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PubMed2006

Inhibition of meconium-induced cytokine expression and cell apoptosis by pretreatment with captopril.

OBJECTIVE: To study whether pretreatment of newborn lungs by captopril inhibits meconium-induced lung injury and inflammatory cytokine expression. DESIGN: Four groups of 2-week-old rabbit pups were used for the study: group 1, saline instilled rabbits; group 2, captopril-pretreated rabbits; group 3, meconium-instilled rabbits; and group 4, captopril-pretreated and then meconium-instilled rabbits. Each group was studied at different time points: 0, 2, 4, 8, and 24 hours after instillation of meconium. Experiments were done at the University of Illinois and Michael Reese Hospital at Chicago. After treatment and instillation of meconium, the right lung was fixed with formalin, and 2-mum slices were obtained for immunohistochemistry. The left lung was used for obtaining of lung lavage and measurement of total proteins (for enzyme-linked immunosorbent assay) and mRNA (for reverse transcription-polymerase chain reaction) purification. RESULTS: We found that meconium induces inflammatory cytokine expression and apoptotic lung cell death. In situ end labeling revealed a dramatic DNA fragmentation in the meconium group, which supports the presence of apoptosis. Using enzyme-linked immunosorbent assay, we demonstrated increase of interleukin 6 and interleukin 8 cytokines in meconium-instilled lungs, which were significantly decreased in captopril-pretreated lungs. Captopril pretreatment also decreased meconium-induced cell death and angiotensinogen expression. We believe this effect is explained by the ability of captopril to decrease processing of ANGEN to angiotensinogen (ANG) I and finally to ANG II. It suggests that captopril inhibits ANG II-induced lung cell apoptosis. CONCLUSION: Our results demonstrate that captopril pretreatment significantly inhibits meconium-induced lung cell death, cytokine, and ANGEN expression in newborn lungs.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2003

Meconium enhances the growth of perinatal bacterial pathogens.

OBJECTIVE: To demonstrate the effects of meconium on growth of bacterial pathogens, which are common causes of intra-amniotic infection and neonatal sepsis. METHODS: Meconium collected from 9 healthy neonates was suspended as a 20% solution using sterile saline. In experiment 1, separate test tubes of meconium solution and sterile saline (the control) were individually inoculated with 10(6) colony-forming units of a single species of the following test pathogens: Escherichia coli, Enterococcus faecalis, Group B Streptococcus, Staphylococcus aureus, Pseudomonas aeruginosa, and Listeria monocytogenes. After incubation at 37 degree C for 24 hours, 1 L each of the bacterial-meconium and bacterial-saline solutions was inoculated onto 5% sheep blood agar. After 24 hours of incubation, the number of developing colonies was counted. In experiment 2, equal volumes of meconium and saline solutions were inoculated with 10(5) colony-forming units of either E. coli or Group B Streptococcus. At intervals of 6, 9, and 24 hours post-incubation, 1 L each of the bacterial-meconium and bacterial-saline solutions was inoculated onto 5% sheep blood agar plates, and colonies were counted after overnight incubation. RESULTS: In the first experiment, 24 hours of incubation resulted in bacterial amplification in the meconium solution from an initial inoculum of 10(6) colony-forming units/mL to 10(9) colony-forming units/mL. In contrast, the same inoculation of saline solution (control) showed no increase in colony counts over the same time interval. For E. coli and Group B Streptococcus in experiment 2, growth enhancement in meconium was seen as early as 6 hours, as colony counts of a test species increased from 105 colony-forming units/mL to 10(9)-10(10) colony-forming units/mL. CONCLUSION: Enhanced growth of perinatal pathogens in meconium was constantly observed, and can occur as early as 6 hours after bacterial interaction of meconium.

Bacteria↗
PubMed2003

Meconium peritonitis in utero: prenatal sonographic findings and clinical implications.

