Processed electroencephalography-guided general anesthesia and norepinephrine requirements: A randomized trial in patients having vascular surgery.

STUDY OBJECTIVE: Processed electroencephalography (pEEG) may help clinicians optimize depth of general anesthesia. Avoiding excessive depth of anesthesia may reduce intraoperative hypotension and the need for vasopressors. We tested the hypothesis that pEEG-guided - compared to non-pEEG-guided - general anesthesia reduces the amount of norepinephrine needed to keep intraoperative mean arterial pressure above 65 mmHg in patients having vascular surgery. DESIGN: Randomized controlled clinical trial. SETTING: University Medical Center Hamburg-Eppendorf, Hamburg, Germany. PATIENTS: 110 patients having vascular surgery. INTERVENTIONS: pEEG-guided general anesthesia. MEASUREMENTS: Our primary endpoint was the average norepinephrine infusion rate from the beginning of induction of anesthesia until the end of surgery. MAIN RESULT: 96 patients were analyzed. The mean ± standard deviation average norepinephrine infusion rate was 0.08 ± 0.04 µg kg-1 min-1 in patients assigned to pEEG-guided and 0.12 ± 0.09 µg kg-1 min-1 in patients assigned to non-pEEG-guided general anesthesia (mean difference 0.04 µg kg-1 min-1, 95% confidence interval 0.01 to 0.07 µg kg-1 min-1, p = 0.004). Patients assigned to pEEG-guided versus non-pEEG-guided general anesthesia, had a median time-weighted minimum alveolar concentration of 0.7 (0.6, 0.8) versus 0.8 (0.7, 0.8) (p = 0.006) and a median percentage of time Patient State Index was <25 of 12 (1, 41) % versus 23 (3, 49) % (p = 0.279). CONCLUSION: pEEG-guided - compared to non-pEEG-guided - general anesthesia reduced the amount of norepinephrine needed to keep mean arterial pressure above 65 mmHg by about a third in patients having vascular surgery. Whether reduced intraoperative norepinephrine requirements resulting from pEEG-guided general anesthesia translate into improved patient-centered outcomes remains to be determined in larger trials.

Haemodynamic monitoring during noncardiac surgery: past, present, and future.

During surgery, various haemodynamic variables are monitored and optimised to maintain organ perfusion pressure and oxygen delivery - and to eventually improve outcomes. Important haemodynamic variables that provide an understanding of most pathophysiologic haemodynamic conditions during surgery include heart rate, arterial pressure, central venous pressure, pulse pressure variation/stroke volume variation, stroke volume, and cardiac output. A basic physiologic and pathophysiologic understanding of these haemodynamic variables and the corresponding monitoring methods is essential. We therefore revisit the pathophysiologic rationale for intraoperative monitoring of haemodynamic variables, describe the history, current use, and future technological developments of monitoring methods, and finally briefly summarise the evidence that haemodynamic management can improve patient-centred outcomes.

Consistency of data reporting in fluid responsiveness studies in the critically ill setting: the CODEFIRE consensus from the Cardiovascular Dynamic section of the European Society of Intensive Care Medicine.

PURPOSE: To provide consensus recommendations regarding hemodynamic data reporting in studies investigating fluid responsiveness and fluid challenge (FC) use in the intensive care unit (ICU). METHODS: The Executive Committee of the European Society of Intensive Care Medicine (ESICM) commissioned and supervised the project. A panel of 18 international experts and a methodologist identified main domains and items from a systematic literature, plus 2 ancillary domains. A three-step Delphi process based on an iterative approach was used to obtain the final consensus. In the Delphi 1 and 2, the items were selected with strong (≥ 80% of votes) or week agreement (70-80% of votes), while the Delphi 3 generated recommended (≥ 90% of votes) or suggested (80-90% of votes) items (RI and SI, respectively). RESULTS: We identified 5 main domains initially including 117 items and the consensus finally resulted in 52 recommendations or suggestions: 18 RIs and 2 SIs statements were obtained for the domain "ICU admission", 11 RIs and 1 SI for the domain "mechanical ventilation", 5 RIs for the domain "reason for giving a FC", 8 RIs for the domain pre- and post-FC "hemodynamic data", and 7 RIs for the domain "pre-FC infused drugs". We had no consensus on the use of echocardiography, strong agreement regarding the volume (4 ml/kg) and the reference variable (cardiac output), while weak on administration rate (within 10 min) of FC in this setting. CONCLUSION: This consensus found 5 main domains and provided 52 recommendations for data reporting in studies investigating fluid responsiveness in ICU patients.

Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery: Guidelines of the German Society of Anaesthesiology and Intensive Care Medicine in collaboration with the German Association of the Scientific Medical Societies.

Haemodynamic monitoring and management are cornerstones of perioperative care. The goal of haemodynamic management is to maintain organ function by ensuring adequate perfusion pressure, blood flow, and oxygen delivery. We here present guidelines on "Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery" that were prepared by 18 experts on behalf of the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und lntensivmedizin; DGAI).

The microcirculation in perioperative medicine: a narrative review.

The microcirculation describes the network of the smallest vessels in our cardiovascular system. On a microcirculatory level, oxygen delivery is determined by the flow of oxygen-carrying red blood cells in a given single capillary (capillary red blood cell flow) and the density of the capillary network in a given tissue volume (capillary vessel density). Handheld vital videomicroscopy enables visualisation of the capillary bed on the surface of organs and tissues but currently is only used for research. Measurements are generally possible on all organ surfaces but are most often performed in the sublingual area. In patients presenting for elective surgery, the sublingual microcirculation is usually intact and functional. Induction of general anaesthesia slightly decreases capillary red blood cell flow and increases capillary vessel density. During elective, even major, noncardiac surgery, the sublingual microcirculation is preserved and remains functional, presumably because elective noncardiac surgery is scheduled trauma and haemodynamic alterations are immediately treated by anaesthesiologists, usually restoring the macrocirculation before the microcirculation is substantially impaired. Additionally, surgery is regional trauma and thus likely causes regional, rather than systemic, impairment of the microcirculation. Whether or not the sublingual microcirculation is impaired after noncardiac surgery remains a subject of ongoing research. Similarly, it remains unclear if cardiac surgery, especially with cardiopulmonary bypass, impairs the sublingual microcirculation. The effects of therapeutic interventions specifically targeting the microcirculation remain to be elucidated and tested. Future research should focus on further improving microcirculation monitoring methods and investigating how regional microcirculation monitoring can inform clinical decision-making and treatment.

The Urethral Perfusion Index During Off-Pump Coronary Artery Bypass Surgery: An Observational Study.

OBJECTIVES: The IKORUS system (Vygon, Écouen, France) allows continuous monitoring of the urethral perfusion index (uPI) using a photoplethysmographic sensor mounted near the base of the balloon of a dedicated urinary catheter. We aimed to test the hypothesis that the uPI decreases during off-pump coronary artery bypass (OPCAB) surgery and to investigate the relationship between the uPI and macrocirculatory variables. DESIGN: Prospective observational study. SETTING: University Medical Center Hamburg-Eppendorf, Hamburg, Germany. PARTICIPANTS: Twenty patients having OPCAB surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary endpoint was changes in the uPI during OPCAB surgery. We additionally investigated associations between the uPI and cardiac output, mean arterial pressure, heart rate, and point-of-care variables. Twenty patients with 24,137 uPI measurements were included. Overall, there was a high interindividual variability in the uPI. Compared with the preparation phase (during which the median [interquartile range] uPI was 7.7 [5.6-12.0]), the uPI decreased by 14% (95% CI 13%-15%) during the bypass grafting phase, by 35% (95% CI 34%-36%) during the cardiac positioning phase, and by 7% (95% CI 6%-9%) during hemostasis. There was no clinically important association between uPI and either cardiac output, mean arterial pressure, or heart rate. CONCLUSIONS: The uPI decreases during OPCAB surgery, specifically during the cardiac positioning phase. There was no clinically important association between uPI and either cardiac output, mean arterial pressure, or heart rate. It, therefore, remains to be determined whether intraoperative uPI decreases are clinically important, reflect alterations in intra-abdominal tissue perfusion that are not reflected by systemic macrohemodynamics, and can help clinicians guide therapeutic interventions.

