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Biomedical subjects

M C Walsh

Publications and source records attributed to M C Walsh.

11 recordsLinked to original sources
PubMed1989

Accidental carbadox overdosage in pigs in an Irish weaner-producing herd.

A weaner ration containing carbadox at concentrations of 331 to 363 mg/kg was accidentally fed to suckling and weaned pigs in an 84 sow herd. Discarded ration was fed to 36 sows. One hundred and sixty five weaner pigs died in a 10 week period with clinical signs including refusal to eat, ill thrift, the passing of hard pelleted faeces, posterior paresis and death in seven to nine days. The surviving weaners did not thrive and some males showed poor testicular development. Sows and suckling pigs that consumed the ration also failed to thrive as did the progeny of affected sows. The main pathological finding was obliteration of the zona glomerulosa of the adrenal cortex. Increased potassium and decreased sodium concentrations in serum were the most notable and consistent biochemical findings.

Animal Feed↗
PubMed1989

High-frequency jet ventilation in neonatal pulmonary hypertension.

To determine if high-frequency jet ventilation is beneficial in neonates with persistent pulmonary hypertension, we compared the ventilator settings, blood gas concentrations, and outcome of infants who met established criteria for a high predictive mortality. During a six-year period, 14 neonates who had severe respiratory failure and hypoxemia while receiving conventional ventilation were treated with high-frequency jet ventilation. Twenty-three comparable infants meeting the same criteria were treated exclusively with conventional ventilation. After initiation of high-frequency jet ventilation there was a significant reduction in mean airway pressure and partial pressure of arterial carbon dioxide (PaCO2). In contrast, neonates treated exclusively with conventional ventilation continued to have higher airway pressures and PaCO2. However, there was no difference in the alveolar-to-arterial oxygen gradient, air leakage, incidence of bronchopulmonary dysplasia, or duration of assisted ventilation or oxygen supplementation. Furthermore, mortality was comparable in both groups of infants. These preliminary observations suggest that high-frequency jet ventilation can reduce airway pressure and PaCO2 in neonates with persistent pulmonary hypertension but does not appear to improve outcome.

Carbon Dioxide↗
PubMed1989

Determinants of gas flow through a bronchopleural fistula.

To assess the determinants of bronchopleural fistula (BPF) flow, we used a surgically created BPF to study 15 anesthetized intubated mechanically ventilated New Zealand White rabbits. Mean airway pressure and intrathoracic pressure were evaluated independently. Mean airway pressure was varied (8, 10, or 12 cmH2O) by independent manipulations of either peak inspiratory pressure, positive end-expiratory pressure, or inspiratory time. Intrathoracic pressure was varied from 0 to -40 cmH2O. BPF flow varied directly with mean airway pressure (P less than 0.001). However, at constant mean airway pressure, BPF flow was not influenced independently by changes in peak inspiratory pressure, positive end-expiratory pressure, or inspiratory time. Resistance of the BPF increased as intrathoracic pressure became more negative. Despite increased resistance, BPF flow also increased. BPF resistance was constant over the range of mean airway (P less than 0.01) pressures investigated. Our data document the influence of mean airway pressure and intrathoracic pressure on BPF flow and suggest that manipulations which reduce transpulmonary pressure will decrease BPF flow.

Airway Resistance↗
PubMed1989

Severity of necrotizing enterocolitis: influence on outcome at 2 years of age.

The long-term outcome of very low birth weight (VLBW) infants with necrotizing enterocolitis has been reported to be similar to that of other VLBW infants. To examine the influence of disease severity on outcome, the growth and neurodevelopment of survivors of necrotizing enterocolitis were evaluated when the babies were 20 months' corrected age. Between 1975 and 1983, 1506 VLBW infants were admitted to the hospital, and necrotizing enterocolitis developed in 84 (5.6%). Forty infants (48%) survived to be 20 months' corrected age, and complete follow-up data were available for 36. Survivors were classified by modified Bell's criteria into four groups by increasing severity of disease; 13 had mild necrotizing enterocolitis (stage IIA, IIB), and 23 had severe necrotizing enterocolitis (stage IIIA, IIIB). The 36 survivors were compared with 766 surviving VLBW infants without necrotizing enterocolitis. There were no perinatal or socioeconomic differences between groups. Compared with infants with stage II necrotizing enterocolitis at 20 months, infants with stage III necrotizing enterocolitis had a higher rate of subnormal body weight (39% vs 15%) and subnormal head circumference (30% vs 0%). Thirty-three percent of necrotizing enterocolitis survivors had significant neurodevelopmental impairment; the majority of impaired infants (10 of 12) were survivors of stage III necrotizing enterocolitis. These findings highlight the importance of continued evaluations for medical and neurodevelopmental sequelae.

