Severe Meconium Aspiration Syndrome Research Articles

Treatment of severe meconium aspiration syndrome with porcine surfactant: A multicentre, randomized, controlled trial

Treatment of severe meconium aspiration syndrome with porcine surfactant: A multicentre, randomized, controlled trial

An international randomized controlled trial of amnioinfusion for thickly meconium stained amniotic fluid

To determine if amnioinfusion (AI) for thickly meconium stained amniotic fluid reduces (1) perinatal death and/or moderate to severe meconium aspiration syndrome (primary outcome measure), (2) cesarean section, (3) other indicators of serious neonatal and maternal morbidity. In 56 centres in 13 countries, 1998 laboring women at ≥36 weeks gestation with thickly meconium stained liquor were stratified according to the presence or absence of variable fetal heart rate decelerations and randomized either to standard care or to AI, consisting of a transcervical bolus of 800 mL saline over 40 minutes, followed by infusion of 2 mL/minute to a maximum of 1500 mL. The composite primary outcome measure included perinatal death and/or severe or moderate meconium aspiration syndrome (MAS) based on clinical respiratory distress (severe: requiring mechanical ventilation; moderate: requiring oxygen supplementation at a FiO2 ≥ 40% or of ≥48 hours duration) as blindly adjudicated by a group of 3 neonatologists. Perinatal death and/or moderate or severe MAS occurred in 44 (4.5%) babies in the amnioinfusion group and 34 (3.4%) babies in the control group (RR = 1.3, 95% CI = 0.8-2.0). There was a trend toward more frequent cesarean delivery in the AI group (32% vs 29%; RR = 1.1; 95% CI 1.0-1.3). The distribution of other indicators of severe neonatal morbidity including arterial cord pH < 7.05 and severe maternal morbidity were similar in the two treatment groups. We found no evidence of heterogeneity of treatment effect, either across stratum as defined above, or across centres. For women in labor with thickly meconium stained amniotic fluid, amnioinfusion does not reduce the risk of meconium aspiration syndrome, cesarean delivery, or other major indicators of maternal or neonatal morbidity.

246 A Randomized, Controlled Multicenter Trial Of Porcine Surfactant® For Treatment Of Severe Meconium Aspiration Syndrome

Background and objective: Despite improved perinatal monitoring and respiratory care, severe meconium aspiration syndrome (MAS) remains a life threatening respiratory disorder in early postnatal period. Pathogenesis and pathophysiology of MAS involves surfactant dysfunction due to inactivation by meconium at alveolar spaces. There has been no report about efficacy of Curosurf in MAS although a retrospective study revealed certain benefits. We hypothesized that in severe MAS, meconium-induced lung injury and impaired gas exchange may be altered by exogenous surfactant, and conducted this randomized. Controlled, multicenter study. Subjects and methods: Sixty-one term infants with severe MAS within 36 hours after birth were enrolled in this trial in nineteen neonatal intensive care services. The infants in the treatment group (n=31) received an initial dose of Curosurf at 200 mg/kg body weight, and repeated doses were given in 200, 100 and 100 mg/kg if a/A of the infant remained <0.20 at 6–12 hours after the previous dose. The primary evaluated parameters were oxygen requirement, ventilator settings, and incidence of complications. Results: The baseline demographic characteristics of the two groups were similar. There was a trend in favour of Curosurf for a more rapid improvement in blood oxygenation (Figure). The mean oxygenation index (OI) in the Curosurf group was significantly lower than the baseline value starting from the assessment at 1 hour. The number of infants with OI <10 in the Curosurf group was numerically higher than that in the control group (p<0.05 at the assessment of 24 hours post-administration). The a/A ratio at 24 hours was increased >100% compared to baseline in 24/29 (83%) infants treated with Curosurf and in 12/25 (48%) infants in the control group (p<0.05). Other secondary efficacy variables: reduction of MAP by ≥ 2 cm H20 at 24 and 72 hours, duration of mechanical ventilation, cumulative exposure to oxygen, did not show significant differences between groups. The survival rate was 30/31 and 27/30 in the Curosurf and control group, respectively. The incidence of complications did not differ between groups. Conclusion: Surfactant replacement therapy improved oxygenation and did not increase complications in the study subjects, suggesting that surfactant is effective and safe for treatment of severe MAS in term infants.

