Anesth Analg 2005;100:901
© 2005 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000154228.09074.43
LETTER TO THE EDITOR
Impact of Volume Loading on Systolic Mitral Annular Velocity (Sm) by Tissue Doppler Imaging
Karim Bendjelid, MD
Surgical Intensive Care Division; University Hospital of Geneva; Geneva, Switzerland; karim.bendjelid{at}hcuge.ch
To the Editor:
We have read with great interest the study published by Amà et al. (1). They found that Sm was dependent from increase in preload and independent from change in afterload.
They speculated that no observed decrease in Sm value related to an increase in afterload observed in this study was due to a counterbalanced simultaneous phenomenon consisting of an increase in Sm due to expansion of end diastolic volume (EDV) (Table 1) with phenylephrine.
Although this explanation is physiologically acceptable for the phenylephrine group, we have a major concern about accepting the same hypothesis regarding no Sm change following nitroglycerine bolus (300–500 µg IV). Indeed, as shown in Table 2, EDV, stroke volume, and mean arterial pressure have decreased. This scenario assumes that systemic vascular resistance has not significantly changed (even in absence of measured central venous pressure and indexed hemodynamic values). In this setting, the physiological concept proposed by the authors to explain the above data is not valid, as no decrease in afterload has occurred. This study reminds us that the peripheral dilation of systemic arteries following IV nitroglycerine is dose dependent (2).
References
- Amà R, Segers P, Roosens C, et al. The effects of load on systolic mitral annular velocity by tissue Doppler imaging. Anesth Analg 2004;99:332–8.[Abstract/Free Full Text]
- Torfgard KE, Ahlner J. Mechanisms of action of nitrates. Cardiovasc Drugs Ther 1994;8:701–17.[Medline]
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