morphine and Airway-Obstruction

Although meconium ileus (MI) is the earliest manifestation of cystic fibrosis (CF), and is associated with poorer growth, the longitudinal pulmonary progression of CF children with MI is not clear. To test the hypothesis that MI is associated with worse pulmonary outcomes, we prospectively compared from diagnosis to 12 years of age 32 CF children with MI to 50 CF children without MI who were diagnosed during early infancy through neonatal screening. Pulmonary outcome measures included respiratory symptoms, respiratory infections, pathogens, antibiotic usage, hospitalizations, quantitative chest radiology, spirometry, and lung volume determinations. Obstructive lung disease was defined as percent predicted spirometry values below the lower limits of normal. Longitudinal analyses revealed no significant differences in cough, wheezing, respiratory infections, prevalence of and median times to acquisition of Pseudomonas aeruginosa or Staphylococcus aureus, antibiotic usage, and chest radiograph scores between the two groups. However, MI children showed significantly worse forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), forced expiratory flow between 25-75% of FVC (FEF(25-75)), % predicted FEV(1), % predicted FEF(25-75), and total lung capacity (TLC). These differences were particularly apparent beginning at age 8-10 years. MI children also had higher rates of and shorter median times to obstructive lung disease. Subgroup analyses showed MI children treated surgically and those treated medically had similar pulmonary outcomes. In conclusion, MI children have worse lung function and more obstructive lung disease than those without MI. Such abnormalities are accompanied by reduced lung volume. MI is a distinct CF phenotype with more severe pulmonary dysfunction.

Topics: Airway Obstruction; Cystic Fibrosis; Female; Humans; Ileus; Infant; Infant, Newborn; Lung; Lung Diseases; Male; Meconium; Neonatal Screening; Prognosis; Prospective Studies; Respiratory Function Tests; Time Factors; Wisconsin

Topics: Airway Obstruction; Humans; Infant, Newborn; Meconium; Persistent Fetal Circulation Syndrome

In order to define as effective a procedure as possible for the intra- and post-partum clearance of the upper airways of meconium contaminated infants, three methods of suction clearance, nasal, oral and combined nasal and oral, were carried out on each of five kittens aged between 17 to 19 weeks. There was an interval of at least one week between each investigation. The animals were anaesthetized with ketamine intramuscularly. The pressure changes during delivery were simulated using a compressed blood pressure cuff around the kittens thorax. During the first minute of thoracic compression Tc 99 labeled synthetic sputum was introduced into both the oro- and nasopharynx, then during the 2nd minute the instilled fluid was removed using a conventional extractor with mucus trap. Solely oral or solely nasal routes were used, suction was carried out for 60 secs, whereas when the combined technique was applied the oral and nasal cavities were cleared for only 30 secs each. At the end at the 2nd minute thoracic compression was released and a deep inspiration occurred. After five minutes the radioactivity remaining after suction was documented using a gamma-camera. We attempted to answer the following questions: How much mucus could be extracted with each different method, and where the remaining amount was later distributed? Nasal suction alone was found to be inefficient; using this route an average of 13% (only an eight of the amount instilled) could be removed. Oral suction led to the recovery of an average of 52% of the material instilled, the combined technique much as 56%. After re-establishment of spontaneous respiration, it could be clearly seen that, independent of the efficacy of the technique used, the majority of the remaining radioactivity (55 relative percent) is localized in the head and neck area. Absolute values are 45% for nasal suction, 26% for oral, and 24% for the combined oro-nasal route. The other part of the remaining radioactivity was found in the lung or in the stomach. It must be pointed out that the aspirate need not be disturbed in both of the parts, both the stomach and the lungs can be solely involved. Five minutes after spontaneous respiration had been resumed the lungs revealed only a centrally distributed radioactivity. This corresponds anatomically to the trachea and major bronchi. The peripheral area of the lungs was free of aspirate at this point in time.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Airway Obstruction; Amniotic Fluid; Animals; Cats; Disease Models, Animal; Humans; Infant, Newborn; Inhalation; Meconium; Respiration; Suction

The long-term outcome of infants subjected to perinatal asphyxia can be improved if they are recognized as high risk before birth and managed so as to reduce the period of hypoxemia to a minimum. Prompt and effective resuscitation of asphyxiated infants at the time of birth can contribute much to improving the long-term outcome of these infants.

Topics: Airway Obstruction; Apgar Score; Asphyxia Neonatorum; Congenital Abnormalities; Female; Fetal Distress; Fetal Hypoxia; Humans; Infant, Newborn; Intensive Care Units, Neonatal; Meconium; Pregnancy; Pregnancy Complications; Respiratory Distress Syndrome, Newborn; Resuscitation

MAS can be divided into 2 stages, distinguishable with respect to morphology of the lungs, clinical symptoms and laboratory data. The reason for the vasoconstriction of the pulmonary vascular bed typical for stage 2 is not yet fully understood. It seems, however, plausible that meconium contains substances (enzymes?) which may trigger the release or the synthesis of vasoactive compounds during the process of an aseptic inflammation. Cleaning the upper respiratory tract of an infant with meconium in the amniotic fluid immediately after birth is the most effective step in the prevention of MAS. This measure has led to a dramatic decline in both morbitity and mortality of the disease. In rare instances rinsing of the trachea with saline can help to remove considerable amounts of meconium too thick and sticky to be removed by simple suction.

