Heterogeneous impact of hypotension on organ perfusion and outcomes: a narrative review

Nadir heart rate as a novel risk marker of postoperative complications - A propensity matched analysis

AIM

Although vital signs have a well-described 24-h cyclic variation (circadian rhythm), this variation is often not considered in clinical vital sign monitoring despite being influenced by physiologic stress from complications. This study aimed to evaluate the lowest heart rate at night (night-nadir) (NN-HR) as a novel risk marker for serious adverse events (SAE) in postoperative patients, rather than the average nocturnal heart rate.

METHODS

This was a propensity-matched nested case-control study of continuously monitored vital sign data (heart rate (HR), respiration rate, oxygen saturation and blood pressure) for up to 5 days after major non-cardiac surgery. The primary outcome was any SAE that occurred up to 24 h after a circadian value calculation. We compared NN-HR between patients who developed SAE and those who did not during similar postoperative periods.

RESULTS

Out of 588 patients, 104 (17.8 %) experienced an SAE during the monitored period and were matched with a median of 201 controls. The NN-HR was significantly higher in patients with impending SAE (median 74.0 bpm [IQR 68.2-81.8] vs. 68.3 bpm [IQR 61.5-76.0], p < 0.001). An NN-HR threshold of >67 bpm identified patients at increased risk (risk ratio 2.43, 99 % CI 1.24-5.00) for SAE, however with only moderate predictive performance (F1 score 0.58).

CONCLUSION

Absence of HR below 67 bpm at night, was significantly associated with increased SAE risk, highlighting the potential value of NN-HR as a monitoring target.The potential clinical utility of monitoring NN-HR to prevent SAE warrants further prospective investigation.

Clinical management and therapeutic optimization of patients with heart failure with reduced ejection fraction and low blood pressure. A clinical consensus statement of the Heart Failure Association (HFA) of the ESC

Despite major advancements in heart failure (HF) management and guideline recommendations over the past two decades, real-world evidence highlights suboptimal implementation of guideline-directed medical therapy (GDMT) for HF with reduced ejection fraction (HFrEF). Low blood pressure (BP) is common in HFrEF patients and represents a major perceived barrier to implementing life-saving treatments in clinical practice, as physicians are often concerned about symptomatic hypotension and its consequences. Although low BP can be seen in those hospitalized with signs of shock, the most common scenario involves non-severe, asymptomatic hypotension in patients receiving foundational therapy for HFrEF, where premature down-titration or discontinuation of GDMT should be avoided. This clinical consensus statement provides a comprehensive overview of low BP in HFrEF, including its definition, risk factors, and effects of HF therapies on BP. We propose management pathways to optimize HFrEF treatment in the context of low BP, ultimately aiming to improve patient outcomes.

Hypotensive Episodes on 24-Hour Ambulatory Blood Pressure and Cognitive Function: Insights From the SPRINT Study

BACKGROUND

Hypotensive episodes detected by 24-hour ambulatory blood pressure (BP) monitoring capture daily cumulative hypotensive stress and could be clinically relevant to cognitive impairment, but this relationship remains unclear.

METHODS

We included participants from the Systolic Blood Pressure Intervention Trial (receiving intensive or standard BP treatment) who had 24-hour ambulatory BP monitoring measured near the 27-month visit and subsequent biannual cognitive assessments. We evaluated the associations of hypotensive episodes (defined as systolic BP drops of ≥20 mm Hg between 2 consecutive measurements that reached <100 mm Hg) and hypotensive duration (cumulative time of systolic BP <100 mm Hg) with subsequent cognitive function using adjusted linear mixed models. We further assessed 24-hour average BP and variability.

RESULTS

Among 842 participants with treated hypertension (mean age, 71±9 years; 29% women), the presence (versus absence) of recurrent hypotensive episodes (11%) was associated with lower digit symbol coding scores (difference in Z scores, -0.249 [95% CI, -0.380 to -0.119]) and their faster declines (difference in Z score changes, -0.128 [95% CI, -0.231 to -0.026]). A consistent dose-response association was also observed for longer hypotensive duration with worse Montreal Cognitive Assessment and digit symbol coding scores. The association with digit symbol coding scores remained significant after further adjusting for 24-hour average BP and variability and was not observed for hypotension defined by clinic, orthostatic, or 24-hour average BP. Intensive BP treatment increased 24-hour hypotensive episodes and modified its association with the decline in digit symbol coding score.

CONCLUSION

Twenty-four-hour hypotensive episodes were associated with worse cognitive function, especially in processing speed, and could be a novel marker for optimal BP control and dementia prevention.

Predicting multiple organ dysfunction syndrome in trauma-induced sepsis: Nomogram and machine learning approaches

Background

Multiple organ dysfunction syndrome (MODS) is a critical complication in trauma-induced sepsis patients and is associated with a high mortality rate. This study aimed to develop and validate predictive models for MODS in this patient population using a nomogram and machine learning approaches.

Methods

This retrospective cohort study utilized data from the Medical Information Mart for Intensive Care-IV 2.2 database, focusing on trauma patients diagnosed with sepsis within the first day of intensive care unit (ICU) admission. Predictive variables were extracted from the initial 24 h of ICU data. The dataset (2008-2019) was divided into a training set (2008-2016) and a temporal validation set (2017-2019). Feature selection was conducted using the Boruta algorithm. Predictive models were developed and validated using a nomogram and various machine learning techniques. Model performance was evaluated based on discrimination, calibration, and decision curve analysis.

Results

Among 1295 trauma patients with sepsis, 349 (26.95%) developed MODS. The 28-day mortality rates were 11.21% for non-MODS patients and 23.82% for MODS patients. Key predictors of MODS included the simplified acute physiology score II score, use of mechanical ventilation, and vasopressor administration. In temporal validation, all models significantly outperformed traditional scoring systems (all P <0.05). The nomogram achieved an area under the curve (AUC) of 0.757 (95% confidence interval [CI]: 0.700 to 0.814), while the random forest model demonstrated the highest performance with an AUC of 0.769 (95% CI: 0.712 to 0.826). Calibration plots showed excellent agreement between predicted and observed probabilities, and decision curve analysis indicated a consistently higher net benefit for the newly developed models.

Conclusion

The nomogram and machine learning models provide enhanced predictive accuracy for MODS in trauma-induced sepsis patients compared to traditional scoring systems. These tools, accessible via web-based applications, have the potential to improve early risk stratification and guide clinical decision-making, ultimately enhancing outcomes for trauma patients. Further external validation is recommended to confirm their generalizability.

Impact of norepinephrine versus phenylephrine on brain circulation, organ blood flow and tissue oxygenation in anaesthetised patients with brain tumours: study protocol for a randomised controlled trial

INTRODUCTION

Vasopressor support is often preferred as an efficient and convenient way to raise the blood pressure during surgery and intensive care therapy. However, the optimal vasopressor for ensuring organ blood flow and tissue oxygen delivery during surgery remains undetermined. This study aims to assess the impact of norepinephrine versus phenylephrine on cerebral and non-cerebral organ perfusion and oxygenation during anaesthesia in neurosurgical patients with brain tumours. The study also explores the impact of the vasopressor agents on the distribution of cardiac output between various organs.

METHODS AND ANALYSIS

This is an investigator-initiated, double-blinded, randomised clinical trial including 32 patients scheduled for supratentorial brain tumour surgery. The patients are randomised to receive a phenylephrine or norepinephrine infusion during preoperative positron emission tomography (PET) examinations and the following neurosurgical procedure. PET measurements of blood flow and oxygen metabolism in the brain and other organs are performed on the awake subject during anaesthesia, following a 10% and 20% gradual increase in blood pressure from the baseline value. The primary endpoint is the between-group difference in cerebral blood flow. Secondary endpoints include detection of ischaemic brain lesions possibly associated with vasopressor treatment, changes in cerebral oxygen metabolism, non-cerebral organ blood flow and oxygen metabolism, cardiac output, regional cerebral oxygen saturation, autoregulation and distribution of cardiac output between organs.

