Crystalloids vs. colloids for fluid optimization in patients undergoing brain tumour surgery

BACKGROUND

This randomised, double-blinded, single-centre study prospectively investigated the impact of goal directed therapy and fluid optimization with crystalloids or colloids on perioperative complications in patients undergoing brain tumour surgery. Main aim of the study was to investigate the impact of fluid type on postoperative complications.

PATIENTS AND METHODS

80 patients were allocated into two equal groups to be optimised with either crystalloids (n = 40) or colloids (n = 40). Invasive hemodynamic monitoring was used to adjust and maintain mean arterial pressure and cerebral oxygenation within the baseline values (± 20%) and stroke volume variation (SVV) ≤ 10%. Postoperative complications from different organ systems were monitored during the first 15 days after surgery. Hospital stay was also recorded.

RESULTS

Crystalloid group received significantly more fluids (p = 0.003) and phenylephrine (p = 0.02) compared to colloid group. This did not have any significant impact on perioperative complications and hospital stay, since no differences between groups were observed.

CONCLUSIONS

Either crystalloids or colloids could be used for fluid optimization in brain tumour surgery. If protocolised perioperative haemodynamic management is used, the type of fluid does not have significant impact on the outcome.

Comparison of Bioimpedance Versus Pulse Contour Analysis for Intraoperative Cardiac Index Monitoring in Patients Undergoing Kidney Transplantation

Background

Cardiac index (CI; cardiac output indexed to body surface area) is routinely measured during kidney transplant surgery. Bioimpedance cardiometry is a transthoracic impedance as the non-invasive alternative for hemodynamic monitoring, using semi-invasive uncalibrated pulse wave or contour (UPC) analysis.

Objectives

We performed a cross-sectional observational study on 50 kidney transplant patients to compare the CI measurement agreement, concordance rate, and trending ability between bioimpedance and UPC analysis.

Methods

For each patient, CI was measured by bioimpedance analysis (ICON^TM) and UPC analysis (EV1000^TM) devices at three time points: after induction, during incision, and at reperfusion. The device measurement accuracy was assessed by the bias value, limit of agreement (LoA), and percentage error (PE) using Bland-Altman analyses. Trending ability was assessed by angular bias and polar concordance through four-quadrant and polar plot analyses.

Results

From each time point and pooled measurement, the correlation coefficients were 0.267, 0.327, 0.321, and 0.348. Bland-Altman analyses showed mean bias values of 1.18, 1.06, 1.48, and 1.30, LoA of -1.35 to 3.72, -1.39 to 3.51, -1.07 to 4.04, and -1.17 to 3.78, and PE of 82.21, 78.50, 68.74, and 74.58%, respectively. Polar plot analyses revealed angular bias values of -10.37º, -15.01º, -18.68º, and -12.62º, with radial LoA of 89.79º, 85.86º, 83.38º, and 87.82º, respectively. The four-quadrant plot concordance rates were 70.77, 67.35, 65.90, and 69.79%. These analyses showed poor agreement, weak concordance, and low trending ability of bioimpedance cardiometry to UPC analysis.

Conclusions

Bioimpedance and UPC analysis for CI measurements were not interchangeable in patients undergoing kidney transplant surgery. Cardiac index monitoring using bioimpedance cardiometry during kidney transplantation should be interpreted cautiously because it showed poor reliability due to low accuracy, precision, and trending ability for CI measurement.

Journal of clinical monitoring and computing end of year summary 2018: hemodynamic monitoring and management

Hemodynamic management is a mainstay of patient care in the operating room and intensive care unit (ICU). In order to optimize patient treatment, researchers investigate monitoring technologies, cardiovascular (patho-) physiology, and hemodynamic treatment strategies. The Journal of Clinical Monitoring and Computing (JCMC) is a well-established and recognized platform for publishing research in this field. In this review, we highlight recent advancements and summarize selected papers published in the JCMC in 2018 related to hemodynamic monitoring and management.

