Role of Internal Jugular Vein Ultrasound Measurements in the Assessment of Central Venous Pressure in Spontaneously Breathing Patients: A Systematic Review

BACKGROUND

Few studies have tested the role of the internal jugular vein (IJV) ultrasonographic (US) diameters in the assessment of central venous pressure (CVP) in spontaneously breathing patients. No review or meta-analysis is currently available on the role of IJV assessment in this setting. The aim of this systematic review is to check the reliability and accuracy of IJV US diameters in predicting CVP and to evaluate its correlation with CVP in spontaneously breathing patients.

METHODS

This systematic review was based on the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. We included studies on the accuracy and reliability of the IJV ultrasound measures and studies exploring its correlation with CVP in adult spontaneously breathing patients. The studies' report quality was assessed by Standards for Reporting of Diagnostic Accuracy (STARD) and Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 scales.

RESULTS

A total of five studies was eligible for final analysis. The studies on IJV ultrasound measures showed a good quality in reporting. The anterior-posterior diameter maximum of IJV (AP-IJV Dmax) showed the best correlation with the CVP with a good inter-rater reliability and validity in predicting CVP. All measures showed good inter-rater reliability and validity in predicting CVP, but only the AP-IJV Dmax showed good correlation with CVP.

CONCLUSIONS

The AP-IJV Dmax could be a potential surrogate of CVP because of its good reliability and validity in predicting CVP value and its fair-moderate correlation with CVP. Anyway, further research should confi rm these conclusions.

Dressler's syndrome: are we underdiagnosing what we think to be rare?

A 46-year-old man was admitted to the emergency department with fever and pleuritic thoracic pain. Six weeks prior to admission, the patient had undergone cardiac surgery. The ECG showed diffuse ST segment elevation and PR segment depression. The blood tests revealed increased inflammatory markers and negative myocardial necrosis markers. Pericardial and left-sided pleural effusion were noted. Sterile blood cultures were negative. Hence, the hypothesis of Dressler's syndrome was established. The patient improved clinically and analytically with a short course of anti-inflammatory therapy and was discharged with colchicine and acetylsalicylic acid. A thoracic radiography performed 2 months after showed complete remission of pleural effusion.

Respiratory Variations in Electrocardiographic R-Wave Amplitude during Acute Hypovolemia Induced by Inferior Vena Cava Clamping in Patients Undergoing Liver Transplantation

The aim of this study was to analyze whether the respiratory variation in electrocardiogram (ECG) standard lead II R-wave amplitude (ΔRDII) could be used to assess intravascular volume status following inferior vena cava (IVC) clamping. This clamping causes an acute decrease in cardiac output during liver transplantation (LT). We retrospectively compared ΔRDII and related variables before and after IVC clamping in 34 recipients. Receiver operating characteristic (ROC) curve and area under the curve (AUC) analyses were used to derive a cutoff value of ΔRDII for predicting pulse pressure variation (PPV). After IVC clamping, cardiac output significantly decreased while ΔRDII significantly increased (p = 0.002). The cutoff value of ΔRDII for predicting a PPV >13% was 16.9% (AUC: 0.685) with a sensitivity of 57.9% and specificity of 77.6% (95% confidence interval 0.561 – 0.793, p = 0.015). Frequency analysis of ECG also significantly increased in the respiratory frequency band (p = 0.016). Although significant changes in ΔRDII during vena cava clamping were found at norepinephrine doses <0.1 µg/kg/min (p = 0.032), such changes were not significant at norepinephrine doses >0.1 µg/kg/min (p = 0.093). ΔRDII could be a noninvasive dynamic parameter in LT recipients presenting with hemodynamic fluctuation. Based on our data, we recommended cautious interpretation of ΔRDII may be requisite according to vasopressor administration status.

Minimal volume ventilation during robotically assisted mitral valve surgery

INTRODUCTION

A minimal volume ventilation method for robotically assisted mitral valve surgery is described in this study. In an attempt to reduce postoperative pulmonary dysfunction, 40 of 174 patients undergoing robotically assisted mitral valve surgery were ventilated with a small tidal volume during cardiopulmonary bypass.

METHODS

After propensity score matching, 31 patients with minimal volume ventilation were compared with 54 patients with no ventilation. Total ventilation time, PaO₂/FiO₂ ratio, arterial lactate concentration, and the rate of unilateral pulmonary edema in the matched minimal ventilation and standard treatment groups were evaluated.

RESULTS

Patients in the minimal ventilation group had shorter ventilation times, 12.0 (interquartile range: 9.9-15.0) versus 14.0 (interquartile range: 12.0-16.3) hours (p = 0.036), and lower postoperative arterial lactate levels, 0.99 (interquartile range: 0.81-1.39) versus 1.28 (interquartile range: 0.99-1.86) mmol/L (p = 0.01), in comparison to patients in the standard treatment group. There was no difference in postoperative PaO₂/FiO₂ ratio levels or in the rate of unilateral pulmonary edema between the groups.

CONCLUSION

Minimal ventilation appeared beneficial in terms of total ventilation time and blood lactatemia, while there was no improvement in arterial blood gas measurements or in the rate of unilateral pulmonary edema. The lower postoperative arterial lactate levels may suggest improved lung perfusion among patients in the minimal volume ventilation group. The differences in the ventilation times were in fact small, and further studies are required to confirm the possible advantages of the minimal volume ventilation method in robotically assisted cardiac surgery.

A Narrative Review on Thrombolytics in Advanced CKD: Is it an Evidence-Based Therapy?

PURPOSE

A timely pharmacoinvasive strategy consisting of thrombolytic therapy (TT) plays a pivotal role in three major scenarios: acute ischemic stroke (AIS), acute myocardial infarction (STEMI), and massive pulmonary embolism (PE). Presence of advanced chronic kidney disease (CKD) (estimated glomerular filtration rate < 30 mL/min/1.73 m2), known to disturb thrombotic/thrombolytic equilibrium, causes difficulties for clinicians in evaluating risk-benefit balance, as current guidelines do not address the relationship between TT and the advanced CKD. This narrative review aims to evaluate the most important scientific resources regarding the evidences, benefits, and risks of using thrombolytics in advanced CKD.

METHODS

We searched the electronic database of PubMed for studies evaluating the relationship between renal dysfunction and TT in patients with STEMI, AIS, and massive PE. Randomized controlled trials (RCTs), observational studies including prospective or retrospective cohort studies, reviews, meta-analyses, and guidelines were included if referring to TT for one of the three scenarios in advanced CKD.

RESULTS

Prothrombotic conditions in CKD, associated with an increased risk of hemorrhages, can affect the safety and efficacy of TT. Concerns regarding in-hospital bleeding events and poor clinical outcomes subsequent to TT in advanced CKD continue to cause underutilization or delaying routine reperfusion therapy.