ETHICS AND DISSEMINATION

This study was approved by the Danish National Medical Ethics Committee (20 May 2022; 2203674). Results will be disseminated via peer-reviewed publication and presentation at international conferences.

TRIAL REGISTRATION NUMBER

EudraCT no: 2021-006168-26.

CLINICALTRIALS

gov: NCT06083948.

Care guided by tissue oxygenation and haemodynamic monitoring in off-pump coronary artery bypass grafting (Bottomline-CS): assessor blind, single centre, randomised controlled trial

OBJECTIVE

To assess whether perioperative management guided by near-infrared spectroscopy to determine tissue oxygen saturation and haemodynamic monitoring reduces postoperative complications after off-pump coronary artery bypass grafting.

DESIGN

Assessor blinded, single centre, randomised controlled trial (Bottomline-CS trial).

SETTING

A tertiary teaching hospital in China.

PARTICIPANTS

1960 patients aged 60 years or older who were scheduled for elective off-pump coronary artery bypass grafting.

INTERVENTIONS

All patients had multisite monitoring of tissue oxygen saturation (bilateral forehead and unilateral forearm brachioradialis) and haemodynamic monitoring. Both groups received usual care, including arterial blood pressure, central venous pressure, electrocardiography, and transoesophageal echocardiography when indicated. Guided care aimed to maintain tissue oxygenation within 10% above or below preoperative baseline values, established 24-48 hours before surgery, from the start of anaesthesia until extubation or for up to 24 hours postoperatively. In the usual care group, tissue oximetry and haemodynamic data were concealed, and care was routine.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of a composite of 30 day postoperative complications, which were cerebral, cardiac, respiratory, renal, infectious, and mortality complications. Secondary outcomes included the individual components of the composite outcome, new-onset atrial fibrillation, and hospital length of stay.

RESULTS

Of 1960 patients randomly assigned, data from 967 guided care and 974 usual care patients were analysed. During anaesthesia, the area under the curve for tissue oxygen saturation measurements outside the plus and minus 10% baseline range was significantly smaller with guided care than only usual care: left forehead 32.4 versus 57.6 (%×min, P<0.001), right forehead 37.9 versus 62.6 (P<0.001), and forearm 14.8 versus 44.7 (P<0.001). The primary composite outcome occurred in 457/967 (47.3%) patients in the guided care group and 466/974 (47.8%) patients in the usual care group (unadjusted risk ratio 0.99 (95% confidence interval 0.90 to 1.08), P=0.83). No secondary outcomes differed significantly between groups. The largest observed difference was in incidence of pneumonia, which was less frequent in the guided care group (88/967, 9.1%) than in the usual care group (121/974, 12.4%) and not statistically significant after adjusting for multiple comparisons.

CONCLUSIONS

Guided care by use of multisite near-infrared spectroscopy and haemodynamic monitoring effectively maintained tissue oxygenation near baseline levels compared with usual care. However, no clear evidence was noted that this approach reduced the incidence of major postoperative complications. These findings do not support the routine use of near-infrared spectroscopy and haemodynamic monitoring to maintain tissue oxygenation during off-pump coronary artery bypass grafting.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04896736.

Impact of intravenous antihypertensive therapy on cerebral blood flow and neurocognition: a systematic review and meta-analysis

BACKGROUND

Intravenous antihypertensivedrugs are commonly used in acute care settings, yet their impact on cerebral blood flow (CBF) remains uncertain.

METHODS

A systematic review and meta-analysis of 50 studies evaluated the effects of commonly used i.v. antihypertensive agents on CBF in normotensive, hypertensive, and intracranial pathology populations. Meta-analyses used standardised mean differences (SMD), stratified by population type, consciousness state, antihypertensive agent, and CBF measurement method.

RESULTS

Intravenous antihypertensivedrug therapy significantly reduced CBF in normotensive individuals without intracranial pathology (SMD -0.31, 95% confidence interval -0.51 to -0.11), primarily driven by nitroprusside and nitroglycerin in awake subjects (SMD -0.80, 95% confidence interval -1.15 to -0.46), with a median CBF decrease of 14% (interquartile range 13-16%) and a median mean arterial pressure reduction of 17% (interquartile range 9-22%). Other antihypertensives showed no significant effects on CBF in normotensive individuals, nor were changes observed in hypertensive patients or those with intracranial pathology when the median mean arterial pressure reduction was ∼20%. No correlation was found between mean arterial pressure reduction and CBF change, supporting intact cerebral autoregulation. Historical data revealed neurocognitive changes when CBF fell to ∼30 ml 100 g-1 min-1, associated with a 58% mean arterial pressure reduction and a 38% CBF reduction.

CONCLUSIONS

Most i.v. antihypertensive agents do not significantly affect CBF in clinical dose ranges; however, nitroprusside and nitroglycerin can reduce CBF under specific clinical conditions. The certainty of evidence remains low. Neurocognitive changes appear to depend on the magnitude of blood pressure and CBF reductions.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42024511954).

Central Venous Pressure as a Predictor of Acute Kidney Injury in Cardiac Surgery: A Systematic Review of Observational Studies

Background/Objectives: Acute kidney injury (AKI) is a syndrome characterized by impaired kidney function, which is associated with reduced survival and increased morbidity. Central venous pressure (CVP) is a widely used hemodynamic parameter for assessing the volume status of patients and evaluating their response to fluid resuscitation. This systematic review aims to analyze various prospective and retrospective observational and controlled trials to determine the association between CVP and the risk of developing AKI in patients undergoing cardiac surgery. Additionally, it examines whether elevated CVP serves as an accurate predictor of AKI in this patient population. Methods: A systematic review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, using PubMed as the primary database. The search focused on studies published after 2014 that included adult patients undergoing cardiac surgery with reported measurements of CVP and kidney function assessment. Studies conducted on animals, pediatric populations, those published before 2014, or in languages other than English were excluded from the review. Results: Through the analysis of 21 studies, a clear association between higher CVP and increased AKI risk emerged. The most critical CVP thresholds identified were 10 mmHg, 12 mmHg, 14 mmHg, and 20 mmHg, with risk increasing progressively beyond these values. CVP ≥ 10 mmHg was the most commonly reported cutoff for elevated AKI risk, showing 1.42 to 4.53 times increased odds. CVP ≥ 12 mmHg further amplified the risk, while CVP ≥ 14 mmHg was consistently associated with severe AKI and the need for RRT. The highest threshold (CVP ≥ 20 mmHg) showed the greatest risk escalation, linked to fluid overload, right heart failure, and mortality. Studies also suggest an optimal CVP range of 6-8 mmHg to minimize AKI incidence. Conclusions: Elevated CVP is an independent risk factor for the development of AKI in patients undergoing cardiac surgery. These findings suggest that CVP monitoring can play a significant role in predicting AKI and guiding perioperative management strategies.

Butyrate increases cardiac output and causes vasorelaxation in a healthy porcine model

BACKGROUND

Butyrate, a short-chain fatty acid, has shown potential to improve left ventricular (LV) function and induce vasorelaxation in rodents. Butyrate may either be produced by the microbiome in the colon, be ingested or administered intravenously. This study aimed to evaluate effects of butyrate on cardiac output (CO) and associated hemodynamic variables in a porcine model.

METHODS

In a randomized, blinded crossover study, ten healthy 60-kg pigs were given three hour infusions of 600 mM butyrate and equimolar sodium chloride (control). CO was measured by thermodilution via a pulmonary artery catheter. LV contractility was assessed using pressure-volume admittance catheterization. Additionally, isolated porcine coronary arteries were exposed to butyrate in a wire myograph to evaluate vasorelaxation.

