Validation of an Ultrasound Cardiac Output Monitor as a Bedside Tool for Pediatric Patients

Inferior vena cava-aortic ratio measurement as a promising modality in assessing intravascular volume in children with sepsis

BACKGROUND

Hemodynamic monitoring is crucial for the comprehensive management of children with sepsis, particularly those involving the kidneys. Sepsis-associated acute kidney injury (S-AKI) is closely linked to poor outcomes. Recently, ultrasonography modalities have been widely accepted as a non-invasive, rapid, and reliable tool for assessing volume status. We conducted research to determine intravascular volume based on ultrasound examination in S-AKI patients.

METHODS

A prospective cohort study was conducted between December 2023 and March 2024 in the Pediatric Intensive Care Unit (PICU) at Hasan Sadikin General Hospital. We divided the patients into two groups: those with sepsis without AKI and those with S-AKI. The intravascular volume was measured by the IVC/Ao (inferior vena cava/abdominal aorta) ratio using two-dimensional ultrasonography and USCOM before and 24 h after fluid treatment. The results were analyzed using SPSS 25, with a significance level of p < 0.05.

RESULTS

A total of 36 pediatric patients (aged 1 month-18 years) with sepsis were included. The IVC/Ao ratio before and after the fluid intervention demonstrated significant differences between the two groups (p < 0.001). USCOM Cardiac Index (CI) before and after the intervention also showed significant differences between the two groups (p < 0.001). Patients with S-AKI exhibited a poor hemodynamic response in the IVC/Ao ratio two-dimensional ultrasonography and USCOM examination.

CONCLUSIONS

IVC/Ao ratio measurement is as accurate as USCOM and can be used as a simple and cost-effective alternative for hemodynamic monitoring.

Comparative efficacy of finger versus forehead Plethysmographic Variability Index monitoring in pediatric surgical patients

INTRODUCTION

The Plethysmographic Variability Index can be measured by both finger and forehead probes. Vasoconstriction may jeopardize the reliability of finger PVI measurements in pediatric patients undergoing surgery. However, forehead vasculature exhibits more marked resistance to alterations in the vasomotor tonus.

OBJECTIVE

Our aim was to compare the Plethysmographic Variability Index measured via finger or forehead probes in mechanically ventilated pediatric surgery patients in terms of their ability to predict fluid responsiveness as well as to determine the best cut-off values for these two measurements.

MATERIALS AND METHODS

A total of 50 pediatric patients undergoing minor elective surgery were included after provision of parental consent and ethics committee approval. Perfusion index measured at the finger or forehead and Plethysmographic Variability Index monitoring comprised the primary assessments. Hemodynamic parameters monitored included perfusion index, Plethysmographic Variability Index, and cardiac output. A ≥ 15% increase in cardiac output following passive leg raise maneuver was considered to show fluid responsiveness. Two groups were defined based on fluid responsiveness: Group R (responsive) and Group NR (non-responsive). Student's t-test, Mann-Whitney U test, DeLong test, and ROC were used for statistical analysis.

RESULTS

The area under curve for finger and forehead Plethysmographic Variability Index prior to passive leg raise maneuver were 0.699 (p = .011) and 0.847 (p < .001), respectively. The sensitivity for finger and forehead measurements at a cut-off value of ≤14% was 92.9% and 96.4%, and 45.4% and 72.7%, respectively.

CONCLUSION

Although forehead and finger Plethysmographic Variability Index monitoring were similarly sensitive in predicting fluid responsiveness in pediatric surgical patients, the former method provided higher specificity. The best cut-off value for PVI measurements with forehead and finger probes was found to be 14%.