CONCLUSIONS

The impact of TT on the outcomes of advanced CKD patients is poorly understood to date, with scarce data available in current guidelines and conflicting results from observational studies. Until evidence-based data from RCTs will be obtained, the clinical challenge of maximizing benefits for this high-risk subgroup lays in the hands of practicing clinicians.

Composed endotypes to guide antibiotic discontinuation in sepsis

Overuse of empiric antibiotic therapy in the ICU is responsible for promoting the dissemination of multidrug-resistant (MDR) bacteria. Shortened antibiotic treatment duration could contribute to palliating the emergence of MDR. Uncertainty about patient evolution is a major concern for deciding to stop antibiotics. Biomarkers could represent a complementary tool to identify those patients for whom antibiotic treatment could be safely discontinued. The biomarker most extensively studied to guide antibiotic withdrawal is procalcitonin (PCT), but its real impact on decreasing the duration of antibiotic treatment is a matter of controversy. Combining biomarkers to rule out complicated outcomes in sepsis patients could represent a better option. Some candidate biomarkers, including mid-regional proadrenomedullin, the percentage of human leukocyte antigen DR (HLA-DR)-positive monocytes, means of fluorescence intensities of HLA-DR on monocytes, interleukin-7 receptor expression levels, immunoglobulin M levels in the serum or the absence of increased proteolysis, have already demonstrated the potential to exclude the risk of progression to septic shock, nosocomial infections, and mortality when tested along the sepsis course. Other promising biomarkers to rule out complicated outcomes are neutrophil protease activity, the adaptive/coagulopathic signatures identified by whole transcriptome analysis by Sweeney et al., and the SRS1 signature identified by Davenport et al. In conclusion, there are a number of promising biomarkers involved in proteolytic, vascular, immunological, and coagulation alterations that could be useful to build composed endotypes to predict uncomplicated outcomes in sepsis. These endotypes could help to identify patients deserving the discontinuation of antibiotics.

Prospective, randomized clinical trial comparing use of intraoperative transesophageal echocardiography to standard care during radical cystectomy

Purpose:

Our prospective, randomized clinical study aims to evaluate the utility of intraoperative transesophageal echocardiography (TEE) in patients undergoing radical cystectomy.

Materials and Methods:

Eighty patients were randomized to a standard of care group or the intervention group that received continuous intraoperative TEE. Data are presented as means ± standard deviations, median (25^th percentile, 75^th percentile), or numbers and percentages. Characteristics were compared between groups using independent sample t-tests, Wilcoxon–Mann–Whitney tests or Chi-square tests, as appropriate. All tests were two-sided and P < 0.05 was considered to indicate statistical significance.

Results:

Both groups had similar preoperative demographic characteristics. There was a significant difference between central line insertion with all insertions in the control group (15%, 6 vs. 0%, 0; P < 0.003). Of all the perioperative complications, 80% occurred in the control group versus 20% in the TEE group, with 21% of controls experiencing a cardiac or pulmonary complication compared to 5% in the TEE group (8 vs. 2, P < 0.04). The control group patients were more likely to have adverse cardiac complications than the TEE group (15%, 6 vs. 3%, 1; P < 0.040). Postoperative cardiac arrhythmia was observed only in the control group (13%, 5 vs. 0%, 0; P <.007). Prolonged intubation was only observed in the control group (10%, 4 vs. 0%, 0; P < 0.017).

Conclusion:

TEE can be a useful monitoring tool in patients undergoing radical cystectomy, limiting the use of central line insertion and potentially translating into earlier extubation and decreased postoperative cardiac morbidities.

Inferior vena cava diameter measurements and BUN/creatinine values to determine dehydration in patients with hip fractures preoperatively: A prospective observational study

Dehydration is a common problem in patients undergoing hip fracture surgery. Sonographic inferior vena cava (IVC) diameter measurement evaluates to estimate volume status. The aim of the study to evaluate the relationship between IVC measurements (expiratory diameter of IVC, collabsibility index [CI], inspiratory diameter of IVC) and blood urea nitrogen (BUN)/creatinine ratio in patients undergoing hip fracture surgery. Ultrasonography of IVC was performed on 35 patients underwent hip fracture surgery. The end-expiratory diameter of IVC, end-inspiratory diameter of IVC, and CI were assessed preoperatively. The patients were classified as group 1 for BUN/Cr ratio <20, group 2 for BUN/Cr ratio of >20. Sonographic IVC measurement was not successful in 14.2% of patients and 30 patients remained. The mean age was 80.43 ± 11.10 (58-95) years. The IVC diameter values had no discriminatory value for the prediction of dehydration according to BUN/creatinine ratio (P > .05). Receiver operating characteristic curve indicated that area under the curve (AUC) for CI: 49.5%, (95% CI 26.5-72.5) P > .05; for IVC inspiratory diameter: AUC: 43.3%, (95% CI, 19.9-66.6) P > .05; for IVC expiratory diameter: AUC: 45.5%, (95% CI, 26.6-65.4) P > .05. No correlations of BUN/creatinine ratio with CI and IVC expiratory diameter were found (as r = -0.262 [P = .163]; [r = 0.206, P = .274]; respectively). There were not any correlation in linear regression analysis model between BUN/Cr ratio according to independent variables (Age, CI, IVCmax, IVCmin) (P = .108, P = .419, P = .282, P = .257; respectively). No discriminatory relationship was found between the bedside ultrasonographic measurement of IVC parameters and BUN/creatinine ratio in patients underwent hip fracture surgery to predict the preoperative dehydration.

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.

Gasometric gradients between blood obtained from the pulmonary artery wedge and pulmonary artery positions in pulmonary arterial hypertension

INTRODUCTION

Little is known on the pulmonary gradients of oxyhemoglobin, carboxyhemoglobin and methemoglobin in pulmonary arterial hypertension (PAH). We sought to determine these gradients in group 1 PAH and assess their association with disease severity and survival.

METHODS

During right heart catheterization (RHC) we obtained blood from pulmonary artery (PA) and pulmonary artery wedge (PAW) positions and used co-oximetry to test their gasometric differences.

RESULTS

We included a total of 130 patients, 65 had group 1 PAH, 40 had pulmonary hypertension (PH) from groups 2-5 and 25 had no PH during RHC. In all groups, PAW blood had higher pH, carboxyhemoglobin and lactate as well as lower pCO2 than PA blood. In group 1 PAH (age 58 ± 15 years, 72% females), methemoglobin in the PAW was lower than in the PA blood (0.83% ± 0.43 vs 0.95% ± 0.50, p = 0.03) and was directly associated with the degree of change in pulmonary vascular resistance (R = 0.35, p = 0.02) during inhaled nitric oxide test. Oxyhemoglobin in PA (HR (95%CI): 0.90 (0.82-0.99), p = 0.04) and PAW (HR (95%CI): 0.91 (0.84-0.98), p = 0.003) blood was associated with adjusted survival in PAH.