RESULTS

Butyrate infusion increased plasma butyrate concentration to 0.53 mM (95 % confidence interval (CI): 0.49 to 0.58 mM, P < 0.58 mM, P < 0.001) and CO by 1.6 L/min (95 % CI: 1.0 to 2.1 L/min, P < 0.001) compared with the control. Heart rate, LV ejection fraction, cardiac efficiency and dP/dtmax rose, while systemic vascular resistance, arterial elastance, mean arterial pressure and LV end-systolic volume decreased. Load-independent LV contractility and stroke volume did not significantly differ. In the myograph, porcine coronary arteries relaxed in response to butyrate in a concentration-dependent manner.

CONCLUSION

Butyrate increases cardiac output and lowers vascular resistance in a large animal model, through increased HR and systemic vasorelaxation. Load-independent LV contractility was not significantly altered. We observed indices of increased end-organ perfusion. These potentially beneficial cardiovascular properties of butyrate should be further studied.

Airway pressure as a predictor of cardiac output reduction in prone position spine surgery: A prospective observational study

BACKGROUND

The prone position is commonly used in surgical procedures and is known to cause significant hemodynamic changes, particularly a reduction in cardiac output. This study aimed to explore the relationship between intra-abdominal pressure (IAP), airway pressure, and cardiac output during spine surgeries under general anesthesia.

METHODS

Twenty-five patients undergoing elective spine surgery in the prone position were enrolled in this prospective observational study. Cardiac output was monitored using pulse contour analysis, while IAP was measured by the bladder method and airway pressure was recorded from anesthesia machine. Changes in these parameters were analyzed to predict a ≥25% reduction in cardiac output after transitioning from the supine to prone position.

RESULTS

Transitioning to the prone position significantly increased both IAP and airway pressure (p < 0.001), while cardiac output decreased by 13%. No significant correlation was observed between changes in IAP and cardiac output; however, a negative correlation was found between increased airway pressure and reduced cardiac output (r = -0.40, p = 0.049). The area under the receiver operating characteristic curve for airway pressure change predicting significant cardiac output reduction was 0.88 (p < 0.001).

CONCLUSION

Airway pressure is a reliable and noninvasive predictor of significant cardiac output reduction in patients undergoing prone position surgery. Monitoring airway pressure may help identify patients at risk for hemodynamic instability during surgery.

Monitoring of perioperative tissue perfusion and impact on patient outcomes

Monitoring perioperative tissue perfusion is crucial in clinical anesthesia to protect organs and ensure patient safety. Indicators like hemodynamic parameters, tissue metabolism, and microcirculation markers are used for assessment. Studies show intraoperative hypotension negatively impacts outcomes, though blood pressure alone may not reflect tissue perfusion accurately. Cardiac output is a more direct measure, with adequate levels generally indicating good perfusion. However, some conditions cause adequate cardiac output but inadequate perfusion. Non-quantitative markers like skin color and temperature, and quantitative indicators like tissue oxygen saturation and laser Doppler flowmetry, help assess microcirculation but can't fully evaluate systemic perfusion. Near-Infrared Spectroscopy (NIRS) monitors tissue oxygen metabolism, reflecting oxygen supply and consumption balance. Central venous oxygen saturation offers a better systemic overview but may not always indicate good perfusion, especially in sepsis. Lactic acid levels closely correlate with tissue perfusion and outcomes, with dynamic changes being more indicative than single measurements. Effective monitoring requires evaluating both macro- and microcirculation states and systemic metabolic levels to ensure optimal outcomes. Combining these measures provides a more accurate assessment of tissue perfusion and patient prognosis.

Identification of potentially causative drugs associated with hypotension: A scoping review

Drug-induced hypotension can be harmful and may lead to hospital admissions. The occurrence of hypotension during drug therapy is preventable through increased awareness. This scoping review aimed to provide a comprehensive overview of antihypertensive and nonantihypertensive drugs associated with hypotension in adults. A systematic literature search was conducted using MEDLINE, Embase and Cochrane Library, focusing on studies from January 2013 to May 2023. Search terms were developed to capture key concepts related to hypotension and adverse drug events in adults while excluding terms related to allergic reactions, phytotherapy and studies involving paediatric, pregnant or animal populations. The eligibility criteria included a wide range of study types evaluating hypotension as an adverse drug event across all healthcare settings. Relevant information was extracted from the included studies, while identified drugs associated with hypotension were categorised into drug classes. The review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews checklist. In 97 eligible studies, we identified 26 antihypertensive drugs grouped into nine different antihypertensive classes and 158 other drugs grouped into 22 other drug classes. Common antihypertensive classes were angiotensin-converting enzyme inhibitors, beta blockers and diuretics. Frequently reported nonantihypertensive classes were neuroleptics, alpha-1 blockers for benign prostatic hyperplasia, benzodiazepines, opioids and antidepressants. The results highlight the importance of healthcare professionals being aware of nonantihypertensive drugs that can cause hypotension. This review provides a basis for future systematic reviews to explore dose-dependence, drug-drug interactions and confounding factors.

Machine Learning-Based Cardiac Output Estimation Using Photoplethysmography in Off-Pump Coronary Artery Bypass Surgery

Background/Objectives: Hemodynamic monitoring is crucial for managing critically ill patients and those undergoing major surgeries. Cardiac output (CO) is an essential marker for diagnosing hemodynamic deterioration and guiding interventions. The gold standard thermodilution method for measuring CO is invasive, prompting a search for non-invasive alternatives. This pilot study aimed to develop a non-invasive algorithm for classifying the cardiac index (CI) into low and non-low categories using finger photoplethysmography (PPG) and a machine learning model. Methods: PPG and continuous thermodilution CO data were collected from patients undergoing off-pump coronary artery bypass graft surgery. The dataset underwent preprocessing, and features were extracted and selected using the Relief algorithm. A CatBoost machine learning model was trained and evaluated using a validation and testing phase approach. Results: The developed model achieved an accuracy of 89.42% in the validation phase and 87.57% in the testing phase. Performance was balanced across low and non-low CO categories, demonstrating robust classification capabilities. Conclusions: This study demonstrates the potential of machine learning and non-invasive PPG for accurate CO classification. The proposed method could enhance patient safety and comfort in critical care and surgical settings by providing a non-invasive alternative to traditional invasive CO monitoring techniques. Further research is needed to validate these findings in larger, diverse patient populations and clinical scenarios.

Adequacy of Anesthesia Guidance for Combined General/Epidural Anesthesia in Patients Undergoing Open Abdominal Infrarenal Aortic Aneurysm Repair; Preliminary Report on Hemodynamic Stability and Pain Perception

Background/Objectives: Hemodynamic instability and inappropriate postoperative pain perception (IPPP) with their consequences constitute an anesthesiological challenge in patients undergoing primary elective open lumbar infrarenal aortic aneurysm repair (OLIAAR) under general anesthesia (GA), as suboptimal administration of intravenous rescue opioid analgesics (IROAs), whose titration is optimized by Adequacy of Anaesthesia (AoA) guidance, constitutes a risk of adverse events. Intravenous or thoracic epidural anesthesia (TEA) techniques of preventive analgesia have been added to GA to minimize these adverse events. Methods: Seventy-five patients undergoing OLIAAR were randomly assigned to receive TEA with 0.2% ropivacaine (RPV) with fentanyl (FNT) 2.5 μg/mL (RPV group) or 0.2% bupivacaine (BPV) with FNT 2.5 μg/mL (BPV group) or intravenous metamizole/tramadol (MT group). IROA using FNT during GA was administered under AoA guidance. Systemic morphine was administered as a rescue agent in all groups postoperatively in the case of IPPP, assessed using the Numeric Pain Rating Score > 3. The maximum score at admission and the minimum at discharge from the postoperative care unit to the Department of Vascular Surgery, perioperative hemodynamic stability, and demand for rescue opioid analgesia were analyzed. Results: Ultimately, 57 patients were analyzed. In 49% of patients undergoing OLIAAR, preventive analgesia did not prevent the incidence of IPPP, which was not statistically significant between groups. No case of acute postoperative pain perception was noted in the RPV group, but at the cost of statistically significant minimum mean arterial pressure values, reflecting hemodynamic instability, with clinical significance < 65mmHg. Demand for postoperative morphine was not statistically significantly different between groups, contrary to significantly lower doses of IROA using FNT in patients receiving TEA. Conclusions: AoA guidance for IROA administration with FNT blunted the preventive analgesia effect of TEA compared with intravenous MT that ensured proper perioperative hemodynamic stability along with adequate postoperative pain control with acceptable demand for postoperative morphine.