90 Surfactant Lung Lavage and Inhaled Nitric Oxide in The Treatment of Meconium Aspiration Syndrome 2- Influence on Duration of Mechanical Ventilation, Inhalation of Nitric Oxide, Hospitalization, and Complications

The most severe clinical problem which coexist with the meconium aspiration syndrome/MAS/is persistent pulmonary hypertension/PPHN/.The aim of our study was to evaluate the efficacy of treatment of MAS for selected clinical parameters. The designed therapeutic approach consisted of surfactant lung lavage/SLL/and surfactant instillation together with Nitric Oxide inhalation/iNO/. The study population was randomized into two groups: group A/n= 7/treated with SLL, surfactant instillation and iNO, and group B/n= 6/treated with surfactant instillation and iNO. Criteria for inclusion: maturity >35 weeks of gestation, time after delivery < 24hours, presence of fluid containing meconium below vocal cords, respiratory insufficiency demanding mechanical ventilation/Fi0240%/, radiological changes, and echocardiographic features of pulmonary hypertension.Method: SLL was performed with natural surfactant solution (Survanta, Ross Abbott Laboratories) in concentration of 5mg of phospholipids/1 ml 0,9% NaCl, a dose of 15ml of solution per 1 kg. A dose of 100 mg of Surfactant per 1 kg was applied. The initial NO dose was 20 ppm. The parameters analyzed: duration of IMV, duration of iNO, duration of hospitalization, air leaks and deaths.Results: (mean value ± b SD). Duration of IMV: GROUP A- 6,6± b 2,5days vs. GROUP B- 7,3± b 1,7days (NS). Duration of iNO: GROUP A- 2,9 ± b1,5days vs. GROUP B- 3,5 ± b1,3days (NS). Duration of hospitalization: GROUP A-16,4 ± b5,4 days vs. GROUP B- 19, ± b2,9 days (NS). Air leaks: GROUP A- 0 vs. GROUP B- 2 (NS). Deaths: GROUP A- 0; GROUP B- 2 (NS).Conclusions: The associated treatment of SLL with natural surfactant solution together with iNO in the therapy of severe meconium aspiration syndrome with persistent pulmonary hypertension does not have a significant influence on the reduction of duration of IMV, iNO and the hospitalization time and on the reduction of occurrence of complications and deaths.

Pulmonary function after surfactant lung lavage followed by surfactant administration in infants with severe meconium aspiration syndrome

The effect of surfactant lung lavage (SLL) on pulmonary function was examined in neonates with severe form of meconium aspiration syndrome (MAS) (mean +/- standard deviation: birth weight, 3178.1 +/- 237.6 g; gestational age, 37.7 +/- 1.8 weeks). The infants were on mechanical ventilation and were subjected to SLL with Survanta. Dynamic compliance (Cdyn), airway resistance (Raw) and mean airway pressure (MAP) were obtained with use of the pneumotachometric method. Measurements of Cdyn, Raw, MAP and time constant (Tc) were compared in the study and control groups and between the groups before SLL and 24 and 48 h after SLL. A significant increase in Cdyn (from 1.06 +/- 0.23 to 2.12 +/- 0.99 (ml/cmH(2)O)/kg) (p < 0.05) and a drop in both Raw (from 264.7 +/- 41.5 to 146.6 +/- 39.4 (cmH(2)O/l)/s) and MAP (from 12.4 +/- 3.6 to 5.4 +/- 2.1 cmH(2)O) were observed 48 hours after SLL. These data suggest that SLL is associated with a rapid and significant improvement in pulmonary mechanics, together with an improvement in oxygenation, in newborns with severe MAS. We found that the beneficial effects of SLL on pulmonary mechanics persisted for at least 48 h after introduction of the procedure.

