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The central venous catheter is a common piece of equipment utilized in anaesthesia and intensive care medicine. Whilst traditionally, measurement of central venous pressure was used as an indicator of fluid responsiveness, the two have been shown not to correlate well. Pulmonary artery catheters, on the other hand, can be used to diagnose and classify shock. However, its many drawbacks have led to it falling out of favour outside of high-risk cardiac perioperative care. [ABSTRACT FROM AUTHOR]

Abstract Background Cardiac output (CO) is a key measure of adequacy of organ and tissue perfusion, especially in critically ill or complex surgical patients. CO monitoring technology continues to evolve. Recently developed CO monitors rely on unique algorithms based on pulse contour analysis of an arterial blood pressure (ABP) waveform. The objective of this investigation was to compare the accuracy of two monitors using different methods of pulse contour analysis – the Retia Argos device and the Edwards Vigileo-FloTrac device – with pulmonary artery catheter (PAC)-thermodilution as a reference. Methods Fifty-eight patients undergoing off-pump coronary artery bypass surgery formed the study cohort. A total of 572 triplets of CO measurements from each device – Argos, Vigileo-FloTrac (third generation), and thermodilution – were available before and after interventions (e.g., vasopressors, fluids, and inotropes). Bland–Altman analysis accounting for repeated measurements per subject and concordance analysis were applied to assess the accuracy of the CO values and intervention-induced CO changes of each pulse contour device against thermodilution. Cluster bootstrapping was employed to statistically compare the root-mean-squared-errors (RMSE = √(μ2 + σ2), where μ and σ are the Bland–Altman bias and precision errors) and concordance rates of the two devices. Results The RMSE (mean (95% confidence intervals)) for CO values was 1.16 (1.00–1.32) L/min for the Argos device and 1.54 (1.33–1.77) L/min for the Vigileo-FloTrac device; the concordance rate for intervention-induced CO changes was 87 (82–92)% for the Argos device and 72 (65–78)% for the Vigileo-FloTrac device; and the RMSE for the CO changes was 17 (15–19)% for the Argos device and 21 (19–23)% for the Vigileo-FloTrac device (p

Multi-beat analysis (MBA) of the radial arterial pressure (AP) waveform is a new method that may improve cardiac output (CO) estimation via modelling of the confounding arterial wave reflection. We evaluated the precision and accuracy using the trending ability of the MBA method to estimate absolute CO and variations (ΔCO) during hemodynamic challenges. We reviewed the hemodynamic challenges (fluid challenge or vasopressors) performed when intra-operative hypotension occurred during non-cardiac surgery. The CO was calculated offline using transesophageal Doppler (TED) waveform (COTED) or via application of the MBA algorithm onto the AP waveform (COMBA) before and after hemodynamic challenges. We evaluated the precision and the accuracy according to the Bland & Altman method. We also assessed the trending ability of the MBA by evaluating the percentage of concordance with 15% exclusion zone between ΔCOMBA and ΔCOTED. A non-inferiority margin was set at 87.5%. Among the 58 patients included, 23 (40%) received at least 1 fluid challenge, and 46 (81%) received at least 1 bolus of vasopressors. Before treatment, the COTED was 5.3 (IQR [4.1–8.1]) l min−1, and the COMBA was 4.1 (IQR [3–5.4]) l min−1. The agreement between COTED and COMBA was poor with a 70% percentage error. The bias and lower and upper limits of agreement between COTED and COMBA were 0.9 (CI95 = 0.82 to 1.07) l min−1, −2.8 (CI95 = −2.71 to−2.96) l min−1 and 4.7 (CI95 = 4.61 to 4.86) l min−1, respectively. After hemodynamic challenge, the percentage of concordance (PC) with 15% exclusion zone for ΔCO was 93 (CI97.5 = 90 to 97)%. In this retrospective offline analysis, the accuracy, limits of agreements and percentage error between TED and MBA for the absolute estimation of CO were poor, but the MBA could adequately track induced CO variations measured by TED. The MBA needs further evaluation in prospective studies to confirm those results in clinical practice conditions. [ABSTRACT FROM AUTHOR]

