Sections

Workup

Laboratory Studies

Acid-base status

Ventilation-perfusion (V/Q) mismatch and perinatal stress are prevalent in meconium aspiration syndrome (MAS); therefore, assessment of the infant's acid-base status is crucial.

Metabolic acidosis from perinatal stress is complicated by respiratory acidosis from parenchymal disease and persistent pulmonary hypertension of the newborn (PPHN).

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 (CBC) count

Note the following:

In utero or perinatal blood loss, as well as infection, contributes to postnatal stress.
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.
Polycythemia may be present secondary to chronic fetal hypoxia; polycythemia is associated with decreased pulmonary blood flow and may exacerbate the hypoxia associated with MAS and PPHN.
There is little evidence that empiric antibiotic therapy after obtaining a blood culture is beneficial, except in the case of prolonged rupture of the membranes and maternal fever.

Fetal scalp blood lactate sampling has not been shown to reduce the risk of respiratory distress syndrome in infants with meconium-stained amniotic fluid.^[14]

Chest radiography

Chest radiography is essential in order to achieve the following:

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

See the images below.

Air trapping and hyperexpansion from airway obstruction.

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Acute atelectasis.

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Pneumomediastinum from gas trapping and air leak.

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Left pneumothorax with depressed diaphragm and minimal mediastinal shift because of noncompliant lungs.

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Diffuse chemical pneumonitis from constituents of meconium.

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Ultrasonography

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.

A prospective observational study of 117 newborns with MAS (and 100 controls) demonstrated that pulmonary ultrasonography may be a convenient, noninvasive, and accurate imaging modality for the diagnosis of MAS.^[15]The primary features of MAS noted on sonograms included the following^[15]:

Pulmonary consolidation with air bronchograms (all patients)
Pleural line anomalies and absence of the A-line (all patients)
Alveolar-interstitial syndrome or B-lines in nonconsolidated regions (all patients)
Atelectasis in severe MAS (16.2% of severe cases)
Pleural effusion (13.7% of patients)

Brain imaging studies

Later in the course of MAS, when the infant is stable and if the infant's neurologic examination is abnormal, imaging studies of the brain (eg, magnetic resonance imaging [MRI], computed tomography [CT] scanning, cranial ultrasonography) are indicated.

