Combined effects of nitric oxide and oxygen during acute pulmonary vasodilator testing.
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OBJECTIVES: We compared the ability of inhaled nitric oxide (NO), oxygen (O2) and nitric oxide in oxygen (NO+O2) to identify reactive pulmonary vasculature in pulmonary hypertensive patients during acute vasodilator testing at cardiac catheterization. BACKGROUND: In patients with pulmonary hypertension, decisions regarding suitability for corrective surgery, transplantation and assessment of long-term prognosis are based on results obtained during acute pulmonary vasodilator testing. METHODS: In group 1, 46 patients had hemodynamic measurements in room air (RA), 100% O2, return to RA and NO (80 parts per million [ppm] in RA). In group 2, 25 additional patients were studied in RA, 100% O2 and 80 ppm NO in oxygen (NO+O2). RESULTS: In group 1, O2 decreased pulmonary vascular resistance (PVR) (mean+/-SEM) from 17.2+/-2.1 U.m2 to 11.1+/-1.5 U.m2 (p < 0.05). Nitric oxide caused a comparable decrease from 17.8+/-2.2 U.m2 to 11.7+/-1.7 U.m2 (p < 0.05). In group 2, PVR decreased from 20.1+/-2.6 U.m2 to 14.3+/-1.9 U.m2 in O2 (p < 0.05) and further to 10.5+/-1.7 U.m2 in NO+O2 (p < 0.05). A response of 20% or more reduction in PVR was seen in 22/25 patients with NO+O2 compared with 16/25 in O2 alone (p = 0.01). CONCLUSIONS: Inhaled NO and O2 produced a similar degree of selective pulmonary vasodilation. Our data suggest that combination testing with NO + O2 provides additional pulmonary vasodilation in patients with a reactive pulmonary vascular bed in a selective, safe and expeditious fashion during cardiac catheterization. The combination of NO+O2 identifies patients with significant pulmonary vasoreactivity who might not be recognized if O2 or NO were used separately. (+info)
Long-term morbidity and mortality following hypoxaemic lower respiratory tract infection in Gambian children.
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Acute lower respiratory infections (ALRI) are the main cause of death in young children worldwide. We report here the results of a study to determine the long-term survival of children admitted to hospital with severe pneumonia. The study was conducted on 190 Gambian children admitted to hospital in 1992-94 for ALRI who survived to discharge. Of these, 83 children were hypoxaemic and were treated with oxygen, and 107 were not. On follow-up in 1996-97, 62% were traced. Of the children with hypoxaemia, 8 had died, compared with 4 of those without. The mortality rates were 4.8 and, 2.2 deaths per 100 child-years of follow-up for hypoxaemic and non-hypoxaemic children, respectively (P = 0.2). Mortality was higher for children who had been malnourished (Z-score < -2) when seen in hospital (rate ratio = 3.2; 95% confidence interval (CI) = 1.03-10.29; P = 0.045). Children with younger siblings experienced less frequent subsequent respiratory infections (rate ratio for further hospitalization with respiratory illness = 0.15; 95% CI = 0.04-0.50; P = 0.002). Children in Gambia who survive hospital admission with hypoxaemic pneumonia have a good prognosis. Survival depends more on nutritional status than on having been hypoxaemic. Investment in oxygen therapy appears justified, and efforts should be made to improve nutrition in malnourished children with pneumonia. (+info)
Electrocardiographic signs of chronic cor pulmonale: A negative prognostic finding in chronic obstructive pulmonary disease.
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BACKGROUND: Chronic cor pulmonale (CCP) is a strong predictor of death in chronic obstructive pulmonary disease (COPD). The aims of this study were to assess the prognostic role of individual ECG signs of CCP and of the interaction between these signs and abnormal arterial blood gases. METHODS AND RESULTS: Two hundred sixty-three patients (217 men) with COPD, mean age 67+/-9 years, were grouped according to whether they had no ECG signs (group 1, n=100) or >/=1 ECG signs (group 2, n=163) of CCP and were followed up for 13 years after an exacerbation of respiratory failure. The median survival was significantly shorter in group 2 than in group 1 (2.58 versus 3. 45 years, respectively; Mantel-Cox test, 9.58; P=0.002). The Cox regression analysis identified S1S2S3 pattern, right atrial overload (RAO), and alveolar-arterial oxygen gradient (PAO2-PaO2) >48 mm Hg during oxygen therapy as the strongest predictors of death, with hazard rate (HR)=1.81 (95% CI, 1.22 to 2.69), HR=1.58 (95% CI, 1.15 to 2.18), and HR=1.96 (95% CI, 1.19 to 3.25), respectively. The median survivals of patients having both S1S2S3 pattern and RAO (n=14) and of patients having either S1S2S3 pattern or RAO (n=77) were 1.33 and 2.70 years, respectively (P=0.022). Group 2 patients had a 3-year survival of 18% or 53%, depending on whether their PAO2-PaO2 during oxygen therapy was or was not >48 mm Hg. CONCLUSIONS: Some ECG signs of CCP and PAO2-PaO2 >48 mm Hg during oxygen therapy qualified as a simple and inexpensive tool for targeting subsets of COPD patients with severe or very severe short-term prognosis. (+info)
Early inhaled glucocorticoid therapy to prevent bronchopulmonary dysplasia.