Perioperative fluid management in children: an updated review

Background: Perioperative fluid management in children has been a major topic for debate. Objectives: Our aim is to review the current evidence on perioperative fluid management in children including: type of fluid, administration rates, preoperative fluid intake and monitoring techniques. Design: Narrative review. Method: Following the PRISMA-S guidelines we performed a search (2010-March 2022) in databases Medline (through PubMed) and Cochrane Library. 4297 citations were found and screened by two independent researchers. After screening, 64 articles were withheld for our review. Results: The perioperative administration of isotonic fluids is safer than hypotonic solutions, concerning the development of hyponatremia. A balanced isotonic solution with 1-2,5% glucose should be used as perioperative maintenance IV fluid in children (1 month to 18 years). Colloids can be used in children when inadequate effect in volume correction is achieved with crystalloids. The preferred synthetic colloid for children is a third generation HES in a balanced solution. To date, most clinicians use the “4-2-1 rule” for calculating fluid rate. This may not be the optimal fluid rate, as little research has been done. Preoperative fasting for clear fluids should be limited to 1 hour, children should even be encouraged to drink up until 1 hour before induction. Respiratory variation of aortic blood flow peak velocity (ΔVpeak) with echocardiography is currently the most reliable technique for evaluating fluid responsiveness in children.

Measurement of Cardiac Output Using an Ultrasonic Cardiac Output Monitor (USCOM) in Patients with Single-Ventricle Physiology

We evaluate the validity of cardiac index (CI) measurements utilizing the Ultrasonic Cardiac Output Monitor (USCOM), a non-invasive Doppler ultrasound device, by comparing measurements to cardiac catheterization-derived CI measurements in patients with single-ventricle physiology. USCOM measurements were repeated three times for each patient at the beginning of a cardiac catheterization procedure for twenty-six patients undergoing elective pre-Glenn or pre-Fontan catheterization. CI was measured by USCOM and was calculated from cardiac catheterization data using Fick's method. Bland-Altman analysis for CI showed bias of 0.95 L/min/m² with the 95% limits of agreement of - 1.85 and 3.75. Pearson's correlation coefficient was 0.89 (p < 0.001) indicating a strong positive relationship between USCOM and cardiac catheterization CI measurements. When excluding two patients with significant dilation of the neo-aortic valve (z-score >  + 5), the bias improved to 0.66 L/min/m² with the 95% limits of agreement of - 1.38 and 2.70. Percent error of limits of agreement was 34%. There was excellent intra-operator reproducibility of USCOM CI measurements with an intra-class coefficient of 0.96. We demonstrate the use of USCOM to measure CI in patients with single-ventricle physiology for the first time, showing acceptable agreement of the CI measurements between USCOM and cardiac catheterization with a high intra-operator reproducibility.

Comparisons of Continuous-wave Doppler Ultrasound Monitor and Echocardiography in Cardiac Postoperative Pediatric Patients

RATIONAL AND OBJECTIVES

Non-invasive cardiac output (CO) measurements are essential during the immediate post-operative course of young, congenital heart repaired patients. The use of the Ultrasonic Cardiac Output Monitor (USCOM) in pediatric intensive care units (PICU) is increasing. The literature on accuracy of USCOM in young, critically ill, mechanically ventilated, hemodynamically supported patients is scarce. We aimed to assess agreement between the USCOM device and echocardiography for measurements of CO in this population.

MATERIALS (PATIENTS) AND METHODS

A prospective observational study in a pediatric cardiac intensive care unit (PCICU). Paired CO measurements were taken in young, mechanically ventilated, immediate post-operative patients with exclusion of unrepaired or residual intra-cardiac shunt, using USCOM and echocardiography, by two separate senior performers. Agreement between echocardiography and USCOM was assessed by percentage error and Bland-Altman analysis.

RESULTS

One hundred and thirteen comparison scans were performed on 61 patients: mean age 94 ± 111 d, weight 4.7 ± 2.1 kg, vaso-inotropic score 15.3 ± 11, and STAT score 3-4 (46%). Mean USCOM cardiac index (CI) percent difference was -9.6% (45.6) and velocity-time-integral (VTI) 8.9% (34.7). Bland-Altman analyzes demonstrated poor agreement comparing USCOM to echocardiography with regard to CI, stroke volume (SV), VTI and aortic diameter (AO) measurements.

CONCLUSION

Our study shows that USCOM underestimates CI in comparison with echocardiography; therefore USCOM should be used with great caution as an absolute estimate or surrogate of CI in neonates and infants in the immediate post-operative, congenital heart surgery period.