Electrical impedance tomography for non-invasive assessment of stroke volume variation in health and experimental lung injury

BACKGROUND

Functional imaging by thoracic electrical impedance tomography (EIT) is a non-invasive approach to continuously assess central stroke volume variation (SVV) for guiding fluid therapy. The early available data were from healthy lungs without injury-related changes in thoracic impedance as a potentially influencing factor. The aim of this study was to evaluate SVV measured by EIT (SVV_EIT) against SVV from pulse contour analysis (SVV_PC) in an experimental animal model of acute lung injury at different lung volumes.

METHODS

We conducted a randomized controlled trial in 30 anaesthetized domestic pigs. SVV_EIT was calculated automatically analysing heart-lung interactions in a set of pixels representing the aorta. Each initial analysis was performed automatically and unsupervised using predefined frequency domain algorithms that had not previously been used in the study population. After baseline measurements in normal lung conditions, lung injury was induced either by repeated broncho-alveolar lavage (n=15) or by intravenous administration of oleic acid (n=15) and SVV_EIT was remeasured.

RESULTS

The protocol was completed in 28 animals. A total of 123 pairs of SVV measurements were acquired. Correlation coefficients (r) between SVV_EIT and SVV_PC were 0.77 in healthy lungs, 0.84 after broncho-alveolar lavage, and 0.48 after lung injury from oleic acid.

CONCLUSIONS

EIT provides automated calculation of a dynamic preload index of fluid responsiveness (SVV_EIT) that is non-invasively derived from a central haemodynamic signal. However, alterations in thoracic impedance induced by lung injury influence this method.

Radial Artery Tonometry to Monitor Blood Pressure and Hemodynamics in Ambulatory Left Ventricular Assist Device Patients in Comparison With Doppler Ultrasound and Transthoracic Echocardiography: A Pilot Study

Noninvasive measurements of blood pressure (BP) and cardiac output (CO) are crucial in the follow-up of continuous-flow left ventricular assist device (CF-LVAD) patients. For our pilot study, we sought to compare BP measurements between a tonometry blood pressure pulse analyzer (BPPA) (DMP-Life, DAEYOMEDI Co., Ltd., Gyeonggi-do, South Korea) and Doppler ultrasound in CF-LVAD patients, as well as to compare the BPPA estimated CO to LVAD calculated blood flow and to the patient's intrinsic CO estimated with transthoracic echocardiography (TTE). Ambulatory CF-LVAD patients (6 HeartMate, 26 HeartMate II), were included. According to TTE findings, patients were then subdivided in two groups: patients with an opening aortic valve (OAV) [n = 21] and those with an intermittent opening aortic valve (IOAV) [n = 11]. We found a very good correlation of systolic BP (SBP) measurements between the two methods, BPPA and Doppler ultrasound (r = 0.87, P < 0.0001). Bland-Altman plots for SBP revealed a low bias of -4.6 mm Hg and SD of ±4.7 mm Hg. In CF-LVAD patients with IOAV, the BPPA-CO had a good correlation with the LVAD-flow (r = 0.78, P < 0.0001), but in OAV patients, there was no correlation. After adding the patient's intrinsic CO, estimated from TTE in patients with OAV to the LVAD-flow, we found a very good correlation between the BPPA-CO and LVAD-flow + TTE-CO (r = 0.81, P = 0.002). Our study demonstrated that compared with the standard clinical method, Doppler ultrasound, the BPPA measured BP noninvasively with good accuracy and precision of agreement. In addition, tonometry BPPA provided further valuable information regarding the CF-LVAD patient's intrinsic CO.

Reliability of Cardiac Output Measurements Using LiDCOrapid and Calibration by Transesophageal Echocardiography With the Continuous Pulmonary Artery Thermodilution Method in Patients Undergoing Aortic Valve Replacement for Aortic Stenosis

OBJECTIVE

This study investigated the accuracy of arterial waveform analysis estimations of cardiac output (CO_AW) and the efficacy of calibrations involving transesophageal echocardiography with continuous cardiac output values obtained using a pulmonary artery catheter.

DESIGN

Prospective cohort study.

SETTING

University hospital operating room.

PARTICIPANTS

Twelve patients undergoing aortic valve replacement for aortic stenosis.