Thermodilution cardiac output monitoring, using a thermistor-tipped intravascular catheter, is used in critically ill patients to guide hemodynamic therapy. Often, these patients also need magnetic resonance imaging (MRI) for diagnostic or prognostic reasons. As thermodilution catheters contain metal, they are considered MRI-unsafe and advised to be removed prior to investigation. However, removal and replacement of the catheter carries risks of bleeding, perforation and infection. This research is an in vitro safety assessment of the PiCCO™ thermodilution catheter during 3 T Magnetic Resonance Imaging (3T-MRI). In a 3T-MRI environment, three different PiCCO™ catheter sizes were investigated in an agarose-gel, tissue mimicking phantom. Two temperature probes measured radiofrequency-induced heating; one at the catheter tip and one at a reference point. Magnetically induced catheter dislocation was assessed by visual observation as well as by analysis of the tomographic images. For all tested catheters, the highest measured temperature increase was 0.2 °C at the center of the bore and 0.3 °C under "worst-case" setting for the tested MRI pulse sequences. No magnetically induced catheter displacements were observed. Under the tested circumstances, no heating or dislocation of the PiCCO™ catheter was observed in a tissue mimicking phantom during 3T-MRI. Leaving the catheter in the critically ill patient during MRI investigation might pose a lower risk of complications than catheter removal and replacement. [ABSTRACT FROM AUTHOR]

Background: Studies have shown that cardiac output-guided hemodynamic therapy reduces complications and length of hospital stay in the postoperative period. However, this strategy has variable effects in cardiac surgical patients at risk for low-cardiac-output syndrome (LCOS). Objective: To compare the overall 30-day composite endpoint and hospital stay between conventional treatment (Group A) and cardiac outputguided hemodynamic therapy by institutional protocol (Group B) in postoperative cardiac surgical patients at risk for LCOS. Materials and Methods: Sixty-five patients with 35 in Group A and 30 in Group B, that underwent coronary artery bypass surgery or valvular heart surgery between August 2018 and July 2019 were prospectively analyzed. In Group A, patients received standard protocol treatment guided primarily by mean arterial pressure and central venous pressure in the intensive care unit (ICU). In Group B, patients received treatment guided primarily by stroke volume variation, mean arterial pressure, and the cardiac index using the FloTrac monitoring system. Results: The overall 30-day composite Group A and Group B endpoints were 62.9% and 46.7% (p=0.145), respectively. Group B had a lower occurrence of LCOS at 30% versus 37.1% (p=0.366), postoperative kidney injury at 20% versus 28.6% (p=0.424), and postoperative arrythmia at 20% versus 40% (p=0.082). Postoperative hemodialysis and postoperative mortality were higher in Group A at 5.7% versus 0% (p=0.184), and 2.9% versus 0% (p=0.351), respectively). Comparing both groups, there was no difference in length of ICU stay at 4 [3 to 5] versus 4 (2 to 5), (p=0.577) and hospital stay at 10 (9 to 130 versus 10 (9 to 11)(, p=0.201). Conclusion: After cardiac surgery, cardiac output-guided hemodynamic therapy, compared to conventional treatment, insignificantly reduced the 30-day composite endpoint and length of hospital stay. [ABSTRACT FROM AUTHOR]

Over 300 million surgical procedures are performed every year worldwide. Anesthesiologists play an important role in the perioperative process by assessing the overall risk of surgery and aim to reduce the risk of complications. Perioperative hemodynamic and volume management can help to improve outcomes in perioperative patients. There has been ongoing discussion about goal-directed therapy. However, there is a consensus that fluid overload and severe fluid depletion in the perioperative period are harmful and can lead to adverse outcomes. This article provides an overview of how to evaluate the fluid responsiveness of patients, details which parameters could be used, and what limitations should be noted.

