Optimal Mean Arterial Pressure Research Articles

Continuous Monitoring of Cerebral Autoregulation in Adults Supported by Extracorporeal Membrane Oxygenation.

Impaired cerebral autoregulation (CA) is one of several proposed mechanisms of acute brain injury in patients supported by extracorporeal membrane oxygenation (ECMO). The primary aim of this study was to determine the feasibility of continuous CA monitoring in adult ECMO patients. Our secondary aims were to describe changes in cerebral oximetry index (COx) and other metrics of CA over time and in relation to functional neurologic outcomes. This is a single-center prospective observational study. We measured COx, a surrogate measurement of cerebral blood flow measured by near-infrared spectroscopy, which is an index of CA derived from the moving correlation between mean arterial pressure (MAP) and slow waves of regional cerebral oxygen saturation. A COx value that approaches 1 indicates impaired CA. Using COx, we determined the optimal MAP (MAPOPT) and lower and upper limits of autoregulation for individual patients. These measurements were examined in relation to modified Rankin Scale (mRS) scores. Fifteen patients (median age 57years [interquartile range 47-69]) with 150 autoregulation measurements were included for analysis. Eleven were on veno-arterial ECMO (VA-ECMO), and four were on veno-venous ECMO (VV-ECMO). Mean COx was higher on postcannulation day 1 than on day 2 (0.2 vs. 0.09, p < 0.01), indicating improved CA over time. COx was higher in VA-ECMO patients than in VV-ECMO patients (0.12 vs. 0.06, p = 0.04). Median MAPOPT for the entire cohort was highly variable, ranging from 55 to 110mm Hg. Patients with mRS scores 0-3 (good outcome) at 3 and 6months spent less time outside MAPOPT compared with patients with mRS scores 4-6 (poor outcome) (74% vs. 82%, p = 0.01). The percentage of time when observed MAP was outside the limits of autoregulation was higher on postcannulation day 1 than on day 2 (18.2% vs. 3.3%, p < 0.01). In ECMO patients, it is feasible to monitor CA continuously at the bedside. CA improved over time, most significantly between postcannulation days 1 and 2. CA was more impaired in VA-ECMO patients than in VV-ECMO patients. Spending less time outside MAPOPT may be associated with achieving a good neurologic outcome.

Preserving flow, saving lives: Successful treatment of aortic valve failure in acute myocardial infarction without flow down-regulation using ECMO - a case report and mini review.

Direct percutaneous coronary intervention (PPCI) has significantly reduced cardiac mortality in patients with acute myocardial infarction (AMI), but the mortality rate remains high for those who develop cardiogenic shock (CS), reaching 40% to 50%. Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) provides robust hemodynamic support and oxygen delivery for AMI patients with refractory CS, ensuring adequate organ perfusion and oxygen supply. However, there is currently no standardized optimal Mean Arterial Pressure (MAP) range during V-A ECMO support. Achieving the proper MAP is crucial for adequate myocardial perfusion, cardiac function recovery, successful weaning off of V-A ECMO, and improving long-term outcomes. In this case study, we successfully treated a 55-year-old man with AMI and refractory cardiogenic shock using V-A ECMO. By adjusting ECMO blood flow and employing hemodynamic strategies, including vasoactive drugs, we optimized the MAP, leading to improved cardiac function and successful weaning off of V-A ECMO. This presents a potential opportunity for MAP optimization under ECMO support in patients with acute myocardial infarction and cardiogenic shock.

Abstract WP152: Association Between Cerebrospinal Fluid Interleukin-6 Levels and Cerebral Autoregulation After Aneurysmal Subarachnoid Hemorrhage

Introduction: Elevated levels of Interleukin-6 (IL-6) levels in cerebrospinal fluid (CSF) have been correlated with delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). However, the role of neuroinflammation in SAH pathophysiology remains incompletely understood. In a pig stroke model, IL-6 antagonist prevented hypotension-induced pial artery impairment, suggesting a role in post-stroke vascular derangement. This research assesses serial CSF IL-6 levels' relationship with cerebral autoregulation in aSAH patients. Methods: We prospectively enrolled aSAH patients at Yale-New Haven Hospital. Autoregulatory function was measured by interrogating changes in near-infrared spectroscopy-derived tissue oxygenation response to changes in mean arterial pressure (MAP). The resulting autoregulatory index was used to trend the MAP range at which autoregulation was most preserved. Percent time that MAP exceeded the upper limit of autoregulation or decreased below the lower limit of autoregulation was calculated for each patient. IL-6 levels were assessed through serial CSF samples and correlated with hemodynamic parameters. Results: We calculated limits of autoregulation for twenty-two patients (mean age 60 ± 9 years, mean Hunt Hess score 3.4 ± 1.2, mean modified Fisher score 3.7 ± 0.58, average monitoring time 10.1 ± 7.3 hours). Optimal MAP and limits were calculated an average of 74% ± 20% of monitoring time. Our study provides preliminary support for a potential association between IL-6 levels and percent time that MAP was within limits of autoregulation (b = -0.31, p=0.009, Fig. 1A). Additionally, there was a significant correlation between IL-6 levels and the extent to which MAP deviated from computed optimal MAP (r= 0.636, p=0.009, Fig. 1B). Conclusions: IL-6 may contribute to impaired autoregulation post aSAH. Further studies are needed to validate findings and refine MAP management for improved outcomes in aSAH patients.

