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

End-tidal CO2 (PETCO2), arterial CO2 (PaCO2), mixed expired CO2 (PECO2), arterial and mixed venous oxygen contents were measured and the PaCO2 to PETCO2 difference (delta PCO2), physiologic dead space to tidal volume ratios (VD/VT) and venous admixture (Qs/Qt) were calculated in 41 anesthetized infants and children undergoing repair of congenital cardiac lesions. Eighteen children were acyanotic; 9 with normal pulmonary blood flow (PBF) and normal intracardiac anatomy (normal group); and 9 with increased PBF (acyanotic group). Twenty-three children were cyanotic; 14 with right to left intracardiac shunts and decreased PBF (cyanotic (D) group); and 9 with mixing lesions with normal or increased PBF (cyanotic (I) group). Correlations between PaCO2 and PETCO2 in the four groups of children were carried out and the relationship of delta PCO2 to VD/VT and Qs/Qt was determined. PETCO2 correlated closely with the PaCO2 in the normal and acyanotic groups (r2 = 0.97 and 0.91, respectively) and the lines of regression for the relationship between PaCO2 and PETCO2 for both groups did not differ from the line of identity (P less than or equal to 0.05). Mean +/- SD VD/VT for the normal and acyanotic groups were 0.35 +/- 0.17 and 0.39 +/- 0.19, respectively (NS). Corresponding values for the cyanotic (D) group and cyanotic (I) group were 0.38 +/- 0.16 and 0.55 +/- 0.16, respectively (NS), and were significantly greater than those from the normal and acyanotic groups (P less than 0.05). The relationship of delta PCO2 to VD/VT and Qs/Qt demonstrated that VD/VT was the most important determinant of delta PCO2, but in instances where Qs/Qt were large (e.g., cyanotic congenital heart disease) the percentage contribution of Qs/Qt to the delta PCO2 can be considerable.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Physiologic dead space, venous admixture, and the arterial to end-tidal carbon dioxide difference in infants and children undergoing cardiac surgery. 249 9

Oxygen consumption (VO2, ml min-1) and carbon dioxide elimination (VCO2, ml min-1), minute ventilation (VE), tidal volume (VT), rate of ventilation (f) and end-tidal carbon dioxide concentration (E'CO2%) were measured in 38 infants and children (body weights 3.6-25 kg). Four children (body weight less than 5 kg) had congenital heart malformations and were studied during controlled mechanical ventilation, whereas the remainder (n = 34) who were healthy, breathed spontaneously. Anaesthesia was maintained with oxygen in air (FIO2 0.45) and halothane through a non-rebreathing circuit. Minute ventilation was measured by pneumotachography, E'CO2 with an in-line infra-red carbon dioxide meter and gas concentrations with a mass spectrometer. There were no differences in VO2 and VCO2 between children with and without heart disease. VO2 was related to body weight by the equation: VO2 = 5.0 x kg + 19.8 (r = 0.94) and VCO2 to body weight by the equation: VCO2 = 4.8 x kg + 6.4 (r = 0.94). There were no differences between VO2 or VCO2 before and after the start of surgery. In 11 of 21 patients weighing less than 10 kg, a reduced VCO2 was noted, giving respiratory quotients of less than 0.7. It is speculated that this age-dependent variation of VCO2 may result from partial inhibition of lipolysis in brown adipose tissue produced by halothane.
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PMID:Oxygen consumption and carbon dioxide elimination in infants and children during anaesthesia and surgery. 249 15