Introduction: Patients undergoing cardiovascular surgery may experience hemodynamic instability during the induction of general anesthesia, and anesthetic agents with minimal hemodynamic effects should be administered. Midazolam, a classic benzodiazepine anesthetic, is known to have relatively weak circulatory depression during anesthesia induction compared to other sedatives. On the other hand, remimazolam, a newly approved short-acting benzodiazepine anesthetic, is expected to have fewer circulatory depressant effects. However, comparisons between remimazolam and midazolam regarding circulatory depression during anesthesia induction have not been adequately studied., Objective: This study aims to compare the hemodynamic effects of remimazolam and midazolam during anesthesia induction in patients undergoing cardiovascular surgery., Method: In this single-center retrospective and exploratory study, adults undergoing cardiovascular surgery under general anesthesia were divided into the remimazolam group (R group) and midazolam group (M group). Remimazolam 0.06 mg/kg (R group) or midazolam 0.03 mg/kg (M group) was administered during induction of general anesthesia. Both groups received remifentanil 1 μg/kg/min as analgesia. During anesthesia induction, additional sedatives (remimazolam or midazolam, respectively) were administered as needed to maintain the bispectral index (BIS) below 60. The primary endpoints were the following hemodynamic parameters: mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI), and stroke volume variation (SVV). Measurements were taken before the induction of anesthesia, one and three minutes after rocuronium administration, and one, three, five, and 10 minutes after tracheal intubation. Secondary endpoints included the number of patients requiring vasopressors and vasopressor dosage, time to fall asleep, and BIS values. All values are expressed as the median (interquartile range). Continuous variables were compared using the Mann-Whitney U test. Statistically significant differences were set at p-values <0.05., Results: Forty patients (20 in each group) were included in the final analysis. The doses of remimazolam and midazolam until sleep onset were 0.058 (0.053, 0.066) mg/kg in the R group and 0.035 (0.03, 0.045) mg/kg in the M group. The MAP at five minutes and 10 minutes after tracheal intubation was significantly higher in the R group than in the M group (p=0.031 and p=0.004, respectively). The HR, CI, SVI, SVRI, and SVV were not significantly different between the two groups at any of the measurement points. The number of patients requiring vasopressors and vasopressor dosage were not statistically significant between the two groups. The time to fall asleep was 124 seconds (90, 142) in the R group and 146 seconds (130, 167) in the M group, with a significant difference (p=0.01). The BIS values during anesthesia induction were not significantly different between the two groups., Conclusion: Remimazolam had fewer hemodynamic effects than midazolam, even with relatively high doses and an earlier sleep onset. In terms of hemodynamic stability, remimazolam may be beneficial during anesthetic induction; however, further research is needed to confirm its efficacy., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Institutional Review Board of Sasebo City General Hospital issued approval 2021-A027. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Shintani et al.)

The management of the circulation in critically ill patients presents significant challenges. Shock is a potentially reversible life-threatening physiological state characterized by end-organ dysfunction due to an imbalance in oxygen delivery (DO 2) and tissue demand (VO 2). Independent of its aetiology, untreated shock precipitates a cascade of pro-inflammatory mediators resulting in cellular damage and end-organ dysfunction. Thus it is the duty of all clinicians to promptly recognize, diagnose and initiate treatments to halt this process. Despite optimum management, shock can progress to multi-organ failure necessitating critical care admission and advanced haemodynamic management. This article will classify shock syndromes, discuss the principles of diagnosis, use of haemodynamic monitoring and management strategies for circulatory failure in the critically ill patient. [ABSTRACT FROM AUTHOR]

Objective:Our study aimed to assess the correlation between the measured PiCCO® parameters and extubation time and intensive care unit (ICU) length of stay in patients who underwent coronary artery bypass grafting (CABG) surgery and were managed by monitorization of cardiac output and cardiac performance parameters with PiCCO®.Method:This study was conducted by retrospective analysis data of all 44 patients who underwent CABG surgery during December 2015-March 2016 and were managed through PiCCO® monitorization. The patients’ demographic characteristics (age, sex, weight, height, body mass index), American Society of Anesthesiologists physical conditions, comorbidities, ejection fractions, anesthetic management, operative details, hemodynamic data, PiCCO® parameters, extubation times, cardiovascular surgery ICU lengths of stay, requirements for vasoactive agent and blood transfusion, mortality, and morbidity were recorded from patient records and evaluated the correlation between the measured PiCCO® parameters and extubation time and ICU length of stay inpatients.Results:A significant increase was detected in the parameters of cardiac contractility and performance monitored with PiCCO® in the postoperative period (p

The accurate quantification of cardiac output (CO) is given vital importance in modern medical practice, especially in high-risk surgical and critically ill patients. CO monitoring together with perioperative protocols to guide intravenous fluid therapy and inotropic support with the aim of improving CO and oxygen delivery has shown to improve perioperative outcomes in high-risk surgical patients. Understanding of the underlying principles of CO measuring devices helps in knowing the limitations of their use and allows more effective and safer utilization. At present, no single CO monitoring device can meet all the clinical requirements considering the limitations of diverse CO monitoring techniques. The evidence for the minimally invasive CO monitoring is conflicting; however, different CO monitoring devices may be used during the clinical course of patients as an integrated approach based on their invasiveness and the need for additional hemodynamic data. These devices add numerical trend information for anesthesiologists and intensivists to use in determining the most appropriate management of their patients and at present, do not completely prohibit but do increasingly limit the use of the pulmonary artery catheter.

