Blood Pressure Targets in Perioperative Care

Perioperative Management of Patients with Preeclampsia: A Comprehensive Review

Preeclampsia is a common condition of pregnancy characterized by hypertension complicated by cerebral, cardiac, hepatic, renal, hematologic, and placental dysfunction. Patients with preeclampsia frequently undergo cesarean delivery, the most common major surgical procedure in the world. They represent a high-risk perioperative cohort suffering significant preventable morbidity and mortality. This review focuses on the anesthesiologist's role, through a perioperative lens, in reducing maternal complications through management of hypertension and strategies for preserving the function of the brain, heart, liver, kidney, hematologic and coagulation systems, and placenta in patients with preeclampsia undergoing cesarean delivery. Preeclampsia-specific resuscitation, individualized fluid administration, safe neuraxial and general anesthesia, and management of intraoperative bleeding are discussed along with strategies for postoperative analgesia, thromboprophylaxis, and antihypertensive agents in patients who breastfeed. This review discusses recently recognized postoperative deterioration in maternal mental health, the possibility of myocardial injury after cesarean delivery, and the need for long-term cardiometabolic follow-up.

Diagnostic and therapeutic challenges in implementing hypertension management after kidney transplantation

PURPOSE OF REVIEW

Evidence for blood pressure (BP) measurement and hypertension management in kidney transplant recipients (KTR) remains lacking.

RECENT FINDINGS

Accurate BP measurement technique is a critical component of hypertension management, and 24-h ambulatory BP monitoring remains the gold standard for diagnosis of hypertension in KTR. BP target at different periods posttransplant is uncertain, but likely higher than that in nontransplant patients given factors related to long-standing uremic milieu and kidney transplantation such as vascular calcification altering transplant renal hemodynamic and allograft perfusion and immunosuppression. Dividing BP target into immediate, early, and late posttransplant periods can guide differential diagnoses of hypertension and BP control with a target SBP less than 160 mmHg in general and BP 115-135/65-85 mmHg for adult KTR receiving pediatric kidneys during the immediate posttransplant period, 130/80 mmHg during early and late posttransplant periods. Calcium channel blockers were shown to have favorable graft outcomes. Novel antihypertensive medications for resistant and refractory hypertension and device-based therapies are limited due to KTR's ineligibility for participating in clinical trials.

SUMMARY

In KTR, BP measurement and monitoring practice should follow the standard clinical practice guideline for nontransplant patients by considering posttransplant factors and immunosuppressive state. Novel treatment options required further studies.

Abnormal Autonomic Nervous Regulation in Patients with Globus Pharyngeus

BACKGROUND

Globus pharyngeus could be described as a benign sensation of lump or foreign object in the throat. The etiology of the globus as a solitary syndrome is still unknown, but it is proposed that stress could have an important role in symptom emergence.

AIMS

To evaluate the autonomic nervous regulation in patients with globus compared to healthy controls in reaction to stress.

METHODS

Patients included in the study were diagnosed based on ROME IV criteria for Disorders of Gut Brain Interaction. Besides globus, the patients did not suffer any other substantial medical condition. As a control group, measurement of healthy volunteers was performed. Both groups underwent the same stress protocol assessment in the same laboratory settings. The protocol consist of two types of stressors: cold pressor test and mental arithmetic test to test different types of autonomic reactivity.

RESULTS

Baroreflex sensitivity was significantly decreased in patients compared to controls in all phases of the protocol. Low-frequency band of systolic blood pressure variability was significantly increased during both stress phases in patients compared to controls. High-frequency band of heart rate variability was significantly decreased in patients compared to controls during the both of the stress phases.

CONCLUSION

The results of this study shows discrete abnormalities in complex autonomic reflex control which are predominantly manifested in response to stressful stimuli indicating altered neurocardiac regulation as a reaction to stress associated with globus pharynegus. This fact could have an important role in the personalized management of globus patients such as biofeedback.