A classification system for pulmonary artery catheters.

Flow-directed, balloon-tipped pulmonary artery catheters allow measuring cardiac output and other haemodynamic variables including intracardiac pressures. We propose classifying pulmonary artery catheters by generations and specifying additional measurement modalities. Based on the method used to measure cardiac output, pulmonary artery catheters can be classified into three generations: first-generation using intermittent pulmonary artery thermodilution; second-generation using a thermal filament for automated pulmonary artery thermodilution; and third-generation combining thermal filament-based automated pulmonary artery thermodilution and pulmonary artery pulse wave analysis. Each of these pulmonary artery catheter generations can include additional measurements, such as continuous mixed venous oxygen saturation, right ventricular ejection fraction and end-diastolic volume, and right ventricular pressure. This classification should help define indications for pulmonary artery catheters in clinical practice and research.

Intraoperative hypotension when using hypotension prediction index software during major noncardiac surgery: a European multicentre prospective observational registry (EU HYPROTECT).

Background: Intraoperative hypotension is associated with organ injury. Current intraoperative arterial pressure management is mainly reactive. Predictive haemodynamic monitoring may help clinicians reduce intraoperative hypotension. The Acumen™ Hypotension Prediction Index software (HPI-software) (Edwards Lifesciences, Irvine, CA, USA) was developed to predict hypotension. We built up the European multicentre, prospective, observational EU HYPROTECT Registry to describe the incidence, duration, and severity of intraoperative hypotension when using HPI-software monitoring in patients having noncardiac surgery. Methods: We enrolled 749 patients having elective major noncardiac surgery in 12 medical centres in five European countries. Patients were monitored using the HPI-software. We quantified hypotension using the time-weighted average MAP <65 mm Hg (primary endpoint), the proportion of patients with at least one ≥1 min episode of a MAP <65 mm Hg, the number of ≥1 min episodes of a MAP <65 mm Hg, and duration patients spent below a MAP of 65 mm Hg. Results: We included 702 patients in the final analysis. The median time-weighted average MAP <65 mm Hg was 0.03 (0.00-0.20) mm Hg. In addition, 285 patients (41%) had no ≥1 min episode of a MAP <65 mm Hg; 417 patients (59%) had at least one. The median number of ≥1 min episodes of a MAP <65 mm Hg was 1 (0-3). Patients spent a median of 2 (0-9) min below a MAP of 65 mm Hg. Conclusions: The median time-weighted average MAP <65 mm Hg was very low in patients in this registry. This suggests that using HPI-software monitoring may help reduce the duration and severity of intraoperative hypotension in patients having noncardiac surgery.

Continuous Blood Pressure Monitoring in Patients Having Surgery: A Narrative Review.

Hypotension can occur before, during, and after surgery and is associated with postoperative complications. Anesthesiologists should thus avoid profound and prolonged hypotension. A crucial part of avoiding hypotension is accurate and tight blood pressure monitoring. In this narrative review, we briefly describe methods for continuous blood pressure monitoring, discuss current evidence for continuous blood pressure monitoring in patients having surgery to reduce perioperative hypotension, and expand on future directions and innovations in this field. In summary, continuous blood pressure monitoring with arterial catheters or noninvasive sensors enables clinicians to detect and treat hypotension immediately. Furthermore, advanced hemodynamic monitoring technologies and artificial intelligence-in combination with continuous blood pressure monitoring-may help clinicians identify underlying causes of hypotension or even predict hypotension before it occurs.

Intraoperative arterial pressure management: knowns and unknowns.

Preventing postoperative organ dysfunction is integral to the practice of anaesthesia. Although intraoperative hypotension is associated with postoperative end organ dysfunction, there remains ambiguity with regards to its definition, targets, thresholds for initiating treatment, and ideal treatment modalities.