Abstract Background Despite the evidence for calibrated cardiac monitored devices to determine fluid responsiveness, there is minimal evidence that the use of cardiac output monitor devices leads to an overall change in IV fluid use. We sought to investigate the feasibility of performing a randomised controlled study using calibrated cardiac output monitoring devices in shocked ICU patients and whether the use of these devices led to a difference in total volume of IV fluid administered. Methods We performed a single-centre non-blinded randomised controlled study which included patients who met the clinical criteria for shock on admission to ICU. Patients were divided into two groups (cardiac output monitors or standard) by block randomisation. Patients allocated to the cardiac output monitor all received EV1000 with Volume View sets. Daily intravenous fluid administration and cumulative fluid balance was recorded for 3 days. The primary outcome assessed was the difference in daily intravenous fluid administration and cumulative fluid balance at 72 h between the two groups. We also assessed how often the clinicians used the cardiac monitor to guide fluid therapy and the different reasoning for initiating further intravenous fluids. Results Eighty patients were randomised and 37 received calibrated cardiac output monitors. We found no adverse outcomes in the use of calibrated cardiac output monitoring devices and that was feasible to perform a randomised controlled trial. There was no significant difference between the standard care group vs the cardiac monitoring group for cumulative fluid balance (2503 ± 3764 ml vs 2458 ± 3560 ml, p = 0.96). There was no significant difference between the groups for daily intravenous fluid administration on days 1, 2 or 3. In the cardiac monitored group, only 43% of the time was the EV1000 output incorporated into the decision to give further intravenous fluids. Conclusion It is feasible to perform a randomised controlled trial using calibrated cardiac output monitoring devices. In addition, there was no trend to suggest that the use of a cardiac monitors leads to lower IV fluid use in the shocked patient. Further trials will require study designs to optimise the use of a cardiac output monitor to determine the utility of these devices in the shocked patient. Trial registration ANZCTR, ACTRN12618001373268. Registered 15 August 2018—retrospectively registered.

Over 300 million surgical procedures are performed every year worldwide. Anesthesiologists play an important role in the perioperative process by assessing the overall risk of surgery and aim to reduce the risk of complications. Perioperative hemodynamic and volume management can help to improve outcomes in perioperative patients. There has been ongoing discussion about goal-directed therapy. However, there is a consensus that fluid overload and severe fluid depletion in the perioperative period are harmful and can lead to adverse outcomes. This article provides an overview of how to evaluate the fluid responsiveness of patients, details which parameters could be used, and what limitations should be noted. [ABSTRACT FROM AUTHOR]

Abstract Background Cardiac output (CO) monitoring is a valuable tool for the diagnosis and management of critically ill patients. In the critical care setting, few studies have evaluated the level of agreement between CO estimated by transthoracic echocardiography (CO-TTE) and that measured by the reference method, pulmonary artery catheter (CO-PAC). The objective of the present study was to evaluate the precision and accuracy of CO-TTE relative to CO-PAC and the ability of transthoracic echocardiography to track variations in CO, in critically ill mechanically ventilated patients. Methods Thirty-eight mechanically ventilated patients fitted with a PAC were included in a prospective observational study performed in a 16-bed university hospital ICU. CO-PAC was measured via intermittent thermodilution. Simultaneously, a second investigator used standard-view TTE to estimate CO-TTE as the product of stroke volume and the heart rate obtained during the measurement of the subaortic velocity time integral. Results Sixty-four pairs of CO-PAC and CO-TTE measurements were compared. The two measurements were significantly correlated (r = 0.95; p

