- Email: [email protected]
Estimation of blood volume in burns patients using radioisotope chromium-51: A pilot study
burns 33 (2007) 1072–1073
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/burns
Letter to the Editor
Estimation of blood volume in burns patients using radioisotope chromium-51: A pilot study Sir, One of the main factors that can alter homeostasis is blood volume, the amount of blood that fills and distends the cardiovascular system. Measuring blood volume has diagnostic application in extensive burns patients where hemoconcentration is a frequent problem [1] that is usually treated by administering intravenous fluids, as calculated by various formulae derived from clinical experiences and facts by burns surgeons. With recent developments in the field of medicine, we feel the need for more accurate methods for resuscitation in these situations, based on more accurate evidences, using improved technical devices and experiments. Dye dilution technique using T-1824/Evan’s blue [2] that was used extensively, was abandoned in view of reports of sensitivity reactions and unacceptable levels of patient discoloration. The concern of using radioisotopic labeling involving either albumin or RBC [3] is that it cannot be repeatedly done on the same patient due to the prolonged stay in the body of the radioisotope in the labeled form. To overcome these shortcomings, we undertook this pilot study of intravenous injection of chromium-51 (in the form of sodium chromate) to estimate the blood volume in clinical setting. This almost instant and accurate blood volume estimation method can be used to monitor the hemodynamic status on frequent basis. A total of 11 patients were studied out of which five patients were lost in standardization of the procedure. Before starting the study, an informed consent was taken and the procedure was explained to the patient and the relatives. The Human Ethical Committee, Kasturba Medical College, Manipal University, Manipal approved the study. Since the procedure was new, we required five patients for standardization of the procedure, which included, training of the personnel in handling the radioisotope Cr-51, method of collecting sample and method of counting radioactivity in the sample. Two IV cannulae were inserted, one on each limb, other than used for resuscitation of the patient. Cr-51 (80–100 mCi) in 1 mL volume was injected into one of the cannulae and blood samples were collected from the other at 1, 2 and 10 min. Dilution of 1:100 was used for counting
standard samples. During standardization, it was observed that a maximum count in blood was achieved at 1 min with steady decline in subsequent samples, which was attributed to loss of Cr-51 in excretion and fixation to other organs. Samples were counted in well-counter as it was easy to use and highly sensitive for detection of the radioactivity in the form of gamma rays emitted from Cr-51. The counter was standardized and the radioactivity of all the samples including the standard was counted for 10 min. After the standardization of the procedure, the data from six patients, who were hemodynamically stable and from one control, were analyzed and were tabulated and reported in the observation (Tables 1 and 2). Analysis of the data was done based on the standard formula used for dilution technique of blood volume estimation using radiotracer:
blood volume ðmlÞ V2 ¼
C1 V1 100 C2
where C1 is the standard counts of added radioisotope tracer, C2 the concentration of radioisotope in blood withdrawn, V1 the volume of radiotracer injected, and V2 is the blood volume. Being a new procedure along with involvement of radiotracer, we found it difficult to convince the patient about the safety of the procedure and many patients opted not to participate in the study. In this study we analyzed the data of only six patients and one normal person who were hemodynamically stable. Further data concerning reproducibility, day to day variations and limits of detection of changes in circulating blood volume are still required and further studies have to be undertaken to standardize the procedure. In conclusion, this study is simple, quick and can be easily carried out in ward settings. The results by the study and blood volume estimated according to weight are comparable. The total time for single estimate of circulating blood volume is only in the order of 1 min after injecting the radiotracer and the accuracy of the method is sufficient for clinical purposes. Hence this study of estimating circulating blood
1073
burns 33 (2007) 1072–1073
Table 1 – Blood volume estimation in subjects under study using radioisotopes Cr-51 Serial no.
Patient no.
C1 standard counts
Cr counts
V1 standard (ml)
1 min
2 min
10 min
V2 ðLÞ ¼ C1CV1 100 100 2
Study group (n = 7) 1 2 3 4 5 6
1 2 3 4 5 6
42461 30804 31004 25470 32280 42260
839 716 719 684 861 928
813 651 654 652 788 864
735 631 615 524 795 872
1 1 1 1 1 1
5.06 4.30 4.31 3.72 3.79 4.55
Control 1
1
42324
780
642
624
1
5.4
Table 2 – Blood volume estimation in subjects under study by weight method Serial no.
