1 / 80

Andrea Vianello S.C. Fisiopatologia Respiratoria Ospedale-Università di Padova

PNEUMOTRIESTE 2016. CONCETTI GENERALI SUI VENTILATORI. Andrea Vianello S.C. Fisiopatologia Respiratoria Ospedale-Università di Padova. RESPIRATORY FAILURE. LUNG FAILURE. PUMP FAILURE. GAS EXCHANGE FAILURE. VENTILATORY FAILURE. HYPERCAPNIA. HYPOXEMIA.

marydcarter
Download Presentation

Andrea Vianello S.C. Fisiopatologia Respiratoria Ospedale-Università di Padova

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. PNEUMOTRIESTE 2016 CONCETTI GENERALI SUI VENTILATORI Andrea Vianello S.C. Fisiopatologia Respiratoria Ospedale-Università di Padova

  2. RESPIRATORY FAILURE LUNG FAILURE PUMP FAILURE GAS EXCHANGE FAILURE VENTILATORY FAILURE HYPERCAPNIA HYPOXEMIA

  3. What’s the point of ventilation? • Deliver O2 to alveoli • Hb binds O2 (small amount dissolved) • CVS transports to tissues to make ATP - do work • Remove CO2 from pulmonary vessels • from tissues - metabolism

  4. Why ventilate?- purposes • To maintain or improve ventilation, & tissue oxygenation. • To decrease the work of breathing & improve patient’s comfort.

  5. When ventilate?- indications • Failure of pulmonary gas exchange • Hypoxaemia: low blood O2 • “Mechanical” failure • Hypercarbia: high blood CO2 • Respiratory muscle fatigue • Need to intubate eg patient unconscious • Others eg • need neuro-muscular paralysis to allow surgery • cardiovascular reasons

  6. Definition: What is it? • Mechanical Ventilation =Machine to ventilate lungs = move air in (+ out) • Several ways to..move air in (IPPV vs others) Intermittent Positive Pressure Ventilation

  7. Definition: What is it? • Mechanical Ventilation =Machine to ventilate lungs = move air in (+ out) • Several ways to..move air in (IPPV vs others) Intermittent Positive Pressure Ventilation • Several ways to connect the ventilator to the patient

  8. Several ways to connect the machine to patient • Oro-tracheal Intubation • Tracheostomy • Non-Invasive Ventilation

  9. Normal breath Normal breath inspiration, awake Lung @ FRC= balance Diaphragm contracts -2cm H20 Chest volume Pleural pressure -7cm H20 Alveolar pressure falls Air moves down pressure gradient to fill lungs

  10. La pompa diaframmatica genera Pgarantendo la ventilazione polmonare, regolata da: • Equazione di moto del Sistema Respiratorio: Pmusc = V / C + V’ x R

  11. Normal breath Normal breath expiration, awake -7cm H20 Diaphragm relaxes Pleural / Chest volume  Pleural pressure rises -2cm H20 Alveolar pressure rises Air moves down pressure gradient out of lungs

  12. Ventilator breath Portableventilator ICU ventilator ICU ventilator

  13. Ventilator breath Ventilator breath inspiration Air blown in 0 cm H20  lung pressure Air moves down pressure gradient to fill lungs +5 to+10 cm H20  Pleural pressure

  14. Il ventilatore sostituisce totalmente o parzialmente la pompa muscolare: • Equazione di moto del Sistema Respiratorio: Pappl (+ Pmusc) = V / C + V’ x R

  15. Ventilator breath Ventilator breath expiration Similar to spontaneous…ie passive Ventilator stops blowing air in Pressure gradient Alveolus-trachea Air moves out Down gradient  Lung volume

  16. Practicalities • Ventilator settings: • Pressure vs volume • ‘Assist’ vs ‘Control’ • Trigger sensitivity • PEEP?

  17. Practicalities Ventilator settings: Pressure vs volume ‘Assist’ vs ‘Control’ Trigger sensitivity PEEP?

  18. Details: Inspiration Pressure or Volume? • Do you push in.. • A gas at a set pressure? = ‘pressure…..’ • A set volume of gas? = ‘volume….’

  19. Pressure Ventilators • The use of pressure ventilators is increasing in critical care units. • A typical pressure mode delivers a selected gas pressure to the patient early in inspiration, and sustains the pressure throughout the inspiratory phase. • By meeting the patient’s inspiratory flow demand throughout inspiration, patient effort is reduced and comfort increased.