CONCLUSIONS

Marked differences were observed in the gasometric determinations between PAW and PA blood. The pulmonary gradient of methemoglobin was lower in PAH patients compared to controls and a higher PAW blood methemoglobin was associated with a more pronounced pulmonary vascular response to inhaled nitric oxide. Pulmonary artery and PAW oxyhemoglobin tracked with disease severity and survival in PAH.

Utility of transpulmonary thermodilution with Pulse Index Continuous Cardiac Output system for hemodynamic assessment in a hemodialysis patient with arteriovenous fistula and continuous renal replacement therapy: A case report

Close hemodynamic monitoring is crucial for the patients to guide cardiovascular therapy for the optimal management. Transpulmonary thermodilution offers a less invasive hemodynamic monitoring with Pulse Index Continuous Cardiac Output system analysis. Intracardiac shunts have been associated with well-defined alterations in transpulmonary thermodilution-related hemodynamic parameters leading to inaccurate measurements and therefore are among the contraindications for transpulmonary thermodilution. However, data on the effects of arteriovenous fistulas as well as extracorporeal circuits on the thermodilution curves remain limited and inconclusive. Herein, we report generation of modified thermodilution curve forms leading to incorrect calculation of thermodilution-derived hemodynamic parameters by Pulse Index Continuous Cardiac Output system in a female patient in the presence of Continuous Veno-Venous Hemodiafiltration and a high flow arteriovenous fistula. Our findings revealed generation of modified thermodilution curves and unacceptably high extravascular lung water readings by Pulse Index Continuous Cardiac Output system. This seems consistent with early recirculation of cold indicator in case of a peripheral shunt emphasizing the potential impact of high flow arteriovenous fistula on reliability of transpulmonary thermodilution measurements in critically ill patients, limiting the use of Pulse Index Continuous Cardiac Output system in these conditions.

Efficacy of Stroke Volume Variation, Cardiac Output and Cardiac Index as Predictors of Fluid Responsiveness using Minimally Invasive Vigileo Device in Intracranial Surgeries

Introduction:

Functional hemodynamic monitoring using dynamic parameters such as stroke volume variations (SVVs) based on pulse contour analysis is considered more accurate than central venous pressure and mean arterial pressure (MAP) in predicting fluid responsiveness. New device, i.e., Vigileo system, allows automatic and continuous monitoring of cardiac output (CO) based on pulse contour analysis and respiratory stroke volume.

Aim:

The study aims to test the above hypothesis using graded volume loading step (VLS) to assess the accuracy of SVV as a predictor of fluid responsiveness in patients undergoing intracranial surgery.

Materials and Methods:

After taking ethical committee approval and informed consent, 60 patients aged between 18 and 55 years belonging to the American Society of Anesthesiologists physical status Class I and II, of either sex, scheduled for brain surgery were included in the study. In this study, 5 min after intubation, with stable hemodynamics, patients received volume loading in successive steps (VLS) of 200 ml of lactated Ringer's solution until the stroke volume increased to <10%. Blood pressure (BP), heart rate (HR), stroke volume (SV), and SVV were measured before and after each VLS. Optimal preload augmentation required by each patient was measured by the number of VLS after which an increase in SV was <10%.

Results:

There was a significant decrease in the baseline BP and SV in responsive and nonresponsive groups for the first VLS, but there is no change in HR statistically. There was a significant change in SV after first VLS. Receiver operating characteristic analysis showed a larger area under the curve of 0.758 for SVV compared to other measured variables. The median number of VLS administered were 2 per patient equating to a mean ± SD requirement of 368 ± 176 ml of crystalloid per patient as the optimal preoperative infusion volume.

Conclusion:

SVV is a better predictor of preload responsiveness measured with third-generation Vigileo device when compared to BP and HR.

Photoplethysmographic characterization of vascular tone mediated changes in arterial pressure: an observational study

To determine whether a classification based on the contour of the photoplethysmography signal (PPGc) can detect changes in systolic arterial blood pressure (SAP) and vascular tone. Episodes of normotension (SAP 90-140 mmHg), hypertension (SAP > 140 mmHg) and hypotension (SAP < 90 mmHg) were analyzed in 15 cardiac surgery patients. SAP and two surrogates of the vascular tone, systemic vascular resistance (SVR) and vascular compliance (Cvasc = stroke volume/pulse pressure) were compared with PPGc. Changes in PPG amplitude (foot-to-peak distance) and dicrotic notch position were used to define 6 classes taking class III as a normal vascular tone with a notch placed between 20 and 50% of the PPG amplitude. Class I-to-II represented vasoconstriction with notch placed > 50% in a small PPG, while class IV-to-VI described vasodilation with a notch placed < 20% in a tall PPG wave. 190 datasets were analyzed including 61 episodes of hypertension [SAP = 159 (151-170) mmHg (median 1st-3rd quartiles)], 84 of normotension, SAP = 124 (113-131) mmHg and 45 of hypotension SAP = 85(80-87) mmHg. SAP were well correlated with SVR (r = 0.78, p < 0.0001) and Cvasc (r = 0.84, p < 0.0001). The PPG-based classification correlated well with SAP (r = - 0.90, p < 0.0001), SVR (r = - 0.72, p < 0.0001) and Cvasc (r = 0.82, p < 0.0001). The PPGc misclassified 7 out of the 190 episodes, presenting good accuracy (98.4% and 97.8%), sensitivity (100% and 94.9%) and specificity (97.9% and 99.2%) for detecting episodes of hypotension and hypertension, respectively. Changes in arterial pressure and vascular tone were closely related to the proposed classification based on PPG waveform.Clinical Trial Registration NTC02854852.

Identification of return of spontaneous circulation during cardiopulmonary resuscitation via pulse oximetry in a porcine animal cardiac arrest model

In this prospective study we investigated whether the pulse oximetry plethysmographic waveform (POP) could be used to identify return of spontaneous circulation (ROSC) during cardio-pulmonary resuscitation (CPR). Tweleve pigs (28 ± 2 kg) were randomly assigned to two groups: Group I (non-arrested with compressions) (n = 6); Group II (arrested with CPR and defibrillation) (n = 6). Hemodynamic parameters and POP were collected and analyzed. POP was analyzed using both a time domain method and a frequency domain method. In Group I, when compressions were carried out on subjects with a spontaneous circulation, a hybrid fluctuation or "envelope" phenomenon appeared in the time domain method and a "double" or "fusion" peak appeared in the frequency domain method. In Group II, after the period of ventricular fibrillation was induced, the POP waveform disappeared. With compressions, POP showed a regular compression wave. After defibrillation, ROSC, and continued compressions, a hybrid fluctuation or "envelope" phenomenon appeared in the time domain method and a "double" or "fusion" peak appeared in the frequency domain method, similar to Group I. Analysis of POP using the time and frequency domain methods could be used to identify ROSC during CPR.

Development and In Silico Evaluation of a Model-Based Closed-Loop Fluid Resuscitation Control Algorithm

OBJECTIVE

To develop and evaluate in silico a model-based closed-loop fluid resuscitation control algorithm via blood volume feedback.

