Congenital Vertebral Malformation in a Neonatal Elk (Cervus canadensis) in Kentucky, USA.

We captured a <1-d-old male elk calf (Cervus canadensis) with a shortened neck. Postmortem examination revealed trauma, meconium aspiration syndrome, and cervical vertebral malformation (partial fusion and narrowed disc spaces). This observation is novel in a wild elk calf, although the gross lesions resembled complex vertebral malformation in neonatal cattle.

Tracheal suctioning improves gas exchange but not hemodynamics in asphyxiated lambs with meconium aspiration.

BACKGROUND: Current neonatal resuscitation guidelines recommend tracheal suctioning of nonvigorous neonates born through meconium-stained amniotic fluid. METHODS: We evaluated the effect of tracheal suctioning at birth in 29 lambs with asphyxia induced by cord occlusion and meconium aspiration during gasping. RESULTS: Tracheal suctioning at birth (n = 15) decreased amount of meconium in distal airways (53 ± 29 particles/mm(2) lung area) compared to no suction (499 ± 109 particles/mm(2); n = 14; P < 0.001). Three lambs in the suction group had cardiac arrest during suctioning, requiring chest compressions and epinephrine. Onset of ventilation was delayed in the suction group (146 ± 11 vs. 47 ± 3 s in no-suction group; P = 0.005). There was no difference in pulmonary blood flow, carotid blood flow, and pulmonary or systemic blood pressure between the two groups. Left atrial pressure was significantly higher in the suction group. Tracheal suctioning resulted in higher Pao2/FiO2 levels (122 ± 21 vs. 78 ± 10 mm Hg) and ventilator efficiency index (0.3 ± 0.05 vs.0.16 ± 0.03). Two lambs in the no-suction group required inhaled nitric oxide. Lung 3-nitrotyrosine levels were higher in the suction group (0.65 ± 0.03 ng/µg protein) compared with the no-suction group (0.47 ± 0.06). CONCLUSION: Tracheal suctioning improves oxygenation and ventilation. Suctioning does not improve pulmonary/systemic hemodynamics or oxidative stress in an ovine model of acute meconium aspiration with asphyxia.

Albumin lavage does not improve the outcome of meconium aspiration syndrome.

OBJECTIVE: Meconium aspiration syndrome is still a serious condition with high mortality and morbidity. No specific treatment is yet available, although surfactant is known to reduce the need for extracorporeal membrane oxygenation and surfactant lavage has shown promising results in animal studies. Our group has previously shown reduced oxygenation index in an experimental model of meconium aspiration syndrome in newborn pigs when mixing albumin with meconium before endotracheal instillation. Lung compliance increased when albumin was instilled after meconium as a rescue. The aim of this study was to combine the effect of albumin and lavage. METHODS: Sixteen newborn pigs (six in the meconium-albumin group, six in the meconium group, and four control animals) were anesthetized and tracheotomized. Meconium 4 mL/kg was instilled endotracheally. After five minutes, albumin 15 mL/kg was instilled in the meconium-albumin group followed by endotracheal suctioning. The observation time was six hours. Respiratory and hemodynamic parameters were measured. The terminal complement complex and proinflammatory cytokines were analyzed in plasma. RESULTS: Oxygenation index, ventilatory index, and the terminal complement complex (sC5b-9) increased significantly in both groups, but significantly more in the meconium-albumin group. Compliance decreased, but significantly more in the meconium-albumin group. The terminal sC5b-9 complex increased in both groups, but significantly more in the meconium-albumin group. Tumor necrosis factor-alpha, interleukin (IL)- 1beta, and IL-6 increased significantly in both groups. CONCLUSION: Albumin-lavage did not improve the outcome of experimental meconium aspiration syndrome.

Morphological changes in the lungs of meconium-stained piglets.

Meconium staining of the skin is a common event associated with fetal hypoxia, stillbirths, weak-born piglets, and neonatal mortality. Aspiration of meconium leads to meconium aspiration syndrome (MAS). This study was undertaken to assess the relationship between the degree of meconium staining of the skin at birth, meconium aspiration, and pulmonary changes in porcine neonates. A total of 353 farrowing sows and 3,693 born piglets were monitored during parturition and for 15 days after delivery. Umbilical cords were classified as normal or ruptured. Meconium staining in the skin was graded as nonstained, mildly, moderately, and severely stained. Mortality from birth to 15 days of age was 8.4%. The lungs from 60 meconium-stained piglets and 60 lungs from nonstained piglets were collected and microscopically examined for meconium aspiration and inflammation. Rupture of the umbilical cord was significantly higher (P < 0.01) in meconium-stained piglets. Microscopically, 32% and 40% of the lungs had evidence of meconium for the stained and nonstained groups, respectively. The microscopic grade of meconium aspiration and inflammatory cells was not different between nonstained and meconium-stained piglets. Aspiration of meconium induced a granulomatous response in the lungs. It was concluded that the grade of meconium staining is a good indicator of fetal hypoxia, but not a good predictor for meconium aspiration and MAS in piglets.

Pulmonary inflammation associated with aspirated meconium and epithelial cells in calves.

"Meconium aspiration syndrome" is a condition resulting in respiratory distress and the occasional death of newborn human beings. A retrospective study was conducted on 52 calves that were submitted for postmortem examination to the Atlantic Veterinary College, Charlottetown, Prince Edward Island, Canada. These calves died of infectious and noninfectious diseases within the first 2 weeks of life due to a variety of causes. The most common cause of death was infectious enteric disease. Histologic examination of lungs revealed that 42.5% of calves had evidence of meconium, squamous cells, or keratin in the lung. There was considerable variation in the magnitude of histologic changes in lungs containing aspirated material. Typically, affected lungs had only a few inconspicuous pieces of meconium, keratin, and squamous cells within bronchoalveolar spaces. Sporadically, the entire lumen of airways was obliterated by aspirated material. Lungs with aspirated material had a mild but diffuse alveolitis characterized by exudation of a few neutrophils, macrophages, and occasional multinucleated giant cells. Obstruction of small airways and focal atelectasis were also observed. Similar lesions have been reported in human meconium aspiration syndrome. It is concluded that histologic changes similar to those of human meconium aspiration syndrome occur commonly in calves that die within 2 weeks of birth. Further studies involving healthy age-matched calves are required to evaluate the clinicopathologic significance of meconium aspiration in this species.