Effects of Using Virtual Reality Technology on Pain and Hemodynamic Variables in Patients Receiving Hand Laceration Repair in an Emergency Department: A Randomized Controlled Trial

BACKGROUND

Pain and altered hemodynamic variables are among the most common complications in patients undergoing hand laceration repair in an Emergency Department.

AIM

This study aimed to evaluate the effects of using virtual reality (VR) technology on pain and hemodynamic variables in patients receiving hand laceration repair in an Emergency Department.

METHOD

This nonblinded randomized clinical trial included 160 patients undergoing laceration repair to their hands under local anesthetics from November 2020 to May 2021. The participants were randomly allocated to the experimental and control groups. Patients in the control group received routine care (such as ambient noise reduction, providing explanations about the surgery, and Lidocaine injection before the surgery). In the experimental group, a video containing natural landscapes and sounds was played using a semi-immersive VR headset during the surgery. Pain level and hemodynamic variables were measured immediately before and after the intervention. The pain was measured using the Critical Care Pain Observation Tool and Visual Analog Scale.

RESULTS

Immediately after the intervention, systolic blood pressure (BP), respiration rate, and pain intensity were significantly lower in the intervention group compared with the control group (p < .05). There were no significant differences between the intervention and control groups regarding diastolic BP, mean BP, SPO2, heart rate, and muscular tension (p > .05).

CONCLUSIONS

Semi-immersive VR is effective in managing pain and hemodynamic variables during hand laceration repair. The nurses could use the semi-immersive VR to better control of pain and hemodynamic variables during hand laceration repair.

Insights Into Perioperative Hypertension Management in Europe: Results From a Survey Endorsed by the European Association of Cardiothoracic Anaesthesiology and Intensive Care (EACTAIC)

OBJECTIVES

Perioperative blood pressure control is crucial to ensure organ perfusion and avoid adverse events. However, no consensus on blood pressure targets is available. This study was designed to gain insights into current European perioperative hypertension management practices.

DESIGN

Survey research.

SETTING

Online survey.

PARTICIPANTS

The survey was administered to members of the European Association of Cardiothoracic Anaesthesiology and Intensive Care and distributed through the organization's social media.

INTERVENTIONS

A 22-item questionnaire on the approach to perioperative hypertension control and its pharmacological management.

MEASUREMENTS AND MAIN RESULTS

The study included surveys completed between July 1 and October 30, 2023. In total, 339 participants completed the questionnaire; 70% were anesthesiologists, 17% were intensive care physicians, and 12% were cardiac surgeons.

MAJOR FINDINGS

More than 50% of respondents declared dealing with perioperative hypertension in 20% to 50% of their surgeries, and most target the 120 to 140 mmHg systolic blood pressure (SBP) range during surgery. Respondents mostly rely on α-adrenoreceptor antagonists (29%), nitrates (23%), and calcium channel blockers (15%) to manage perioperative hypertension. Titratable control was the most appreciated attribute of intravenous antihypertensives. Antihypertensive treatment failure occurred in less than 20% of surgeries, and the highest risk of hypotensive episodes was perceived by participants to be when using nitroglycerin and nitroprusside.

CONCLUSIONS

Perioperative SBP targets above 140 mmHg are uncommon among respondents, who predominantly target SBP values between 120 and 140 mmHg. The choice of intravenous antihypertensives is based on their manageability and user experience, and titratable control is the most appreciated characteristic.

Outpatient Total Joint Arthroplasty at an Ambulatory Surgical Center: An Analysis of Failure to Launch

BACKGROUND

There has been a tremendous increase in same-day discharge (SDD) following primary total joint arthroplasty (TJA). Although the concept of failure to launch (FTL) has been recently investigated in hospital settings, there is a paucity of data in the ambulatory surgical center (ASC) context. This study aimed to examine the incidence and underlying causes of FTL within an ASC at a major academic medical center.

METHODS

A retrospective review from 2021 to 2024 was performed on all patients who underwent same-day surgery at our ASC after intentional selection and medical optimization per institutional protocols. The demographic information, incidence and source of FTL, 90-day readmissions, and reoperations/revisions were recorded. There were 1,974 patients who underwent primary TJA at the ASC during the study.