METHODS

Model-based adaptive control algorithm for fluid resuscitation was developed by leveraging a low-order lumped-parameter blood volume dynamics model, and then in silico evaluated based on a detailed mechanistic model of circulatory physiology. The algorithm operates in two steps: (1) the blood volume dynamics model is individualized based on the patient's fractional blood volume response to an initial fluid bolus via system identification; and (2) an adaptive control law built on the individualized blood volume dynamics model regulates the blood volume of the patient.

RESULTS

The algorithm was able to track the blood volume set point as well as accurately estimate and monitor the patient's absolute blood volume level. The algorithm significantly outperformed a population-based proportional-integral-derivative control.

CONCLUSION

Model-based development of closed-loop fluid resuscitation control algorithm may enable regulation of blood volume and monitoring of absolute blood volume level.

SIGNIFICANCE

Model-based closed-loop fluid resuscitation algorithm may offer opportunities for standardized and patient-tailored therapy and reduction of clinician workload.

Artificial liver support systems: what is new over the last decade?

The liver is a complex organ that performs vital functions of synthesis, heat production, detoxification and regulation; its failure carries a highly critical risk. At the end of the last century, some artificial liver devices began to develop with the aim of being used as supportive therapy until liver transplantation (bridge-to-transplant) or liver regeneration (bridge-to-recovery). The well-recognized devices are the Molecular Adsorbent Recirculating System™ (MARS™), the Single-Pass Albumin Dialysis system and the Fractionated Plasma Separation and Adsorption system (Prometheus™). In the following years, experimental works and early clinical applications were reported, and to date, many thousands of patients have already been treated with these devices. The ability of artificial liver support systems to replace the liver detoxification function, at least partially, has been proven, and the correction of various biochemical parameters has been demonstrated. However, the complex tasks of regulation and synthesis must be addressed through the use of bioartificial systems, which still face several developmental problems and very high production costs. Moreover, clinical data on improved survival are conflicting. This paper reviews the progress achieved and new data published on artificial liver support systems over the past decade and the prospects for these devices.

Using extra systoles and the micro-fluid challenge to predict fluid responsiveness during cardiac surgery

Fluid responsiveness prediction is difficult during cardiac surgery. The micro-fluid challenge (micro-FC; rapid central infusion of 50 ml) and the extrasystolic method utilising post-extrasystolic preload increases may predict fluid responsiveness. Two study windows during coronary artery bypass graft surgery were defined, 1: After anaesthesia induction until surgical incision, 2: Left internal mammarian artery surgical preparation period. Each window consisted of 10-15 min observation for extrasystoles before a micro-FC was performed, after which a traditional fluid challenge (FC) was performed (5 ml/kg). Extrasystolic and micro-FC induced changes in hemodynamic variables were derived as predictors of fluid responsiveness defined as stroke volume increasing > 10% following FC. 61 patients were studied. Post-ectopic changes in pulse pressure (PP) predicted fluid responsiveness with receiver operating characteristic area (AUC) of 0.69 [CI 0.40;0.97] in the first study window and 0.64 [0.44;0.86] in the second window. Other post-ectopic predictors such as pre-ejection period (PEP) and systolic blood pressure (SBP) had similar or lower AUCs. Heart rate was 52.9 (SD ±8.4) min^- 1 and 53.6 (± 8.8) min^- 1 in the two study windows. Micro-FC induced changes in PEP had AUC of 0.74 [0.57;0.90] in the first window and 0.60 [0.40;0.76] in the second window. Correcting micro-FC induced changes in PEP for the micro-FC induced changes in heart rate had AUCs of 0.84 [0.70;0.97] in the first window and 0.63 [0.47;0.79] in the second window. The investigated methods revealed insufficient validity during cardiac surgery. RR interval corrected changes during a micro-FC should be investigated further. Trial registration Clinicaltrials.gov: NCT03002129.

Correlation between urinary albumin to creatinine ratio and systemic glycocalyx degradation in pediatric sepsis

Background: Increased capillary permeability in sepsis is associated with several complications and worse outcomes. Glycocalyx degradation, marked by increased serum syndecan-1 levels, alters vascular permeability, which can manifest as albuminuria in the glomerulus. Therefore, elevated urinary albumin to creatinine ratio (ACR) potentially provides an index of systemic glycocalyx degradation. The aim of this study was to analyze the correlation between urinary ACR and serum syndecan-1 levels.Methods: A longitudinal prospective study with repeated cross-sectional design was conducted on children with sepsis in pediatric intensive care unit, we evaluated serum syndecan-1 levels and urinary ACR on days 1, 2, 3, and 7. A descriptive study on healthy children was also conducted to determine the reference value of syndecan-1 in children.Results: 49 subjects with sepsis were recruited. Based on the data of the healthy children group (n=30), syndecan-1 level of >90th percentile (41.42 ng/mL) was defined as systemic glycocalyx degradation. The correlation coefficients (r) between urinary ACR and syndecan-1 levels were 0.32 (p<0.001) from all examination days (162 specimens), 0.298 (p=0.038) on day 1, and 0.469 (p=0.002) on day 3. The area under the curve of urinary ACR and systemic glycocalyx degradation was 65.7% (95% CI 54.5%–77%; p=0.012). Urinary ACR ≥157.5 mg/g was determined as the cut-off point for glycocalyx degradation, with a sensitivity of 77.4% and a specificity of 48%.Conclusion: Urinary ACR showed a weak correlation with systemic glycocalyx degradation, indicating that the pathophysiology of elevated urinary ACR in sepsis is not merely related to glycocalyx degradation.

Non-invasive monitoring using photoplethysmography technology

We evaluated the accuracy and precision of a novel non-invasive monitoring device in comparison with conventional monitoring methods used in intensive care units (ICU). The study device was developed to measure blood pressure, pulse rate, respiratory rate, and oxygen saturation, continuously with a single sensor using the photoplethysmographic technique. Patients who were monitored with arterial pressure lines in the ICU were enrolled. Systolic and diastolic blood pressure, pulse rate, respiratory rate, and arterial oxygen saturation were measured continuously for 30 min at 5-min intervals using the conventional methods and the study device. The primary outcome variable was blood pressure. Blood pressure measured by the study device highly correlated with the arterial pressure line values (correlation coefficients > 0.95). Percent errors for systolic, diastolic and mean blood pressures were 2.4% and 6.7% and 6.5%, respectively. Percent errors for pulse rate, respiratory rate and oxygen saturation were 3.4%, 5.6% and 1.4%, respectively. The non-invasive, continuous, multi-parameter monitoring device presented high level of agreement with the invasive arterial blood pressure monitoring, along with sufficient accuracy and precision in the measurements of pulse rate, respiratory rate, and oxygen saturation.