Treatment & Management

Singh BS, Clark RH, Powers RJ, Spitzer AR. Meconium aspiration syndrome remains a significant problem in the NICU: outcomes and treatment patterns in term neonates admitted for intensive care during a ten-year period. J Perinatol. 2009 Jul. 29(7):497-503. [QxMD MEDLINE Link].
Autilio C, Echaide M, Shankar-Aguilera S, et al. Surfactant injury in the early phase of severe meconium aspiration syndrome. Am J Respir Cell Mol Biol. 2020 Sep. 63(3):327-37. [QxMD MEDLINE Link]. [Full Text].
Terasaka D, Clark DA, Singh BN, Rokahr J. Free fatty acids of human meconium. Biol Neonate. 1986. 50(1):16-20. [QxMD MEDLINE Link].
Olicker AL, Raffay TM, Ryan RM. Neonatal respiratory distress secondary to meconium aspiration syndrome. Children (Basel). 2021 Mar 23. 8(3):715-21. [QxMD MEDLINE Link]. [Full Text].
Hermansen CL, Mahajan A. Newborn respiratory distress. Am Fam Physician. 2015 Dec 1. 92(11):994-1002. [QxMD MEDLINE Link].
Yoder BA, Kirsch EA, Barth WH, Gordon MC. Changing obstetric practices associated with decreasing incidence of meconium aspiration syndrome. Obstet Gynecol. 2002 May. 99(5 pt 1):731-9. [QxMD MEDLINE Link].
Balchin I, Whittaker JC, Lamont RF, Steer PJ. Maternal and fetal characteristics associated with meconium-stained amniotic fluid. Obstet Gynecol. 2011 Apr. 117(4):828-35. [QxMD MEDLINE Link].
Macfarlane PI, Heaf DP. Pulmonary function in children after neonatal meconium aspiration syndrome. Arch Dis Child. 1988 Apr. 63(4):368-72. [QxMD MEDLINE Link].
Ghidini A, Spong CY. Severe meconium aspiration syndrome is not caused by aspiration of meconium. Am J Obstet Gynecol. 2001 Oct. 185(4):931-8. [QxMD MEDLINE Link].
[Guideline] Wyckoff MH, Aziz K, Escobedo MB, et al. Part 13: Neonatal resuscitation: 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2015 Nov 3. 132(18 suppl 2):S543-60. [QxMD MEDLINE Link]. [Full Text].
American College of Obstetricians and Gynecologists. ACOG Committee opinion no. 689 summary: delivery of a newborn with meconium-stained amniotic fluid. Obstet Gynecol. 2017 Mar. 129(3):593-4. [QxMD MEDLINE Link].
American College of Obstetricians and Gynecologists. ACOG Committee opinion no. 689 summary: delivery of a newborn with meconium-stained amniotic fluid. American College of Obstetricians and Gynecologists. 2021. Available at https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/03/delivery-of-a-newborn-with-meconium-stained-amniotic-fluid. Accessed: June 20, 2023.
Nangia S, Pal MM, Saili A, Gupta U. Effect of intrapartum oropharyngeal (IP-OP) suction on meconium aspiration syndrome (MAS) in developing country: A RCT. Resuscitation. 2015 Dec. 97:83-7. [QxMD MEDLINE Link].
Boujenah J, Oliveira J, De La Hosseraye C, et al. Should fetal scalp blood sampling be performed in the case of meconium-stained amniotic fluid?. J Matern Fetal Neonatal Med. 2016 Dec. 29(23):3875-8. [QxMD MEDLINE Link].
Liu J, Cao HY, Fu W. Lung ultrasonography to diagnose meconium aspiration syndrome of the newborn. J Int Med Res. 2016 Dec. 44(6):1534-42. [QxMD MEDLINE Link]. [Full Text].
American College of Obstetricians and Gynecologists. ACOG Committee opinion no 579: definition of term pregnancy. Obstet Gynecol. 2013 Nov. 122(5):1139-40. [QxMD MEDLINE Link].
American College of Obstetricians and Gynecologists. ACOG Committee opinion no. 561: nonmedically indicated early-term deliveries. Obstet Gynecol. 2013 Apr. 121(4):911-5. [QxMD MEDLINE Link].
ACOG Committee Obstetric Practice. ACOG Committee opinion number 346, October 2006: amnioninfusion does not prevent meconium aspiration syndrome. Obstet Gynecol. 2006 Oct. 108(4):1053. [QxMD MEDLINE Link].
Velaphi S, Vidyasagar D. Intrapartum and postdelivery management of infants born to mothers with meconium-stained amniotic fluid: evidence-based recommendations. Clin Perinatol. 2006 Mar. 33(1):29-42, v-vi. [QxMD MEDLINE Link].
Hofmeyr GJ, Xu H. Amnioinfusion for meconium-stained liquor in labour. Cochrane Database Syst Rev. 2010 Jan 20. CD000014. [QxMD MEDLINE Link].
Fraser WD, Hofmeyr J, Lede R, et al, for the Amnioinfusion Trial Group. Amnioinfusion for the prevention of the meconium aspiration syndrome. N Engl J Med. 2005 Sep 1. 353(9):909-17. [QxMD MEDLINE Link]. [Full Text].