BACKGROUND: Prenatal ultrasound scans reveal variable features of fetal meconium peritonitis. For better understanding of the natural history and postnatal prognosis of meconium peritonitis, we clarified the significance of ultrasound findings in the outcomes of fetuses with meconium peritonitis. METHODS: Between 1991 and 2001, fetuses who underwent evaluation for meconium peritonitis were retrospectively analyzed. The diagnosis was made by intra-abdominal calcifications, meconium pseudocyst, or meconium ascites, which were postnatally confirmed by the operative findings and/or abdominal plain films. According to the final ultrasound findings before labor, patients were classified into 3 groups: type I, large meconium ascites; type II, a large pseudocyst; type III, intra-abdominal calcifications, small meconium ascites and/or a shrinking pseudocyst. RESULTS: Nineteen fetuses (6 boys and 13 girls) were collected. Mean gestational age at diagnosis was 29.1 +/- 5.3 weeks and mean follow-up before delivery was 7.5 +/- 6.2 weeks. Mean gestational age at birth was 36.8 +/- 6.2 weeks. Six fetuses (31.5%) were delivered before 37 weeks of gestation. Type I was found in 5 (26.3%), type II in 3 (15.8%), and type III in 11 (57.9%). Intra-abdominal calcifications were identified in 15 cases (78.9%), polyhydramnios in 4 (21.1%), and oligohydramnios in 3 (15.8%). Cardiopulmonary resuscitation at birth was required in 2 cases (type I). Twelve cases (63.2 %) were spontaneous perforations. Of 7 other cases (36.8%) studied, 6 had intestinal atresia and 1 had associated defects resulting in bowel perforation. Postnatal follow-up revealed all but 2 (died of sepsis and prematurity, respectively) doing well. CONCLUSIONS: Our results indicate that detailed fetal ultrasound scans are crucial for providing a prenatal diagnosis and proper perinatal management of meconium peritonitis. From the viewpoints of our study, proper prenatal counseling and risk evaluation should be offered to the parents of the fetuses with meconium peritonitis.

Adult↗
PubMed1992

An assessment of the use of meconium alone as an indication for fetal blood sampling.

OBJECTIVE: To assess the validity of meconium as an indication for fetal blood sampling. METHODS: The study design was a prospective observational study in a teaching hospital. Fetal blood samples were taken from 401 women. One hundred sixty-five patients had meconium-stained amniotic fluid (77 of whom had no cardiotocographic abnormalities). In the remaining 236 patients, the indication for fetal blood sampling was cardiotocographic abnormalities without meconium. The main outcome measures were the values of pH and base excess obtained at fetal blood sampling, 1-minute Apgar scores, and umbilical artery pH values. RESULTS: Patients with meconium alone as an indication for fetal blood sampling had higher scalp sample pH values (P < .001) and 1-minute Apgar scores (P < .01) than laboring patients with both meconium and cardiotocographic abnormalities. The patients with meconium alone had higher scalp pH values than patients with cardiotocographic abnormalities but no meconium (P < .001). In only two patients with meconium alone was a fetal scalp pH less than 7.20 (both infants had good Apgar scores at delivery). However, when cardiotocographic abnormalities were present, the finding of meconium was significant, resulting in lower 1-minute Apgar scores (P < .01) despite a lack of difference in fetal blood sample pH values. CONCLUSION: In the absence of cardiotocographic abnormalities, meconium is not an indication for fetal blood sampling.

Adult↗
PubMedDate not supplied

Measurement of cocaine and metabolites in urine, meconium, and diapers by gas chromatography/mass spectrometry.

