The Relationship Between Carotid Artery Stenosis and the Development of Open-Angle Glaucoma: A Long-term Cohort Study in Taiwan.

PURPOSES: To determine the relationship between carotid artery stenosis (CAS) and the development of open-angle glaucoma (OAG) in the Taiwanese population. METHODS: This retrospective cohort study was conducted using Chang Gung Research Database. Cox-proportional hazards model was applied to calculate the hazard ratio for OAG between CAS and the control cohort. RESULTS: Among 19,590 CAS patients, 17,238 had mild CAS (<50%), 1,895 had moderate CAS (50-69%), and 457 had severe CAS (≥70%). The CAS cohort had a higher proportion of several comorbidities. After adjusting for comorbidities, no significant difference in OAG development was found between CAS and control cohorts. Matching for key comorbidities, no significant differences in OAG incidence were found between matched cohorts (P = .869). Subdividing the matched CAS cohort by stenosis severity: mild (<50%), moderate (50-69%), and severe (≥70%), a statistically significantly lower OAG risk was observed in patients with mild CAS stenosis (HR: 1.12, 95% CI = 1.03-1.21, P = .006). Kaplan-Meier analysis revealed reduced OAG incidence in CAS patients who underwent surgical intervention, compared to the control cohort (P <.001). Subgroup analysis revealed that patients in the mild CAS stenosis group, those who underwent surgical intervention exhibited a reduced OAG risk (HR: 0.29, 95% CI = 0.15-0.58, P = .001). CONCLUSIONS: No statistically significant differences in OAG risk were observed between patients with CAS and the control cohort. The severity of CAS appears to influence OAG risk, with surgical intervention potentially offering protective effects, particularly in patients with mild CAS stenosis (<50%), suggesting that enhanced ocular perfusion post-surgery may act as a protective factor against OAG development.

Comparing reactive versus empiric cerebrospinal fluid drainage strategies for spinal perfusion pressure optimization in patients with acute traumatic spinal cord injuries.

BACKGROUND: Spinal cord hypoperfusion undermines clinical recovery in acute traumatic spinal cord injuries. New guidelines suggest cerebrospinal fluid (CSF) drainage is an important strategy for preventing spinal cord hypoperfusion in the acute post-injury phase. METHODS: This study included participants presenting to a single level 1 trauma center between 2018 and 2022 with cervical or thoracic traumatic spinal cord injury severity grade A-C, as evaluated by the American spinal injury association impairment scale (AIS). The primary objective of this study was to compare the efficacy of two CSF drainage protocols in preventing spinal cord hypoperfusion; 1) draining CSF only when spinal cord perfusion pressure (SCPP) drops below 65 mmHg (i.e. reactive) versus 2) empiric CSF drainage of 5-10 mL every hour. Intrathecal pressure, spinal cord perfusion pressure (SCPP), mean arterial pressure (MAP), and vasopressor utilization were compared using univariate T-test statistical analysis. RESULTS: While there was no difference in the incidence of sub-optimal SCPP (<65 mmHg; p = 0.1658), reactively drained participants were more likely to exhibit critical hypoperfusion (<50 mmHg; p = 0.0030) despite also having lower average intrathecal pressures (p < 0.001). There were no differences in average SCPP, mean arterial pressure (MAP), or vasopressor utilization between the two groups (p > 0.05). CONCLUSIONS: Empiric (vs reactive) CSF drainage resulted in fewer incidences of critical spinal cord hypoperfusion for patients with acute traumatic spinal cord injuries.

Optimization of kidney function in cardiac surgery patients with intra-abdominal hypertension: expert opinion.

Cardiac surgery-associated acute kidney injury (CSA-AKI) affects up to 42% of cardiac surgery patients. CSA-AKI is multifactorial, with low abdominal perfusion pressure often overlooked. Abdominal perfusion pressure is calculated as mean arterial pressure minus intra-abdominal pressure (IAP). IAH decreases cardiac output and compresses the renal vasculature and renal parenchyma. Recent studies have highlighted the frequent occurrence of IAH in cardiac surgery patients and have linked the role of low perfusion pressure to the occurrence of AKI. This review and expert opinion illustrate current evidence on the pathophysiology, diagnosis, and therapy of IAH and ACS in the context of AKI.

Distal Bypass Improves Skin Perfusion Pressure at the Whole Foot Regardless of Angiosomes in Patients with Chronic Limb-Threatening Ischemia.