Patient no.
Age (year)
Sex
Weight (kg)
Hb (g%)
PCV (%)
Blood volume (L) By weight [3]
Study group 1 2 3 4 5 6 Control 1
By present study
1. 2. 3. 4. 5. 6.
36 38 38 42 22 36
M M M M F F
61 58 72 62 46 51
12.2 15.8 14.2 14.3 13.6 12.1
36.7 45.2 48.6 46.4 36.8 36.7
4.27 4.06 5.04 4.34 3.22 3.57
5.06 4.30 4.31 3.72 3.79 4.55
1.
45
M
75
14.6
48.7
5.25
5.40
volume is a potentially useful clinical tool for monitoring critical patients.
references
[1] Webb AR. Fluid management in intensive care—avoiding hypovolemia. Br J Intens Care 1997;7:59–64. [2] Frienkel N, Screiner GE, Athens JW. Simultaneous distribution of T-1824 and 131iodine-labelled human serum albumin in man. Lab Clin Invest 1953;32: 138–48. [3] ICSH. Interpretation of measured red cell mass and plasma volume in adults: expert panel on radionuclides of the international council for standardization in hematology. Br J Haematol 1995;89:748–56.
Pramod Kumar* Department of Burns and Plastic Surgery, Kasturba Medical College, Manipal 576104, Karnataka, India
Rajesh Kumar Nandini Pandit Department of Nuclear Medicine, Kasturba Medical College, Manipal 576104, Karnataka, India Amit Aggrawal Kasturba Medical College, Manipal 576104, Karnataka, India Prathap M. Baby Department of Physiology, Melaka-Manipal Medical College (Manipal Campus), International Centre for Health Sciences, India *Corresponding author. Tel.: +91 8202571201x22135 E-mail address: [email protected] (P. Kumar) 0305-4179/$32.00 # 2007 Elsevier Ltd and ISBI. All rights reserved. doi:10.1016/j.burns.2007.03.006
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/burns
Letter to the Editor
Estimation of blood volume in burns patients using radioisotope chromium-51: A pilot study Sir, One of the main factors that can alter homeostasis is blood volume, the amount of blood that fills and distends the cardiovascular system. Measuring blood volume has diagnostic application in extensive burns patients where hemoconcentration is a frequent problem [1] that is usually treated by administering intravenous fluids, as calculated by various formulae derived from clinical experiences and facts by burns surgeons. With recent developments in the field of medicine, we feel the need for more accurate methods for resuscitation in these situations, based on more accurate evidences, using improved technical devices and experiments. Dye dilution technique using T-1824/Evan’s blue [2] that was used extensively, was abandoned in view of reports of sensitivity reactions and unacceptable levels of patient discoloration. The concern of using radioisotopic labeling involving either albumin or RBC [3] is that it cannot be repeatedly done on the same patient due to the prolonged stay in the body of the radioisotope in the labeled form. To overcome these shortcomings, we undertook this pilot study of intravenous injection of chromium-51 (in the form of sodium chromate) to estimate the blood volume in clinical setting. This almost instant and accurate blood volume estimation method can be used to monitor the hemodynamic status on frequent basis. A total of 11 patients were studied out of which five patients were lost in standardization of the procedure. Before starting the study, an informed consent was taken and the procedure was explained to the patient and the relatives. The Human Ethical Committee, Kasturba Medical College, Manipal University, Manipal approved the study. Since the procedure was new, we required five patients for standardization of the procedure, which included, training of the personnel in handling the radioisotope Cr-51, method of collecting sample and method of counting radioactivity in the sample. Two IV cannulae were inserted, one on each limb, other than used for resuscitation of the patient. Cr-51 (80–100 mCi) in 1 mL volume was injected into one of the cannulae and blood samples were collected from the other at 1, 2 and 10 min. Dilution of 1:100 was used for counting
