Basics of mechanical ventilation
- 2. OBJECTIVES Understanding of ā¢ Basic Variables. ā¢ Ventilator Graphs. ā¢ Types of Ventilator Modes. ā¢ Ventilation in Cardiac Surgery. 2
- 3. BASIC VARIABLES o Resp rate o Pressure o Volume o PEEP o Flow o Inspiratory time/ Inspiratory: Expiratory time
- 6. TYPES OF BREATHS A. Mandatory/Control B. Assisted Breath C. Spontaneous Breath
- 8. TYPES OF VENTILATOR MODES Pressure Control Volume Control
- 9. TYPES OF VENTILATOR MODES ā¢ CMV (PC/VC) ā¢ AC (PC/VC) ā¢ SIMV (PC/VC) ā¢ SPN-CPAP/PS ā¢ VC-MMV ā¢ PC-BIPAP ā¢ SPN-PPS ā¢ PC-PSV ā¢ PC-APRV
- 10. CONTINUOUS MANDATORY VENTILATION Features ā¢ Clinician-set mandatory breath rate ā¢ Mandatory breaths will be ventilator-triggered Clinician-Set Parameters ā¢ Mandatory breath rate ā¢ Breath type ā¢ VC ā¢ PC ā¢ Fractional inspired O2 concentration (FIO2) ā¢ Positive end-expiratory pressure (PEEP)
- 12. ASSIST CONTROL Features ā¢ Clinician-set mandatory breath rate ā¢ Mandatory breaths may be patient-triggered or ventilator-triggered ā¢ The patient may trigger any number of additional (spontaneous) breaths ā¢ Mandatory and spontaneous breaths are identical Clinician-Set Parameters ā¢ Mandatory breath rate ā¢ Breath type ā¢ VC ā¢ PC ā¢ Fractional inspired O2 concentration (FIO2) ā¢ Positive end-expiratory pressure (PEEP)
- 14. SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION Features ā¢ Clinician-set mandatory breath rate ā¢ Mandatory breaths may be patient-triggered or ventilator-triggered ā¢ The patient may trigger any number of additional (spontaneous) breaths ā¢ Mandatory and spontaneous breaths are always different Clinician-Set Parameters ā¢ Mandatory breath rate ā¢ Mandatory breath type ā¢ VC ā¢ PC ā¢ Spontaneous breath type ā¢ PS ā¢ FIO2 ā¢ PEEP
- 16. SPONTANEOUS-CONTINUOUS POSITIVE AIRWAY PRESSURE Features ā¢ No mandatory breaths ā¢ All breaths are spontaneous and patient-triggered Clinician-Set Parameters ā¢ Breath type ā¢ PS ā¢ FIO2 ā¢ PEEP
- 18. INITIAL VENTILATOR SETTINGS FOR POST-OP PATIENTS IN CARDIAC SURGERY ā¢ FiO2: 70ā100%, mode: SIMV. ā¢ Tidal volume: 8ā10mL/kg. ā¢Respiratory rate: 8ā14 breaths/min. ā¢Minute volume: 100ā120mL/kg/min. ā¢PEEP: 5ā7.5cmH2O, ā¢Pressure support: 8ā10 cmH2O. ā¢Inspiratoryāexpiratory ratio: 1:2, ā¢inspiratory flow rate: 30ā60L/min.
- 19. CARDIAC SURGERY ā¢ Any patient can be ventilated safely using SIMV. ā¢ A tidal volume of 8ā10mL/kg helps prevent atelectasis: but excessive tidal volumes risk barotrauma, and can place a borderline LIMA graft under tension as it crosses the upper lobe of the left lung to the LAD. ā¢ A respiratory rate of 8ā14 breaths per minute is adequate for most patients, but patients with higher metabolic demands (shivering, sepsis) may benefit from higher rates which help prevent respiratory acidosis.
- 20. CARDIAC SURGERY ā¢Increasing PEEP to 10cmH2O helps to reverse atelectasis improving oxygenation, but can reduce venous return and MAPs in patients. ā¢Higher levels of PEEP are sometimes used in the hemodynamically stable, bleeding patient to tamponade chest wall bleeding. ā¢The inspiratoryāexpiratory (I:E) ratio is 1:2., allowing optimal peak inspiratory pressures and reducing the risk of air trapping: in selected patients that are diffi cult to oxygenate the intensivist or anesthesiologist will change or even reverse these ratios.
- 21. CARDIAC SURGERY ā¢Patients with COPD benefit from lower respiratory rates and higher tidal volumes, allowing time for the longer expiratory phase, avoiding air trapping (āautoPEEPā) which can cause high intrathoracic pressures, barotrauma, and reduced venous return causing hypotension. ā¢Peak inflation pressures in the adult are usually <30 cmH2O, and the usual inspiratory fl ow rate is 30L/min, higher peak infl ation pressures occur in obesity, active resistance from the patient, or a mechanical obstruction to airfl ow such as bronchospasm, endobronchial intubation or mucus plugging with lobar collapse.
- 22. REFERENCES ļ§ Chikwe, J., Cooke, D.T and Weiss, A. (2013) Oxford Specialist Handbook of Cardiothoracic Surgery, 2nd edn., : Oxford University Press. ļ§ Kreit, J.W. (2017) Mechanical Ventilation: Physiology and Practice, 2nd edn., : Oxford University Press. ļ§ DRAGER () Instructions for use Evita V300, Available at: https://www.draeger.com/Library/Content/evita-v300-ifu-9052995- en.pdf ļ§ icet-nepean () CHEAT SHEETS FOR VENTILATION, Available at: https://www.icetnepean.org/uploads/5/8/5/ 1/58510755/cheat_sheets_for_ventilation_5.pdf.
- 23. THANK YOU