Established and novel pathophysiological mechanisms of pericardial injury and constrictive pericarditis

This review article aims to: (1) discern from the literature the immune and inflammatory processes occurring in the pericardium following injury; and (2) to delve into the molecular mechanisms which may play a role in the progression to constrictive pericarditis. Pericarditis arises as a result of a wide spectrum of pathologies of both infectious and non-infectious aetiology, which lead to various degrees of fibrogenesis. Current understanding of the sequence of molecular events leading to pathological manifestations of constrictive pericarditis is poor. The identification of key mechanisms and pathways common to most fibrotic events in the pericardium can aid in the design and development of novel interventions for the prevention and management of constriction. We have identified through this review various cellular events and signalling cascades which are likely to contribute to the pathological fibrotic phenotype. An initial classical pattern of inflammation arises as a result of insult to the pericardium and can exacerbate into an exaggerated or prolonged inflammatory state. Whilst the implication of major drivers of inflammation and fibrosis such as tumour necrosis factor and transforming growth factor β were foreseeable, the identification of pericardial deregulation of other mediators (basic fibroblast growth factor, galectin-3 and the tetrapeptide Ac-SDKP) provides important avenues for further research.

Evaluation of pulse pressure variation and pleth variability index to predict fluid responsiveness in mechanically ventilated isoflurane-anesthetized dogs

OBJECTIVE

To evaluate whether pulse pressure variation (PPV) and pleth variability index (PVI) are more accurate than central venous pressure (CVP) for predicting fluid responsiveness in mechanically ventilated isoflurane-anesthetized dogs after premedication with acepromazine.

DESIGN

Prospective experimental trial.

SETTING

University teaching hospital.

ANIMALS

Twelve Harrier hound dogs.

INTERVENTIONS

Each dog was anesthetized and had a fluid challenge performed. This was repeated 4 weeks later for a total of 24 fluid challenges. After premedication with intramuscular acepromazine, anesthesia was induced with propofol and maintained with isoflurane. The dogs were mechanically ventilated with constant settings. The fluid challenge consisted of 10 mL/kg of 6% hydroxyethyl starch intravenously over 13 minutes.

MEASUREMENTS AND MAIN RESULTS

Before and after the fluid challenge, PPV, PVI, CVP, and other hemodynamics were recorded. Change in velocity time integral of pulmonary arterial blood flow by echocardiography was calculated as an indication of change in stroke volume. A fluid responder was defined as an increase in velocity time integral ≥ 15%. Receiver operator characteristic (ROC) curves were used to determine cutoff values. Areas under ROC curve were calculated and compared. Dogs responded on 14 fluid challenges and did not on 10. Cutoff values for PPV and PVI were 11% (sensitivity 79%; specificity 80%) and 9.3% (sensitivity 86%; specificity 70%), respectively. The areas under the ROC curve of PPV [0.85, 95% confidence interval (CI): 0.70-1.00, P = 0.038] and PVI (0.84, 95% CI: 0.68-1.00, P = 0.043) were significantly higher than CVP (0.56, 95% CI: 0.32-0.81).

CONCLUSIONS

PPV and PVI predicted fluid responsiveness more accurately than CVP and may be useful to guide fluid administration in mechanically ventilated isoflurane-anesthetized dogs after premedication with acepromazine.

Cardiopulmonary monitoring of shock

PURPOSE OF REVIEW

We will briefly review the classification of shock and the hallmark features of each subtype. Available modalities for monitoring shock patients will be discussed, along with evidence supporting the use, common pitfalls, and practical considerations of each method.

RECENT FINDINGS

As older, invasive monitoring methods such as the pulmonary artery catheter have fallen out of favor, newer technologies for cardiac output estimation, echocardiography, and noninvasive tests such as passive leg raising have gained popularity. Newer forms of minimally invasive or noninvasive monitoring (such as pulse contour analysis and chest bioreactance) show promise but will need further investigation before they are considered validated for practical use. There remains no 'ideal' test or standard of care for cardiopulmonary monitoring of shock patients.

SUMMARY

Shock has potentially reversible causes of morbidity and mortality if appropriately diagnosed and managed. Older methods of invasive monitoring have significant limitations but are still critical for managing shock in certain patients and settings. Newer methods are easier to employ, but further validation is needed. Multiple modalities along with careful clinical assessment are often useful in distinguishing shock subtypes. Best practice standards for monitoring should be based on institutional expertise.

Extravascular lung water measurements in acute respiratory distress syndrome: why, how, and when?

PURPOSE OF REVIEW

Increase in pulmonary vascular permeability accompanied with accumulation of excess extravascular lung water (EVLW) is the hallmark of acute respiratory distress syndrome (ARDS). Currently, EVLW and pulmonary vascular permeability index (PVPI) can be quantitatively measured using the transpulmonary thermodilution (TPTD) technique. We will clarify why, how, and when EVLW and PVPI measurements should be performed.

RECENT FINDINGS

Although the Berlin criteria of ARDS are simple and widely used, several criticisms of them have been published. The last 2 decades have witnessed the introduction and evolution of the TPTD technique for measuring EVLW and PVPI. Several publications have recommended to evaluate EVLW and the PVPI during the treatment of critically ill patients. Accurate and objective diagnoses can be made for ARDS patients using EVLW and PVPI. EVLW more than 10 ml/kg is a reasonable criterion for pulmonary edema, and EVLW more than 15 ml/kg for a severe condition. In addition to EVLW more than 10 mL/kg, PVPI more than three suggests increased vascular permeability (i.e., ARDS), and PVPI less than 2 represent normal vascular permeability (i.e., cardiogenic pulmonary edema).

SUMMARY

EVLW and PVPI measurement will open the door to future ARDS clinical practice and research, and have potential to be included in the future ARDS definition.

A comparison of ventricular systolic function indices provided by VolumeView/EV1000™ and left ventricular ejection fraction by echocardiography among septic shock patients

The aim of this study was to compare the cardiac function index (CFI) and global ejection fraction (GEF) obtained by VolumeView/EV1000™, with the left ventricular ejection fraction (LVEF) by echocardiography in septic shock patients. A prospective observational study was conducted in a medical intensive care unit of a tertiary, teaching university hospital. Thirty-two, mechanical-ventilated septic shock patients were included in this study. We simultaneously measured CFI and GEF with LVEF. The correlation of CFI, GEF along with LVEF and ability of CFI and GEF to predict LVEF ≥ 40, 50 and 60% were evaluated. There were 192 pairs of CFI, GEF and LVEF. CFI was significantly correlated with GEF (r = 0.82, P < 0.0001). A significant correlation was observed between CFI and LVEF (r = 0.56, P < 0.0001) and GEF and LVEF (r = 0.71, P < 0.0001). The CFI and GEF had a good predictive ability for estimating LVEF ≥ 40, 50 and 60%, with an area under receiving operating characteristic (AUC) 0.875-0.934. The CFI ≥ 3/min predicted LVEF ≥ 40% with sensitivity 95.1% and specificity 48.3%. The GEF ≥ 15%, estimated LVEF ≥ 40% with sensitivity 92.6% and specificity 69%. There were 40 thermodilution and LVEF measurements obtained before and after norepinephrine adjustment. Blood pressure as well as the cardiac index were significantly increased, whereas there were no changes in CFI, GEF and LVEF values. Conclusions: Both CFI and GEF obtained by VolumeView/EV1000™, correlated with LVEF, so as to provide a reliable estimation of LV systolic function in septic shock patients.