High versus standard blood pressure target in hypertensive high-risk patients undergoing elective major abdominal surgery: a study protocol for the HISTAP randomized clinical trial

BackgroundThe intraoperative period is often characterized by hemodynamic instability, and intraoperative hypotension is a common complication. The optimal mean arterial pressure (MAP) target in hypertensive patients is still not clear. We hereby describe the protocol and detailed statistical analysis plan for the high versus standard blood pressure target in hypertensive high-risk patients undergoing elective major abdominal surgery: the HISTAP randomized clinical trial. The HISTAP trial aims at addressing whether the use of a higher intraoperative MAP target in high-risk hypertensive surgical patients scheduled for elective abdominal surgery would improve postoperative outcomes, as compared to the standard and recommended perioperative MAP, by using a composite outcome including a 30-day mortality from surgical intervention and at least one major organ dysfunction or new onset of sepsis and septic shock occurring 7 days after surgery.MethodsThe HISTAP trial is an investigator-initiated, pragmatic, parallel-grouped, randomized, stratified, analyst-blinded trial with adequate allocation sequence generation, and allocation concealment. We will allocate 636 patients to a MAP target ≥ 80 mmHg (treatment group) or to a MAP target ≥65 mmHg (control group). The primary outcome is a composite outcome including a 30-day mortality from the operation and major organ complications. Secondary outcomes are mortality at 30 days, intensive care unit (ICU) length of stay, ICU readmission, Sequential Organ Failure Assessment (SOFA) scores recorded up to postoperative day 7, overall intraoperative fluid balance, vasopressors use, and the need for reoperation. An unadjusted χ2 test will be used for the primary outcome analysis. A Cox proportional hazards model will be used to adjust the association between the primary outcome and baseline covariates.ConclusionsThe HISTAP trial results will provide important evidence to guide clinicians’ choice regarding the intraoperative MAP target in high-risk hypertensive patients scheduled for elective abdominal surgery.

Determining Optimal Mean Arterial Blood Pressure Based on Cerebral Autoregulation in Children after Cardiac Surgery.

To evaluate the feasibility of continuous determination of the optimal mean arterial blood pressure (opt-MAP) according to cerebral autoregulation and to describe the opt-MAP, the autoregulation limits, and the time spent outside these limits in children within 48h of cardiac surgery. Cerebral autoregulation was assessed using the correlation coefficient (COx) between cerebral oxygenation and MAP in children following cardiac surgery. Plots depicting the COx according to the MAP were used to determine the opt-MAP using weighted multiple time windows. For each patient, we estimated (1) the time spent with MAP outside the autoregulation limits and (2) the burden of deviation, defined as the area between the MAP curve and the autoregulation limits when the MAP was outside these limits. Fifty-one patients with a median age of 7.1 (IQR 0.7-52.0) months old were included. The opt-MAP was calculated for 94% (IQR 90-96) of the monitored time. The opt-MAP was significantly lower in neonates < 1month old. The patients spent 24% (18-31) of the time outside of the autoregulation limits, with no significant differences between age groups. Continuous determination of the opt-MAP is feasible in children within the first 48h following cardiac surgery.

