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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pulse oximetry is noninvasive, fast, and simple, making it a very popular way of assessing oxygenation in pediatric patients. However, there are few studies that establish the accuracy of this technology over a wide range of oxygen saturations in children. This study, done in 47 children aged from 1 day to 16 years with congenital heart disease and undergoing cardiac catheterization, compared the direct measurement of arterial oxygen saturation to values from pulse oximetry. Oxygen saturation was measured by an IL-282 Co-oximeter, which also measured carboxyhemoglobin and methemoglobin, and was compared to values obtained from both a Biox III and Nellcor N100. Both pusle oximeters gave values that closely correlated with the actual saturation (r = 0.91 and 0.93, respectively) with standard errors of the estimate of 4.1 and 3.2%, respectively. For both devices, the error increased with decreasing saturations, being progressively larger below a saturation of 80%. The difference between the actual saturation and that measured by pulse oximetry bore no relationship to the presence of carboxyhemoglobin, methemoglobin, fetal hemoglobin, bilirubin, cardiac index, or age of the patient. In conclusion, pulse oximetry, while a very useful technology in pediatrics, must be interpreted with some caution in children with severe cyanosis.
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PMID:Pulse oximetry versus measured arterial oxygen saturation: a comparison of the Nellcor N100 and the Biox III. 203 Sep 22

Inhaled nitric oxide is a specific pulmonary vasodilator. This study was undertaken to assess the effect on pulmonary arterial pressure of administering 100% oxygen compared with nitric oxide in oxygen. Thirteen mechanically ventilated children undergoing routine cardiac catheterization for the investigation of congenital heart disease were studied. Pulmonary arterial pressures were measured during inhalation of 30% oxygen (baseline), 100% oxygen, and nitric oxide (40 parts per million) in oxygen. In addition, in six children the pulmonary/systemic blood flow ratio and pulmonary vascular resistance were calculated using oxygen content, an assumed value for oxygen uptake, and the Fick principle. Results were compared using analysis of variance and the Wilcoxon signed-rank test. Pulmonary arterial pressure decreased from a mean value of 29.5 mmHg (SD 15.1) to 25.6 mmHg (SD 9.3), p = 0.048, after increasing the inspired oxygen fraction from 0.3 to 1.0. The addition of nitric oxide caused a further reduction to 22.9 mmHg (SD 7.9), p = 0.0001. There was no change in systemic arterial pressure or heart rate during the study period, but a small increase occurred in the mean methemoglobin level (1.1% to 1.3%) p = 0.039. Changes in the pulmonary/systemic blood flow ratio and pulmonary vascular resistance (n = 6) were not significant. Nitric oxide in oxygen appears to be a more potent pulmonary vasodilator than oxygen alone in pediatric patients with congenital cardiac defects.
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PMID:Effects of oxygen and nitric oxide in oxygen on pulmonary arterial pressures of children with congenital cardiac defects. 866 48

Inhaled nitric oxide, with a threshold of perhaps only a few parts per million, is a selective pulmonary vasodilator in patients with congenital heart disease and increased pulmonary vascular resistance. Multiple reports suggest that it may be useful in managing postoperative pulmonary hypertension in the cardiac patient, although it is unknown to what extent inhaled nitric oxide can actually reduce morbidity and mortality in this setting. This agent also holds promise for evaluating patients with pulmonary hypertension prior to heart transplantation. Although special care is needed to avoid toxicity related to excess inhaled nitric oxide or nitric dioxide or increased methemoglobin, the risk of complications with inhaled nitric oxide therapy appears to be very low. Inhaled nitric oxide will likely continue to play a significant role in the pre-and postoperative management of patients with congenital heart disease.
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PMID:Inhaled nitric oxide in the management of congenital heart disease. 866 35

Cyanosis is a physical finding that can occur at any age but presents the greatest challenge when it occurs in the newborn. The cause is multiple, and it usually represents an ominous sign, especially when it occurs in association with neonatal sepsis, cyanotic congenital heart disease, and airway abnormalities. Cyanosis caused by abnormal forms of hemoglobin can also be life-threatening, and early recognition is mandatory to prevent unnecessary investigations and delay in management. Abnormal hemoglobin, such as hemoglobin M, is traditionally discovered by electrophoresis, so the newborn screen, which is mandatory in several states, is a useful tool for the diagnosis. Although acquired methemoglobinemia, caused by environmental oxidizing agents, is common, congenital deficiency of the innate reducing enzyme is so rare that only a few cases are documented in the medical literature around the world. We present a neonate with cyanosis as a result of congenital deficiency of the reduced nicotinamide adenine dinucleotide-cytochrome b5 reductase enzyme. This infant was found to be blue at a routine newborn follow-up visit. Sepsis, structural congenital heart disease, prenatal administration, and ingestion of oxidant dyes were excluded as a cause of the cyanosis by history and appropriate tests. Chocolate discoloration of arterial blood provided a clue to the diagnosis. A normal newborn screen and hemoglobin electrophoresis made the diagnosis of hemoglobin M unlikely as the cause of the methemoglobinemia (Hb A 59.4%, A2 1.8%, and F 38.8%). Red blood cell enzyme activity and DNA analysis revealed a homozygous form of the cytochrome b5 reductase enzyme deficiency. He responded very well to daily methylene blue and ascorbic acid administration, and he has normal growth and developmental parameters, although he shows an exaggerated increase in his methemoglobin level with minor oxidant stress such as diarrhea.
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PMID:Congenital methemoglobinemia: a rare cause of cyanosis in the newborn--a case report. 1289 22