Cardiac output measurement in liver transplantation patients using pulmonary and transpulmonary thermodilution: a comparative study

During liver transplantation surgery, the pulmonary artery catheter-despite its invasiveness-remains the gold standard for measuring cardiac output. However, the new EV1000 transpulmonary thermodilution calibration technique was recently introduced into the market by Edwards LifeSciences. We designed a single-center prospective observational study to determine if these two techniques for measuring cardiac output are interchangeable in this group of patients. Patients were monitored with both pulmonary artery catheter and the EV1000 system. Simultaneous intermittent cardiac output measurements were collected at predefined steps: after induction of anesthesia (T1), during the anhepatic phase (T2), after liver reperfusion (T3), and at the end of the surgery (T4). The 4-quadrant and polar plot techniques were used to assess trending ability between the two methods. We enrolled 49 patients who underwent orthotopic liver transplantation surgery. We analyzed a total of 588 paired measurements. The mean bias between pulmonary artery catheter and the EV1000 system was 0.35 L/min with 95% limits of agreement of - 2.30 to 3.01 L/min, and an overall percentage error of 35%. The concordance rate between the two techniques in 4-quadrant plot analysis was 65% overall. The concordance rate of the polar plot showed an overall value of 83% for all pairs. In the present study, in liver transplantation patients we found that intermittent cardiac output monitoring with EV1000 system showed a percentage error compared with pulmonary artery catheter in the acceptable threshold of 45%. On the others hand, our results showed a questionable trending ability between the two techniques.

Pulmonary hemodynamic effects and pulmonary arterial compliance during hypovolemic shock and reinfusion with human relaxin-2 (serelaxin) treatment in a sheep model

BACKGROUND

Previous studies on the recombinant form of human relaxin-2 (serelaxin) have shown a decrease of pulmonary hemodynamics after serelaxin injection. Currently, the effect of serelaxin treatment during hypovolemia in a large animal model remains mostly unknown.

METHODS

12 sheep were randomly assigned to a sham or serelaxin (30μg/kg serelaxin) group and underwent right heart catheterization. 50% of the estimated total blood volume were removed to induce hypovolemia, and subsequently retransfused 20 min later (reinfusion). Blood gases, heart rate, peripheral and pulmonary arterial oxygen saturation, systolic, diastolic and mean values of both pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCW) were measured. Cardiac output (CO), pulmonary vascular resistance (PVR), pulmonary arterial compliance (PAcompl) and systemic vascular resistance (SVR) were calculated.

RESULTS

Hypovolemia and shock led to a similar decrease of PAP and PCW in both groups (p≤0.001). CO, SV and PAcompl decreased only in the control group (p≤0.05) and remained higher in the serelaxin-treated group. The results of this study suggest that serelaxin treatment did not negatively influence hemodynamic parameters during hypovolemic shock.

CONCLUSION

The main conclusion of this study is that cardiopulmonary adaption mechanisms are not critically altered by serelaxin administration during severe hypovolemia and retransfusion.

Cardiovascular Autonomic Response to Orthostatic Stress Under Hypoxia in Patients with Spinal Cord Injury

Huang, Shu-Chun, Kuo-Cheng Liu, Alice M.K. Wong, Shih-Chieh Chang, and Jong-Shyan Wang. Cardiovascular autonomic response to orthostatic stress under hypoxia in patients with spinal cord injury. High Alt Med Biol. 19:201-207, 2018.

AIMS

Determining whether systemic hypoxia aggravates the severity of autonomic cardiovascular dysfunction in orthostatic stress among patients with spinal cord injuries (SCIs).

METHODS

Twenty-four male patients with chronic SCI whose neurological levels were above T6 were recruited. Twenty-five healthy men were enrolled in the control group. Five-minute supine rest (SR) and head-up tilt (HUT) at 60° were performed in normoxia and after 1 hour, 13.5% fraction of inspired O₂ exposure. A noninvasive cardiac output (CO) monitor was used to measure stroke volume (SV), CO, total peripheral resistance (TPR), and blood pressure (BP), whereas heart rate variability (HRV) was performed to determine cardiac autonomic activity. Digital volume pulse analysis was applied to measure arteriolar tone.

RESULTS

In normoxia from SR to HUT, systolic and diastolic BPs declined, SV decreased, and heart rate increased, whereas CO and TPR showed a declining trend in the SCI group. Sympathetic activation and vagal withdrawal were also disclosed in the HRV analysis. In hypoxia, the change of these cardiovascular responses from SR to HUT exhibited no difference to normoxia in the SCI group. No significant difference in arterial desaturation was observed between the two groups (82.9% vs. 80.4%).

CONCLUSIONS

Cardiovascular adaptation to orthostatic stress is not affected by subacute steady-state hypoxia in chronic SCI patients with neurological levels higher than T6.

Finger and forehead photoplethysmography-derived pulse-pressure variation and the benefits of baseline correction

To non-invasively predict fluid responsiveness, respiration-induced pulse amplitude variation (PAV) in the photoplethysmographic (PPG) signal has been proposed as an alternative to pulse pressure variation (PPV) in the arterial blood pressure (ABP) signal. However, it is still unclear how the performance of the PPG-derived PAV is site-dependent during surgery. The aim of this study is to compare finger- and forehead-PPG derived PAV in their ability to approach the value and trend of ABP-derived PPV. Furthermore, this study investigates four potential confounding factors, (1) baseline variation, (2) PPV, (3) ratio of respiration and heart rate, and (4) perfusion index, which might affect the agreement between PPV and PAV. In this work, ABP, finger PPG, and forehead PPG were continuously recorded in 29 patients undergoing major surgery in the operating room. A total of 91.2 h data were used for analysis, from which PAV and PPV were calculated and compared. We analyzed the impact of the four factors using a multiple linear regression (MLR) analysis. The results show that compared with the ABP-derived PPV, finger-derived PAV had an agreement of 3.2 ± 5.1%, whereas forehead-PAV had an agreement of 12.0 ± 9.1%. From the MLR analysis, we found that baseline variation was a factor significantly affecting the agreement between PPV and PAV. After correcting for respiration-induced baseline variation, the agreements for finger- and forehead-derived PAV were improved to reach an agreement of − 1.2 ± 3.8% and 3.3 ± 4.8%, respectively. To conclude, finger-derived PAV showed better agreement with ABP-derived PPV compared to forehead-derived PAV. Baseline variation was a factor that significantly affected the agreement between PPV and PAV. By correcting for the baseline variation, improved agreements were obtained for both the finger and forehead, and the difference between these two agreements was diminished. The tracking abilities for both finger- and forehead-derived PAV still warrant improvement for wide use in clinical practice. Overall, our results show that baseline-corrected finger- and forehead-derived PAV may provide a non-invasive alternative for PPV.