Objectives: Distal bypass surgery's effect on tissue blood pressure beyond a focal angiosome remains debated. This study assessed tissue blood pressure in both direct revascularized angiosome (DRA) and indirect revascularized angiosome (IRA) after bypass surgery, utilizing repeated skin perfusion pressure (SPP) measurements. Methods: Twenty-nine limbs in 27 chronic limb-threatening ischemia (CLTI) patients (22 males and five females, age: 70.2 ± 9.3 years) who received distal bypass surgery were enrolled. SPP measurements were conducted for the DRA and IRA at 10 time intervals, encompassing both preoperative and postoperative periods of every 3-5 days until 30 days. Results: In total, 486 SPP measurements were collected from 58 measurement sites, and the transition of the SPP at the DRA was 35.4-62.5-59.5-70.2-58.2-62.2-63.1-63.6-63.8-73.4 mmHg and IRA was 29.4-53.4-53.7-58.8-51.3-63.1-47.9-62.1-57.6-61.0 mmHg. No significant differences were observed between SPP at the DRA and IRA. Fifteen wounds on the DRA (63%) and five on the IRA (100%) healed. Conclusion: Distal bypass improves SPP in both direct and IRAs of CLTI patients. These data indicated distal bypass improves tissue blood flow at entire foot regardless of angiosomes.

Reduced uterine perfusion pressure as a model for preeclampsia and fetal growth restriction in murine: a systematic review and meta-analysis.

The reduced uterine perfusion pressure (RUPP) model is frequently used to study preeclampsia and fetal growth restriction. An improved understanding of influential factors might improve reproducibility and reduce animal use considering the variability in RUPP phenotype. We performed a systematic review and meta-analysis by searching Medline and Embase (until 28 March, 2023) for RUPP studies in murine. Primary outcomes included maternal blood pressure (BP) or proteinuria, fetal weight or crown-rump length, fetal reabsorptions, or antiangiogenic factors. We aimed to identify influential factors by meta-regression analysis. We included 155 studies. Our meta-analysis showed that the RUPP procedure results in significantly higher BP (MD = 24.1 mmHg; [22.6; 25.7]; n = 148), proteinuria (SMD = 2.3; [0.9; 3.8]; n = 28), fetal reabsorptions (MD = 50.4%; [45.5; 55.2]; n = 42), circulating soluble FMS-like tyrosine kinase-1 (sFlt-1) (SMD = 2.6; [1.7; 3.4]; n = 34), and lower fetal weight (MD = -0.4 g; [-0.47; -0.34]; n = 113. The heterogeneity (variability between studies) in primary outcomes appeared ≥90%. Our meta-regression identified influential factors in the method and time point of BP measurement, randomization in fetal weight, and type of control group in sFlt-1. The RUPP is a robust model considering the evident differences in maternal and fetal outcomes. The high heterogeneity reflects the observed variability in phenotype. Because of underreporting, we observed reporting bias and a high risk of bias. We recommend standardizing study design by optimal time point and method chosen for readout measures to limit the variability. This contributes to improved reproducibility and thereby eventually improves the translational value of the RUPP model.

Periods of low renal perfusion pressure are associated with acute kidney injury following paediatric cardiac surgery.

INTRODUCTION: Acute kidney injury is associated with worse outcomes after cardiac surgery. The haemodynamic goals to ameliorate kidney injury are not clear. Low post-operative renal perfusion pressure has been associated with acute kidney injury in adults. Inadequate oxygen delivery may also cause kidney injury. This study evaluates pressure and oximetric haemodynamics after paediatric cardiac surgery and their association with acute kidney injury. MATERIALS AND METHODS: Retrospective case-control study at a children's hospital. Patients were < 6 months of age who underwent a Society of Thoracic Surgery-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery categories ≥ 3. Low renal perfusion pressure was time and depth below several tested thresholds. The primary outcome was serum creatine-defined acute kidney injury in the first 7 days. RESULTS: Sixty-six patients (median age 8 days) were included. Acute kidney injury occurred in 36%. The time and depth of renal perfusion pressure < 42 mmHg in the first 24 hours was greater in acute kidney injury patients (94 versus 35 mmHg*minutes of low renal perfusion pressure/hour, p = 0.008). In the multivariable model, renal perfusion pressure < 42 mmHg was associated with acute kidney injury (aOR: 2.07, 95%CI: 1.25-3.82, p = 0.009). Mean arterial pressure, central venous pressure, and measures of inadequate oxygen delivery were not associated with acute kidney injury. CONCLUSION: Periods of low renal perfusion pressure (<42 mmHg) in the first 24 post-operative hours are associated with acute kidney injury. Renal perfusion pressure is a potential modifiable target that may mitigate the impact of acute kidney injury after paediatric cardiac surgery.