Direct assessment of microcirculation in shock: a randomized-controlled multicenter study.

PURPOSE: Shock is a life-threatening condition characterized by substantial alterations in the microcirculation. This study tests the hypothesis that considering sublingual microcirculatory perfusion variables in the therapeutic management reduces 30-day mortality in patients admitted to the intensive care unit (ICU) with shock. METHODS: This randomized, prospective clinical multicenter trial-recruited patients with an arterial lactate value above two mmol/L, requiring vasopressors despite adequate fluid resuscitation, regardless of the cause of shock. All patients received sequential sublingual measurements using a sidestream-dark field (SDF) video microscope at admission to the intensive care unit (± 4 h) and 24 (± 4) hours later that was performed blindly to the treatment team. Patients were randomized to usual routine or to integrating sublingual microcirculatory perfusion variables in the therapy plan. The primary endpoint was 30-day mortality, secondary endpoints were length of stay on the ICU and the hospital, and 6-months mortality. RESULTS: Overall, we included 141 patients with cardiogenic (n = 77), post cardiac surgery (n = 27), or septic shock (n = 22). 69 patients were randomized to the intervention and 72 to routine care. No serious adverse events (SAEs) occurred. In the interventional group, significantly more patients received an adjustment (increase or decrease) in vasoactive drugs or fluids (66.7% vs. 41.8%, p = 0.009) within the next hour. Microcirculatory values 24 h after admission and 30-day mortality did not differ [crude: 32 (47.1%) patients versus 25 (34.7%), relative risk (RR) 1.39 (0.91-1.97); Cox-regression: hazard ratio (HR) 1.54 (95% confidence interval (CI) 0.90-2.66, p = 0.118)]. CONCLUSION: Integrating sublingual microcirculatory perfusion variables in the therapy plan resulted in treatment changes that do not improve survival at all.

Continuous Finger-cuff versus Intermittent Oscillometric Arterial Pressure Monitoring and Hypotension during Induction of Anesthesia and Noncardiac Surgery: The DETECT Randomized Trial.

BACKGROUND: Finger-cuff methods allow noninvasive continuous arterial pressure monitoring. This study aimed to determine whether continuous finger-cuff arterial pressure monitoring helps clinicians reduce hypotension within 15 min after starting induction of anesthesia and during noncardiac surgery. Specifically, this study tested the hypotheses that continuous finger-cuff-compared to intermittent oscillometric-arterial pressure monitoring helps clinicians reduce the area under a mean arterial pressure of 65 mmHg within 15 min after starting induction of anesthesia and the time-weighted average mean arterial pressure less than 65 mmHg during noncardiac surgery. METHODS: In this single-center trial, 242 noncardiac surgery patients were randomized to unblinded continuous finger-cuff arterial pressure monitoring or to intermittent oscillometric arterial pressure monitoring (with blinded continuous finger-cuff arterial pressure monitoring). The first of two hierarchical primary endpoints was the area under a mean arterial pressure of 65 mmHg within 15 min after starting induction of anesthesia; the second primary endpoint was the time-weighted average mean arterial pressure less than 65 mmHg during surgery. RESULTS: Within 15 min after starting induction of anesthesia, the median (interquartile range) area under a mean arterial pressure of 65 mmHg was 7 (0, 24) mmHg × min in 109 patients assigned to continuous finger-cuff monitoring versus 19 (0.3, 60) mmHg × min in 113 patients assigned to intermittent oscillometric monitoring (P = 0.004; estimated location shift: -6 [95% CI: -15 to -0.3] mmHg × min). During surgery, the median (interquartile range) time-weighted average mean arterial pressure less than 65 mmHg was 0.04 (0, 0.27) mmHg in 112 patients assigned to continuous finger-cuff monitoring and 0.40 (0.03, 1.74) mmHg in 115 patients assigned to intermittent oscillometric monitoring (P < 0.001; estimated location shift: -0.17 [95% CI: -0.41 to -0.05] mmHg). CONCLUSIONS: Continuous finger-cuff arterial pressure monitoring helps clinicians reduce hypotension within 15 min after starting induction of anesthesia and during noncardiac surgery compared to intermittent oscillometric arterial pressure monitoring.