High versus low mean arterial pressure targets after out-of-hospital cardiac arrest: a meta-analysis of randomized controlled trials

Abstract Background Out-of-hospital cardiac arrest (OHCA) is a significant healthcare burden, with an average global incidence of 55 per 100,000 person-years among adults. OHCA patients require blood pressure support to maintain effective mean arterial pressure (MAP) for cerebral reperfusion, which is usually achieved by intravascular fluids and vasopressors in the intensive care unit (ICU). Targeting a specific MAP has been evaluated as a treatment strategy after OHCA; however, the current evidence lacks clear guidelines regarding the optimal MAP target after OHCA. Purpose We aim to evaluate the efficacy of targeting a high MAP (&amp;gt;70 mmHg) versus a low MAP target (&amp;lt; 65 mmHg) after OHCA resuscitation. Methods We conducted a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs), which were retrieved by systematically searching: PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane through January 18th, 2023. Continuous and dichotomous outcomes were pooled using mean difference (MD) and risk ratio (RR) along with confidence interval (CI), using Revman V. 5.4 software. Our review protocol was prospectively published on PROSPERO with ID: CRD42023395333. Results Four RCTs with a total of 1070 patients (531 in the high MAP target group and 534 in the low MAP target group) were included in our analysis. High MAP target was significantly associated with decreased ICU length of stay (MD: -0.78 with a 95 CI [-1.54, -0.02], P= .04) and mechanical ventilation duration (MD: -0.91 with a 95 CI of [-1.51, -0.31], P= .003). However, There was no difference between targeting a high MAP versus low MAP regarding all-cause mortality (RR: 1.07 with a 95% CI [0.91, 1.27], P= 0.4), favorable neurological recovery (cerebral categories scale (CPC) ≤ 2) (RR: 1.02 with a 95% CI [0.93, 1.13], P= 0.68), and neuron-specific enolase (NSE) at 48 hours (MD: 0.54 with 95% CI [-1.67, 2.75], P = 0.63), the incidence of adverse events, including any bleeding (RR: 0.89 with a 95% CI [0.69, 1.36], P= 0.39); arrhythmia (RR: 0.91 with a 95% CI [0.46, 1.82], P= 0.79), or acute kidney injury (RR: 0.80 with a 95% CI [0.36, 1.76] and P = 0.58). Conclusion In patients with OHCA who have been resuscitated, targeting a higher MAP significantly reduced the ICU length of stay and mechanical ventilation, implying potential clinical benefit with an acceptable safety margin. However, there was no difference between targeting a high MAP versus a low MAP regarding all-cause mortality, favorable neurological recovery, and NSE. Therefore, further RCTs are still warranted to elucidate the potential clinical benefit of targeting a high MAP after OHCA before endorsement in clinical practice.Figure 1Figure 2

Abstract 135: Identifying Optimal Mean Arterial Pressure in Cardiac Arrest Patients: Are Precision Medicine Approaches Feasible?

Introduction: Loss of cerebral autoregulation after cardiac arrest (CA) is associated with worse outcomes. A population-based mean arterial pressure (MAP) threshold, such as a post-resuscitation goal of ≥ 65 mmHg, may be insufficient to account for patient-specific factors, like autoregulatory failure. We investigated the feasibility of determining optimal MAP (MAP OPT ) using regional cerebral tissue oxygen monitoring with near-infrared spectroscopy (NIRS). Hypothesis: Autoregulatory failure and MAP OPT can be identified in individual patients after CA. Methods: We prospectively enrolled adult comatose CA survivors undergoing invasive MAP and regional cerebral oxygen monitoring with NIRS in an ICU between April 2022 and May 2023. Tissue oxygenation autoregulatory index (TOx) was derived using a moving Pearson correlation coefficient of 30 consecutive, 10-second averaged values of MAP and tissue oxygen index signals. TOx ≥ 0.3 defined impaired autoregulation. MAP values were divided into bins of 5 mmHg for which each corresponding TOx was averaged. Parabolic curve fitting determined the MAP value with the lowest associated TOx value (MAP OPT ). Results: Of 35 patients enrolled, 74.3% experienced out-of-hospital cardiac arrest with a mean (SD) age of 55.0 (13.9) years. Six (17.1%) patients survived to hospital discharge and 4 (11.4%) progressed to brain death. Monitoring was initiated at a median [IQR] of 14.9 [10.9 - 20.6] hours from CA for a duration of 47.5 [27.1 - 75.1] hours. The time spent with impaired autoregulation was 22.6 [18.4 - 31.6] % of the recording duration, corresponding to 10.1 [6.9 - 15.9] hours. MAP OPT could be identified in 33 (94.3%) patients and 47.7 [32.1 - 59.6] % of the recording duration. The average MAP OPT was &lt;75 mmHg in 2 (6.1%), 75 - 85 mmHg in 14 (42.4%), and &gt;85 mmHg in 17 (51.5%) patients. MAP OPT did not differ between survivors and non-survivors (mean (SD) 87.2 (9.6) vs. 88.2 (12.1) mmHg respectively, p=0.86). Conclusion: MAP OPT could be identified in all but two patients and calculated for half of the recording duration. Average MAP OPT was ≥ 75 mmHg in 94% of our cohort. Future studies are needed to evaluate whether targeting personalized physiologic thresholds influences outcomes.