Davis JD, Sanchez-Ramos L, McKinney JA, Lin L, Kaunitz AM. Intrapartum amnioinfusion reduces meconium aspiration syndrome and improves neonatal outcomes in patients with meconium-stained fluid: a systematic review and meta-analysis. Am J Obstet Gynecol. 2023 May. 228(5S):S1179-S1191.e19. [QxMD MEDLINE Link]. [Full Text].
Committee on Obstetric Practice, American College of Obstetricians and Gynecologists. ACOG Committee opinion no. 379: management of delivery of a newborn with meconium-stained amniotic fluid. Obstet Gynecol. 2007 Sep. 110(3):739. [QxMD MEDLINE Link].
Vain NE, Szyld EG, Prudent LM, Wiswell TE, Aguilar AM, Vivas NI. Oropharyngeal and nasopharyngeal suctioning of meconium-stained neonates before delivery of their shoulders: multicentre, randomised controlled trial. Lancet. 2004 Aug 14-20. 364(9434):597-602. [QxMD MEDLINE Link].
Chettri S, Bhat BV, Adhisivam B. Current concepts in the management of meconium aspiration syndrome. Indian J Pediatr. 2016 Oct. 83(10):1125-30. [QxMD MEDLINE Link].
Wiswell TE, Knight GR, Finer NN, et al. A multicenter, randomized, controlled trial comparing Surfaxin (Lucinactant) lavage with standard care for treatment of meconium aspiration syndrome. Pediatrics. 2002 Jun. 109(6):1081-7. [QxMD MEDLINE Link].
Dargaville PA, Mills JF. Surfactant therapy for meconium aspiration syndrome: current status. Drugs. 2005. 65(18):2569-91. [QxMD MEDLINE Link].
Dargaville PA. Innovation in surfactant therapy I: surfactant lavage and surfactant administration by fluid bolus using minimally invasive techniques. Neonatology. 2012. 101(4):326-36. [QxMD MEDLINE Link].
El Shahed AI, Dargaville PA, Ohlsson A, Soll R. Surfactant for meconium aspiration syndrome in term and late preterm infants. Cochrane Database Syst Rev. 2014 Dec 14. CD002054. [QxMD MEDLINE Link].
Collins MP, Lorenz JM, Jetton JR, Paneth N. Hypocapnia and other ventilation-related risk factors for cerebral palsy in low birth weight infants. Pediatr Res. 2001 Dec. 50(6):712-9. [QxMD MEDLINE Link].
Abman SH, Kinsella JP. Inhaled nitric oxide therapy for pulmonary disease in pediatrics. Curr Opin Pediatr. 1998 Jun. 10(3):236-42. [QxMD MEDLINE Link].
Ward M, Sinn J. Steroid therapy for meconium aspiration syndrome in newborn infants. Cochrane Database Syst Rev. 2003. CD003485. [QxMD MEDLINE Link].
von Bahr V, Hultman J, Eksborg S, et al. Long-term survival and causes of late death in children treated with extracorporeal membrane oxygenation. Pediatr Crit Care Med. 2017 Mar. 18(3):272-80. [QxMD MEDLINE Link].
Bembea MM, Felling RJ, Caprarola SD, et al. Neurologic outcomes in a two-center cohort of neonatal and pediatric patients supported on extracorporeal membrane oxygenation. ASAIO J. 2020 Jan. 66(1):79-88. [QxMD MEDLINE Link]. [Full Text].
Sarkar S, Hussain N, Herson V. Fibrin glue for persistent pneumothorax in neonates. J Perinatol. 2003 Jan. 23(1):82-4. [QxMD MEDLINE Link].
El Shahed AI, Dargaville P, Ohlsson A, Soll RF. Surfactant for meconium aspiration syndrome in full term/near term infants. Cochrane Database Syst Rev. 2007 Jul 18. 2:CD002054. [QxMD MEDLINE Link]. [Full Text].
[Guideline] American Heart Association, American Academy of Pediatrics. 2005 American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) of pediatric and neonatal patients: neonatal resuscitation guidelines. Pediatrics. 2006 May. 117(5):e1029-38. [QxMD MEDLINE Link].
Dargaville PA, Copnell B, and the Australian and New Zealand Neonatal Network. The epidemiology of meconium aspiration syndrome: incidence, risk factors, therapies, and outcome. Pediatrics. 2006 May. 117(5):1712-21. [QxMD MEDLINE Link].
Kugelman A, Gangitano E, Taschuk R, et al. Extracorporeal membrane oxygenation in infants with meconium aspiration syndrome: a decade of experience with venovenous ECMO. J Pediatr Surg. 2005 Jul. 40(7):1082-9. [QxMD MEDLINE Link].
Boet A, Brat R, Aguilera SS, Tissieres P, De Luca D. Surfactant from neonatal to pediatric ICU: bench and bedside evidence. Minerva Anestesiol. 2014 Dec. 80(12):1345-56. [QxMD MEDLINE Link].

