29 Dec 11

Pulse contour analysis and transesophageal echocardiography: a comparison of measurements of cardiac output during laparoscopic colon surgery

Posted in Anesthesia, Echocardiography, Laparoscopic surgery at 2:02 by Laci

By Mario R. Concha, V Mertz, L I Cortínez, K A González, J Butte

Anesth Analg 2009;109:114-118

Pulse wave analysis (PWA) allows cardiac output (CO) measurement after calibration by transpulmonary thermodilution. A PWA system that does not require previous calibration, the FloTrac/Vigileo (FTV), has been recently developed. We compared determinations of CO made with the FTV to simultaneous measurements using transesophageal echocardiography (TEE).

Methods
Ten ASA I-II patients scheduled for laparoscopic colorectal surgery were studied. A radial 20-gauge cannula was inserted and connected to a hemodynamic monitor and a FTV system for PWA and determination of CO (COPWA). TEE CO (COTEE) was determined as previously described. Measurements were made after intubation, 5 min after establishing the lithotomy position, 5 min after establishing pneumoperitoneum, every 30 min, or each time mean arterial blood pressure decreased below basal values. Statistical analysis was made with the Bland and Altman method.

Results
Eighty-eight measurements were compared. The COTEE values ranged from 3.23 to 12 Lt/min (mean 6.21 ± 1.85). Values for COPWA ranged from 2.9 to 8.5 Lt/min (mean 4.84 ± 1.14). Bias was 1.17 and limits of agreement −2.02 and 4.37. The percentage error between all COTEE and COPWA measurements was 40% (27%-50%) mean (range).

Conclusions
During laparoscopic colon surgery, clinically important differences were observed between CO determinations made with TEE and FTV.

19 Sep 10

Aortic stenosis severity: do we need a new concept?

Posted in Echocardiography, Valvular disease at 1:25 by Laci

By H Baumgartner, C Otto

JACC 2009;54:1012-1013

Aortic stenosis (AS) is the most frequent indication for valve replacement in Europe and North America, and correct diagnosis and timing of surgery are critical. Although it is evident that patients with symptoms attributable to severe AS require prompt valve replacement, there remain some unresolved issues in clinical decision making.

Usefulness of the valvuloarterial impedance to predict adverse outcome in asymptomatic aortic stenosis

Posted in Echocardiography, Valvular disease at 0:22 by Laci

By Z Hachicha, J Dumesnil, P Pibarot

JACC 2009;54:1003-1011

This study was designed to examine the prognostic value of valvuloarterial impedance (Zva) in patients with aortic stenosis (AS).

We previously showed that the Zva is superior to standard indexes of AS severity in estimating the global hemodynamic load faced by the left ventricle (LV) and predicting the occurrence of LV dysfunction. This index is calculated by dividing the estimated LV systolic pressure (systolic arterial pressure + mean transvalvular gradient) by the stroke volume indexed for the body surface area.

Methods
We retrospectively analyzed the clinical and echocardiographic data of 544 consecutive patients having at least moderate AS (aortic jet velocity =2.5 m∑s-1) and no symptoms at baseline. The primary end point for this study was the overall mortality regardless of the realization of aortic valve replacement (AVR).

Results
Four-year survival was significantly (p < 0.001) lower in the patients with a baseline Zva =4.5 mm Hg∑ml-1∑m2 (65 ± 5%) compared with those with Zva between 3.5 and 4.5 mm Hg∑ml-1∑m2 (78 ± 4%) and those with Zva =3.5 mm Hg∑ml-1∑m2 (88 ± 3%). The risk of mortality was increased by 2.76-fold in patients with Zva =4.5 mm Hg∑ml-1∑m2 and by 2.30-fold in those with a Zva between 3.5 and 4.5 mm Hg∑ml-1∑m2 after adjusting for other risk factors and type of treatment (surgical vs. medical).

Conclusions
Increased Zva is a marker of excessive LV hemodynamic load, and a value >3.5 successfully identifies patients with a poor outcome. These findings suggest that beyond standard indexes of stenosis severity, the consideration of Zva may be useful to improve risk stratification and clinical decision making in patients with AS.

25 May 09

Echocardiographic diagnosis of pulmonary artery occlusion pressure elevation during weaning from mechanical ventilation

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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