Serum NT-Pro-BNP versus Noninvasive Bedside Inotropic Index in Paediatric Shock: A Contest of Myocardial Performance in Response to Fluid Loading

Background

Mild elevation of serum amino-terminal pro-B-type natriuretic peptide (NT-pro-BNP) is associated with myocardial dysfunction. A significantly lower Smith-Madigan inotropic index (SMII) has been shown to accurately represent cardiac contractility among heart failure subjects. We aim to monitor the effect of fluid resuscitation on cardiac function among paediatric patients by measuring serum NT-pro-BNP and SMII.

Methods

This is an observational study on 70 paediatric shock patients. NT-pro-BNP and noninvasive bedside haemodynamic monitoring were done by using an ultrasonic cardiac output monitor (USCOM, USCOM, Sydney, Australia). The presence of cardiac diseases was excluded. SMII was obtained from the USCOM. An increase in the stroke volume index (SVI) of ≥15% indicates fluid responders. Measurements were taken before and after fluid loading.

Results

Preloading NT-pro-BNP and SMII category were significantly different between the fluid responsiveness group, p=0.001 and p=0.004, respectively. Higher median NT-pro-BNP (preloading NT-pro-BNP of 1175.00 (254.50-9965.00) ng/mL vs. 196.00 (65.00-509.00) ng/mL, p=0.002) was associated with fluid nonresponders (subjects >12 months old). Preloading NT-pro-BNP <242.5 ng/mL was associated with fluid responders (AUC: 0.768 (0.615-0.921), p=0.003), 82.1% sensitivity, and 68.7% specificity for subjects >12 years old. Delta NT-pro-BNP in fluid responders (15.00 (-16.00-950.00) ng/mL) did not differ from fluid nonresponders (505.00 (-797.00-1600.00) ng/mL), p=0.456. Postloading SMII >1.25 W·m^-2 was associated with fluid responders (AUC: 0.683 (0.553-0.813), p = 0.011), 61.9% sensitivity, and 66.7% specificity, but not preloading SMII. Fluid responders had a higher mean postloading SMII compared to nonresponders (1.36 ± 0.38 vs. 1.10 ± 0.34, p=0.006).

Conclusion

Higher NT-pro-BNP and lower SMII in the absence of cardiac diseases were associated with poor response to fluid loading. The SMII is affected by low preload conditions.

Hemodynamic monitoring and management of pediatric septic shock

Sepsis remains a major cause of morbidity and mortality among children worldwide. Furthermore, refractory septic shock and multiple organ dysfunction syndrome are the most critical groups which account for a high mortality rate in pediatric sepsis, and their clinical course often deteriorates rapidly. Resuscitation based on hemodynamics can provide objective values for identifying the severity of sepsis and monitoring the treatment response. Hemodynamics in sepsis can be divided into two groups: basic and advanced hemodynamic parameters. Previous therapeutic guidance of early-goal directed therapy (EGDT), which resuscitated based on the basic hemodynamics (central venous pressure and central venous oxygen saturation (ScvO2)) has lost its advantage compared with “usual care”. Optimization of advanced hemodynamics, such as cardiac output and systemic vascular resistance, has now been endorsed as better therapeutic guidance for sepsis. Despite this, there are still some important hemodynamics associated with prognosis. In this article, we summarize the common techniques for hemodynamic monitoring, list important hemodynamic parameters related to outcomes, and update evidence-based therapeutic recommendations for optimizing resuscitation in pediatric septic shock.

Ultrasonic cardiac output monitor provides effective non-invasive bedside measurements of neonatal cardiac output

This study determined the accuracy and validity for the haemodynamic parameters of haemodynamically stable neonates after postnatal circulatory adaptation using the ultrasonic cardiac output monitor (USCOM) in comparison with echocardiography. We conducted a prospective, observational study of neonates born at 23-41 weeks of gestation. They all underwent both echocardiography and USCOM assessments for comparison purposes. The 127 neonates were examined at the median of postmenstrual age of 35 weeks and there was a very high correlation between the cardiac output measurements provided by both methods. The mean difference in cardiac output was - 12 ± 25 ml/kg/min, with percentage error of 8.3 ± 6.9%. A larger bias was observed in cases with higher left ventricular output. Bland-Altman analysis confirmed no significant bias, with acceptable limits of agreement between these two methods. There was a very good correlation between the USCOM and echocardiographic methods when we used them to measure cardiac output in neonates.

