Noninvasive Continuous Cardiac Output Research Articles

Occurrence of Low Cardiac Index During Normotensive Periods in Cardiac Surgery: A Prospective Cohort Study Using Continuous Noninvasive Cardiac Output Monitoring.

Continuous cardiac output monitoring is not standard practice during cardiac surgery, even though patients are at substantial risk for systemic hypoperfusion. Thus, the frequency of low cardiac output during cardiac surgery is unknown. We conducted a prospective cohort study at a tertiary medical center from July 2021 to November 2023. Eligible patients were ≥18 undergoing isolated coronary bypass (CAB) surgery with the use of cardiopulmonary bypass (CPB). Cardiac output indexed to body surface area (CI) was continuously recorded at 5-second intervals throughout surgery using a US Food and Drug Administration (FDA)-approved noninvasive monitor from the arterial blood pressure waveform. Mean arterial blood pressure (MAP) and central venous pressure (CVP) were also analyzed. Low CI was defined as <2 L/min/m2 and low MAP as <65 mm Hg. We calculated time with low CI for each patient for the entire surgery, pre-CPB and post-CPB periods, and the proportion of time with low CI and normal MAP. We used Pearson correlation to evaluate the relationship between CI and MAP and paired Wilcoxon rank sum tests to assess the difference in correlations of CI with MAP before and after CPB. In total, 101 patients were analyzed (age [standard deviation, SD] 64.8 [9.8] years, 25% female). Total intraoperative time (mean [SD]) with low CI was 86.4 (62) minutes, with 61.2 (42) minutes of low CI pre-CPB and 25.2 (31) minutes post-CPB. Total intraoperative time with low CI and normal MAP was 66.5 (56) minutes, representing mean (SD) 69% (23%) of the total time with low CI; 45.8 (38) minutes occurred pre-CPB and 20.6 (27) minutes occurred post-CPB. Overall, the correlation (mean [SD]) between CI and MAP was 0.33 (0.31), and the correlation was significantly higher pre-CPB (0.53 [0.32]) than post-CPB (0.29 [0.28], 95% confidence interval [CI] for difference [0.18-0.34], P < .001); however, there was substantial heterogeneity among participants in correlations of CI with MAP before and after CPB. Secondary analyses that accounted for CVP did not alter the correlation between CI and MAP. Exploratory analyses suggested duration of low CI (C <2 L/min/m2) was associated with increased risk of postoperative acute kidney injury (odds ratios [ORs] = 1.09; 95% CI; 1.01-1.13; P = .018). In a prospective cohort of patients undergoing CAB surgery, low CI was common even when blood pressure was normal. CI and MAP were correlated modestly. Correlation was higher before than after CPB with substantial heterogeneity among individuals. Future studies are needed to examine the independent relation of low CI to postoperative kidney injury and other adverse outcomes related to hypoperfusion.

Monitoring CO2 kinetics as a marker of cardiopulmonary efficiency.

To describe current and near future developments and applications of CO2 kinetics in clinical respiratory and cardiovascular monitoring. In the last years, we have witnessed a renewed interest in CO2 kinetics in relation with a better understanding of volumetric capnography and its derived parameters. This together with technological advances and improved measurement systems have expanded the monitoring potential of CO2 kinetics including breath by breath continuous end-expiratory lung volume and continuous noninvasive cardiac output. Dead space has slowly been gaining relevance in clinical monitoring and prognostic evaluation. Easy to measure dead space surrogates such as the ventilatory ratio have demonstrated a strong prognostic value in patients with acute respiratory failure. The kinetics of carbon dioxide describe many relevant physiological processes. The clinical introduction of new ways of assessing respiratory and circulatory efficiency based on advanced analysis of CO2 kinetics are paving the road to a long-desired goal in clinical monitoring of critically ill patients: the integration of respiratory and circulatory monitoring during mechanical ventilation.

Comparison of parameter types for the calibration of noninvasive continuous cardiac output monitoring of patients undergoing lumbar spinal surgery in the prone position.

