Downloaded 793 times
![Desired FiO2
If Age< 60, PO2 =104-age x 0.43
If Age >60, PO2 =80-(age-60)
Pao2 = (713 x Fio2)- Pco2/0.8
A2a2= PAo2/Pao2
Desired Fio2=
[(pO2/A2a2+pCO2/0.8)/713]x100%
dr.shumaylaaslam@gmail.co
m
14](https://image.slidesharecdn.com/basicmechventsettings-190408022804/75/Basic-mechanical-ventilation-settings-13-2048.jpg)
Uploaded byDr Shumayla Aslam-Faiz
Basic mechanical ventilation settings
The document discusses the basics of mechanical ventilation, including its indications, types, and key parameters essential for effective patient care. It outlines different modes of ventilation such as volume-controlled, pressure-controlled, and pressure support ventilation, along with their specific settings and complications. Additionally, it emphasizes the goals of mechanical ventilation while addressing patient comfort and the importance of informed decision-making regarding life support interventions.
More Related Content
Similar to Basic mechanical ventilation settings
![Mechanical_ventilation[_fellow[1][1][1][1].ppt](https://cdn.slidesharecdn.com/ss_thumbnails/mechanicalventilationfellow1111-240923152440-d96712e3-thumbnail.jpg?width=640&height=640&fit=bounds)
More from Dr Shumayla Aslam-Faiz
Basic mechanical ventilation settings
- 1. Basic Modes of Mechanical Ventilation ShumaylaAslam-Faiz, MD 3rd year IM resident [email protected] 1
- 2. • Mechanical ventilationis a useful modality for patients who are unable to sustain the level of ventilation necessary to maintain the gas exchange functions (oxygenation and carbon dioxide elimination). • Ventilator: A machine that generates a controlled flow of gas into a patient’s airways Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 2
- 3. Indication Clinical Application ofMechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 3
- 4. https://www.uptodate.com/contents/image?imageKey=PULM%2F67457&topicKey=PULM%2F1640&search=mechanic al%20ventilation&source=outline_link&selectedTitle=1~150 Alveolar filling processes Pneumonitis- infectious, aspiration Noncardiogenic pulmonary edema/ARDS (eg, due to infection, inhalation injury, near drowning, transfusion, contusion, high altitude) Cardiogenic pulmonary edema Pulmonary hemorrhage Tumor (eg, choriocarcinoma) Alveolar proteinosis Intravascular volume overload of any cause Hypoventilation: chest wall and pleural disease Kyphoscoliosis Trauma (eg, flail chest) Massive pleural effusion Pneumothorax Increased ventilatory demand Severe sepsis Septic shock Severe metabolic acidosis Indications [email protected] m 4
- 5. https://www.uptodate.com/contents/image?imageKey=PULM%2F67457&topicKey=PULM%2F1640&search=mechanic al%20ventilation&source=outline_link&selectedTitle=1~150 Pulmonary vascular disease Pulmonarythromboembolism Amniotic fluid embolism, tumor emboli Diseases causing airways obstruction: central Tumor Laryngeal angioedema Tracheal stenosis Diseases causing airways obstruction: distal Acute exacerbation of chronic obstructive pulmonary disease Acute, severe asthma Hypoventilation: decreased central drive General anesthesia Drug overdose Hypoventilation: peripheral nervous system/respiratory muscle dysfunction Amyotrophic lateral sclerosis Cervical quadriplegia Guillain-Barré syndrome Myasthenia gravis Tetanus, tick bite, ciguatera poisoning Toxins (eg, strychnine) Muscular dystrophy, myotonic dystrophy, myositis Indications [email protected] m 5
- 6. Goals of MechanicalVentilation Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 6
- 7. There are threeconsiderations in which mechanical ventilation should be terminated or should not be started They are based on (1) patient’s informed request, (2) medical futility (A condition in which medical interventions are useless based on past experience), (3) reduction or termination of patient pain and suffering. Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 7
- 8. Types of Ventilation •Negative pressure ventilation • Positive pressure ventilation – Simple pneumatic system – New generation microprocessor controlled systems. Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 9
- 9. Basic Ventilator Parameters •Mode • Tidal volume • Frequency or back up rate • FiO2 • PEEP • Flow rate • I:E Ratio • Triggers Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 10
- 10. Tidal Volume • initialtidal volume is usually set between 6 and 8 mL/kg of predicted body weight. • Tidal volumes </= 6 mL per kg of predicted body weight have been recommended for ARDS patients Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 11
- 11. Frequency (Back UpRate) • the number of breaths per minute that is intended to provide eucapneic ventilation (PaCO2 at patient’s normal) • The initial frequency is usually set between 12 and 16/min. • Frequencies of 20/min or higher are associated with auto-PEEP and should be avoided. – high ventilator frequency, inadequate inspiratory flow and air trapping contribute to the development of auto- PEEP. https://www.uptodate.com/contents/modes-of-mechanicalventilation [email protected] m 12
