More Related Content Similar to Acute respiratory failure (20) More from salaheldin abusin (20) Acute respiratory failure1. ACUTE RESPIRATORY FAILURE
Ihab B Abdalrahman, MBBS, MD, ABIM, SSBB
Ihab Tarawa
Consultant of Acute Care Medicine, Soba University Hospital
10/2/2012 1
4. CO2 O2
Ihab Tarawa 10/2/2012 4
5. 1,2,3
Bottom line of the respiratory system is to
Let oxygen in,
And carbon dioxide out.
Ihab Tarawa 10/2/2012 5
6. Definitions
acute respiratory failure occurs when:
pulmonary system is no longer able to meet the
metabolic demands of the body
hypoxaemic respiratory failure:
PaO2 8 kPa when breathing room air
hypercapnic respiratory failure:
PaCO2 6.7 kPa
Ihab Tarawa 10/2/2012 6
7. Oxygen in
Depends on
Ventilation
PAO2
Perfusion
Ventilation-perfusion matching
Diffusing capacity
Ihab Tarawa 10/2/2012 7
8. PAO2
The alveolar pressure is equal to the sum of
the partial pressures of the gases within the
alveolus.
The partial pressure of each gas is
proportional to the concentration of the gas.
Ihab Tarawa 10/2/2012 8
9. Oxygen
Carbon
dioxide
Water
vapour
Nitrogen
Alveolarpressure PAO2 PACO2 PAH2O PAN2
Ihab Tarawa 10/2/2012 9
10. Oxygen
Carbon
dioxide
Water
vapour
Nitrogen
Alveolarpressure PAO2 PACO2 PAH2O PAN2
Ihab Tarawa 10/2/2012 10
11. Oxygen
Carbon
dioxide
Water
vapour
Nitrogen
Alveolarpressure PAO2 PACO2 PAH2O PAN2
Ihab Tarawa 10/2/2012 11
12. Oxygen in
Depends on
PAO2
FIO2
Alveolar pressure
PACO2
Ventilation
Ventilation-perfusion matching
Perfusion
Diffusing capacity
Ihab Tarawa 10/2/2012 12
14. Carbon dioxide out
Largely dependent on alveolar ventilation
Alveolar ventilation RR x (V - V ) T D
Anatomical dead space constant but
physiological dead space depends on ventilation-
perfusion matching
Ihab Tarawa 10/2/2012 14
15. Carbon dioxide out
Respiratory rate
Tidal volume
Ventilation-perfusion matching
Ihab Tarawa 10/2/2012 15
18. Pathophysiology
Low inspired Po2
Although, in theory, acute respiratory failure may
result from a low inspired PO2 this is rarely a
problem in Intensive Care except in locations at
high altitude.
Ihab Tarawa 10/2/2012 18
20. Oxygen
Carbon
dioxide
Water
vapour
Nitrogen
Alveolarpressure PAO2 PACO2 PAH2O PAN2
Ihab Tarawa 10/2/2012 20
21. Hypoventilation
PAO2=9.74 kPa
PACO2=10 kPa
75%
92%
Ihab Tarawa 10/2/2012 21
22. Brainstem
Spinal cord
Airway Nerve root
Lung Nerve
Pleura
Neuromuscular
Chest wall junction
Respiratory
muscle
Sites at which disease may cause hypoventilation
Ihab Tarawa 10/2/2012 22
23. Brainstem
Spinal cord
Airway Nerve root
Lung Nerve
Pleura
Neuromuscular
Chest wall junction
Respiratory
muscle
Sites at which disease may cause hypoventilation
Ihab Tarawa 10/2/2012 23
24. Pathophysiology
Low inspired oxygen concentration
Hypoventilation
Shunting
Dead space ventilation
Diffusion abnormality
Ihab Tarawa 10/2/2012 24
25. Shunt
Ihab Tarawa 10/2/2012 25
27. hypoxic vasoconstriction
↓perfusion to non-ventilated alveoli
↑perfusion to ventilated alveoli,
↓ magnitude of the shunt
↑and increasing the arterial saturation
75% 75%
100% 75%
90%
Ihab Tarawa 10/2/2012 27
28. Shunting
Intra-pulmonary
Pneumonia
Pulmonary oedema
Atelectasis
Collapse
Pulmonary haemorrhage or contusion
Intra-cardiac
Any cause of right to left shunt
eg Fallot’s, Eisenmenger,
Pulmonary hypertension with patent foramen ovale
Ihab Tarawa 10/2/2012 28
29. Pathophysiology
Low inspired oxygen concentration
Hypoventilation
Shunting
Dead space ventilation
Diffusion abnormality
Ihab Tarawa 10/2/2012 29
31. Pathophysiology
Low inspired oxygen concentration
Hypoventilation
Shunting
Dead space ventilation
Diffusion abnormality
Ihab Tarawa 10/2/2012 31
33. Diffusion abnormalities.
These can result from a failure of diffusion
across the alveolar membrane
or a reduction in the number of alveoli
resulting in a reduction in the alveolar surface
area.