Ultrasound Cardiac Output Monitor (USCOM™) Measurements Prove Unreliable Compared to Cardiac Magnetic Resonance Imaging in Adolescents with Cardiac Disease

The purpose of this stuy is to prospectively assess the reliability of the ultrasound cardiac output monitor (USCOM™) for measuring stroke volume index and predicting left ventricular outflow tract diameter in adolescents with heart disease. Sixty consecutive adolescents with heart disease attending a tertiary medical center underwent USCOM™ assessment immediately after cardiac magnetic resonance imaging. USCOM™ measured stroke volume index and predicted left ventricular outflow tract diameter were compared to cardiac magnetic resonance imaging-derived values using Bland-Altman analysis. Ten patients with an abnormal left ventricular outflow tract were excluded from the analysis. An adequate USCOM™ signal was obtained in 49/50 patients. Mean stroke volume index was 46.1 ml/m² by the USCOM™ (range 22-66.9 ml/m²) and 42.9 ml/m² by cardiac magnetic resonance imaging (range 24.7-59.9 ml/m²). The bias (mean difference) was 3.2 ml/m²; precision (± 2SD of differences), 17 ml/m²; and mean percentage error, 38%. The mean (± 2SD) left ventricular outflow tract diameter was 0.445 ± 0.536 cm smaller by the USCOM™ algorithm prediction than by cardiac magnetic resonance imaging. Attempted adjustment of USCOM™ stroke volume index using cardiac magnetic resonance imaging left ventricular outflow tract diameter failed to improve agreement between the two modalities (bias 28.4 ml/m², precision 44.1 ml/m², percentage error 77.3%). Our study raises concerns regarding the reliability of USCOM™ for stroke volume index measurement in adolescents with cardiac disease, which did not improve even after adjusting for its inaccurate left ventricular outflow tract diameter prediction.

Stable Automatic Envelope Estimation for Noisy Doppler Ultrasound

Doppler ultrasound technology is widespread in clinical applications and is principally used for blood flow measurements in the heart, arteries, and veins. A commonly extracted parameter is the maximum velocity envelope. However, current methods of extracting it cannot produce stable envelopes in high noise conditions. This can limit clinical and research applications using the technology. In this article, a new method of automatic envelope estimation is presented. The method can handle challenging signals with high levels of noise and variable envelope shapes. Envelopes are extracted from a Doppler spectrogram image generated directly from the Doppler audio signal, making it less device-dependent than existing image-processing methods. The method's performance is assessed using simulated pulsatile flow, a flow phantom, and in vivo ascending aortic flow measurements and is compared with three state-of-the-art methods. The proposed method is the most accurate in noisy conditions, achieving, on average, for phantom data with signal-to-noise ratios (SNRs) below 10 dB, bias and standard deviation of 0.7% and 3.3% lower than the next-best performing method. In addition, a new method for beat segmentation is proposed. When combined, the two proposed methods exhibited the best performance using in vivo data, producing the least number of incorrectly segmented beats and 8.2% more correctly segmented beats than the next best performing method. The ability of the proposed methods to reliably extract timing indices for cardiac cycles across a range of signal quality is of particular significance for research and monitoring applications.

Electrocardiometry Fluid Responsiveness in Pediatric Septic Shock

Hemodynamic monitoring and categorization of patients based on fluid responsiveness is the key to decisions prompting the use of fluids and vasoactive agents in septic shock. Distinguishing patients who are going to benefit from fluids from those who will not is of paramount importance as large amounts of fluids used conventionally based on surviving sepsis guidelines may be detrimental. Noninvasive monitoring techniques for the assessment of various cardiovascular parameters are increasingly accepted as the current medical practice. Electrical cardiometry (EC) is one such method for the determination of stroke volume, cardiac output (CO), and other hemodynamic parameters and is based on changes in electrical conductivity within the thorax. It has been validated against gold standard methods such as thermodilution [Malik V, Subramanian A, Chauhan S, et al. World J 2014;4(7):101-108] and is being used more often as a point-of-care noninvasive technique for hemodynamic monitoring. EC is Food and Drug Administration approved and validated for use in neonates, children, and adults. A meta-analysis in 2016, including 20 studies and 624 patients comparing the accuracy of CO measurement by using EC with other noninvasive technologies, demonstrated that EC was the device that offered the most correct measurements. The article in the current issue of IJCCM by Rao et al. (2020) has extended the use of EC to categorize pediatric patients with septic shock into vasodilated and vasoconstricted states based on systemic vascular resistance and correlate the categorization clinically. The authors also studied the changes in hemodynamic parameters after an isotonic fluid bolus of 20 mL/kg was administered. This is a pilot prospective observational study of 30 patients, which has given an insight into physiological rearrangements following fluid administration in patients with septic shock. How to cite this article: Gupta D, Dhingra. Electrocardiometry Fluid Responsiveness in Pediatric Septic Shock. Indian J Crit Care Med 2021;25(2):123-125.

