Meconium Aspiration Syndrome Nursing Management

Description

Meconium is the first intestinal discharge from newborns, a viscous, dark-green substance composed of intestinal epithelial cells, lanugo, mucus, and intestinal secretions.

• Meconium aspiration syndrome (MAS) is the aspiration of stained amniotic fluid, which can occur before, during, or immediately after birth.
• Meconium is sterile and does not contain bacteria, which is the primary factor that differentiates it from a stool.
• As noted above, meconium-stained amniotic fluid may be aspirated before or during labor and delivery; because meconium is rarely found in the amniotic fluid prior to 34 weeks’ gestation, meconium aspiration primarily affects infants born at term and post-term.

Pathophysiology

In utero, meconium passage results from neural stimulation of a maturing gastrointestinal (GI) tract, usually due to fetal hypoxic stress.

• As the fetus approaches term, the GI tract matures, and vagal stimulation from the head or spinal cord compression may cause peristalsis and relaxation of the rectal sphincter, leading to meconium passage.
• Meconium directly alters the amniotic fluid, reducing antibacterial activity and subsequently increasing the risk of perinatal bacterial infection.
• In addition, meconium is irritating to fetal skin, thus increasing the incidence of erythema toxicum.
• However, the most severe complication of meconium passage in utero is perinatal aspiration of stained amniotic fluid (before, during, or immediately after birth)—ie, meconium aspiration syndrome (MAS).
• Aspiration of meconium-stained amniotic fluid may occur if the fetus is in distress, leading to a gasping breathing pattern.
• This aspiration induces hypoxia via four major pulmonary effects: airway obstruction, surfactant dysfunction, chemical pneumonitis, and pulmonary hypertension.

Statistics and Incidences

The occurrence of meconium aspiration syndrome in the United States and worldwide are as follows:

• Historically, approximately 10% of newborns born through meconium-stained amniotic fluid developed meconium aspiration syndrome (MAS).
• However, changes in obstetric and neonatal practices appear to be decreasing its incidence; MAS was the admission diagnosis for 1.8% of term neonates in one large retrospective study from 1997-2007.
• In developing countries with less availability of prenatal care and where home births are common, the incidence of MAS is thought to be higher and is associated with a greater mortality rate.
• MAS is exclusively a disease of newborns, especially those delivered at or beyond the mother‘s estimated due date; MAS affects both sexes equally.
• A study of 499,096 singleton live births in London, England, reported the rates of meconium-stained amniotic fluid varied by ethnicity: It was 22.6% in the black population, 16.8% in South Asian groups, and 15.7% in the white population.

Causes

Causes of meconium aspiration syndrome are:

• Placental insufficiency. When a mother has placental insufficiency, there is a lack of adequate blood flow to the baby, which can cause fetal distress, leading to the untimely passage of meconium.
• Preeclampsia. When the placenta does not carry adequate oxygen and nutrition for the fetus due to maternal underperfusion such as preeclampsia, the placental villi show increased syncytial knots, villous agglutination, intervillous fibrin, and distal villous hypoplasia, while maternal vessels in the deciduadisclose atherosis or mural hypertrophy of the arterioles.
• Maternal infection/chorioamnionitis. When the placental membranes are ruptured and amniotic fluid infection occurs, the placenta shows acute chorioamnionitis (as the maternal inflammatory response) and funisitis (as the fetal inflammatory response).
• Fetal hypoxia. Fetal hypoxia leads to passage of meconium from neural stimulation of a maturing gastrointestinal system.

Clinical Manifestations

The signs and symptoms of meconium aspiration syndrome include:

• Severe respiratory distress. Severe respiratory distress may be present; symptoms include cyanosis, end-expiratory grunting, nasal flaring, intercostal retractions, tachypnea, barrel chest due to the presence of air trapping, and in some cases, auscultated rales and rhonchi.
• Staining of the fingernails. Yellow-green staining of fingernails, umbilical cord, and skin may be also observed.
• Green urine. Green urine may be noted in newborns with MAS less than 24 hours after birth; meconium pigments can be absorbed by the lung and can be excreted in urine.