Cardiac output (CO) decreases on reversing the patient's position to the prone position. Estimated continuous cardiac output (esCCO) systems can noninvasively and continuously monitor CO calibrated by patient information or transesophageal echocardiogram (TEE). To compare the accuracy, precision, and trending ability of two calibration methods of CO estimation in patients in prone position. The CO estimates calibrated by TEE (esT) and patient information (esP) of 26 participants were included. CO was collected at four time points. The accuracy and precision of agreement were evaluated using the Bland-Altman method. A four-quadrant plot was used for trending ability analysis. The bias between esP and TEE and between esT and TEE was 0.2594 L/min (95% limits of agreement (LoA): -1.8374 L/min to 2.3562 L/min) and 0.0337 L/min (95% LoA: -0.7381 L/min to 0.8055 L/min), respectively. A strong correlation was found between ΔesP and ΔTEE (p< 0.001, CCC = 0.700) and between ΔesT and ΔTEE (p< 0.001, CCC = 0.794). The concordance rates between ΔesP and ΔTEE and between ΔesT and ΔTEE were 91.9% and 97.1%, respectively. Despite limited accuracy and precision, esP showed acceptable trending ability. The trending ability of esCCO calibrated by the reference TEE value was comparable with that of TEE.

The Value of Noninvasive Continuous Cardiac Output Monitoring in Assessment of Hemodynamic Status in Critically Ill Children

Access to reliable, rapid, and continuous hemodynamic monitoring parameters is essential for early diagnosis and prompt treatment of hemodynamic disorders in critically ill children. The aim of this observational study was to compare the accuracy of continuous non-invasive cardiac output monitoring (NICCOMO) device data with transthoracic echocardiography (TTE) and inferior vena cava (IVC) ultrasound findings in assessing cardiac output (C.I), circulatory fluid adequacy, and finally Determination of hemodynamic status in patients with Critical conditions hospitalized in the Pediatric Intensive Care Unit (PICU). In this observational study, forty-four critically ill children that were admitted to PICU were evaluated. We used NICCOMO, TTE, and IVC ultrasonography at the same time in critical patients. The association between NICCOMO parameters and echocardiogram cardiac index and IVC quality in ultrasound is compared. The agreement between CI measured by TTE and NICCOMO was assessed using the Bland-Altman analysis method. NICCOMO is not a reliable instrument for determining CI in children with an unstable hemodynamic status. However, the parameters of this device are reliable in assessing the patient's hemodynamic status. Findings showed that 90% of patients in the normal hemodynamic state in NICCOMO have SVR. I in the normal range (P&lt;0.001), and all cases in hypervolemic state had volume overload IVC in ultrasonography analysis. Noninvasive continuous cardiac output monitoring could be used to estimate unstable patients’ hemodynamic status in the initial stages for making timely treatment-related decisions, but its use for accurate cardiac index measurement is not reliable in all cases.

Non-invasive continuous cardiac output monitoring in infants with hypoxic ischaemic encephalopathy

ObjectiveTo describe early, continuous, non-invasive measures of cardiac output (CO) and evolution over time in infants with hypoxic-ischaemic encephalopathy (HIE).Study designProspective observational study of 44 infants with HIE (23 mild, 17 moderate, 4 severe) and 17 term controls. Infants with HIE had non-invasive CO monitoring (NICOM) continuously in the neonatal unit. Term controls had NICOM recorded at 6 and 24 h. A mixed-modelling approach was used to assess change in CO over time by group.ResultsInfants with moderate HIE have significantly lower CO than the mild group at all timepoints (10.7 mls/kg/min lower, 95% CI:1.0,20.4, p = 0.03) which increases over time, driven by a gradual increase in stroke volume (SV). CO increased further during rewarming predominantly due to an increase in HR.ConclusionTH has a significant impact on HR but SV appears largely unaffected. NICOM may provide a non-invasive, continuous, low-cost alternative to monitoring CO in infants with HIE however further research is warranted.