RESULTS

There were nine patients who required direct hospital admission from the ASC (0.45%). This patient population had significantly increased American Society of Anesthesiologists score compared to patients who were discharged home. In addition, these patients had a significantly higher number of 90-day emergency department visits. Syncopal episodes were the most common reason for hospital admission from the ASC (66.7%), followed by nausea, seizures, and pain (all 11.1%). After review by attending orthopaedic surgeons and anesthesiologists, only two patients had potentially preventable medical causes for admission.

CONCLUSIONS

Approximately, 99.6% of patients had successful SDD at our ASC, underscoring the importance of proper preoperative screening. Only 0.45% of patients required hospital admission, primarily attributed to hypotension and syncopal events. Interestingly, only two patients in our cohort experienced a potentially preventable instance of FTL. It is crucial that additional efforts be aimed at identifying patients at risk and implementing treatment strategies to prevent postoperative hypotension and syncopal events that may further improve SDD and outcomes in outpatient TJA in the ASC setting.

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).

Risk Factors and Clinical Outcomes of Perioperative Hypotension in the Neck of Femur Fracture Surgery: A Case-Control and Cohort Analysis

Introduction Neck-of-femur (NOF) fractures have high prevalence rates and require prompt surgical intervention for better outcomes. Perioperative hypotension (POH) in the geriatric population has poor outcomes with several contributing factors. The study intends to explore these risk factors and their correlation with patient outcomes.  Methodology We studied a total of 276 patients who underwent surgical fixation of the NOF fracture at St Peter's Hospital, Surrey, from June 1, 2022, to June 1, 2023. Patients with POH were identified; the risk factors and one-year outcome were studied to obtain the results. We used odds ratio (OR), relative risk (RR), and multivariate regression to analyse the statistical association within the data. Results The incidence of POH was 68% (188/276) which included preoperative hypotension (9.78%), intraoperative hypotension (48.55%), and postoperative hypotension with a mean arterial pressure (MAP) of <65 mmHg (24.63%) and fall of systolic blood pressure to less than 80% (34.42%). Statistically significant risk factors were hypertension (OR: 1.330), heart disease (OR: 2.768), and hemoglobin (Hg) drop (OR: 1.42). The outcomes we studied were all statistically significant, with an RR of more than one. It includes postoperative delirium (RR: 2.037), postoperative 30-day morbidity (RR: 4.008), postoperative 30-day mortality (RR: 6.12), 365-day mortality (RR: 2.224), postoperative delay in mobilisation (RR: 1.329), and prolonged length of stay (RR: 1.273).  Conclusion The study shows a clear association between POH and increased postoperative complications, highlighting the need for prompt intervention. This case-control study identified hypertension, history of heart disease, and perioperative blood loss as significant risk factors for developing POH. Also, this study demonstrates that POH is significantly associated with adverse outcomes, including the increased risk of delirium, prolonged hospital stays, and elevated 30-day morbidity in elderly patients undergoing hip fracture surgery. The findings also indicated that the duration of hypotension did not directly influence the outcomes; its occurrence alone is a significant factor in developing these complications.

Dynamic Estimation of Cardiovascular State From Arterial Blood Pressure Recordings

Real-time estimation of patient cardiovascular states, including cardiac output and systemic vascular resistance, is necessary for personalized hemodynamic monitoring and management. Highly invasive measurements enable reliable estimation of these states but increase patient risk. Prior methods using minimally invasive measurements reduce patient risk but have produced unreliable estimates limited due to trade-offs in accuracy and time resolution. Our objective was to develop an approach to estimate cardiac output and systemic vascular resistance with both a high time resolution and high accuracy from minimally invasive measurements. Using the two-element Windkessel model, we formulated a state-space method to estimate a dynamic time constant - the product of systemic vascular resistance and compliance - from arterial blood pressure measurements. From this time constant, we derived proportional estimates of systemic vascular resistance and cardiac output. We then validated our method with a swine cardiovascular dataset. Our estimates produced using arterial blood pressure measurements not only closely align with those using highly invasive measurements, but also closely align when derived from three separate locations on the arterial tree. Moreover, our estimates predictably change in response to standard cardiovascular drugs. Overall, our approach produces reliable, real-time estimates of cardiovascular states crucial for monitoring and control of the cardiovascular system.