Performance evaluation of a portable bioimpedance cardiac output monitor for measuring hemodynamic changes in athletes during a head-up tilt test

The use of impedance cardiography to monitor physiological changes in sports is rarely reported. Using head-up tilt test, we evaluated a portable noninvasive impedance cardiography device (PhysioFlow) by comparing it with a reference Doppler monitor (USCOM). Accuracy in tracking hemodynamic changes deteriorated with higher tilt, implying a gravitational influence on its performance. Stroke volume measurements were overestimated, but the changes were underestimated. Despite its convenient physical features, the suitability of PhysioFlow for sports use is questionable.

Cardiac output measurements via echocardiography versus thermodilution: A systematic review and meta-analysis

Echocardiography, as a noninvasive hemodynamic evaluation technique, is frequently used in critically ill patients. Different opinions exist regarding whether it can be interchanged with traditional invasive means, such as the pulmonary artery catheter thermodilution (TD) technique. This systematic review aimed to analyze the consistency and interchangeability of cardiac output measurements by ultrasound (US) and TD. Five electronic databases were searched for studies including clinical trials conducted up to June 2019 in which patients’ cardiac output was measured by ultrasound techniques (echocardiography) and TD. The methodological quality of the included studies was evaluated by two independent reviewers who used the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), which was tailored according to our systematic review in Review Manager 5.3. A total of 68 studies with 1996 patients were identified as eligible. Meta-analysis and subgroup analysis were used to compare the cardiac output (CO) measured using the different types of echocardiography and different sites of Doppler use with TD. No significant differences were found between US and TD (random effects model: mean difference [MD], -0.14; 95% confidence interval, -0.30 to 0.02; P = 0.08). No significant differences were observed in the subgroup analyses using different types of echocardiography and different sites except for ascending aorta (AA) (random effects model: mean difference [MD], -0.37; 95% confidence interval, -0.74 to -0.01; P = 0.05) of Doppler use. The median of bias and limits of agreement were -0.12 and ±0.94 L/min, respectively; the median of correlation coefficient was 0.827 (range, 0.140–0.998). Although the difference in CO between echocardiography by different types or sites and TD was not entirely consistent, the overall effect of meta-analysis showed that no significant differences were observed between US and TD. The techniques may be interchangeable under certain conditions.

Minimal Change in Cardiac Index With Increasing PEEP in Pediatric Acute Respiratory Distress Syndrome

Objective: To determine if increasing positive end expiratory pressure (PEEP) leads to a change in cardiac index in children with Pediatric Acute Respiratory Distress Syndrome ranging from mild to severe. Design: Prospective interventional study. Setting: Multidisciplinary Pediatric Intensive Care Unit in a University teaching hospital. Patients: Fifteen intubated children (5 females, 10 males) with a median age of 72 months (IQR 11, 132) and a median weight of 19.3 kg (IQR 7.5, 53.6) with a severity of Pediatric Acute Respiratory Distress Syndrome that ranged from mild to severe with a median lung injury score of 2.3 (IQR 2.0, 2.7). Measurements: Cardiac index (CI) and stroke volume (SV) were measured on baseline ventilator settings and subsequently with a PEEP 4 cmH₂O higher than baseline. Change in CI and SV from baseline values was evaluated using Wilcoxon signed rank test. Results: A total of 19 paired measurements obtained. The median baseline PEEP was 8 cmH₂O (IQR 8, 10) Range 6-14 cmH₂O. There was no significant change in cardiac index or stroke volume with change in PEEP. Baseline median CI 4.4 L/min/m² (IQR 3.4, 4.8) and PEEP 4 higher median CI of 4.3 L/min/m² (IQR 3.6, 4.8), p = 0.65. Baseline median SV 26 ml (IQR 13, 44) and at PEEP 4 higher median SV 34 ml (IQR 12, 44) p = 0.63. Conclusion: There is no significant change in cardiac index or stroke volume with increasing PEEP by 4 cmH₂O in a population of children with mild to severe PARDS. Clinical Trial Registration: The study is registered on Clinical trails.gov under the Identifier: NCT02354365.

