UltraSound cardiac output monitoring in volemic status evaluation in emergency department
LEGGI ARTICOLO COMPLETO:
UltraSound cardiac output monitoring in volemic status evaluation in emergency department
Claudia CARELLI 1 *, Riccardo CANDIDO 2, Anita COSTANZO 2, Giovanna CRISTIANO 2, NicolaDE LUCA 3, Gianluca GIACONIA 4, Carmela MANZO 4, Lucrezia PAGLIUCA 2, Angela RUSSO 2, Christian TESTA 1, Mario GUARINO 2
1Emergency School, University of Naples “Federico II”, Naples, Italy; 2Emergency Department, C.T.O. Hospital, Naples, Italy; 3Department of Advanced Biomedical Sciences, University of Naples “Federico II”, Naples, Italy; 4Clinical Engineering, A.O.R.N. Ospedali dei Colli, Naples, Italy
*Corresponding author: Claudia Carelli, Emergency School, University of Naples “Federico II”, Via Sergio Pansini 5, 80131Naples, Italy. E-mail: cl.carelli@hotmail.com
ABSTRACT
Nowadays, a wide range of hemodynamic monitoring systems is available, each having its own advantages and limitations. A recently introduced method is represented by the USCOM (UltraSound Cardiac Output Monitor; USCOM™ Pty Ltd, Coffs Harbour, Australia), a non-invasive, reproducible monitoring system with a rapid learning curve, which allows to study the blood flow at the level of the aortic and pulmonary valve. In this short report, the USCOM device is adopted to study two opposite clinical cases: a dehydrated patient and a pulmonary oedema-affected one.
(Cite this article as: Carelli C, Candido R, Costanzo A, Cristiano G, De Luca N, Giaconia G, et al. UltraSound cardiac output monitoring in volemic status evaluation in emergency department. Ital J Emerg Med 2023;12:47-50. DOI: 10.23736/S2532-1285.23.00164-7)
Key words: Ultrasonography; Hemodynamic monitoring; Cardiac output.
In emergency departments (ED) it is necessary to perform a non-invasive and accurate evaluation of the hemodynamic parameters to screen patients and monitor the therapeutic response quickly. Today a wide variety of hemodynamic monitoring systems are available, but pulmonary artery catheterization (PAC) remains the gold standard for assessing cardiac output (CO). However, the Swan-Ganz catheter placement is complicated because it requires time and specific skills, besides not being risk-free. For these reasons, it is necessary to carry out a risk/benefit assessment based on the objectives set. A non-invasive and recently introduced hemodynamic monitoring system, applied in our clinical cases, is the USCOM (UltraSound Cardiac Output Monitor; USCOM™ Pty Ltd, Coffs Harbour, Australia) which allows to evaluate the CO using ultrasound generated by a Doppler CW probe applied on the suprasternal notch (for trans-aortic flow) or at the 3rd-4th left intercostal space (for trans-pulmonary flow) (Figure 1).
Figure 1.—Data acquisition via USCOM.
The monitor shows the velocity-time ratio of the blood ejected from the valve and the CO is calculated considering the valve surface area, evaluated by the device based on anthropometric data (age, gender, weight, and height), velocity-time integral and heart rate. Therefore, a quick overview of the main procedures in use is necessary to know the pros and cons for each of them, to conscientiously choose the device that best suits your needs. In general, the methods are divided into two categories based on the degree of invasivity. Invasive systems can exploit two different methods, sometimes in combinations in the same device:
• thermodilution or dilution of an indicator. Thermodilution involves the administration a bolus at a constant volume and at a temperature lower than that of the body into a central vein. The temperature variation is perceived downstream by an arterial catheter with thermistor which allows the evaluation of the stroke volume (SV) by measuring the speed of thermal decay. This method makes possible to evaluate CO, pulmonary capillary, and central venous pressure (as in the PAC) or intrathoracic volumes (as in the PiCCO), but it doesn’t allow continuous monitoring and results are unreliable in case of cardiac shunts, severe tricuspid regurgitation or mistakes in the execution of the procedure;
• pulse contour analysis, which allows beat-to-beat determination of SV through blood pressure waveform analysis. This method, even if it allows continuous monitoring, provides few hemodynamic information and is not very reliable in the case of rapid changes in the vascular tone or a low-quality pressure signal, severe arrhythmias, significant aortic insufficiency, aneurysms of the aorta.
In the context of non-invasive methods, we find:
• bioreactance, which provides an estimate of the blood flow via measuring the pulsatile time delay (i.e., “phase shift”) among recorded voltage signals with four electrodes located on the chest wall. This method allows to measure the SV in a continuous and non-invasive way, but it has high consumable costs, external PMKs can create interference and results are unreliable in case of severe aortic insufficiency or anatomical anomalies of the thoracic aorta.
• finally, there are methods that exploit ultrasound such as transesophageal echocardiogram and USCOM. The latter provides to study the flow that crosses the aortic and pulmonary valve allowing to estimate the cardiac output and the parameters of preload, afterload, cardiac inotropism and systemic perfusion. However, this method is operator dependent and, in case of stenosis and/or insufficiencies at the aortic valve, tends to overestimate the CO.