Should we perform decompressive laparotomy during severe acute pancreatitis with intra-abdominal hypertension below 25 mmHg: Only the gut knows.

We suggest that during severe acute pancreatitis (SAP) with intra-abdominal hypertension, practitioners should consider decompressive laparotomy, even with intra-abdominal pressure (IAP) below 25 mmHg. Indeed, in this setting, non-occlusive mesenteric ischemia (NOMI) may occur even with IAP below this cutoff and lead to transmural necrosis if abdominal perfusion pressure is not promptly restored. We report our experience of 18 critically ill patients with SAP having undergone decompressive laparotomy of which one third had NOMI while IAP was mostly below 25 mmHg.

Preliminary Study on Application of Combined Monitoring of Neuroelectrophysiology-Intracranial Pressure-Cerebral Perfusion Pressure in Craniotomy for Intracranial Aneurysm Clipping: An Anatomical and Clinical Study

SUMMARY: Intracranial aneurysm is a common cerebrovascular disease with high mortality. Neurosurgical clipping for the treatment of intracranial aneurysms can easily lead to serious postoperative complications. Studies have shown that intraoperative monitoring of the degree of cerebral ischemia is extremely important to ensure the safety of operation and improve the prognosis of patients. Aim of this study was to probe the application value of combined monitoring of intraoperative neurophysiological monitoring (IONM)-intracranial pressure (ICP)-cerebral perfusion pressure (CPP) in craniotomy clipping of intracranial aneurysms. From January 2020 to December 2022, 126 patients in our hospital with intracranial aneurysms who underwent neurosurgical clipping were randomly divided into two groups. One group received IONM monitoring during neurosurgical clipping (control group, n=63), and the other group received IONM-ICP-CPP monitoring during neurosurgical clipping (monitoring group, n=63). The aneurysm clipping and new neurological deficits at 1 day after operation were compared between the two groups. Glasgow coma scale (GCS) score and national institutes of health stroke scale (NIHSS) score were compared before operation, at 1 day and 3 months after operation. Glasgow outcome scale (GOS) and modified Rankin scale (mRS) were compared at 3 months after operation. All aneurysms were clipped completely. Rate of new neurological deficit at 1 day after operation in monitoring group was 3.17 % (2/63), which was markedly lower than that in control group of 11.11 % (7/30) (P0.05). Combined monitoring of IONM-ICP-CPP can monitor the cerebral blood flow of patients in real time during neurosurgical clipping, according to the monitoring results, timely intervention measures can improve the consciousness state of patients in early postoperative period and reduce the occurrence of early postoperative neurological deficits.

El aneurisma intracraneal es una enfermedad cerebrovascular común con alta mortalidad. El clipaje neuroquirúrgico para el tratamiento de aneurismas intracraneales puede provocar complicaciones posoperatorias graves. Los estudios han demostrado que la monitorización intraoperatoria del grado de isquemia cerebral es extremadamente importante para garantizar la seguridad de la operación y mejorar el pronóstico de los pacientes. El objetivo de este estudio fue probar el valor de la aplicación de la monitorización combinada de la monitorización neurofisiológica intraoperatoria (IONM), la presión intracraneal (PIC) y la presión de perfusión cerebral (CPP) en el clipaje de craneotomía de aneurismas intracraneales. Desde enero de 2020 hasta diciembre de 2022, 126 pacientes de nuestro hospital con aneurismas intracraneales que se sometieron a clipaje neuroquirúrgico se dividieron aleatoriamente en dos grupos. Un grupo recibió monitorización IONM durante el clipaje neuroquirúrgico (grupo de control, n=63) y el otro grupo recibió monitorización IONM-ICP-CPP durante el clipaje neuroquirúrgico (grupo de monitorización, n=63). Se compararon entre los dos grupos el recorte del aneurisma y los nuevos déficits neurológicos un día después de la operación. La puntuación de la escala de coma de Glasgow (GCS) y la puntuación de la escala de accidentes cerebrovasculares de los institutos nacionales de salud (NIHSS) se compararon antes de la operación, 1 día y 3 meses después de la operación. La escala de resultados de Glasgow (GOS) y la escala de Rankin modificada (mRS) se compararon 3 meses después de la operación. Todos los aneurismas fueron cortados por completo. La tasa de nuevo déficit neurológico 1 día después de la operación en el grupo de seguimiento fue del 3,17 % (2/63), que fue notablemente inferior a la del grupo de control del 11,11 % (7/30) (P 0,05). La monitorización combinada de IONM-ICP-CPP puede controlar el flujo sanguíneo cerebral de los pacientes en tiempo real durante el corte neuroquirúrgico; de acuerdo con los resultados de la monitorización, las medidas de intervención oportunas pueden mejorar el estado de conciencia de los pacientes en el período postoperatorio temprano y reducir la aparición de problemas postoperatorios tempranos y déficits neurológicos.