From February 1985 through June 1987, 50 newborn infants in whom maximal ventilator therapy failed (80% predicted mortality) were treated with extracorporeal membrane oxygenation (ECMO) according to the following inclusion criteria: arterial oxygen tension less than 50 torr (alveolar-arterial oxygen gradient greater than 630 torr) for 2 hours or arterial oxygen tension less than 60 torr (alveolar-arterial oxygen gradient greater than 620 torr) for 8 hours. Criteria for exclusion from ECMO therapy included birth weight less than 2000 gm, gestational age less than 35 weeks, presence of intracranial hemorrhage, presence of other major congenital anomalies including cyanotic heart disease, and high levels of ventilatory support for more than 7 days. Mean birth weight was 3.28 +/- 0.56 kg, mean gestational age was 39.6 +/- 1.7 weeks, and mean age at the start of ECMO was 48.6 +/- 36.9 hours. Meconium aspiration, usually associated with persistent pulmonary hypertension, was the most common cause of pulmonary failure (62%). Mean pre-ECMO arterial oxygen tension during maximal ventilatory and pharmacologic support was 34.5 +/- 14.5 torr. Mean ventilatory support immediately before the institution of ECMO was as follows: peak inspiratory pressure 46.8 +/- 9.9 cm H2O, positive end-expiratory pressure 4.6 +/- 1.6 cm H2O, and intermittent mandatory ventilation rate 101.0 +/- 22.7 breaths/min with all patients receiving an inspired oxygen fraction of 1.0. Lung management to prevent pulmonary atelectasis during ECMO consisted of moderate levels of positive end-expiratory pressure (mean 10.3 +/- 2.6 cm H2O, range 8 to 14 in 94% of patients. Other mean ventilator parameters during ECMO were as follows: peak inspiratory pressure 22.8 +/- 1.6 cm H2O, intermittent mandatory ventilation rate 11.8 +/- 2.9, and inspired oxygen fraction 0.21. The overall long-term patient survival rate was 90%. Mean values for arterial blood gases and ventilator settings immediately after the discontinuation of ECMO were as follows: oxygen tension 78.4 +/- 22.1 torr, pH 7.39 +/- 0.10, carbon dioxide tension 37.4 +/- 10.7 torr, peak inspiratory pressure 25.2 +/- 3.9 cm H2O, positive end-expiratory pressure 5.6 +/- 1.2 cm H2O, and intermittent mandatory ventilation rate 41.3 +/- 12.6 with an inspired oxygen fraction of 0.42 +/- 0.17. Despite slightly higher levels of ventilator support (peak inspiratory pressure 46.8 versus 45.0 cm H2O, not significant) mean pre-ECMO oxygen tension was significantly lower than that reported from the National ECMO Registry (34.5 versus 42.0 torr, p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Extracorporeal membrane oxygenation for neonatal respiratory failure. A report of 50 cases. 270 62

Cardio-pulmonary exercise testing was performed in 99 normal subjects and 382 patients with cardiac disease in order to evaluate anaerobic threshold (AT) and related parameters as indices for assessing the severity of heart failure. AT could be determined easily during ergometer exercise testing with ramp protocol by monitoring minute ventilation (VE), oxygen uptake (VO2) and carbon dioxide output (VCO2). Peak VO2 and the ratio of VO2 rising to work rate increment (delta VO2/delta WR) were also determined. There was good correlation between the AT determined by respiratory measurement and that determined by arterial lactic acid concentration (r = 0.93, n = 15). The reproducibility of AT was excellent between 2 testings with a 3-hour interval. AT (ml/min/kg) and peak VO2 (ml/min/kg) declined with age, and males showed higher values than females in both indices. %AT, determined by the predicted AT values of each age and sex, decreased as NYHA class progressed as follows: 90.2 +/- 15.4% in class I, 76.9 +/- 13.8% in class II, and 59.7 +/- 11.9% in class III. Although delta VO2/delta WR was not influenced by age or sex, it also decreased as the severity of heart disease progressed. These results suggest that indices from cardiopulmonary exercise testing, especially AT, are closely related to the pathophysiology of heart failure, so that they are objective and reliable parameters for evaluation of the severity of heart failure and are sensitive enough to detect the efficacy of therapeutic intervention for heart failure.
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PMID:Severity and pathophysiology of heart failure on the basis of anaerobic threshold (AT) and related parameters. 271 76