Comparing cardiac output measurements using electrical cardiometry versus phase contrast cardiac magnetic resonance imaging

BackgroundThere is a growing interest in using non-invasive electrical cardiometry (EC) for continuous cardiac output (CO) measurements in neonates and children. There is a lack of sufficient data to validate CO measured by EC with currently accepted noninvasive techniques such as cardiac MRI (CMRI) in children. ObjectivesTo assess the degree of agreement between CO measured by EC and CMRI in children. We hypothesized that there is a good degree of agreement between CO measured by EC and CMRI in children. MethodsA retrospective chart review was performed to include patients who had noninvasive CO measured using EC (ICON®) and CMRI at our children's hospital between Feb 2019 and May 2020. Anthropometric, clinical and CO data were collected and CMRI parameters such as flow measurements in the aorta and pulmonary artery were analyzed. Data was analyzed using a Bland-Altman plot to compare the agreement between the CO obtained by EC vs. CMRI in this cohort of patients. ResultsA total of 52 patients with cardiac disease who had data available from CMRI and ICON® were included. The median (IQR) age was 174 (99,201) months and male: female ratio was 1.2:1. A total of 34/52 (60 %) patients had congenital heart disease and 22 had history of surgical interventions prior to noninvasive CO measurements. The Bland-Altman analysis for CO values by both EC and CMRI produced a mean bias (SD) of 0.12 (2.73) l/min for ICON® and the 95 % limits of agreement were −5.229 to 5.473 l/min. The precision error was only 1.86 %. The Bland- Altman plot for reproducibility for CO values by EC produced a mean bias (SD) of 0.15 (0.41) l/min with limits of agreement of −0.66 to 0.97 l/min. The percentage error was 2.34 %. ConclusionsIn our cohort of cardiac patients, there was a good degree of agreement between noninvasive CO as measured by Electric Cardiometry and Cardiac MRI.

Perioperative Continuous Noninvasive Cardiac Output Monitoring in Cardiac Surgery Patients by a Novel Capnodynamic Method

To test the clinical performance of a novel continuous noninvasive cardiac output (CO) monitoring based on expired carbon dioxide kinetics in cardiac surgery patients. A prospective feasibility pragmatic clinical study. A single-center, large community hospital. Thirty-two patients undergoing cardiac surgery were studied during the intraoperative (before cardiopulmonary bypass) and postoperative (in the intensive care unit before extubation) periods. CO was measured simultaneously by the continuous capnodynamic method and by transpulmonary thermodilution during changes in the patient's hemodynamic and/or respiratory conditions. The current recommended comparative statistics for CO measurement methods were analyzed, including bias, precision, and percentage error obtained from Bland-Altman analysis, and concordance between methods obtained from the four-quadrant plot analysis to evaluate the trending ability. Bias ± limits of agreement and percentage error were -0.6 (-1.9 to +0.8; 95% CI of 3.73-5.25) L/min and 31% (n=147 measurements) for the intraoperative period, -0.8 (-2.4 to +0.9; 95% CI of 3.03-5.21) L/min and 41% (n=66) for the postoperative period, and -0.6 (-2.1 to +0.8; 95% CI of 3.74-5.00) L/min and 34% (n=213) for the pooled data. The trending analysis obtained a concordance of 82% (n=65) for the intraoperative and 71% (n=24) for the early postoperative periods. Aggregation of both data sets gave a concordance of 79% (n=89). The continuous capnodynamic method was reliable and in good agreement with the reference method, and had an accuracy and trending ability good enough tomake it a possible future alternative for hemodynamic monitoring in the studied population of elective adult cardiac surgery patients.