Lassen's Cerebral Autoregulation Plot Revisited and Validated 65 Years Later: Impacts of Vasoactive Drug Treatment on Cerebral Blood Flow

Niels Lassen's seminal 1959 cerebral autoregulation plot, a cornerstone in understanding the relationship between mean arterial pressure (MAP) and cerebral blood flow (CBF), was based on preexisting literature. However, this work has faced criticism for selective data presentation, leading to inaccurate interpretation. This review revisits and validates Lassen's original plot using contemporary data published since 2000. Additionally, we aim to understand the impact of vasoactive drug treatments on CBF, as Lassen's referenced studies used various drugs for blood pressure manipulation. Our findings confirm Lassen's concept of a plateau where CBF remains relatively stable across a specific MAP range in awake humans with normal brains. However, significant variations in cerebral autoregulation among different populations are evident. In critically ill patients and those with traumatic brain injury, the autoregulatory plateau dissipates, necessitating tight blood pressure control to avoid inadequate or excessive cerebral perfusion. A plateau is observed in patients anesthetized with intravenous agents but not with volatile agents. Vasopressor treatments have population-dependent effects, with contemporary data showing increased CBF in critically ill patients but not in awake humans with normal brains. Vasopressor treatment results in a greater increase in CBF during volatile than intravenous anesthesia. Modern antihypertensives do not significantly impact CBF based on contemporary data, exerting a smaller impact on CBF compared to historical data. These insights underscore the importance of individualized blood pressure management guided by modern data in the context of cerebral autoregulation across varied patient populations.

Efficacy and safety of intraoperative controlled hypotension: a systematic review and meta-analysis of randomised trials

BACKGROUND

Intraoperative controlled hypotension improves surgical field visibility by reducing blood loss (efficacy) but poses potential risks linked to organ hypoperfusion (safety). The use of controlled hypotension persists despite increasing evidence of associations between intraoperative inadvertent hypotension and adverse outcomes. Therefore, we tested the hypothesis that the focus and results of intraoperative controlled hypertension research differ across anaesthesia and surgery investigators because of differing priorities.

METHODS

We systematically reviewed randomised trials comparing controlled hypotension with usual care with trials categorised by investigators' affiliation.

RESULTS

We identified 48 eligible trials, of which 37 were conducted by anaesthesia investigators and 11 by surgery investigators. For the primary outcome, 54% of the anaesthesia-led trials focused on safety, whereas all (100%) surgery-led trials focused on efficacy (P=0.004). Compared with usual care, mean arterial pressure in controlled hypotension was 23% (95% confidence interval [CI] 17-29%) lower in anaesthesia trials and 30% (95% CI 14-37%) lower in surgery trials; estimated blood loss was 44% (95% CI 30-55%) less in anaesthesia trials and 38% (95% CI 30-49%) less in surgery trials. Overall, blood loss was reduced by 43% (95% CI 32-53%), and trial sequential analysis supported an efficacy conclusion. Mean arterial pressure and estimated blood loss reductions were associated (R2=0.41, P=0.002). All trials were underpowered for safety outcomes, and none adequately evaluated myocardial or renal injury.

CONCLUSIONS

Anaesthesia researchers prioritised safety outcomes, whereas surgery researchers emphasised efficacy in controlled hypotension trials. Controlled hypotension significantly reduces blood loss. In contrast, safety outcomes were poorly studied. Given increasing observational evidence linking inadvertent hypotension to myocardial and renal injury, the safety of controlled hypotension remains to be addressed.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023450397).

Correlation between blood pressure and mortality in older critically ill patients: Insights from a large intensive care unit database

OBJECTIVES

The study aimed to investigate the relationship between blood pressure (BP) levels and mortality among critically ill older adults in the intensive care unit (ICU), establish optimal BP target for this population, and assess the mediating effect of severe malnutrition on BP-related mortality.

METHODS

Data were extracted from the Medical Information Mart for Intensive Care IV version 2.2 database, focusing on critically ill patients aged 80 years and older. The analysis included various BP parameters, such as systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP).

RESULTS

The study cohort comprised 14,660 critically ill patients, of whom 1558 (10.6 %) experienced ICU mortality and 2493 (17.0 %) experienced in-hospital mortality. Lower BP levels (SBP ≤ 112 mmHg; DBP ≤ 53 mmHg; MAP ≤65 mmHg), were associated with an increased risk of both ICU and in-hospital mortality. Notably, only reduced SBP levels were linked to a higher risk of 1-year mortality, with an adjusted hazard ratio 1.13 (95 % confidence interval 1.05 to 1.23). Additionally, severe malnutrition was identified as a mediator in the relationship between low BP levels and ICU mortality, with BP levels positively correlated with prognostic nutritional indexes.

CONCLUSION

Among critically ill older adults, lower BP levels are significantly associated with higher risks of ICU and in-hospital mortality, while reduced SBP levels are linked to 1-year mortality. These findings emphasize the importance of assessing nutritional status in older ICU patients with low BP levels to potentially mitigate mortality risk.

Risk Factors and Outcomes of Patients with Pseudomonas aeruginosa Bloodstream Infection in the Intensive Care Unit

Background: Bloodstream infections (BSIs) caused by Pseudomonas aeruginosa have high mortality rates and pose a significant threat to healthcare settings. Objectives: We aimed to investigate the clinical risk factors related to mortality and the development of P. aeruginosa with difficult-to-treat resistance (DTR-PA) BSI in the intensive care unit. Methods: This was a retrospective, single-center study that included patients with P. aeruginosa BSI who were hospitalized between 2020 and 2022. The risk factors affecting 30-day mortality and the development of DTR-PA were investigated using both univariate and multivariate analyses. Results: A total of 140 patients were analyzed. The mean age was (66 ± 17.5) years, and 48% of the patients were male. Previous meropenem use was an independent risk factor for DTR-PA BSI (odds ratio, 2.68; 95% CI, 1.24 to 5.80; P = 0.012). Multivariate analysis demonstrated that the requirement for inotropic support was an independent risk factor for 30-day mortality [hazard ratio, 2.50; 95% confidence interval (CI), 1.33 to 4.68; P = 0.004]. Conclusions: Prior meropenem use was an independent risk factor for DTR-PA development. Strict policies for Carbapenem use and infection control procedures are essential to combat infections caused by DTR-PA.