Assessing the optimal MAP target in pre-capillary PH patients with RV failure: A retrospective analysis.

Right ventricular failure (RVF) in pre-capillary pulmonary hypertension (PH) is associated with high morbidity and mortality. While mean arterial pressure (MAP) goals have been well established in critical care literature, the optimal MAP target for patients with RVF secondary to pre-capillary PH remains unknown. The objective of this study was to evaluate the difference in outcomes between patients who were managed with different MAP targets. We retrospectively analyzed records of 60 patients who were admitted to the intensive care unit for decompensated RVF secondary to pre-capillary PH. The records were stratified into two groups: 30 patients who were treated with a static MAP goal of either 65 or 70 mmHg (MAP65/70) and 30 patients who received a dynamic MAP goal (MAPCVP) determined by invasively obtained central venous pressure or right atrial pressure. The dynamic MAP group had a statistically significant decrease in in-hospital mortality and incidence of acute kidney injury compared to the static MAP cohort.

Association between Peripartum Mean Arterial Pressure and Postpartum Readmission for Preeclampsia with Severe Features.

This study aimed to evaluate the relationship between peripartum mean arterial pressure (MAP) and postpartum readmission for preeclampsia with severe features. This is a retrospective case-control study comparing adult parturients readmitted for preeclampsia with severe features to matched nonreadmitted controls. Our primary objective was to evaluate the association between MAP at three time points during the index hospitalization (admission, 24-hour postpartum, and discharge) and readmission risk. We also evaluated readmission risk by age, race, body mass index, and comorbidities. Our secondary aim was to establish MAP thresholds to identify the population at highest risk of readmission. Multivariate logistic regression and chi-squared tests were used to determine the adjusted odds of readmission based on MAP. Receiver operating characteristic analyses were performed to evaluate risk of readmission relative to MAP; optimal MAP thresholds were established to identify those at highest risk of readmission. Pairwise comparisons were made between subgroups after stratifying for history of hypertension, with a focus on readmitted patients with new-onset postpartum preeclampsia. A total of 348 subjects met inclusion criteria, including 174 controls and 174 cases. We found that elevated MAP at both admission (adjusted odds ratio [OR]: 1.37 per 10 mm Hg, p < 0.0001) and 24-hour postpartum (adjusted OR: 1.61 per 10 mm Hg, p = 0.0018) were associated with increased risk of readmission. African American race and hypertensive disorder of pregnancy were independently associated with increased risk of readmission. Subjects with MAP > 99.5 mm Hg at admission or >91.5 mm Hg at 24-hour postpartum had a risk of at least 46% of requiring postpartum readmission for preeclampsia with severe features. Admission and 24-hour postpartum MAP correlate with risk of postpartum readmission for preeclampsia with severe features. Evaluating MAP at these time points may be useful for identifying women at higher risk for postpartum readmission. These women may otherwise be missed based on standard clinical approaches and may benefit from heightened surveillance. · Existing literature focuses on management of antenatal hypertensive disorders of pregnancy.. · Elevated peripartum MAP is associated with increased odds of readmission for preeclampsia.. · Peripartum MAP may predict readmission risk for de novo postpartum preeclampsia..

Current insights into the management of spinal cord injury

BackgroundTraumatic spinal cord injury (SCI) is a serious disorder that results in severe impairment of neurological function as well as disability, ultimately reducing a patient's quality of life. The pathophysiology of SCI involves a primary and secondary phase, which causes neurological injury. MethodsNarrative review on current clinical management of spinal cord injury and emerging therapies. ResultsThis review explores the management of SCI through early decompressive surgery, optimizing mean arterial pressure, steroid therapy and focused rehabilitation. These management strategies reduce secondary injury mechanisms to prevent the propagation of further neurological damage. The literature regarding emerging research is also explored in cell-based, gene, pharmacological and neuromodulation therapies, which aim to repair the spinal cord following the primary injury mechanism. ConclusionsOutcomes for patients with SCI can be enhanced and improved if primary and secondary phases of SCI can be addressed.

Noninvasive neurological monitoring to enhance pLVAD-assisted ventricular tachycardia ablation - a Mini review.