Pulmonary function after surfactant lung lavage followed by surfactant administration in infants with severe meconium aspiration syndrome

Objective: The effect of surfactant lung lavage (SLL) on pulmonary function was examined in neonates with severe form of meconium aspiration syndrome (MAS) (mean ± standard deviation: birth weight, 3178.1 ± 237.6 g; gestational age, 37.7 ± 1.8 weeks). Methods: The infants were on mechanical ventilation and were subjected to SLL with Survanta®. Dynamic compliance (Cdyn), airway resistance (Raw) and mean airway pressure (MAP) were obtained with use of the pneumotachometric method. Measurements of Cdyn, Raw, MAP and time constant (Tc) were compared in the study and control groups and between the groups before SLL and 24 and 48 h after SLL. Results: A significant increase in Cdyn (from 1.06 ± 0.23 to 2.12 ± 0.99 (ml/cmH2O)/kg) (p < 0.05) and a drop in both Raw (from 264.7 ± 41.5 to 146.6 ± 39.4 (cmH2O/l)/s) and MAP (from 12.4 ± 3.6 to 5.4 ± 2.1 cmH2O) were observed 48 hours after SLL. Conclusions: These data suggest that SLL is associated with a rapid and significant improvement in pulmonary mechanics, together with an improvement in oxygenation, in newborns with severe MAS. We found that the beneficial effects of SLL on pulmonary mechanics persisted for at least 48 h after introduction of the procedure.

Corticosteroid treatment in meconium aspiration syndrome: a solution for better outcome?

Corticosteroid treatment in severe meconium aspiration syndrome may afford, especially if started early, some improvement in oxygenation, lung function and pulmonary haemodynamics during the acute phase of the disorder. Still, the effects of corticosteroids on lung tissue perturbations and outcome of diseased infants remain unclear. Conclusion: Further research is needed to determine the clinical significance and optimal timing and dosing of corticosteroid treatment in severe meconium aspiration syndrome.

Efficacy of three treatment schedules in severe meconium aspiration syndrome

To compare three different schedules in severe meconium aspiration syndrome (MAS) treatment: standard, bronchoalveolar lavage (BAL) with diluted surfactant, and diluted surfactant BAL plus a single early dexamethasone dose. Twenty-four full-term newborns with severe MAS (needing mechanical ventilation and with oxygenation index > or = 15) were divided into three groups: group I (historical control group; n = 6) treated with standard therapy; group II (n = 7) treated in the first hours of life with one BAL using diluted surfactant (beractant 5 mg/mL) in a volume of 15 mL/kg in four aliquots; and group III (n = 11) treated with one diluted surfactant BAL and a previous single dose of intravenous dexamethasone (0.5 mg/kg). At 12 h, groups II and III showed a significant improvement in oxygenation index (OI) compared with group I (14.7% and 27.0% vs -19.6% respectively; p = 0.012). Group III also showed a significantly lower OI than group I at 24 h (63.6% vs -27.9%) and at 48 h (87.1% vs 49.6%). Group III, in comparison to group I, showed a lower FiO2 requirement at 12 h (0.66 vs 1), at 24 h (0.4 vs 0.87) and at 48 h (0.35 vs 0.67), and a decrease in the number of days of inhaled nitric oxide administration, mechanical ventilation, oxygen therapy and hospitalisation period. All patients from groups II and III survived and none developed pneumothorax or respiratory infections. Diluted surfactant BAL in the first hours of life combined with an intravenous single dose of dexamethasone may be an effective treatment for severe MAS.

