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Answer: B
In children as in adults, the primary and secondary surveys identify injuries and guide rapid intervention. This boy
presents with blunt abdominal trauma, abnormal vital signs, and an abnormal abdominal examination. He is found to have a high-grade liver laceration with hemodynamic compromise, prompting large-volume blood transfusion. As the non-operative management of pediatric solid organ trauma becomes more common, the emergency physician must be familiar with methods to optimize the child’s hemodynamic status, often for prolonged periods of time. In this case, the task is to transfuse and closely monitor hemodynamics
to ensure that this boy is still safe to remain a non-operative candidate.
A review of a few fast facts before we move forward:
● Whole blood is 45% red cells and 55% plasma (platelets and WBCs are < 1% of volume)
● Total blood volume in children changes with age: in neonates, 90 mL/kg; children 80 mL/kg; adolescents and
adults, 70 mL/kg.
● The adult male has approximately 5 L total blood volume (70 kg x 70 mL/kg = 4900 mL)
● The recommended emergent blood transfusion dose in ATLS or PALS is 10 mL/kg.
Let’s use the above to construct a transfusion plan for our acutely injured boy:
Given the above proportions, the initial dose of 10 mL/kg of packed red blood cells (PRBCs) is equivalent to replacing 22 mL/kg blood volume (after equilibrium is reached with tissue fluid following transfusion – this is a quantitative equivalent, not a qualitative equivalent, as there is an inherent dilution in important blood components such as plasma proteins).
For sake of simplification, let’s say that the recommended transfusion of 10 mL/kg PRBCs effectively replaces 20 mL/kg blood volume. If the child’s total blood volume is 80 mL/kg, then the 10 mL/kg PRBC dose – corresponding effectively to 20 mL/kg volume – will replace ¼ of the child’s total blood volume. Four doses of 10 mL/kg PRBCs effectively replaces his total blood volume.
This is where massive transfusion comes in: various protocols exist to approximate replacing blood volume both
quantitatively and qualitatively (replacing plasma proteins and platelets) to avoid coagulopathy. Adult and
pediatric protocols vary by institution (ratio of products varies) and are currently undergoing clinical investigation.
PRBCs are stored in a citrate solution, which can cause hypocalcemia and metabolic alkalosis in vivo. RBCs
age rapidly, and leach potassium (the RBC membrane ATPase is inhibited at refrigerator temperatures, and potassium is not pumped back into the cell). In adults, this is rarely a problem, unless the patient is severely renally impaired.
In children, however, the age of PRBCs correlates with worsening outcomes. At 30 days (which is particularly old
in RBC terms), the potassium concentration can peak to 90 mEq/L in PRBCs. Adding to this context is that younger children have a lower urinary excretion of potassium.
This child is experiencing severe hyperkalemia from massive transfusion, demonstrating a wide complex tachycardia now becoming a sine wave:
In children as in adults, the primary and secondary surveys identify injuries and guide rapid intervention. This boy
presents with blunt abdominal trauma, abnormal vital signs, and an abnormal abdominal examination. He is found to have a high-grade liver laceration with hemodynamic compromise, prompting large-volume blood transfusion. As the non-operative management of pediatric solid organ trauma becomes more common, the emergency physician must be familiar with methods to optimize the child’s hemodynamic status, often for prolonged periods of time. In this case, the task is to transfuse and closely monitor hemodynamics
to ensure that this boy is still safe to remain a non-operative candidate.
A review of a few fast facts before we move forward:
● Whole blood is 45% red cells and 55% plasma (platelets and WBCs are < 1% of volume)
● Total blood volume in children changes with age: in neonates, 90 mL/kg; children 80 mL/kg; adolescents and
adults, 70 mL/kg.
● The adult male has approximately 5 L total blood volume (70 kg x 70 mL/kg = 4900 mL)
● The recommended emergent blood transfusion dose in ATLS or PALS is 10 mL/kg.
Let’s use the above to construct a transfusion plan for our acutely injured boy:
Given the above proportions, the initial dose of 10 mL/kg of packed red blood cells (PRBCs) is equivalent to replacing 22 mL/kg blood volume (after equilibrium is reached with tissue fluid following transfusion – this is a quantitative equivalent, not a qualitative equivalent, as there is an inherent dilution in important blood components such as plasma proteins).
