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Transthoracic Echocardiography Is Not Proven To Be the Principal Echocardiographic Test in the ICU

2005; Elsevier BV; Volume: 128; Issue: 3 Linguagem: Inglês

10.1378/chest.128.3.1887

1931-3543

William C. Culp,

Cardiovascular Function and Risk Factors

Dr. Joseph and his group 1 Joseph MX Disney PJ De Costa R et al. Transthoracic echocardiography to identify or exclude cardiac cause of shock. Chest. 2004; 126: 1592-1597 Abstract Full Text Full Text PDF PubMed Scopus (175) Google Scholar recently reported data in CHEST (November 2004) on the role of transthoracic echocardiography (TTE) in identifying cardiac etiologies of shock in the ICU. I congratulate the authors on their high rate of “adequate” TTE images (99%), but I find that it is a rate far exceeding the more common 80% “adequate” rate that is seen in many clinical practices, even with tissue harmonic imaging. Of note, the authors do not strictly define their criteria for image “adequacy,” which is the crux of the study. Further, there is no mention of the role of echogenic contrast agents, which have been shown to consistently improve image quality in difficult-to-image patients. 2 Yu EH Sloggett CE Iwanochko RM et al. Feasibility and accuracy of left ventricular volumes and ejection fraction determination by fundamental, tissue harmonic, and intravenous contrast imaging in difficult-to-image patients. J Am Soc Echocardiogr. 2000; 13: 216-224 Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar Cardiac index, certainly a key value in patients who are in shock, was only able to be measured by TTE in 46% of the patients, whereas transesophageal echocardiography (TEE) studies can routinely derive this value in at least 90% of patients. 3 Feinberg MS Hopkins WE Davila-Roman VG et al. Multiplane transesophageal echocardiographic Doppler imaging accurately determines cardiac output measurements in critically ill patients. Chest. 1995; 107: 769-773 Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar , 4 Poelaert J Schmidt C Van Aken H et al. A comparison of transoesophageal echocardiographic Doppler across the aortic valve and the thermodilution technique for estimating cardiac output. Anaesthesia. 1999; 54: 128-136 Crossref PubMed Scopus (63) Google Scholar Post-cardiac surgery patients were excluded from this study, as the authors note, but this is a very important group of patients who are at high risk for cardiogenic shock in whom TEE has been well-validated. Further, this study does not directly compare TTE to TEE. All of these points make me a bit hesitant to agree with the authors’ concluding statement, “TTE should be considered not only the initial, but also the principal echocardiographic test in the critical care environment.” As TTE technologies improve, this indeed may become the case, but the data presented here do not yet support such a change in clinical practice. Carbon Dioxide KineticsCHESTVol. 128Issue 3PreviewIn his editorial on the pitfalls of the routine use of pulse oximetry in the ICU in a recent issue of CHEST (November 2004), Demers1 related an anecdote regarding a young female patient with an acute drug overdose who was receiving mechanical ventilatory support and in whom a delayed arterial blood gas measurement revealed a Pco2 less than half the normal value. We are told that a repeat blood gas measurement 2 h after halving the respiratory rate (and therefore the minute ventilation) was basically unchanged and that only after an additional 7 h was the arterial Pco2 in the mid-40 mm Hg range. Full-Text PDF