Analytical methods were evaluated for measuring cocaine (CO), benzoylecgonine (BE), and ecgonine methyl ester (EME) in urine and methanolic extracts from meconium and diapers by isotope dilution gas chromatography/mass spectrometry (GC/MS). Volatile derivatives of the extracted drugs were generated before GC/MS analysis. Methanolic extracts from meconium and diapers were reconstituted in drug-free urine and treated as above. The limit of detection for the GC/MS method was calculated to be approximately 11 ng per mL. Within-run coefficients of variation (CVs) for urinary CO, BE, and EME were 5.7, 5.3, and 11.4 percent, respectively (N = 10); corresponding CVs for meconium 6.4, 10.7, and 21.9 percent (N = 8). Quantitative results were linear from 25 to 10,000 ng per g of meconium and 25 to 5,000 ng per mL of urine. Day-to-day precision varied from eight percent (CV) for BE in refrigerated or frozen urine to 34 percent for EME in refrigerated meconium. Recoveries of CO, BE, and EME from urine were 63, 19, and 42 percent, respectively; corresponding recoveries from meconium were 64, 21, and 25 percent. Cocaine and metabolites were extracted from wet but meconium-free diapers into methanol, which was evaporated before reconstituting in drug-free urine and extraction on a solid phase column. The CO, BE, and EME were detected in previously drug-free meconium after portions were deposited in a diaper which was wet with drug-positive urine. Unless precautions are taken to prevent extracorporeal contamination of meconium with urine, concentrations of CO and metabolites in meconium may be substantially augmented by contamination with urine. Analysis by GC/MS of CO and metabolites extracted from diapers provides an attractive alternative to collection of urine, which is difficult and may cause discomfort for the neonate.

Cocaine↗
PubMed1998

Liquid ventilation for treatment of meconium aspiration syndrome in a piglet model.

We tested the hypothesis that liquid ventilation (LV) with perfluorocarbon (PFC) can remove aspirated meconium and improve lung function in experimental meconium aspiration syndrome (MAS). PFC (FC-77) was used as the medium in LV. Sixteen piglets were divided into control and LV groups (8 animals/group). All animals received slurry meconium (20% in normal saline) via endotracheal instillation at baseline. Thirty minutes later, the LV group received 15 cycles of LV. Pulmonary mechanics, arterial blood gases, and hemodynamic values were recorded at baseline, and 30, 60, 120, 180, and 240 minutes after meconium instillation. Chest radiographs and lung sections were taken and scored at the end of the study. The percentage of meconium cleared by LV was calculated as the ratio of the dry weight of washings to that of meconium instilled, multiplied by 100. The procedure was tolerated well by the animals. LV cleared 25% +/- 7% of the instilled meconium. Tidal volume (9.5 +/- 2.0 vs 7.1 +/- 0.8 mL/kg, p = 0.012), respiratory system compliance (2.32 +/- 0.60 vs 1.60 +/- 0.24 mL/cmH2O, p = 0.01), PaO2 (65 +/- 7 torr vs 55 +/- 6 torr, p = 0.0067), and arterial to alveolar oxygen ratio (0.14 +/- 0.01 vs 0.12 +/- 0.01, p = 0.0077) were improved in the LV group at 60 minutes after meconium instillation compared with those of the control group. The scores of exudative debris (1.7 +/- 0.3 vs 2.1 +/- 0.2) and visible meconium (1.4 +/- 0.5 vs 2.1 +/- 0.5) were significantly lower in the LV group. In conclusion, short-term L.V with FC-77 can partially remove aspirated meconium from the lungs and improve pulmonary function transiently.

Animals↗
PubMed2000

Inhibitory effect of meconium on pulmonary surfactant function tested in vitro using the stable microbubble test.

UNLABELLED: Meconium aspiration syndrome is related to mechanical obstruction of the airways and subsequent chemical pneumonitis. It has also been suggested that meconium causes inhibition of surfactant function. To assess its inhibitory effect on surfactant function in vitro, we used a stable microbubble (SM) test that was thought to reflect the adequacy of pulmonary surfactant. The mixtures were prepared by adding serial dilutions of human meconium to various concentrations of Surfactant-TA (Surfacten). The SM count at each concentration of surfactant significantly increased with the increasing concentration of surfactant. This shows that the SM test closely reflects the quantified function of surfactant. When various concentrations of meconium were added to the surfactant concentration of 0.05 mg/ml and 0.25 mg/ml, the SM test results were decreased even at low concentrations of meconium. Also the increase in the meconium concentration caused a decrease in the SM test result, which was dependent on the surfactant and the meconium concentration, accordingly. These results suggest that meconium inhibits surfactant function. CONCLUSION: The stable microbubble test is an effective indirect method that tests the changes in surfactant quantity. In the in vitro experiment, we observed an inhibitory effect of meconium on the surfactant activity using the stable microbubble test.