Clinical series
Case 1
A 90-year-old woman arrived in the ED for a reported state of confusion. In the anamnesis we learnt that the lady had a persistent fever for about 20 days, resistant to paracetamol, for which she had already made several antibiotic cycles without improvement. At the clinical evaluation, the patient was soporous (GCS 7 – E1V1M5). The vital parameters were normal, except for the hypoxemia highlighted at the entrance ABG for which a VM with FiO2at 40% had been applied. Furthermore, the ABG had shown an increase of lactates (3 mmol/L) and hypernatremia (>180 mmol/L), confirming a condition of severe dehydration with a water deficit estimated to be 6.23 liters; chest CT showed an inflammatory process. Once the diagnosis of “sepsis of pulmonary origin in a patient with severe dehydration” was reached, therapy with antibiotics and continuous infusion of hypotonic solution was undertaken, for a total of 2400 cc/day. Given the critical condition, we performed a hemodynamic evaluation using USCOM before and after the fluid infusion. The data obtained highlighted the reduced cardiac contractility (represented by the SMII and VPK parameters) and the lack of improvement in DO2 and CO after the fluid infusion that had caused a slight increase of the preload index (represented by the FTc) with a progressive reduction of the high resistances (Table I).
Case 2
A 71-year-old man presented to the ED for worsening dyspnoea in the last 7 days with appearance of oedema in the lower limbs. In the anamnesis, the patient reports a permanent AF and that in the last echocardiographic examination EF was on the lower limits. The entrance ABG highlighted a condition of severe hypoxemia, for which a VM with FiO2 at 60% was placed. At the clinical evaluation of the chest, rales with widespread wheezing were found with a reduction of the right basal vesicular murmur, confirmed by the echofast that showed diffuse B lines with a right basal pleural effusion, in addition to a dilated and hypo-collapsing IVC. Blood chemistry tests revealed an elevated ProBNP, reaching the diagnosis of “heart failure” for which therapy with diuretics (for a total of 160 mg furosemide IV) and CPAP was started. Once the clinical conditions improved, we performed a hemodynamic evaluation using USCOM which confirmed cardiac contractility on the lower limits, while the preload parameter was returned to values slightly lower than normal (Table I).
Discussion
In our clinical series, the choice of USCOM as monitoring system was guided by our necessity for non-invasiveness, to obtain easily and quickly repeatable information that allows us to know a trend of their hemodynamic status, in absence of consumables and, at the same time, provide information on the status of preload, afterload, inotropism and CO. The introduction of USCOM into clinical practice is relatively recent (2005), however, despite more than 15 years have passed, its use is relatively limited and still in an exploratory phase. Several studies in the literature report numerous analyses to compare the performance of this method with other approaches validated in clinical practice. For example, in (Chong and Peyton)1 the authors carry out a meta-analysis to evaluate the performance of USCOM in terms of precision and accuracy compared to thermodilution and other minimally invasive methods, presenting comparable results. However, although the results reported in the study are encouraging, a broader validation including more case series is still needed. In (Lelyveld-Haas et al.),2 the Authors performed a prospective observational study of the performance of the device compared to the PAC. This study compares the results obtained from 263 measurements obtained with the USCOM and PAC, showing a discrete correlation between the two techniques (r=0.80), although, compared with the gold standard method, CO values were lower of 12% in USCOM measurements (systematic error) and with a random error of 17% (coefficient of variation). More promising results were obtained, however, from (Hoster et al.)3 in which the authors compared the performance of USCOM respect to PiCCO. In particular, the prospective observational study proposed by the Authors compares CO measurement with the two methods in 70 septic patients treated with catecholamines and mechanical ventilation, obtaining comparable results (r=0.89).
Conclusions
In the field of non-invasive hemodynamic monitoring techniques, USCOM is an interesting alternative to traditional methods for analyzing the hemodynamic of critically ill patients in an easy, reproducible, non-invasive way, also considering the rapid learning curve (Hodgson et al.)4 compared to other methods. This makes possible to evaluate its use in patient monitoring even by nursing staff after a short training. In fact, in a prospective observational study proposed by (Corley et al.)5 the results of the CO obtained by nurse using the USCOM and PAC were compared: the results were comparable (bias -0.34±0.52 L/min) and, while in the case of USCOM the data were obtained in an average time of 10 min, the time required between the decision to position the PAC and the first result varied from 45 to 120 min. However, given its recent introduction and the variety of opinions in today’s scientific literature, further studies are needed considering a larger sample and case history.
References
1. Chong SW, Peyton PJ. A meta-analysis of the accuracy and precision of the ultrasonic cardiac output monitor (USCOM). Anaesthesia 2012;67:1266–71. PubMedhttps://doi.org/10.1017/S0265021508004882
3. Horster S, Stemmler HJ, Strecker N, Brettner F, Hausmann A, Cnossen J, et al. Cardiac Output Measurements in Septic Patients: Comparing the Accuracy of USCOM to PiCCO. Crit Care Res Pract2012;2012:270631. PubMedhttps://doi.org/10.1177/1751143715619186
5. Corley A, Barnett AG, Mullany D, Fraser JF. Nurse-determined assessment of cardiac output. Comparing a non-invasive cardiac output device and pulmonary artery catheter: a prospective observational study. Int J Nurs Stud 2009;46:1291–7. <a data-cke-saved-href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=19423107&dopt=Abstract%20target=" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=19423107&dopt=Abstract%20target=" _blank"="" style="text-decoration: none; color: rgb(0, 102, 0); font-weight: bold;">PubMed https://doi.org/10.1016/j.ijnurstu.2009.03.013
Conflicts of interest.—The authors certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript.
Authors’ contributions.—Claudia Carelli and Mario Guarino have given substantial contributions to the study conception and design; Claudia Carelli and Christian Testa contributed to the data acquisition, analysis and interpretation; all authors have participated to the manuscript draft, Mario Guarino revised it critically. All authors read and approved the final version of the manuscript.
History.—Manuscript accepted: January 23, 2023. - Manuscript received: December 17, 2022.