Cardiac Failure and Cardiogenic Shock: Insights Into Pathophysiology, Classification, and Hemodynamic Assessment

Heart failure is defined as increased intracardiac pressures, either alone or combined with reduced cardiac output. Clinically, it is presented with signs and symptoms of congestion and compensated perfusion. Cardiogenic shock, on the other hand, is the spectrum of hemodynamic disturbances that lead to hypoperfusion or need for circulatory support, due to cardiac disease. Both entities affect millions of people worldwide, have a dismal prognosis, and constitute a severe socioeconomic burden. Heart failure can be the aftermath of ischemic heart disease, hypertension, arrhythmias, or cardiomyopathies. It undergoes multiple classifications, facilitating its investigation and treatment. The pathogenetic mechanisms differ in various types of heart failure, regarding the affected ventricles, the duration of symptoms, and their primary/secondary onset. These mechanisms reflect the complex interactions between cardiopulmonary, vascular, and hepatorenal systems. Acute deterioration of cardiac function can lead to cardiogenic shock. Myocardial infarction accounts for 81% of such cases. Healthy lifestyle and timely management of coronary artery disease are paramount, as they can prevent this life-threatening situation and reduce mortality and the economic burden for healthcare systems. Irrespective of the etiology, cardiogenic shock is interpreted using the pressure-volume loop. This can be modified for each ventricle, the underlying pathophysiology, and the time since symptoms' onset. It therefore provides valuable information about the native circulation and the expected alterations under mechanical or pharmacological support, facilitating the decision-making progress. In 2019, given the phenotypical heterogeneity of cardiogenic shock, the Society for Cardiovascular Angiography and Interventions introduced a classification system. According to this, patients are stratified in five stages proportionally to the severity of their condition. Aside from this classification, various biochemical, imaging, and hemodynamic monitoring indices are used to assess coagulation pathway and cardiac, hepatorenal, and pulmonary function, enabling the heart team to tailor therapy. Additionally, the prognostication progress is facilitated by scores, such as the Observatoire Regional Breton sur l'Infarctus (ORBI) score, the intra-aortic balloon pump (IABP) SHOCK-II score, and the CardShock score, indicating suitable escalation or de-escalation strategies. Despite the current progress, there are several areas of advancement regarding the role of vasoactive drugs in cardiogenic shock, revascularization options, mechanical ventilation patterns, hypothermia treatment, and mechanical circulatory support protocols.

Noradrenaline-induced changes in cerebral blood flow in health, traumatic brain injury and critical illness: a systematic review with meta-analysis

BACKGROUND

Noradrenaline is a standard treatment for hypotension in acute care. The precise effects of noradrenaline on cerebral blood flow in health and disease remain unclear.

METHODS

We systematically reviewed and synthesised data from studies examining changes in cerebral blood flow in healthy participants and patients with traumatic brain injury and critical illness.

RESULTS

Twenty-eight eligible studies were included. In healthy subjects and patients without critical illness or traumatic brain injury, noradrenaline did not significantly change cerebral blood flow velocity (-1.7%, 95%CI -4.7-1.3%) despite a 24.1% (95%CI 19.4-28.7%) increase in mean arterial pressure. In patients with traumatic brain injury, noradrenaline significantly increased cerebral blood flow velocity (21.5%, 95%CI 11.0-32.0%), along with a 33.8% (95%CI 14.7-52.9%) increase in mean arterial pressure. In patients who were critically ill, noradrenaline significantly increased cerebral blood flow velocity (20.0%, 95%CI 9.7-30.3%), along with a 32.4% (95%CI 25.0-39.9%) increase in mean arterial pressure. Our analyses suggest intact cerebral autoregulation in healthy subjects and patients without critical illness or traumatic brain injury., and impaired cerebral autoregulation in patients with traumatic brain injury and who were critically ill. The extent of mean arterial pressure changes and the pre-treatment blood pressure levels may affect the magnitude of cerebral blood flow changes. Studies assessing cerebral blood flow using non-transcranial Doppler methods were inadequate and heterogeneous in enabling meaningful meta-analysis.

CONCLUSIONS

Noradrenaline significantly increases cerebral blood flow in humans with impaired, not intact, cerebral autoregulation, with the extent of changes related to the severity of functional impairment, the extent of mean arterial pressure changes and pre-treatment blood pressure levels.

PeriOperative Quality Initiative (POQI) international consensus statement on perioperative arterial pressure management

Arterial pressure monitoring and management are mainstays of haemodynamic therapy in patients having surgery. This article presents updated consensus statements and recommendations on perioperative arterial pressure management developed during the 11th POQI PeriOperative Quality Initiative (POQI) consensus conference held in London, UK, on June 4-6, 2023, which included a diverse group of international experts. Based on a modified Delphi approach, we recommend keeping intraoperative mean arterial pressure ≥60 mm Hg in at-risk patients. We further recommend increasing mean arterial pressure targets when venous or compartment pressures are elevated and treating hypotension based on presumed underlying causes. When intraoperative hypertension is treated, we recommend doing so carefully to avoid hypotension. Clinicians should consider continuous intraoperative arterial pressure monitoring as it can help reduce the severity and duration of hypotension compared to intermittent arterial pressure monitoring. Postoperative hypotension is often unrecognised and might be more important than intraoperative hypotension because it is often prolonged and untreated. Future research should focus on identifying patient-specific and organ-specific hypotension harm thresholds and optimal treatment strategies for intraoperative hypotension including choice of vasopressors. Research is also needed to guide monitoring and management strategies for recognising, preventing, and treating postoperative hypotension.

Assessing the Risks and Benefits of Hypotensive Anesthesia and Piezosurgical Instruments in Bimaxillary Surgery

The challenge in bimaxillary surgery lies in significant intraoperative bleeding, prompting various strategies to minimize blood loss. Among the methods considered for controlling intraoperative bleeding, hypotensive anesthesia and the use of piezosurgical instruments (Osada, Tokyo, Japan) have been explored. However, hypotensive anesthesia may have adverse effects on cardiac function, and surgical time is likely to be prolonged when using piezosurgical instruments. This study retrospectively examined whether the combined use of hypotensive anesthesia and piezosurgical instruments reduces intraoperative bleeding and whether the combination impacts cardiac function. The combination of hypotensive anesthesia and piezosurgical instruments significantly reduced intraoperative bleeding. Furthermore, the combination was associated with a significantly higher incidence of tachycardia, particularly with the use of nicardipine. Additionally, the combination significantly lengthened the duration of the surgery and may have increased the burden on cardiac function. Landiolol was effectively employed to manage tachycardia. When selecting hypotensive anesthesia as a means to limit bleeding, proactive preparation and preventive small-dose administration of landiolol could be beneficial in managing the potential occurrence of tachycardia.

The MINUTES bundle for the initial 30 min management of undifferentiated circulatory shock: an expert opinion

Acute circulatory shock is a life-threatening emergency requiring an efficient and timely management plan, which varies according to shock etiology and pathophysiology. Specific guidelines have been developed for each type of shock; however, there is a need for a clear timeline to promptly implement initial life-saving interventions during the early phase of shock recognition and management. A simple, easily memorable bundle of interventions could facilitate standardized management with clear targets and specified timeline. The authors propose the "MINUTES" acronym which summarizes essential interventions which should be performed within the first 30 min following shock recognition. All the interventions in the MINUTES bundle are suitable for any patient with undifferentiated shock. In addition to the acronym, we suggest a timeline for each step, balancing the feasibility and urgency of each intervention. The MINUTES acronym includes seven sequential steps which should be performed in the first 30 min following shock recognition: Maintain "ABCs", INfuse vasopressors and/or fluids (to support hemodynamic/perfusion) and INvestigate with simple blood tests, Ultrasound to detect the type of shock, Treat the underlying Etiology, and Stabilize organ perfusion.

Acute cardiac autonomic and hemodynamic responses to resistive breathing: Effect of loading type and intensity

OBJECTIVES

This study aimed to assess the acute impact of distinct loading breathing types and intensities on cardiac autonomic function and hemodynamic responses in healthy young adults.

METHODS

A randomized, crossover trial involved 28 participants who underwent inspiratory resistive breathing, expiratory resistive breathing (ERB) and combined resistive breathing, each at 30% and 60% of maximal respiratory pressures. Data on heart rate variability (HRV) and hemodynamic parameters were collected during each trial.

RESULTS

The study revealed significant main and interaction effects for both the performed task and the intensity across all measured variables (all p < 0.001). ERB at 60% load demonstrated significantly higher HRV values in the standard deviation of normal-to-normal RR intervals, the square root of the mean squared difference of successive normal-to-normal RR intervals and high-frequency power, as well as significantly lower values in heart rate, stroke volume, stroke volume index, cardiac output, cardiac index, end-diastolic volume and end-diastolic volume index, compared to other loaded protocols (all p < 0.001).

CONCLUSION

These findings highlight the acute effect of type-specific and load-dependent resistive breathing on cardiac autonomic and hemodynamic functions, where ERB at 60% intensity showed the most significant cardiovagal modulation while causing the least hemodynamic alterations.

