SURFACTANT REPLACEMENT THERAPY by Dr.Nadeem Sahibzada

SURFACTANT REPLACEMENT THERAPY: 

SURFACTANT REPLACEMENT THERAPY Dr. Nadeem-Ur-Rasool DCH Trainee

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Surfactant is natural endogenous compound forming a layer between alveolar surface and the alveolar gas thus reducing surface tension within the alveoli ,so preventing alveolar collapse on expiration. Surfactant deficiency causes Respiratory Distress Syndrome. Direct tracheal instillation of surfactant has been shown to reduce mortality & morbidity in infants with RDS.

Types Of Surfactant: 

Types Of Surfactant Bovine * From animal Lung Lavage * From human amniotic fluid Synthetic Produced from synthetic materials

Commercial Preparations: 

Commercial Preparations Type Source Composition Dosing Comments Beractant ( Survanta ) Bovine lung mince Dipalmitoyl phosphatidylcholine (DPPC), tripalmitin , SP-B < 0.5%, SP-C 99% of TP wt/wt 4mL/kg (100mg/kg), 1-4 doses every 6h Refrigerate Bovactant ( Alveofact ) Bovine lung lavage 99% PL, 1% SP-B and SP-C 45mg/ mL From the Federal Republic of Germany Infasurf Calf lung lavage DPPC, tripalmitin , SP-B 290g/ mL , SP-C 360g/ mL 3mL/kg (105mg/kg), 1-4 doses every 6-12h 6mL vials, refrigerate Bovine lipid extract surfactant ( bLES ) Bovine lung lavage 75% phosphatidylcholine (PC) and 1% SP-B and SP-C 135mg/kg/dose (5mL/kg), 1-4 doses every 12h Canadian Colfosceril palmitate ( Exosurf ) Synthetic 85% DPPC, 9% hexadecanol , 6% tyloxapol 5mL/kg (67.5mg/kg), 1-4 doses every 12h No longer available; lyophilized, dissolve in 8mL Lucinactant ( Surfaxin ) Synthetic Protein: KL4 ( sinapultide ) resembles SP-B; Phospholipids: DPPC, palmitoyloleoyl phosphatidylcholine (POPG) 175 mg/kg/dose phospholipid Not licensed by the FDA; Artificial lung expanding compound (ALEC) Synthetic 70% DPPC, 30% unsaturated phosphatidylglycerol No data Discontinued

REPLACEMENT STRATAGIES: 

REPLACEMENT STRATAGIES Prophylactic / Preventive * Shortly after birth or at birth in high risk infants. Therapeutic  *In clinically confirmed RDS

Setting: 

Setting Administered by trained personnel in Delivery room Neonatal intensive care unit

INDICATIONS: 

INDICATIONS Prophylactic administration may be indicated in infants at high risk of developing RDS because of short gestation < 32 weeks or low birth weight < 1,300 g which strongly suggest lung immaturity. infants in whom there is laboratory evidence of surfactant deficiency such as lecithin/ sphingomyelin ratio less than 2:1 or the absence of phosphatidylglycerol. Rescue or therapeutic administration is indicated in preterm or full-term infants who require endo -tracheal intubation and mechanical ventilation because of increased work of breathing as indicated by an increase in respiratory rate, sub- sternal and supra- sternal retractions, grunting, and nasal flaring. increasing oxygen requirements as indicated by pale or cyanotic skin color, agitation, and decreases in PaO2 and have clinical evidence of RDS including chest radiograph characteristic of RDS. mean airway pressure greater than 7 cm H2O to maintain an adequate PaO2.

CONTRAINDICATIONS: 

CONTRAINDICATIONS Relative contraindications to surfactant administration are; the presence of congenital anomalies incompatible with life beyond the neonatal period. Respiratory distress in infants with laboratory evidence of lung maturity.

COMPLICATIONS: 

COMPLICATIONS Procedural Complications; Plugging of endotracheal tube (ETT) by surfactant. Hemoglobin desaturation and increased need for supplemental O2. Bradycardia due to hypoxia. Tachycardia due to agitation, with reflux of surfactant into the ETT. Pharyngeal deposition of surfactant. Administration of surfactant to only one lung. Administration of suboptimal dose secondary to miscalculation or error in reconstitution.

