Treatment of aspiration syndrome in newborns

It is believed that aspiration of meconium can almost always be prevented if appropriate monitoring is carried out in the antenatal period, to accelerate the course of labor, and immediately to clean the trachea in the newborn. Doctors conducted a study of clinical-pathoanatomical features in the syndrome of meconium aspiration based on the analysis of 14 genera with the presence of meconium in waters where meconium aspiration syndrome caused neonatal mortality. In the study group, all women in labor were primiparous. Intranatally, 6 (42.8%) of the fetuses died, in all of these cases the delivery was completed by the imposition of cavitary obstetric forceps and a vacuum extractor. The remaining newborns at birth had an Apgar score of 5 or lower. Immediately after birth, all children were sucked off mucus from the upper respiratory tract, ventilators were used, soda, glucose, and ztimizole solutions were injected into the vein of the umbilical cord, and a session of hyperbaric oxygenation was administered.

Despite the ongoing resuscitation, 7 (50%) children died in the first day after delivery from massive aspiration of meconium, the rest - on the 2-4th day of severe aspiration pneumonia. The diagnosis of meconium aspiration was confirmed during autopsy. A typical pathoanatomical picture was the filling of the lumen of the bronchi with a large amount of mucus, elements of amniotic fluid, meconium. The alveoli in all cases were enlarged, in the lumen they were determined a large number of amniotic fluid, the particles of meconium. In three cases there was a rupture of the wall of the alveoli, extensive hemorrhage was found under the pleura.

When the meconium is thick, in the form of clumps, one should try to clear the nose and oropharynx from it even before the thorax comes out of the birth canal. Immediately after birth, if the meconium is thick or the Apgar score is lower than 6, endotracheal intubation should be undertaken to draw off the contents of the trachea prior to the initiation of artificial respiration. If these measures are not performed immediately after birth, the incidence of aspiration syndrome and mortality increase. This procedure is shown even in cases of absence of meconium in the oropharynx (as shown, 17% of newborns having meconium in the trachea, the latter in the oropharynx was not found). Suctioning of tracheal contents with repeated intubation or through a catheter should be repeated until the trachea is completely cleared. Additional procedure in the delivery room - removal of swallowed meconium from the stomach - prevents repeated aspiration.

The newborn should be placed in a block of intensive observation. Continuous monitoring of pulse and respiration rate is important. To confirm the diagnosis and exclude pneumothorax, an X-ray examination is performed; it is repeated if the clinical picture deteriorates. Every newborn who needs a 30% air-oxygen mixture to preserve the pink color of the skin, it is advisable to catheterize any artery to constantly monitor the composition of the blood gases. Antibiotics of a wide spectrum of action are recommended, since the cause of hypoxia of the fetus and the release of meconium into the water may be bacterial sepsis. In a number of cases, pneumonia can not be distinguished from meconium aspiration syndrome, and even if meconium is sterile, its presence promotes bacterial growth. There is no evidence of a positive effect of steroids in this syndrome. To remove meconium from the lungs, physiotherapy and postural drainage can be used.

Approximately 50% of newborns with meconium aspiration develop respiratory failure. Artificial ventilation is shown at Ra below 80 mm Hg. Art. On 100% oxygen, Race, over 60 mm Hg. Art. Or apnea. Recommended parameters of artificial ventilation: respiratory rate 30-60 / min; inspiratory pressure 25-30 cm of water. P. Positive end-expiratory pressure (PEEP) 0-2 cm of water. P. The ratio between inspiration and expiration is from 1: 2 to 1: 4.

At high risk of hypoxic pulmonary vasoconstriction and low probability of retinopathy in a mature newborn, Ra should be maintained at the upper limit, ie 80-100 mm Hg. Art. To reduce Ra, the rapidity of breathing is preferable to increasing the tidal volume by creating a high peak pressure.

A high level of PEEP increases the risk of a decrease in venous return to the heart and, consequently, cardiac output, a decrease in lung elongation (which can lead to hypercapnia) and the formation of "air traps" (leading to rupture of the alveoli). However, if Ra remains below 60 mm Hg. Despite the artificial ventilation of the lungs with pure oxygen, one can try to improve blood oxygenation by increasing PEEP up to 6 cm of water. Art. This method should be carried out under close supervision because of possible complications. PEEP should be reduced if systemic hypotension, hypercapnia or air leakage from the lungs occur. Oxygenation improves if artificial ventilation is combined with muscle relaxation. This method is especially recommended if an X-ray examination reveals interstitial emphysema of the lungs, the child is not "synchronous" with the apparatus and the PEEP needs to be increased. Deterioration in the process of such treatment is possible due to the development of pneumothorax or clogging of the endotracheal tube with meconium. The most likely cause of persistent or increasing hypoxemia may be considered persistent pulmonary hypertension.

In conclusion, it should be noted that, according to the literary and our data, lethality in the meconium aspiration syndrome is 24-28%; in those cases when artificial ventilation was required, the lethality reached 36-53%.

If immediately after birth, before the first breath, the nasopharynx was cleared or the contents of the trachea were exhausted, no death was recorded.

The final prognosis depends not so much on developing lung disease as on perinatal asphyxia. No specific chronic pulmonary dysfunction is described.