Assessment and Diagnostic Findings

Work-up for a newborn with meconium aspiration syndrome include the following:

• Acid-base status. Measurement of arterial blood gas (ABG) pH, partial pressure of carbon dioxide (pCO2), and partial pressure of oxygen (pO2), as well as continuous monitoring of oxygenation by pulse oximetry, are necessary for appropriate management; the calculation of an oxygenation index (OI) can be helpful when considering advanced treatment modalities, such as extracorporeal membrane oxygenation (ECMO).
• Serum electrolytes. Obtain sodium, potassium, and calcium concentrations at 24 hours of life in infants with MAS, because syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and acute renal failure are frequent complications of perinatal stress.
• Complete blood cell count. Hemoglobin and hematocrit levels must be sufficient to ensure adequate oxygen-carrying capacity; thrombocytopenia increases the risk for neonatal hemorrhage; neutropenia or neutrophilia with left shift of the differential may indicate perinatal bacterial infection.
• Chest radiography. Chest radiography is essential in order to confirm the diagnosis of meconium aspiration syndrome (MAS) and determine the extent of the intrathoracic pathology; identify areas of atelectasis and air leak syndromes; ensure appropriate positioning of the endotracheal tube and umbilical catheters.
• Echocardiography. Echocardiography is necessary to ensure normal cardiac structure and for assessment of cardiac function, as well as to determine the severity of pulmonary hypertension and right-to-left shunting.

Medical Management

The American College of Obstetricians and Gynecologists (ACOG) continues to provide guidance regarding the appropriate indications for delivery to prevent neonatal complications of a prolonged pregnancy, as well as for avoiding the unnecessary delivery of a preterm baby.

• Cardiac exam. In patients with meconium aspiration syndrome (MAS), a thorough cardiac examination and echocardiography are necessary to evaluate for congenital heart disease and persistent pulmonary hypertension of the newborn (PPHN).
• Rooming-in. If the baby is vigorous (defined as having a normal respiratory effort and normal muscle tone), the baby may stay with the mother to receive the initial steps of newborn care; a bulb syringe can be used to gently clear secretions from the nose and mouth.
• Placing in a radiant warmer. If the baby is not vigorous (defined as having a depressed respiratory effort or poor muscle tone), place the baby on a radiant warmer, clear the secretions with a bulb syringe, and proceed with the normal steps of newborn resuscitation (ie, warming, repositioning the head, drying, and stimulating).
• Minimize handling. Minimal handling is essential because these infants are easily agitated; agitation can increase pulmonary hypertension and right-to-left shunting, leading to additional hypoxia and acidosis; sedation may be necessary to reduce agitation.
• Insertion of umbilical artery catheter. An umbilical artery catheter should be inserted to monitor blood pH and blood gases without agitating the infant.
• Respiratory care. Continue respiratory care includes oxygen therapy via hood or positive pressure, and it is crucial in maintaining adequate arterial oxygenation; mechanical ventilation is required by approximately 30% of infants with MAS; make concerted efforts to minimize the mean airway pressure and to use as short an inspiratory time as possible; oxygen saturation should be maintained at 90-95%.
• Surfactant therapy. Surfactant therapy is commonly used to replace displaced or inactivated surfactant and as a detergent to remove meconium; although surfactant use does not appear to affect mortality rates, it may reduce the severity of disease, progression to extracorporeal membrane oxygenation (ECMO) utilization, and decrease the length of hospital stay.
• IV fluids. Intravenous fluid therapy begins with adequate dextrose infusion to prevent hypoglycemia; intravenous fluids should be provided at mildly restricted rates (60-70 mL/kg/day).
• Diet. Progressively add electrolytes, protein, lipids, and vitamins to ensure adequate nutrition and to prevent deficiencies of essential amino acids and essential fatty acids.

Pharmacologic Management

In addition to the treatments discussed earlier and the medications listed below, surfactant replacement therapy is frequently used in infants with meconium aspiration syndrome (MAS).

• Respiratory gases. Inhaled nitric oxide (NO) has the direct effect of pulmonary vasodilatation without the adverse effect of systemic hypotension; it is approved for use if concomitant hypoxemic respiratory failure occurs.
• Systemic vasoconstrictors. These agents are used to prevent right-to-left shunting by raising systemic pressure above pulmonary pressure; systemic vasoconstrictors include dopamine, dobutamine, and epinephrine; dopamine is the most commonly used.
• Sedatives. These agents maximize the efficiency of mechanical ventilation, minimize oxygen consumption, and treat the discomfort of invasive therapies.
• Neuromuscular blocking agents. These agents are used for skeletal muscle paralysis to maximize ventilation by improving oxygenation and ventilation; they are also used to reduce barotrauma and minimize oxygen consumption.

Nursing Management

Nursing care of an infant with meconium aspiration syndrome include the following:

Nursing Assessment

Assessment of an infant with meconium aspiration syndrome include:

• History. The presence of meconium in amniotic fluid is required to cause meconium aspiration syndrome (MAS), but not all neonates with meconium-stained fluid develop this condition.
• Physical exam. The diagnosis of MAS requires the presence of meconium-stained amniotic fluid or neonatal respiratory distress, as well as characteristic radiographic abnormalities.

