frequent sighs was popular during the 1970’s because it was thought that it prevented collapse of the alveoli (atelectasis), which can result from the patient constantly inspiring the same volume of gas. However, recently there has been concern that the increased pressure produced in the alveoli may heighten the risk of the alveoli rupturing and causing pneumothorax. Sigh

49. Summary of initial ventilator set up A/C Mode Tidal volume depending on lung status Normal lungs - 12 cc/kg ideal body weight COPD - 10 cc/kg ideal body weight ARDS - 6-8 cc/kg ideal body weight Rate of 10-12 breaths per minute FIO2 of 100% Sighs rarely needed PEEP only as indicated after first arterial blood gas Shunt greater than 25% Inability to oxygenate with safe FIO2

50. What is ASV? Conventional T p Rate P sup P insp T i T e @ FiO 2 PEEP V t CMV SIMV PCV PSV Goal 3: Simple to use Modes Controls

51. What is ASV? Conventional T p Rate P sup P insp T i T e @ FiO 2 PEEP V t CMV SIMV PCV PSV ASV Goal 3: Simple to use Controls

52. What is ASV? Conventional T p Rate P sup P insp T i T e @ FiO 2 PEEP V t CMV SIMV PCV PSV ASV Goal 3: Simple to use

53. What is ASV? Conventional T p Rate P sup P insp T i T e @ FiO 2 PEEP V t CMV SIMV PCV PSV ASV Goal 3: Simple to use

54. T p Rate P insp T i T e PF FiO 2 PEEP V t CMV SIMV PCV PSV Alveolar Ventilation Oxy. Conventional FiO 2 PEEP MV Automatic Mechanical ventilation

55. 2. MONITORS Ventilators are designed to monitor many components of the patient’s respiratory status.

56. Patient monitoring

57. peak , mean , plateau and PEEP. Pressure:

58. Vt, Vm, sigh volume. Volume:   Frequency (mandatory & spontaneous). MONITORS

59.    I/E ratio It, Et.    FIO2. MONITORS

60. Lung mechanics Monitoring Flow-time curve Pressure-time curve Volume-pressure loop Flow-volume loop Nigative inspiratory force (NIF) AutoPEEP Airway Resistance Lung compliance

61. 3. Alarms Help Something is wrong

62. 3. ALARMS To ensure the safety and effectiveness of MV electric or pneumatic alarms are installed on ventilator to signal both visually and audibly the presence of undesirable conditions.

63. Problem solving pCO2 too high !!!!!!!!!!!!!! pO2 too low !!!!!!!!!!!!!!!!!!!!!!!!!! PIP too high !!!!!!!!!!!!!!!!!!!!!!! ????????????????????????????????

64. Safety considerations in mechanical ventilators Back up ventilation Low resistance non compliant breathing circuit Limits on closed loop adjustments Reliable alarm system Battery for electrical failure

65. Golden rules in mechanical ventilation 10

66. 5- Adapt the ventilator to the patient instead of adapting the patient to the ventilator. 2- A mode doesn’t make the lung healthy it wins only time . 3- Keep healthy parts of the lung healthy. 4- Maintain and support spontaneous breathing in ventilated patient . 1- Start the process of weaning the moment you start mechanical ventilation.

67. 8- Avoid airway pressure more than 35 cmH2O 6- Employ tidal volume of 6 – 8 ml/kg Wt. 9- Don’t be too shy with PEEP . 10- Set always the trigger at the highest sensitivity (avoid autocycling ).             7- Give 7 – 8 cmH2O pressure support for compensation of the tube resistance. Vt PS PAP PEEP Triggering

68. pCO 2 Too High Patient ’ s minute ventilation is too low. Increase rate or TV or both. If using PC ventilation, increase PIP. If PIP too high, increase the rate instead. If air-trapping is occurring, decrease the rate and the I-time and increase the TV to allow complete exhalation.

69. pO 2 Too Low Increase either the FiO 2 or the mean airway pressure (MAP). Try to avoid FiO 2 >70%. Increasing the PEEP is the most efficient way of increasing the MAP in the PICU. Can also increase the I-time to increase the MAP (PC). Can increase the PIP in Pressure Control to increase the MAP, but this generally doesn ’ t add much at rates <30bpm.

70. PIP Too High Decrease the PIP (PC) or the TV (VC). Increase the I-time (VC). Change to another mode of ventilation. Generally, pressure control achieves the same TV at a lower PIP than volume control. If the high PIP is due to high airway resistance, generally the lung is protected from barotrauma unless air-trapping occurs.

71. Acute Deterioration DIFFERENTIAL DIAGNOSES Pneumothorax Right main stem intubation Pneumonia Pulmonary edema Airway occlusion Ventilator malfunction Mucus plugging Air leak hypoperfusion

72. 6. Expiratory Hold Auto PEEP

73. Failure of expiratory flow to return to the baseline before next inspiration Normal flow Auto-peep Flow L/min Time Trapped volume Auto PEEP

74. Auto PEEP Expiratory Hold