- 12. FIO2 • Fraction ofinspired Oxygen – The initial FIO2 may be set at 100%. – should be evaluated by means of ABG after stabilization of the patient. • should be adjusted accordingly to maintain a PaO2 between 80 and 100 mm Hg. • After stabilization of the patient, the FIO2 is best kept below 50% to avoid oxygen induced lung injuries • Can be assed by SpO2, maintaing >/= 96% Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 13
- 13. Desired FiO2 If Age<60, PO2 =104-age x 0.43 If Age >60, PO2 =80-(age-60) Pao2 = (713 x Fio2)- Pco2/0.8 A2a2= PAo2/Pao2 Desired Fio2= [(pO2/A2a2+pCO2/0.8)/713]x100% [email protected] m 14
- 14. PEEP • Positive end-expiratorypressure (PEEP) – PEEP reinflates collapsed alveoli and supports and maintains alveolar inflation during exhalation. • increases the functional residual capacity • useful to treat refractory hypoxemia. – The initial PEEP level may be set at 5 cm H2O – Auto-PEEP is present when the end-expiratory pressure does not return to baseline pressure at the end of expiration. Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 15
- 15. Clinical Application ofMechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 16
- 16. • Complications ofPEEP (1)decreased venous return and cardiac output, (2)barotrauma, (3)increased intracranial pressure, and (4)alterations of renal functions and water metabolism. https://www.uptodate.com/contents/modes-of-mechanicalventilation [email protected] m 18
- 17. Flow rate • Thepeak flow rate is the maximum flow delivered by the ventilator during inspiration. • The inspiratory flow needs to be sufficient to overcome pulmonary and ventilator impedance otherwise the work of breathing is increased. • Peak flow rates of 60 L per minute may be sufficient, • higher rates are frequently necessary in patients with bronchoconstriction. https://www.uptodate.com/contents/modes-of-mechanicalventilation [email protected] m 19
- 18. • An insufficientpeak flow rate is characterized by – dyspnea, – spuriously low peak inspiratory pressures, – scalloping of the inspiratory pressure tracing [email protected] m 20
- 19. I:E Ratio • TheI:E ratio is the ratio of inspiratory time to expiratory time. • It is usually kept in the range between 1:2 and 1:4 • A larger I:E ratio – possibility of air trapping – auto-PEEP • Inverse I:E ratio – correct refractory hypoxemia in ARDS patients Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 21
- 20. • I:E ratiomay be altered by manipulating any one or a combination of the following controls: (1) flow rate, (2) inspiratory time, (3) inspiratory time %, (4) frequency, and (5) minute volume (tidal volume and frequency). Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 22
- 21. Clinical Application ofMechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 23
- 22. Trigger There are twoways to initiate a ventilator-delivered breath: 1. pressure triggering – initiated if the demand valve senses a negative airway pressure deflection (generated by the patient trying to initiate a breath) greater than the trigger sensitivity. – A trigger sensitivity of -1 to -3 cm H2O is typically set 2. flow-by triggering – initiated when the return flow is less than the delivered flow, a consequence of the patient's effort to initiate a breath – the trigger sensitivity is usually set at 2 L/min https://www.uptodate.com/contents/modes-of-mechanicalventilation [email protected] m 24
- 23. Mode • Volume-Controlled Ventilation –set volume delivered with each breath – volume delivery fixed, pressure will vary, depending upon pulmonary compliance and airway resistance. – The advantage of volume control is the ability to regulate both tidal volume and minute ventilation (tidal volume x BUR) Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 25
- 24. • Pressure-Controlled Ventilation –peak inspiratory pressure for each mechanical breath. – pressure remains constant, volume and minute ventilation will vary with changes in the patient’s pulmonary compliance or airway resistance – The advantage of the pressure-controlled mode is that the lungs can be protected from excessive pressures, preventing ventilator- induced lung injury (VILI) Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 26
- 25. • Dual controlmode – is a combined mode between two control variables – When VCV and PCV are combined, the patient receives mandatory breaths that are volume-targeted, pressure-limited, and time-cycled Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 27
- 26. Pressure Support • usedto augment a patient’s breathing effort by reducing the airflow resistance during spontaneous breathing (the artificial airway, ventilator circuit, and secretions) • Pressure support is available in modes of ventilation that allows spontaneous breathing (e.g., SIMV, PSV). • PS level must be adjusted on an as-needed basis depending on the changing conditions that alter the PIP and Pplat Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 28
- 27. CONTROLLED MANDATORY VENTILATION (CMV) •continuous mandatory ventilation or control mode, the ventilator delivers the preset tidal volume at a time-triggered frequency Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 29
- 28. • Indications forControl Mode (1)tetanus or other seizure activities that interrupt the delivery of mechanical ventilation (2)complete rest for the patient typically for a period of 24 hours (3)patients with a crushed chest injury in which spontaneous inspiratory efforts produce significant paradoxical chest wall movement [email protected] m 30