Energy barriers govern catheter herniation during endovascular procedures: a 2.5D vascular flow model analysis

Endovascular procedures rely on navigating guidewires, catheters and other devices through tortuous vasculature to treat disease. A critical challenge in these procedures is catheter herniation, in which the device deviates from its intended path, often irrecoverably. To elucidate the mechanics of herniation, we developed a physical flow model of the aortic arch that enables direct measurement of device curvature during experimentally simulated neuroendovascular procedures conducted from an upper arterial access. Combined with measurements of initial, unstressed device shapes and flexural rigidities, the method enables the experimental estimation of the device bending energies during these simulated procedures. Characteristic energy profiles revealed distinct stages in both herniation and successful navigation, governed by the interplay between device properties and vascular anatomy. A deterministic progression from successful navigation to herniation was identified, with catheter systems following paths determined by measurable energy barriers. Increasing guidewire stiffness or decreasing catheter stiffness reduced the energy barrier for successful navigation while increasing that for herniation. This framework enables the prediction of endovascular herniation risk and offers unique insight into improved device design and clinical decision-making.

Laparoscopic cholecystectomy in a patient with Fontan circulation

BACKGROUND

Fontan circulation is created when a baby is born with only one functioning cardiac ventricle. A series of surgeries are performed to allow the ventricle to provide oxygenated blood to the systemic circulation and to create passive flow of venous blood to the pulmonary circulation via a conduit. Laparoscopic surgery poses several hemodynamic challenges to a patient with Fontan physiology attributable to carbon dioxide insufflation, positive pressure ventilation, and reverse Trendelenburg positioning.

CLINICAL FEATURES

A 39-yr-old male with a Fontan physiology was referred to our tertiary care centre because of repeated bouts of cholecystitis requiring a percutaneous drain and now elective laparoscopic cholecystectomy. Because of repeated cardiac surgeries, the patient also had complete heart block and was pacemaker dependent. We placed an arterial catheter prior to induction of general anesthesia with tracheal intubation. Transesophageal echocardiography allowed for real-time intraoperative assessment of venous blood flow through the patient's extracardiac diversion system throughout the surgery. This information was used to guide management and determine circulation tolerance during the various stages of laparoscopy. Inhaled milrinone resulted in the shunt fraction returning to the patient's baseline. Intraperitoneal pressure was kept below 10 mm Hg, and systemic blood pressure was supported with a low-dose norepinephrine infusion.

CONCLUSIONS

Intraoperative transesophageal echocardiography is a useful monitoring device during laparoscopic surgery when a patient has Fontan circulation. Knowing how to administer inhaled milrinone is a useful skill to decrease the shunt fraction through a patient's conduit, increasing pulmonary blood flow while avoiding hypotension.

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.

Intraoperative hypotension associated with postoperative acute kidney injury in hypertension patients undergoing non-cardiac surgery: a retrospective cohort study

Background

Acute kidney injury (AKI) is a common surgical complication and is associated with intraoperative hypotension. However, the total duration and magnitude of intraoperative hypotension associated with AKI remains unknown. In this study, the causal relationship between the intraoperative arterial pressure and postoperative AKI was investigated among chronic hypertension patients undergoing non-cardiac surgery.

Methods

A retrospective cohort study of 6552 hypertension patients undergoing non-cardiac surgery (2011 to 2019) was conducted. The primary outcome was AKI as diagnosed with the Kidney Disease-Improving Global Outcomes criteria and the primary exposure was intraoperative hypotension. Patients' baseline demographics, pre- and post-operative data were harvested and then analyzed with multivariable logistic regression to assess the exposure-outcome relationship.