For critically ill patients, hemodynamic fluctuations can be life-threatening; this is particularly true for patients experiencing cardiac comorbidities. Patients may suffer from problems with heart contractility and rate, vascular tone, and intravascular volume, resulting in hemodynamic instability. Unsurprisingly, hemodynamic support provides a crucial and specific benefit during percutaneous ablation of ventricular tachycardia (VT). Mapping, understanding, and treating the arrhythmia during sustained VT without hemodynamic support is often infeasible due to patient hemodynamic collapse. Substrate mapping in sinus rhythm can be successful for VT ablation, but there are limitations to this approach. Patients with nonischemic cardiomyopathy may present for ablation without exhibiting useful endocardial and/or epicardial substrate-based ablation targets, either due to diffuse extent or a lack of identifiable substrate. This leaves activation mapping during ongoing VT as the only viable diagnostic strategy. By enhancing cardiac output, percutaneous left ventricular assist devices (pLVAD) may facilitate conditions for mapping that would otherwise be incompatible with survival. However, the optimal mean arterial pressure to maintain end-organ perfusion in presence of nonpulsatile flow remains unknown. Near infrared oxygenation monitoring during pLVAD support provides assessment of critical end-organ perfusion during VT, enabling successful mapping and ablation with the continual assurance of adequate brain oxygenation. This focused review provides practical use case scenarios for such an approach, which aims to allow mapping and ablation of ongoing VT while drastically reducing the risk of ischemic brain injury.

Responsiveness to Vasoconstrictor Therapy in Hepatorenal Syndrome Type 1.

Raising mean arterial pressure (MAP) during treatment of hepatorenal syndrome type 1 (HRS-1) with vasoconstrictors is associated with renal recovery. However, the optimal MAP target and factors associated with response to vasoconstrictors remain unclear. Records from hospitalized patients with HRS-1 treated with vasoconstrictors without shock were reviewed searching for those who achieved ≥5 mmHg rise in MAP within 48 hours. We examined the relationship between the mean MAP achieved during the first 48-72 hours of vasoconstrictor therapy and the change in serum creatinine (sCr) up to day 14. Endpoints were >30% reduction in sCr without need for dialysis or death by day 14 (primary) or by day 30 (secondary). Seventy-seven patients with HRS-1 treated for 2-10 days with either norepinephrine (n=49) or midodrine/octreotide (n=28) were included. Median age was 52 (IQR 46-60), 40% were female and 48% had alcoholic cirrhosis. At vasoconstrictor initiation, median MAP was 70 mmHg (IQR 66-73) and median sCr was 3.8 mg/dL (IQR 2.6-4.9). When analyzed by tertiles of mean MAP increment (5-9, 10-14, ≥15 mmHg), there was greater reduction in sCr with greater rise in MAP (ANOVA for trend, p<0.0001). By multivariate logistic regression analysis, mean MAP rise during the first 48-72 hrs [OR 1.15 (1.02 - 1.299), p=0.025], norepinephrine as vasoconstrictor [OR 5.46 (1.36-21.86), p=0.017] and baseline sCr [OR 0.63 (0.41-0.97), p=0.034] were associated with the primary endpoint; whereas mean MAP rise during the first 48-72 hrs [OR 1.17 (1.04-1.33), p=0.012] and baseline sCr [OR 0.63 (0.39-0.98), p=0.043] were associated with the secondary endpoint. Greater magnitude of rise in MAP with vasoconstrictor therapy in HRS-1, lower baseline sCr, and use of norepinephrine over midodrine/octreotide are associated with kidney recovery. Targeting an increment of MAP ≥15 mmHg may lead to favorable renal outcomes.

Multimodal interventions to optimize spinal cord perfusion in patients with acute traumatic spinal cord injuries: a systematic review.