Biological Products↗
PubMed1992

Meconium aspiration syndrome: reflections on a murky subject.

Meconium-stained amniotic fluid occurs in approximately 12% of live births. In approximately one third of these infants meconium is present below the vocal cords. However, meconium aspiration syndrome develops in only 2 of every 1000 live-born infants. Ninety-five percent of infants with inhaled meconium clear the lungs spontaneously. Recent investigations have suggested that a reexamination of our assumptions about the etiology of meconium aspiration syndrome is in order. Several authors have provided evidence that support the hypothesis that it is not the inhaled meconium which produces the primary pathologic condition of meconium aspiration syndrome but rather it is fetal asphyxia that is the etiologic agent. Asphyxia in utero produces pulmonary vasospasm and hyperreactivity of the pulmonary vessels. With severe asphyxia the fetal lungs undergo pulmonary vascular damage with pulmonary hypertension. The damaged lungs are then unable to clear the meconium. In the most severe cases there is right-to-left shunting and persistent fetal circulation with subsequent fetal death. The incidence of meconium aspiration may thus be essentially unaffected by current obstetric and pediatric interventions at birth. For the asphyxiated or distressed infant we recommend suctioning at birth and tracheal intubation. In the healthy fetus observation may be sufficient.

Asphyxia Neonatorum↗
PubMed1992

Prophylactic amnioinfusion improves outcome of pregnancy complicated by thick meconium and oligohydramnios.

OBJECTIVE: The null hypothesis is that the use of intrapartum amnioinfusion in labors complicated by the presence of thick meconium and oligohydramnios will not decrease the incidence of fetal distress, cesarean delivery, meconium aspiration, or meconium aspiration syndrome. STUDY DESIGN: One hundred seventy term and postterm patients with thick meconium and oligohydramnios were randomly chosen to receive amnioinfusion or standard obstetric care without amnioinfusion. The frequency of fetal distress, cesarean section, meconium aspiration, and meconium aspiration syndrome were subject to chi 2 analysis, Student's t test, or Fisher's exact test. RESULTS: The rate of fetal distress was significantly reduced in the amnioinfusion group compared with controls (three of 85 vs 19 of 85, relative risk 0.15, 95% confidence interval 0.06 to 0.42). The rate of cesarean section for fetal distress was significantly reduced in the amnioinfusion group (two of 85 vs 17 of 85, relative risk 0.118, confidence interval 0.03 to 0.49). The rates of meconium aspiration (four of 85 vs 33 of 85, relative risk 0.12, confidence interval 0.0449 to 0.327) and meconium aspiration syndrome (0 of 85 vs five of 85, relative risk 0.09, confidence interval 0.009 to 0.872) were significantly reduced by amnioinfusion. CONCLUSIONS: Amnioinfusion improves the outcome in pregnancies complicated by thick meconium and oligohydramnios.

Amnion↗
PubMed2000

Intrapartum amnioinfusion for meconium-stained fluid: meta-analysis of prospective clinical trials.

OBJECTIVE: To evaluate the effectiveness of intrapartum prophylactic amnioinfusion in pregnancies complicated by meconium-stained amniotic fluid. DATA SOURCES: We identified prospective clinical trials of amnioinfusion in pregnancies complicated by meconium-stained amniotic fluid (AF) published in English by using computerized databases, references in published studies, and index reviews. METHODS OF STUDY SELECTION: We analyzed prospective studies of intrapartum amnioinfusion for meconium-stained AF. In every case, group allocation was based exclusively on meconium in AF. Only published studies with clearly documented outcome data were included. The trials were evaluated for meconium below the vocal cords, meconium aspiration syndrome, fetal acidemia, cesarean delivery, and postpartum endometritis. Each trial was evaluated for the quality of its methodology, inclusion and exclusion criteria, adequacy of randomization, amnioinfusion protocols, definition of outcomes, and statistical analyses. TABULATION, INTEGRATION, AND RESULTS: Thirteen studies met inclusion criteria for our systematic review. Odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated for each outcome. Estimates of ORs and risk differences for dichotomous outcomes were calculated using random and fixed-effects models. We tested for homogeneity across the studies. We found that intrapartum amnioinfusion significantly reduced the frequency of meconium aspiration syndrome (OR 0.30; 95% CI 0.19, 0. 46), of meconium below the vocal cords, and neonatal acidemia. Subjects allocated to receive amnioinfusion also had a significantly lower overall cesarean rate (OR 0.74, 95% CI 0.59, 0.93) without increased postpartum endometritis. CONCLUSION: Amnioinfusion in cases of meconium-stained fluid significantly improves neonatal outcome, lowers the cesarean delivery rate, and does not increase the postpartum endometritis rate.

