Sindroma Aspirasi Mekonium

Meconium Aspiration Syndrome( MAS )

Bambang MulyawanFK-UMM

Pendahuluan MAS merupakan masalah kegawatan yg sering dijumpai di ruang bersalin ( hipoksia intrauterine aspirasi pneumoni BBL )Biasanya pd bayi cukup bulan dan lebih bulan ( : Kecil untuk Masa Kehamilan / KMK )Waspada : jika BBL lahir dg cairan ketuban campur mekonium dg gejala RDS

Patogenesis dan patofisiologi Stress intrauterin mekonium in-utero ke dlm cairan ketuban, terhisap janin ketika inspirasi o.k hipoksi dan stimulasi vagal fetal distres / sebelum persa-linanMekanisme keluarnya mekonium in-utero masih belum jelas

Patogenesis dan patofisiologi ( lanj.)BBL dg cairan ketuban mekonial asfiksia antepartum atau intrapartum obstruksi jalan nafas, turunnya kapasitas paru, pe> expiratory large airway resistancxeObstruksi total : atelektasis. Partial : trapping udara dan hiperekspansi alveolarMekonium pd alveolar me< fungsi surfaktan kolaps RDS

Patogen . . . . . ( lanj. )Hipoksia intrauterin aspirasi mekonium obstruksi mekanik / keradangan kimiawi air trapping / atelektasis ventilasi tidak seimbang / intrapulmonal shunting kebocoran udara hipoksemia asidosis sirkulasi fetal persistent

*SINDROM ASPIRASI MEKONIUM (SAM)Hipoksia janinMekonium keluar & janin gaspingCairan amnion yang terkontaminasi mekonium terhirup ke larings dan trakheaMekonium masuk saluran napas lebih kecil dan alveolus Kerusakan paru Pembersihan sal. napas tidak adekuat

*Kerusakan paruMekonium mengandung enzim merusak epitel bronkus, bronkiolus dan alveolusMekonium menyumbat sal. napas secara total/parsial beberapa bagian paru kolaps, bagian paru lain hiperinflasi

What Is Meconium?Odorless, thick, blackish green materialFirst seen during the third month of gestationAccumulation of desquamated cells from GI tract, skin, lanugo, fatty material from the vernix, amniotic fluid

Manifestasi klinisBervariasi : tergantung keparahan serangan hipoksik dan jumlah viskositas mekonium teraspirasiSering pada gestasi post matur : warna meko. pd kuku, rambut, tali pusatGejala RDS ( takipnea, NCH, retraksi interkostal, diameter AP dada >, sianosisPada gejala MAS lambat : distres nafas awal ringan. Semakin parah bbrp jam : atelektasis dan pneumonitis kimiaAuskultasi : vesikular lemag, ronki/rales, wheezing/mengi

Pemeriksaan radiologisFoto polos dada : infiltrat kasar menyebar pd kedua lap.paru, dapat disertai pneumotoraks, atelektasis, emfisema

Chest X-RayHyperinflationCoarse, patchy densities representing scattered areas of atelectasis and consolidation mixed with air trapping

Faktor predisposisiInsufisiensi plasenta, hipertensi, oligohidramnion, ibu kecanduan ( rokok, kokain), infeksi (chorio-amnionitis) hipoksia, manajemen jalan nafas tidak adekuat, defisiensi surfaktan, hipertensi pulmonal

Risk Factors for Meconium PassagePostterm pregnancyPreeclampsia-eclampsiaMaternal hypertensionMaternal diabetes mellitusAbnormal fetal heart rateIUGRAbnormal biophysical profileOligohydramniosMaternal heavy smoking

Infant ActiveInfant DepressedIntrapartum suctioning of mouth, nose, pharynxIntubate and suction trachea Other resuscitation as indicatedObserve

Langkah diagnostikRiwayat : PJT ( pertumbuhan janin terhambat ), kesulitan persalinan / gawat janin, persalinan dg air ketuban mekonial, asfiksia beratPemerksaan fisik : cair ketuban mekonial/ bayi diliputi mekonium, tl pusat/kulit bayi warna hijau, asfiksia berat bbrp jam gangguan nafas/RDS, td bayi lebih bulanFoto toraks : AP dan LateralLaboratorium: Hb, Ht, darah tepi, kulturAnalisa Gas Darah : hipoksemia, asidemia : asidosis metabolik, respiratorik,/kombinasi