The authors systematically reviewed current evidence for the utility of mean arterial pressure (MAP), intraspinal pressure (ISP), and spinal cord perfusion pressure (SCPP) as predictors of outcomes after traumatic spinal cord injury (SCI). PubMed, Cochrane Reviews Library, EMBASE, and Scopus databases were queried in December 2020. Two independent reviewers screened articles using Covidence software. Disagreements were resolved by a third reviewer. The inclusion criteria for articles were 1) available in English; 2) full text; 3) clinical studies on traumatic SCI interventions; 4) involved only human participants; and 5) focused on MAP, ISP, or SCPP. Exclusion criteria were 1) only available in non-English languages; 2) focused only on the brain; 3) described spinal diseases other than SCI; 4) interventions altering parameters other than MAP, ISP, or SCPP; and 5) animal studies. Studies were analyzed qualitatively and grouped into two categories: interventions increasing MAP or interventions decreasing ISP. The Scottish Intercollegiate Guidelines Network level of evidence was used to assess bias and the Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate confidence in the anticipated effects of each outcome. A total of 2540 unique articles were identified, of which 72 proceeded to full-text review and 24 were included in analysis. One additional study was included retrospectively. Articles that went through full-text review were excluded if they were a review paper (n = 12), not a full article (n = 12), a duplicate paper (n = 9), not a human study (n = 3), not in English (n = 3), not pertaining to traumatic SCI (n = 3), an improper intervention (n = 3), without intervention (n = 2), and without analysis of intervention (n = 1). Although maintaining optimal MAP levels is the current recommendation for SCI management, the published literature supports maintenance of SCPP as a stronger indicator of favorable outcomes. Studies also suggest that laminectomy and durotomy may provide better outcomes than laminectomy alone, although higher-level studies are needed. Current evidence is inconclusive on the effectiveness of CSF drainage for reducing ISP. This review demonstrates the importance of assessing how different interventions may vary in their ability to optimize SCPP.

Identifying the optimal blood pressure for cerebral autoregulation in infants after cardiac surgery by monitoring cerebrovascular reactivity-A pilot study.

Advances in the treatment of pediatric congenital heart disease have increased survival rates. Despite efforts to prevent neurological injury, many patients suffer from impaired neurodevelopmental outcomes. Compromised cerebral autoregulation can increase the risk of brain injury following pediatric cardiac surgery with cardiopulmonary bypass. Monitoring autoregulation and maintaining adequate cerebral blood flow can help prevent neurological injury. Our objective was to evaluate autoregulation parameters and to define the optimal blood pressure as well as the lower and upper blood pressure limits of autoregulation. Autoregulation was monitored prospectively in 36 infants after cardiopulmonary bypass surgery for congenital heart defects between January and December 2019. Autoregulation indices were calculated by correlating invasive arterial blood pressure, cortical oxygen saturation, and relative tissue hemoglobin levels with near-infrared spectroscopy parameters. The mean patient age was 4.1 ± 2.8months, and the mean patient weight was 5.2 ± 1.8kg. Optimal mean arterial pressure could be identified in 88.9% of patients via the hemoglobin volume index and in 91.7% of patients via the cerebral oxygenation index, and a lower limit of autoregulation could be found in 66.7% and 63.9% of patients, respectively. No significant changes in autoregulation indices at the beginning or end of the monitoring period were observed. In 76.5% ± 11.1% and 83.8% ± 9.9% of the 8 and 16 h monitoring times, respectively, the mean blood pressure was inside the range of intact autoregulation (below in 21.5% ± 25.4% and 11.3% ± 16.5% and above in 8.7% ± 10.4% and 6.0% ± 11.0%, respectively). The mean optimal blood pressure was 57.4 ± 8.7 mmHg and 58.2 ± 7.9 mmHg and the mean lower limit of autoregulation was 48.8 ± 8.3 mmHg and 45.5 ± 6.7 mmHg when generated via the hemoglobin volume index and cerebral oxygenation index, respectively. Postoperative noninvasive autoregulation monitoring after cardiac surgery in children can be reliably and safely performed using the hemoglobin volume index and cerebral oxygenation index and provides robust data. This monitoring can be used to identify individual hemodynamic targets to optimize autoregulation, which differs from those recommended in the literature. Further evaluation of this subject is needed.

Impact of early mean arterial pressure level on severe acute kidney injury occurrence after out-of-hospital cardiac arrest

BackgroundThe optimal early mean arterial pressure (MAP) level in terms of renal function remains to be established in patients with out-of-hospital cardiac arrest (OHCA). We aimed to evaluate the association between early MAP level and severe acute kidney injury (AKI) occurrence in patients with OHCA.ResultsIn 568 consecutive patients, the percentage time spent below a predefined MAP threshold and the corresponding area below threshold (ABT) were calculated from continuous MAP measurement. Both MAP-derived variables were calculated for different MAP thresholds (65, 75 and 85 mmHg) and time periods (the first 6 and 12 after ICU admission). 274 (48%) patients developed severe AKI defined as stage 3 of KDIGO. Both ABT and percentage time were independently associated with severe AKI, regardless of the MAP threshold and time period considered. Highest adjusted odds ratios for developing severe AKI were observed while considering the first 6 h period. Within the first 6 h, every 100 mmHg-h increase in ABT under MAP thresholds of 65, 75 and 85 mmHg increased severe AKI risk by 69% (OR = 1.69; 95% CI 1.26–2.26; p < 0.01), 13% (OR = 1.13; 95% CI 1.07–1.20; p < 0.01) and 4% (OR = 1.04; 95% CI 1.02–1.06; p < 0.01), respectively. Every 10% increase in percentage time spent under MAP thresholds of 65, 75 and 85 mmHg increased severe AKI risk by 19% (OR = 1.19; 95% CI 1.06–1.33; p < 0.01), 12% (OR = 1.12; 95% CI 1.04–1.19; p < 0.01) and 8% (OR = 1.08; 95% CI 1.02–1.14; p < 0.01), respectively.ConclusionsBoth severity and duration of early arterial hypotension after ICU admission remained associated with severe AKI occurrence while considering a MAP threshold as high as 85 mmHg after OHCA.

Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery

BackgroundCardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery. MethodsAutoregulation was measured during cardiac surgery in 240 patients. Mean flow index and cerebral oximetry index were calculated as Pearson's correlations between mean arterial pressure (MAP) and transcranial Doppler blood flow velocity or near-infrared spectroscopy signals. The lower limit of autoregulation and optimal mean arterial pressure were identified using mean flow index and cerebral oximetry index. Regression models were used to examine associations of area under curve and duration of mean arterial pressure below thresholds with stroke, acute kidney injury (AKI), and major morbidity and mortality. ResultsBoth mean flow index and cerebral oximetry index identified the cerebral lower limit of autoregulation below which MAP was associated with a higher incidence of AKI and major morbidity and mortality. Based on magnitude and significance of the estimates in adjusted models, the area under curve of MAP < lower limit of autoregulation had the strongest association with AKI and major morbidity and mortality. The odds ratio for area under the curve of MAP < lower limit of autoregulation was 1.05 (95% confidence interval, 1.01–1.09), meaning every 1 mm Hg h increase of area under the curve was associated with an average increase in the odds of AKI by 5%. ConclusionsFor cardiac surgery patients, area under curve of MAP < lower limit of autoregulation using mean flow index or cerebral oximetry index had the strongest association with AKI and major morbidity and mortality. Trials are necessary to evaluate this target for MAP management.

Influence of Intraoperative Hemodynamic Parameters on Outcome in Simultaneous Pancreas-Kidney Transplant Recipients.

Objectives: Adequate organ perfusion, as well as appropriate blood pressure levels at the time of unclamping, is crucial for early and long-term graft function and outcome in simultaneous pancreas–kidney transplantation (SPKT). However, the optimal intraoperative mean arterial pressure (MAP) level has not well been defined. Methods: From a prospectively collected database, the medical data of 105 patients undergoing SPKT at our center were retrospectively analyzed. A receiver operating characteristic (ROC) analysis was preliminarily performed for optimal cut-off value for MAP at reperfusion, to predict early pancreatic graft function. Due to these results, we divided the patients according to their MAP values at reperfusion into <91 mmHg (n = 47 patients) and >91 mmHg (n = 58 patients) groups. Clinicopathological characteristics and outcomes, as well as early graft function and long-term survival, were retrospectively analyzed. Results: Donor and recipient characteristics were comparable between both groups. Rates of postoperative complications were significantly higher in the <91 mmHg group than those in the >91 mmHg group (vascular thrombosis of the pancreas: 7 (14%) versus 2 (3%); p = 0.03; pancreatitis/intraabdominal abscess: 10 (21%) versus 4 (7%); p = 0.03; renal delayed graft function (DGF): 11 (23%) versus 5 (9%); p = 0.03; postreperfusion urine output: 106 ± 50 mL versus 195 ± 45 mL; p = 0.04). There were no significant differences in intraoperative volume repletion, central venous pressure (CVP), use of vasoactive inotropic agents, and the metabolic outcome. Five-year pancreas graft survival was significantly higher in the >91 mmHg group (>91 mmHg: 82% versus <91 mmHg: 61%; p < 0.01). No significant differences were observed in patient and kidney graft survival at 5 years between both groups. Multivariate Cox regression analysis affirmed MAP < 91 mmHg as an independent prognostic predictor for renal DGF (HR 3.49, 1.1–10.8, p = 0.03) and pancreas allograft failure (HR 2.26, 1.0–4.8, p = 0.01). Conclusions: A MAP > 91 mmHg at the time point of reperfusion was associated with a reduced rate of postoperative complications, enhancing and recovering long-term graft function and outcome and thus increasing long-term survival in SPKT recipients.

