Feasibility of common carotid artery point of care ultrasound in cardiac output measurements compared to invasive methods

Abstract

Background Cardiac output (CO) measurement in the intensive care unit (ICU) requires invasive devices such as the pulmonary artery (PA) catheter or arterial waveform pulse contour analysis (PCA). This study tests the accuracy and feasibility of point of care ultrasound (POCUS) of the common carotid artery to estimate the CO non-invasively and compare it to existing invasive CO measurement modalities. Methods Patients admitted to the surgical and cardiothoracic ICU in a tertiary university-affiliated academic center during a 4-month period, with invasive hemodynamic monitoring devices for management, were included in this cohort study. Common carotid artery POCUS was performed to measure the CO and the results were compared to an invasive device. Results Intensivists and ICU fellows, using ultrasound of the common carotid artery, obtained the CO measurements. Images of the Doppler flow and volume were obtained at the level of the thyroid gland. Concurrent CO measured via invasive devices was recorded. The patient cohort comprised 36 patients; 52 % were females. The average age was 59 ± 13 years, and 66 % were monitored via PCA device and 33 % via PA catheter. Intraclass correlation coefficient (ICC) analysis demonstrated almost perfect correlation (0.8152) between measurements of CO via ultrasound vs. invasive modalities. The ICC between PO-CUS and the invasive measurement via PCA was 0.84 and via PA catheter 0.74, showing substantial agreement between the ultrasound and both invasive modalities. Conclusions Common carotid artery POCUS offers a non-invasive method of measuring the CO in the critically ill population.Keywords Cardiac output Á Ultrasound Á Carotid doppler Á Pulmonary artery catheter Á Pulse contour analysis Á Point of care ultrasound Abstract Background La misurazione della gittata cardiaca (CO) in Unità di Terapia Intensiva (ICU) richiede dispositivi invasivi come il cateterismo dell'arteria polmonare (PA) o l'analisi dell'onda dell'impulso arterioso (PCA). Questo studio si propone di valutare l'accuratezza e la fattibilità dell'ecografia (POCUS) della carotide comune per stimare la CO in modo non invasivo e confrontarla con le modalità esistenti di misurazione della CO effettuate in maniera invasiva. Metodi I pazienti ricoverati in terapia intensiva chirurgica e cardiotoracica in un centro accademico, affiliato con l'università, nel corso di un periodo di quattro mesi, sottoposti a dispositivi di monitoraggio emodinamico invasivo sono stati inclusi in questo studio. E' stata eseguita l'ecografia dell'arteria carotide comune per misurare la CO ed i risultati sono stati confrontati con una tecnica invasiva. Risultati Medici di terapia intensiva e borsisti, utilizzando l'ecografia della carotide comune, hanno ottenuto le misurazioni della CO. Immagini del flusso Doppler e di volume sono state ottenute a livello della ghiandola tiroidea. Contemporaneamente è è stata registrata la CO mediante dispositivi invasivi. Il gruppo era costituito da 36 Ultrasound (2015) 18:127-133 DOI 10.1007 pazien...

Common Carotid Artery Sonography Versus Transthoracic Echocardiography for Cardiac Output Measurements in Intensive Care Unit Patients

“…Intraclass correlation coefficients between TTE and carotid cardiac output are shown in Table . The interpretation of ICC values on the agreement levels between TTE and carotid cardiac output followed the standard of a previous study . Overall, there was no statistically significant difference between the cardiac output measurements, and the ICC between them indicated moderate agreement.…”

“…Moreover, ICU patients often have difficulties in positioning because of comas, neck injuries, and cervical spine immobilization collars, as well as interfering incisions and wound dressings, which make it even harder to get optimal cardiac windows. Thus, several studies have tried to use common carotid artery Doppler examination as an alternative for measuring cardiac function . In 2013, Marik et al reported that when passive leg raising was performed to predict volume responsiveness, there was a strong correlation between the percent change in the stroke volume index and the concomitant percent change in carotid blood flow ( r = 0.59; P = .0003).…”

“…Sonographic measurements were conducted according to a previous study . Briefly, all patients were placed in the semi‐Fowler position at 30° with the head of the patient rotated away from the ultrasound operator.…”

“…The volume flow was automatically calculated by the ultrasound machine, and cardiac output was calculated by the following formula: cardiac output = carotid Doppler flow volume × 10 . For patients who had bilateral common carotid artery measurements, carotid cardiac output was calculated as the mean of the left and right carotid cardiac output values.…”

“…However, as most intensivists are not professional sonographers or sonologists, they often face difficulties in measuring cardiac output by flow velocity through the left ventricular outflow tract, especially when dealing with suboptimal cardiac windows due to positioning difficulties, interfering incisions, or wound dressings, which are common conditions in ICU patients. Thus, several studies have focused on this problem and found that common carotid artery blood flow and Doppler waveforms were related to cardiac function, suggesting a feasible alternative for cardiac output measurement. However, other studies reported a weak relationship between them and suggested that carotid blood flow could not be used to provide noninvasive estimates of the cardiac index, ejection fraction, stroke volume, or cardiac output .…”