Background
Pulmonary artery thermodilution is the clinical reference method for cardiac output monitoring. Because both continuous and intermittent pulmonary artery thermodilution are used in clinical practice it is important to know whether cardiac output measurements by the two methods are clinically interchangeable.
Methods
We performed a systematic review and meta-analysis of clinical studies comparing cardiac output measurements assessed using continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients. 54 studies with 1522 patients were included in the analysis.
Results
The heterogeneity across the studies was high. The overall random effects model-derived pooled estimate of the mean of the differences was 0.08 (95%-confidence interval 0.01 to 0.16) L/min with pooled 95%-limits of agreement of − 1.68 to 1.85 L/min and a pooled percentage error of 29.7 (95%-confidence interval 20.5 to 38.9)%.
Conclusion
The heterogeneity across clinical studies comparing continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients is high. The overall trueness/accuracy of continuous pulmonary artery thermodilution in comparison with intermittent pulmonary artery thermodilution is good (indicated by a pooled mean of the differences < 0.1 L/min). Pooled 95%-limits of agreement of − 1.68 to 1.85 L/min and a pooled percentage error of 29.7% suggest that continuous pulmonary artery thermodilution barely passes interchangeability criteria with intermittent pulmonary artery thermodilution.
PROSPERO registration number CRD42020159730.
Background
Intraoperative hypotension is common in patients having non-cardiac surgery and is associated with serious complications and death. However, optimal intraoperative blood pressures for individual patients remain unknown. We therefore aim to test the hypothesis that personalized perioperative blood pressure management—based on preoperative automated blood pressure monitoring—reduces the incidence of a composite outcome of acute kidney injury, acute myocardial injury, non-fatal cardiac arrest, and death within 7 days after surgery compared to routine blood pressure management in high-risk patients having major abdominal surgery.
Methods
IMPROVE-multi is a multicenter randomized trial in 1272 high-risk patients having elective major abdominal surgery that we plan to conduct at 16 German university medical centers. Preoperative automated blood pressure monitoring using upper arm cuff oscillometry will be performed in all patients for one night to obtain the mean of the nighttime mean arterial pressures. Patients will then be randomized either to personalized blood pressure management or to routine blood pressure management. In patients assigned to personalized management, intraoperative mean arterial pressure will be maintained at least at the mean of the nighttime mean arterial pressures. In patients assigned to routine management, intraoperative blood pressure will be managed per routine. The primary outcome will be a composite of acute kidney injury, acute myocardial injury, non-fatal cardiac arrest, and death within 7 days after surgery.
Discussion
Our trial will determine whether personalized perioperative blood pressure management reduces the incidence of major postoperative complications and death within 7 days after surgery compared to routine blood pressure management in high-risk patients having major abdominal surgery.
Trial registration
ClinicalTrials.gov NCT05416944. Registered on June 14, 2022.
BACKGROUND: Cardiac output is an important hemodynamic variable and determines oxygen delivery. In contrast to blood pressure, cardiac output is rarely measured even in high-risk surgical patients, suggesting that clinicians consider blood pressure to be a reasonable indicator of systemic blood flow. However, the relationship depends on constant vascular tone and volume, both of which routinely vary during anesthesia and surgery. We therefore tested the hypothesis that there is no clinically meaningful correlation between mean arterial pressure and cardiac index in major abdominal surgery patients. METHODS: In this prospective observational study, we assessed the relationship between mean arterial pressure and cardiac index in 100 patients having major abdominal surgery under general anesthesia. RESULTS: The pooled within-patient correlation coefficient calculated using meta-analysis methods was r = 0.34 (95% confidence interval, 0.28-0.40). Linear regression using a linear mixed effects model of cardiac index on mean arterial pressure revealed that cardiac index increases by 0.014 L•min −1 •m −2 for each 1 mm Hg increase in mean arterial pressure. The 95% Wald confidence interval of this slope was 0.011 to 0.018 L•min −1 •m −2 •mm Hg −1 and thus within predefined equivalence margins of −0.03 and 0.03 L•min −1 •m −2 •mm Hg −1 , thereby demonstrating lack of clinically meaningful association between mean arterial pressure and cardiac index. CONCLUSIONS: There is no clinically meaningful correlation between mean arterial pressure and cardiac index in patients having major abdominal surgery. Intraoperative blood pressure is thus a poor surrogate for cardiac index. (Anesth Analg 2022;134:322-9)
KEY POINTS• Question: What is the relationship between mean arterial pressure and cardiac index in patients having major abdominal surgery under general anesthesia? • Findings: There was no clinically meaningful correlation between mean arterial pressure and cardiac index in patients having major abdominal surgery. • Meaning: Mean arterial pressure should not be considered even a rough indicator of cardiac index.
GLOSSARYCI = cardiac index; CO = cardiac output; MAP = mean arterial pressure; STROBE = Strenghtening the Reporting of Observational Studies in Epidemiology; SVR = systemic vascular resistance C ardiac output (CO) is an important hemodynamic variable because CO-together with arterial oxygen content-determines oxygen delivery. 1 CO-guided hemodynamic management may improve postoperative outcomes in high-risk surgical patients. 2,3
A solid understanding of basic sciences is a prerequisite for successful completion of medical education. Therefore, it is essential to improve the quality of teaching and to ensure the applicability of basic sciences. Based on practical experiences and previous research, we developed an innovative step-by-step concept, called ENHANCE, for the implementation or revision of teaching units, especially for basic sciences. We used comparative self-assessment gains, a questionnaire to assess teaching quality as well as end-of-semester evaluations (students' satisfaction and open-ended questions) to evaluate the ENHANCE concept. It was found that ENHANCE-based teaching units were related to increased students' satisfaction, high attendance rates and that restructuring the course curriculum yielded in a positive assessment of teaching effectiveness. The revised courses were rated as the very best of all classes in several semesters. Qualitative data showed that students particularly appreciated the level of comprehension and how helpful the courses were for the understanding and preparation of the regular curriculum.
Acute myocardial injury is common after noncardiac surgery and associated with mortality. Impaired intraoperative cardiovascular dynamics are a risk factor for acute myocardial injury. Optimizing intraoperative cardiovascular dynamics may thus reduce acute myocardial injury. We aimed to investigate the effect of intraoperative personalized goal-directed hemodynamic management on the incidence of acute myocardial injury. We hypothesized that personalized goal-directed hemodynamic management reduces the incidence of acute myocardial injury compared to routine hemodynamic management in high-risk patients having major abdominal surgery. We performed a post-hoc secondary analysis of a randomized clinical trial including 180 high-risk major abdominal surgery patients that were randomized to personalized goal-directed hemodynamic management or routine hemodynamic management. We compared the incidences of acute myocardial injury—defined according to the Fourth Universal Definition of Myocardial Infarction (2018)—between patients randomized to personalized goal-directed hemodynamic management or routine hemodynamic management by calculating the relative and absolute risk reduction together with 95% Wald confidence intervals and P values. Acute myocardial injury occurred in 4 of 90 patients (4%) in the personalized goal-directed hemodynamic management group and in 12 of 90 patients (13%) in the routine hemodynamic management group (relative risk: 0.33, 95% confidence interval: 0.11 to 0.99, P = 0.036; absolute risk reduction: − 9%, 95% confidence interval: − 17% to − 0.68%, P = 0.034). In this post-hoc secondary analysis, intraoperative personalized goal-directed hemodynamic management reduced the incidence of acute myocardial injury compared to routine hemodynamic management in high-risk patients having major abdominal surgery. This needs to be confirmed in larger prospective trials.
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