Scientific Articles
The Use of an Oxygen Dissociation Curve Analyzer in Transfusion Therapy R. S. FESTAA N D T. ASAKURA From the Children's Hospiiul of Philadelphiu. Divisions of Pediatric Oncology and Hematology, Philudelphiu, Pennsylvuniu
Two automatic apparatuses utilizing a dual wavelength spectrophotometric method were developed to perform oxygen dissociation curves on microsamples of blood. This method provides a complete printout of an oxygen disociatlon curve in 15 to 20 minutes and the P,, values obtained agree closely with those obtained by classical methods. This technique was used as part of a routine clinical evaluation in assessing oxygen delivery in anemic patients. These apparatuses allowed Identification of patients with well-compensated anemia, patients with no compensatory decrease in oxygen afnnlty, and several patients with a paradoxical increase in oxygen affinity. Knowledge of the oxygen-releasing capacity of the blood permits a more thorough evaluation of oxygen transport in anemic patients than the hemoglobin level and a more precise assessment of the need for transfusion therapy. The ready availability of an oxygen dissociation curve by this method is feasible for routine clinical evaluation and permits more judicious use of blood products.
THEPRINCIPAL REASON for transfusion of red blood cells is to correct anemia so that adequate oxygen may be delivered to tissues. Although the requirement for blood transfusion is generally determined on the basis of clinical symptomatology and the hemoglobin level, a more meaningful basis than the hemoglobin level would be the oxygen-delivering capacity of the patient's blood as measured by the oxygen dissociation curve (ODC). An important compensatory mechanism in anemia which helps to offset the reduced oxygen-carrying capacity of the blood involves a reduced affinity of hemoglobin for oxygen mediated by an increase Supported by grant CA 19372 from the National Cancer Institute and by grants HL-18226 and NHLI72-2%2B from the National Institutes of Health. Received for publication February IS, 1978;accepted June 25, 1978.
in red blood cell 2,3-diphosphoglycerate (2,3-DPG).8,14 With moderate anemia, this mechanism allows a greater fraction of oxygen to be released at any given oxygen tension and minimizes the necessity for an increase in cardiac output and a decrease in tissue oxygen tension.' Despite the importance of the ODC in providing information concerning oxygen transport, methods to assess the affinity of hemoglobin for oxygen are not readily available. The methods usually used to determine the position of the ODC involve tonometry and mixing techniques*which are time consuming, tedious, require attention to several variables, and usually require a considerable amount of blood. For these reasons, the measurement of the ODC is not usually done in clinical laboratories. To measure the ODCs in the anemic children on the pediatric oncology service, we used two automatic ODC apparatuses which draw a continuous ODC from full oxygenation to deoxygenation at controlled conditions of pH and temperature using as little as 0.1 ml of blood. The curve can be completed in 15 to 20 minutes. The oxygenreleasing capacity of the blood as calculated from the ODC and hemoglobin level was used along with the clinical evaluation to serve as a guideline for transfusion therapy in these patients. Materials and Methods Thirty-nine anemic children w h o had a variety of malignant conditions were divided into four
0041-1132/79/0300/0107 $00.85 0 J. B. Lippincott Co. Transfusion March-April 1979
I07
Volume 19 Number 2
Transfusion MarchApril 1979
FESTA AND ASAKURA
108
Table 1. Oxygen Transport and Unloading in Anemic Patients Oxygen Released at Venous
Blood Oxygen No.
Controls
of Pa-
Level of
Relation to
Heme globin
Carrying Capacity
tients
Activity'
Transfusion
(g1dI)
(Val.%)
26
Normal ~
Group I
Group II
6
8
14
-
14.5 1.4
8
3
40 rnm Hg
PO* Venous
rnl RBC)
(Vo1.k)
PH
2
2
27.0 1.1
f
4.478 0.336
2
4.8 0.4
No transfusion given
79 r 1 0
11 0 211
34 4 207
2
7 460 0440
38 202
7,41 r 002 (n = 5)
No transfusion given
7.3 r 0.7
10.1 r 1.0
2
9.8 1.0
2
15.7 0.8
2
10.0 1.2
2
17.2 1.0
2
~~
A
A
B(12) C(2)
B(1) C(7)
Extreme fatigue
7.1
Pretransfusion
f 0.6
2
11.3 0.6
2
7.2 0.9
2
12.4 0.8
2
2
Pretransfusion 2
Posttransfusion Group IV
(mm Hg)
2.3-DPG (umoled
2
Posttransfusion Group Ill
20.2 1.9
P.,
2
5.949 f
3.1 0.3
7.39 0.03 (n = 4)
30.7 0.8
2
5.901 0.791
2
3.0 0.3
7.38 0.03 (n = 7)
27.6 2.2
2
0.843
2
4.0 0.6
26.7 1.5
2
0.460
2
2.5 0.3
24.7 1.6
2
3.596 0.560
2
3.7 0.4
2
2.0 0.3
f
3.8 0.5
4.603
4.328
10.4
21.3
2.431
r 1.1
f 2.2
r 0.513
11.8 0.3
16.9
24.3
3.473
f 1.5
f 1.5
f 0.420
2
* A-Normal or minimal decrease. 0-Moderate Marked decrease.