Should Patients with Traumatic Brain Injury with Significant Contusions be Treated with Different Neurointensive Care Targets?

BACKGROUND: Patients with traumatic brain injury (TBI) with large contusions make up a specific TBI subtype. Because of the risk of brain edema worsening, elevated cerebral perfusion pressure (CPP) may be particularly dangerous. The pressure reactivity index (PRx) and optimal cerebral perfusion pressure (CPPopt) are new promising perfusion targets based on cerebral autoregulation, but they reflect the global brain state and may be less valid in patients with predominant focal lesions. In this study, we aimed to investigate if patients with TBI with significant contusions exhibited a different association between PRx, CPP, and CPPopt in relation to functional outcome compared to those with small/no contusions. METHODS: This observational study included 385 patients with moderate to severe TBI treated at a neurointensive care unit in Uppsala, Sweden. The patients were classified into two groups: (1) significant contusions (> 10 mL) and (2) small/no contusions (but with extra-axial or diffuse injuries). The percentage of good monitoring time (%GMT) with intracranial pressure > 20 mm Hg; PRx > 0.30; CPP < 60 mm Hg, within 60-70 mm Hg, or > 70 mm Hg; and ΔCPPopt less than - 5 mm Hg, ± 5 mm Hg, or > 5 mm Hg was calculated. Outcome (Glasgow Outcome Scale-Extended) was assessed after 6 months. RESULTS: Among the 120 (31%) patients with significant contusions, a lower %GMT with CPP between 60 and 70 mm Hg was independently associated with unfavorable outcome. The %GMTs with PRx and ΔCPPopt ± 5 mm Hg were not independently associated with outcome. Among the 265 (69%) patients with small/no contusions, a higher %GMT of PRx > 0.30 and a lower %GMT of ΔCPPopt ± 5 mm Hg were independently associated with unfavorable outcome. CONCLUSIONS: In patients with TBI with significant contusions, CPP within 60-70 mm Hg may improve outcome. PRx and CPPopt, which reflect global cerebral pressure autoregulation, may be useful in patients with TBI without significant focal brain lesions but seem less valid for those with large contusions. However, this was an observational, hypothesis-generating study; our findings need to be validated in prospective studies before translating them into clinical practice.

Monitoring of cerebral blood flow autoregulation: physiologic basis, measurement, and clinical implications.

Cerebral blood flow (CBF) autoregulation is the physiologic process whereby blood supply to the brain is kept constant over a range of cerebral perfusion pressures ensuring a constant supply of metabolic substrate. Clinical methods for monitoring CBF autoregulation were first developed for neurocritically ill patients and have been extended to surgical patients. These methods are based on measuring the relationship between cerebral perfusion pressure and surrogates of CBF or cerebral blood volume (CBV) at low frequencies (<0.05 Hz) of autoregulation using time or frequency domain analyses. Initially intracranial pressure monitoring or transcranial Doppler assessment of CBF velocity was utilised relative to changes in cerebral perfusion pressure or mean arterial pressure. A more clinically practical approach utilising filtered signals from near infrared spectroscopy monitors as an estimate of CBF has been validated. In contrast to the traditional teaching that 50 mm Hg is the autoregulation threshold, these investigations have found wide interindividual variability of the lower limit of autoregulation ranging from 40 to 90 mm Hg in adults and 20-55 mm Hg in children. Observational data have linked impaired CBF autoregulation metrics to adverse outcomes in patients with traumatic brain injury, ischaemic stroke, subarachnoid haemorrhage, intracerebral haemorrhage, and in surgical patients. CBF autoregulation monitoring has been described in both cardiac and noncardiac surgery. Data from a single-centre randomised study in adults found that targeting arterial pressure during cardiopulmonary bypass to above the lower limit of autoregulation led to a reduction of postoperative delirium and improved memory 1 month after surgery compared with usual care. Together, the growing body of evidence suggests that monitoring CBF autoregulation provides prognostic information on eventual patient outcomes and offers potential for therapeutic intervention. For surgical patients, personalised blood pressure management based on CBF autoregulation data holds promise as a strategy to improve patient neurocognitive outcomes.