Amnion↗
PubMed2002

Meconium stimulates neutrophil oxidative burst.

Acute lung injury induced by meconium aspiration is characterized by rapidly developing pulmonary inflammation with influx of activated polymorphonuclear cells. To evaluate the role of meconium in the activation of these invading cells, we described the oxidative capacity of circulating neutrophils after intratracheal administration of thick human meconium in pigs. We also examined the direct effects of varying meconium concentrations on the oxidative burst of human neutrophils in vitro. In neutrophils isolated from meconium-insufflated pigs, phorbol myristate acetate stimulation led to an average 11.7-fold increase in production of reactive oxygen species, measured by chemiluminescence, whereas the increase in control cells from saline-instilled pigs was only 3.1-fold, p =.012 between the groups. Activation of unstimulated human leukocytes by meconium resulted in a dose-dependent response. The lowest meconium concentration (0.2 mg/mL) had an inhibitory effect on neutrophil activation, whereas higher concentrations of meconium (1 and 2 mg/mL) increased neutrophil oxygen radical production progressively. These results thus indicate that moderate and high concentrations of aspirated meconium rapidly activate circulating neutrophils with a resulting oxidative burst contributing to pulmonary tissue injury, whereas low contamination of the aspirated material may in fact suppress the development of oxidative lung injury.

Animals↗
PubMed1994

Meconium staining of the liquor in a low-risk population.

Although the significance of meconium-stained amniotic fluid as a sign of fetal distress remains controversial, its presence remains a concern to both obstetricians and neonatologists since signs of asphyxia and meconium staining are associated with an increase in perinatal morbidity and mortality. The aim of this study was to evaluate the role of meconium staining of the liquor in the low-risk obstetric population in terms of fetal distress and perinatal morbidity and mortality. In a prospective cohort study at a referral hospital and at one of two municipal clinics, women with a singleton pregnancy of 37 to 42 weeks gestation and with no pre-defined risk factor were recruited into the study. Study patients comprised those with meconium staining of the liquor and controls comprised similar women but with clear liquor. Meconium staining of the liquor was associated with poor outcome in all the outcome measures assessed. Fetal heart rate (FHR) abnormality was more closely associated with adverse outcome than meconium staining, and thin meconium alone was not associated with any adverse outcome except respiratory distress. Women with thin meconium in the presence of normal FHR can therefore be safely managed at the clinic level. Thick meconium itself was a risk factor for poor outcome, more so if associated with FHR abnormality, and should be an indicator for early referral.

Amniotic Fluid↗
PubMed1994

Oxytocin augmentation in arrest disorders in the presence of thick meconium: influence on neonatal outcome.

The objective of this report was to study the effect of oxytocin augmentation in arrest disorders in the presence of thick meconium on meconium aspiration and fetal acidosis. We evaluated 3,321 singleton, term deliveries with cephalic presentation at our institution. Eight percent (253/3,321) had thick meconium in labor, and these patients comprised the study sample. Of the 253 women with thick meconium, 84 had an arrest disorder in the active phase of labor with normal fetal heart rate tracing at the time of diagnosis. Seventy-four percent (62/84) of the women with arrest were treated with oxytocin (group 1) and 26% (22/84) delivered by cesarean section without augmentation (group 2). There was a significant (p < 0.05) increase in the incidence of meconium aspiration (14.5 vs. 4.5%) and low (< 7.20) cord arterial pH (27.8 vs. 4.5%) in patients who received oxytocin compared to those who did not. Of the women who received oxytocin, 36 delivered vaginally, and 2 neonates had meconium aspiration. The remaining 26 women had cesarean sections following oxytocin augmentation and had a significantly higher (p < 0.05) frequency of meconium aspiration (26.9 vs. 4.5%) and low cord arterial pH (38.5 vs. 4.5%) compared to women who had cesarean sections without oxytocin augmentation. The findings suggest that oxytocin augmentation in arrest disorders in the presence of thick meconium may be associated with a higher risk of meconium aspiration and low umbilical cord arterial pH.