Pulse wave analysis: basic concepts and clinical application in intensive care medicine.

PURPOSE OF REVIEW: The measurement of cardiac output ( CO ) is important in patients with circulatory shock. Pulse wave analysis (PWA) estimates CO continuously and in real-time using the mathematical analysis of the arterial pressure waveform. We describe different PWA methods and provide a framework for CO monitoring using PWA in critically ill patients. RECENT FINDINGS: PWA monitoring systems can be classified according to their invasiveness (into invasive, minimally invasive, and noninvasive systems) and their calibration method (into externally calibrated, internally calibrated, and uncalibrated systems). PWA requires optimal arterial pressure waveform signals. Marked alterations and rapid changes in systemic vascular resistance and vasomotor tone can impair the measurement performance of PWA. SUMMARY: Noninvasive PWA methods are generally not recommended in critically ill patients (who have arterial catheters anyway). PWA systems can be used to continuously track stroke volume and CO in real-time during tests of fluid responsiveness or during therapeutic interventions. During fluid challenges, continuous CO monitoring is important because - if CO decreases - a fluid challenge can be stopped early to avoid further unnecessary fluid administration. PWA externally calibrated to indicator dilution methods can be used - in addition to echocardiography - to diagnose the type of shock.

Agreement between cardiac output measurements by pulse wave analysis using the Pressure Recording Analytical Method and transthoracic echocardiography in patients with veno-venous extracorporeal membrane oxygenation therapy: An observational method comparison.

BACKGROUND: Measuring cardiac output (CO) is important in patients treated with veno-venous extracorporeal membrane oxygenation (vvECMO) because vvECMO flow and CO need to be balanced. Uncalibrated pulse wave analysis with the Pressure Recording Analytical Method (PRAM) may be suitable to measure CO in patients with vvECMO therapy. OBJECTIVE: To assess the agreement between CO measured by PRAM (PRAM-CO; test method) and CO measured by transthoracic echocardiography (TTE-CO; reference method). DESIGN: A prospective observational method comparison study. SETTING: The ICU of a German university hospital between March and December 2021. PATIENTS: Thirty one adult patients with respiratory failure requiring vvECMO therapy: 29 of the 31 patients (94%) were treated for COVID-19 related respiratory failure. MAIN OUTCOME MEASURES: PRAM-CO and TTE-CO were measured simultaneously at two time points in each patient with at least 20 min between measurements. A radial or femoral arterial catheter-derived blood pressure waveform was used for PRAM-CO measurements. TTE-CO measurements were conducted using the pulsed wave Doppler-derived velocity time integral of the left ventricular outflow tract (LVOT) and the corresponding LVOT diameter. PRAM-CO and TTE-CO were compared using Bland-Altman analysis and the percentage error (PE). We defined a PE of <30% as clinically acceptable. RESULTS: Mean ±â€ŠSD PRAM-CO was 6.86 ±â€Š1.49 l min -1 and mean TTE-CO was 6.94 ±â€Š1.58 l min -1 . The mean of the differences between PRAM-CO and TTE-CO was 0.09 ±â€Š0.73 l min -1 with a lower 95% limit of agreement of -1.34 l min -1 and an upper 95% limit of agreement of 1.51 l min -1 . The PE was 21%. CONCLUSIONS: The agreement between PRAM-CO and TTE-CO is clinically acceptable in adult patients with vvECMO therapy.

Goal-directed haemodynamic therapy: an imprecise umbrella term to avoid.

'Goal-directed haemodynamic therapy' describes various haemodynamic treatment strategies that have in common that interventions are titrated to achieve predefined haemodynamic targets. However, the treatment strategies differ substantially regarding the underlying haemodynamic target variables and target values, and thus presumably have different effects on outcome. It is an over-simplifying approach to lump complex and substantially differing haemodynamic treatment strategies together under the term 'goal-directed haemodynamic therapy', an imprecise umbrella term that we should thus stop using.