Evaluation of Cerebral Perfusion Pressure, Cerebral Blood Flow, and Cerebral Oxygenation at Different Head of Bed Positions Using Transcranial Doppler and Near-Infrared Spectroscopy in Postoperative Neurosurgical Patients.

OBJECTIVES: Nursing postoperative neurosurgical patients with head of bed (HOB) elevation beyond 30° might be desired at times to prevent pulmonary complications. Due to the paucity of studies determining the effect of HOB beyond 30° on cerebral perfusion pressure (CPP), cerebral blood flow (CBF), and regional cerebral oxygenation (rSO2), this study was designed. METHODS: A total of 40 patients following elective neurosurgery for supratentorial tumors were studied in the neurosurgical intensive care unit three hours following admission. They were assessed for CBF velocities of middle cerebral arteries on either side using transcranial color Doppler (TCCD), rSO2 using near-infrared spectroscopy (NIRS), and mean arterial pressure measured at tragus level at various HOB positions. The estimated cerebral perfusion pressure (CPPe) was calculated from TCCD parameters, and the estimated intracranial pressure (ICPe) was then derived. Their variations at different HOB positions were noted. RESULTS: TCCD parameters such as peak systolic velocity (PSV) and mean flow velocity (MFV) did not significantly vary upon elevating HOB from 0° to 30° but reduced significantly when HOB was further elevated to 60° (p < 0.05). ICPe reduced significantly with a change of HOB positions from 0° to 60° (p < 0.001), and a significant reduction in CPPe was noticed when HOB was elevated to 60° (67.2 ± 10.1 mmHg vs. 74.7 ± 11.2 mmHg at 0°). However, none of these HOB positions affected rSO2 values. CONCLUSION: Postoperative nursing with positions up to 60° HOB can be tried in indicated patients following elective neurosurgery when complemented with CBF velocity and rSO2 monitoring and in whom CPP-guided therapy is not preferred.

MicroRNA-195-5p Attenuates Pregnancy-Induced Hypertension by Inhibiting Oxidative Stress via OTX1/MAPK Signaling Pathway.

Pregnancy-induced hypertension (PIH) is a hypertensive disorder during pregnancy and can induce perinatal death of human infants. MicroRNA (miR)-195-5p was validated to display low expression in severe preeclampsia placentas, but the role of miR-195-5p in pregnancy-induced hypertension (PIH) has not been investigated. The study emphasized on the functions and mechanism of miR-195-5p in PIH. A reduced uterine perfusion pressure (RUPP) rat model was established to mimic PIH in vivo. Adenovirus (Ad)-miR-195-5p agomir and/or Ad-OTX1 were further injected into some model rats. RT-qPCR was conducted to assess the expression of miR-195-5p and orthodenticle homeobox 1 (OTX1) in rat placental tissues, the isolated aortic endothelial cells (AECs), and in serum samples of PIH patients. Western blot analysis was implemented to measure the protein levels of OTX1, VEGFA, and key factors involved in the MAPK signaling pathway. The concentrations of oxidative stress markers (superoxide dismutase, catalase, and lipid hydroperoxide) in AECs and placental tissues of RUPP rats were measured by corresponding kits. The binding relation between miR-195-5p and OTX1 was verified using the dual-luciferase reporter assay. Hematoxylin-eosin staining was conducted to evaluate the pathological features of rat placental tissues. MiR-195-5p was downregulated, while OTX1 was upregulated in rat placental tissues and human serum samples of PIH patients. MiR-195-5p could target OTX1 and inversely regulate OTX1 expression in AECs and rat placental tissues. In addition, miR-195-5p can negatively regulate VEGFA level. Furthermore, miR-195-5p inactivates oxidative stress and the MAPK signaling by downregulating OTX1 in AECs. In vivo experiments revealed that OTX1 overexpression reversed the protective effect of miR-195-5p overexpression on placental damage and oxidative stress. MiR-195-5p alleviates PIH by inhibiting oxidative stress via targeting OTX1 and inactivating MAPK signaling.