In the 1967-1986 in the Czechoslovak State spa Sliac 961 (48.15%) men and 1035 (51.85%) women after surgical operations on the heart were followed up during the second rehabilitation stage. The operations were made because of the following indications: acquired rheumatic valvular defects 1208 (60.52%), congenital heart disease 461 (23.10%), ischaemic heart disease 260 (13.03%), myxomas and thrombi of the left atrium 31 (1.55%), pericardiectomy was performed in 36 (1.80%). As to surgical operations, commissurotomy and commissurolysis were performed in 724 (36.27%) an artificial prosthesis was implanted in 330 (16.53%), homotransplants in 151 (7.57%) autotransplants in 3 (0.15%), aortocoronary by-pass/revascularization in 260 (13.03), surgical operations on account of congenital heart disease, thrombi and myxomas of the left atrium were performed in 492 (24.65%) of the patients. Rehabilitation care comprised in addition to remedial exercise a therapeutic regime, clinical and laboratory examinations, dietotherapy, medicamentous and physical therapy and carbon dioxide baths. After rehabilitation care objective improvement was recorded in 850 (42.59%), subjective improvement in 953 (47.74%) no change in 143 (7.16%), deterioration in 47 (2.35%), and three patients (0.15%) died.
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PMID:[Evaluation of patients after heart surgery in the 20-year period of the 2d rehabilitation phase (1967-1986) in Sliac]. 280 Mar 58

The single breath test for carbon dioxide (SBT-CO2) is the plot of expired FCO2 or CO2% against expired volume. It can be monitored during anaesthesia and in the intensive care unit with modest additions to generally available equipment. This paper describes some aspects of a computer program for presenting SBT-CO2 during controlled ventilation, in particular, the corrections to the primary data necessary for scientific accuracy. Examples are given of how the use of SBT-CO2 has increased our understanding of factors which influence the arterial-end-tidal PCO2 difference (PaCO2-PE,CO2). PaCO2-PE, CO2 is, in a given individual, usually dependent on tidal volume and frequency. Changes in lung volume and manoeuvres such as opening the pleura also affect gas exchange. Monitoring CO2 elimination gives a measure of metabolic rate if ventilation and pulmonary perfusion are maintained. This facilitates ventilatory therapy in situations where CO2 production is greatly increased, e.g. sepsis and tetanus. On the other hand, if metabolism and ventilation are unchanged, a reduction in CO2 elimination implies reduced pulmonary perfusion. This can be seen during increased right-left shunting, such as in surgery in patients with congenital heart disease.
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PMID:On-line expiratory CO2 monitoring. 309 79

Minute ventilation (VE), tidal volume (VT), carbon dioxide elimination (VCO2), and end-tidal (PETCO2) and arterial CO2 tensions (PaCO2) were measured in 39 anesthetized infants and children with body weights ranging from 3.1 to 31 kg. Eighteen children had normal cardiopulmonary function, seven had acyanotic congenital heart disease, and 11 had cyanotic congenital heart disease. One child had left heart failure and pulmonary congestion, and two had severe parenchymal lung disease. To evaluate differences between pulmonary gas exchange calculated from PaCO2 versus PETCO2, dead space volume (VD) and alveolar ventilation (VA) based on a PaCO2 (VDa, VAa) as well as on PETCO2 (VDET, VAET) were performed, and correlations between PaCO2-PETCO2, VDa/VT-VDET/VT, and VAa-VAET were carried out. It was demonstrated that in normal children, as well as in those with acyanotic congenital heart disease, PETCO2 correlated closely with PaCO2 (r = 0.94, 0.98, respectively). In children with cyanotic congenital heart disease, however, correlation between PETCO2 and PaCO2 was relatively poor (r = 0.61). Mean values for PaCO2 were significantly higher than PETCO2 in the cyanotic children (P less than 0.01), resulting in significant underestimation of physiologic dead space (P less than 0.05) and significant overestimation of alveolar ventilation (P less than 0.01). In three patients with pulmonary disease, large differences between PaCO2 and PETCO2 were comparable with those observed in the children with cyanotic congenital heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relationship between invasive and noninvasive measurements of gas exchange in anesthetized infants and children. 310 50