Transpulmonary thermodilution devices have been widely shown to be accurate in septic shock patients in assessing fluid responsiveness. We conducted a systematic review to assess the relationship between fluid therapy protocols guided by transpulmonary thermodilution devices on fluid balance and the amount of intravenous fluid used in septic shock. We searched MEDLINE, Embase and The Cochrane Library. Studies were eligible for inclusion if they were prospective, parallel trials that were conducted in an intensive care setting in patients with septic shock. The comparator group was either central venous pressure, early goal-directed therapy or pulmonary artery occlusion pressure. Studies assessing only the accuracy of fluid responsiveness prediction by transpulmonary thermodilution devices were excluded. Two reviewers independently performed the search, extracted data and assessed the bias of each study. In total 27 full-text articles were identified for eligibility; of these, nine studies were identified for inclusion in the systematic review. Three of these trials used dynamic parameters derived from transpulmonary thermodilution devices and six used primarily static parameters to guide fluid therapy. There was evidence for a significant reduction in positive fluid balance in four out of the nine studies. From the available studies, the results suggest the benefit of transpulmonary thermodilution monitoring in the septic shock population with regard to reducing positive fluid balance is seen when the devices are utilised for at least 72 hours. Both dynamic and static parameters derived from transpulmonary thermodilution devices appear to lead to a reduction in positive fluid balance in septic shock patients compared to measurements of central venous pressure and early goal-directed therapy. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the effects of using a real time clinical decision-support system, "Assisted Fluid Management" (AFM), to guide goal-directed fluid therapy (GDFT) during major abdominal surgery. We compared a group of patients managed using the AFM system with a historical cohort of patients (control group) who had been managed using a manual GDFT strategy. Adherence to the protocol was defined as the relative intraoperative time spent with a stroke volume variation (SVV) < 13%. We hypothesised that patients in the AFM group would have more time during surgery with a SVV < 13% compared to the control group. All patients had a radial arterial line connected to a pulse contour analysis monitor and received a 2 ml/kg/h maintenance crystalloid infusion. Additional 250 ml crystalloid boluses were administered whenever measured SVV ≥ 13% in the control group, and when the software suggested a fluid bolus in the AFM group. We compared 46 AFM-guided patients to 38 controls. Patients in the AFM group spent significantly more time during surgery with a SVV < 13% compared to the control group (median 92% [82, 96] vs. 76% [54, 86]; P < 0.0005), and received less fluid overall (1775 ml [1225, 2425] vs. 2350 ml [1825, 3250]; P = 0.010). The incidence of postoperative complications was comparable in the two groups. Implementation of a decision support system for GDFT guidance resulted in a significantly longer period during surgery with a SVV < 13% with a reduced total amount of fluid administered. Trial registration: Clinical Trials.gov (NCT03141411). [ABSTRACT FROM AUTHOR]

Introduction: Cocaine toxicity is a clinical condition that includes acute toxicity and/or chronic complications affecting multiple organs and may require intensive care support. Cardiac output (CO) monitoring may be benefical for the management of critically ill patients with cocain toxicity. Case: A 26-year-old male patient was admitted to the intensive care unit (ICU) with hyperlactatemia and agitation. On ICU admission, his APACHE II score was 15, SOFA score 2, and GCS 15. Acidemia persisted despite supportive care, including intravenous fluids, sodium bicarbonate, antibiotics, vasopressors, and inotropes. The patient was intubated because of severe agitation and pulmonary edema. Transpulmonary thermodilution (PiCCO® ) was used in addition to echocardiography (ECHO) to determine the type of severe shock as the patient did not respond the initial therapy. Monitoring findings included decreased global end diastolic volume, cardiac output, systemic vascular resistance index, global ejection fraction, increased pulmonary vascular permeabilty index and extravascular lung water index. ECHO revealed an impaired cardiac contractility. He had distributive, cardiogenic and hypovolemic shock. Therefore, we had to give 36 liters of fluid intravenously (IV) over 24 hours and high-dose vasopressor and inotropic therapies were applied. Methylene blue was used for refractory vasoplegia and IV lipid solution was administered beaouse of history of cocaine usage. Continuous venovenous hemodiafiltration (CVVHDF) with a cytokine-removal filter was performed due to stage II acute kidney injury. He was weaned from the mechanical ventilator and CVVHDF on 4th day of ICU admission and was discharged from the hospital on the 11th day of hospital admission. Discussion: Illicit drug usage and cocaine toxicity should be kept in mind if the presence of severe shock and hyperlactatemia of unknown cause. CO monitoring may play a central role in the rapid treatment and management of drug-induced toxicity and severe shock. [ABSTRACT FROM AUTHOR]