Child Development↗
PubMed1988

Sustained inflation during HFOV improves pulmonary mechanics and oxygenation.

Effective use of high-frequency oscillatory ventilation (HFOV) may require maintenance of adequate lung volume to optimize gas exchange. To determine the impact of inflation during HFOV, sustained inflation was applied at pressures of 5, 10, and 15 cmH2O above mean airway pressure for 3, 10, and 30 s to 15 intubated, paralyzed, anesthetized rabbits after saline lavage to induce surfactant deficiency. Arterial blood gases were recorded in all rabbits while static compliance, resistance, time constant, and changes in functional residual capacity were recorded using the interrupter technique and plethysmograph in seven rabbits. Parameters were recorded before and 2 min after sustained inflation. Arterial PO2, compliance of the respiratory system, and functional residual capacity increased after sustained inflation at pressure levels of at least 10 cmH2O and 10-s duration. As the presence or duration of a sustained inflation was increased, oxygenation improved (P less than or equal to 0.01), but arterial PCO2 increased as longer sustained inflations were used (P less than or equal to 0.005). Sustained inflations of 5 cmH2O above mean airway pressure or of 3-s duration were ineffective. We conclude that either a critical pressure or duration of sustained inflation is needed to improve oxygenation and pulmonary mechanics during HFOV.

Animals↗
PubMed1987

The incidence of meningitis in neonates with necrotizing enterocolitis.

Although meningitis is common among patients with neonatal sepsis, review of the literature on necrotizing enterocolitis (NEC) reveals a paucity of information on the association of NEC and meningitis. We report four patients who had meningitis during the course of illness among 238 patients with documented NEC. We recommend that all patients with suspected NEC have a lumbar puncture as part of the diagnostic work-up, as meningitis may require different and prolonged therapy, and will necessitate more specific follow-up for neurodevelopmental problems.

Enterocolitis, Pseudomembranous↗
PubMed1987

Relationship of pulse oximetry to arterial oxygen tension in infants.

Pulse oximetry is a useful technique for noninvasive oxygen monitoring in sick infants. We simultaneously measured oxygen saturation by pulse oximetry and on arterial blood samples by co-oximetry as well as PaO2 and the relative content of fetal (F) and adult hemoglobin in order to evaluate the reliability of pulse oximetry. Comparisons were made in triplicate in ten infants with acute cardiorespiratory disease less than 7 days of age and in 11 infants with chronic lung disease greater than 28 days of age. Oxygen saturation pulse oximetry and arterial saturation were well correlated over a wide range of saturation values. In infants with chronic lung disease, PO2 derived from pulse oximetry was within 10 torr of measured PaO2 in 73% of comparisons. In contrast, calculated PaO2 was within 10 torr of measured PaO2 in only 50% of comparisons in patients with acute disorders. The chronic infants all had less than 10% hemoglobin F, but in the acute infants, hemoglobin F ranged from 26% to 83%. Nonetheless, correction of oxygen dissociation curves for type of hemoglobin in these acute infants failed to improve the correlation between calculated and measured PaO2. We conclude that pulse oximetry saturations and their derived PaO2 values correlated well with measured arterial saturation and PaO2 obtained from arterial blood samples in neonates with chronic lung disease and prolonged oxygen dependence. In infants with acute cardiorespiratory problems, pulse oximetry unreliably reflects PaO2, but may be useful in detecting clinical deterioration.

Evaluation Studies as Topic↗
PubMed1986

Necrotizing enterocolitis: treatment based on staging criteria.

Neonatal necrotizing enterocolitis is the most important cause of acquired gastrointestinal morbidity or mortality among low birthweight infants. Prematurity alone is probably the only identifiable risk factor. Although the etiology is unknown NEC has many similarities to an infectious disease. Proper staging helps improve reporting and the management of NEC.

Anti-Bacterial Agents↗