25 May 09
Posted in Echocardiography, Mechanical ventilation at 2:15 by Laci
By B Lamia, J Maizel, A Ochagavia, D Chemla, D Osman, C Richard, JL Teboul
Crit Care Med 2009; 37:1696-1701
Weaning-induced pulmonary edema is a cause of weaning failure in high-risk patients. The diagnosis may require pulmonary artery catheterization to demonstrate increased pulmonary artery occlusion pressure (PAOP) during weaning. Transthoracic echocardiography can estimate left ventricular filling pressures using early (E) and late (A) peak diastolic velocities measured with Doppler transmitral flow, and tissue Doppler imaging of mitral annulus velocities including early (Ea) peak diastolic velocity. We tested the hypothesis that E/A and E/Ea could be used to detect weaning-induced PAOP elevation defined by a PAOP >=18 mm Hg during a spontaneous breathing trial (SBT).
Measurements and main results
We included 39 patients who previously failed two consecutive SBTs. A third SBT was performed over a maximum 1-hour period using a T-piece. The PAOP, E/A, and E/Ea were measured before and during this SBT. Receiver operating characteristic curves were constructed to determine the optimal sensitivity and specificity values of E/A and E/Ea obtained at the end of the SBT for predicting a weaning-induced PAOP elevation. Weaning-induced PAOP elevation occurred in 17 patients. A value of E/A >0.95 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 88% and a specificity of 68%. A value of E/Ea >8.5 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 94% and a specificity of 73%. The combination of E/A >0.95 and E/Ea >8.5 predicted a weaning-induced PAOP elevation with a sensitivity of 82% and a specificity of 91%.
Conclusion
At the end of an SBT, the combination of E/A >0.95 and E/Ea >8.5 measured with transthoracic echocardiography allowed an accurate noninvasive detection of weaning-induced PAOP elevation.
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16 Feb 09
Posted in Echocardiography, Heart failure/Cardiogenic shock at 0:43 by Laci
By J Grewal, R B McCully, G C Kane, C Lam, P A Pellikka
JAMA. 2009;301:286-294
Limited information exists regarding the role of left ventricular function in predicting exercise capacity and impact on age- and sex-related differences.
Objectives
To determine the impact of measures of cardiac function assessed by echocardiography on exercise capacity and to determine if these associations are modified by sex or advancing age.
Design
Cross-sectional study of patients undergoing exercise echocardiography with routine measurements of left ventricular systolic and diastolic function by 2-dimensional and Doppler techniques. Analyses were conducted to determine the strongest correlates of exercise capacity and the age and sex interactions of these variables with exercise capacity.
Setting
Large tertiary referral center in Rochester, Minnesota, in 2006.
Participants
Patients undergoing exercise echocardiography using the Bruce protocol (N = 2867). Patients with echocardiographic evidence of exercise-induced ischemia, ejection fractions lower than 50%, or significant valvular heart disease were excluded.
Main outcome measure
Exercise capacity in metabolic equivalents (METs).
Results
Diastolic dysfunction was strongly and inversely associated with exercise capacity. Compared with normal function, after multivariate adjustment, those with moderate/severe resting diastolic dysfunction (–1.30 METs; 95% confidence interval [CI], –1.52 to –0.99; P < .001) and mild resting diastolic dysfunction (–0.70 METs; 95% CI, –0.88 to –0.46; P < .001) had substantially lower exercise capacity. Variation of left ventricular systolic function within the normal range was not associated with exercise capacity. Left ventricular filling pressures measured by resting E/e’ of 15 or greater (–0.41 METs; 95% CI, –0.70 to –0.11; P = .007) or postexercise E/e’ of 15 or greater (–0.41 METs; 95% CI, –0.71 to –0.11; P = .007) were similarly associated with a reduction in exercise capacity, each in separate multivariate analyses. Individuals with impaired relaxation (mild dysfunction) or resting E/e’ of 15 or greater had a progressive increase in the magnitude of reduction in exercise capacity with advancing age (P < .001 and P = .02, respectively). Other independent correlates of exercise capacity were age (unstandardized β coefficient, –0.85 METs; 95% CI, –0.92 to –0.77, per 10-year increment; P < .001), female sex (–1.98 METs; 95% CI, –2.15 to –1.84; P < .001), and body mass index greater than 30 (–1.24 METs; 95% CI, –1.41 to –1.10; P < .001).
Conclusion
In this large cross-sectional study of those referred for exercise echocardiography and not limited by ischemia, abnormalities of left ventricular diastolic function were independently associated with exercise capacity.
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25 Jul 08
Posted in Echocardiography, Heart failure/Cardiogenic shock, Sepsis at 16:47 by Laci
By A Vieillard-Baron, V Caille, C Charron, G Belliard, B Page, F Jardin
Crit Care Med 2008;36:1701-1706
To evaluate the actual incidence of global left ventricular hypokinesia in septic shock.
Method
All mechanically ventilated patients treated for an episode of septic shock in our unit were studied by transesophageal echocardiography, at least once a day, during the first 3 days of hemodynamic support. In patients who recovered, echocardiography was repeated after weaning from vasoactive agents. Main measurements were obtained from the software of the apparatus. Global left ventricular hypokinesia was defined as a left ventricular ejection fraction of <45%.
Measurements and Main Results
During a 3-yr period (January 2004 through December 2006), 67 patients free from previous cardiac disease, and who survived for >48 hrs, were repeatedly studied. Global left ventricular hypokinesia was observed in 26 of these 67 patients at admission (primary hypokinesia) and in 14 after 24 or 48 hrs of hemodynamic support by norepinephrine (secondary hypokinesia), leading to an overall hypokinesia rate of 60%. Left ventricular hypokinesia was partially corrected by dobutamine, added to a reduced dosage of norepinephrine, or by epinephrine. This reversible acute left ventricular dysfunction was not associated with a worse prognosis.
Conclusion
Global left ventricular hypokinesia is very frequent in adult septic shock and could be unmasked, in some patients, by norepinephrine treatment. Left ventricular hypokinesia is usually corrected by addition of an inotropic agent to the hemodynamic support.
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14 Apr 08
Posted in Anesthesia, BNP, Echocardiography, Heart failure/Cardiogenic shock at 13:28 by Laci
By P B Messer, R Singh, F T McAuley, G Handley, B Peaston and C P Snowden
Anaesthesia 2008;63:482-487
Heart failure is a major risk factor for adverse postoperative events following non-cardiac surgery. The use of transthoracic echocardiogram as a pre-operative investigation to assess cardiac dysfunction has limitations in this setting. The N-Terminal fragment of B-Type natriuretic peptide (NT proBNP) has been used in screening for heart failure. We have investigated the use of NT proBNP as a screening tool for left ventricular systolic dysfunction to reduce the requirement for pre-operative echocardiograms. Ninety-eight pre-operative non-cardiac surgical patients scheduled to undergo echocardiography were assessed clinically and with an NT proBNP measurement. Echocardiogram was used to define two groups of patients depending on the presence or absence of abnormal left ventricular function and the NT proBNP level was compared between the groups using non-parametric and receiver-operator-characteristic (ROC) curve analysis. In terms of pre-operative screening, a NT proBNP of <38.2 pmol.l−1 had a 100% negative predictive value in predicting patients with normal left ventricular systolic function and would have prevented the requirement for echocardiogram in 43% of pre-operative patients. NT proBNP was superior to electrocardiological and clinical criteria for detection of a normal echocardiogram. This may have significant impact in the pre-operative assessment of patients undergoing non-cardiac surgery.
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