Dynamic arterial elastance measured by uncalibrated pulse contour analysis predicts arterial-pressure response to a decrease in norepinephrine

BACKGROUND

Dynamic arterial elastance (Ea_dyn) has been proposed as an indicator of vascular tone that predicts the decrease in arterial pressure in response to changes in norepinephrine (NE). The purpose of this study was to determine whether Ea_dyn measured by uncalibrated pulse contour analysis (UPCA) can predict a decrease in arterial pressure when the NE dosage is decreased.

METHODS

We conducted a prospective study in a university hospital intensive care unit. Patients with vasoplegic syndrome for whom the intensive care physician planned to decrease the NE dosage were included. Haemodynamic and UPCA (VolumeView and FloTrac; Edwards Lifesciences, Irvine, CA, USA) values were obtained before and after decreasing the NE dosage. Responders were defined by a >10% decrease in mean arterial pressure (MAP).

RESULTS

Of 35 patients included, 11 (31%) were pressure responders with a median decrease of 13%. Ea_dyn was correlated to systolic arterial pressure (SAP) (r=0.255; P=0.033), diastolic arterial pressure (r=0.271; P=0.024), MAP (r=0.310; P=0.009), heart rate (r=0.543; P=0.0001), and transthoracic echography cardiac output (r=0.264; P=0.024). Baseline Ea_dyn was correlated with MAP changes (r=0.394; P=0.019) and SAP changes (r=0.431; P=0.009). Ea_dyn predicted the decrease in arterial pressure with an area under the receiver-operating-characteristic curve of 0.84 (95% confidence interval: 0.70-0.97). The best cut-off was 0.90.

CONCLUSIONS

The present study confirms the ability of Ea_dyn measured by UPCA to predict an arterial pressure response to a decrease in NE. Ea_dyn may constitute an easy-to-use functional approach to arterial tone assessment regardless of the monitor used to measure its determinant.

CLINICAL TRIAL REGISTRATION

DRCIT95.

Journal of Clinical Monitoring and Computing 2017 end of year summary: cardiovascular and hemodynamic monitoring

Hemodynamic monitoring provides the basis for the optimization of cardiovascular dynamics in intensive care medicine and anesthesiology. The Journal of Clinical Monitoring and Computing (JCMC) is an ideal platform to publish research related to hemodynamic monitoring technologies, cardiovascular (patho)physiology, and hemodynamic treatment strategies. In this review, we discuss selected papers published on cardiovascular and hemodynamic monitoring in the JCMC in 2017.

Peripheral Venous Waveform Analysis for Detecting Hemorrhage and Iatrogenic Volume Overload in a Porcine Model

BACKGROUND

Unrecognized hemorrhage and unguided resuscitation is associated with increased perioperative morbidity and mortality. The authors investigated peripheral venous waveform analysis (PIVA) as a method for quantitating hemorrhage as well as iatrogenic fluid overload during resuscitation.

METHODS

The authors conducted a prospective study on Yorkshire Pigs (n = 8) undergoing hemorrhage, autologous blood return, and administration of balanced crystalloid solution beyond euvolemia. Intra-arterial blood pressure, electrocardiogram, and pulse oximetry were applied to each subject. Peripheral venous pressure was measured continuously through an upper extremity standard peripheral IV catheter and analyzed with LabChart. The primary outcome was comparison of change in the first fundamental frequency (f1) of PIVA with standard and invasive monitoring and shock index (SI).

RESULTS

Hemorrhage, return to euvolemia, and iatrogenic fluid overload resulted in significantly non-zero slopes of f1 amplitude. There were no significant differences in heart rate or mean arterial pressure, and a late change in SI. For the detection of hypovolemia the PIVA f1 amplitude change generated an receiver operator curves (ROC) curve with an area under the curve (AUC) of 0.93; heart rate AUC = 0.61; mean arterial pressure AUC = 0.48, and SI AUC = 0.72. For hypervolemia the f1 amplitude generated an ROC curve with an AUC of 0.85, heart rate AUC = 0.62, mean arterial pressure AUC = 0.63, and SI AUC = 0.65.

CONCLUSIONS

In this study, PIVA demonstrated a greater sensitivity for detecting acute hemorrhage, return to euvolemia, and iatrogenic fluid overload compared with standard monitoring and SI. PIVA may provide a low-cost, minimally invasive monitoring solution for monitoring and resuscitating patients with perioperative hemorrhage.

Prediction of Fluid Responsiveness by a Non-invasive Respiratory Systolic Time Interval Variation Using Heart Sound Signals in Recipients Undergoing Liver Transplantation

BACKGROUND

The fluid management of cirrhotic patients undergoing liver transplantation (LT) is challenging. Phonocardiography, a graphic recording of heart sounds, provides valuable information concerning heart function and hemodynamic condition. We assessed whether the systolic time interval (STI) and its respiratory variation could predict fluid responsiveness in cirrhotic patients undergoing LT.

METHODS

Thirty LT recipients who needed volume expansion were included. The fluid challenge consisted of 500 mL 5% albumin administered over a period of 10 minutes. STI was measured as the time interval between the maximal amplitude of each heart sound corrected with the corresponding RR interval (cSTI). The respiratory variation in STI (STV) induced by mechanical ventilation was calculated. Responders were defined as those showing a ≥10% increase in stroke volume index after volume expansion.

RESULTS

In all, 14 of the 30 patients were responders. Significant increases in cSTI were observed after volume expansion in both responders (P < .001) and non-responders (P = .008). Responders showed significant decreases in STV (11.1% ± 4.3% vs 6.1% ± 2.6%, P < .001) after fluid loading, whereas STV in non-responders remained unchanged (6.4% ± 2.6% vs 6.4% ± 4.2%, P = .86). A cut-off value of ≥7.5% STV from baseline could predict fluid responsiveness with an area under the receiver operating characteristic curve of 0.804 (95% confidence interval, 0.618-0.925).

CONCLUSIONS

Intra-operative STV can predict fluid responsiveness in patients undergoing LT. Beat-to-beat monitoring of STI and STV may be useful as a non-invasive hemodynamic index and for fluid management.

