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Three Part Question

In [critically ill adult patients], does [ultrasonography of the inferior vena cava] predict [volume responsiveness]?

Clinical Scenario

A 75 years old man presents at the ED with a pneumonia and severe sepsis. The patient is also known for cardiac failure. After being intubated and having received few liters of fluids, the patient does not seem to get better. The physician wonders if the ultrasonography of the inferior vena cava would help him to know if the patient is fluid-responsive or not.

Search Strategy

No best bet on this topic was found.
Ovid MEDLINE(R) 1950 to November week 4 2009 : 171
EMBASE 1950 to November week 4 2009 via Elsevier: 277
Cochrane library to November week 4 : 0

Medline search :
(("Vena Cava, Inferior" AND and ultrasonography) OR ("Inferior Vena Cava" AND and ultrasonography) OR ("Inferior Vena Cava" AND and ultrasound) OR ("Vena Cava, Inferior" AND and ultrasound)) AND ((Fluid therapy/methods*) OR (hemodynamics*) OR (shock/therapy*) OR (shock fluid resuscitation) OR (fluid responsiveness) OR (fluid resuscitation) OR (volume resuscitation) OR (volume responsiveness))

Search Outcome

Inclusion criteria:
- Population: Critically ill adult patients
- Intervention: Ultrasonography of the inferior vena cava before volume expansion
- Studies: Meta-analysis, systematic reviews, RCT, observational studies
- Outcomes: Prediction of increase in cardiac index after volume expansion

Exlcusion criteria: Pediatrics, animal subjects, prehospital setting

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Barbier et al. 2004 France	23 adult patients with acute circulatory failure (systolic arterial pressure below 90mmHg and/or perfusion of vasopressor amines) related to sepsis and mechanically ventilated (tidal volume 8,5+/-1,5ml/kg, PEEP 4+/-2) because of an acute lung injury.	Prospective observational study	Fluid responsiveness define as 15% or more increase in cardiac index after a 30 min 7ml/kg volume expansion using plasma expander (4% modified fluid gelatin)	- Of all parameter changes (heart rate, systolic arterial pressure, cardiac index, central venous pressure, dose of vasopressor and distensibility index (dIVC), only dIVC differed significantly between the two groups - Using a threshold distensibility index (dIVC) of the IVC of 18%, responders and non-responders were discriminated with 90% sensitivity and 90% specificity - A strong relation (r=0,9) was observed between dIVC at baseline and the cardiac index increase following blood volume expansion - N.B.: dIVC = IVC maximum diameter on inspiration (Dmax) – IVC minimum diameter on expiration (Dmin) /Dmin)	- Abdominal pressure was not measure for all patients. - First observer was not blind to fluid administration. - Intra- and inter-observer variabilities in the measurement of IVC diameter were 6,3+/-8 and 8.7+/-9%, respectively. - Training of the observer was not describe. - Cardiac index was calculated from the right ventricular outflow tract. - Fluid used was not normal saline or ringer lactate. - Three patients were excluded because of their poor response to echocardiography. - Other treatments were not standardized. - dIVC was not compared to delta of pulse pressure or superior vena cava ultrasonography as a marker of fluid responsiveness. - Tricuspid regurgitation and vena cava backward flow may be observed in mechanically ventilated patients which can affecte the size of the IVC and then RCIVCD. The impact of this regurgitation can be avoided if RCIVCD measurement is made at end-diastole period, but this method was not used.
Feissel et al. 2004 France	39 mechanically ventilated (tidal volume 8-10 ml/kg) patients with septic shock	Prospective observational study	Fluid responsiveness define as 15% or more increase in cardiac index after a 20 min 8ml/kg volume expansion using plasma expander (6% hydroxyethylstarch modified fluid gelatin)	- ΔIVC is more elevated (25 +/- 15%) in fluid responsive patient compare to non fluid responsive patients (6 +/- 4%) - A linear correlation exists between the ΔIVC and the pourcentage of cardiac index augmentation (r=0,82) - IVC max and IVC min showed less correlation (r = 0,44 for IVC max and r = 0,58 for IVC min) - ΔIVC of 12% or more predicts fluid responsiveness with a PPV of 93% and NPV of 92% - N.B.: ΔIVC = IVC max-IVCmin/IVCmax+IVCmin/2	- Abdominal pressure was not measure. - Blinding is not describe. - Intra- and inter-observer variabilities in the measurement of IVC diameter is unknown. - Training of the observer was not describe. - Fluid used was not normal saline or ringer lactate. - ΔIVC was not compared to delta of pulse pressure or superior vena cava ultrasonography as a marker of fluid responsiveness.

Comment(s)

Population To use ultrasonography of the inferior vena cava, the patient must be ventilated in the volum-controlled mode and strictly adapted too the ventilator. Pratically, patients should be deeply sedated or paralyzed to preclude any voluntary ventilatory efforts. The patient should be in sinus rythm. Respiratory variation of the vena cava diameter should be cautiously interpreted when small tidal volumes and high level of PEEP are used. Also, clinical situations associated with increased intra-abdominal pressure or elevated right atrial pressure may potentially invalidate the use of respiratory variation in the IVC diameter to predict fluid responsiveness. Intervention Barbier and Feissel used a sub-xyphoidal long axis view method and measured the IVC in M-mode. The training required to be able to use ultrasonography of the inferior vena cava is unknown. Comparaison Superior vena cava with trans-oesophageal ultrasonography and delta of pulse pressure are other options described in the litterature. Ultrasonography of the inferior vena cava was not compared to those two other measures. Outcomes Those results from prospective observational studies were done in small very specific cohorts. Other studies are required to evaluate the external validity.

Editor Comment

CF

Clinical Bottom Line

Ultrasonography of the inferior vena cava (dIVC or ΔIVC) predicts volume responsiveness in intubated critically ill adult patients strictly adapted too ventilator.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.

References

1. Barbier C, Loubières Y, Schmit C, Hayon J, Ricôme JL, Jardin F, Veillard-Baron A Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients Intensive Care Med. 2004 Sep;30(9):1740-1746
2. Feissel M, Michard F, Faller JP, Teboul JL The repiratory variation in inferior vena cava diameter as a guide to fluid therapy Intensive Care Med. 2004 Sep ;30(9) :1699-1701