Results

Among 6552 hypertension patients, 579 (8.84%) had postoperative AKI after non-cardiac surgery. The proportions of patients admitted to ICU (3.97 vs. 1.24%, p < 0.001) and experiencing all-cause death (2.76 vs. 0.80%, p < 0.001) were higher in the patients with postoperative AKI. Moreover, the patients with postoperative AKI had longer hospital stays (13.50 vs. 12.00 days, p < 0.001). Intraoperative mean arterial pressure (MAP) < 60 mmHg for >20 min was an independent risk factor of postoperative AKI. Furthermore, MAP <60 mmHg for >10 min was also an independent risk factor of postoperative AKI in patients whose MAP was measured invasively in the subgroup analysis.

Conclusions

Our work suggested that MAP < 60 mmHg for >10 min measured invasively or 20 min measured non-invasively during non-cardiac surgery may be the threshold of postoperative AKI development in hypertension patients. This work may serve as a perioperative management guide for chronic hypertension patients.

Trial registration

clinical trial number: ChiCTR2100050209 (8/22/2021). http://www.chictr.org.cn/showproj.aspx?proj=132277.

Endobronchial Phenylephrine in Airway Bleeding During Bronchoscopy Does not Cause Hypertension: A Retrospective Observational Study

BACKGROUND

Bleeding is a known complication during bronchoscopy, with increased incidence in patients undergoing a more invasive procedure. Phenylephrine is a potent vasoconstrictor that can control airway bleeding when applied topically and has been used as an alternative to epinephrine. The clinical effects of endobronchial phenylephrine on systemic vasoconstriction have not been clearly evaluated. Here, we compared the effects of endobronchial phenylephrine versus cold saline on systemic blood pressure.

METHODS

In all, 160 patients who underwent bronchoscopy and received either endobronchial phenylephrine or cold saline from July 1, 2017 to June 30, 2022 were included in this retrospective observational study. Intra-procedural blood pressure absolute and percent changes were measured and compared between the 2 groups.

RESULTS

There were no observed statistical differences in blood pressure changes between groups. The median absolute change between the median and the maximum intra-procedural systolic blood pressure in the cold saline group was 29 mm Hg (IQR 19 to 41) compared with 31.8 mm Hg (IQR 18 to 45.5) in the phenylephrine group. The corresponding median percent changes in SBP were 33.6 % (IQR 18.8 to 39.4) and 28% (IQR 16.8 to 43.5) for the cold saline and phenylephrine groups, respectively. Similarly, there were no statistically significant differences in diastolic and mean arterial blood pressure changes between both groups.

CONCLUSIONS

We found no significant differences in median intra-procedural systemic blood pressure changes comparing patients who received endobronchial cold saline to those receiving phenylephrine. Overall, this argues for the vascular and systemic safety of phenylephrine for airway bleeding as a reasonable alternative to epinephrine.

Development of a Probabilistic Boolean network (PBN) to model intraoperative blood pressure management

BACKGROUND

Blood pressure is a vital sign for organ perfusion that anesthesiologists measure and modulate during surgery. However, current decision-making processes rely heavily on clinicians' experience, which can lead to variability in treatment across surgeries. With the advent of machine learning, we can now create models to predict the outcomes of interventions and guide perioperative decision-making. The first step in this process involves translating the clinical decision-making process into a framework understood by an algorithm. Probabilistic Boolean networks (PBNs) provide an information-rich approach to this problem. A PBN trends toward a steady state, and its decisions are easily understood via its Boolean predictor functions. We hypothesize that a PBN can be developed that corrects hemodynamic instability in patients by selecting clinical interventions to maintain blood pressure within a given range.

METHODS

Data on patients over the age of 65 undergoing surgery with general anesthesia from 2018 to 2020 were drawn from the UF Health PRECEDE data set with IRB approval (IRB201700747). Parameters examined included heart rate, blood pressure, and frequency of medications given 15 min after anesthetic induction and 15 min before awakening. The medication frequency data were truncated into a 66/33 split for the training and validation set used in the PBN. The model was coded using Python 3 and evaluated by comparing the frequency of medications chosen by the program to the values in the testing set via linear regression analysis.