Non-invasive continuous cardiac output monitoring in thoracic cancer surgery

BACKGROUND Patients scheduled for thoracic cancer surgery are eligible for goal-directed fluid therapy, but cardiac output monitoring remains challenging in that specific setting. OBJECTIVE We aimed to compare cardiac output as measured with chest bioreactance with that measured by calibrated pulse contour analysis; the hypothesis being that both methods would be interchangeable. DESIGN A prospective monocentre observational study. SETTING A tertiary university hospital. PATIENTS Fifty adult patients undergoing thoracic cancer surgery over a one year period. MAIN OUTCOME MEASURES Simultaneous measurements of cardiac index (CI) with bioreactance (CI-NICOM) and arterial pulse contour analysis calibrated by transthoracic echocardiography (CI-PCA) were performed at eight pre-specified intra-operative time points and following fluid challenge and/or vasoactive agents. Relationships between absolute values and changes in CI were assessed by linear regression. Interchangeability was tested with Bland–Altman analysis and percentage error calculation. A four quadrant plot was used to evaluate trending ability. RESULTS There was a significant difference between CI-PCA and CI-NICOM: 2.4 ± 0.8 (range: 0.9 to 5.8) l min−1 m−2 vs. 2.9 ± 0.9 (range: 0.9 to 7.2) l min−1 m−2, respectively (P &lt; 0.001). A positive relationship was found between both techniques: y = 0.29x + 2.19; r 2 = 0.08 (P &lt; 0.001). Taking CI-PCA as the reference method, there was a systematic overestimation of CI-NICOM by 21% (0.5 l min−1 m−2) and limits of agreement were large: -2.49 to 1.47 l min−1 m−2. The percentage error was 77% and concordance rates were 75 and 70% with and without an exclusion zone of 0.5 l min−1 m−2. CONCLUSION Chest bioreactance is feasible and well tolerated in patients undergoing thoracic surgery for cancer. When compared with calibrated PCA over a wide range of CI values, the technique is moderately correlated, not interchangeable, and provides moderate trending ability. TRIAL REGISTRATION NCT04251637.

Maternal haemodynamics during labour epidural analgesia with and without adrenaline.

Labour is one of the most painful experiences in a woman's life. Epidural analgesia using low-concentration local anaesthetics and lipophilic opioids is the gold standard for pain relief during labour. Pregnancy in general, particularly labour, is associated with changes in maternal haemodynamic variables, such as cardiac output and heart rate, which increase and peak during uterine contractions. Adrenaline is added to labour epidural solutions to enhance efficacy by stimulating the α2-adrenoreceptor. The minimal effective concentration of adrenaline was found to be 2μgmL-1 for postoperative analgesia. The addition of adrenaline may also produce vasoconstriction, limiting the absorption of fentanyl into the systemic circulation, thereby reducing foetal exposure. However, adrenaline may influence the haemodynamic fluctuations, possibly adding to the strain on the circulatory system. The aim of this study was to compare the haemodynamic changes after application of labour epidural analgesia with or without adrenaline 2μgmL-1. This was a secondary analysis of a single-centre, randomised double-blind trial. Forty-one nulliparous women in labour requesting epidural analgesia were randomised to receive epidural solution of bupivacaine 1mgmL-1, fentanyl 2μgmL-1 with or without adrenaline 2μgmL-1. The participants were monitored using a Nexfin CC continuous non-invasive blood pressure and cardiac output monitor. The primary outcomes were changes in peak systolic blood pressure and cardiac output during uterine contraction within 30min after epidural activation. The effect of adrenaline was tested statistically using a linear mixed-effects model of the outcome variables' dependency on time, adrenaline, and their interaction. After excluding three patients due to poor data quality and two due to a malfunctioning epidural catheter, 36 patients (18 in each group) were analysed. The addition of adrenaline to the solution had no significant effect on the temporal changes in peak systolic blood pressure (p=0.26), peak cardiac output (0.84), or heart rate (p=0.91). Furthermore, no significant temporal changes in maternal haemodynamics (peak systolic blood pressure, p=0.54, peak cardiac output, p=0.59, or heart rate p=0.55) were associated with epidural analgesia during 30min after epidural activation in both groups despite good analgesia. The addition of 2μgmL-1 adrenaline to the epidural solution is not likely to change maternal haemodynamics during labour.

