A new method for calculating volumes of blood required for partial exchange transfusion

86

Brief clinical and laboratory observations

REFERENCES

1. di Sant'Agnese PA: Cystic fibrosis of the pancreas, Am J Ivied 21:406, 1956. 2. Oppenheimer EH: Focal necrosis of striated muscle in an infant with cystic fibrosis of the pancreas and evidence of lack of absorption of fat-soluble vitamins, Bull Johns Hopkins Hasp 9~:353, 1956. 3. Andersen DH: Cystic fibrosis of the pancreas, vitamin A deficiency, and bronchiectasis, J PEDIATR15:763, 1939. 4. Parsons LG: Bone changes occurring in renal and coeliac infantilism and their relationships to rickets: coeliac rickets, Arch Dis Child 2:198, 1927. 5. Weber A, and Roy CC: The malabsorption associated with chronic liver disease in children, Pediatrics 50:73, 1972. 6. Thussig LM, Kattwinkel J, Friedewald WT, and di Sant'Agnese PA: A new prognostic score and clinical evaluation system for cystic fibrosis, J PEDI^TR 82:380, 1973.

The Journal of Pediatrics January 1979

7. Belsey RE, De Luca HF, and Potts JT: A rapid assay for 25-OH-vitamin D3 without preparative chromatography, J Clin Endocrinol Metab 38:1046, 1974. 8. Farrell PM, and di Sant'Agnese PA: Vitamin D levels in the serum of cystic fibrosis patients, Pediatr Res 11:443, 1977. 9. Arnaud SB, Stickler GB, and Haworth JC: Serum 25hydroxyvitamin D in infantile rickets, Pediatrics 57:221, 1976. 10. Haddad JG, and Hahn TJ: Natural and synthetic sources of circulating 25-hydroxyvitamin D in man, Nature 244:515, 1973. 11. Thompson GR, Lewis B, and Booth CC: Absorption of vitamin D3-3H in control subjects and patients with intestinal malabsorption, J Clin Invest 45:94, 1966. 12. Blomstrand R, and Forsgren L: Intestinal absorption and esterification of vitamin D3-1,2-3H in man, Acta Chem Scand 21:1662, 1967.

A new method for calculating volumes of blood required for partial exchange transfusion Brian Berman, M.D., Abba Krieger, Ph.D, and J. Lawrence Naiman, M.D.,* Philadelphia, Pa.

P A R T I A L E X C H A N G E T R A N S F U S I O N is a n effective

and rapid method of correcting severe anemia in patients unable to tolerate the increased intravascular volume associated with conventional transfusion t h e r a p y ? 2 It is an especially useful technique in patients with clinical manifestations of congestive heart failure secondary to a markedly reduced red blood cell mass?- ~ The utility of partial exchange transfusion in the pediatric population has been well documented. 5-7 A problem in using this procedure in children is the estimation of the volume of exchange blood required to achieve a desired increase in the level of hemoglobin (or hematocrit). In the paper by Nieburg and Stockman, ~ a formula for estimation of partial exchange volume was presented, based on the assumption that the increase in hemoglobin concentration during the course of the procedure is a linear function of the volume exchanged. In fact, however, the incremental change in hemoglobin concentration during exchange transfusion is greatest during the early phase and progressively diminishes during the course of blood exchange?

With this in mind we have developed a mathematical formula that incorporates these hemodynamic considerations, theoretically yielding a more precise estimate of the required exchange volume. Although the method was developed originally for use in transfusion of children with severe anemia, it can be used also to estimate the exchange volumes needed for reduction of hematocrit levels in symptomatic polycythemia? METHOD The technique of partial exchange transfusion involves repeated cycles of withdrawal of a fixed volume of patient's blood and replacement with donor red blood cells via a single intravenous catheter. To maximize efficiency within the limits of patient safety, the volume of each cycle of withdrawal and infusion is approximately 5% of estimated blood volume; this may vary at times, based on the age and sex of the patient, and on technical factors. The hematocrit value at any time during the course of the procedure may be expressed as follows: H . = H d -- (H. - H ~ ) ( V ~ -

From St. Christopher's Hospital for Children, The Department of Pediatrics, Temple University School of Medicine and the Department of Statistics, The Wharton School, University of Pennsylvania. *Reprint address: St. Christopher's Hospitalfor Children, 2600 N, Lawrence St., Philadelphia, P,4 19133.

