1. N Engl J Med. 2013 Aug 1;369(5):428-37
Dr Peter Sherren

2. Background
• Ventilator-associated lung injury and biotrauma
• Barotrauma/Volutrauma
• Atelectasis
• Hyperoxia
• Low vs high tidal volume ventilation in ALI/ARDS.
N Engl J Med. 2000 May 4;342(18):1301-8.
• Lung protective ventilation in the critically ill
without ARDS. JAMA 2012; 308: 1651-1659.
• Relevant to perioperative ventilation?

3. Current practice
• High tidal volume/zero PEEP perioperative
ventilation N Engl J Med. 1963 Nov 7;269:991-6.
• Only historical practice? Anaesthesia. 2012 Sep;67(9):9991008.
• Problem just in theatres? BMJ. 2012 Apr 5;344:e2124.

4. Study question relevant and
original?

5. Hypothesis
Prophylactic lung-protective ventilation that
combines low tidal volumes, PEEP, and
recruitment manoeuvres will improve outcomes
after abdominal surgery

6. Study design
• Multi-centre RCT (Double blind, stratified, parallel
groups)
• Pts undergoing major elective abdominal surgery
(>2Hrs), >40yrs old, Post-operative risk index for
pulmonary complications >2.
• Exclusion criteria – IPPV/respiratory failure/sepsis
within 2 weeks, BMI>35, emergency or thoracic
surgery or neuromuscular disease.
• Randomised to
• TV 6-8 mL/kg IBW; PEEP 6-8 cm H2O; recruitment manoeuvres every
30 minutes.
• TV 10-12ml/kg; No PEEP or recruitment manoeuvres

7. Outcome measures
• Primary Outcome - Composite measure of major
pulmonary and extra-pulmonary complications
within 7 days.
• Multiple secondary outcomes – Gas exchange,
adverse ventilation related events, unexpected
ICU admission, ICU/hospital LOS, ARDS……

8. Statistics
• Assumed 20% postoperative complication rate.
Arch Surg 2003;138:596-602.
• 400 pts need to detect a 50% change in
complication rate. Power of 80% and α level
0.05.
• Modified intention-to-treat population.
• Appropriate descriptive and comparative
statistics used

9. Results
• 1803 underwent surgery over the 18 month period.
601 screened and 400 randomised.
• Well matched groups
• Major postoperative complications occurred in
27.5% vs 10.5% of those receiving high vs low tidal
volume ventilation (P=0.001).
• 5% of patients in the protective ventilation group
required postoperative ventilatory assistance for
acute respiratory failure vs. 17% in the control group
(P=0.001),

12. Authors’ conclusion
“As compared with a practice of non-protective
mechanical ventilation, the use of a lungprotective ventilation strategy in intermediate-risk
and high-risk patients undergoing major
abdominal surgery was associated with improved
clinical outcomes and reduced health care
utilisation”

13. Limitations
• Authors – No standardised fluid administration
and criteria for initiation of NIV.
• Other - Ventilatory parameters in the control
group not representative of standard anaesthetic
practice?

14. Will it change our practice?

15. Questions?