- 29. • Complication ofCMV – In a sedated or apneic patient, potential for apnea and hypoxia if the patient should become disconnected from the ventilator or the ventilator should fail to operate. – rapid disuse atrophy of diaphragm fibers – prolonged mechanical ventilation leads to diaphragmatic oxidative injury, elevated proteolysis, and reduced function of the diaphragm [email protected] m 31
- 30. How to set(Inputs) • Mode: CMV • TV: 360ml – Given weight: 60kg • BUR: 16 breaths/ min • Minute ventilation: TV x BUR • Peak flow: 60 • FiO2: 100% initially [email protected] m 32
- 31. ASSIST/CONTROL (AC) • Themandatory mechanical breaths may be either patient-triggered by the patient’s spontaneous inspiratory efforts (assist) or time-triggered by a preset frequency • Inspiration in the AC mode is terminated by volume cycling. When the preset tidal volume is delivered, the ventilator is cycled to expiration. • provide full ventilatory support for patients when they are first placed on mechanical ventilation Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 33
- 32. Clinical Application ofMechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 34
- 33. Indications for ACMode • patients with stable respiratory drive and can therefore trigger the ventilator into inspiration. Advantages of AC Mode • patient’s work of breathing requirement is very small • allows the patient to control the frequency and therefore the minute volume required to normalize the patient’s PaCO2 Complications of AC Mode • alveolar hyperventilation (respiratory alkalosis). Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 35
- 34. SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION(SIMV) • ventilator delivers either assisted breaths to the patient at the beginning of a spontaneous breath or time-triggered mandatory breaths • mandatory breaths are synchronized with the patient’s spontaneous breathing efforts so as to avoid breath stacking • Spontaneous frequency and tidal volume taken by the patient in the SIMV mode are totally dependent on the patient’s breathing effort. Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 36
- 35. Clinical Application ofMechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 37
- 36. Indications for SIMVMode – The primary indication for SIMV is to provide partial ventilatory support to the patient. Advantages of SIMV Mode (1) maintains respiratory muscle strength/avoids muscle atrophy, (2) reduces ventilation to perfusion mismatch, (3) decreases mean airway pressure, and (4) facilitates weaning. . Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 38
- 37. Complications of SIMVMode – The desire to wean the patient too rapidly, leading first to a high work of spontaneous breathing and ultimately to muscle fatigue and weaning failure https://www.uptodate.com/contents/modes-of-mechanicalventilation [email protected] m 39
- 38. PRESSURE SUPPORT VENTILATION (PSV) •lower the work of spontaneous breathing and augment a patient’s spontaneous tidal volume • patient-triggered, pressure-limited, and flow- cycled. • PSV + SIMV, significantly lowers the oxygen consumption requirement presumably due to the reduced work of breathing (1) increases the patient’s spontaneous tidal volume, (2) decreases the patient’s spontaneous frequency Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 40
- 39. • Pressure-supported breathsare considered spontaneous because (1)they are patient-triggered, (2)the tidal volume varies with the patient’s inspiratory flow demand, (3)inspiration lasts only for as long as the patient actively inspires, and (4)inspiration is terminated when the patient’s inspiratory flow demand decreases to a preset minimal value. Clinical Application of Mechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 41
- 40. Clinical Application ofMechanical Ventilation, Fourth Edition by David W. Chang [email protected] m 42
- 41. Indication for PSV •weaning from mechanical ventilation Disadvantages • Each breath must be initiated by the patient. Central apnea may occur if the respiratory drive is depressed due to sedatives, critical illness, or hypocapnia due to excessive ventilation • PSV is associated with poorer sleep than AC • Relatively high levels of pressure support (>20 cm H2O) are required to prevent alveolar collapse (which can lead to cyclic atelectasis and ventilator-associated lung injury) https://www.uptodate.com/contents/modes-of-mechanicalventilation [email protected] m 43
- 42. CONTINUOUS POSITIVE AIRWAY PRESSURE(CPAP) • delivery of a continuous level of positive airway pressure. • It is functionally similar to PEEP. • The ventilator does not cycle during CPAP, no additional pressure above the level of CPAP is provided, and patients must initiate all breaths. • most commonly used in the management of – sleep related breathing disorders, – cardiogenic pulmonary edema, and – obesity hypoventilation syndrome • CPAP may be given via a face mask, nasal mask, or endotracheal tube. https://www.uptodate.com/contents/modes-of-mechanicalventilation [email protected] m 44
- 43.