The exploration of perioperative hypotension subtypes: a prospective, single cohort, observational pilot study

Background

Hypotension is a risk factor for postoperative complications, but evidence from randomized trials does not support that a higher blood pressure target always leads to optimized outcomes. The heterogeneity of underlying hemodynamics during hypotension may contribute to these contradictory results. Exploring the subtypes of hypotension can enable optimal management of intraoperative hypotension.

Methods

This is a prospective, observational pilot study. Patients who were ≥ 45 years old and scheduled to undergo moderate-to-high-risk noncardiac surgery were enrolled in this study. The primary objective of this pilot study was to investigate the frequency and distribution of perioperative hypotension and its subtypes (hypotension with or without cardiac output reduction). The exposure of hypotension and its subtypes in patients with and without myocardial or acute kidney injury were also explored.

Results

Sixty patients were included in the analysis. 83% (50/60) of the patients experienced perioperative hypotension. The median duration of hypotension for each patient was 8.0 [interquartile range, 3.1-23.3] minutes. Reduced cardiac output was present during 77% of the hypotension duration. Patients suffering from postoperative myocardial or acute kidney injury displayed longer duration and more extensive exposure in all hypotension subtypes. However, the percentage of different hypotension subtypes did not differ in patients with or without postoperative myocardial or acute kidney injury.

Conclusion

Perioperative hypotension was frequently accompanied by cardiac output reduction in moderate-to-high-risk noncardiac surgical patients. However, due to the pilot nature of this study, the relationship between hypotension subtypes and postoperative myocardial or acute kidney injury still needs further exploration.

Clinical trial registration

https://www.chictr.org.cn/showprojEN.html?proj=134260, CTR2200055929.

Hemodynamic Bedside Monitoring Instrument with Pressure and Optical Sensors: Validation and Modality Comparison

Results from two independent clinical validation studies for measuring hemodynamics at the patient's bedside using a compact finger probe are reported. Technology comprises a barometric pressure sensor, and in one implementation, additionally, an optical sensor for photoplethysmography (PPG) is developed, which can be used to measure blood pressure and analyze rhythm, including the continuous detection of atrial fibrillation. The capabilities of the technology are shown in several form factors, including a miniaturized version resembling a common pulse oximeter to which the technology could be integrated in. Several main results are presented: i) the miniature finger probe meets the accuracy requirements of non-invasive blood pressure instrument validation standard, ii) atrial fibrillation can be detected during the blood pressure measurement and in a continuous recording, iii) a unique comparison between optical and pressure sensing mechanisms is provided, which shows that the origin of both modalities can be explained using a pressure-volume model and that recordings are close to identical between the sensors. The benefits and limitations of both modalities in hemodynamic monitoring are further discussed.

24-h central pressure is a valuable predictor for left ventricular hypertrophy in non-dialysis patients with chronic kidney disease

The current research on the relationship between 24-h central pressure and 24-h brachial pressure with left ventricular hypertrophy (LVH) is characterised by limited sample size and inconsistent findings. Furthermore, the association has never been explored in chronic kidney disease (CKD). A multicentre, cross-sectional study among non-dialysis patients with CKD was conducted. All participants underwent brachial and central ambulatory blood pressure monitoring using MobilO-Graph PWA, while trained cardiologists performed echocardiography. In this study, 2117 non-dialysis patients with CKD were examined. 24-h central systolic blood pressure with c2 calibration (24-h c2SBP) demonstrated a stronger association with left ventricular mass index and LVH compared with 24-h brachial systolic blood pressure (24-h bSBP) in the univariate and multivariate regression analyses. The multivariate net reclassification index (NRI) analysis revealed that 24-h c2SBP exhibited greater discriminatory power over 24-h bSBP (NRI = 0.310, 95% CI [0.192-0.429], P < 0.001). Applying 130/135 mmHg as the threshold for 24-h bSBP/c2SBP to cross-classify, the patients were divided into concordant normotension (1509 individuals), isolated brachial hypertension (155 individuals), isolated central hypertension (11 individuals), and concordant hypertension (442 individuals). With concordant normotension as the reference, the multivariable-adjusted ORs were 0.954 (95% CI, 0.534-1.640; P = 0.870) for isolated brachial hypertension and 2.585 (95%CI, 1.841-3.633; P < 0.001) for concordant hypertension. Among non-dialysis patients with CKD, 24-h c2SBP exhibits greater efficacy in identifying the presence of LVH compared with 24-h bSBP. The presence of LVH was greater in cases of concordant hypertension compared with cases of isolated brachial hypertension and concordant normotension.

Construction of a mortality risk prediction model for patients with acute diquat poisoning based on clinically accessible data

BACKGROUND

To examine the risk factors associated with mortality in individuals suffering from acute diquat poisoning and to develop an effective prediction model using clinical data.

METHODS

A retrospective review was conducted on the clinical records of 107 individuals who were hospitalized for acute diquat poisoning at a tertiary hospital in Sichuan Province between January 2017 and September 30, 2023, and further categorized into survivor and nonsurvivor groups based on their mortality status within 30 days of poisoning. The patient's demographic information, symptoms within 24 h of admission, and details of the initial clinical ancillary examination, as well as the APACHE II score, were documented. The model was developed using backward stepwise logistic regression, and its performance was assessed using receiver operating characteristic curves, calibration curves, Brier scores, decision curve analysis curves, and bootstrap replicates for internal validation.

RESULTS

Multifactorial logistic regression analysis revealed that blood pressure (hypertension, OR 19.73, 95% CI 5.71-68.16; hypotension, OR 61.38, 95% CI 7.40-509.51), white blood count (OR 1.35, 95% CI 1.20-1.52), red cell distribution width-standard deviation (OR 1.22, 95% CI 1.08-1.38), and glomerular filtration rate (OR 0.96, 95% CI 0.94-0.97) were identified as independent risk factors for mortality in patients with diquat. Subsequently, a nomogram with an area under the curve of 0.97 (95% CI: 0.93-1) was developed. Internal bootstrap resampling (1000 repetitions) confirmed the model's adequate discriminatory power, with an area under the curve of 0.97. Decision curve analysis demonstrated greater net gains for the nomogram, while the clinical impact curves indicated greater predictive validity.

CONCLUSION

The nomogram model developed in this study using available clinical data enhances the prediction of risk for DQ patients and has the potential to provide valuable clinical insights to guide patient treatment decisions.

The effect of proactive versus reactive treatment of hypotension on postoperative disability and outcome in surgical patients under anaesthesia (PRETREAT): clinical trial protocol and considerations

Background

Intraoperative hypotension has been extensively studied for its association with adverse outcomes. However, small sample sizes and methodological issues limit the causal inference that can be drawn.

Methods

In this multicentre, adaptive, randomised controlled trial, we will include 5000 adult inpatients scheduled for elective non-cardiac surgery under general or central neuraxial anaesthesia. Patients will be either randomly allocated to the intervention or care-as-usual group using computer-generated blocks of four, six, or eight, with an allocation ratio of 1:1. In the intervention arm patients will be divided into low-, intermediate-, and high-risk groups based on their likelihood to experience intraoperative hypotension, with resulting mean blood pressure targets of 70, 80, and 90 mm Hg, respectively. Anaesthesia teams will be provided with a clinical guideline on how to keep patients at their target blood pressure. During the first 6 months of the trial the intervention strategy will be evaluated and further revised in adaptation cycles of 3 weeks if necessary, to improve successful impact on the clinical process. The primary outcome is postoperative disability after 6 months measured with the World Health Organization Disability Assessment Score (WHODAS) 2.0 questionnaire.

Ethics and dissemination

This study protocol has been approved by the Medical Ethics Committee of the University Medical Centre Utrecht (20-749) and all protocol amendments will be communicated to the Medical Ethics Committee. The study protocol is in adherence with the Declaration of Helsinki and the guideline of Good Clinical Practice. Dissemination plans include publication in a peer-reviewed journal.

