1. Pulmonary atelectasis in anaesthesia and critical care
Damian Laba

2. Types: Obstructive – tumor, mucus plug, FB Non-obstructive
-Compressive – tumor, bullae, air trapping
-Passive/relaxation –parietal and visceral pleaura
-Adhesive -surfactant
-Cicatrizing – scar
Risks: Obesity, lung disease, smoking, pregnancy

3. Atelectasis related to GA
Common
Critically ill
Mechanisms
-Compression: FRC, relaxant, GA, surgical manipulation
+obesity, laparoscopy, OLV
-Absorption
occlusion or high Fi02
-Inflammatory response – ALI, neutrophil activation, fluid, mediators
-Surfactant depletion- smoke inhalation, Laplace’s law

4. Pathophysiological effects of atelectasis
Decreased compliance
- Less effective pressure –volume curve , increase WOB
Impaired oxygenation
-V/Q mismatch
Increased pulmonary vascular resistance
-hypoxic pulmonary vasoconstriction

5. Clinical presentation
Asymtomatic
Non-productive cough
Hypoxia/Respiratory failure
PE: chest expansion, dullness, no breath sounds, trachea
Investigations:
CXR – direct and indirect signs CT US

6. Total lung collapse due to compression from pleural effusion

7. Total obstruction, white out of Rt lung

8. RUL collapse –elevation Rt hilum, horizontal fissure

10. RML collapse – often missed, loss Rt heart border

12. RLL collapse – obliteration Rt hemidiaphragm

14. LUL collapse, veil-like opacity, trachea to Lt, Luftsichel sign

15. Displacement of fissure

16. Increase retrocardiac opacity

17. Lt hemidiaphragm is lost posteriorly

18. Hounsfield units

19. Hepatization of lungs

20. Management Prevention: Identifying high-risk patients physiotherapy,
bronchodilators,
cessation of smoking and
antibiotics when indicated, at least 5–7 days before operation for elective surgery.

21. Baseline X-rays, blood gases, and lung function tests for patients with moderate to severe respiratory and cardiovascular disease for more major procedures.
Lung function test are not recommended as part of routine preoperative for ASA I with no comorbidities undergoing surgery of any severity.

22. On Inductions
FiO2 0.8
Recruitments
CPAP

23. Maintaince PEEP Recruitments:
Vital capacity manoeuvre using an inflation pressure of 40 cmH2O sustained for 10–15 s.
2) Increasing PEEP to 15 cm H2O and then increasing tidal volumes to achieve peak inspiratory pressure of 40 cm H2O for 10 breaths before then returning to standard ventilator settings.

24. Post op
Pain control
CPAP
Deep breath exercise
physiotherapy

25. ITU settings Ventilation strategies: CPAP PEEP Vt 6-8 ml/kg
P plateau < 35 cmH2O
Recruitments
FiO2
? HFOV

26. Other strategies which may be used in the management of artificial ventilation in patients with atelectasis. Prone position Promotes ventilation–perfusion matching, increase FRC, decrease shunt Kinetic bed (40 degrees rotation on each side with pause of 10 min on each side and 5 min in the supine position) Prevents collection of secretions, ventilator-associated pneumonia, redistribution of pressure to allow lung expansion Chest physiotherapy Aids airway clearance and improves ventilation Bronchoscopy Aids airway clearance in patients with poor cough, e.g. neuromuscular disease Mucolytics or Dnase Clears tenacious secretions, good results in paediatrics Surfactant Surface tension to allow alveoli stability and prevent collapse Fluorocarbons Facilitates lung recruitment by separating adherent lung surfaces by virtue of their low equilibrium surface tension and positive spreading coefficient

27. Conclusions:
Atelectasis common cause of hypoxia or respiratory failure in anaesthesia and ITU settings
Prevention better than cure
Timely diagnosis and management is crucial for good outcome

28. Thank you Contin Educ Anaesth Crit Care Pain (2014) 14 (5): 236-245.
First published online: December 23, 2013