Electrical velocimetry (ICON cardiometry) assessment of hemodynamic changes associated with different inflation pressures during pediatric thoracoscopic surgery: a pilot study

Background Advances in endoscopic equipment and techniques have led to the use of minimally invasive thoracic surgery in an increasing number of pediatric surgical procedures. Logically, thoracoscopic surgery and anesthesia can induce significant physiologic changes; here comes the importance of an accurate, noninvasive cardiac output (CO) monitor for early diagnosis and management for any significant complications.Aims This study aimed to assess the effect of different intrathoracic pressures (ITP; insufflation pressures 4, 5, and 6 mmHg) during thoracoscopic surgeries in neonates and infants on hemodynamics using electrical velocimetry (ICON) as a noninvasive monitoring technique.Patients and methods This prospective pilot study was conducted in Abu El-Reesh Children’s Hospital, Kasr Al-Ainy Hospital, Faculty of Medicine, Cairo University, from November 2019 to January 2020. After obtaining ethical committee approval (D-6-2019) and registering at www.clinicaltrials.gov with the number NCT04131699, and after obtaining the consent of parents/legal guardians, 12 neonates and infants who presented for thoracoscopic surgery and met our selection criteria were included in the study. After standard premedication, monitoring, and anesthesia induction, for electrical velocimetry, an ‘ICON CARDIOTRONIC, OSYPKA MEDICAL’ continuous noninvasive CO monitor was attached to the patients according to the manufacturer’s instructions in neonates and infants. All patients’ data, including sex, height, and weight, were entered into the device, which estimated cardiovascular parameters at a 20-beat moving average recorded every 10 s. Cardiac index, CO, stroke volume, noninvasive arterial blood pressure, and heart rate readings had been taken in every patient. Records were taken before inflation of the chest as a baseline reference, 1 min after inflation of the chest as the ITP reaches 4 mmHg, then the ITP was increased to 5 mmHg, and the readings were taken after an extra 1 min. Finally, the ITP was increased to 6 mmHg, and the readings were taken after an additional 1 min.Results A total of 14 patients were screened for eligibility; of them, two patients were excluded for not meeting the inclusion criteria, and 12 patients were included. The median (interquartile range) age of patients was 4.5 (3–28) days. Sex distribution was equal (six males and six females). The cardiac index showed no significant increase with raising the pleural pressure (PP) by CO2 insufflation and postdeflation in comparison with baseline (preinsufflation). The CO showed no significant increase with raising the PP by CO2 insufflation in comparison with baseline (preinsufflation). Mean arterial blood pressure showed no significant change with gradual increase in PP and after deflation in comparison with preinflation readings; however, heart rate showed significant decrease after deflation in comparison with baseline (preinsufflation).Conclusion Hemodynamic stability was maintained during thoracoscopic surgery in neonates as measured by ICON. Further studies including systemic vascular resistance need to be done to give more explanation about hemodynamic affection during positive PP inflation. Moreover, different age groups, different patients’ positions, and patients with cardiac and pulmonary lesions need to be included to assess the various effects of pleural insufflation on these populations.

Effect of Endovascular Treatment on Systemic Vascular Resistance in Patients with Lower-Limb Peripheral Artery Disease.

Objective: Endovascular treatment (EVT) for lower-limb peripheral artery disease patients reduces blood pressure (BP) and improves prognosis. This study retrospectively examined hemodynamics during EVT to clarify the mechanism.Materials and Methods: Systemic vascular resistance (SVR) was measured using a noninvasive continuous cardiac output monitoring system during EVT. Furthermore, ankle brachial index was measured before and after EVT.Results: The study included 88 lesions of 56 patients (hypertension in 98%). SVR significantly decreased from 2409.1±746.8 dynes·s·cm−5 to 2033.7±635.0 dynes·s·cm−5 (p<0.0001). The difference in SVR before and after EVT was significantly greater in the Fontaine IV group than in the Fontaine IIa group (554.7±406.6 dynes·s·cm−5 vs. 312.9±245.7 dynes·s·cm−5, p=0.0151). The change in SVR was correlated with a change in mean BP in the upper limb (p=0.0026). When the change in pressure gradient between the upper limb and the diseased lower limb was large, mean BP of the upper limb significantly decreased (p=0.0022).Conclusion: EVT can reduce SVR and BP by canceling the pressure gradient between central BP and diseased lower-limb BP.

