1. Fluid-Responsiveness:
An ICU Phoenix
Darryl Stewart
Regional ICM Study Day
07/11/2013
Altnagelvin Area Hospital

2. Resuscitation
•
Fluid administration remains the cornerstone of
immediate resuscitation
•
Endless debate regarding timing, volume, duration,
targets & type

3. Goal-directed Therapy

4. Fluid Balance & Mortality
•
Rosenberg AL et al. Review of a large
clinical series: association of cumulative fluid
balance on outcome in acute lung injury: a
retrospective review of the ARDSnet tidal
volume study cohort. JICM 2009; 24:35-46
•
Boyd JH et al. Fluid resuscitation in septic
shock: a positive fluid balance and elevated
central venous pressure increase mortality.
CCM 2011; 39 (2): 259-61
•
Bellomo R et al. An observational study fluid
balance and patient outcomes in the
Randomized Evaluation of Normal vs
Augmented Level of Replacement Therapy
trial. CCM 2012; 40 (6): 1753-60

5. Assessment

6. Often the 1st step…
•
Fluid administration is frequently initial response to
indicators of tissue hypoperfusion
•
However, it is likely that only 50% of haemodynamically
unstable ICU patients are volume responsive
•
Marik PE et al. Dynamic changes in arterial
waveform derived variables and fluid
responsiveness in mechanically ventilated patients.
A systematic review of the literature. CCM 2009; 37:
2642-2647

7. Preload & SV
•
Fluid should only be administered to augment preload
in the belief that this will increase stroke volume &
subsequently cardiac output

8. Haemodynamic changes
with mechanical ventilation

9. Vascular Waveform Analysis
Morgan BC et al. Haemodynamic effects of intermittent positive pressure
ventilation. Anesthesiology 1966; 27: 584-90

10. Systolic Pressure Variation
• Accentuated
in:
•
Hypovolaemia
•
Tamponade
•
Constrictive Pericarditis
•
LV dysfunction
•
Massive PE
•
Bronchospasm
•
Dynamic Hyperinflation
•
Pneumothorax
•
Increased intra-thoracic pressure
•
Increased intra-abdominal pressure

11. Volaemic Assessment
Parameters
Static
Dynamic
CVP
SVV
PAOP
PPV
RVEDV
SPV
LVEDA
IVC collapse
GEDV & ITBV
PLR

12. CVP
•
Kastrup et al, Acta Anaes Scand 2007
•
•
90% German anaesthetists & intensivists used CVP to guide fluid
management (cardiac surgery & CSICU)
McIntyre LA et al, Crit Care 2007
•
90% Canadian intensivists use CVP to guide fluid therapy in septic shock
Assumption
CVP → RAP → RV filling → LV preload → CO

13. •
Systematic review; 213 articles screened, 24 met inclusion criteria =
803pts
Overall 56 +/- 16% (mean +/- SD) of 803pts responded to fluid challenge
with pooled area under ROC curve 0.56. Pooled correlation between
ΔCVP & change in stroke index/cardiac index (7 studies) was 0.11 (95%
CI, 0.01 to 0.21). Baseline CVP (11 studies) was 8.7 +/- 2.3mmHg in
responders, compared to 9.7 +/- 2.2mmHg in non responders (p=0.3)
Therefore the likelihood that CVP can predict responsiveness (at any given
CVP) is no better than a coin toss!
Pts are equally likely to be fluid responsive with low or high CVP!

14. CVP Fraud
•
The assumptions are overly tenuous
Changes in systemic & pulmonary venous capacitance
Changes in intrathoracic pressure
Changes in RV compliance & afterload
Changes in RV systolic function
Changes in LV compliance & filling
Assumption of NSR

16. Chest 2002; 121 (6): 2008-8
•
Systematic review, 12 studies included, looking at predictive factors of
fluid responsiveness in ICU pts
•
Assessed RAP, PAOP, RVEDV, LVEDA, + ΔRAP, Δdown, PPV & Δaortic
blood velocity
•
RAP did not predict fluid responsiveness
•
PAOP investigated in 10 studies; not significantly lower in responder
group in 7 studies, was significantly higher in responder group in 1
study & was significantly lower in responder group in 2 studies.

17. •
RVEDV studied in 6 studies; 4 showed RVEDV was not
significantly lower in responder group; remaining 2 demonstrated
RVEDV was significantly lower in responder group.
•
LVEDA studied in 2 studies only. No significant association
between LVEDA & fluid responsiveness.