Efficacy of three treatment schedules in severe meconium aspiration syndrome

Aim: To compare three different schedules in severe meconium aspiration syndrome (MAS) treatment: standard, bronchoalveolar lavage (BAL) with diluted surfactant, and diluted surfactant BAL plus a single early dexamethasone dose. Methods: Twenty-four full-term newborns with severe MAS (needing mechanical ventilation and with oxygenation index ± 15) were divided into three groups: group I (historical control group; n= 6) treated with standard therapy; group II (n= 7) treated in the first hours of life with one BAL using diluted surfactant (beractant 5 mg/mL) in a volume of 15 mL/kg in four aliquots; and group III (n = 11) treated with one diluted surfactant BAL and a previous single dose of intravenous dexamethasone (0.5 mg/kg) Results: At 12h, groups II and III showed a significant improvement in oxygenation index (OI) compared with group I (14.7% and 27.0% vs – 19.6% respectively; p= 0.012). Group III also showed a significantly lower OI than group I at 24 h (63.6% vs – 27.9%) and at 48 h (87.1% vs 49.6%). Group III, in comparison to group I, showed a lower FiO2 requirement at 12 h (0.66 vs 1), at 24 h (0.4 vs 0.87) and at 48 h (0.35 vs 0.67), and a decrease in the number of days of inhaled nitric oxide administration, mechanical ventilation, oxygen therapy and hospitalisation period. All patients from groups II and III survived and none developed pneumothorax or respiratory infections. Conclusion: Diluted surfactant BAL in the first hours of life combined with an intravenous single dose of dexamethasone may be an effective treatment for severe MAS.

Exogenous Surfactant Therapy in Newborn Infants

Exogenous surfactant therapy has an established role in the management of neonatal respiratory distress syndrome (RDS). This article summarises the current evidence on surfactant therapy. The use of surfactant for the treatment or prophylaxis of neonatal RDS results in a 30% to 65% relative reduction in the risk of pneumothorax and up to a 40% relative reduction in the risk of mortality. Adverse effects, of which pulmonary haemorrhage is of most concern, are infrequent and long-term follow-up studies of treated patients are reassuring. Natural surfactants have advantages over synthetic surfactants, including a lower frequency of pneumothorax and a lower mortality. Prophylactic administration of surfactant is preferred over ‘rescue’ administration, especially in infants of &lt;30 weeks’ gestation, as it decreases the risk of pneumothorax, pulmonary interstitial emphysema and neonatal mortality. Prophylaxis can be administered after initial resuscitation and stabilisation. In preterm infants who do not receive prophylactic surfactant, the first dose of surfactant should be administered as early as possible – early selective treatment decreases the risk of pneumothorax, pulmonary interstitial emphysema, chronic lung disease and neonatal mortality. A regimen of using multiple doses of surfactant if required has advantages over a single dose regimen. Exogenous surfactant therapy has also been used in neonatal respiratory disorders other than RDS. In trials in severe meconium aspiration syndrome, surfactant therapy reduced the need for extracorporeal membrane oxygenation. Its role in other disorders requires testing. The development and testing of newer surfactants is in progress.

Treatment of severe meconium aspiration syndrome with dilute surfactant lavage.

Despite the development of new adjuvant therapies, meconium aspiration syndrome (MAS) remains a serious respiratory disorder in neonates. Surfactant inactivation by meconium can be overcome by use of exogenous surfactant. This study sought to assess the efficacy and safety of dilute surfactant lavage at 2 different concentrations to treat severe MAS. We retrospectively reviewed the charts of all term infants with a diagnosis of MAS who had an oxygenation index (OI) > 20 during a 2-year period. Tracheobronchial lavage was performed with a dilute surfactant suspension (5 mg/mL or 10 mg/mL) to reach a total dose of 60 to 70 mg/kg of phospholipid, administered in aliquots of 2 mL. The records of 22 patients were reviewed, of whom 12 had undergone lavage. These patients were subdivided into low-concentration (surfactant concentration, 5 mg/mL; n = 6) and high-concentration (surfactant concentration, 10 mg/mL; n = 6) subgroups. There were no significant differences in demographic characteristics between these 2 subgroups. The lavaged infants had a significantly higher arterial partial pressure of oxygen (PaO(2)) 24 hours after lavage than the infants without lavage (178.3 mm Hg vs 80.6 mm Hg, p < 0.05). The incidence of pneumothorax (1/12 vs 7/10, p < 0.05) and requirement for inhaled nitric oxide (5/12 vs 9/10, p < 0.05) were significantly lower in the lavaged group. All infants tolerated the procedure well except for 2 with transient complications. There were no significant differences in duration of lavage, response and complications between subgroups lavaged at low and high surfactant concentration. Early lavage with dilute surfactant solution at a phospholipid concentration of either 5 mg/mL or 10 mg/mL is effective for the treatment of severe MAS. Further large-scale, prospective, randomized, controlled trials are necessary to establish the optimal dose, concentration, surfactant product, and instillation method of this treatment before it can be recommended for routine use.