INTERVENTIONS

A pulmonary artery catheter was placed in each patient, and continuous cardiac output was determined using thermodilution principles. LiDCOrapid and transesophageal echocardiography were used to measure CO_AW and to perform the calibration, respectively.

MEASUREMENTS AND MAIN RESULTS

Simultaneous recording of continuous cardiac output and CO_AW values were performed every 20 minutes, after inducing anesthesia. CO_AW was calibrated using transesophageal echocardiography (CO_AW-cal) before and after initiating cardiopulmonary bypass (CPB); the CO_AW and CO_AW-cal were recorded concurrently using a LiDCOrapid monitor. For the pre-CPB dataset (34 data pairs), the mean bias and percentage error were, respectively, 0.10 L/min and 34% for CO_AW versus continuous cardiac output and -0.098 L/min and 27% for CO_AW-cal versus continuous cardiac output. Similarly, for the post-CPB (45 data pairs), the mean bias and percentage error were, respectively, 0.75 L/min and 34% for CO_AW and 0.059 L/min and 26% for CO_AW-cal. A 4-quadrant plot demonstrated an acceptable pre-CPB concordance rate of 93.3% for CO_AW and 93.8% for CO_AW-cal.

CONCLUSION

CO_AW measurements, using LiDCOrapid, have acceptable trending ability pre-CPB. The determination of cardiac output variations, using transesophageal echocardiography, is useful for managing patients undergoing aortic valve replacement for aortic stenosis.

Continuous noninvasive arterial blood pressure monitoring using the vascular unloading technology during complex gastrointestinal endoscopy: a prospective observational study

The innovative vascular unloading technology (VUT) allows continuous noninvasive arterial blood pressure (AP) monitoring. We aimed to investigate whether the VUT enables AP changes to be detected earlier compared with intermittent AP monitoring in patients undergoing gastrointestinal endoscopy. In this prospective observational study, we recorded continuous AP measurements with the VUT (CNAP system; CNSystems Medizintechnik AG, Graz, Austria) and intermittent AP measurements with upper arm cuff oscillometry in 90 patients undergoing complex gastrointestinal endoscopy (Department of Interventional Endoscopy at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany). A "hypotensive phase" was defined as a time period of at least 30 s during which ≥ 50% of the VUT-AP values were in a predefined range of hypotension, i.e., AP value a) ≥ 10% below the last oscillometric value and b) ≤ 65 mmHg for mean AP or ≤ 90 mmHg for systolic AP. In the 5-min-interval between two oscillometric measurements, one or more hypotensive phases were detected in 26 patients (29%) for mean AP and in 27 patients (30%) for systolic AP. Hypotensive phases had a mean duration of 195 ± 99 s for mean AP and 197 ± 97 s for systolic AP with a mean procedure duration of 36 (± 21) min. Continuous noninvasive AP monitoring using the VUT enables hypotensive phases to be detected earlier compared with intermittent AP monitoring during complex gastrointestinal endoscopy. These hypotensive phases may be missed or only belatedly recognized with intermittent AP monitoring. Continuous noninvasive AP measurement facilitates detecting hemodynamic instability more rapidly and therefore may improve patient safety.

Non-invasive imaging modalities to study neurodegenerative diseases of aging brain

The aim of this article is to highlight current approaches for imaging elderly brain, indispensable for cognitive neuroscience research with emphasis on the basic physical principles of various non-invasive neuroimaging techniques. The first part of this article presents a quick overview of the primary non-invasive neuroimaging modalities used by cognitive neuroscientists such as transcranial magnetic stimulation (TMS), transcranial electrical stimulation (tES), electroencephalography (EEG), magnetoencephalography (MEG), single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance spectroscopic imaging (MRSI), Profusion imaging, functional magnetic resonance imaging (fMRI), near infrared spectroscopy (NIRS) and diffusion tensor imaging (DTI) along with tractography and connectomics. The second part provides a comprehensive overview of different multimodality imaging techniques for various cognitive neuroscience studies of aging brain.