  20. Details: Inspiration Pressure or Volume? Pressure cm H20 Time Pressure cm H20 Time

  21. Although pressure is consistent with these modes, volume is not. • Volume will change with changes in resistance or compliance • Therefore, exhaled tidal volume is the variable to monitor closely. • With pressure modes, the pressure level to be delivered is selected, and with some mode options, rate and inspiratory time are preset as well.

  22. Volume Ventilators • The volume ventilator has been historically used in critical care settings • A respiratory rate, inspiratory time, and tidal volume are selected for the mechanical breaths. • The basic principle of this ventilator is that a designated volume of air is delivered with each breath. • Theamount of pressure required to deliver the set volume depends on : - Patient’s lung compliance - Patient–ventilator resistance factors

  23. Details: Inspiration Pressure or Volume?

  24. Peak Inspiratory Pressure (PIP ) must be monitored in volume modes because it varies from breath to breath 30 Peak Inspiratory Pressure P aw Time (s) cmH2O 1 2 3 -10

  25. Details: Pressure vs Volume in the Acute Setting Secretions hypoventilation Vt preserved partial compensation hypoventilation sensitive insensitive Schönhofer ERS Monograph 2001; 16: 259-73, mod

  26. small leak huge leak Details: leak compensation without leakage with leakage Pressure Vol Pressure Vol Pre-set Mehta et al. Eur Respir J 2001; 17: 259-267

  27. Practicalities Ventilator settings: Pressure vs volume ‘Assist’ vs ‘Control’ Trigger sensitivity PEEP?

  28. Interaction Ventilator Respiratory muscle pump

  29. . . Ventilator Respiratory muscle pump work of breathing spontaneous assisted controlled

  30. Noninvasive mechanical ventilation in acute exacerbation of restrictive thoracic disease Eur Respir Mon 2001; 6:70-73

  31. Practicalities Ventilator settings: Pressure vs volume ‘Assist’ vs ‘Control’ Trigger sensitivity PEEP?

  32. Pressure Flow Volume Time 4 Phases • Inspiratory triggering • Inspiration • Termination • of inspiration • Expiration Nilsestuen et al. Respir Care 2005; 50:202-232

  33. Details: trigger sensitivity trigger asynchrony insensitive trigger sensitive trigger auto- triggering • trigger sensitivity to low • high level of PSV • hypercapnic encephalopathy • sedation • sleep • intrinsic PEEP (COPD) • tubing obstruction • trigger sensitivity to high • resistance changes • tubing leakage • cardiac oscillation

  34. Trigger poco sensibile: allo sforzo inspiratorio non segue l’atto meccanico del respiratore

  35. Pao Pes patient 3 patient 1 patient 2

  36. Trigger troppo sensibile: l’atto meccanico si innesca spontaneamente

  37. Problems: • Increased work of breathing • Need for sedation • „Fighting the ventilator“ • Ventilation-Perfusion-Mismatch • Dynamic hyperinflation • Consequences: • Insufficient ventilation • Withdrawal from NIV • Weaning failure • Prolonged ICU stay • Costs Prognosis ! Asynchrony between patient and ventilator

  38. PSV - pressione inspiratoria - sensibilità trigger - eventuale “rampa” (tempo di raggiungimento PS) L’operatore imposta:  • - pressure-controlled • flow-cycled • patient-triggered Caratteristiche: - > sincronismo paziente-ventilatore  > comfort - possibile graduazione sforzo inspiratorio

  39. lenta media rapida Diversi tipi di rampa

  40. PSV Problemi: • difficoltà di impostazione • livello PS  VT: 6-8ml/Kg; RR: 20-35b/min • P0.1: 2-4 cm H2O • abolizione dissincronismitoraco- addominali • possibile sovrassistenza

  41. A-CV -volume corrente -frequenza respiratoria -rapporto I/E -sensibilità del trigger L’operatore imposta: • volume-controlled • time-cycled • machine e/o patient-triggered (assistito) • pressure-limited (eventuale)  - volume corrente insufflato garantito - rapporto I/E variabile Caratteristiche: - possibile sovrassistenza alcalosi respiratoria - insorgenza di PEEP intrinseca Problemi:

  42. A-CV

  43. Hybrid modes combine the advantages of pressure pre-set and volume pre-set VAPS Volume Assured Pressure Support • Automatic adjustment of inspiratory pressure (range setting) • Target volume set • Measurement of inspiratory pressure and expiratory volume • Calculation of missing inspiratory volume • Increase of inspiratory pressure Assurance of tidal volume + comfort of pressure pre-set

  44. VAPS Volume Assured Pressure Support

  45. VAPS Volume Assured Pressure Support

  46. Storre et al. Chest 2006;130: 815-821

More Related