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Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Equipment has been developed for the servo-control of arterial oxygen tension in sick, newborn babies. Using an indwelling umbilical arterial oxygen electrode as sensor, the equipment successfully regulated the administration of oxygen to 12 newborn babies with respiratory distress syndrome, significantly improving the stability of arterial oxygen tension and lessening the duration of episodes of hypoxia and hyperoxia.
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PMID:New technique for servo-control of arterial oxygen tension in preterm infants. 45 11

Hyperoxia has been shown to enhance the toxicity of the herbicide paraquat. Experiments were conducted to learn more about the effects of oxygen following acute poisoning with paraquat as well as the structurally related herbicide, diquat. Rats were injected intravenously with various doses of diquat or paraquat and placed into an atmosphere of either 100% oxygen or room air. The time required for 50% lethality (LT50) of both diquat and paraquat was greatly diminished by hyperoxia and was dependent upon the herbicide dosage. Rats treated with 40 or 80 mg/kg diquat and exposed to 100% oxygen had a shorter LT50 than those treated similarly with paraquat. A dose of 20 mg/kg was equitoxic in 100% oxygen while rats treated with 5 or 10 mg/kg diquat had a longer LT50 than rats treated with the same dose of paraquat. All animals exhibited severe respiratory distress terminally. The plasma concentrations and tissue distribution of either herbicide at 20 mg/kg were the same in oxygen and air exposed animals. When oxygen concentrations were varied between 100% and 60% rats treated with 20 mg/kg diquat or paraquat exhibited increasing but equal LT50's. In 40% oxygen diquat treated rats died more rapidly than paraquat treated rats. These data demonstrate a toxic interaction between hyperoxia and diquat as well as paraquat.
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PMID:The influence of hyperoxia on the acute toxicity of paraquat and diquat. 54 May 39

Neonatal rats (4--7 days old) and adult rats (approximately 80 days old) were continuously exposed to either 96--98% oxygen or air. Examination of the lungs of neonatal rats, who survived 5 days of oxygen exposure with no evidence of respiratory distress, showed significant increases in the pulmonary superoxide dismutase (SOD) activity (peak value: 144% of air-exposed controls), glutathione peroxidase (GP) activity (126%), glutathione reductase (GR) activity (122%), reduced glutathione (GSH) level (176%), and glucose-6-phosphate dehydrogenase activity (151%). Adult rats, most of whom succumbed within 3 days of oxygen exposure, did not show any significant increase in the activities of pulmonary SOD, GP, GR, and the level of GSH as compared to the air-exposed adult animals. Glucose-6-phosphate dehydrogenase was significantly elevated in the 72-hr oxygen-exposed adult rats. It is concluded that increases in the lung complement of SOD, GR, GP, and GSH in the neonatal rat during oxygen challenge may provide the mechanism(s) for their increased tolerance to hyperoxia-induced lung injury as compared to the adults.
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PMID:Oxygen toxicity: comparison of lung biochemical responses in neonatal and adult rats. 64 79

Continuous positive airways pressure treatment by a face chamber in idiopathic respiratory distress syndrome. During a 3-year period 45 infants with idiopathic respiratory distress syndrome (IRDS) requiring ventilatory support were treated in the neonatal unit. Continuous positive airways pressure (CPAP) via the face chamber was applied as initial therapy in 39 infants and during weaning from initial intermittent positive pressure ventilation (IPPV) treatment in 5 infants, whereas 1 infant received IPPV only. Among the 39 infants initially treated with CPAP 9 required IPPV as well. The overall survival rate was 37/45 or 82%. Incapacity to hyperoxygenate while breathing 100% oxygen was the indication for CPAP while occurrence of apnoeic attacks was the indication for IPPV. Pao2 during the hyperoxia test before ventilatory support was less than 50 mmHg in 10 infants and between 50 and 105 mmHg in 35 infants. Surviving infants were followed up with neurological and developmental control examinations as well as chest x-ray, and in several infants pulmonary function tests. 3/37 infants had moderate neurological sequelae and only 1/37 infants developed bronchopulmonary dysplasia. No deleterious effects of the face chamber were seen. As the face chamber is a noninvasive and easily applied technique for CPAP therapy without hazards, it is proposed that it should be used at a still earlier stage of IRDS in order to lesson the need for IPPV treatment and to increase the neurological and lung functional quality of survival.
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PMID:Continuous postive airways pressure treatment by a face chamber in idiopathic respiratory distress syndrome. 78 73