18. Problems with preload
indicators
•
CVP & PAOP do not reflect ventricular end-diastolic volumes
•
Ventricular diastolic compliance & filling is non-linear
•
Don’t account for ventricular transmural filling pressures (afterload &
compliance)
•
It is TRANSMURAL pressures not intracavity pressures that are related to
end-diastolic volumes (via compliance)
•
RVEDV is strongly influenced by TR (very common in ICU)
•
IMPORTANT: A patient can be fluid non-responder due to high venous
capacitance, poor ventricular compliance &/or poor ventricular function
•
Little wonder then that intracavity pressures & static chamber dimensions
to not predict fluid responsiveness

19. Dynamic Parameters
•
Numerous studies over last decade shown that
dynamic parameters can better predict fluid
responsiveness than static
•
PPV - from analysis of arterial pressure waveform
•
SVV - from pulse contour analysis
•
Pulse oximeter plethysmography

20. •
40 mechanically ventilated pts in septic shock
•
Demonstrated higher variations in systolic pressure (15%
vs 6%) & pulse pressure (24% vs 7%) during respiration in
pts who were vol responders (increase 15% CI)
•
Derived that cut-off value of 13% for PPV had sensitivity of
94% & specificity 96%.
•
Also, variability in pulse pressure was superior to systolic
pressure variation in discriminating fluid responders.

21. Crit Care Med. 2009 Sep;37(9):2642-7. doi: 10.1097/CCM.0b013e3181a590da.
Dynamic changes in arterial waveform derived variables and fluid responsiveness
in mechanically ventilated patients: a systematic review of the literature.
Marik PE, Cavallazzi R, Vasu T, Hirani A.
•
Meta-analysis of 29 clinical studies, 685 pts to evaluate utility of PPV & SVV in
predicting fluid responsiveness
•
Correlation coefficient for baseline PPV & SVV, and changes in CI or SV in response to
volume expansion were 0.78 & 0.72 respectively.
•
Area under ROC curve for PPV was 0.94, for SVV 0.86
•
Included studies had remarkably consistent threshold PPV/SVV of 12-13% for defining
fluid responsiveness
•
PPV found to be more reliable predictor than SVV (directly measured, no calculated
assumptions)
•
NOTE: Appears to be “grey area” of PPV values (9-13%) were fluid responsiveness
cannot be reliably predicted
•
Cannesson et al. Anesthesiol 2011; 115: 231-241
•
This “grey zone” may affect up to 25% pts under GA

22. Pulse Oximeter
Plethysmography
•
Less invasive alternative to SVV & PPV
•
Uses form of pulse pressure analysis to consider changes in
peak & amplitude of pleth waveform (assesses vol changes)
•
Numerous studies demonstrating significant correlation between
changes in pulse oximeter waveform & PPV & hence may predict
fluid responders
•
“Pleth Variability Index” (Masimo, Irvine)
•
Automatic measure of dynamic change in perfusion index (pulsatile:nonpulsatile blood flow)
during ventilation.
•
Pleth variability index >14% is predictive that pt will be fluid responder with sensitivity 81%

23. Dynamic Limitations
•
Arrhythmias & spontaneous respiration may influence change in PPV /
SVV response to volume loading
•
PPV / SVV varies with tidal volume, PEEP, chest wall compliance etc
•
De Backer et al, ICM 2005, demonstrated tidal volume must be > 8
ml/kg to ensure accuracy
•
Lansdorp et al, BJA 2012, demonstrated predictive value of SPV,
SVV & PPV were optimal when Vt >7ml/kg & patient in SR
•
Requires optimum arterial trace
•
PVI influenced by acute vasomotor changes

24. Oesophageal Doppler

25. Oesophageal Doppler
•
Respiratory changes in aortic peak velocity may
used to estimate fluid responsiveness (Monnet X et
al, ICM 2005)
•
Feissel et al, Chest 2001, demonstrated that a
change in aortic peak velocity with respiration
>12% allowed discrimination between fluid
responders & non-responders with sensitivity of
100% & specificity 89%.

26. IVC Collapse
•
Intrathoracic pressure changes affect VR & therefore
diameter IVC
•
Absolute diameter or Δdiameter have both been used
to assess col status
•
Sefidbakht et al, Emer Radiol 2007, developed vena
cava collapsibility index (= (end-expiratory diameter end-inspiratory diameter) / end-expiratory diameter).
•
Those who responded had greater collapsibility at baseline (25% vs 6%)

27. Intensive Care Medicine
September 2004, Volume 30, Issue 9, pp 1734-1739
Superior vena caval collapsibility as a gauge of volume status in
ventilated septic patients
Antoine Vieillard-Baron, Karim Chergui, Anne Rabiller, Olivier Peyrouset, Bernard Page, Alain Beauchet, François Jardin
•
Studied 66 pts in medical ICU with “ALI”
•
Used TOE Doppler to measure SVC collapsibility at
baseline and following 10ml/kg fluid (HES).
•
Threshold SVC collapsibility of 36% allowed
discrimination between responders and nonresponders (defined by increase CI of at least 11%)
with a sensitivity of 90% & specificity of 100%

28. Passive Leg Raise
•
All previous techniques required sedated, ventilated pts
•
PLR can be used reliably in awake pts with cardiac dysrhythmias
•
Numerous studies demonstrating ability of PLR to predict fluid
responsiveness
•
Cavallaro et al, ICM 2010, meta-analysis determined AUC for PLR in
determining fluid responsiveness was 0.95
•
Should use CO monitor - FloTrac-Vigleo system can be used to
measure SVV with PLR where a 10% or greater increase in CO
predicts fluid responsiveness (Biais M et al, CC 2009)

29. Summary