1. BASIC VENTILATION
Dr David Maritz

2. Mechanical ventilation. Emergency Med Clin N Am. 26 (2008) 849 - 862

3. Introduction
Emergency room-vs-ICU-vs-operating room
Trouble shooting in ICU
Terminology!
Specific scenarios

4. Introduction Why is the patient on the ventilator?
Is the patient breathing spontaneously?
Who is doing the greater work of breathing?
Volume or pressure targeted strategy?
Dual controlled mode?
What is the set respiratory rate?
What is the total respiratory rate?
What is the set extrinsic / applied PEEP?
Is there intrinsic / auto PEEP?
What is the I:E ratio, flow rate, trigger mode?
What do the respiratory graphics indicate?

5. Introduction
Volume targeted ( volume cycled , volume assist / control)
Pressure targeted
Dual

6. Introduction
RR x Vt = MV
Intubated for airway protection
Septic / severe acidosis
ALI / ARDS
Other scanarios

7. Extrinsic PEEP – offset loss of FRC Caution in:
Introduction
Adjust FiO2
Extrinsic PEEP – offset loss of FRC
Caution in:
Elevated ICP
Unilateral lung process
Hypotension
Hypovolaemia
Pulmonary embolism

9. Flow waveform – decelerate
Introduction
Flow waveform – decelerate
Optimise recruitment
Trigger mode – detects pressure or flow gradient
Patient triggers ventilator
Too high – increased work
Too low – auto trigger
1 – 3 cmH2O

10. Spontaneous breathing
Supported by pressure support ventilation (PSV)
Clinician sets FiO2 / PEEP
Patient sets RR / flow rate
VT dictated by PS / patient effort / lung compliance
Back up apnea rate

11. Volume targeted mode
Ventilator will generate necessary driving pressure to reach the targeted volume
Beware auto / intrinsic PEEP ( breath stacking)
Therefore progressive air trapping

14. Pressure targeted mode
Ventilator generates preset inspiratory pressure
Vt function of respiratory mechanics
Better pressure distribution
Any change in system compliance / resistance will affect Vt

17. Asthma / COPD Volume depleted Hyperinflation (auto-PEEP)
8-10 breaths per minute
Decrease inspiratory time / increase expiratory time
Vt 6-7 ml/kg
Increase flow rate (80-100l/min)
Square wave form
Permissive hypercapnia
Sedation / paralyze
Sudden hypotension:
Disconnect fom ventilator
Tension pneumo

22. Acute lung injury / ARDS
PaO2/FiO2 < 200
Bilat pulmonary infiltrates
Wedge presssure < 18mmHg
ALI:
PaO2 / FiO2 < 300
Lung protection ventilation:
Vt 4-6ml/kg
Higher resp rates
Plateau pressures < 30cmH2O
Permissive hypercapnia
Volume targeted
Sedation / temp paralysis

24. Troubleshooting Respiratory distress in ventilated patients:
Anxiety
Pain
Inadequate ventilator settings
ETT malfunction
Pulmonary parenchymal process
Extrapulmonary process
Tension pneumotghorax
Severe auto-PEEP
Stable – vs - unstable

25. Hemodynamically stable
Systematic approach
Focused history / exam
Check ventilator / circuit
Respiratory mechanics ( Peak and Plateau pressures)
CXR
Bedside ultrasound

26. Problem with airflow

28. Decreased lung compliance

30. Hemodynamically unstable
Remove from ventilator / hand ventilated 100% O2 (beware if high PEEP)
Severe auto-PEEP:
Do not hyperventilate
Disconnect from ventilator / compress chest
Tension pneumothorax:
Both sides!
Check settings / circuit / ETT etc
Reintubation – DIFFICULT AIRWAY

31. Noninvasive positive pressure ventilation

32. Noninvasive positive pressure ventilation in the emergency department
Noninvasive positive pressure ventilation in the emergency department. Emerg Med Clin N Am. 26 (2008)

33. Terminology!!

34. Definition CPAP a separate entity! NPPV / NIPPV / Bilevel pressure
Continuous positive pressure
Tight fitting facemask
Spontaneous breathing
NPPV / NIPPV / Bilevel pressure
Inspiratory pressure (IPAP / inspiratory positive airway pressure)
End expiratory positive pressure (EPAP / expiratory positive airway pressure)
Breaths triggered by patient (back up rate)

35. Rationale Avoid complications of invasive ventilation
Avoid ICU admissions
Reduce costs
Improve mortality

36. Advantages of NIV Disadvantages
    Preservation of airway defence mechanism   Early ventilatory support   Intermittent ventilation   Patient can eat, drink and communicate   Ease of application and removal   Patient can cooperate with physiotherapy   Improved patient comfort   Reduced sedation requirements   Avoidance of complications of intubation   Ventilation outside hospital setting possible
Disadvantages
    Mask is uncomfortable/claustrophobic   Time consuming for medical and nursing staff   Airway is not protected   No direct access to bronchial tree for suction

37. Pathophysiology CPAP – increases alveolar recruitement NPPV / bilevel
= extrinsic PEEP and EPAP
Negates intrinsic PEEP ( auto PEEP / dynamic hyperinflation)
Increases intrathoracic pressure
NPPV / bilevel
IPAP = pressure support
Rest during inspiration

38. Indications Acute exacerbations COPD Asthma Acute pulmonary oedema
Hypoxemic respiratory failure
Immunosuppressed patients
Do not intubate patients
Facilitation of weaning and extubation

39. Exacerbation COPD
Initiate early
Alongside with medical therapy

40. Asthma
Extrinsic PEEP offsets intrinsic PEEP

41. Acute cardiogenic pulmonary edema
CPAP and NPPV improve symptoms
Neither improves mortality
May decrease intubation rates

42. Hypoxic respiratory failure
Mixed data
Further studies needed

43. Feasibility Very little data on safety
Failure of NPPV associated with:
GCS < 13
RR > 20 after 1 hour
pH < 7.35 after hour

44. Initiation No standard approach High-low approach: Low-high approach:
High IPAP (20-25cmH2O)
Low-high approach:
Low IPAP (8-10cmH2O)
EPAP 3-4cmH2O
Significant autopeep / PEEPi - EPAP 4-8cmH2O
Titrate FiO2
Adjust EPAP

46. Summary Reversible conditions Bridging therapy
Close monitoring / follow up