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Evaluation of tissue perfusion parameters and intravascular volume, emphasizing the inferior vena cava diameter and collapsibility


Echocardiography in critically ill patients enables diagnosis of a large number of cardiac conditions, including life-threatening ones. Intensivists can use it as a powerful diagnostic tool.


A comparison of intravascular volume and tissue perfusion parameters in critically ill patients to enhance beneficial conduct in treatment and outcome using the inferior vena cava diameter as guidance.

Materials and methods

Patients were enrolled from November until December 2006 in the ICU of the Emergency Department at HMSA. Inclusion criteria: (a) hemodynamic instability or dependency on vasoactive drugs, at the first 6 hours; (b) age >18 years; (c) deep vein access in superior vena cava. Evaluation of the intravascular volume and tissue perfusion parameters followed after admission, with normal values being defined as cardiac rate (CR: 80–100 bpm); mean blood pressure (MBP: >90 mmHg); central venous pressure (CVP: 8–12 mmHg); serum lactate (Lac: < 1 mmol/l); arterial oxygen saturation (SaO2: >90%); central venous oxygen saturation (ScvO2: >75%); ΔPCO2 (<4 mmHg indicates a cardiac index >2.5 l/min/m2); inferior vena cava diameter (IVC: >15 mm) and its variation with inspiration (ΔIVC: <50%).


A total of 32 patients were investigated – of which five presented with the following apparent divergences:

  1. 1.

    CR: 98 bpm; MBP: 80 mmHg, in use of norepinephrine (NE); CVP: 12 mmHg; Lac: 1.6 mmol/l; SaO2: 98.1%; SvcO2: 54.9%; ΔPCO2: 5 mmHg; IVC: 24 mm; ΔIVC: 10%. Procedure: patient with severe left ventricular dysfunction. Increased IVC demanded initiation of inotropic drugs.

  2. 2.

    CR: 128 bpm; MBP: 119 mmHg, in use of NE; CVP: 18.4 mmHg; Lac: 9.6 mmol/l; SaO2: 96.5%; SvcO2: 83.8%; ΔPCO2: 1.7 mmHg; IVC: 3 mm; ΔIVC: 66%. Procedure: septic patient, hyperdynamic. Decreased IVC resulted in volume replacement.

  3. 3.

    CR: 86 bpm; MBP: 75 mmHg; CVP: 6.5 mmHg; Lac: 1.1 mmol/l; SaO2: 87%; SvcO2: 81.2%; ΔPCO2: 6.2 mmHg; IVC: 7 mm; ΔIVC: 70%. Procedure: trauma victim with ARDS, in mechanical ventilation (PEEP: 12 cmH2O). Decreased IVC resulted in volume infusion.

  4. 4.

    CR: 106 bpm; MBP: 60 mmHg; CVP: 5.5 mmHg; Lac: 1.6 mmol/l; SaO2: 95.9%; SvcO2: 74.3%; ΔPCO2: 3.4 mmHg; IVC: 12 mm; ΔIVC: 60%. Procedure: patient with subarachnoid hemorrhage. Normal IVC diameter and collapsibility helped to maintain MBP > 100 mmHg and prevent vasospasm.

  5. 5.

    CR: 128 bpm; MBP: 90 mmHg; CVP: 18.5 mmHg; Lac: 1.4 mmol/l; SaO2: 80%; SvcO2: 71.2%; ΔPCO2: 3.2 mmHg; IVC: 25 mm; ΔIVC: 5%. Procedure: hypervolemic patient with ARDS, in mechanical ventilation (APRV-Bilevel). Increased IVC resulted in volume restriction and use of diuretics to improve P/F.


Cases reported in this study demonstrate how the IVC helped monitor hemodynamics in critically ill patients and led to further decisions in treatment. Other studies also recommend the incorporation of this technology as a routine in ICUs due to its noninvasivity, feasibility, accessibility and lower risks.


  1. 1.

    Feissel M, Michard F, Faller JP: The respiratory variation in inferior vena cava diameter as a guide to fluid therapy. Intensive Care Med. 2004, 30: 1834-1837. 10.1007/s00134-004-2233-5.

  2. 2.

    Jardin F, Vieillard-Baron A: Ultrasound examination of the venae cavae. Intensive Care Med. 2006, 134: 203-206. 10.1007/s00134-005-0013-5.

  3. 3.

    Price S, Nicol E, Gibson DG: Echocardiography in the critically ill: current and potential roles. Intensive Care Med. 2006, 32: 48-59. 10.1007/s00134-005-2834-7.

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  • Mechanical Ventilation
  • Oxygen Saturation
  • Cardiac Index
  • Central Venous Pressure
  • Left Ventricular Dysfunction