Introduction: Transpulmonary thermodilution (TPTD) devices may be useful in critically ill complex patients with severe shock. We presented our experiences among different types of critically ill patients with shock to optimise fluid resuscitation and vasopressor therapy with a cardiac output (CO) monitoring. Case: Case 1A 53-year-old female who underwent laparotomy due to hemorrhagic shock after gunshot wound. TPTD was needed as the patient did not respond to initial therapy. Continuous renal replacement therapy (CRRT) was started due to acute kidney injury (AKI) stage 2. Patient died because of acute liver failure at the 12th day of ICU admission. Case 2A 26-year-old male was admitted to the ICU with hyperlactatemia and cyanosis. With a pre-diagnosis of cocaine toxicity due to his history of misuse. In line with the TPTD, we had to give 36 liters of fluid in 24 hours. He was weaned from the mechanical ventilator, CRRT on his 4th day in the ICU and discharged from the hospital on the 11th day. Case 3A 60-year-old male who had DM, HT, and cardiac failure was admitted to the ICU with severe ARDS and septic shock. TPTD was used to monitor preload and fluid responsiveness. Monitoring findings included ELWI: 36 mL/kg and PVPI: 6.9. CRRT was started for both stage II AKI and ultrafiltration. He was weaned from CRRT on the 10th day of ICU admission. He was discharged from ICU on the 31st day. Case 4A 28-year-old female with 50% TBSA (3rd degree) flame burn injury was admitted to the ICU. TPTD was performed to monitor cardiac function due to circulatory shock unresponsive to initial therapeutic interventions. She was discharged from hospital 4 months later. Discussion: Our experience indicates that among complex critically ill shock patients, use of TPTD provides monitoring cardiac output and hemodynamics to identify the type of shock and select the therepautic intervention. [ABSTRACT FROM AUTHOR]

The accurate quantification of cardiac output (CO) is given vital importance in modern medical practice, especially in high-risk surgical and critically ill patients. CO monitoring together with perioperative protocols to guide intravenous fluid therapy and inotropic support with the aim of improving CO and oxygen delivery has shown to improve perioperative outcomes in high-risk surgical patients. Understanding of the underlying principles of CO measuring devices helps in knowing the limitations of their use and allows more effective and safer utilization. At present, no single CO monitoring device can meet all the clinical requirements considering the limitations of diverse CO monitoring techniques. The evidence for the minimally invasive CO monitoring is conflicting; however, different CO monitoring devices may be used during the clinical course of patients as an integrated approach based on their invasiveness and the need for additional hemodynamic data. These devices add numerical trend information for anesthesiologists and intensivists to use in determining the most appropriate management of their patients and at present, do not completely prohibit but do increasingly limit the use of the pulmonary artery catheter. [ABSTRACT FROM AUTHOR]

Abstract The management of the circulation in critically ill patients presents significant challenges. Shock is a potentially reversible life-threatening physiological state characterized by end-organ dysfunction due to an imbalance in oxygen delivery (DO 2) and tissue demand (VO 2). Independent of its aetiology, untreated shock precipitates a cascade of pro-inflammatory mediators resulting in cellular damage and end-organ dysfunction. Thus it is the duty of all clinicians to promptly recognize, diagnose and initiate treatments to halt this process. Despite optimum management, shock can progress to multi-organ failure necessitating critical care admission and advanced haemodynamic management. This article will classify shock syndromes, discuss the principles of diagnosis, use of haemodynamic monitoring and management strategies for circulatory failure in the critically ill patient. [ABSTRACT FROM AUTHOR]

Technologies for minimally-invasive cardiac output measurement in patients during surgery remain little used in routine practice. We tested a redeveloped system based on CO2 elimination (VCO2) by the lungs for use in ventilated patients, which can be seamlessly integrated into a modern anesthesia/monitoring platform, and provides automated, continuous breath-by-breath cardiac output monitoring. A prototype measurement system was constructed to measure VCO2 and end-tidal CO2 concentration with each breath. A baseline measurement of non-shunt cardiac output was made during a brief oscillating change in ventilator rate, according to the differential CO2 Fick approach and repeated at 5-10 min intervals. Continuous breath-by-breath monitoring of cardiac output was performed between these intervals from measurement of VCO2, using a derivation of the Fick equation applied to pulmonary CO2 elimination and cardiac output displayed in real time. Measurements were compared with simultaneous measurements by thermodilution in 50 patients undergoing cardiac surgery or liver transplantation. Overall mean bias [sd] for agreement in cardiac output measurement was - 0.3 [1.1] L/min, percentage error ± 38.7%, intraclass correlation coefficient = 0.91. Concordance in measurement of changes of at least 15% in cardiac output was 81.4%, with a mean angular bias of - 1.7°, and radial limits of agreement of ± 76.2° on polar plot analysis. The accuracy and precision compared favourably to other clinical techniques. The method is relatively seamless and automated and has potential for continuous, cardiac output monitoring in ventilated patients during anesthesia and critical care. [ABSTRACT FROM AUTHOR]