Oxygen Saturation or Tissue Oxygen Determinations on Skin Whose Viability is at Risk.

The triad of ischaemia, neuropathy, and infection are among the principal causes of lower extremity wounds that are commonly prevalent in patients with diabetic foot (DF) a condition in which peripheral arterial disease commonly co-exists. The prevalence of this condition is increasing globally and with it, the mounting costs of its management. One aspect of management is saving limbs and or digits, a crucial part of this process is assessing tissue viability of skin which is a focus of this review: there are other aspects which are well described in the literature. Amputations are offered to limit the damage resulting from acute/chronic ischaemia. Holstein measured skin perfusion pressure using a radioisotope clearance technique to describe critically ischaemic skin; he found 30 mm Hg as the threshold above which healing may reliably be expected. Recent advances in vascular surgery and related technology have informed evidence-based advice to revascularize and save limbs; in practice, this may leave a wound in the distal skin unhealed; managing these raises questions of tissue viability. Much effort has been made to manage, prevent and to better understand these lower extremity wounds using measurements of tissue oxygen, oxygen saturation and skin imaging. The measurement techniques and their relevant merits are examined in this article. Advances in wound management systems and protocols can also facilitate the repair processes, and those which can have a particular impact on restoring or maintaining tissue perfusion are also discussed in the article.

Assessment of Individualized Mean Perfusion Pressure Targets for the Prevention of Cardiac Surgery-Associated Acute Kidney Injury-The PrevHemAKI Randomized Controlled Trial.

BACKGROUND: Retrospective studies support that mean perfusion pressure (MPP) deficit in cardiac surgery patients is associated with a higher incidence of acute kidney injury (CS-AKI). The aim of our study was to apply an algorithm based on MPP in the postoperative period to determine whether management with an individualized target reduces the incidence of CS-AKI. METHODS: Randomized controlled trial of patients undergoing cardiac surgery with extracorporeal circulation. Adult patients submitted to valve replacement and/or bypass surgery with a high risk of CS-AKI evaluated by a Leicester score >30 were randomized to follow a target MPP of >75% of the calculated baseline or a standard hemodynamic management during the first postoperative 24 h. RESULTS: Ninety-eight patients with an eGFR of 54 mL/min were included. There were no differences in MAP and MPP in the first 24 h between the randomized groups, although a higher use of noradrenaline was found in the intervention arm (38.78 vs. 63.27, p = 0.026). The percentage of time with MPP < 75% of measured baseline was similar in both groups (10 vs. 12.7%, p = 0.811). MAP during surgery was higher in the intervention group (73 vs. 77 mmHg, p = 0.008). The global incidence of CS-AKI was 36.7%, being 38.6% in the intervention group and 34.6% in the control group (p = 0.40). There were no differences in extrarenal complications between groups as well. CONCLUSION: An individualized hemodynamic management based on MPP compared to standard treatment in cardiac surgery patients was safe but did not reduce the incidence of CS-AKI in our study.

Cerebral hemodynamic effects of head-up CPR in a porcine model.

AIM: To assess the hemodynamic effects of head elevation on cerebral perfusion during cardiopulmonary resuscitation (CPR) in a porcine model of cardiac arrest. METHODS: VF was induced in eight 65 kg pigs that were treated with CPR after five minutes of no flow. Mean arterial pressure (MAP) was measured at the descending thoracic aorta. Internal carotid artery blood flow (CBF) was measured with an ultrasound probe. Cerebral perfusion pressure (CerPP) was calculated in two ways (CerPPICAP and CerPPreported) using the same intracranial pressure (ICP) measurement. CePPreported was calculated as MAP-ICP. CerPPICAP was calculated by using intracranial arterial pressure (ICAP) - ICP. The animals were switched between head up (HUP) and supine (SUP) CPR every five minutes for a total of twenty minutes of resuscitation. RESULTS: MAP and coronary perfusion pressure measurements were similar in both CPR positions (p = 0.36 and p = 0.1, respectively). ICP was significantly lower in the HUP CPR group (14.7 ± 1 mm Hg vs 26.9 ± 1 mm Hg, p < 0.001) as was ICAP (30.1 ± 2 mm Hg vs 42.6 ± 1 mmHg, p < 0.001). The proportional decrease in ICP and ICAP resulted in similar CerPPICAP comparing HUP and SUPCPR (p = 0.7). CBF was significantly lower during HUPCPR when compared to SUPCPR (58.5 ± 3 ml/min vs 78 ± 4 ml/min, p < 0.001). A higher CerPPreported was found during the HUP compared to SUP-CPR, when MAP was used (36.6 ± 2 mm Hg vs 23 ± 2 mm Hg, p < 0.001) without correcting for the hydrostatic pressure drop. CONCLUSION: HUP did not affect cerebral perfusion pressure and it significantly decreased internal carotid blood flow.