Nursing Diagnosis

Based on the assessment data, the major nursing diagnoses for meconium aspiration syndrome are:

• Hyperthermia related to inflammatory process/ hypermetabolic state as evidenced by an increase in body temperature, warm skin and tachycardia.
• Fluid volume deficit related to failure of regulatory mechanism.
• Ineffective tissue perfusion related to impaired transport of oxygen across alveolar and on capillary membrane.
• Interrupted breastfeeding related to neonate’s present illness as evidenced by separation of mother to infant.
• Risk for Impaired parent/neonates attachment related to neonates physical illness and hospitalization.

Nursing Care Planning and Goals

The major nursing care planning goals for patients with Meconium aspiration syndrome are:

• Patient will maintain normal core temperature as evidenced by vital signs within normal limits and normal WBC level.
• Patient will be able to maintain fluid volume at a functional level as evidenced by individually adequate urinary output with normal specific gravity, stable vital signs, moist mucous membranes, good skin turgor and prompt capillary refill and resolution of edema.
• Patient will be able to maintain fluid volume at a functional level as evidenced by individually adequate urinary output with normal specific gravity, stable vital signs, moist mucous membranes, good skin turgor and prompt capillary refill and resolution of edema.
• Patient will demonstrate increased perfusion as evidenced by warm and dry skin, strong peripheral pulses, normal vital signs, adequate urine output and absence of edema.
• The mother will identify and demonstrate techniques to sustain lactation until breastfeeding is initiated.
• The mother shall still be able to identify and demonstrate techniques to sustain lactation and identify techniques on how to provide the newborn with breast milk.
• The mother will identify and demonstrate techniques to enhance behavioral organization of the neonate
• After discharge, the parents will be able to have mutually satisfying interactions with their newborn.

Nursing Interventions

Nursing interventions for the infant are:

• Reduce body temperature. Provide TSB to help lower down the temperature; ensure that all equipment used for the infant is sterile, scrupulously clean; do not share equipment with other infants to prevent the spread of pathogens, and administer antipyretics as ordered.
• Improve fluid volume level. Monitor and record vital signs to note for alterations; provide oral care by moistening lips & skin care by providing daily bath; administer IV fluid replacement as ordered to replace fluid losses.
• Increase tissue perfusion. Note quality and strength of peripheral pulses; assess respiratory rate, depth, and quality; assess skin for changes in color, temperature, and moisture; elevate affected extremities with edema once in a while to lower oxygen demand.
• Improve frequency of breastfeeding. Demonstrate the use of manual piston-type breast pump.; review techniques for storage/use of expressed breast milk; provide privacy, calm surroundings when the mother breastfeeds; recommend for infant sucking on a regular basis, and encourage the mother to obtain adequate rest, maintain fluid and nutritional intake, and schedule breast pumping every 3 hours while awake.
• Improve infant-parent relationship. Educate parents regarding child growth and development, addressing parental perceptions; involve parents in activities with the newborn that they can accomplish successfully, and recognize and provide positive feedback for nurturing and protective parenting behaviors.

Evaluation

Goals are met as evidenced by:

• Patient maintained normal core temperature as evidenced by vital signs within normal limits and normal WBC level.
• Patient was able to maintain fluid volume at a functional level as evidenced by individually adequate urinary output with normal specific gravity, stable vital signs, moist mucous membranes, good skin turgor and prompt capillary refill and resolution of edema.
• Patient was able to maintain fluid volume at a functional level as evidenced by individually adequate urinary output with normal specific gravity, stable vital signs, moist mucous membranes, good skin turgor and prompt capillary refill and resolution of edema.
• Patient demonstrated increased perfusion as evidenced by warm and dry skin, strong peripheral pulses, normal vital signs, adequate urine output and absence of edema.
• The mother identified and demonstrated techniques to sustain lactation until breastfeeding is initiated.
• The mother was able to identify and demonstrate techniques to sustain lactation and identify techniques on how to provide the newborn with breast milk.
• The mother identified and demonstrated techniques to enhance behavioral organization of the neonate
• After discharge, the parents were able to have a mutually satisfying interaction with their newborn.

Documentation Guidelines

Documentation in an infant with meconium aspiration syndrome include:

• Individual findings, including factors affecting, interactions, nature of social exchanges, specifics of individual behavior.
• Intake and output.
• Signs of infection.
• Cultural and religious beliefs, and expectations.
• Plan of care.
• Teaching plan.
• Responses to interventions, teaching, and actions performed.
• Attainment or progress toward the desired outcome.

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