Purpose:Hyperthermic intra-thoracic chemotherapy (HITOC) combined with cytoreductive surgery (CRS) is a novel approach in the management of pseuodmyxoma peritonei with thoracic extension. The haemodynamic effects of hyperthermic chemotherapy present an anaesthetic challenge. Here, we describe the haemodynamic changes seen during HITOC. Materials and methods:A retrospective case note review of adult patients undergoing CRS with HITOC from 2009 to 2016. Intra-operative haemodynamics were measured using the LIDCOrapidTMbrand of invasive cardiac output (CO) monitor. Intravenous fluids, vasopressor requirements and urine output (UO) were recorded. Results:Four patients were included in the study. Mean heart rate (HR) peaked at 20 min following commencement of HITOC. The difference between HR at time 0 and at peak was minimal. There was minimal change in CO, and stroke volume variation (SVV) remained stable. Vasopressor dose was minimally changed throughout surgery. Average UO during HITOC was 142.5 ± 109.6 mls at 60 min. Mean fluid requirements during HITOC was 586.2 ± 441.2 mls. No significant change occurred in pH or base excess (BE). Conclusions:Significant haemodynamic instability including cardiac asystole has been reported during HITOC. The application of hyperthermic agents to the thorax results in vasodilatation, cardiac warming and compression of mediastinal vessels. Measurement of haemodynamic variables allowed careful titration of intravenous fluid therapy to CO and stroke volume, allowing for haemodynamic stability. This has not been described elsewhere. [ABSTRACT FROM PUBLISHER]

Background: Cardiac output (CO) monitoring is a valuable tool for the diagnosis and management of critically ill patients. In the critical care setting, few studies have evaluated the level of agreement between CO estimated by transthoracic echocardiography (CO-TTE) and that measured by the reference method, pulmonary artery catheter (CO-PAC). The objective of the present study was to evaluate the precision and accuracy of CO-TTE relative to CO-PAC and the ability of transthoracic echocardiography to track variations in CO, in critically ill mechanically ventilated patients.Methods: Thirty-eight mechanically ventilated patients fitted with a PAC were included in a prospective observational study performed in a 16-bed university hospital ICU. CO-PAC was measured via intermittent thermodilution. Simultaneously, a second investigator used standard-view TTE to estimate CO-TTE as the product of stroke volume and the heart rate obtained during the measurement of the subaortic velocity time integral.Results: Sixty-four pairs of CO-PAC and CO-TTE measurements were compared. The two measurements were significantly correlated (r = 0.95; p < 0.0001). The median bias was 0.2 L/min, the limits of agreement (LOAs) were -1.3 and 1.8 L/min, and the percentage error was 25%. The precision was 8% for CO-PAC and 9% for CO-TTE. Twenty-six pairs of ΔCO measurements were compared. There was a significant correlation between ΔCO-PAC and ΔCO-TTE (r = 0.92; p < 0.0001). The median bias was -0.1 L/min and the LOAs were -1.3 and +1.2 L/min. With a 15% exclusion zone, the four-quadrant plot had a concordance rate of 94%. With a 0.5 L/min exclusion zone, the polar plot had a mean polar angle of 1.0° and a percentage error LOAs of -26.8 to 28.8°. The concordance rate was 100% between 30 and -30°. When using CO-TTE to detect an increase in ΔCO-PAC of more than 10%, the area under the receiving operating characteristic curve (95% CI) was 0.82 (0.62-0.94) (p < 0.001). A ΔCO-TTE of more than 8% yielded a sensitivity of 88% and specificity of 66% for detecting a ΔCO-PAC of more than 10%.Conclusion: In critically ill mechanically ventilated patients, CO-TTE is an accurate and precise method for estimating CO. Furthermore, CO-TTE can accurately track variations in CO. [ABSTRACT FROM AUTHOR]

Studies in the early 2000s suggested that the introduction of flow or cardiac output monitoring could improve outcome in major surgery, especially in high-risk patients. This led the National Institute of Health and Care Excellence (NICE) in the UK to issue guidance in 2011 recommending the use of the Deltex Cardio Q Doppler flow monitor in these patients both to improve outcome and also reduce costs. This advice was subsequently extended to include all "flow monitors" in 2012. However, recent systematic reviews and major randomized controlled trials have failed to confirm the benefits of adding "flow" to conventional monitoring in the perioperative period. This paper examines physiological and methodological reasons behind this failure and introduces an alternative management strategy in high risk patients which incorporates cardiac output monitoring alongside the additional monitoring of cortical suppression and cerebral and tissue oxygenation. [ABSTRACT FROM AUTHOR]