Dilemmas of Adopting Goal-Directed Perfusion in Extracorporeal Circulation: A Narrative Review.

OBJECTIVE: Extracorporeal circulation (ECC) is generally based on standards established in the last decade. In recent years, a concept of perfusion management during ECC, goal-directed perfusion (GDP), has emerged to create optimal conditions for oxygen delivery and extraction, initiated by Rannuci et al. The aim of the present work was to determine whether the ECC procedure can truly be optimized with the current state of knowledge and understanding of human physiology. METHODS: Discussed articles from 2017 to 2022 were selected from the MEDLINE (PubMed) database using the keywords "cardiopulmonary bypass" AND "cardiac surgery" AND "oxygen delivery" with the conditions of "clinical trial" OR "randomized controlled trial." RESULTS: The concept of GDP is an attempt to reproduce the physiological conditions of tissue respiration during ECC. Published articles, also due to their retrospective nature, are based on standards and recommendations that do not fully fit the field of physiological circulation. There are still insufficient tools to assess the relationship between volemia, perfusion pressure, and pump performance. Limitations include indications for vasoactive drugs. Methodology has rarely taken into account the period of starting and stopping the heart-lung machine, the most pronounced periods of circulatory destabilization with reduced oxygen delivery. CONCLUSIONS: Problems associated with ECC such as acute kidney injury, liver failure, vasoplegic syndrome, and others must await its resolution. The use of advanced monitoring technology and data engineering may allow the development of baseline hemodynamic models, which may make the ECC procedure more physiologic and thus improve the safety of the procedure.

Effects of pneumoperitoneum and Trendelenburg position on intracranial pressure and cerebral blood flow assessed using transcranial doppler: A prospective observational study.

Background and Aims: Laparoscopic lower abdominal surgeries involve carbon dioxide (CO2) insufflation and Trendelenburg position. The raised intra-abdominal pressure can increase intracranial pressure (ICP) and alter cerebral blood flow. This study was conducted to determine the effect of pneumoperitoneum and Trendelenburg position on ICP and cerebral perfusion pressure (CPP) measured using transcranial Doppler (TCD). Material and Methods: A prospective observational study was conducted in 43 patients of either sex, aged between 18 and 60 years with American Society of Anesthesiologists physical status I and II, undergoing elective laparoscopic surgery in Trendelenburg position. After standard anesthesia induction, pneumoperitoneum was created to facilitate surgery, maintaining an intra-abdominal pressure of 10-15 mmHg and Trendelenburg position of 25°-30°. End-tidal carbon dioxide (EtCO2) was maintained between 30 and 35 mmHg. The ICP was assessed non-invasively using TCD-based diastolic flow velocities (FVd) and pulsatility index (PI) of middle cerebral artery. Data was represented as mean ± standard deviation and compared using paired t test. A P value of < 0.05 was considered significant. Results: Mean ICPPI at baseline was 14.02 ± 0.89 mmHg which increased to 14.54 ± 1.21 mmHg at pneumoperitoneum and Trendelenburg position (P = 0.005). Mean ICPFVd at baseline was 6.25 ± 2.47 mmHg which increased to 8.64 ± 3.79 mmHg at pneumoperitoneum and Trendelenburg position (P < 0.001). There was no statistically significant change in the CPP or mean arterial pressure values intraoperatively. Conclusions: Laparoscopic procedures with CO2 pneumoperitoneum in Trendelenburg position increase ICP as measured using TCD ultrasonography. The CPP was not significantly altered when EtCO2 was maintained in the range of 30-35 mmHg.

Intraoperative blood pressure: could less be more?