Postoperative continuous non-invasive cardiac output monitoring on the ward: a feasibility study

Postoperative hypotension is common (occurring in one third of patients) and is associated with worse clinical outcomes. The LiDCO CNAP (continuous non-invasive arterial pressure) device measures haemodynamics but has not been widely adopted in ward environments. Improved early detection of hypotension by CNAP might guide interventions to improve clinical outcomes. We aimed to find the proportion of patients who tolerated LiDCO CNAP for 12 h postoperatively, to unmask episodes of hypotension detected by continuous monitoring and to characterise the haemodynamic profile at the time of hypotension. In this feasibility study, patients undergoing major elective surgery were continuously postoperatively monitored using CNAP. Haemodynamic data gathered from CNAP, including nSVRI (nominal systemic vascular resistance index), nSVI (nominal stroke volume index), SVV (stroke volume variation) and blood pressure, were analysed using Microsoft Excel and GraphPad Prism 8. 104 patients (age (mean ± sd): 68 ± 14, male (56%)) had CNAP sited postoperatively. 39% tolerated the CNAP device for at least 12 h. Within the 104 patients a mean of 81.2 min of hypotension detected by CNAP was not detected by usual care. The proportion of low/normal/high nSVI was 71%, 27% and 2%, nSVRI was 43%, 17% and 40%, respectively. CNAP monitoring was not tolerated for 12 h in the majority of patients. There were many episodes of hypotension unmasked through continuous monitoring. Based on the advanced haemodynamic data provided it is possible that the underlying cause of a third of postoperative hypotensive episodes is vasodilation rather than hypovolaemia.Trial registry number: NCT04010058 (ClinicalTrials.gov) Date of registration: 08/07/2019.

Low cardiac output measured by bioreactance and adverse outcome in preterm infants with birth weight less than 1250 g

BackgroundRecently a new continuous non-invasive cardiac output measurement, bioreactance, has become available. Bioreactance measurement of cardiac output has been shown to correlate with left ventricular output detected by echocardiography in healthy term and preterm neonates. AimsOur aim was to correlate cardiac output measurements by bioreactance in the first 48 h of life with adverse outcomes attributable to hypoperfusion (peri/intraventricular haemorrhage (PIVH) and/or necrotising enterocolitis (NEC)) in the cohort of extremely preterm infants. Study designA prospective observational cohort study. SubjectsPreterm infants with birth weight less than 1250 g. Outcome measuresCardiac output was measured between six and 48 h of age by bioreactance. Our primary outcome was a difference in cardiac output between infants with an adverse outcome attributable to hypoperfusion (Group 1), and infants without the predefined adverse outcome (Group 2). ResultsThere were 39 infants enrolled in the study. There were six infants in Group 1. These infants had a significantly lower minimal cardiac output measurement compared to Group 2 (mean 36.7 ml/kg/min vs 64.5 ml/kg/min, p = .0006). The mean cardiac output in Group 1 was significantly lower on day one of life, followed by a significant increase in cardiac output on day two of life compared to Group 2. ConclusionsInfants with birth weight less than 1250 g and PIVH and/or NEC had significantly lower cardiac output compared to infants without these complications on day one of life. This low cardiac output was then followed by a significant increase on day two of life.

Are Noninvasive Continuous Cardiac Output Monitoring Interchangeable with Esophageal Doppler?

Objective: To compare the trending ability, accuracy, and precision of non-invasive stroke volume (SV) measurement based on a bioreactance technique and measurement of the pulse wave transit time (PWTT) versus the esophageal Doppler monitoring (EDM). Materials and Methods: Two hundred twenty-seven paired measurements from 10 patients who underwent abdominal surgery under general anesthesia were included for SV measurements. Pearson’s correlation coefficient was calculated, and Bland-Altman analysis was performed to evaluate the agreement between EDM and bioreactance (EDM-bioreactance) and between EDM and PWTT (EDM-PWTT). Results: EDM-bioreactance had a correlation coefficient of 0.75 (95% confidence interval [CI] 0.62 to 0.78; p&lt;0.001), bias of 0.28 ml (limits of agreement –30.92 to 31.38 ml), and percentage error of 46.82%. EDM-PWTT had a correlation coefficient of 0.48 (95% CI 0.44 to 0.72; p&lt;0.001), bias of –0.18 ml (limits of agreement –40.28 to 39.92 ml), and percentage error of 60.17%. A subgroup analysis of data from patients who underwent crystalloid loading was performed to detect the trending ability. The four-quadrant plot analysis between EDM-bioreactance and EDM-PWTT demonstrated concordance rates of 70.00% and 73.68%, respectively. Conclusion: SV measurement based on bioreactance technique and measurement of PWTT are not interchangeable with EDM. Trial registration: Thai Clinical Trials Registry, TCTR 20181217003 Keywords: Stroke volume, Cardiac output, Doppler, Perioperative care, Pulse, Time