Delayed institution of extracorporeal membrane oxygenation is associated with increased mortality rate and prolonged hospital stay

Background/Purpose: Severe meconium aspiration syndrome (MAS) is a frequent indication for extracorporeal membrane oxygenation (ECMO). Trials of less invasive cardiopulmonary support may result in fewer infants treated with ECMO but could delay institution of ECMO. The authors hypothesized that those infants with severe MAS who are treated with ECMO early will have a lower mortality rate and a shorter hospital course than those who receive delayed ECMO. Methods: A retrospective review of all patients with MAS in the national extracorporeal life support (ELSO) registry for the decade 1989 through 1998 was performed. Data from the ELSO registry were examined for demographics, clinical parameters, and treatment course. Patients were divided into 3 groups based on the time from birth to institution of ECMO: group 1, 0 to 23 hours; group 2, 24 to 96 hours; and group 3, greater than 96 hours. These groups were compared for survival, duration of extracorporeal support, and duration of ventilatory support after ECMO. Statistical relevance was determined by analysis of variance (ANOVA) and Tukey's post-hoc test. Results: A total of 3,235 of 4,002 patients with MAS had complete information on duration of mechanical ventilation. Overall mortality rate was 5.8%. The mortality rate in group 1 (n = 1,266) was 4.8%, group 2 (n = 1,568) 6.0%, and group 3 (n = 401) 7.7%. An increased time to ECMO was associated with a significant increase in mortality rate (P <.05). This also was associated with significant increases in the length of the ECMO run (157 ± 4 v 130 ± 2 hours, P =.02) and duration of post-ECMO ventilation (157 ± 17 v 118 ± 3 hours; P <.001). Those patients in groups 1 and 2 who did not respond to a trial of high-frequency oscillatory ventilation had significantly longer ECMO runs (129 ± 2 v 113 ± 1 hours; P =.001) and longer post-ECMO ventilator courses (137 ± 2 v 114 ± 1 hours; P =.002) than those who did not. Conclusions: Delay in institution of ECMO for MAS results in prolonged ECMO and need for post-ECMO ventilation. Consideration should be given to instituting ECMO earlier in patients with severe MAS. J Pediatr Surg 37:7-10. Copyright © 2002 by W.B. Saunders Company.

Severe meconium aspiration syndrome is not caused by aspiration of meconium

Meconium aspiration syndrome can present clinically with different degrees of severity, ranging from a mild form of respiratory compromise to severe forms that may result in perinatal death despite mechanical ventilation or extracorporeal membrane oxygenation. However, advances in our knowledge concerning meconium aspiration syndrome have revealed that most cases of severe meconium aspiration syndrome are not in fact causally related to the aspiration of meconium but rather are caused by other pathologic processes occurring in utero, primarily chronic asphyxia and infection. Proper understanding of the causative processes underlying fetal or neonatal compromise in these cases is essential to direct future research into preventive or therapeutic treatments and for counseling of the parents of an affected child. (Am J Obstet Gynecol 2001;185:931-8.)

Variables Associated With Meconium Aspiration Syndrome in Labors With Thick Meconium

Objective: To examine the possible maternal and fetal variables associated with meconium aspiration syndrome in labors with thick meconium. Study design: The fetal heart rate tracings, cord pH, Apgar scores and maternal risk factors were evaluated in singleton pregnancies with vertex presentation and thick meconium in labor. The study included 33 consecutive fetuses which developed a moderate or severe meconium aspiration syndrome and 104 consecutive fetuses which had a favorable outcome. Results: Significant differences between fetuses with meconium aspiration syndrome and healthy fetuses were found in the following parameters: baseline FHR (154±17 vs. 136±10, P<0.0001), small accelerations/30 min (1.47±1.52 vs. 3.04±1.2, P<0.0001), large accelerations/30 min (1.46±1.96 vs. 3.5±2.31, P<0.0003), decelerations/30 min (4.9±3.9 vs. 2.4±2.1, P<0.0034), number of fetuses with reduced beat-to-beat variability (9/33 vs. 0/104, P<0.0001), cord pH (7.21±0.09 vs. 7.33±0.08, P<0.0013) and Apgar scores at 1 min (5±2 vs. 8±1, P<0.0001) and Apgar scores at 5 min (8±2 vs. 9.7±0.6, P<0.0001). Maternal risk factors were found in two of 33 sick infants and in 13 of 104 healthy infants. Conclusion: Thick meconium by itself is not associated with adverse fetal outcome. However, the incidence of meconium aspiration syndrome increases in cases of a non-reassuring FHR.