Retrospective observational studies have reported a significant association between intraoperative hypotension and postoperative morbidity. However, association does not imply causation, and whether preventing intraoperative hypotension can improve patient outcome remains to be demonstrated. In this issue of the British Journal of Anaesthesia, D'Amico and colleagues meta-analysed 10 prospective randomised trials comparing low (≤60 mm Hg) and higher mean arterial pressure targets during anaesthesia and surgery. They did not observe an increase in postoperative morbidity and mortality in the low target group. In contrast, they reported a statistically significant (but not clinically relevant) reduction in postoperative cardiac arrhythmia and hospital length of stay when targeting mean arterial pressure ≤60 mm Hg. These findings suggest that during most surgical cases, intraoperative hypotension is a marker of the severity, frailty, or both rather than a mediator of postoperative complications.

Feasibility of continuous intra-uterine pressure measurements during amnioreduction in twin-to-twin transfusion syndrome therapy.

INTRODUCTION: This work explores the feasibility of simultaneous and continuous intra-abdominal, intra-uterine, and arterial blood pressure measurements to examine the hemodynamic perturbation expected during therapeutic amnioreduction and to better understand the protective role of the placenta during that treatment. METHODS: Patients with twin-to-twin transfusion syndrome were treated with fetoscopic laser ablation followed by amnioreduction. Intra-abdominal, intra-uterine, and mean arterial pressures were simultaneously recorded during amnioreduction performed in steps of 200 mL. Placental thickness and uterine dimensions were measured before and after amnioreduction by ultrasonography. RESULTS: Useful pressure recordings were obtained between volume reduction steps and short hands-off periods in four studies. Median amnioreduction volume was 1400 mL corresponding to a median uterine volume reduction of 1121 mL. Mean intra-uterine pressure significantly fell from 24.8 to 13.6 mmHg (p = 0.011) and intra-abdominal pressure significantly decreased from 13.4 to 9.2 mmHg after amnioreduction (p = 0.015). Uterine pressure recordings revealed transient contractions (A, in mmHg) following individual amnioreduction steps, which increased with fractional amnioreduction (F, no dimension) (A = 17.23*F + 11.81; r = 0.50, p = 0.001). DISCUSSION: Simultaneous and continuous measurement of intra-abdominal, intra-uterine, and arterial blood pressures during amnioreduction is feasible. The dynamics reveal transient uterine contractions reaching levels comparable to those seen during childbirth which seem to oppose impending maternal hypovolemia by placental steal at the expense of temporarily reducing placental perfusion pressure and underline the importance of uterine and placental interaction.

Intracranial lesion features in moderate-to-severe traumatic brain injury: relation to neurointensive care variables and clinical outcome.

BACKGROUND: The primary aim was to determine the association of intracranial hemorrhage lesion type, size, mass effect, and evolution with the clinical course during neurointensive care and long-term outcome after traumatic brain injury (TBI). METHODS: In this observational, retrospective study, 385 TBI patients treated at the neurointensive care unit at Uppsala University Hospital, Sweden, were included. The lesion type, size, mass effect, and evolution (progression on the follow-up CT) were assessed and analyzed in relation to the percentage of secondary insults with intracranial pressure > 20 mmHg, cerebral perfusion pressure < 60 mmHg, and cerebral pressure autoregulatory status (PRx) and in relation to Glasgow Outcome Scale-Extended. RESULTS: A larger epidural hematoma (p < 0.05) and acute subdural hematoma (p < 0.001) volume, greater midline shift (p < 0.001), and compressed basal cisterns (p < 0.001) correlated with craniotomy surgery. In multiple regressions, presence of traumatic subarachnoid hemorrhage (p < 0.001) and intracranial hemorrhage progression on the follow-up CT (p < 0.01) were associated with more intracranial pressure-insults above 20 mmHg. In similar regressions, obliterated basal cisterns (p < 0.001) were independently associated with higher PRx. In a multiple regression, greater acute subdural hematoma (p < 0.05) and contusion (p < 0.05) volume, presence of traumatic subarachnoid hemorrhage (p < 0.01), and obliterated basal cisterns (p < 0.01) were independently associated with a lower rate of favorable outcome. CONCLUSIONS: The intracranial lesion type, size, mass effect, and evolution were associated with the clinical course, cerebral pathophysiology, and outcome following TBI. Future efforts should integrate such granular data into more sophisticated machine learning models to aid the clinician to better anticipate emerging secondary insults and to predict clinical outcome.