Can non-invasive ventilation modify central venous pressure? Comparison between invasive measurement and ultrasonographic evaluation

Central venous pressure (CVP) is primarily measured to assess intravascular volume status and heart preload. In clinical practice, the measuring device most commonly used in emergency departments and intensive care units, is an electronic transducer that interconnects a central venous catheter (CVC) with a monitoring system. Non-invasive ventilation (NIV) consists in a breathing support that supplies a positive pressure in airways through a mask or a cask though not using an endotracheal prosthesis. In emergency settings, non-invasive ultrasonography evaluation of CVP, and hence of intravascular volume status entail the measurement by a subxiphoid approach of inferior vena cava diameter and its variations in relation to respiratory activity. In the literature, there are many studies analyzing the ability to estimate CVP through ultrasonography, rating inspiratory and expiratory vena cava diameters and their ratio, defined as inferior vena cava collapsibility index (IVC-CI). At the same time, the effects of invasive mechanical ventilation on blood volume and the correlation during ventilation between hemodynamic invasive measurement of CVP and inferior vena cava diameters have already been demonstrated. Nevertheless, there are no available data regarding the hemodynamic effects of NIV and the potential correlations during this kind of ventilation between invasive and non-invasive CVP measurements. Therefore, this study aims to understand whether there exists or not an interrelationship between the values of CVP assessed invasively through a CVC and non-invasively through the IVC-CI in patients with severe respiratory distress, and above all to evaluate if these means of assessment can be influenced using NIV.

Assessment of method agreement between two minimally invasive hemodynamic measurements in septic shock patients on high doses of vasopressor drugs. A preliminary study

BACKGROUND

Minimally invasive hemodynamic monitoring is still controversial among the methods used to assess the hemodynamic profile of the septic shock patient. The aim of this study was to test the level of agreement between two different devices.

METHODS

We collected 385 data entries during 12-hour intervals from four critically ill patients with septic shock and high doses of vasoactive therapy using two minimally invasive methods at the same time: Vigileo™ device which uses the pulse contour principle, and EV1000™ monitoring platform which uses the transpulmonary thermodilution principle. The studied parameters were Stroke Volume (SV), Cardiac Output (CO) and Mean Arterial Pressure (MAP). We tested the agreement by performing the visual examination of data patterns using graphs and studying the bias, limits of agreement and creating Bland-Altman plots. For assessing the systematic, proportional and random differences, we computed a Passing-Bablock regression with the CUSUM test for linearity.

RESULTS

The one sample t-Test for the differences between the two methods against the null value was statistically significant for the studied parameters (p < 0.0001). The Bland-Altman analysis found no agreement between the data obtained using the two techniques, with calculated error percent as high as 88.28% for SV, 82.02% for CO and 42.06% for MAP. The Passing-Bablock regression analysis tested positive for systematic differences, but this could not be accounted for.

CONCLUSION

We found no agreement between data obtained from the studied devices; therefore, these cannot be used interchangeably for critically ill septic shock patients on high doses of vasoactive substances.

Accuracy of pleth variability index compared with inferior vena cava diameter to predict fluid responsiveness in mechanically ventilated patients

In the intensive care unit (ICU), stable hemodynamics are very important. Hemodynamic intervention is often effective against multiple organ failure, such as in tissue hypoxia and shock. The administration of intravenous fluids is the first step in regulating tissue perfusion.The main objective of this study is to compare the performance between 2 methods namely pleth variability index (PVI) and IVC distensibily index (dIVC).In this study, the hemodynamic measurements were performed before and after passive leg raising (PLR). Measurements were obtained, including, PVI, dIVC, and cardiac index (CI). Both CI and dIVC measurements were evaluated by transesophageal probe and convex probe respectively. The dIVC measurements were taken using M-mode, 2 cm from junction between the right atrium and the inferior vena cava. The PVI was measured by Masimo Radical-7 monitor, Masimo.A total of 72 patients were included. The dIVC at a threshold value of >23.8% provided 80% sensitivity and 87.5% specificity to predict fluid responsiveness and was statistically significant (P < .001), with an AUC 0.928 (0.842-0.975). The PVI at a threshold value of >14% provided 95% sensitivity and 81.2% specificity to predict fluid responsiveness and was statistically significant (P < .001), with an AUC 0.939 (0.857-0.982).Both PVI and dIVC can be used as a noninvasive method that can be easily applied at the bedside in determining fluid responsiveness in all patients with mechanical ventilation in intensive care.

Use of a Minimally Invasive Cardiac Output Monitor to Optimise Haemodynamics in a Patient with Mitral Valve Disease Undergoing Cerebrovascular Surgery

Patients with mitral valve disease undergoing cerebrovascular surgery face increased inherent risks due to their associated cardiac comorbidities. As such, the anaesthetic management of such patients is distinctly challenging. Simultaneous consideration of both the cerebrovascular and underlying cardiac conditions determines key anaesthetic issues, as fluids and vasopressors or inotropes need to be titrated according to haemodynamic variables in order to optimise cerebral blood flow without compromising cardiac function. We report a 45-year-old female patient with mild mitral stenosis and moderate-to-severe mitral regurgitation who presented to the Khoula Hospital, Muscat, Oman, in 2016 following a ruptured anterior communicating artery aneurysm requiring urgent surgical intervention. As highlighted in this case, the VolumeView EV1000™ (Edwards Lifesciences, Irvine, California, USA) system is a minimially invasive haemodynamic monitor that can help immensely in the perioperative management of such patients.

Evaluation of the use of the fourth version FloTrac system in cardiac output measurement before and after cardiopulmonary bypass

The FloTrac system is a system for cardiac output (CO) measurement that is less invasive than the pulmonary artery catheter (PAC). The purposes of this study were to (1) compare the level of agreement and trending abilities of CO values measured using the fourth version of the FloTrac system (CCO-FloTrac) and PAC-originated continuous thermodilution (CCO-PAC) and (2) analyze the inadequate CO-discriminating ability of the FloTrac system before and after cardiopulmonary bypass (CPB). Fifty patients were included. After exclusion, 32 patients undergoing cardiac surgery with CPB were analyzed. All patients were monitored with a PAC and radial artery catheter connected to the FloTrac system. CO was assessed at 10 timing points during the surgery. In the Bland-Altman analysis, the percentage errors (bias, the limits of agreement) of the CCO-FloTrac were 61.82% (0.16, - 2.15 to 2.47 L min) and 51.80% (0.48, - 1.97 to 2.94 L min) before and after CPB, respectively, compared with CCO-PAC. The concordance rates in the four-quadrant plot were 64.10 and 62.16% and the angular concordance rates (angular mean bias, the radial limits of agreement) in the polar-plot analysis were 30.00% (17.62°, - 70.69° to 105.93°) and 38.63% (- 10.04°, - 96.73° to 76.30°) before and after CPB, respectively. The area under the receiver operating characteristic curve for CCO-FloTrac was 0.56, 0.52, 0.52, and 0.72 for all, ≥ ± 5, ≥ ± 10, and ≥ ± 15% CO changes (ΔCO) of CCO-PAC before CPB, respectively, and 0.59, 0.55, 0.49, and 0.46 for all, ≥ ± 5, ≥ ± 10, and ≥ ± 15% ΔCO of CCO-PAC after CPB, respectively. When CO < 4 L/min was considered inadequate, the Cohen κ coefficient was 0.355 and 0.373 before and after CPB, respectively. The accuracy, trending ability, and inadequate CO-discriminating ability of the fourth version of the FloTrac system in CO monitoring are not statistically acceptable in cardiac surgery.