Adult↗
PubMed1989

Meconium-induced vasocontraction: a potential cause of cerebral and other fetal hypoperfusion and of poor pregnancy outcome.

Chronically meconium-stained fetuses may ultimately suffer cerebral palsy and other devastation. The mechanism is unknown. Innocuous pregnancy complications may cause some fetuses to discharge meconium, which may become hazardous, independently of aspiration. We herein report previously undescribed, meconium-induced umbilical and placental vascular necrosis. To investigate whether meconium causes vasocontraction, we tested umbilical vein tissue with an isometric transducer connected to a polygraph. The specimens were suspended in a 30-mL organ bath with Krebs solution (pH, 7.4; temperature, 37 degrees C; under aeration with 95% O2 and 5% CO2). We exposed the tissue to meconium and compared meconium-induced vasocontraction with that induced by Krebs solution and 10(-5) molar serotonin. Meconium maximally produced 62.9% of serotonin-induced vasocontraction. Krebs solution and boiled meconium did not produce vasocontraction. We hypothesize that meconium may cause placental and umbilical cord vasocontraction, cerebral and other fetal hypoperfusion, and major poor outcome.

Asphyxia Neonatorum↗
PubMed2004

Intratracheal albumin reduces interleukin-8 in tracheobronchial aspirates in piglets after meconium aspiration.

Meconium aspiration induces pulmonary inflammation and reduces surfactant function. We hypothesized that albumin mixed with meconium attenuates pulmonary inflammation and improves surfactant function after meconium aspiration. We measured the concentration of free fatty acids (FFA) in the meconium (110 mg dry weight/mL) and added albumin to provide a molar FFA:albumin ratio of 1:1. Newborn piglets, 0-2 day of age, artificially ventilated and exposed to hypoxemia by ventilation with 8% O2, were randomized to group A receiving meconium (n = 12), or group B receiving meconium + albumin (n = 12), 3 ml/kg intratracheally. The animals were reoxygenated for 8 h. Reoxygenation was started when mean arterial blood pressure was < 20 mm Hg or base excess was < -20 mmol/L. During 8 h of reoxygenation the interleukin-8 concentrations in tracheobronchial aspirates increased 5-fold more in the meconium vs. the meconium + albumin groups (93 +/- 56 vs. 18 +/- 4 pg/mL, p < 0.005). There were no differences between the groups for tumor necrosis factor alpha in tracheobronchial aspirates, recruitment of inflammatory cells in the airspaces or surfactant function in bronchoalveolar lavage fluid. In conclusion, albumin significantly decreased interleukin-8 concentrations in tracheobronchial aspirates after meconium aspiration.

Animals↗
PubMed1994

Meconium-stained amniotic fluid and respiratory complications: impact of selective tracheal suction.

