Classic Textbook on Critical Care, the ICU book by Paul Marino, M.D., PhD., Recommends Direct Measurement of Blood Volume in Evaluating Critically Ill Patients

NEW YORK, NY--(Marketwired - Jan 7, 2014) - Daxor Corporation (NYSE MKT: DXR)

The most widely read textbook in critical care medicine is the ICU book (intensive care unit) by Paul Marino, M.D. The fourth edition of this book has just been published by Lippincott Williams & Wilkins, and has important information about blood volume measurement. Dr. Marino, who is on the staff of Cornell Medical School, is an internationally recognized authority on critical care medicine. 

The previous third edition was published in 2007. The fourth edition has important new information about the use of blood volume measurement. In a chapter on hypovolemia (low blood volume) Dr. Marino writes "Blood volume measurements have traditionally required too much time to perform to be clinically useful in an ICU setting, but this has changed with the introduction of a semi-automated blood volume analyzer (Daxor Corporation, New York, NY) that provides blood volume measurements in less than an hour. Blinded measurements of blood, red cell, and plasma volumes were performed in patients with circulatory shock who were managed with pulmonary artery catheters, and the results show that blood and plasma volumes were considerably higher than normal. When blood volume measurements were made available for patient care, 53% of the measurements led to a change in fluid management, and this was associated with a significant decrease in mortality rate (from 24% to 8%). These results will require corroboration, but they highlight the limitations of the clinical assessment of blood volume, and the potential for improved outcomes when blood volume measurements are utilized for fluid management." Dr. Marino's book cited a study by Dr. Mihae Yu and included a graph of her research which was published in Shock (A Prospective Randomized Trial Using Blood Volume Analysis in Addition to Pulmonary Artery Catheter, Compared with Pulmonary Artery Catheter Alone, to Guide Shock Resuscitation in Critically Ill Surgical Patients; Shock, Vo. 35, No. 3, pp 220-228, 2011). This landmark study by Dr. Yu studied 100 critically ill patients in the ICU. 50 of them were treated on the basis of a blood volume measurement plus PAC, and 50 were treated on the basis of PAC without knowledge of the blood volume measurement. The patients who were treated on the basis of a blood volume measurement had an 8% death rate vs. a 24% death rate in the patients who were treated without knowledge of the blood volume measurement. 

The most common laboratory tests to evaluate a patient's blood volume are the hematocrit and hemoglobin tests. These tests only measure the concentration of red blood cells, not the volume of the patient's blood. Dr. Marino's book contains the following statement "The use of the hematocrit (and hemoglobin concentration) to evaluate the presence and severity of acute blood loss is both common and inappropriate. Changes in hematocrit show a poor correlation with blood volume deficits and erythrocyte deficits in acute hemorrhage. Acute blood loss involves the loss of whole blood, which results in proportional decreases in the volume of plasma and erythrocytes. As a result, acute blood loss results in a decrease in blood volume but not a decrease in hematocrit. (There is a small dilutional effect from transcapillary refill in acute blood loss, but this is usually not enough to cause a significant decrease in hematocrit.) In the absence of volume resuscitation, the hematocrit will eventually decrease because hypovolemia activates the rennin-angiotensin-aldosterone system, and the renal retention of sodium and water that follows will have a dilutional effect on the hematocrit. This process begins 8 to 12 hours after acute blood loss, and can take a few days to become fully established." That statement is based on original research by Drs. S. Oohashi and H. Endoh, who examined physicians' assessments of patients' blood volumes with actual blood volume measurements and found them to be extremely disparate. Previously, studies from Columbia Presbyterian Medical Center also demonstrated that physicians treating heart failure patients were only correct 51% of the time using the usual clinical parameters and laboratory tests in evaluating the blood volume status of a patient.

Dr. Marino's chapter focused particularly on the detection of hypovolemia (low blood volume). He cited studies which used invasive procedures such as pulmonary artery catheterization (PAC) and central venous pressure to assess a patient's blood volume. Previous studies have demonstrated, in situations where blood volume measurements were actually made, that such assessments are frequently wrong. 

Dr. Feldschuh, the president of Daxor, a board certified cardiologist, noted that it is truly tragic that the overwhelming majority of patients treated in intensive care units are not treated based on actual blood volume measurements. Instead, they are treated on the basis of inaccurate tests such as hematocrits and hemoglobins, and invasive procedures such as pulmonary artery catheterization, which multiple studies have shown to be inaccurate for evaluating a patient's blood volume.

Dr. Feldschuh stated that it is unfortunate that thousands of patients die every year because they are not treated correctly due to inaccurate assessments of blood volume. These tests only measure the concentration of red blood cells in a patient, they do not measure a patient's total blood volume. The BVA-100 can measure blood volume to an accuracy of 98%.

Dr. Marino closed this particular chapter with the following comments: "The clinical evaluation of intravascular volume, including the use of central venous pressure (CVP) measurements, is so flawed it has been called a 'comedy of errors'" and "Direct measurements of blood volume are clinically feasible, but are underutilized." 

The past week extensive publicity was given to the case of a 13 year old girl in California who had a tonsillectomy and was said to have bled extensively. Unfortunately her blood loss was not properly replaced and she was pronounced brain dead. This is the type of case that occurs by the thousands every year. In addition to patients who die from inadequate treatment, thousands more suffer heart attacks and strokes. Many patients with lack of brain oxygen ultimately develop dementia. Lack of oxygen to the brain is well known to destroy and irreversibly damage brain cells. The knowledge of how to perform accurate blood volume measurement has been known for more than 70 years. An automated blood volume measurement instrument has been available for more than 10 years. The excuse for not performing blood volume measurement has always been that the test is too difficult to perform accurately and takes 4 to 8 hours. The BVA-100 has automated most of the procedure and enables the blood volume measurement to be done in under an hour. Inability to obtain rapid blood volume measurements should no longer be an excuse for treating critically ill patients with blood volume derangements on the basis of tests which are known to be inaccurate and may result in irreversible damage and even death to patients. 

Dr. Feldschuh will be attending the annual meeting of Critical Care Medicine in San Francisco January 8 - 13, 2014. This is the main annual meeting of physicians specializing in intensive care unit medicine.