f 0.720
7.5 0.8
Pretransfusion
Posttransfusion
30.9 0.6
2
decrease. C-
groups based on the P,, value of their ODCs. Group I had very high P,, values (>33.0 mm Hg), Group I1 had elevated P,, values (29.5-33.0 mm Hg), Group I11 had normal Ps0 values (25.0-29.0 mm Hg) and Group IV had low P,, values (
The Use of an Oxygen Dissociation Curve Analyzer in Transfusion Therapy R. S. FESTAA N D T. ASAKURA From the Children's Hospiiul of Philadelphiu. Divisions of Pediatric Oncology and Hematology, Philudelphiu, Pennsylvuniu
Two automatic apparatuses utilizing a dual wavelength spectrophotometric method were developed to perform oxygen dissociation curves on microsamples of blood. This method provides a complete printout of an oxygen disociatlon curve in 15 to 20 minutes and the P,, values obtained agree closely with those obtained by classical methods. This technique was used as part of a routine clinical evaluation in assessing oxygen delivery in anemic patients. These apparatuses allowed Identification of patients with well-compensated anemia, patients with no compensatory decrease in oxygen afnnlty, and several patients with a paradoxical increase in oxygen affinity. Knowledge of the oxygen-releasing capacity of the blood permits a more thorough evaluation of oxygen transport in anemic patients than the hemoglobin level and a more precise assessment of the need for transfusion therapy. The ready availability of an oxygen dissociation curve by this method is feasible for routine clinical evaluation and permits more judicious use of blood products.
THEPRINCIPAL REASON for transfusion of red blood cells is to correct anemia so that adequate oxygen may be delivered to tissues. Although the requirement for blood transfusion is generally determined on the basis of clinical symptomatology and the hemoglobin level, a more meaningful basis than the hemoglobin level would be the oxygen-delivering capacity of the patient's blood as measured by the oxygen dissociation curve (ODC). An important compensatory mechanism in anemia which helps to offset the reduced oxygen-carrying capacity of the blood involves a reduced affinity of hemoglobin for oxygen mediated by an increase Supported by grant CA 19372 from the National Cancer Institute and by grants HL-18226 and NHLI72-2%2B from the National Institutes of Health. Received for publication February IS, 1978;accepted June 25, 1978.
in red blood cell 2,3-diphosphoglycerate (2,3-DPG).8,14 With moderate anemia, this mechanism allows a greater fraction of oxygen to be released at any given oxygen tension and minimizes the necessity for an increase in cardiac output and a decrease in tissue oxygen tension.' Despite the importance of the ODC in providing information concerning oxygen transport, methods to assess the affinity of hemoglobin for oxygen are not readily available. The methods usually used to determine the position of the ODC involve tonometry and mixing techniques*which are time consuming, tedious, require attention to several variables, and usually require a considerable amount of blood. For these reasons, the measurement of the ODC is not usually done in clinical laboratories. To measure the ODCs in the anemic children on the pediatric oncology service, we used two automatic ODC apparatuses which draw a continuous ODC from full oxygenation to deoxygenation at controlled conditions of pH and temperature using as little as 0.1 ml of blood. The curve can be completed in 15 to 20 minutes. The oxygenreleasing capacity of the blood as calculated from the ODC and hemoglobin level was used along with the clinical evaluation to serve as a guideline for transfusion therapy in these patients. Materials and Methods Thirty-nine anemic children w h o had a variety of malignant conditions were divided into four
0041-1132/79/0300/0107 $00.85 0 J. B. Lippincott Co. Transfusion March-April 1979
I07
Volume 19 Number 2
Transfusion MarchApril 1979
FESTA AND ASAKURA
108
Table 1. Oxygen Transport and Unloading in Anemic Patients Oxygen Released at Venous
Blood Oxygen No.
Controls
of Pa-
Level of
Relation to
Heme globin
Carrying Capacity
tients
Activity'
Transfusion
(g1dI)
(Val.%)
26
Normal ~
Group I
Group II
6
8
14
-
14.5 1.4
8
3
40 rnm Hg
PO* Venous
rnl RBC)
(Vo1.k)
PH
2
2
27.0 1.1
f
4.478 0.336
2
4.8 0.4
No transfusion given
79 r 1 0
11 0 211
34 4 207
2
7 460 0440
38 202
7,41 r 002 (n = 5)
No transfusion given
7.3 r 0.7
10.1 r 1.0
2
9.8 1.0
2
15.7 0.8
2
10.0 1.2
2
17.2 1.0
2
~~
A
A
B(12) C(2)
B(1) C(7)
Extreme fatigue
7.1
Pretransfusion
f 0.6
2
11.3 0.6
2
7.2 0.9
2
12.4 0.8
2
2
Pretransfusion 2
Posttransfusion Group IV
(mm Hg)
2.3-DPG (umoled
2
Posttransfusion Group Ill
20.2 1.9
P.,
2
5.949 f
3.1 0.3
7.39 0.03 (n = 4)
30.7 0.8
2
5.901 0.791
2
3.0 0.3
7.38 0.03 (n = 7)
27.6 2.2
2
0.843
2
4.0 0.6
26.7 1.5
2
0.460
2
2.5 0.3
24.7 1.6
2
3.596 0.560
2
3.7 0.4
2
2.0 0.3
f
3.8 0.5
4.603
4.328
10.4
21.3
2.431
r 1.1
f 2.2
r 0.513
11.8 0.3
16.9
24.3
3.473
f 1.5
f 1.5
f 0.420
2
* A-Normal or minimal decrease. 0-Moderate Marked decrease.
f 0.720
7.5 0.8
Pretransfusion
Posttransfusion
30.9 0.6
2
decrease. C-
groups based on the P,, value of their ODCs. Group I had very high P,, values (>33.0 mm Hg), Group I1 had elevated P,, values (29.5-33.0 mm Hg), Group I11 had normal Ps0 values (25.0-29.0 mm Hg) and Group IV had low P,, values (
