PubMed · 12043549
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Cameron Bardsley. 2002. Methaemoglobinaemia.. https://pubmed.ncbi.nlm.nih.gov/12043549/
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AIMS: In chronic heart failure (CHF) patients, the ventilation (Ve) needed to eliminate metabolically produced CO(2) during exercise (i.e. the Ve/Vco(2) slope) is a strong prognosticator. Ve/Vco(2) slope determinants are the dead space-tidal volume (Vd/Vt) ratio and the arterial CO(2) partial pressure (Paco(2)). We aimed at defining the respective prognostic role of these two variables. METHODS AND RESULTS: One hundred and twenty-eight stable CHF patients (average left ventricular ejection fraction 34+/-10%) underwent cardiopulmonary exercise testing and blood gas analysis. The prognostic relevance of the Ve/Vco(2) slope, Vd/Vt, and Paco(2) at peak exercise was evaluated by the Kaplan-Meier approach with log-rank testing and by multivariate Cox regression analysis. During a mean period of 31.3+/-20 months, 24 patients died from cardiac causes. In univariate analysis, predictors of death included the use of anti-aldosterone drugs, low peak Vo(2), peak Ve/Vo(2), peak Paco(2) and high Ve/Vco(2) slope, and peak Vd/Vt. Multivariate analysis identified a low peak Paco(2) (<35 mmHg) as the strongest independent prognostic indicator [hazard ratio 4.65, 95% confidence interval (CI) (1.695-12.751), P=0.003] that primarily accounts for the Ve/Vco(2) slope prognostic power. CONCLUSION: These findings imply that regulatory mechanisms involved in the tight control of ventilatory command and blood gas tension, rather than lung function abnormalities, play a critical pathophysiological role in the exercise ventilation inefficiency of CHF patients.
BACKGROUND: Patients with chronic obstructive pulmonary disease have an increased risk of mortality and morbidity after open-heart surgery. This is mostly due to a dysfunction of the pulmonary system during and after non-pulsatile cardiopulmonary bypass. The purpose of this study was to compare the pulsatile and non-pulsatile blood flows during cardiopulmonary bypass in patients with chronic obstructive pulmonary disease. MATERIAL/METHODS: This is a prospective study. Ten patients with chronic obstructive pulmonary disease had open-heart surgery with pulsatile flow, and another 9 patients with non-pulsatile flow. We compared clinical, hemodynamic, biochemical and hematological parameters and arterial and venous blood gases before initiating cardiopulmonary bypass, at aortic cross-clamping and de-clamping, and 1 and 24 hours postoperative. RESULTS: In the pulsatile flow group, systemic vascular resistance at the time of aortic cross clamping (p=0.041), pulmonary vascular resistance 1 hour postoperative (p=0.05), and the percentage of neutrophils 1 hour postoperative (p=0.034) were significantly lower than those of the non-pulsatile group. Though white blood cell count was significantly high in the pulsatile group 1 hour postoperative, absolute neutrophil count was significantly low (p=0.034). The postoperative mechanical ventilation period was significantly shorter in the pulsatile flow group (p=0.016). CONCLUSIONS: Pulsatile blood flow during cardiopulmonary bypass has a favorable influence on patients with chronic obstructive pulmonary disease, who have high risk in open-heart surgery.
The Food and Drug Administration (FDA) is requiring the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for the following three class III preamendments devices: Indwelling blood oxyhemoglobin concentration analyzer, cardiopulmonary bypass pulsatile flow generator, and the ocular plethysmograph. The agency also is summarizing its proposed findings regarding the degree of risk of illness or injury designed to be eliminated or reduced by requiring the devices to meet the statute's approval requirements and the benefits to the public from the use of the devices. This action implements certain statutory requirements.