- 44. Thank you Be thechange you wish to see in this world - Mahatma Gandhi [email protected] m 46
Editor's Notes
- #11 There are at least 23 modes of ventilation available in different ventilators. Two or more of these modes are often used together to achieve certain desired effects. For example, spontaneous plus PEEP is the same as CPAP, and it is used to oxygenate a patient who has adequate spontaneous ventilation. SIMV may be used with PSV to provide mechanical ventilation and reduce the work of spontaneous breathing.
- #12 The primary reason for using lower tidal volumes (i.e., permissive hypercapnia) is to minimize the airway pressures and the risk of barotrauma use of low tidal volume ventilation may lead to complications such as acute hypercapnia, increased deadspace ventilation and work of breathing, dyspnea, severe acidosis, and atelectasis
- #13 The initial frequency setting of 10 to 12/min and the calculation shown above are based on the assumption that both CO2 production and physiologic deadspace are normal. If the CO2 production is elevated (e.g., due to an increase of metabolic rate) or the physiologic deadspace is increased (e.g., due to a decrease of pulmonary perfusion), the minute volume required to normalize the PaCO2 will need to be increased. Since increasing the tidal volume results in higher airway pressures on a volume-limited ventilator, it is usually more appropriate to increase the minute volume by increasing the ventilator frequency.
- #14 between 80 and 100 mm Hg (lower for patients with chronic CO2 retention).
- #19 increases both peak inspiratory pressures and mean airway pressures PEEP greater than 10 cm H2O (or mean airway pressure .30 cm H2O, peak inspiratory pressure .50 cm H2O) is associated with an increased incidence of barotrauma.
- #22 auto-PEEP present when the end-expiratory pressure does not return to baseline pressure refractory hypoxemia in ARDS patients with very low compliance. But it should not be the initial I:E setting since reverse I:E ratio has its inherent cardiovascular complications. Inverse I:E ratio should be tried only after traditional strategies have failed to improve a patient’s ventilation and oxygenation status
- #25 A trigger sensitivity of -1 to -3 cm H2O is typically set, which means that ventilator-assisted breaths will be triggered when the alveolar pressure decreases to 1 to 3 cm H2O below atmospheric pressure. the trigger sensitivity is usually set at 2 L/min, which means that ventilator-assisted breaths will be triggered once the patient's inspiratory effort generates a flow of 2 L/min. flow triggering is often preferred because it is associated with less inspiratory effort in several modes of ventilation, even though the effect is usually small
- #29 The initial pressure support level can be calculated as follows. PS level = [(PIP - Pplat)/Vmach] X Vspon PS level: Initial pressure support ventilation setting PIP: Peak inspiratory pressure (20-35cmH20 never be higher than 40) Pplat: Plateau pressure Peak inspiratory flow rate –fastest flow rate noted during the inspiratory cycle normal 30 to 40L/min (60 to 120) # vent: Inspiratory flow of ventilator, in L/min Vspon: Inspiratory flow during spontaneous breathing in L/min (obtained via flow/time graphic or estimated to be 500 mL/sec or 30 L/min)
- #31 with sedation and neuromuscular block
- #32 One study shows that a combination of 18 to 69 hours of complete diaphragmatic inactivity during mechanical ventilation results in marked atrophy of human diaphragm myofibers (Levine et al., 2008)
- #36 (a stable spontaneous frequency of at least 10 to 12/min)
- #38 For example, if the SIMV mandatory frequency is set at 10/min, then the ventilator would time-trigger a breath every 6 sec if the patient is not attempting to inspire spontaneously. However, if the patient is breathing spontaneously between the mandatory breaths, and if by random chance, the patient begins to inspire just prior to the point at which the ventilator would be expected to time-trigger, then the ventilator senses this spontaneous effort and delivers the mandatory breath as an assisted patient-triggered breath. The mandatory breath, whether time- or patienttriggered, is controlled by all applicable mechanical tidal volume settings.
- #39 Mean airway pressure Transpulmonary pressure deff between alveolar and pleural pressure 5 to 10 cmH20