For sake of simplification, let’s say that the recommended transfusion of 10 mL/kg PRBCs effectively replaces 20 mL/kg blood volume. If the child’s total blood volume is 80 mL/kg, then the 10 mL/kg PRBC dose – corresponding effectively to 20 mL/kg volume – will replace ¼ of the child’s total blood volume. Four doses of 10 mL/kg PRBCs effectively replaces his total blood volume.
This is where massive transfusion comes in: various protocols exist to approximate replacing blood volume both
quantitatively and qualitatively (replacing plasma proteins and platelets) to avoid coagulopathy. Adult and
pediatric protocols vary by institution (ratio of products varies) and are currently undergoing clinical investigation.
PRBCs are stored in a citrate solution, which can cause hypocalcemia and metabolic alkalosis in vivo. RBCs
age rapidly, and leach potassium (the RBC membrane ATPase is inhibited at refrigerator temperatures, and potassium is not pumped back into the cell). In adults, this is rarely a problem, unless the patient is severely renally impaired.
In children, however, the age of PRBCs correlates with worsening outcomes. At 30 days (which is particularly old
in RBC terms), the potassium concentration can peak to 90 mEq/L in PRBCs. Adding to this context is that younger children have a lower urinary excretion of potassium.
This child is experiencing severe hyperkalemia from massive transfusion, demonstrating a wide complex tachycardia now becoming a sine wave:
Immediate cardiac membrane stabilization with 20 mg/kg calcium chloride (or 60 mg/kg calcium gluconate) over 3-5 minutes (or pushed over 10 seconds in arrest) will serve as a temporizing measure while other standard therapies for hyperkalemia are initiated (insulin/glucose, inhaled β-agonist, sodium bicarbonate, resin binder).
Hemodialysis is a definite option (D) as a follow-up therapy (especially if there is evidence of acidosis), but action must be taken now.
In trauma, abrupt deterioration prompts the physician to consider missed or worsening injuries (especially large vessel or retroperitoneal injuries). However, in the absence of tamponade physiology, a thoracotomy to gain access to the heart (A) will not address his most life-threating issue – in this case, a “medical” etiology (rather than
“surgical” etiology).
Bottom line:
● Give PRBCs when needed and consider replacing plasma and platelets when larger volumes are
required.
● Children are much more susceptible to symptomatic hyperkalemia after emergent blood transfusion than
adults.
● Remember that trauma resuscitations, like medical resuscitations, are a dynamic process; medical and
traumatic etiologies may coincide.
References
Henrickson JE et al. Implementation of a pediatric trauma massive transfusion protocol: one institution’s experience. Transfusion. 2012; 52:1228-1236.
Pluijmen MJHM, Hersbach FMRJ. Hyperkalemia Sine-Wave Pattern Arrhythmia and Sudden Paralysis That Result From Severe Hyperkalemia. Circulation. 2007;116:e2-e4
Hemodialysis is a definite option (D) as a follow-up therapy (especially if there is evidence of acidosis), but action must be taken now.
In trauma, abrupt deterioration prompts the physician to consider missed or worsening injuries (especially large vessel or retroperitoneal injuries). However, in the absence of tamponade physiology, a thoracotomy to gain access to the heart (A) will not address his most life-threating issue – in this case, a “medical” etiology (rather than
“surgical” etiology).
Bottom line:
● Give PRBCs when needed and consider replacing plasma and platelets when larger volumes are
required.
● Children are much more susceptible to symptomatic hyperkalemia after emergent blood transfusion than
adults.
● Remember that trauma resuscitations, like medical resuscitations, are a dynamic process; medical and
traumatic etiologies may coincide.
References
Henrickson JE et al. Implementation of a pediatric trauma massive transfusion protocol: one institution’s experience. Transfusion. 2012; 52:1228-1236.
Pluijmen MJHM, Hersbach FMRJ. Hyperkalemia Sine-Wave Pattern Arrhythmia and Sudden Paralysis That Result From Severe Hyperkalemia. Circulation. 2007;116:e2-e4