OBJECTIVE: To determine prospectively the incidence of several pulmonary diagnoses among infants born through clear or meconium-stained amniotic fluid (AF) managed by a selective approach to tracheal intubation. METHODS: All live births greater than 36 weeks' gestation occurring between January 1990 and December 1992 were included. Diagnostic criteria for several respiratory disorders were determined prospectively and monitored. Infants with light meconium and vigorous infants with moderate to thick meconium were selectively not suctioned. A control group of infants with clear AF matched for gestational age and year of birth was randomly selected for comparison. The incidence and severity of respiratory disease were compared between the groups. RESULTS: Of 4938 live births, 799 (16%) had meconium-stained AF (light, 334; moderate to thick, 465). Compared to 211 infants with moderate to thick meconium selectively not suctioned, 196 suctioned infants had significantly greater rates of abnormal fetal heart rate (FHR) patterns, fetal acidosis, low Apgar scores at 5 minutes, need for resuscitation, and neonatal intensive care unit admission. Meconium aspiration syndrome was significantly more common in suctioned infants as compared to those selectively not suctioned, those with light meconium, and those with clear fluid (11 versus 3 versus 0 versus 0%; P < .01). The need for ventilator or oxygen support was similar between infants with clear fluid, lightly stained fluid, and moderate to thick fluid who were selectively not suctioned, but was significantly greater among suctioned infants (P < .01). CONCLUSIONS: We conclude that a selective approach to tracheal intubation and suction of infants with meconium-stained AF was not associated with increased pulmonary morbidity or mortality. Postnatal management of neonates at greatest risk of meconium aspiration syndrome does not necessarily prevent adverse pulmonary outcome.

Amniotic Fluid↗
PubMed1991

Meconium for drug testing.

Samples of meconium from 28 neonates born to women suspected of drug abuse were tested for drugs of abuse (ie, cocaine, morphine, codeine, and marijuana). In each case, testing of urine from the mother, the newborn, or both had been ordered by the attending physician because of suspected maternal drug abuse. Seventeen (61%) of 28 meconium samples tested positive; 28 (60%) of 47 urine samples were positive. Meconium test results were concordant with the results of maternal or newborn urine testing in 24 (86%) of the 28 cases. In three cases, meconium was positive for cocaine when newborn urine was negative; in one case, meconium was negative when maternal urine was positive for cocaine. Compared with the combination of maternal and newborn urine testing, meconium testing had an 82% positive predictive value (14/17) and a 91% negative predictive value (10/11). Collection of meconium is simpler and more reliable than collection of urine, and testing of meconium was easily incorporated into routine procedures at a busy commercial laboratory. Meconium is a useful sample for drug detection in newborns.

Cocaine↗
PubMed1992

Removing meconium from infant tracheae. What works best?

OBJECTIVE: At least nine mechanical devices are available for suctioning the tracheae of meconium-stained newborns. To our knowledge, the efficacy of these devices, as well as various suction pressures and patterns, has not been previously compared. We performed this investigation to assess these variables. DESIGN: Fourteen suction techniques (combinations of device, suction pressure, and suction intermittency) were evaluated sequentially in the trachea of each of 14 in vitro newborn piglets (1 to 4 days old); the order was randomized using a Latin square design. We chose three devices to compare: a meconium aspirator (Neotech Products Inc, Chatsworth, Calif), a hand pump (Res-Q-Vac, Repromed Systems Inc, New York, NY), and a 10F suction catheter (Superior Healthcare Group Inc, Cumberland, RI). Both the meconium aspirator and the hand pump were used with a 3.0-mm endotracheal tube. INTERVENTION: We instilled 0.8 mL of a homogeneous mixture of human meconium and saline (44 g of meconium per 100 mL of saline) in the trachea before applying each suction technique. The meconium aspirator and the suction catheter were each evaluated at three different vacuum pressures, -40, -80, and -150 mm Hg, using both continuous and interrupted suction. The hand pump was evaluated with one and two activations (one activation generates -100 cm H2O, according to the manufacturer). MEASUREMENTS AND RESULTS: The percentage of instilled meconium recovered was consistently greatest (P less than .001) with the meconium aspirator (mean, 88.9% at -150 mm Hg, 84.9% at -80 mm Hg, and 73.5% at -40 mm Hg), intermediate with the catheter (mean, 81.0% at -150 mm Hg, 73.2% at -80 mm Hg, and 67.5% at -40 mm Hg), and least for the hand pump (mean, 67.9% with one activation and 72.6% with two activations). Recovery was better with continuous suction (P = .02) and increasing pressure (P less than .001). CONCLUSIONS: Among the techniques compared, the meconium aspirator at -150 mm Hg, using continuous suction, performed best in this model. It is unknown, however, to what extent the tracheal mucosa may be affected by this degree of negative pressure.

Animals↗