Meconium aspiration syndrome in term neonates with normal acid-base status at delivery: Is it different?

Objective: Our aim was to compare the clinical characteristics of meconium aspiration syndrome in cases with pH ≥7.20 and in those with pH <7.20. Study Design: Medical records of diagnostic codes from the International Classification of Diseases, Ninth Revision, were used to identify neonates with severe meconium aspiration syndrome who had been delivered at our institution from 1994 through 1998. Severe meconium aspiration syndrome was defined as a mechanical ventilator requirement of >48 hours. Clinical data including neonatal outcomes of cases of meconium aspiration syndrome associated with umbilical pH ≥7.20 at delivery were compared with data on outcomes of cases with pH <7.20. Results: During this 4-year study period, 4985 singleton term neonates were delivered through meconium-stained amniotic fluid. Forty-eight cases met all study criteria, and pH values at delivery were as follows: pH ≥7.20, n = 29, and pH <7.20, n = 19. There were no differences between groups in the incidence of clinical chorioamnionitis, in the presence of meconium below the vocal cords, or in birth weight. Neonates with meconium aspiration syndrome and umbilical pH ≥7.20 at delivery developed seizures as often as those with pH <7.20 (20.1% vs 21.1%; P = 1.0). Conclusion: Normal acid-base status at delivery is present in many cases of severe meconium aspiration syndrome, which suggests that either a preexisting injury or a nonhypoxic mechanism is often involved. (Am J Obstet Gynecol 2001;184:1422-6.)

Endotracheal intubation at birth for preventing morbidity and mortality in vigorous, meconium-stained infants born at term.

On the basis of evidence from non-randomised studies, it has been recommended that all babies born through thick meconium should have their tracheas intubated so that suctioning of their airways can be performed. The aim is to reduce the incidence and severity of meconium aspiration syndrome. However, for term babies who are vigorous at birth endotracheal intubation may be both difficult and unnecessary. To determine if endotracheal intubation and suction of the airways at birth in vigorous term meconium-stained babies is more beneficial than routine resuscitation including aspiration of the oro-pharynx. The search was made from Oxford Database of Perinatal Trials, the Neonatal Trials Registry of the Cochrane Neonatal Collaborative Review Group and information obtained from knowledgeable practising neonatologists. Randomised trials which compared a policy of routine vs no (or selective) use of endotracheal intubation and aspiration in the immediate management of vigorous term meconium-stained babies at birth. Data regarding clinical outcomes including mortality, meconium aspiration syndrome, other respiratory conditions, pneumothorax, need for oxygen supplementation, stridor, convulsions and hypoxic-ischaemic encephalopathy were abstracted and analysed using Revman 3.1.1. Four randomised controlled trials of endotracheal intubation at birth in vigorous term meconium-stained babies were identified. Meta-analysis of these trials does not support routine use of endotracheal intubation at birth in vigorous meconium-stained babies to reduce mortality, meconium aspiration syndrome, other respiratory symptoms or disorders, pneumothorax, oxygen need, stridor, HIE and convulsions. Routine endotracheal intubation at birth in vigorous term meconium-stained babies has not been shown to be superior to routine resuscitation including oro-pharyngeal suction. This procedure cannot be recommended for vigorous infants until more research is available.