Noninvasive hemodynamic monitoring of septic shock in children

Septic shock in children is associated with high mortality and morbidity. Its management is time-sensitive and must be aggressive and target oriented. The use of clinical assessment alone to differentiate between cold and warm shock and to select the appropriate inotropic and vasoactive medications is fraught with errors. Semi-quantitative and quantitative assessment of the preload, contractility and afterload using non-invasive tools has been suggested, in conjunction with clinical and laboratory assessment, to direct shock management and select between vasopressors, vasodilators and inotropes or a combination of these drugs. This review aims to describe non-invasive tools to assess the hemodynamic status in septic shock including echocardiography, trans-thoracic/trans-esophageal Doppler and electrical cardiometry. As septic shock is a dynamic condition that changes markedly overtime, frequent or continuous measurement of the cardiac output (CO), systemic vascular resistance (SVR) and other hemodynamic parameters using the above-mentioned tools is essential to personalize the treatment and adapt it over time. The different combinations of blood pressure, CO and SVR serve as a pathophysiological framework to manage fluid therapy and titrate inotropic and vasoactive drugs. Near infrared spectroscopy is introduced as a non-invasive method to measure end organ perfusion and assess the response to treatment.

Comparison of three non-invasive hemodynamic monitoring methods in critically ill children

Introduction

Hemodynamic parameters measurements were widely conducted using pulmonary artery catheter (PAC) with thermodilution as a reference standard. Due to its technical difficulties in children, transthoracic echocardiography (TTE) has been widely employed instead. Nonetheless, TTE requires expertise and is time-consuming. Noninvasive cardiac output monitoring such as ultrasonic cardiac output monitor (USCOM) and electrical velocimetry (EV) can be performed rapidly with less expertise requirement. Presently, there are inconsistent evidences, variable precision, and reproducibility of EV, USCOM and TTE measurements. Our objective was to compare USCOM, EV and TTE in hemodynamic measurements in critically ill children.

Materials and methods

This was a single center, prospective observational study in critically ill children. Children with congenital heart diseases and unstable hemodynamics were excluded. Simultaneous measurements of hemodynamic parameters were conducted using USCOM, EV, and TTE. Inter-rater reliability was determined. Bland-Altman plots were used to analyse agreement of assessed parameters.

Results

Analysis was performed in 121 patients with mean age of 4.9 years old and 56.2% of male population. Interrater reliability showed acceptable agreement in all measured parameters (stroke volume (SV), cardiac output (CO), velocity time integral (VTI), inotropy (INO), flow time corrected (FTC), aortic valve diameter (AV), systemic vascular resistance (SVR), and stroke volume variation (SVV); (Cronbach’s alpha 0.76–0.98). Percentages of error in all parameters were acceptable by Bland-Altman analysis (9.2–28.8%) except SVR (30.8%) and SVV (257.1%).

Conclusion

Three noninvasive methods might be used interchangeably in pediatric critical care settings with stable hemodynamics. Interpretation of SVV and SVR measurements must be done with prudence.

New directions in point-of-care ultrasound at the crossroads of paediatric emergency and critical care

PURPOSE OF REVIEW

The diagnostic capability, efficiency and versatility of point-of-care ultrasound (POCUS) have enabled its use in paediatric emergency medicine (PEM) and paediatric critical care (PICU). This review highlights the current applications of POCUS for the critically ill child across PEM and PICU to identify areas of progress and standardized practice and to elucidate areas for future research.