Causes include ARDS and fibrotic lung
disease
Ihab Tarawa 10/2/2012 33
36. Bottom line of the respiratory system is to let
oxygen in and CO2 out.
Some sensors will go off
Hypoxia
Acidosis
Ihab Tarawa 10/2/2012 36
41. Point of making a difference
Coming for help
Or coming with a coffin
Ihab Tarawa 10/2/2012 41
44. If we wait for the
patient to become
cyanosed
Ihab Tarawa 10/2/2012 44
46. The oxygen content of blood is mainly
dependent on:
the haemoglobin saturation,
with the a very small contribution from dissolved
oxygen.
Ihab Tarawa 10/2/2012 46
47. Oxygen delivery
O2 delivery Cardiac output O2 content 10
O2 content O2 saturation Hb 1.37 0.003 PaO2
Ihab Tarawa 10/2/2012 47
49. 123
80
40
87%
HR=95
Ihab Tarawa 10/2/2012 49
50. Sources of error
Poor peripheral perfusion
Poorly adherent/positioned probe
False nails or nail varnish
Lipaemia
Bright ambient light
Excessive motion
Carboxyhaemoglobin or methaemoglobin
Ihab Tarawa 10/2/2012 50
52. Summary
worry if
RR > 30/min (or < 8/min)
