Brazilian Journal of Anesthesiology
Brazilian Journal of Anesthesiology
Original Investigation

Comparative study between suprasternal and apical windows: a user-friendly cardiac output measurement for the anesthesiologist

Estudo comparativo entre janela supraesternal e apical: uma medida de débito cardíaco acessível ao anestesista

Rafaela Souto e Souza, Wendhell Barros de Melo, Claudia Maria Vilas Freire, Walkiria Wingester Vilas Boas

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Transthoracic echocardiography is a safe and readily available tool for noninvasive monitoring of Cardiac Output (CO). The use of the suprasternal window situated at the sternal notch can be an alternative approach for estimating blood flow. The present study aimed to compare two methods of CO calculation. We compared the descending aorta Velocity-Time Integral (VTI) measurement from the suprasternal window view with the standard technique to determine CO that uses VTI measurements from the LVOT (Left Ventricular Outflow Tract) view. We also aimed to find out whether after basic training a non-echocardiographer operator can obtain reproducible measurements of VTI using this approach.

In the first part of the study, 26 patients without known cardiovascular diseases were evaluated and VTI data were acquired from the suprasternal window by a non-echocardiographer and an echocardiographer. Next, 17 patients were evaluated by an echocardiographer only and VTI and CO measurements were obtained from suprasternal and apical windows. Data were analyzed using the Bland and Altman method (BA), correlation and regression.

We found a strong correlation between measurements obtained by a non-expert and an expert echocardiographer and detected that an inexperienced trainee can acquire VTI measurements from the suprasternal window view. Regarding agreement between CO measurements, data obtained showed a positive correlation and the Bland and Altman analysis presented a total variation of 38.9%.

Regarding accuracy, it is likely that TTE (Transthoracic Echocardiogram) measurements of CO from the suprasternal window view are comparable to other minimally invasive techniques currently available. Due to its user-friendliness and low cost, it can be a convenient technique for obtaining perioperative hemodynamic measurements, even by inexperienced operators.


Non-invasive monitoring;  Echocardiogram;  Cardiac output;  Doppler ultrasonography



O ecocardiograma transtorácico tem sido considerado uma ferramenta segura e facilmente disponível para monitorização não invasiva do DC. A utilização da fúrcula esternal através da janela supraesternal pode ser uma alternativa para cálculo de fluxo sanguíneo. O objetivo deste trabalho é comparar as medidas do VTI na aorta descendente através da janela supraesternal com as medidas da VTI do fluxo na VSVE, normalmente utilizada para medir DC. Também pretende-se determinar se um avaliador não ecocardiografista consegue obter medidas reprodutíveis de VTI por esse método após treinamento básico.


No primeiro tempo do estudo, foram avaliados 26 pacientes sem doenças cardiovasculares conhecidas e coletados dados de VTI na janela supraesternal por avaliador não experiente e por ecocardiografista. No segundo, foram avaliados 17 pacientes pelo ecocardiografista e coletados dados de VTI e DC nas janelas supraesternal e apical. Os dados foram analisados pelo método de Bland e Altman, correlação e regressão.


Houve forte correlação entre as medidas realizadas por avaliador não especialista e ecocardiografista, identificando que treinador não experiente pode realizar medidas de VTI supraesternal. Em relação à concordância entre os DC, os dados obtidos mostraram que os valores apresentaram correlação positiva e o BA apresentou variação total de 38,9%.


É provável que as medidas do DC por ETT na janela supraesternal se assemelhem a técnicas minimamente invasivas disponíveis no mercado com relação a precisão. Devido à sua praticidade e baixo custo, pode ser uma técnica conveniente para obtenção de medidas hemodinâmicas no perioperatório, inclusive por examinadores não experientes.


Monitorização não invasiva; Ecocardiograma; Débito cardíaco; Ultrassonografia Doppler


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