RECENT FINDINGS

POCUS technology continues to evolve and advance bedside clinical care for critically ill children, with ongoing research extending its use for an array of clinical scenarios, including respiratory distress, trauma and dehydration. Rapidly evolving and upcoming applications include diagnosis of pneumonia and acute chest syndrome, identification of intra-abdominal injury via contrast-enhancement, guidance of resuscitation, monitoring of increased intracranial pressure and procedural guidance.

SUMMARY

POCUS is an effective and burgeoning method for both rapid diagnostics and guidance for interventions and procedures. It has clinical application for a variety of conditions that span PEM and PICU settings. Formal POCUS training is needed to standardize and expand use of this valuable technology by PICU and PEM providers alike.

Race predictors and hemodynamic alteration after an ultra-trail marathon race

OBJECTIVE

Unique rough-terrain ultra-trail running races have increased in popularity. Concerns regarding the suitability of the candidates make it difficult for organizers to manage safety regulations. The purpose of this study was to identify possible race predictors and assess hemodynamic change after long endurance races.

METHODS

We studied 228 runners who competed in a 66 km-trail running race. A questionnaire and noninvasive hemodynamic flow assessment including blood pressure, heart rate, stroke volume, stroke volume variation, systemic vascular resistance, cardiac index, and oxygen saturation were used to determine physiologic alterations and to identify finish predictors. One hundred and thirty volunteers completed the questionnaire, 126 participants had a prerace hemodynamic assessment, and 33 of these participants completed a postrace assessment after crossing the finish line. The participants were divided into a finisher group and a nonfinisher group.

RESULTS

The average age of all runners was 37 years (range of 24-56 years). Of the 228 runners, 163 (71.5%) were male. There were 189 (82.9%) finishers. Univariable analysis indicated that the finish predictors included male gender, longest distance ever run, faster running records, and lower diastolic pressure. Only a lower diastolic pressure was a significant predictor of race finishing (diastolic blood pressure 74-84 mmHg: adjusted odd ratio 3.81; 95% confidence interval [CI] =1.09-13.27 and diastolic blood pressure <74 mmHg: adjusted odd ratio 7.74; 95% CI =1.57-38.21) using the figure from the multivariable analysis. Among the finisher group, hemodynamic parameters showed statistically significant differences with lower systolic blood pressure (135.9±14.8 mmHg vs 119.7±11.3 mmHg; p<0.001), faster heart rate (72.6±10.7 bpm vs 96.4±10.4 bpm; p<0.001), lower stroke volume (43.2±13.6 mL vs 29.3±10.1 mL; p<0.001), higher stroke volume variation; median (interquartile range) (36% [25%-58%] vs 53% [33%-78%]; p<0.001), and lower oxygen saturation (97.4%±1.0% vs 96.4%±1.0%; p<0.001). Systemic vascular resistance and cardian index did not change significantly.

CONCLUSION

The only race finishing predictor from the multivariable analysis was lower diastolic pressure. Finishers seem to have a hypovolemic physiologic response and a lower level of oxygen saturation.

[Application of ultrasonic cardiac output monitor in evaluation of cardiac function in children with severe pneumonia]

OBJECTIVE

To study the clinical application of ultrasonic cardiac output monitor (USCOM) in evaluation of cardiac function in children with severe pneumonia.

METHODS

Twenty-nine children with severe pneumonia were enrolled in the observation group and forty-three children with common pneumonia were enrolled in the control group. The USCOM was used to measure the cardiac function indices in the two groups. The results were compared between the two groups. The changes in cardiac function indices after treatment were evaluated in the observation group.

ESULTS

The observation group had a significantly higher heart rate and significantly lower cardiac output, systolic volume, and aortic peak velocity than the control group (P<0.05). There were no significant differences in cardiac index or systemic vascular resistance between the two groups (P>0.05). In the observation group, the heart rate, cardiac output, systolic volume, aortic peak velocity, cardiac index, and systemic vascular resistance were significantly improved after treatment (P<0.05).

CONCLUSIONS

The USCOM is a fast, convenient, and accurate approach for dynamic measurement of cardiac function and overall circulation state in children with severe pneumonia. The USCOM can provide a basis for diagnosis, treatment, and evaluation of the disease, which is quite useful in clinical practice.