Background: Passive leg raising (PLR) is a so called self-volume challenge used to test for fluid responsiveness. Changes in cardiac output (CO) or stroke volume (SV) measured during PLR are used to predict the need for subsequent fluid loading. This requires a device that can measure CO changes rapidly. The Vigileo™ monitor, using third-generation software, allows continuous CO monitoring. The aim of this study was to compare changes in CO (measured with the Vigileo device) during a PLR manoeuvre to calculate the accuracy for predicting fluid responsiveness. Methods: This is a prospective study in a 20-bedded mixed general critical care unit in a large non-university regional referral hospital. Fluid responders were defined as having an increase in CO of greater than 15 % following a fluid challenge. Patients meeting the criteria for circulatory shock with a Vigileo™ monitor (Vigileo™; FloTrac; Edwards™; Lifesciences, Irvine, CA, USA) already in situ, and assessed as requiring volume expansion by the clinical team based on clinical criteria, were included. All patients underwent a PLR manoeuvre followed by a fluid challenge. Results: Data was collected and analysed on stroke volume variation (SVV) at baseline and CO and SVV changes during the PLR manoeuvre and following a subsequent fluid challenge in 33 patients. The majority had septic shock. Patient characteristics, baseline haemodynamic variables and baseline vasoactive infusion requirements were similar between fluid responders (10 patients) and non-responders (23 patients). Peak increase in CO occurred within 120 s during the PLR in all cases. Using an optimal cut point of 9 % increase in CO during the PLR produced an area under the receiver operating characteristic curve of 0.85 (95 % CI 0.63 to 1.00) with a sensitivity of 80 % (95 % CI 44 to 96 %) and a specificity of 91 % (95 % CI 70 to 98 %). Conclusions: CO changes measured by the Vigileo™ monitor using third-generation software during a PLR test predict fluid responsiveness in mixed medical and surgical patients with vasopressor-dependent circulatory shock. [ABSTRACT FROM AUTHOR]

There is lack of data about the agreement of minimally invasive cardiac output monitors, which make it impossible to determine if they are interchangeable or differ objectively in tracking physiological trends. We studied three commonly used devices: the oesophageal Doppler and two arterial pressure-based devices, the Vigileo FloTrac™ and LiDCOrapid™. The aim of this study was to compare the agreement of these three monitors in adult patients undergoing elective non-cardiac surgery. Measurements were taken at baseline and after predefined clinical interventions of fluid, metaraminol or ephedrine bolus. From 24 patients, 131 events, averaging 5.2 events per patient, were analysed. The cardiac index of LiDCOrapid versus FloTrac had a mean bias of -6.0% (limits of agreement from -51% to 39%) and concordance of over 80% to the three clinical interventions. The cardiac index of Doppler versus LiDCOrapid and Doppler versus FloTrac, had an increasing negative bias at higher mean cardiac outputs and there was significantly poorer concordance to all interventions. Of the preload-responsive parameters, Doppler stroke volume index, Doppler systolic flow time and FloTrac stroke volume variation were fair at predicting fluid responsiveness while other parameters were poor. While there is reasonable agreement between the two arterial pressure-derived cardiac output devices (LiDCOrapid and Vigileo FloTrac), these two devices differ significantly to the oesophageal Doppler technology in response to common clinical intraoperative interventions, representing a limitation to how interchangeable these technologies are in measuring cardiac output. [ABSTRACT FROM AUTHOR]

Abstract Hypovolaemia is defined as inadequate filling of the circulation and can be divided into absolute and relative hypovolaemia. The total body water accounts for 60% of a patient's body composition and is subdivided into extracellular and intracellular fluid compartments. The critical loss appears to be about 30% of the blood volume (1500–2000 ml). In order to limit the physiological effects of hypovolaemia, there are changes within the cardiovascular, renal and haematological systems to help minimize ongoing losses. The history and physical examination may give an indication that a patient is hypovolaemic. However, clinical signs may be a late manifestation of hypovolaemia as up to 15% of the blood volume can be lost before signs and symptoms are evident. It is of vital importance to measure fluid responsiveness in hypovolaemic patients to ensure patients are adequately resuscitated. [ABSTRACT FROM AUTHOR]