*Diagnosis Cukup/lebih bulan, jarang sekali kurang bulanCairan amnion terkontaminasi mekoniumMekonium tampak/dapat dihisap dari saluran napas atas (bantuan laringoskop)Kulit bayi diwarnai mekoniumSesak napasFoto toraks : hiperinflasi paru disertai banyak daerah paru yang kolaps

*Pencegahan Pembersihan saluran napas atas sebelum bayi bernapas saat lahirPenghisapan saluran napas sebelum bahu dilahirkan

Penghisapan saluran napas (larings dan trakea) secara langsung dengan bantuan laringoskop

penatalaksanaanPrevensi slm periode prenatal, antenatal, tindaka tepat slm intrapartumDiagram Alur Resusitasi Neonatus

Pengobatan / terapiSuportif : oksigen, suhu lingkungan, perawatan pernafasan, kadar gas darah arteri, terapi surfaktan, ventilasi mekanik, cairan infus glukosa 10%Antibiotik spektrum luasTindakan bedah :pd pneumotoraks, pneumomediastinum, empisema subkutan : pungsi toraks, drainase

*Perjalanan PenyakitSAM : sesak napas sejak lahirSAM ringan : membaik secara bertahap dalam beberapa hari beberapa minggu Memburuk secara progresif tidak tertolong Tertolong kerusakan paru perlu waktu lama untuk sembuh sempurna SAM berat

*Komplikasi Pneumotoraks / pneumomediastinumKerusakan akibat hipoksia pada organ lain

Pemantauan/MonitoringTumbuh kembang pd bayi yg selamat, hidup tanpa komplikasi (survival intact) baikPada bayi dg komplikasi hipoksi serebri, gagal ginjal, efek tosik O2, epilepsi, palsi serebral gangguan tumbuh kembang

PathogenesisMeconium stained amniotic fluid (MSAF) occurs in 10-25% of all deliveriesMeconium aspiration syndrome (MAS) occurs in 2-5% of infants born through MSAF

PathogenesisRisk increases with gestational ageBefore 37 weeks the risk of MSAF is 2%After 44 weeks the risk of MSAF is 44%

PathogenesisCause of MSAF is unclearStudies have not shown that it is synonymous with fetal asphyxiaMSAF with fetal bradycardia does correlate with increased perinatal morbidity

PathogenesisNormal fetuses have respiratory movements in uteroIf a fetus is hypoxemic, respirations briefly stopWith prolonged hypoxia, apnea turns into gasping

PathogenesisGasping meconium stained fluid can lead to mechanical obstruction of the airwaysYeomans et al showed that cord arterial pH is lower in infants with meconium in their trachea at delivery which suggests in utero stress

PathogenesisIf meconium is not suctioned out of the airway at delivery, it can migrate to the periphery of the lungSmall airway obstruction produces patchy atelectasis and hyperinflationThis leads to a chemical pneumonitis and interstitial edemaAlveoli are infiltrated with debris, neutrophils, and necrosed epithelial cells

PathogenesisPulmonary vascular resistance can be increased by increased vascular smooth muscle in the normally nonmuscularized intra-acinar arteriolesPulmonary hypertension frequently complicates MAS

PathogenesisEndogenous surfactant can be inactivated by meconium and the chemical pneumonitis This may worsen the severity of the illness

Clinical ManifestationsOften postmatureMeconium staining of skin and nailsDistressedBarrel chest from hyperinflationCrackles in lungs

Clinical ManifestationsPneumothorax is a common complicationSymptoms progress over 12 to 24 hours as the meconium migratesPhagocytes remove the meconium which takes days to weeks

Delivery Room TherapyWiswell and his colleagues performed a multicenter study on delivery room management of the apparently vigorous meconium stained neonateRoutine suctioning of the trachea no better than expectant management

Therapy: Wiswell Cont.Oropharyngeal suctioning with a bulb suction before the delivery of an infants shoulders is still recommendedAmnioinfusion did not help prevent MASNRP recommends tracheal suction of the nonvigorous infant born through meconium

TreatmentOxygenMechanical ventilation if necessaryKeep in mind that PPHN may be a component and treat appropriatelyiNOECMO

TreatmentSurfactantCochran review showed it may reduce the severity of respiratory illness and decrease need for ECMOAntibioticsControversial: no studies have shown a role of infection in MASDifficult to distinguish infectious pneumonia from MAS

TreatmentSteroidsProlongs the course of MAS by increasing the time to wean to room air

OutcomeInfants with MAS do very wellOverall mortality of infants with MSAF is 0.15%Infants with MAS on ECMO have a mortality range of 0-5% depending on the institution