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BACKGROUND: The safety and efficacy of inhaled glucocorticoid therapy for asthma stimulated its use in infants to prevent bronchopulmonary dysplasia. We tested the hypothesis that early therapy with inhaled glucocorticoids would decrease the frequency of bronchopulmonary dysplasia in premature infants. METHODS: We conducted a randomized, multicenter trial of inhaled beclomethasone or placebo in 253 infants, 3 to 14 days old, born before 33 weeks of gestation and weighing 1250 g or less at birth, who required ventilation therapy. Beclomethasone was delivered in a decreasing dosage, from 40 to 5 microg per kilogram of body weight per day, for four weeks. The primary outcome measure was bronchopulmonary dysplasia at 28 days of age. Secondary outcomes included bronchopulmonary dysplasia at 36 weeks of postmenstrual age, the need for systemic glucocorticoid therapy, the need for bronchodilator therapy, the duration of respiratory support, and death. RESULTS: One hundred twenty-three infants received beclomethasone, and 130 received placebo. The frequency of bronchopulmonary dysplasia was similar in the two groups: 43 percent in the beclomethasone group and 45 percent in the placebo group at 28 days of age, and 18 percent in the beclomethasone group and 20 percent in the placebo group at 36 weeks of postmenstrual age. At 28 days of age, fewer infants in the beclomethasone group than in the placebo group were receiving systemic glucocorticoid therapy (relative risk, 0.6; 95 percent confidence interval, 0.4 to 1.0) and mechanical ventilation (relative risk, 0.8; 95 percent confidence interval, 0.6 to 1.0). CONCLUSIONS: Early beclomethasone therapy did not prevent bronchopulmonary dysplasia but was associated with lower rates of use of systemic glucocorticoid therapy and mechanical ventilation. (+info)
Evaluation of routine tracheal extubation in children: inflating or suctioning technique?
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We studied prospectively the effects of the technique of tracheal extubation on arterial haemoglobin oxygen saturation (SpO2) in 120 ASA I-III children, mean age 5.3 (range 0.25-16.9) yr. At completion of surgery, tracheal extubation was performed when spontaneous ventilation had resumed, children were fully awake and SpO2 was 99-100%. Children were allocated randomly to receive a single lung inflation manoeuvre with 100% oxygen before tracheal extubation (group I; n = 59) or to have the tracheal tube removed while applying suction through the tube (group S; n = 61). SpO2 was monitored during the first 5 min after tracheal extubation in the operating room. Supplementary oxygen was given if SpO2 decreased to less than 92%. The time between tracheal extubation and decrease in SpO2 to 92% (T92) was recorded. Children in group S required oxygen administration more frequently after tracheal extubation than those in group I (65.6% vs 45.8%; P = 0.04), and had a three-fold shortening of T92 (mean 25 (SD 19) s vs 85 (63) s; P = 0.0001). These effects were more pronounced in children less than 4 yr of age compared with older children. We conclude that tracheal extubation greatly impaired oxygenation and therefore administration of oxygen was appropriate. This impairment was more marked when suction was used, and in young children. Lung inflation with 100% oxygen before removal of the tracheal tube is advised before routine tracheal extubation in children. (+info)
Vital capacity and tidal volume preoxygenation with a mouthpiece.
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We have measured oxygen wash-in in 20 volunteers undergoing preoxygenation with a face mask, mouthpiece alone and a mouthpiece with a noseclip, in a crossover study. Tidal volume breathing and maximal deep breath techniques were studied with each type of equipment. When tidal volume breathing was used, the face mask and mouthpiece with noseclip were comparable, but the mouthpiece alone achieved a lower end-expiratory oxygen concentration than the two other methods after 3 min (P < 0.001 and P < 0.01), and after 5 min (P < 0.05 in each case). Conversely, during preoxygenation with vital capacity breaths, the mouthpiece and mouthpiece with noseclip were comparable, and both were more effective than the face mask (P < 0.001). In a second study, 20 patients who had undergone preoxygenation before induction of anaesthesia were asked later if they would have preferred the face mask or mouthpiece for this procedure. Significantly more patients (14 of 18 who expressed a preference) favoured the mouthpiece (P < 0.05; confidence limits 0.56-0.92). (+info)
Inadvertent inhalation anaesthesia during surgery under retrobulbar eye block.
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I describe a case of inadvertent inhalation anaesthesia during surgery under retrobulbar anaesthesia and its management. Some of the hazards of supplementary oxygen delivery during monitored anaesthetic care and the actions taken to prevent this mishap recurring are discussed. (+info)
Cost minimisation analysis of provision of oxygen at home: are the drug tariff guidelines cost effective?
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OBJECTIVES: To determine the level of oxygen cylinder use at which it becomes more cost effective to provide oxygen by concentrator at home in Northern Ireland, and to examine potential cost savings if cylinder use above this level had been replaced by concentrator in 1996. DESIGN: Cost minimisation analysis. SETTING: Area health boards in Northern Ireland. MAIN OUTCOME MEASURES: Cost effective cut off point for switch to provision of oxygen from cylinder to concentrator. Potential maximum and minimum savings in Northern Ireland (sensitivity analysis) owing to switch to more cost effective strategy on the basis of provision of cylinders in 1996. RESULTS: In Northern Ireland it is currently cost effective to provide oxygen by concentrator when the patient is using three or more cylinders per month independent of the duration of the prescription. More widespread use of concentrators at this level of provision is likely to lead to a cost saving. CONCLUSIONS: The Drug Tariff prescribing guidelines, advocating that provision of oxygen by concentrator becomes cheaper when 21 cylinders are being used per month-are currently inaccurate in Northern Ireland. Regional health authorities should review their current arrangements for provision of oxygen at home and perform a cost analysis to determine at what level it becomes more cost effective to provide oxygen by concentrator. (+info)