Media Gallery

Air trapping and hyperexpansion from airway obstruction.
Acute atelectasis.
Pneumomediastinum from gas trapping and air leak.
Left pneumothorax with depressed diaphragm and minimal mediastinal shift because of noncompliant lungs.
Diffuse chemical pneumonitis from constituents of meconium.

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Author

Gina M Geis, MD Attending Neonatologist, Associate Director, Neonatal-Perinatal Medicine Fellowship Program, Albany Medical Center; Assistant Professor, Department of Pediatrics, Albany Medical College

Gina M Geis, MD is a member of the following medical societies: American Academy of Pediatrics, American Society for Bioethics and Humanities, Capital District Pediatric Society

Disclosure: Nothing to disclose.

Coauthor(s)

David A Clark, MD Professor and Martha Lepow Chairman of Pediatrics, Professor of Obstetrics and Gynecology, Albany Medical College; Director, Children's Hospital at Albany Medical Center

David A Clark, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American College of Nutrition, American Forestry Association, American Pediatric Society, Capital District Pediatric Society, Christian Medical and Dental Associations, European Society for Paediatric Research, Eastern Society for Pediatric Research, Floyd W Denny Pediatric Alumni Society, Medical Society of the State of New York, New York Academy of Sciences, Society for Pediatric Research

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Brian S Carter, MD, FAAP Professor of Pediatrics, University of Missouri-Kansas City School of Medicine; Attending Physician, Division of Neonatology, Children's Mercy Hospital and Clinics; Faculty, Children's Mercy Bioethics Center

Brian S Carter, MD, FAAP is a member of the following medical societies: Alpha Omega Alpha, American Academy of Hospice and Palliative Medicine, American Academy of Pediatrics, American Pediatric Society, American Society for Bioethics and Humanities, American Society of Law, Medicine & Ethics, Society for Pediatric Research, National Hospice and Palliative Care Organization

Disclosure: Nothing to disclose.

Chief Editor

Dharmendra J Nimavat, MD, FAAP Associate Professor of Clinical Pediatrics, Department of Pediatrics, Division of Neonatology, Southern Illinois University School of Medicine; Staff Neonatologist, Clinical Director, NICU Regional Perinatal Center, HSHS St John's Children's Hospital

Dharmendra J Nimavat, MD, FAAP is a member of the following medical societies: American Academy of Pediatrics, American Association of Physicians of Indian Origin

Disclosure: Nothing to disclose.

Additional Contributors

Ted Rosenkrantz, MD Professor, Departments of Pediatrics and Obstetrics/Gynecology, Division of Neonatal-Perinatal Medicine, University of Connecticut School of Medicine

Ted Rosenkrantz, MD is a member of the following medical societies: American Academy of Pediatrics, American Pediatric Society, Eastern Society for Pediatric Research, American Medical Association, Connecticut State Medical Society, Society for Pediatric Research

Disclosure: Nothing to disclose.

Meconium Aspiration Syndrome Workup

Laboratory Studies

Acid-base status

Serum electrolytes

Complete blood cell (CBC) count

Imaging Studies

Chest radiography

Ultrasonography

Brain imaging studies

Meconium Aspiration Syndrome Workup

Laboratory Studies

Acid-base status

Serum electrolytes

Complete blood cell (CBC) count

Imaging Studies

Chest radiography

Ultrasonography

Brain imaging studies

References

Tables

Contributor Information and Disclosures

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