Clinical trial registration

The Dutch Trial Register, NL9391. Registered on 22 March 2021.

Hypotension prediction index for the prevention of hypotension during surgery and critical care: A narrative review

Surgeons and anesthesia clinicians commonly face a hemodynamic disturbance known as intraoperative hypotension (IOH), which has been linked to more severe postoperative outcomes and increases mortality rates. Increased occurrence of IOH has been positively associated with mortality and incidence of myocardial infarction, stroke, and organ dysfunction hypertension. Hence, early detection and recognition of IOH is meaningful for perioperative management. Currently, when hypotension occurs, clinicians use vasopressor or fluid therapy to intervene as IOH develops but interventions should be taken before hypotension occurs; therefore, the Hypotension Prediction Index (HPI) method can be used to help clinicians further react to the IOH process. This literature review evaluates the HPI method, which can reliably predict hypotension several minutes before a hypotensive event and is beneficial for patients' outcomes.

Continuous cardiac output estimation using a new modified Fick method during off-pump coronary artery bypass graft surgery: a retrospective observational study

PURPOSE

Several technical aspects of the Fick method limit its use intraoperatively. A data-driven modification of the Fick method may enable its use in intraoperative settings.

METHODS

This two-center retrospective observational study included 57 (28 and 29 in each center) patients who underwent off-pump coronary artery bypass graft (OPCAB) surgery. Intraoperative recordings of physiological data were obtained and divided into training and test datasets. The Fick equation was used to calculate cardiac output (CO-Fick) using ventilator-determined variables, intraoperative hemoglobin level, and SvO2, with continuous thermodilution cardiac output (CCO) used as a reference. A modification CO-Fick was derived and validated: CO-Fick-AD, which adjusts the denominator of the original equation.

RESULTS

Increased deviation between CO-Fick and CCO was observed when oxygen extraction was low. The root mean square error of CO-Fick was decreased from 6.07 L/min to 0.70 L/min after the modification. CO-Fick-AD showed a mean bias of 0.17 (95% CI 0.00-0.34) L/min, with a 36.4% (95% CI 30.6-44.4%) error. The concordance rates of CO-Fick-AD ranged from 73.3 to 87.1% depending on the time interval and exclusion zone.

CONCLUSIONS

The original Fick method is not reliable when oxygen extraction is low, but a modification using data-driven approach could enable continuous estimation of cardiac output during the dynamic intraoperative period with minimal bias. However, further improvements in precision and trending ability are needed.

Hypotensive Levels on Endoscopic Sinus Surgery Visibility: A Randomized Non-Inferiority Trial

OBJECTIVE

Optimization of endoscopic sinus surgery (ESS) conditions is a common focus of interest for otolaryngologists and anesthesiologists. Relying on hypotension alone to achieve a bloodless field may not without risks. We sought to determine whether ESS is feasible in the context of moderate hypotension.

METHODS

This randomized non-inferiority trial enrolled 96 adult patients who were to undergo ESS. The patients were divided into two groups: Controlled hypotension group (n = 48, MAP reduction to 55-65 mmHg, minimum of 60% of baseline blood pressure) or Individualized hypotension group (n = 48, MAP reduction to 75-80% of baseline blood pressure). All participants were placed in 10° reverse Trendelenburg position during ESS, and cottonoid patties dammed with epinephrine was recommended to clear the operative field of bleeding. The two groups were compared according to Boezaart grading scale (BS) score, estimated blood loss, blood loss rate, arterial lactate level and postoperative recovery.

RESULTS

Both levels of intraoperative hypotension (62.2 ± 2.3 mmHg vs. 74.0 ± 2.8 mmHg) provided acceptable surgical conditions with no difference in mean BS scores [2.00 (1.88-2.33) vs. 2.00 (1.85-2.45), p = 0.926]. The 95% CI for median value differences in mean BS scores is lower than the preset non-inferiority margin. There were no differences in blood loss rate and estimated blood loss between two groups (p > 0.05) Postoperative arterial lactate and Ramsay sedation scores were significantly different between the two groups (p < 0.05).

CONCLUSIONS

In ESS, both levels of intraoperative hypotension, combined with position adjustment and low-concentration adrenaline to constrict nasal mucosal blood vessels, provided acceptable surgical conditions.

LEVEL OF EVIDENCE

2 Laryngoscope, 134:569-576, 2024.

Intraoperative blood pressure and cardiac complications after aneurysmal subarachnoid hemorrhage: a retrospective cohort study

BACKGROUND

Previous studies report that intraoperative hypotension worsens outcomes after aneurysmal subarachnoid hemorrhage (aSAH). However, the hypotensive harm threshold for major adverse cardiovascular events (MACE) remains unclear.

METHODS

The authors included aSAH patients who had general anesthesia for aneurysmal clipping/coiling. MACE were defined by a composite of acute myocardial injury, acute myocardial infarction, and other cardiovascular complications identified by electrocardiogram and echocardiography. The authors initially used logistic regression and change-point analysis based on the second derivative to identify mean arterial pressure (MAP) of 75 mmHg as the harm threshold. Thereafter, our major exposure was MAP below 75 mmHg characterized by area, duration, and time-weighted average. The area below 75 mmHg represents the severity and duration of exposure and was defined as the sum of all areas below a specified threshold using the trapezoid rule. Time-weighted average MAP was derived by dividing area below the threshold by the duration of anesthesia. All analyses were adjusted for baseline risk factors including age greater than 70 years, female sex, severity of intracerebral hemorrhage, history of cardiovascular disease, and preoperative elevated myocardial enzymes.

RESULTS

Among 1029 patients enrolled, 254 (25%) developed postoperative MACE. Patients who experienced MACE were slightly older (59±11 vs. 54±11 years), were slightly more often women (69 vs. 58%), and had a higher prevalence of cardiovascular history (65 vs. 47%). Adjusted cardiovascular risk increased nearly linearly over the entire range of observed MAP. However, there was a slight inflexion at MAP of 75 mmHg. MACE was significantly associated with area [adjusted odds ratios (aOR) 1.004 per 10 mmHg.min, 95% CI: 1.001-1.007, P =0.002), duration (aOR 1.031 per 10 min, 95% CI: 1.009-1.054, P =0.006), and time-weighted average (aOR 3.516 per 10 mmHg, 95% CI: 1.818-6.801, P <0.001) of MAP less than 75 mmHg.

CONCLUSIONS

Lower blood pressures were associated with cardiovascular complications over the entire observed range, but worsened when MAP was less than 75 mmHg. Pending trial data to establish causality, it may be prudent to keep MAP above 75 mmHg in patients having surgical aSAH repairs to reduce the risk of MACE.

Effects of phenylephrine on systemic and cerebral circulations in humans: a systematic review with mechanistic explanations

We conducted a systematic review of the literature reporting phenylephrine-induced changes in blood pressure, cardiac output, cerebral blood flow and cerebral tissue oxygen saturation as measured by near-infrared spectroscopy in humans. We used the proportion change of the group mean values reported by the original studies in our analysis. Phenylephrine elevates blood pressure whilst concurrently inducing a reduction in cardiac output. Furthermore, despite increasing cerebral blood flow, it decreases cerebral tissue oxygen saturation. The extent of phenylephrine's influence on cardiac output (r = -0.54 and p = 0.09 in awake humans; r = -0.55 and p = 0.007 in anaesthetised humans), cerebral blood flow (r = 0.65 and p = 0.002 in awake humans; r = 0.80 and p = 0.003 in anaesthetised humans) and cerebral tissue oxygen saturation (r = -0.72 and p = 0.03 in awake humans; r = -0.24 and p = 0.48 in anaesthetised humans) appears closely linked to the magnitude of phenylephrine-induced blood pressure changes. When comparing the effects of phenylephrine in awake and anaesthetised humans, we found no evidence of a significant difference in cardiac output, cerebral blood flow or cerebral tissue oxygen saturation. There was also no evidence of a significant difference in effect on systemic and cerebral circulations whether phenylephrine was given by bolus or infusion. We explore the underlying mechanisms driving the phenylephrine-induced cardiac output reduction, cerebral blood flow increase and cerebral tissue oxygen saturation decrease. Individualised treatment approaches, close monitoring and consideration of potential risks and benefits remain vital to the safe and effective use of phenylephrine in acute care.

