Abstract Background End-tidal carbon dioxide pressure ( et CO2 ) is widely used in anaesthesia and critical care in intubated patients. The aim of our preliminary study was to evaluate the ...feasibility of a simple device to predict capnia in spontaneously breathing patients in an emergency department (ED). Patients and methods This study was a prospective, nonblind study performed in our teaching hospital ED. We included nonintubated patients with dyspnea (≥18 years) requiring measurement of arterial blood gases, as ordered by the emergency physician in charge. There were no exclusion criteria. End-tidal CO2 was measured by an easy-to-use device connected to a microstream capnometer, which gave a continuous measurement and graphical display of the et CO2 level of a patient's exhaled breath. Results A total of 43 patients (48 measurements) were included, and the majority had pneumonia (n = 12), acute cardiac failure (n = 8), asthma (n = 7), or chronic obstructive pulmonary disease exacerbation (n = 6). Using simple linear regression, the correlation between et CO2 and Pa co2 was good ( R = 0.82). However, 18 measurements (38%) had a difference between et CO2 and Pa co2 of 10 mm Hg or more. The mean difference between the Pa co2 and et CO2 levels was 8 mm Hg. Using the Bland and Altman matrix, the limits of agreement were −10 to +26 mm Hg. Conclusion In our preliminary study, et CO2 using a microstream method does not seem to accurately predict Pa co2 in patients presenting to an ED for acute dyspnea.
Abstract Introduction Previous studies suggested that variation of pulse oximetric plethysmographic (POP) waveform amplitude (ΔPOP) could predict fluid responsiveness in mechanically ventilated ...patients. Our objective was to correlate the variations of ΔPOP and the variations of cardiac index (CI) induced by passive leg raising (PLR) in spontaneously breathing volunteers. Methods We studied 26 spontaneously breathing volunteers using a pulse oximeter attached to the middle finger. We assessed hemodynamic variables, including ΔPOP (%) (POPmax − POPmin )/(POPmax + POPmin )/2 and CI determined by transthoracic echocardiography at baseline (eg, semirecumbent position), during PLR at 60°, and back to baseline. Results Cardiac index significantly increased from 2.2 to 2.5 L/min·m2 ( P < .01) at 60° PLR. Conversely, ΔPOP significantly decreased from 22% to 15% ( P < .01) at 60° PLR. There was a weak correlation between CI and ΔPOP variations at 60° PLR ( r = 0.40; P < .01). The area under curve of the receiver operating characteristic curve for ΔPOP as a predictor of an increase of CI of 15% was not significant (0.67 ± 0.10; P = .16). Conclusion The variation of ΔPOP induced by PLR is not an accurate predictor of increase in CI.
To assess the performance of the Pulmonary Embolism Rule-out Criteria (PERC) and the age-modified PERC-35 tool in hospital emergency departments (EDs) for evaluating patients aged 35 years or ...younger. A secondary aim was to assess other decision-making criteria.
Post-hoc analysis of 3 European cohort studies. We included data for patients aged 35 years or younger suspected of PE who were followed for 3 months. The safety and efficacy of applying the PERC and PERC-35 were assessed with the diagnostic error rate (failure to detect PE) and the proportion of patients in whom a diagnosis of PE was ruled out. We also assessed the safety and efficacy of applying the YEARS and PEGeD criteria.
Data for 1235 patients aged 35 years or younger were analyzed. Twenty-two (1.8%; 95% CI, 1.2%-2.7%) PE cases were diagnosed at 3 months. Six (1.0%; 95% CI, 0.5%-2.2%) and 5 (0.9%; 95% CI, 0.4%-2.1%) PE cases were not diagnosed by the PERC and PERC-35 tools, respectively. These tools allowed PE to be ruled out in 591 (48.2%; 95% CI, 45.4%-51.0%) and 554 (46.2%; 95% CI, 43.4%-49.0%) cases, respectively. The error rates of the YEARS and PEGeD criteria, respectively, were 0.4% (95% CI, 0.1%-1.1%) and 0.5% (95% CI, 0.2%-1.2%); their efficacy was similar.
The safety and efficacy profiles of the PERC and PERC-35 algorithms were similar in patients aged 35 years or younger. However, the large confidence intervals we report do not allow us to confirm the safety of using the tools in patients in this age group.
Protein turnover in cardiac and skeletal muscle is affected by the provision of amino acids, particularly the branched chain amino acids (BCAA). The effect of each of the BCAA, valine, leucine, and ...isoleucine, on the systolic function of isolated normal or septic rat heart perfused as a Langendorff preparation was examined. Thirty normal control and 28 septic rats (cecal ligation and puncture) were perfused with either Krebs + 8.5 mM glucose or Krebs + 5.0 mM glucose and 3.5 mM valine, leucine, or isoleucine. Septic hearts perfused with Krebs + 8.5 mM glucose exhibited developed force (DF) and force velocity (dF/dt) levels which were reduced to an average of 45 and 50%, respectively, compared to normal controls, and improved by 35% during 60 min perfusion over measurements made at time zero. In normal hearts DF and dF/dt decreased significantly during perfusion with leucine (27%) and isoleucine (20%). In sepsis, perfusion with leucine and isoleucine resulted in a mild improvement in systolic function. However, valine was far less effective than leucine and isoleucine in maintaining systolic function in sepsis, due apparently to valine being a less efficient energy substrate for the cardiac muscle in a state of severe energy deficit. Thus, valine, leucine, and isoleucine seem to exert different effects on the systolic function of normal and septic isolated rat hearts.
Systolic properties and coronary flow were studied in Langendorff preparations of normal and septic rat hearts paced at 100, 200, 300, and 400 beats per minute. In addition, the effects of amino acid ...formulations differing in their branched chain amino acid (BCAA) concentration in normal and septic rat hearts were investigated. Our experiments demonstrated the following: in the normal isolated rat heart, Krebs plus glucose and Krebs plus glucose plus 42% BCAA are most effective in maintaining systolic properties, while Krebs plus glucose plus 15% or 100% BCAA were considerably less effective. Sepsis results in a significant decrease in the systolic properties of the isolated rat heart, and in a loss of the negative linear correlation between contractility and heart rate, probably the result of a diminishing intracellular load of contractile calcium. In the isolated septic rat heart, mechanical washout during perfusion has a beneficial effect, suggesting the presence of a myocardial depressant substance in sepsis. The use of a balanced amino acid mixture containing 42% BCAA exerts the greatest benefit in maintaining systolic properties and in improving coronary flow in the isolated septic rat heart.
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