Variables associated with meconium aspiration syndrome in labors with thick meconium

Objective: To examine the possible maternal and fetal variables associated with meconium aspiration syndrome in labors with thick meconium. Study design: The fetal heart rate tracings, cord pH, Apgar scores and maternal risk factors were evaluated in singleton pregnancies with vertex presentation and thick meconium in labor. The study included 33 consecutive fetuses which developed a moderate or severe meconium aspiration syndrome and 104 consecutive fetuses which had a favorable outcome. Results: Significant differences between fetuses with meconium aspiration syndrome and healthy fetuses were found in the following parameters: baseline FHR (154±17 vs. 136±10, P<0.0001), small accelerations/30 min (1.47±1.52 vs. 3.04±1.2, P<0.0001), large accelerations/30 min (1.46±1.96 vs. 3.5±2.31, P<0.0003), decelerations/30 min (4.9±3.9 vs. 2.4±2.1, P<0.0034), number of fetuses with reduced beat-to-beat variability (9/33 vs. 0/104, P<0.0001), cord pH (7.21±0.09 vs. 7.33±0.08, P<0.0013) and Apgar scores at 1 min (5±2 vs. 8±1, P<0.0001) and Apgar scores at 5 min (8±2 vs. 9.7±0.6, P<0.0001). Maternal risk factors were found in two of 33 sick infants and in 13 of 104 healthy infants. Conclusion: Thick meconium by itself is not associated with adverse fetal outcome. However, the incidence of meconium aspiration syndrome increases in cases of a non-reassuring FHR.

Advances in management of meconium aspiration syndrome.

Meconium Aspiration Syndrome (MAS) is a leading cause of respiratory distress in the newborn. Antenatal diagnosis of meconium stained amniotic fluid and fetal distress is important to reduce morbidity and mortality in the neonates. Amnioinfusion of saline and tracheal suctioning of meconium are preventive interventions. Babies with MAS who continue to have respiratory distress need to be put on conventional ventilators. Increasing hypoxia, hypercarbia and barotrauma warrants changing to high frequency oscillatory ventilation. Pulmonary hypertension is an important complication which should be promptly recognized. Nitric oxide therapy used with high frequency ventilation has improved the outcome of babies with severe MAS and pulmonary hypertension. Some of these babies who continue to worsen clinically need to be put on ECMO circuit. Surfactant infusion in babies with MAS has been shown to improve gas exchange, resolve pulmonary hypertension and decrease oxygenation index. Total and partial liquid ventilation with perflurocarbon improves oxygenation, increases lung expansion and increases pulmonary blood flow in model studies of animals with MAS. Surfactant infusion and liquid ventilation are newer promising modes of therapeutic interventions in babies with severe MAS.

Prediction of surfactant dysfunction in term infants by the click test.

Pulmonary surfactant dysfunction (inactivation, deficiency) has been implicated in term neonates with respiratory failure. This study has evaluated the click test, a biophysical test for surfactant function, which will be useful in rapidly and reliably identifying term neonates with surfactant dysfunction. Samples of tracheal and or gastric aspirates (0.2 ml) from 55 neonates, varying from 36 to 42 weeks of gestational age, with respiratory distress and fractional inspired oxygen concentration requirements of > 0.5 were shaken with 95% ethanol. Once bubbles formed the samples were examined in air-free water under a microscope. In a positive click test, the bubbles rhythmically increase and then decrease in size, denoting the presence of active surfactant. When few bubbles were observed, the specimen was labelled as equivocal, and if none were seen, it was called negative. Surfactant dysfunction (negative or equivocal test) was consistently seen in respiratory distress syndrome (RDS), transient tachypnea of the newborn, and severe meconium aspiration syndrome (MAS). Preliminary data suggest that the click test will provide a rapid and early diagnosis of surfactant dysfunction in term neonates. This should facilitate early treatment with exogenous surfactant in RDS, by early diagnosis of surfactant deficiency, and provide justification for immediate and ongoing surfactant treatment in newborns with MAS. The click test can provide a diagnostic tool for surfactant dysfunction and deficiency in randomized controlled trials of therapy in those disease states in which exogenous surfactant therapy may be useful.

Lung lavage with a saline volume similar to functional residual capacity followed by surfactant administration in newborns with severe meconium aspiration syndrome

Lung lavage with a saline volume similar to functional residual capacity followed by surfactant administration in newborns with severe meconium aspiration syndrome