Comparison between radial artery tonometry pulse analyzer and pulsed-Doppler echocardiography derived hemodynamic parameters in cardiac surgery patients: a pilot study

Background

Bedside non-invasive techniques, such as radial artery tonometry, to estimate hemodynamic parameters have gained increased relevance as an attractive alternative and efficient method to measure hemodynamics in outpatient departments. For our pilot study, we sought to compare cardiac output (CO), and stroke volume (SV) estimated from a radial artery tonometry blood pressure pulse analyzer (BPPA) (DMP-Life, DAEYOMEDI Co., Gyeonggi-do, South Korea) to pulsed-wave Doppler (PWD) echocardiography derived parameters.

Methods

From January 2015 to December 2016, all patients scheduled for coronary artery bypass (CABG) surgery at our department were screened. Exclusion criteria were, inter alia, moderate to severe aortic- or Mitral valve disease and peripheral arterial disease (PAD) > stage II. One hundred and seven patients were included (mean age 66.1 ± 9.9, 15 females, mean BMI 27.2 ± 4.1 kg/m²). All patients had pre-operative transthoracic echocardiography (TTE). We measured the hemodynamic parameters with the BPPA from the radial artery, randomly before or after TTE. For the comparison between the measurement methods we used the Bland-Altman test and Pearson correlation.

Results

Mean TTE-CO was 5.1 ± 0.96 L/min, and the mean BPPA-CO was 5.2 ± 0.85 L/min. The Bland-Altman analysis for CO revealed a bias of −0.13 L/min and SD of 0.90 L/min with upper and lower limits of agreement of −1.91 and +1.64 L/min. The correlation of CO measurements between DMP-life and TTE was poor (r = 0.501, p < 0.0001). The mean TTE-SV was 71.3 ± 16.2 mL and the mean BPPA-SV was 73.8 ± 19.2 mL. SV measurements correlated very well between the two methods (r = 0.900, p < 0.0001). The Bland-Altman analysis for SV revealed a bias of −2.54 mL and SD of ±8.42 mL and upper and lower limits of agreement of −19.05 and +13.96 mL, respectively.

Conclusion

Our study shows for the first time that the DMP-life tonometry device measures SV and CO with reasonable accuracy and precision of agreement compared with TTE in preoperative cardiothoracic surgery patients. Tonometry BPPA are relatively quick and simple measuring devices, which facilitate the collection of cardiac and hemodynamic information. Further studies with a larger number of patients and with repeated measurements are in progress to test the reliability and repeatability of DMP-Life system.

Accuracy, Precision, and Trending of 4 Pulse Wave Analysis Techniques in the Postoperative Period

OBJECTIVE

The aim of this study was to analyze the accuracy, precision, and trending ability of the following 4 pulse wave analysis devices to measure continuous cardiac output: PiCCO₂ ([PCCO]; Pulsion Medical System, Munich, Germany); LiDCO_Rapid ([LCCO]; LiDCO Ltd, London, UK); FloTrac/Vigileo ([FCCO]; Edwards Lifesciences, Irvine, CA); and Nexfin ([NCCO]; BMEYE, Amsterdam, The Netherlands).

DESIGN

Prospective, observational clinical study.

SETTING

Intensive care unit of a single-center, teaching hospital.

PARTICIPANTS

The study comprised 22 adult patients after elective coronary artery bypass surgery.

INTERVENTIONS

Three measurement cycles were performed in all patient durings their immediate postoperative intensive care stay before and after fluid loading. Hemodynamic measurements were performed 5 minutes before and immediately after the administration of 500 mL colloidal fluid over 20 minutes.

MEASUREMENTS AND MAIN RESULTS

PCCO, LCCO, FCCO, and NCCO were assessed and compared with cardiac output derived from intermittent transpulmonary thermodilution (ICO). One hundred thirty-two matched sets of data were available for analysis. Bland-Altman analysis using linear mixed effects models with random effects for patient and trial revealed a mean bias ±2 standard deviation (%error) of -0.86 ± 1.41 L/min (34.9%) for PCCO-ICO, -0.26 ± 2.81 L/min (46.3%) for LCCO-ICO, -0.28 ± 2.39 L/min (43.7%) for FCCO-ICO, and -0.93 ± 2.25 L/min (34.6%) for NCCO-ICO. Bland-Altman plots without adjustment for repeated measurements and replicates yielded considerably larger limits of agreement. Trend analysis for all techniques did not meet criteria for acceptable performance.