Topics: Airway Obstruction; Animals; Humans; Hypoxia; Infant, Newborn; Infant, Newborn, Diseases; Inhalation; Lung; Meconium; Mediastinal Emphysema; Partial Pressure; Pneumothorax; Pulmonary Emphysema; Rabbits; Radiography; Respiration; Respiration, Artificial; Syndrome; Therapeutic Irrigation

Topics: Airway Obstruction; Humans; Infant, Newborn; Meconium; Suction

To compare the efficacy of bulb and catheter suctioning of upper airway meconium in neonates, meconium labeled with technetium Tc 99m sulfur colloid was injected into the trachea and oropharynx of anesthetized kittens. Human birth conditions were simulated by an inflated blood pressure cuff around the thorax and abdomen of the animals and by partial degassing of the lungs before introduction of meconium. Distribution of meconium in the upper airway was determined by scintigraph. Catheter suction brought about a 43% decrease in radioactivity while there was only a 1% decrease after bulb suctioning. Meconium may persist in the trachea for more than 20 minutes after introduction, indicating the desirability of continued suctioning efforts in neonates with meconium aspiration syndrome. The relative safety of the two techniques was not assessed.

Topics: Airway Obstruction; Animals; Catheterization; Cats; Female; Humans; Infant, Newborn; Infant, Newborn, Diseases; Meconium; Pneumonia, Aspiration; Suction; Syndrome

The relationship between pulmonary function and the migration of meconium to distal airways was determined in 10 rabbits (mean weight 2.6 kg) after insufflation of a meconium-saline mixture (1--2 ml/kg). Animals were anesthetized, cannulated, intubated, and mechanically ventilated with 100% oxygen. Lung mechanical dysfunction was most severe during the early phase of meconium migration, 15 min postinsufflation. Substantial increases in inspiratory lung resistance (RI) and expiratory lung resistance (RE) suggest that the site of obstruction at 15 min was the large airways. A decrease in dynamic lung compliance with unchanged static compliance characterizes the obstruction as partial. At 15 min and throughout the migration process, RE was greater than RI, demonstrating a check-valve effect. This phenomenon was substantiated by an increased functional residual capacity (FRC) in all rabbits, presumably due to gas trapping. Secondary to these changes, marked hypoxemia, hypercapnea, and acidosis developed in spite of assisted ventilation with 100% oxygen. At 60 and 120 min postinsufflation, both RI and RE decreased as compared to 15 min. This suggests that the predominant site of obstruction shifted to medium and small airways concomitant with the migration of meconium. Widespread and uneven distribution of meconium still produced significant frequency dependence of lung compliance. Static compliance remained unchanged, indicating that meconium does not affect surface-active or tissue properties of the lung within 120 min postinsufflation. These data suggest that effective respiratory management after meconium aspiration is dependent on the degree of meconium migration, as reflected by pulmonary mechanics.

Topics: Airway Obstruction; Airway Resistance; Animals; Inhalation; Lung; Lung Compliance; Meconium; Rabbits; Respiration

Aspiration of meconium by the fetus at or near delivery may be associated with high infant morbidity and mortality. The meconium aspiration syndrome (MAS) is often preventable, yet cases of MAS continue to occur. This paper describes the pathophysiology of MAS. The development of MAS involves passage of meconium by a compromised fetus and the subsequent aspiration of that meconium. Respiratory tract obstruction, hypoxia, hypercapnia, and acidosis may all result. Treatment of MAS is primarily supportive, and high mortality rates have been reported with the more severe cases. There is good evidence that careful suctioning of the infant's upper respiratory tract can in most cases prevent MAS. The suctioning, performed while the infant's head is still on the mother's perineum and prior to the first inspirations, is both a safe and effective preventive procedure.

Topics: Airway Obstruction; Female; Fetal Hypoxia; Fetus; Gastrointestinal Motility; Humans; Infant, Newborn; Meconium; Pneumonia, Aspiration; Pregnancy; Respiratory Insufficiency; Respiratory System; Suction; Syndrome

Topics: Adult; Airway Obstruction; Female; Humans; Infant, Newborn; Infant, Newborn, Diseases; Meconium; Pneumonia, Aspiration; Pregnancy

Topics: Adolescent; Adult; Airway Obstruction; Child; Child, Preschool; Cystic Fibrosis; Female; Humans; Infant; Infant, Newborn; Infertility; Intestinal Obstruction; Liver; Lung; Male; Meconium; Middle Aged; Pancreas; Respiratory Tract Infections

We investigated the effects of meconium on the lungs of an adult rabbit model to distinguish between mechanical obstruction of airways and chemical pneumonitis. After the rabbits were anesthetized and intubated, 20% human meconium in saline was instilled into the trachea. Arterial and mixed venous blood gases, functional residual capacity, cardiac output vascular pressures, calculated venous admixture, and pulmonary vascular resistance were measured. Sections of affected lung tissue were examined microscopically. The results were consistent with an early mechanical obstruction of airways with gradual development of chemical pneumonitis over 48 hours.

Topics: Airway Obstruction; Animals; Carbon Dioxide; Functional Residual Capacity; Inhalation; Lung; Meconium; Oxygen; Partial Pressure; Pneumonia; Pulmonary Atelectasis; Rabbits

Topics: Airway Obstruction; Female; Humans; Infant, Newborn; Infant, Newborn, Diseases; Male; Meconium; Suction; Trachea

Topics: Airway Obstruction; Asphyxia Neonatorum; Humans; Infant, Newborn; Infant, Newborn, Diseases; Meconium; Resuscitation