Infants with the idiopathic respiratory distress syndrome admitted to the intensive care unit during January 1972 to September 1974 were reviewed. The overall mortality rate for infants whose birth weight was 1000 g or more was under 10%, and for those who established spontaneous respiration after birth it was less than 5%. The hyperoxia test was not a useful guide to prognosis. It was possible on the basis of the infants' ability to establish spontaneous ventilation after birth to divide them into two groups. In those who established adequate ventilation the mortality rate was 4-5%; in those who did not it was 57%. This test should be generally applied, since not only does it give an immediate guide to the severity of the disease, which is better than that provided by birth weight, gestational age, or the hyperoxia test, but it may be applied to infants born in and outside a hospital providing neonatal intensive care. Improvement in the outlook for infants with a bad prognosis will be achieved only by improvements in perinatal care designed to minimize severe intrapartum asphyxia in infants of low birth weight.
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PMID:Prognosis for infants with idiopathic respiratory distress syndrome. 109 44

Pulmonary superoxide dismutase (SOD) acitivity was determined for various groups of human fetuses, infants, and adults. Enzyme activity was found to increase with age from a low of 17 +/- 1 units/mg DNA in fetal lung to 49 +/- 6 units/mg DNA in infant lung and finally to 110.2 +/- 14.8 units/mg DNA in adult lung (P less than 0.05). No difference in lung SOD activity was demonstrated between normal infants and those with idiopathic respiratory distress/hyaline membrane disease (IRDS/HMD). No significant differences in SOD activity were found among all the samples of infant blood. Adult blood samples, however, contained significantly greater SOD activity both in terms of heme concentration and volume of whole blood (P less than 0.05). SOD activity in lung tissue from both rats and rabbits were also found to increase with age from a low value in fetal animals to a maximum activity in adults (P less than 0.05). Exposure of New Zealand White rabbits, prematurely delivered by caesarian section, to 80% oxygen for 24 hr resulted in a 42% increase in lung SOD activity. Similarly, 7-day-old Sprague-Dawley rats exposed to 85% oxygen for 24 hr showed a 43% increase in pulmonary SOD activity. No increase in pulmonary SOD was observed when adult rats were exposed to 85% oxygen for 24 hr. The effect of hyperoxia on SOD activity in excised lung was investigated. Rat lung, incubated in either heparinized whole blood or in plasma and exposed to 100% oxygen, showed a 30% increase in SOD activity after 2 hr. This capacity of lung tissue to respond to hyperoxia in vitro with increased SOD activity was age dependent. The maximum increase in SOD activity was seen with lungs from 10-12-day-old rats. The oxygen-stimulated increase in lung SOD activity disappeared at about 19-20 days of age.
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PMID:Developmental characteristics of pulmonary superoxide dismutase: relationship to idiopathic respiratory distress syndrome. 125 Jun 44

Persistent pulmonary hypertension of the newborn (PPHN) characterised by right to left shunting with intense cyanosis is difficult to manage, and in the best of centres carries a 40-60 percent mortality. We report our one year's experience of managing six neonates with PPHN. There were 5 males and 1 female with mean birth weight of 2.59 +/- 0.487 kg and gestation period 39 +/- 2.0 wks and 1 minute Apgar score 2.8 +/- 2.1. Four to six babies were born by cesarean section and 3-6 babies had aspiration pneumonia. All babies presented within 12 hours of age (mean 5.08 +/- 5 hrs) with intense cyanosis and respiratory distress. Diagnosis were confirmed in all by (a) hyperoxia test, (b) simultaneous determination of preductal and postductal paO2 (c) contrast echocardiography and (d) hyperoxia-hyperventilation test. Babies were managed with hyperventilation using mean ventilatory rates of 100 +/- 45 per minute, an inspired oxygen concentration of 100%, peak inspiratory pressures 27 +/- 9 cm of H2O, and expiratory pressures 5 +/- 1.6 cms of H2O, and mean air way pressures of 10.4 +/- 2.7 cms H2O. Alkali therapy was used in 3 of the six babies whereas low dose dopamine was infused in all six babies. Inspite of aggressive ventilatory therapy, only 3 out of 6 babies could be salvaged.
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PMID:Persistent pulmonary arterial hypertension of the newborn. 134 Aug 63