Recommendations by the US Department of Health and Human Services Secretary's Advisory Committee on Heritable Disorders in Newborns and Children aim to increase congenital heart disease screening by pulse oximetry in the nursery. Here, we describe a novel fetal methemoglobin variant discovered in a newborn found to have oxygen saturations significantly below normal upon pulse oximetry screening for congenital heart disease. As universal newborn screening with pulse oximetry is implemented, hereditary variant hemoglobins should be considered in the diagnostic work-up in otherwise well newborns with low SpO2 .
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PMID:Hemoglobin Shady Grove: a novel fetal methemoglobin variant. 2346 May 88

A 21-year-old pregnant female of known rheumatic heart disease presented to us for evaluation of central cyanosis during her late pregnancy. Though she was investigated for any associated congenital heart disease or pulmonary arteriovenous fistula, but incidentally she was diagnosed of having acquired methemoglobinemia. Her serum methemoglobin level was 33% which was far above the normal range. Ultimately, she was managed conservatively and delivered through elective caesarean section. Though the delivered baby was lethargic after birth, but later he was improved and discharged. This was the first case reported so far that a pregnant patient of rheumatic heart disease developed cyanosis due to methemoglobinemia.
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PMID:A patient with rheumatic heart disease presented with central cyanosis due to acquired methemoglobinemia during late pregnancy - A rare association. 2402 74

Congenital methemoglobinemia is a rare condition caused by cytochrome b5 reductase deficiency, cytochrome b5 deficiency, or hemoglobin M disease. Newborn pulse oximetry screening was developed for the early detection of critical congenital heart disease; however, it also enables the early identification of other hypoxemic conditions. We present the case of a term neonate who was admitted to the neonatal unit after a failed pulse oximetry screening at 3 hours of age. Oxygen saturations remained between 89% and 92% despite an increase in oxygen therapy. Chest radiograph and echocardiogram results were normal. A capillary blood gas test had normal results except for a raised methemoglobin level of 16%. Improvement was seen on the administration of methylene blue, which also resulted in an increase in oxygen saturations to within normal limits. Further investigation revealed evidence of type I hereditary cytochrome b5 reductase deficiency as a result of a CYB5R3 gene mutation with 2 pathogenic variants involving guanine-to-adenine substitutions. Although mild cyanosis is generally the only symptom of type I disease, patients may later develop associated symptoms, such as fatigue and shortness of breath. If an early diagnosis is missed, these patients are likely to present later with a diagnostic conundrum and be subject to extensive investigation. This case represents the success of pulse oximetry screening in the early identification of subclinical hypoxemia in this infant. After the exclusion of other pathologies, a routine investigation of capillary blood gas provided the information that led to a diagnosis, which allowed for early and effective management.
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PMID:Congenital Methemoglobinemia Identified by Pulse Oximetry Screening. 3073 39

Background: Methemoglobinemia (MET) should be suspected in cases where cyanosis is not associated with signs and symptoms of lung and/or heart disease, or in a cyanotic child exhibiting discrepancies in the partial pressure of oxygen in the arterial blood, the blood oxygen saturation, and the clinical assessment. Case presentation: A 10-month-old girl was taken to the Pediatric Emergency Department for the acute, sudden development of significant peroral cyanosis associated with gray pigmentation of the skin. The problem was evidenced approximately one hour after she ingested a homemade puree of mixed vegetables, mainly composed of potatoes and chards that had been prepared three days before and had been kept in the refrigerator since then. Physical examination revealed that the child was very pale, conscious, and without respiratory distress. Oxygen saturation of hemoglobin in the arterial blood (SpO2) was 94%. Respiratory, cardiovascular, and abdominal evaluations did not reveal any signs of disease. A venous blood sample showed chocolate-colored blood with a pH of 7.404, a partial pressure of CO2 (pCO2) of 40.6 mmHg, a partial pressure of oxygen (pO2) of 21.3 mmHg, a bicarbonate level of 24 mmol/L, and an oxygen saturation (SO2%) of 47.7%. CO-oximetry carried out simultaneously identified a methemoglobin level of 22%. MET was suspected, and oxygen via nasal cannula at a rate of 4 L/min was given with only a slight increase in oxygen saturation (96%). Slow intravenous injection of methylene blue 1 mg/kg over a period of 5 min was initiated. The peripheral oxygen saturation (SpO2) gradually improved to 100% over the next 20 min. Forty minutes later, venous blood gas analysis showed a methemoglobin level of 0.9% with a complete resolution of cyanosis; supplemental oxygen via nasal cannula was therefore discontinued. During the next 36 h, the patient remained hemodynamically stable with good oxygenation on room air. Conclusions: This case report shows that recognition of acquired MET in a child with sudden cyanosis onset requires a high index of suspicion. In daily activities, there is a need to pay particular attention when homemade vegetable soups for child alimentation are prepared. The consumption of vegetable soups must occur immediately after preparation. Storage in a refrigerator must last no more than 24 h and if longer storage is needed, vegetable soups should be frozen.
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PMID:The Dose Makes the Poison: A Case Report of Acquired Methemoglobinemia. 3217 28