Deviations from PRx-derived optimal blood pressure are associated with mortality after cardiac arrest

AimPressure reactivity index (PRx) provides a surrogate measurement of cerebrovascular autoregulation (CAR). We determined whether deviations from PRx-derived optimal mean arterial pressure (MAPopt) were associated with in-hospital mortality after adult cardiac arrest. MethodsRetrospective analysis of post-cardiac arrest patients who had continuously recorded intracranial pressure (ICP) and MAP. PRx was calculated as a moving, linear correlation between ICP and MAP. Impaired CAR was defined as PRx ≥ 0.3. MAPopt was calculated using a multi-window weighted algorithm. The burdens of MAP < 5 mmHg below MAPopt (MAPopt-5) and > 5 mmHg above MAPopt (MAPopt + 5) were calculated by integrating the area between MAP and MAPopt-5 or MAPopt + 5 curves, respectively. Univariate logistic regression tested the association between burden of MAP < MAPopt-5 and outcome. ResultsTwenty-two patients were analyzed. Thirteen (59%) patients died before hospital discharge. Time (median [IQR]) between ROSC and monitoring initiation was 16 [14, 21] hours and duration of monitoring was 35 [22, 48] hours; neither differed between survivors and non-survivors. Median MAPopt was 89 [85, 97] mmHg and did not differ between survivors and non-survivors (89 [83, 94] vs. 91 [85, 105] mmHg, p = 0.64). Burden of MAP < MAPopt–5 was greater for non-survivors compared to survivors (OR 3.6 [95% CI 1.2–15.6]). Range of intact CAR (upper-lower limit) was narrower for non-survivors when compared to survivors (5 [0, 22] vs. 24 [7, 36] mmHg, p = 0.03). ConclusionA greater burden of MAP below PRx-derived MAPopt-5 was associated with mortality after cardiac arrest. Non-survivors had a narrower range of intact CAR than survivors.

Low Blood Pressure Threshold for Adverse Outcomes During Left Ventricular Assist Device Support

It has been suggested that maintaining low mean arterial pressure (MAP) in left ventricular assist device (LVAD) recipients is associated with a reduced risk of stroke/death. However, the lower limit of the optimal MAP range has not been established. We aimed to identify this lower limit in a contemporary cohort of LVAD recipients with frequent longitudinal MAP measurements. We analyzed 86,651 MAP measurements in 309 patients with an LVAD (32% LVADs with full magnetic levitation of the impeller) at a tertiary medical center during a mean follow-up of 1.7 ± 1.1years. Cox proportional hazards regression modeling was used to study the association of serial MAP measurements with stroke/death within 3years after index discharge. Multivariate analysis identified MAP ≤75mmHg, compared with MAP >75mmHg, as the low MAP threshold associated with increased risk of death (hazard ratio [HR] 4.74, 95% confidence interval [CI] 2.85 to 7.87, p<0.001), stroke (HR 2.72;, 95% CI 1.39 to 5.33, p=0.01), and stroke/death (HR 4.45, 95% CI 2.83 to 6.99, p<0.001). The risk associated with MAP ≤75mmHg was consistent in subgroups categorized by age, gender, race, device type, renal function, right-sided heart failure, and blood pressure medications. In conclusion, our findings suggest that maintaining MAP ≤75mmHg during long-term follow-up in LVAD recipients is associated with increased risk of stroke/death regardless of risk factors or medical management.

Optimal Mean Arterial Pressure for Favorable Neurological Outcomes in Survivors after Extracorporeal Cardiopulmonary Resuscitation.

We evaluated the optimal mean arterial pressure (MAP) for favorable neurological outcomes in patients who underwent extracorporeal cardiopulmonary resuscitation (ECPR). Adult patients who underwent ECPR were included. The average MAP was obtained during 6, 12, 24, 48, 72, and 96 h after cardiac arrest, respectively. Primary outcome was neurological status upon discharge, as assessed by the Cerebral Performance Categories (CPC) scale (range from 1 to 5). Overall, patients with favorable neurological outcomes (CPC 1 or 2) tended to have a higher average MAP than those with poor neurological outcomes. Six models were established based on ensemble algorithms for machine learning, multiple logistic regression and observation times. Patients with average MAP around 75 mmHg had the least probability of poor neurologic outcomes in all the models. However, those with average MAPs below 60 mmHg had a high probability of poor neurological outcomes. In addition, based on an increase in the average MAP, the risk of poor neurological outcomes tended to increase in patients with an average MAP above 75 mmHg. In this study, average MAPs were associated with neurological outcomes in patients who underwent ECPR. Especially, maintaining the survivor’s MAP at about 75 mmHg may be important for neurological recovery after ECPR.