To test the hypothesis that administration of allopurinol could modify the response to prolonged hyperoxia in premature baboons (140 days gestation) with respiratory distress syndrome, we evaluated physiological, pathological, and lung biochemical parameters in groups of premature baboons treated with mechanical ventilation and exposed to various amounts of oxygen for 6 days. Three groups of experimental animals were studied, including animals that received oxygen as needed to maintain arterial oxygen between 60 and 80 Torr [inspiratory O2 concentration- (FIO2) PRN], animals that received 100% oxygen continuously but also received allopurinol intravenously at a dose of 10 mg.kg-1.day-1 (FIO2-1.0 + allopurinol), and animals that received 100% oxygen continuously and the vehicle for allopurinol administration (FIO2-1.0). Pathological examinations of the experimental animals showed evidence of lung injury in both 100% oxygen-exposed groups, but the allopurinol-treated animals had findings more compatible with the FIO2-PRN group, with relatively few macrophages or polymorphonuclear lymphocytes being present in lung tissue. Lungs of animals treated with allopurinol were also more distensible and had a trend toward decreased lung water compared with the FIO2-1.0 group. Allopurinol-treated animals were able to induce lung glutathione concentrations and glutathione-related and antioxidant enzyme activities compared with the normoxic control (FIO2-PRN) group. Ventilator pressure requirements were also decreased in the allopurinol-treated animals compared with the FIO2-1.0 controls after 42 h. These data suggest that treatment of hyperoxia-exposed premature baboons with allopurinol for the first 6 days of life results in significant changes in lung responses and antioxidant defenses compared with vehicle-treated baboons exposed to 100% oxygen for the same time period.
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PMID:Allopurinol-induced effects in premature baboons with respiratory distress syndrome. 203 82

Injury to the capillary endothelium and to alveolar epithelial cells of the lung may result in damage to the underlying collagen of the extracellular matrix. To examine this possibility, whole body irradiation, bleomycin injections, and exposure to hyperoxia were used to induce various types of lung damage in mice. The morphology of the lung and the cellular and protein content of bronchoalveolar lavage fluid were used to assess injury. Collagen breakdown was assessed from the hydroxyproline concentrations in bronchoalveolar lavage fluid. When lung cell injury was observed, protein leaked in to alveoli and hydroxyproline was detected in bronchoalveolar lavage fluid. An increase in hydroxyproline followed endothelial damage by irradiation and was greatly increased when type 1 epithelial cell necrosis also occurred after bleomycin injection or hyperoxia. Maximal concentrations of hydroxyproline occurred in mice showing respiratory distress after six days of hyperoxia. Concentrations returned to zero during the subsequent phases of cell regeneration and fibrosis seen after bleomycin injection and irradiation. There was little change in the cellular components of bronchoalveolar lavage fluid at any time. The results indicate that collagen breakdown occurs during acute lung injury and can be quantified in terms of the hydroxyproline concentration in lavage fluid. Such a change in the extracellular matrix might influence the subsequent division and differentiation of regenerating cells during repair.
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PMID:Collagen breakdown during acute lung injury. 246 95

Extracorporeal membrane oxygenation (ECMO) provides lung rest for moribund infants with congenital diaphragmatic hernia (CDH) after deterioration from a "honeymoon" period. This suggests that unstable pulmonary hypertension determines demise more than pulmonary hypoplasia. We avoided treating overwhelming pulmonary hypoplasia by using ECMO only if the premoribund condition had been marked by evidence of adequate lung parenchyma as a best preductal PO2 greater than 100 torr and PCO2 less than 50 torr with maximal therapy. Twenty-six CDH infants with respiratory distress within 4 hours survived operation. Five were not ECMO candidates, with best PO2 33 +/- 9, PCO2 157 +/- 30 torr, and died. Seven honeymoon infants, with best PO2 325 +/- 80, PCO2 27 +/- 5, survived without ECMO. Fourteen additional infants had honeymoon 26 +/- 13 hours with PO2 256 +/- 48, PCO2 30 +/- 8 followed by a-AdO2 gradients 600 torr x 16 +/- 4.5 hours despite maximal therapy. All 14 were treated with ECMO for 48 to 210 hours. Arterial blood gas values at initiation were PO2 34 +/- 6, PCO2 59 +/- 19, and pH 7.22 +/- 0.2. Right-to-left shunting due to pulmonary hypertension was documented by oximetry and two-dimensional echo/Doppler examination. Twelve of 14 (86%) ECMO-treated infants survived with normal arterial blood gas values on room air, no right-to-left shunting, and no gross neurologic sequellae to date. Two of 14 died. Improvement on ECMO was marked by positive hyperoxia response and decreased right-to-left shunting.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Selective use of extracorporeal membrane oxygenation in the management of congenital diaphragmatic hernia. 312 55


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