1. Use of the INVENT system for standardized quantification of clinical preferences towards mechanical ventilation C Allerød 1,2, DS Karbing 1, P Thorgaard 2, S Andreassen 1, S Kjærgaard 2, SE Rees 1 1 : Center for Model-based Medical Decision Support, Aalborg University, Denmark 2 : Anaesthesia and Intensive Care, Region North Jutland, Aalborg Hospital, Aarhus University, Denmark

2. Introduction Several RCTs indicate that low tidal volumes are beneficial in mechanically ventilated patients Large variability in ventilator settings are still seen in the ICU But how well do physicians agree when presented to identical patients? The ARDS Network. N Engl J Med 2000; 342:1301-8. Young et al. Crit Care Med 2004; 32:1260-5. Esteban et al. Am J respir Crit Care Med 2008; 177:170-7

3. Using INVENT for quantifying preferences INVENT: Model-based decision support system for mechanical ventilation –Advice on FiO 2, Vt and f. J Clin Monit Comput 2006; 20:421-9. J Crit Care 2010; 25:367-74.

4. Research questions What is the variability in physicians’ preferences in the same patient? What are physicians’ opinion about other physicians’ advice? What are the physicians’ opinion about INVENT’s advice?

5. Methods Included 10 senior ICU physicians, representing the 4 Danish University Hospitals 10 real patient cases, presented in random order –Reflecting range of respiratory, circulatory and metabolic status in patients with ALI/ARDS Asked to set FiO 2, Vt and f –Assuming correct PEEP and I:E ratio, 70 kg body weight and that model simulations were correct Evaluated and ranked other physicians’, and INVENT’s advice (blinded, and in random case order)

6. Results What is the variability in physicians’ preferences in the same patient? Example: Vt

7. Variability in physicians’ preferences 6 ml/kg 8 ml/kg

8. Variability in physicians’ preferences 6 ml/kg 8 ml/kg

9. Results What is the variability in physicians’ preferences in the same patient? Example: Vt What are physicians’ opinion about other physicians’ advice?

10. Opinion’s about other physicians’ advice ClassificationAverage (range) Good21.2 % (9.9% – 26.0%) Acceptable45.5 % (36.4% – 56.8 %) Unacceptable33.3 % (25.4% – 39.9 %)

11. Opinion’s about other physicians’ advice ClassificationAverage (range) Good21.2 % (9.9% – 26.0%) Acceptable45.5 % (36.4% – 56.8 %) Unacceptable33.3 % (25.4% – 39.9 %) RankBestWorst Average5.07.1 Range2-10

12. Results What is the variability in physicians’ preferences in the same patient? Example: Vt What are physicians’ opinion about other physicians’ advice? What are the physicians’ opinion about INVENT’s advice?

13. Opinion about INVENT’s advice ClassificationAverage (range)INVENT Good21.2 % (9.9% – 26.0%)26.0 % Acceptable45.5 % (36.4% – 56.8 %)41.0 % Unacceptable33.3 % (25.4% – 39.9 %)34.0 %

14. Opinion about INVENT’s advice ClassificationAverage (range)INVENT Good21.2 % (9.9% – 26.0%)26.0 % Acceptable45.5 % (36.4% – 56.8 %)41.0 % Unacceptable33.3 % (25.4% – 39.9 %)34.0 % RankBestWorstINVENT Average5.07.15.3 Range2-10 3-10

15. Conclusions Physiological models may be a beneficial tool for quantifying clinical preferences –Separate variation in preference from variation in patient pathophysiology

16. Conclusions Physiological models may be a beneficial tool for quantifying clinical preferences –Separate variation in preference from variation in patient pathophysiology Large variability found in physicians’ preferences towards appropriate levels of Vt, FiO 2, f, PIP, SaO 2 and pH

17. Conclusions Physiological models may be a beneficial tool for quantifying clinical preferences –Separate variation in preference from variation in patient pathophysiology Large variability found in physicians’ preferences towards appropriate levels of Vt, FiO 2, f, PIP, SaO 2 and pH When a physician’s advice was evaluated by other physicians, a third were found unacceptable

18. Conclusions Physiological models may be a beneficial tool for quantifying clinical preferences –Separate variation in preference from variation in patient pathophysiology Large variability found in physicians’ preferences towards appropriate levels of Vt, FiO 2, f, PIP, SaO 2 and pH When a physician’s advice was evaluated by other physicians, a third were found unacceptable INVENT ranked third best, evaluated similar to physicians –Prospective testing is necessary

19. Thank you.