ISPUB.com / IJEICM/10/1/4834
  • Author/Editor Login
  • Registration
  • Facebook
  • Google Plus

ISPUB.com

Internet
Scientific
Publications

  • Home
  • Journals
  • Latest Articles
  • Disclaimers
  • Article Submissions
  • Contact
  • Help
  • The Internet Journal of Emergency and Intensive Care Medicine
  • Volume 10
  • Number 1

Original Article

Measurement of Blood Volume at Bedside: New Era in Critical Care Medicine

B Vahid

Keywords

blood volume, blood volume analyzer, i tracer, plasma volume

Citation

B Vahid. Measurement of Blood Volume at Bedside: New Era in Critical Care Medicine. The Internet Journal of Emergency and Intensive Care Medicine. 2006 Volume 10 Number 1.

Abstract

Accurate assessment of volume status of the critically care ill patients in the intensive care unit is a challenging task facing intensivits each day. Since direct measurement of blood volume at bedside has not been readily accessible and practical in the past, clinicians have used clinical surrogates instead. It has been shown that the accuracy of these clinical data in estimating of patients' volume status is less than 50%. To overcome these limitations several methods have been developed to measure blood volume by using tracer dilution technique, but there are many problems with these techniques and most of them are complicated, time consuming, unreliable, and not readily available for clinical use. A semi-automated instrument approved by US food and Drug Administration is currently available that can measure blood volume in less than 90 min with a 98% accuracy. In two small studies, this technology has been shown to influence treatment decisions in 20% to 35% of patients. More studies are necessary to further define the role of bedside volume analysis in critical care medicine.

 

Accurate assessment of volume status of the critically care ill patients in the intensive care unit is a challenging task facing intensivits each day. Failure to correct the volume deficit in patients with shock is known to significantly increase the morbidity and mortality in these patients1. On the other hand, fluid overload may cause worsening pulmonary edema, worsening hypoxemia, and deleterious effect in patients with acute respiratory distress syndrome2. Assessment of volume status becomes even more complicated when caring for patients with congestive heart failure, pulmonary arterial hypertension, renal failure, and cirrhosis.

Since direct measurement of blood volume at bedside has not been readily accessible and practical in the past, clinicians have used clinical surrogates instead. The clinical data that have been utilized to estimate the patients' blood volume are as follows: 1. History, 2. Physical examination (skin mottling, pulmonary crackles, and peripheral edema) 3.Urine output, 3. Sodium concentration, 4. Measurement of ongoing fluid loss in ICU like chest tube or abdominal drain output, 5. Fluid balance in the last 24 hours, 6. Presence of pulmonary congestion on chest x-ray, 7. Spot urinary sodium concentration3. It has been shown that the accuracy of these clinical data in estimating of patients' volume status is less than 50%3, 4 , 5. Monitoring of routine hemodynamic variables also has little value to differentiate hypovolemic and non-hypovolemic patients6, 7. Urine output and spot urinary sodium concentration may vary due to conditions commonly seen in critically ill patients like hyperglycemia, renal failure, diuretic agents, post-obstructive diuresis, and nephrogenic diabetes insipidius. Since there are too many confiding factors, urinary output and spot urinary sodium concentration are not useful in estimation of volume status in critically ill patients3, 8. The hemoglobin concentration also has no value in determining the blood volume for two major limitations, 1. In rapid severe bleeding, drop in hemoglobin values is a late finding, and 2. Hemoglobin concentration becomes uninterruptible after infusion of packed red cells or large volume of fluids.

Monitoring of central venous pressure (CVP) and pulmonary arterial occlusion pressure (PAOP) has been used commonly in critically ill patients to assess the patients' volume status. Because CVP varies considerably in critically ill patients, due to heart-lung interaction especially in mechanically ventilated patients, CVP has no significant clinical value in these patients. PAOP also has been shown to fail to predict ventricular filling pressure, blood volume, and response to volume infusion3, 9, 10. Measurement of CVP and PAOP is invasive and requires central venous catheter access that carries risks of pneumothorax, infection, and bleeding.

Because of above-mentioned limitations, several methods have been developed to measure blood volume by using tracer dilution technique. The tracer should be inert, safe, and remains within intravascular compartment. Tracers for blood volume measurement that have been used include 1.I125Radio-labeled albumin, 2. Synthetic colloids (Hetastarch, dextran-70), 3.Small molecules that bind to plasma proteins (Evan's blue dye, indo-cyanine green), 4. Red cell labeling (chromium-51, carbon monoxide). There are many problems with these techniques and most of them are complicated, time consuming, unreliable, and not readily available for clinical use11.