CONCLUSIONS

All 4 tested devices using pulse wave analysis for measuring cardiac output failed to meet current criteria for meaningful and adequate accuracy, precision, and trending ability in cardiac output monitoring.

Journal of Clinical Monitoring and Computing 2016 end of year summary: cardiovascular and hemodynamic monitoring

The assessment and optimization of cardiovascular and hemodynamic variables is a mainstay of patient management in the care for critically ill patients in the intensive care unit (ICU) or the operating room (OR). It is, therefore, of outstanding importance to meticulously validate technologies for hemodynamic monitoring and to study their applicability in clinical practice and, finally, their impact on treatment decisions and on patient outcome. In this regard, the Journal of Clinical Monitoring and Computing (JCMC) is an ideal platform for publishing research in the field of cardiovascular and hemodynamic monitoring. In this review, we highlight papers published last year in the JCMC in order to summarize and discuss recent developments in this research area.

Autocalibrating pulse contour analysis based on radial artery applanation tonometry for continuous non-invasive cardiac output monitoring in intensive care unit patients after major gastrointestinal surgery--a prospective method comparison study

The T-Line(®) system (Tensys(®) Medical Inc., San Diego, CA, USA) non-invasively estimates cardiac output (CO) using autocalibrating pulse contour analysis of the radial artery applanation tonometry-derived arterial waveform. We compared T-Line CO measurements (TL-CO) with invasively obtained CO measurements using transpulmonary thermodilution (TDCO) and calibrated pulse contour analysis (PC-CO) in patients after major gastrointestinal surgery. We compared 1) TL-CO versus TD-CO and 2) TL-CO versus PC-CO in 27 patients treated in the intensive care unit (ICU) after major gastrointestinal surgery. For the assessment of TD-CO and PC-CO we used the PiCCO(®) system (Pulsion Medical Systems SE, Feldkirchen, Germany). Per patient, we compared two sets of TD-CO and 30 minutes of PC-CO measurements with the simultaneously recorded TL-CO values using Bland-Altman analysis. The mean of differences (± standard deviation; 95% limits of agreement) between TL-CO and TD-CO was -0.8 (±1.6; -4.0 to +2.3) l/minute with a percentage error of 45%. For TL-CO versus PC-CO, we observed a mean of differences of -0.4 (±1.5; -3.4 to +2.5) l/minute with a percentage error of 43%. In ICU patients after major gastrointestinal surgery, continuous non-invasive CO measurement based on autocalibrating pulse contour analysis of the radial artery applanation tonometry-derived arterial waveform (TL-CO) is feasible in a clinical study setting. However, the agreement of TL-CO with TD-CO and PC-CO observed in our study indicates that further improvements are needed before the technology can be recommended for clinical use in these patients.

Assessment of volume status and fluid responsiveness in the emergency department: a systematic approach

When treating acutely ill patients in the emergency department (ED), the successful management of a variety of medical conditions, such as sepsis, acute kidney injury, and pancreatitis, is highly dependent on the correct assessment and optimization of a patient's intravascular volume status. Therefore, it is crucial that the ED physician knows and uses available means to assess intravascular volume status to adequately guide fluid therapy. This review focuses on techniques for volume status assessment that are available in the ED including basic clinical and laboratory findings, apparatus-based tests such as sonography and chest x-ray, and functional tests to evaluate fluid responsiveness. Furthermore, we provide an outlook on promising innovative, noninvasive technologies that might be used for advanced hemodynamic monitoring in the ED.

[Goal-directed hemodynamic therapy: Concepts, indications and risks]

Goal-directed hemodynamic therapy is becoming increasingly more interesting for anesthesiologists and intensive care physicians. Meta-analyses of studies evaluating perioperative therapy algorithms demonstrated a reduction of postoperative morbidity compared to the previous clinical practices. In this review article the basic concepts of goal-directed hemodynamic therapy and the principles of previously employed therapy algorithms are described and discussed. Furthermore, the questions of how these therapy strategies can be transferred into daily clinical practice and whether these therapeutic approaches might even bear risks for patients are elucidated.