V.) ~*

V,

where, Hn = hematocrit after "n" cycles of withdrawal/ infusion; Hd ffi hematocrit of donor blood; H, = hematocrit of patient initially: Vt = estimated total blood *Derivationavailableon request.

0022-3476/79/100086 + 04500.40109 1979 The C. V. Mosby Co.

Volume 9 4 Number 1

Brief clinical and laboratory observations

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Brief clinical and laboratory observations

The Journal of Pediatrics January 1979

Table. Patient data

Patient l 2 3 4 5

Weight (kg)

V~ (ml)

2.3 f 3.0 l 3.2 36.8 2 1.97

200 240 260 2760 180 200

I

V~ [ (ml)

1

10 15 15 60 10 10

F

H, (%)

0.05 0.0625 0.06 0.0217 0.055 0.05

35 24 20 60 23 18

volume of patient; V~ = volume of each withdrawal/ infusion. In an effort to simplify the above formula for clinical application, a further derivation was carried out. This has yielded a composite hematocrit ratio which upon entry on a semi-logarithmic graph (Figure) enables one to determine the total number of withdrawal/infusion cycles, "n," necessary to achieve a desired increase in hematocrit level by partial exchange transfusion. Employing the simple calculation: Hd - Hr, Ho - H~ where Hr = final desired hematocrit of patient (Ha and H~ as above), and "F" = the fraction of patient's total blood volume exchanged per cycle (VJVt), one may readily derive "n." In the polycythemic patient the method is similar, except that the donor hematocrit (Ha) is zero if plasma is used as the infusate.

Sample calculation. Patient's body weight = 10 kg Estimated total blood volume (V,) = 10 kg • 75 ml/kg = 750 ml Volume per withdrawal/infusion cycle (V~) = 30 ml (arbitrarily) F = 30 ml = 0.04 750 ml H~ --- 10% Hf = 30% H~ = 60% H~-H, ~ = 0.60 H,~- H~ Using the graphic expression applicable when F = 0.04, one may readily derive n, the number of withdrawal/infusion cycles of 30 ml each to achieve Hr. In this case, n works out to approximately 121/2,and the total volume of the partial exchange transfusion is therefore 121/2 • 30 ml = 375 ml (approximately).

Predicted Hf(%) 50 40 45 55 45 45

Hd (%) 75 84 75 0 94 82

nd-n f

Measured Hf(%)

Hd-Hi 0.625 0.733 0.537 0.833 0.694 0.578

9% 5 989 488 7 11

54 36 44 53.8 47 44

PATIENT DATA Partial exchange transfusion was performed on six occasions in five patients utilizing the method described above. The pertinent data are shown in the Table. Four of the patients were newborn infants with severe anemia in whom it was felt that tissue hypoxia could not be corrected rapidly enough without risking volume overload. The fifth patient (No. 3) was severely hypoxic owing to cardiopulmonary failure from cystic fibrosis. Erythropheresis was carried out using fresh frozen plasma to reduce the elevated red cell mass and perhaps to improve pulmonary blood flow; there was transient subjective improvement after the procedure. The route of exchange in the newborn infants was the umbilical artery or vein; in Patient 2 the second exchange (at 11 days of age) had to be carried out using separate peripheral intravenous lines, alternating the infusion and withdrawal phases. In the older patient (No. 3) the exchange was accomplished through a single 18 gauge Butterfly needle (Abbott Laboratories, Inc., N. Chicago, I11.) placed in an antecubital vein. The time required to complete the partial exchange transfusion was less than 30 minutes in all of the patientS. No serious complications occurred during the procedure, except in Patient 4 who had two episodes of profound bradycardia. Severe acidosis was present prior to the exchange in that patient; following repletion of his hemoglobin mass there was substantial improvement in his clinical status. From the results shown in the Table, it is clear that there was excellent agreement between the final measured hematocrits and the hematocrits predicted from our formula. COMMENT The method described herein is theoretically sound. and applicable through the range of hematocrit values encountered in severe anemia and polycythemia from birth into the second decade of life. Syringe sizes from l0