A semi-automated instrument (BVA-100, Dexor Corporation) approved by US food and Drug Administration (FDA) is currently available that can measure blood volume in less than 90 min with a 98% accuracy. The blood volume is measured after intravenous injection of 10 to 25 µ Ci of iodine-131-labeled albumin12. Information provided by blood volume analyzer is shown in table 1.

Figure 1
Table 1: Information provided by blood volume analyzer

Two studies have evaluated the value of bedside blood volume analyzer. Yamauchi et al showed that although there was a statically significant correlation between PAOP and blood volume, blood volume information resulted in different treatment in 21% of the time13. In another retrospective study of 40 surgical patients, Biuk-Aghai et al demonstrated that treatment change occurred in 36% cases with addition of blood volume information. The treatment changes included less fluid infusion, less diuretic use, and packed blood transfusion14. Although these results are interesting, further studies are necessary to document the impact of bedside blood volume analyzer on major outcomes like mortality, ICU stay, ventilator free days, and hospital stay. Bedside blood volume analyzer provides the researchers and clinicians with and effective and practical tool that enable them to answer important questions in critical care medicine by performing new studies that were not easily possible in the past.

References

1. Shoemaker WC, Montgomery ES, Kaplan E, Elwyn DH. Physiologic patterns in surviving and nonsurviving shock patients. Arch Surg 1973; 106:630-636
2. Mitchell JP, Schuller D, Calandrino FS, Schuster DP. Improved outcome based on fluid management in critically ill patients requiring pulmonary artery catheterization. Am Rev Resp Dis 1992;145:990-998
3. Stéphan F, Flahault A, Dieudonné N, Hollande J, Paillard F, Bonnet F. Clinical evaluation of circulating blood volume in critically ill patients-contributing of a clinical scoring system. Br J Anaesth 2001;86:754-762
4. Cook DJ. Clinical assessment of central venous pressure in the critically ill. Am J Med Sci 1990;299:175-178
5. McGee S, Abernethy WB, Simel DL. Is this patient hypovolemic? JAMA 1999;281:1022-1029
6. Shippy CR, Appel PL, Shoemaker WC. Reliability of clinical monitoring to assess blood volume in critically ill patients. Crit Care Med 1984; 12:107-112
7. Lazrove S, Waxman K, Shippy C, Shoemaker WC. Hemodynamic, blood volume, and oxygen transport responses to albumin and hydroxyethyl starch infusions in critically ill postoperative patients. Crit Care Med 1980;8:302-306
8. Chung H-M, Kluge R, Schrier RW, Anderson RJ. Clinical assessment of extracellular fluid volume in hyponatremia. Am J Med 1987;83:905-908
9. Kumar A, Anel R, Bunnell E, Habet K, Zanotti S, et al. Pulmonary artery occlusion pressure and central venous pressure fail to predict ventricular filling pressure, cardiac performance, or the response to volume infusion in normal subjects. Crit Care Med 2004;32:691-699
10. Alrawi SJ, Miranda LS, Cunnigham Jr JN, Acinapura AJ, Raju R. Correlation of blood volume values and pulmonary artery catheter measurements. Saudi Med J 2002;23:1367-1372
11. Margarson MP, Soni NC. Plasma volume measurement in septic patients using an albumin dilution technique: comparison with the standard radio-labeled albumin method. Intensive Care Med 2005;31;289-295
12. Androne AS, Hryniewicz K, Hdaihed A, Mancini D, Lamanca J, Katz S. Relation of Unrecognized Hypervolemia in Chronic Heart Failure to Clinical Status, Hemodynamics, and Patient Outcomes. Am J Cardiol 2004;93:1254-1259
13. Yamauchi H, Biuk-Aghai EN, Yu M, Ho H-C, Chapital A, Takanishi D. Correlation Between Blood Volume an Pulmonary Artery Catheter Measurement. Crit Care Med 2006;33:A47
14. Buik-Aghai EN, Yamauchi H, Yu M, Ho H-C, Chapital A, Takanishi D. Blood Volume Measurements: Impact on Fluid Management. Crit Care Med 2006;33:A37

Author Information

Bobbak Vahid, M.D.
Department of Pulmonary and Critical Care Medicine, Thomas Jefferson University Hospital

Your free access to ISPUB is funded by the following advertisements:

Advertisement

 

BACK TO TOP
  • Facebook
  • Google Plus

© 2013 Internet Scientific Publications, LLC. All rights reserved.    UBM Medica Network Privacy Policy

Close

Enter the site

Login

Password

Remember me

Forgot password?

Login

SIGN IN AS A USER

Use your account on the social network Facebook, to create a profile on BusinessPress