The Effect of Surgical Patient Positions on Plet Variability Index, Perfusion Index and Noninvasive Continuous Cardiac Output Measurement Method in Voluntary Breathing Volunteers

Amaç: Cerrahi prosedür için verilen farklı pozisyonlar doku perfüzyonunda ve kardiyak outputta değişikliklere neden olabilir. Bu çalışmada spontan solunuma sahip katılımcılarda plet değişkenlik indeksinin (PVI), perfüzyon indeks (PI) ve noninvaziv sürekli kardiyak output ölçüm yöntemi (EscCO) nin farklı cerrahi pozisyonlardaki değişimlerini araştırmayı amaçladık.Materyal ve Metod: 20 katılımcıdan oluşan bir sağlıklı birey grubu prospektif gözlemsel çalışmaya dahil edildi. Sırasıyla Supin, 30 derece baş yukarı, 45 derece baş yukarı, 20 derece Trendelenburg, 20 derece ters-Trendelenburg, ve pron pozisyonları uygulandı. Her pozisyon arası 10 ar dk olacak şekilde süre tutuldu. Her pozisyon değişikliğinden önce gönüllüler sırtüstü pozisyona alındı ve beş dakika dinlendikten sonra yeni pozisyon verildi. Pozisyon değişiminden sonraki 5. dakika PI, PVI, EscCO, SpO2 değerleri kayıt altına alındı.Bulgular: Katılımcıların farklı pozisyondayken ölçülen PI, PVI ile EscCO değerlerinde istatistiksel olarak anlamlı bir fark bulunamadı.Sonuç: Bu çalışma, PI, PVI ile EscCO nun tüm cerrahi pozisyonlarda herhangi bir değişikliğe uğramadığını ve her üç parametrenin de spontan solunumuna sahip genç sağlıklı bireylerde pozisyondan etkilenmediği ortaya koymuştur.

Non-invasive Continuous Cardiac Output Monitoring in Preterm Infants Study

Non-invasive Continuous Cardiac Output Monitoring in Preterm Infants Study

Progress in noninvasive assessment of fluid responsiveness

Fluid infusion is one of the most common therapeutic measures in clinical practice. With the development of medical technology, the assessment of fluid responsiveness before fluid infusion has become simpler and less invasive. The assessment of fluid responsiveness is based on three aspects: cardiopulmonary interaction, volume-loading test and endogenous volume-loading test. This article reviews the progress in the assessment of fluid responsiveness with the application of ultrasound and noninvasive continuous cardiac output monitoring, and the prospect of future improvement. Key words: Noninvasive; Ultrasound; Continuous cardiac output monitoring; Fluid responsiveness

The effect of haemodynamic and peripheral vascular variability on cardiac output monitoring: thermodilution and non-invasive pulse contour cardiac output during cardiothoracic surgery.