Volume 94 Number 1

B r i e f clinical and laboratory observations

to 50 ml are acceptable; the choice depends largely on the size of the patient. From the points of view of safety and efficiency, the optimal syringe size is one that can accommodate a cycle volume that yields an F value nearest 0.05 (i.e., 5% of estimated total blood volume). In older patients the F values are of necessity in the range of 0.02 to 0.01, because of the limitation imposed by a maximum syringe volume that is small in relation to patient blood volume. As a result, the number of cycles (n) may become unacceptably large. Should this become a practical limitation, the technique of exchange may be changed to one using simultaneous infusion and withdrawal with standard plastic blood bags connected to separate intravenous sites. Additional considerations when employing the method presented include estimation of total blood volume of the patient. In the normal newborn infant this is considered to be in the range of 85 to 100 ml/kg, depending upon gestational age. Among older infants and children, normal blood volume was considered to be 75 ml/kg. Patients with polcythemia secondary to cyanotic congenital heart disease may have blood volumes in excess of 100 ml/kg." The hematocrit value of donor packed red blood cells varied substantially in our series; it is recommended, therefore, that this be measured prior to final calculation of the required volume of donor blood. Review of patient data presented in two reports ='. ~ of severely anemic children suggests good agreement with

89

data predicted by our formula. Further experience by others is encouraged to validate the results reported here. We thank Drs. David Rubinstein, Eileen Tyrala, and Jeanne Manser of the Intensive Care Nurseries of St. Christopher's Hospital for Children and Temple University Hospital for allowing us to study the infants under their care. REFERENCES 1. Ward T: Exchange transfusion in severe anemia, Br Med J 1:631, 1952. 2. Fullerton WT, and Turner AG: Exchange transfusion in the treatment of severe anemia of pregnancy, Lancet 1:75, 1962. 3. Cutting HO, and Marlow AA: Partial exchange transfusion in severe chronic anemia, Arch Intern Med 117:478, 1966. 4. Editorial, Lancet 2:270, 1966. 5. Purugannan HB, and Naiman JL: Exchange transfusion in severe iron deficiency anemia prior to emergency surgery, J PEDIATR 69:804, 1966. 6. Stubbs PA, and Avery GB: Partial exchange transfusion-a treatment procedure for severe non-hemolytic anemia in newborns, Clin Pediatr 6:301, 1967. 7. Nieburg PI, and Stockman JA: Rapid correction of anemia with partial exchange transfusion, Am J Dis Child 131:60, 1977. 8. Naiman JL: Polycythemia, in G-ellisSS, and Kagan BM: Current pediatric therapy, Vol 6, Philadelphia, 1973, WB Saunders Company, pp 268-9. 9. Rosenthal A, Nathan DG, Marty AT, Button LN, Miettinen OS, and Nadas AS: Acute hemodynamic effects of red cell volume reduction in polycythemia of cyanotic congenital heart disease, Circulation 42:297, 1970.

Lethal hypoglycemia in a child with a deficiency of 3-hydroxy-3-methylglutarylcoenzyme A lyase Ruud B. H. Schutgens, Ph.D., Hugo Heymans, M.D., Arnold Ketel, M.D., Heln A. Veder, Amsterdam, The Netherlands, Marinus Duran, Ph.D., Dirk Ketting, and Sybe K. Wadman, Ph.D., Utrecht, The Netherlands

THE CLINICAL AND BIOCHEMICAL ASPECrS of three inborn errors of leucine metabolism-maple syrup urine disease, isovaleric acidemia, and 3-methylcrotonylglycinuria-have been well defined. The clinical pattern From the Paediatric Clinic Academic Hospital of the University of Amsterdam and University Children's Hospital "Het Wilhelmina Kinderziekenhuis. '" Reprint address: Paediatrie Clinic Academic Hospital of the University of Amsterdam, Binnengasthuis, Grimburgwal 10, Amsterdam. The Netherlands.

0022-3476/79/100089 + 03500.30/0 9 1979 The C. V. Mosby Co.

includes intermittent metabolic acidosis and ketosis, feeding difficulties, and neurologic abnormalities of varying degree.' Recently a fourth defect of leucine metabolism, Abbreviations used: HMG-CoA: 3-hydroxy-3-methylglutarylcoenzyme A 3,GT: gamma glutamyl transpeptidase 3-hydroxy-3-methylglutaryl-CoA lyase deficiency, was discovered._~. 3 In this disease hypoglycemia and a characteristic excretory pattern of organic acids, including