Critical care medicine
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Critical care medicine · Apr 1990
Comparative StudyRelationship of bioimpedance to thermodilution and echocardiographic measurements of cardiac function.
Bioimpedance cardiography has been suggested as a noninvasive means to monitor cardiac function. However, this method has not been compared to more conventional techniques such as echocardiography. This study compared simultaneously obtained thermodilution cardiac output and right ventricular ejection fraction (RVEF), and echocardiographic left ventricular fractional shortening (LVFS), to bioimpedance cardiac output and the maximum first derivative of the bioimpedance signal (dZ/dtmax) during positive inotropic stimulation and preload reduction. ⋯ In summary, bioimpedance was significantly correlated with thermodilution cardiac output over a wide hemodynamic range. The peak first derivative of the bioimpedance signal dZ/dtmax may provide a noninvasive index of ventricular pump performance. Further studies are required to evaluate the diagnostic value of bioimpedance cardiography in the clinical setting.
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Critical care medicine · Apr 1990
Use of capnography in diagnosis of pulmonary embolism during acute respiratory failure of chronic obstructive pulmonary disease.
In chronic obstructive pulmonary disease (COPD) patients, there is a difference between PaCO2 and end-tidal partial pressure of CO2 (PetCO2). This gradient P(a-et)CO2 is due to ventilation/perfusion mismatching and deadspace, and is usually abolished by forced and prolonged expiration. We hypothesized that this gradient might not be canceled by forced expiration in the case of acute respiratory failure (ARF) related to pulmonary embolism (PE). ⋯ The two groups were comparable regarding mean age, severity of underlying chronic respiratory disease, PaCO2, PaO2, and hemodynamic data on admission. P(a-em)CO2 and R were significantly different in PE+ and PE- patients at 12 +/- 6.9 torr compared to 1 +/- 2.4 torr and at 28 +/- 14.8% compared to 2 +/- 6.2% (p less than .001), respectively. The positive predictive value of the test was 74%, but the negative predictive value 100% and the specificity was 65%, but sensitivity was 100%.(ABSTRACT TRUNCATED AT 250 WORDS)
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Critical care medicine · Apr 1990
Editorial CommentColloid versus crystalloid war--a time for truce.
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Critical care medicine · Apr 1990
Prediction of outcome of cardiopulmonary resuscitation from end-tidal carbon dioxide concentration.
Capnography is a valuable tool in the management of cardiac arrest, since end-tidal CO2 (PetCO2) correlates well with cardiac output and there are no other suitable noninvasive ways to measure this important variable during resuscitation. Animal studies also suggest that PetCO2 correlates well with the likelihood of resuscitation, but this has never been confirmed in humans. We prospectively studied 55 adult, nontraumatic prehospital cardiac arrest patients. ⋯ This difference was significant both in nonperfusing rhythms (asystole and ventricular fibrillation) and in potentially perfusing rhythms (electromechanical dissociation). An initial PetCO2 of 15 torr correctly predicted eventual return of pulse with a sensitivity of 71%, a specificity of 98%, a positive predictive value of 91%, and a negative predictive value of 91%. A receiver operating curve was generated for sensitivity and specificity of the test at varying PetCO2 thresholds.
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Critical care medicine · Apr 1990
Thermodilution cardiac output values obtained by using a centrally placed introducer sheath and right atrial port of a pulmonary artery catheter.
Thermodilution cardiac output measurements obtained using a centrally placed introducer sheath were compared with thermodilution cardiac outputs obtained using the right atrial port of a balloon-tip, flow-directed pulmonary artery catheter in 15 patients with cardiac failure. Cardiac output values were obtained by manually injecting 10 ml of iced, D5W alternately through the introducer sheath and the right atrial port of the flow-directed catheter. ⋯ The correlation between CORA and COSP was significant (r = .94, p less than .0001) and could be described by the formula CORA = 0.33 + 0.96 COSP. We conclude that when the right atrial port of a flow-directed catheter is nonfunctional, a thermodilution cardiac output obtained using a centrally placed introducer sheath offers a reliable alternative.