Overview
Definition:
Exchange transfusion is a life-saving procedure where a neonate's blood is systematically replaced with donor blood
It is primarily used to rapidly lower serum bilirubin levels and remove toxins from the circulation.
Epidemiology:
Neonatal hyperbilirubinemia affects up to 60% of term and 80% of preterm infants
Exchange transfusion is indicated in a small but significant percentage of these infants when phototherapy is insufficient and bilirubin levels are critically high.
Clinical Significance:
Exchange transfusion is crucial for preventing severe neurological sequelae like kernicterus, which can result from untreated, severe hyperbilirubinemia
Prompt and appropriate use of this procedure significantly improves patient outcomes.
Indications
Indications For Exchange Transfusion:
Exchange transfusion is indicated in neonates with hyperbilirubinemia that is not responding to phototherapy or when serum bilirubin levels are critically high
Specific indications include: Total serum bilirubin (TSB) levels reaching or exceeding 20 mg/dL in term infants or 15 mg/dL in preterm infants, especially if TSB is rising rapidly (e.g., >0.5 mg/dL per hour) despite intensive phototherapy
Evidence of bilirubin encephalopathy (acute or chronic)
Hemolytic disease of the newborn (HDN) due to Rh incompatibility, ABO incompatibility, or other blood group incompatibilities, with rising TSB levels or signs of anemia and hydrops fetalis
Certain metabolic disorders or intoxications where the offending agent can be removed by exchange.
Timing Of Intervention:
The decision to perform an exchange transfusion is guided by established nomograms for TSB levels based on postnatal age and risk factors
Aggressive management is warranted in the presence of risk factors such as prematurity, sepsis, acidosis, hypoalbuminemia, and clinical signs of neurological dysfunction.
Role Of Phototherapy:
Phototherapy is the first-line treatment for neonatal hyperbilirubinemia
Exchange transfusion is reserved for cases where phototherapy fails to prevent bilirubin levels from reaching exchange transfusion thresholds or when there are signs of encephalopathy.
Preparation
Informed Consent:
Obtain informed consent from parents or legal guardians after explaining the procedure, its benefits, risks, and alternatives
Document the discussion and consent meticulously.
Equipment Setup:
Ensure availability of sterile equipment including sterile gloves, drapes, syringes (e.g., 5 mL, 10 mL, 20 mL), feeding tubes, umbilical catheterization tray, umbilical cord clamps, and a radiant warmer with resuscitation equipment
Have adequate lighting for visualization.
Donor Blood Selection:
Use fresh, compatible donor blood
For Rh-negative infants, use Rh-negative, antibody-screened red blood cells
For ABO incompatibility, use group O red blood cells if the infant is group A or B, or crossmatch the donor red blood cells with the infant's serum
If the infant is group O, use group O red blood cells
Fresh blood (less than 7 days old) is preferred to minimize potassium and acidosis risks.
Patient Stabilization:
Ensure the infant is hemodynamically stable
Obtain vital signs, blood glucose, and baseline laboratory tests including TSB, direct and indirect bilirubin, complete blood count (CBC), blood type, Rh factor, and direct antiglobulin test (DAT)
If sepsis is suspected, initiate antibiotics
Ensure adequate intravenous access, preferably via umbilical venous catheter (UVC) or peripheral venous catheter.
Monitoring Requirements:
Continuous cardiorespiratory monitoring and pulse oximetry are essential
Maintain strict aseptic technique
Prepare for potential complications such as apnea, bradycardia, hypothermia, and fluid overload.
Procedure Technique
Method Of Exchange:
The most common method is the push-pull technique using a double-syringe or a three-way stopcock, typically through umbilical venous catheters
Gradual removal and replacement of small aliquots (e.g., 5-10 mL per kg) minimize circulatory stress.
Volume Of Exchange:
The recommended volume for a total exchange transfusion is approximately twice the infant's total blood volume (around 160-180 mL/kg).
Monitoring During Procedure:
Monitor heart rate, respiratory rate, blood pressure, and oxygen saturation closely throughout the procedure
Check TSB levels every 4-8 hours post-procedure
Monitor for signs of hypoglycemia, hypocalcemia, and hyperkalemia
Obtain post-exchange CBC and TSB levels.
Complication Management:
Be prepared to manage complications like apnea, bradycardia, hypotension, hypocalcemia (administer calcium gluconate if needed), hyperkalemia, and arrhythmias
Rapidly stop the exchange if significant instability occurs.
Complications
Early Complications:
Apnea
bradycardia
hypothermia
hypotension
hypocalcemia
hyperkalemia
arrhythmias
hypoglycemia
thrombocytopenia
emboli (air or clot)
graft-versus-host disease (rare).
Late Complications:
Splenic infarction
portal vein thrombosis
post-exchange anemia
infection (bacterial or viral transmission from donor blood)
necrotizing enterocolitis.
Prevention Strategies:
Meticulous aseptic technique
use of fresh, compatible blood
careful monitoring of vital signs and electrolytes
slow and controlled exchange rate
adequate warming
appropriate fluid management.
Key Points
Exam Focus:
Understand the indications for exchange transfusion, particularly TSB thresholds and rate of rise
Know the preparatory steps, including donor blood selection and patient stabilization
Be familiar with the push-pull technique and the management of common complications.
Clinical Pearls:
Always consider the infant's clinical status and risk factors beyond just the TSB level
Hypoalbuminemia <3 g/dL is a risk factor for neurotoxicity
Consider using a central venous catheter (UVC) for better stability and access
If performing a partial exchange, ensure it's for specific indications like severe anemia or hyperkalemia.
Common Mistakes:
Delaying the procedure when indicated
using incompatible blood
failing to monitor electrolytes and calcium
inadequate volume of exchange
poor aseptic technique leading to infection
not preparing for potential complications.