1. Predicting fluid response in the critically ill Dr. Andrew Ferguson Consultant in Anaesthesia & Intensive Care Medicine Craigavon Area Hospital

5. Variability of fluid response rates Michard (Chest 2002; 121: 2000-2008)

6. Preload does not guarantee response

7. To be a fluid responder, both ventricles must be on ascending portion of Frank-Starling curve Response depends on contractility and diastolic function as well as load

9. R 2 = 0.2 In spontaneous resp. a fall > 1 mmHg in RAP has positive predictive value of 77-84% and negative predictive value of 81-93% for response

10. R 2 = 0.33

12. ROC curve minimal correlation

14. They don’t work --- what next??

16. BP change relates to SV change

17. Cardio-pulmonary interactions Changes in SV, PP, SBP with positive pressure ventilation

18. Increased pleural pressure RV preload falls LV afterload falls Increased transpulmonary pressure RV afterload increases LV preload increased by alveolar vessel squeeze Decreased RVSV Increased LVSV

19. Inspiratory decrease in RVSV Expiratory decrease in LVSV Expiratory decrease in LV preload Pulmonary transit time

20. Stroke volume variation and LVEDP

25. Systolic Pressure Variation  down is the important one for fluid response

26. Systolic pressure variation

27.  SP as indicator of fluid response

28. Pulse pressure variation

29.  PP as indicator of fluid response

30. Measures of response to volume

31. Predictive values Study No. of patients Measure Threshold Positive pred. val. Negative pred. val. Magder 33  RAP (SPONT) 1 mmHg 84 93 Tavernier 35  Down 5 mmHg 95 93 Magder & Lagonidis 29  RAP (SPONT) 1 mmHg 77 81 Michard 40  PP 13% 94 96 Feissel 19  VPeak 12% 91 100