unable to speak 1/2 sentence without pausing
agitated, confused or comatose
cyanosed or SpO2 < 90%
deteriorating despite therapy
remember
normal SpO2 does not mean severe ventilatory problems are not
present
Ihab Tarawa 10/2/2012 52
54. Treatment
Treat the cause
Supportive treatment
Oxygen therapy
CPAP
Mechanical ventilation
Ihab Tarawa 10/2/2012 54
60. Lung compliance and FRC
reduces work of breathing
Volume
Pressure Ihab Tarawa 10/2/2012 60
64. Ventilate?
Severity of respiratory failure
Cardiopulmonary reserve
Adequacy of compensation
Ventilatory requirement
Ihab Tarawa 10/2/2012 64
65. Ventilate?
Severity of respiratory failure
Cardiopulmonary reserve
Adequacy of compensation
Ventilatory requirement
Expected speed of response
Underlying disease
Treatment already given
Ihab Tarawa 10/2/2012 65
66. Ventilate?
Severity of respiratory failure
Cardiopulmonary reserve
Adequacy of compensation
Ventilatory requirement
Expected speed of response
Underlying disease
Treatment already given
Risks of mechanical ventilation
Ihab Tarawa 10/2/2012 66
67. Ventilate?
Severity of respiratory failure
Cardiopulmonary reserve
Adequacy of compensation
Ventilatory requirement
Expected speed of response
Underlying disease
Treatment already given
Risks of mechanical ventilation
Non-respiratory indication for intubation
Ihab Tarawa 10/2/2012 67
68. Ventilate?
43 year old male
Community acquired pneumonia
Day 1 of antibiotics
PaO2 8 kPa (60 mmHg), PaCO2 4 kPa (30
mmHg), pH 7.15 on 15 l/min O2 via reservoir
facemask
Respiratory rate 35/min
Agitated
Ihab Tarawa 10/2/2012 68
69. Yes
43 year old male
Community acquired pneumonia
Day 1 of antibiotics
PaO2 8 kPa (60 mmHg), PaCO2 4 kPa (30
mmHg), pH 7.15 on 15 l/min O2 via reservoir
facemask
Respiratory rate 35/min
Agitated
Ihab Tarawa 10/2/2012 69
70. Yes
43 year old male
Community acquired pneumonia
Day 1 of antibiotics
PaO2 8 kPa (60 mmHg), PaCO2 4 kPa (30
mmHg), pH 7.15 on 15 l/min O2 via reservoir
facemask O2
O2
Respiratory rate 35/min
Agitated
Ihab Tarawa 10/2/2012 70
71. Yes
43 year old male
Community acquired pneumonia
Day 1 of antibiotics
PaO2 8 kPa (60 mmHg), PaCO2 4 kPa (30
mmHg), pH 7.15 on 15 l/min O2 via reservoir
facemask
Respiratory rate 35/min
Agitated
Ihab Tarawa 10/2/2012 71
72. Yes
43 year old male
Community acquired pneumonia
Day 1 of antibiotics
PaO2 8 kPa (60 mmHg), PaCO2 4 kPa (30
mmHg), pH 7.15 on 15 l/min O2 via reservoir
facemask
Respiratory rate 35/min
Agitated
Ihab Tarawa 10/2/2012 72
73. Yes
43 year old male
Community acquired pneumonia
Day 1 of antibiotics
PaO2 8 kPa (60 mmHg), PaCO2 4 kPa (30
mmHg), pH 7.15 on 15 l/min O2 via reservoir
facemask
Respiratory rate 35/min
Agitated
Ihab Tarawa 10/2/2012 73
74. Ventilate?
24 year old woman
Presents to A&E with acute asthma
SOB for 2 days
Salbutamol inhaler, no steroids
PFR 60 L/min, HR 105/min
pH 7.25 PaCO2 6.8 kPa (51 mmHg), PaO2 42 kPa
(315 mmHg) on FiO2 0.6
RR 35/min
Alert
Ihab Tarawa 10/2/2012 74
75. No
24 year old woman
Presents to A&E with acute asthma
SOB for 2 days
Salbutamol inhaler, no steroids
PFR 60 L/min, HR 105/min
pH 7.25 PaCO2 6.8 kPa (51 mmHg), PaO2 42 kPa
(315 mmHg) on FiO2 0.6
RR 35/min
Alert
Ihab Tarawa 10/2/2012 75
76. No
24 year old woman
Presents to A&E with acute asthma
SOB for 2 days
Salbutamol inhaler, no steroids
PFR 60 L/min, HR 105/min
pH 7.25 PaCO2 6.8 kPa (51 mmHg), PaO2 42 kPa
(315 mmHg) on FiO2 0.6
RR 35/min
Alert
Ihab Tarawa 10/2/2012 76
77. No
24 year old woman
Presents to A&E with acute asthma
SOB for 2 days
Salbutamol inhaler, no steroids
PFR 60 L/min, HR 105/min
pH 7.25 PaCO2 6.8 kPa (51 mmHg), PaO2 42 kPa
(315 mmHg) on FiO2 0.6
RR 35/min
Alert
Ihab Tarawa 10/2/2012 77
78. No
24 year old woman
Presents to A&E with acute asthma
SOB for 2 days
Salbutamol inhaler, no steroids
PFR 60 L/min, HR 105/min
pH 7.25 PaCO2 6.8 kPa (51 mmHg), PaO2 42 kPa
(315 mmHg) on FiO2 0.6
RR 35/min
Alert
Ihab Tarawa 10/2/2012 78
79. No
24 year old woman
Presents to A&E with acute asthma
SOB for 2 days
Salbutamol inhaler, no steroids
PFR 60 L/min, HR 105/min
pH 7.25 PaCO2 6.8 kPa (51 mmHg), PaO2 42 kPa
(315 mmHg) on FiO2 0.6
RR 35/min
Alert
Ihab Tarawa 10/2/2012 79
80. No
24 year old woman
Presents to A&E with acute asthma
SOB for 2 days
Salbutamol inhaler, no steroids
PFR 60 L/min, HR 105/min
pH 7.25 PaCO2 6.8 kPa (51 mmHg), PaO2 42 kPa
(315 mmHg) on FiO2 0.6
RR 35/min
Alert
Ihab Tarawa 10/2/2012 80
81. Pathway
Airway patent
Secure airway
Patient breathing
Ventilat
Is he hypoxic
Ihab Tarawa 10/2/2012 81
82. Hypoxic
Yes No
Acidosis
Shock
PE
Asthma
Pumonary
edema
Anxiety
Ihab Tarawa 10/2/2012 82
83. Hypoxic
Pco2
Low Pco2
High /normal
pneumonia
ARDS
Pulmonary
edema
Aspiration
PE
pneumothorax
Ihab Tarawa 10/2/2012 83
84. Hypoxic
Pco2
Low Pco2
High /normal
Normal A-a High A-a
gradient gradient
Breathing Breathing Fatigue from
hard normally hypoxia
Acute on
Asthma CND
chronic
COPD Drugs
PE
Ihab Tarawa 10/2/2012 84