Cont…: 

Cont… Physiologic complications ; Apnea. Pulmonary hemorrhage. Mucus plugs. Increased necessity for treatment for PDA. Marginal increase in retinopathy of prematurity. Barotrauma resulting from increase in lung compliance following surfactant replacement and failure to change ventilator settings accordingly.

LIMITATION OF METHOD: 

LIMITATION OF METHOD ETT placement may not have been verified by chest radiograph in delivery room. Atelectasis and lung injury may occur prior to therapeutic administration. The response may be transient. Positioning recommended for surfactant administration may further compromise the unstable infant.

ASSESSMENT OF NEED: 

ASSESSMENT OF NEED Determine that valid indications are present; Assess lung immaturity prior to prophylactic administration of surfactant by gestational age and birth weight and/or by laboratory evaluation of tracheal or gastric aspirate. Establish the diagnosis of RDS by chest radiographic criteria and the requirement for mechanical ventilation in the presence of short gestation and/or low birth weight.

ASSESSMENT OF OUTCOME: 

ASSESSMENT OF OUTCOME Reduction in O2 requirement. Reduction in work of breathing. Improvement in lung volumes and lung fields as indicated by chest radiograph. Improvement in pulmonary mechanics ( eg , compliance, airways resistance) and lung volume. Reduction in ventilator requirements.

RESOURCES: 

RESOURCES Administration procedures recommended for specific preparations of surfactant should be adhered to Equipment Trained Personnel Clinical Knowledge

Administration equipment. : 

Administration equipment. Syringe containing the ordered dose of surfactant, warmed to room temperature. 5-Fr feeding tube or catheter, or endotracheal tube connector with delivery port. Mechanical ventilator or manual ventilator (resuscitation bag). Resuscitation equipment Laryngoscope and endotracheal tube. Manual resuscitation bag and airway manometer. Blended oxygen source. Suction equipment ( ie , catheters, sterile gloves, collecting bottle and tubing, and vacuum generator). Radiant warmer ready for use. Monitoring equipment Neonatal tidal volume monitor if available. Airway pressure monitor. Pulse oximeter or transcutaneous PCO2 monitor. Cardiorespiratory monitor.

Personnel & Knowledge: 

Personnel & Knowledge Should be performed under the direction of a physician by credentialed personnel who competently demonstrate proper use, understanding, and mastery of the equipment and technical aspects of surfactant replacement therapy. Comprehensive knowledge and understanding of neonatal ventilator management and pulmonary anatomy and pathophysiology . Neonatal patient assessment skills, including the ability to recognize and respond to adverse reactions and/or complications of the procedure. Knowledge and understanding of the patient's history and clinical condition. Knowledge and understanding of airway management. Ability to interpret monitored and measured blood gas variables and vital signs. Proper use, understanding, and mastery of emergency resuscitation equipment and procedures. Ability to evaluate and document outcome. Understanding and proper application of Universal Precautions.

MONITORING: 

MONITORING Variables to be monitored during surfactant administration ; Proper placement and position of delivery device. Ventilator settings. Reflux of surfactant into ETT. Position of patient ( ie , head direction). Chest-wall movement. Oxygen saturation by pulse oximetry . Heart rate, respirations, chest expansion, skin color, and vigor. Variables to be monitored after surfactant administration ; Invasive and noninvasive measurements of arterial blood gases. Chest radiograph. Ventilator settings. Pulmonary mechanics and volumes. Heart rate, respirations, chest expansion, skin color, and vigor. Breath sounds. Blood pressure.

FREQUENCY: 

FREQUENCY The frequency with which surfactant replacement is performed should depend upon; the clinical status of the patient. The indication for performing the procedure. Additional doses of surfactant, given at 6- to 24-hour intervals, may be indicated; In infants who experience increasing ventilator requirements whose conditions fail to improve after the initial dose.

INFECTION CONTROL: 

INFECTION CONTROL Universal Precautions should be implemented. Aseptic technique should be practiced. Appropriate Antibiotics should be started where applicable.

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T H A N K S