While haemodynamic variability interferes with the assumption of constant flow underlying thermodilution cardiac output calculation, variability in (peripheral) arterial vascular physiology may affect pulse contour cardiac output methods. We compared non-invasive finger arterial pressure-derived continuous cardiac output measurements (Nexfin® ) with cardiac output measured using thermodilution during cardiothoracic surgery and determined the impact of cardiovascular variability on either method. We compared cardiac output derived from non-invasive finger arterial pressure with cardiac output measured by thermodilution at four grades (A-D) of cardiovascular variability. We defined Grade A data as heart rate and mean arterial pressure variability < 5% and the absence of arrhythmias (implying stable flow) and Physiocal® interval (as measure of variability in finger arterial physiology) > 30 beats. Grade B included all levels of heart rate/mean arterial pressure variability and arrhythmias (Physiocal < 30 excluded). Grade C included all Physiocal intervals (heart rate/mean arterial pressure variability > 5% and arrhythmias excluded). Grade D included all data. Comparison results were quantified as percentage errors. We analysed measurements in 27 patients undergoing coronary artery bypass surgery. Before extracorporeal circulation, the percentage error was 23% (n = 14 patients) in grade A, 28% (n = 20) in grade B, 32% (n = 22) in grade C and 37% (n = 26) in grade D, with a significant increase in variance (p = 0.035). Bias did not differ between grades. After extracorporeal circulation (n = 27), percentage errors became larger, but were not different between grades. Variability during cardiothoracic surgery affected the comparison between thermodilution and non-invasive finger arterial pressure-derived cardiac output. When the main sources of variability were included, percentage errors were large. Future cardiac output methodology comparison studies should report haemodynamic variability.

Comparison of dexmedetomidine versus propofol on hemodynamics in surgical critically ill patients

BackgroundSedation with dexmedetomidine and propofol may cause hypotension or bradycardia. This study aimed to compare the effects of dexmedetomidine and propofol on hemodynamics and clinical outcomes in surgical intensive care unit (ICU) patients after major abdominal surgery. Materials and methodsEnrolled patients were randomly allocated to the dexmedetomidine or propofol group. Cardiac index was measured using a continuous noninvasive cardiac output monitor on the basis of chest bioreactance. Heart rate, blood pressure, opioid requirement, urine output, delirium incidence, ICU length of stay, and total hospital length of stay were compared between the two groups. The incidences of bradycardia, hypotension, and severe low cardiac index were compared. ResultsWe enrolled 60 patients. Heart rate and mean arterial pressure were significantly lower in the dexmedetomidine group than in the propofol group. Cardiac index did not differ significantly between the two groups (dexmedetomidine group 3.1 L/min/m2, [95% confidence interval {95% CI} 2.8-3.3] versus propofol group 3.2 L/min/m2 [95% CI 2.9-3.5], P = 0.578). The incidences of bradycardia, hypotension, and severe low cardiac index did not differ significantly between the two groups. ConclusionsCardiac index did not differ significantly between the dexmedetomidine and propofol groups in surgical ICU patients after major abdominal surgery.

Responsiveness of Noninvasive Continuous Cardiac Output Monitoring During the Valsalva Maneuver.

To describe the baseline hemodynamic variables and response time of hemodynamic changes associated with the Valsalva maneuver using noninvasive continuous cardiac output monitoring (Nexfin). Hemodynamic monitoring provides an integral component of advanced clinical care and the ability to monitor response to treatment interventions. The emergence of noninvasive hemodynamic monitoring provides clinicians with an opportunity to monitor and assess patients rapidly with ease of implementation. However, the responsiveness of this method in tracking dynamic changes that occur has not been fully elucidated. A prospective observational study was conducted involving 44 healthy volunteers (age = 38 ±12 years). Participants performed a Valsalva maneuvers to illicit dynamic changes in blood pressure, cardiac output, cardiac index, systemic vascular resistance index (SVRI), and stroke volume. Changes in these hemodynamic parameters were monitored while performing repeated standardized Valsalva maneuvers. Baseline hemodynamic values were obtained in all 44 participants, and showed an interaction with age, accompanying a significant decline in cardiac index (r = -.66, p < .05) and stroke volume (r = -.68,p < .05), and an increase in SVRI (r = .67, p < .05) with increasing age. The Valsalva maneuver, performed in 20 participants, resulted in a change of 10% from baseline blood pressure and cardiac index, which was detected within 4.53 s (SD = 4.36) and 3.31 s (SD = 2.21), respectively. Noninvasive continuous cardiac monitoring demonstrated the ability to rapidly detect logical and predictable hemodynamic changes. These observations suggest that such Nexfin technology may have useful clinical applications.