Fourteen children with congenital heart disease and associated pulmonary hypertension (preoperative mean pulmonary artery pressure (MPAP) 48 mm Hg +/- 1 SEM were examined to determine the effect of arterial carbon dioxide tension (PaCO2) and pH on pulmonary and systemic hemodynamics after surgical repair. Baseline measurements were obtained with hyperventilation to PaCO2 20 to 30 mm Hg (pH 7.56 +/- 0.01 mm Hg). The addition of carbon dioxide to inspired gas to achieve a PaCO2 40 to 45 mm Hg (pH 7.35 +/- 0.01) resulted in a significant increase in MPAP, from 32 +/- 5 mm Hg to 47 +/- 8 mm Hg (p less than 0.05). An increase in mean cardiac index (CI) from 2.7 +/- 0.3 L/min/m2 to 3.3 +/- 0.3 L/min/m2 (p less than 0.05) explained in part the associated increase in MPAP. For a subgroup of eight patients with postoperative MPAP greater than 30 mm Hg (at pH 7.35 to 7.40), pulmonary vascular resistance index (PVRI) also significantly increased (p less than 0.05) as PaCO2 was increased, implying a direct pulmonary vasodilating effect of alkalosis. Removal of carbon dioxide from inspired gas returned hemodynamic values to baseline. The higher the MPAP at physiologic pH the greater the absolute amount of MPAP reduction and PVRI reduction (p less than 0.05) with alkalosis. No complications from alkalosis were seen. We suggest that a trial of hypocarbic alkalosis in the child with severe residual pulmonary hypertension after surgical repair of congenital heart disease is warranted to reduce right ventricular afterload.
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PMID:Effect of pH and PCO2 on pulmonary and systemic hemodynamics after surgery in children with congenital heart disease and pulmonary hypertension. 313 18

Carbon dioxide production and ventilatory efficiency were measured during undisturbed anaesthesia with intermittent positive pressure ventilation in 34 children about to undergo closed or open cardiac surgery. Anaesthesia was provided with fentanyl or halothane and nitrous oxide. There were 15 cyanotic and 19 acyanotic children. Children with cyanotic heart disease produced approximately 20% less carbon dioxide per unit body weight than acyanotic children, but ventilation was approximately 20% less efficient. Adequate ventilation should therefore be obtained when "normal" ventilation in relation to body weight is used in cyanotic children.
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PMID:Carbon dioxide production in cyanotic children during anaesthesia with controlled ventilation. 314 2

Noninvasive quantification of regional myocardial metabolism would be highly desirable to evaluate pathogenetic mechanisms of heart disease and their response to therapy. It was previously demonstrated that the metabolism of radiolabeled acetate, a readily utilized myocardial substrate predominantly metabolized to carbon dioxide (CO2) by way of the tricarboxylic acid cycle, provides a good index of oxidative metabolism in isolated perfused rabbit hearts because of tight coupling between the tricarboxylic acid cycle and oxidative phosphorylation. In the present study, in a prelude to human studies, the relation between myocardial clearance of carbon-11 (11C)-labeled acetate and myocardial oxygen consumption was characterized in eight intact dogs using positron emission tomography. Anesthetized dogs were studied during baseline conditions and again during either high or low work states induced pharmacologically. High myocardial extraction and rapid blood clearance of tracer yielded myocardial images of excellent quality. The turnover (clearance) of 11C radioactivity from the myocardium was biexponential with the mean half-time of the dominant rapid phase averaging 5.4 +/- 2.2, 2.8 +/- 1.3 and 11.1 +/- 1.3 min in control, high and low work load studies, respectively. No significant difference was found between the rate of clearance of 11C radioactivity from the myocardium measured noninvasively with positron emission tomography and the myocardial efflux of 11CO2 measured directly from the coronary sinus. The rate of clearance of the 11C radioactivity from the heart correlated closely with myocardial oxygen consumption (r = 0.90, p less than 0.001) as well as with the rate-pressure product (r = 0.95, p less than 0.001). Hence, the rate of oxidation of 11C-acetate can be determined noninvasively with positron emission tomography, providing a quantitative index of oxidative metabolism under diverse conditions.
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PMID:Noninvasive assessment of canine myocardial oxidative metabolism with carbon-11 acetate and positron emission tomography. 326 28


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