Postoperative arterial hypotension: the unnoticed enemy

Postoperative hypotension is a frequently underestimated health problem associated with high morbidity and mortality and increased use of health care resources. It also poses significant clinical, technological, and human challenges for healthcare. As it is a modifiable and avoidable risk factor, this document aims to increase its visibility, defining its clinical impact and the technological challenges involved in optimizing its management, taking clinical-technological, humanistic, and economic aspects into account.

Association of infraclavicular axillary vein diameter and collapsibility index with general anesthesia-induced hypotension in elderly patients undergoing gastrointestinal surgery: an observational study

BACKGROUND

The collapse index of inferior Vena Cava (IVC) and its diameter are important predictive tools for fluid responsiveness in patients, especially critically ones. The collapsibility of infraclavicular axillary vein (AXV) can be used as an alternative to the collapsibility of IVC (IVC-CI) to assess the patient's blood volume.

METHODS

A total of 188 elderly patients aged between 65 and 85 years were recruited for gastrointestinal surgery under general anesthesia. Ultrasound measurements AXV and IVC were performed before induction of general anesthesia. Patients were grouped in accordance to the hypotension after induction. ROC curves were used to analyze the predictive value of ultrasound measurements of AXV and IVC for hypotension after induction of anesthesia. Pearson linear correlation was used to assess the correlation of ultrasound measurements and decrease in mean arterial blood pressure (MAP).

RESULTS

The maximum diameter of AXV(dAXVmax) and the maximum diameter of IVC (dIVCmax) were not related to the percentage decrease in MAP; the collapsibility of AXV (AXV-CI) and IVC-CI were positively correlated with MAP changes (correlation coefficients:0.475, 0.577, respectively, p < 0.001). The areas under the curve (AUC) was 0.824 (0.759-0.889) for AXV-CI, and 0.874 (0.820-0.928) for IVC-CI. The optimal threshold for AXV-CI was 31.25% (sensitivity 71.7%, specificity 90.1%), while for IVC-CI was 36.60% (sensitivity 85.9%, specificity 79.0%). Hypotension and down-regulation of MAP during induction can be accurately predicted by AXV-Cl after correction for confounding variables.

CONCLUSION

Infraclavicular axillary vein diameter has no significant correlation with postanesthesia hypotension, whereas AXV-CI may predict postanesthesia hypotension during gastrointestinal surgery of the elderly.

TRIAL REGISTRATION

This study was registered in the Clinical Trial Registry of China on 05/06/2022 (ChiCTR2200060596).

End-Organ Damage in Hypertension: An Insight on a Differentiated Outpatient Consultation

OBJECTIVE

The objective of this study was to determine the prevalence of end-organ damage in hypertensive patients attending an outpatient consultation.

MATERIALS AND METHODS

Patients were selected from an outpatient consultation at a tertiary hospital care center. All patients who consulted between July 2022 and March 2023 were included. Data on demographic characteristics, blood pressure records, hypertension etiology, medication use, and the presence of target organ damage were collected.

RESULTS

A total of 73 patients were included in the study, with 34 patients being male (46.6%) and 39 patients being female (53.4%). The mean age of the patients was 49.8 years. Among the cases of hypertension, 14 (19.2%) were classified as secondary arterial hypertension (AH). The most common cause of secondary AH was obstructive sleep apnea (OSA) (42.9%). Approximately 23.2% of patients had documented end-organ damage potentially related to hypertension, with kidney disease being the most frequent (n = 10, 13.7%). The most commonly prescribed pharmacological classes were angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists (n = 46, 63%).

CONCLUSION

Despite numerous studies and trials on arterial hypertension, it remains a significant contributor to morbidity and mortality, necessitating the continued awareness of its long-term implications.

Predicting intraoperative hypotension: from hope to hype and back to reality

The analysis of arterial pressure waveforms with machine learning algorithms has been proposed to predict intraoperative hypotension. The ability to forecast arterial hypotension 5-15 min ahead of the fall in blood pressure allows clinicians to be pro-active instead of reactive, and could potentially decrease postoperative morbidity. However, the predictive value of machine learning algorithms has been overestimated due to selection bias in several clinical studies, and they might not be superior to mere observation of arterial pressure. Continuous blood pressure monitoring enables immediate detection of hypotension, and giving fluid, vasopressors or inotropes to patients who are not yet (and might never become) hypotensive based on an algorithm is questionable. Finally, recent prospective interventional studies suggest that reducing intraoperative hypotension does not improve postoperative outcomes.

Non-invasive arterial blood pressure measurement and SpO2 estimation using PPG signal: a deep learning framework

BACKGROUND

Monitoring blood pressure and peripheral capillary oxygen saturation plays a crucial role in healthcare management for patients with chronic diseases, especially hypertension and vascular disease. However, current blood pressure measurement methods have intrinsic limitations; for instance, arterial blood pressure is measured by inserting a catheter in the artery causing discomfort and infection.

METHOD

Photoplethysmogram (PPG) signals can be collected via non-invasive devices, and therefore have stimulated researchers' interest in exploring blood pressure estimation using machine learning and PPG signals as a non-invasive alternative. In this paper, we propose a Transformer-based deep learning architecture that utilizes PPG signals to conduct a personalized estimation of arterial systolic blood pressure, arterial diastolic blood pressure, and oxygen saturation.

RESULTS

The proposed method was evaluated with a subset of 1,732 subjects from the publicly available ICU dataset MIMIC III. The mean absolute error is 2.52 ± 2.43 mmHg for systolic blood pressure, 1.37 ± 1.89 mmHg for diastolic blood pressure, and 0.58 ± 0.79% for oxygen saturation, which satisfies the requirements of the Association of Advancement of Medical Instrumentation standard and achieve grades A for the British Hypertension Society standard.

CONCLUSIONS

The results indicate that our model meets clinical standards and could potentially boost the accuracy of blood pressure and oxygen saturation measurement to deliver high-quality healthcare.

Severe fluctuation in mean perfusion pressure is associated with increased risk of in-hospital mortality in critically ill patients with central venous pressure monitoring: A retrospective observational study

BACKGROUND

The mean perfusion pressure (MPP) was recently proposed to personalize tissue perfusion pressure management in critically ill patients. Severe fluctuation in MPP may be associated with adverse outcomes. We sought to determine if higher MPP variability was correlated with increased mortality in critically ill patients with CVP monitoring.

METHODS

We designed a retrospective observational study and analyzed data stored in the eICU Collaborative Research Database. Validation test was conducted in MIMIC-III database. The exposure was the coefficient of variation (CV) of MPP in the primary analyses, using the first 24 hours MPP data recorded within 72 hours in the first ICU stay. Primary endpoint was in-hospital mortality.

RESULTS

A total of 6,111 patients were included. The in-hospital mortality of 17.6% and the median MPP-CV was 12.3%. Non-survivors had significantly higher MPP-CV than survivors (13.0% vs 12.2%, p<0.001). After accounting for confounders, the highest MPP-CV in decile (CV > 19.2%) were associated with increased risk of hospital mortality compared with those in the fifth and sixth decile (adjusted OR: 1.38, 95% Cl: 1.07-1.78). These relationships remained remarkable in the multiple sensitivity analyses. The validation test with 4,153 individuals also confirmed the results when MPP-CV > 21.3% (adjusted OR: 1.46, 95% Cl: 1.05-2.03).

CONCLUSIONS

Severe fluctuation in MPP was associated with increased short-term mortality in critically ill patients with CVP monitoring.

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.