Intensivist Use of Hand-Carried Ultrasonography to Measure IVC Collapsibility in Estimating Intravascular Volume Status: Correlations with CVP
Received 19 January 2009; received in revised form 23 February 2009; accepted 25 February 2009. published online 01 May 2009.
Background
Volume status assessment is an important aspect of patient management in the surgical intensive care unit (SICU). Echocardiologist-performed measurement of IVC collapsibility index (IVC-CI) provides useful information about filling pressures, but is limited by its portability, cost, and availability. Intensivist-performed bedside ultrasonography (INBU) examinations have the potential to overcome these impediments. We used INBU to evaluate hemodynamic status of SICU patients, focusing on correlations between IVC-CI and CVP.
Study Design
Prospective evaluation of hemodynamic status was conducted on a convenience sample of SICU patients with a brief (3 to 10 minutes) INBU examination. INBU examinations were performed by noncardiologists after 3 hours of didactics in interpreting and acquiring two-dimensional and M-mode images, and ≥25 proctored examinations. IVC-CI measurements were compared with invasive CVP values.
Results
Of 124 enrolled patients, 101 had CVP catheters (55 men, mean age 58.3 years, 44.6% intubated). Of these, 18 patients had uninterpretable INBU examinations, leaving 83 patients with both CVP monitoring devices and INBU IVC evaluations. Patients in three IVC-CI ranges (<0.20, 0.20 to 0.60, and >0.60) demonstrated significant decrease in mean CVP as IVC-CI increased (p = 0.023). Although <5% of patients with IVC-CI <0.20 had CVP <7 mmHg, >40% of this group had a CVP >12 mmHg. Conversely, >60% of patients with IVC-CI >0.6 had CVP <7 mmHg.
Conclusions
Measurements of IVC-CI by INBU can provide a useful guide to noninvasive volume status assessment in SICU patients. IVC-CI appears to correlate best with CVP in the setting of low (<0.20) and high (>0.60) collapsibility ranges. Additional studies are needed to confirm and expand on findings of this study.
aDepartment of Surgery, Division of Traumatology and Surgical Critical Care, University of Pennsylvania School of Medicine, Philadelphia, PA
bDepartment of Medicine, Division of Cardiovascular Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
cDepartment of Emergency Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
Correspondence address: S Peter Stawicki, MD, Department of Surgery, Division of Critical Care, Trauma, and Burn, The Ohio State University Medical Center, Suite 634, 395 West 12th Ave, Columbus, OH 43210
ABSTRACT