standard samples. During standardization, it was observed that a maximum count in blood was achieved at 1 min with steady decline in subsequent samples, which was attributed to loss of Cr-51 in excretion and fixation to other organs. Samples were counted in well-counter as it was easy to use and highly sensitive for detection of the radioactivity in the form of gamma rays emitted from Cr-51. The counter was standardized and the radioactivity of all the samples including the standard was counted for 10 min. After the standardization of the procedure, the data from six patients, who were hemodynamically stable and from one control, were analyzed and were tabulated and reported in the observation (Tables 1 and 2). Analysis of the data was done based on the standard formula used for dilution technique of blood volume estimation using radiotracer:
blood volume ðmlÞ V2 ¼
C1 V1 100 C2
where C1 is the standard counts of added radioisotope tracer, C2 the concentration of radioisotope in blood withdrawn, V1 the volume of radiotracer injected, and V2 is the blood volume. Being a new procedure along with involvement of radiotracer, we found it difficult to convince the patient about the safety of the procedure and many patients opted not to participate in the study. In this study we analyzed the data of only six patients and one normal person who were hemodynamically stable. Further data concerning reproducibility, day to day variations and limits of detection of changes in circulating blood volume are still required and further studies have to be undertaken to standardize the procedure. In conclusion, this study is simple, quick and can be easily carried out in ward settings. The results by the study and blood volume estimated according to weight are comparable. The total time for single estimate of circulating blood volume is only in the order of 1 min after injecting the radiotracer and the accuracy of the method is sufficient for clinical purposes. Hence this study of estimating circulating blood
1073
burns 33 (2007) 1072–1073
Table 1 – Blood volume estimation in subjects under study using radioisotopes Cr-51 Serial no.
Patient no.
C1 standard counts
Cr counts
V1 standard (ml)
1 min
2 min
10 min
V2 ðLÞ ¼ C1CV1 100 100 2
Study group (n = 7) 1 2 3 4 5 6
1 2 3 4 5 6
42461 30804 31004 25470 32280 42260
839 716 719 684 861 928
813 651 654 652 788 864
735 631 615 524 795 872
1 1 1 1 1 1
5.06 4.30 4.31 3.72 3.79 4.55
Control 1
1
42324
780
642
624
1
5.4
Table 2 – Blood volume estimation in subjects under study by weight method Serial no.
Patient no.
Age (year)
Sex
Weight (kg)
Hb (g%)
PCV (%)
Blood volume (L) By weight [3]
Study group 1 2 3 4 5 6 Control 1
By present study
1. 2. 3. 4. 5. 6.
36 38 38 42 22 36
M M M M F F
61 58 72 62 46 51
12.2 15.8 14.2 14.3 13.6 12.1
36.7 45.2 48.6 46.4 36.8 36.7
4.27 4.06 5.04 4.34 3.22 3.57
5.06 4.30 4.31 3.72 3.79 4.55
1.
45
M
75
14.6
48.7
5.25
5.40
volume is a potentially useful clinical tool for monitoring critical patients.
references
[1] Webb AR. Fluid management in intensive care—avoiding hypovolemia. Br J Intens Care 1997;7:59–64. [2] Frienkel N, Screiner GE, Athens JW. Simultaneous distribution of T-1824 and 131iodine-labelled human serum albumin in man. Lab Clin Invest 1953;32: 138–48. [3] ICSH. Interpretation of measured red cell mass and plasma volume in adults: expert panel on radionuclides of the international council for standardization in hematology. Br J Haematol 1995;89:748–56.
Pramod Kumar* Department of Burns and Plastic Surgery, Kasturba Medical College, Manipal 576104, Karnataka, India
Rajesh Kumar Nandini Pandit Department of Nuclear Medicine, Kasturba Medical College, Manipal 576104, Karnataka, India Amit Aggrawal Kasturba Medical College, Manipal 576104, Karnataka, India Prathap M. Baby Department of Physiology, Melaka-Manipal Medical College (Manipal Campus), International Centre for Health Sciences, India *Corresponding author. Tel.: +91 8202571201x22135 E-mail address: [email protected] (P. Kumar) 0305-4179/$32.00 # 2007 Elsevier Ltd and ISBI. All rights reserved. doi:10.1016/j.burns.2007.03.006