RESULTS

The network developed successfully models a hemodynamically unstable patient and corrects the imbalance by administering medications. This is evidenced by the model achieving a stable, steady state matrix in all iterations. However, the model's ability to emulate clinical drug selection was variable. It was successful with its use of vasodilator selection but struggled with the appropriate selection of vasopressors.

CONCLUSIONS

The PBN has demonstrated the ability to choose appropriate interventions based on a patient's current vitals. Additional work must be done to have the network emulate the frequency at which drugs are selected from in clinical practice. In its current state, the model provides an understanding of how a PBN behaves in the context of correcting hemodynamic instability and can aid in developing more robust models in the future.

Influence of gestational hypertension and maternal air pollutant exposure on birth outcomes

The relationship between exposure to air pollutants and fetal growth outcomes has shown inconsistency, and only a limited number of studies have explored the impact of air pollution on gestational hypertension and birth outcomes. This study aimed to evaluate how maternal exposure to air pollutants and blood pressure could influence fetal birth outcomes. A total of 55 women with gestational hypertension and 131 healthy pregnant women were enrolled in this study. Data pertaining to personal characteristics, prenatal examinations, outdoor air pollutant exposure, and fetal birth outcomes were collected. The study revealed that fetal birth weight and abdominal circumference exhibited a significant reduction among women with gestational hypertension compared to healthy pregnant women, even after adjustments for body mass index, gestational age, and exposure to air pollutants had been made. Moreover, maternal exposure to outdoor air pollutants displayed a notable correlation with decreased birth length of fetuses. Consequently, the study concluded that maternal blood pressure and exposure to outdoor air pollutants during pregnancy potentially stand as pivotal factors influencing fetal birth outcomes.

Hemodynamic effects of withholding vs. continuing angiotensin II receptor blockers on the day of prone positioning spinal surgery in elderly patients

Introduction

The hemodynamic effects of withholding vs. continuing angiotensin II receptor blockers (ARBs) before surgery in elderly patients undergoing spinal surgery in a prone position during anesthesia induction to skin incision are still unknown.

Methods

In this prospective study, 80 patients undergoing spinal surgery in a prone position with general anesthesia, aged 60-79 years, American Society of Anesthesiologists (ASA) II or III, were enrolled. Patients who had ARBs only in their preoperative medication list were randomly divided into two groups at a 1:1 ratio: In Group A, ARBs were continued on the morning of surgery, while in Group B, they were withhold. Norepinephrine was infused to maintain the blood pressure at the baseline level of ±20% during anesthesia induction in all patients. The primary outcome was the consumption of norepinephrine in each group from anesthesia induction to skin incision. The secondary outcomes include changes in invasive arterial blood pressure and heart rate, the fluid infusion volumes, the amounts of anesthetic drugs, and the total time from induction to skin incision.

Results

There were no significant differences in the demographics, the fluid infusion volumes, the amounts of anesthetic drugs, the total time from induction to skin incision, and hemodynamics at different time points (p > 0.05), while significant differences were found in norepinephrine consumption between the two groups (p < 0.001). Compared with Group B, the consumption of norepinephrine increased significantly in Group A (93.3 ± 29.8 vs. 124.1 ± 38.7 μg, p = 0.000). In addition, the same trend was illustrated in the pumping rate of norepinephrine between Group B (0.04 ± 0.01 μg·kg-1·min-1) and Group A (0.06 ± 0.02 μg·kg-1·min-1) (p = 0.004).

Conclusion

Our study conducted in elderly patients with hypotension undergoing prone spinal surgery demonstrated a greater pumping rate of norepinephrine during anesthesia induction in patients with ARBs continuing before surgery than those withholding, indicating that it was more difficult to maintain hemodynamic stability.Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=141081, ChiCTR2100053583.

Effect of using hypotension prediction index versus conventional goal-directed haemodynamic management to reduce intraoperative hypotension in non-cardiac surgery: A randomised controlled trial

STUDY OBJECTIVE

It remains unclear whether it is the hypotension prediction index itself or goal-directed haemodynamic therapy that mitigates intraoperative hypotension.

DESIGN

A single centre randomised controlled trial.

SETTING

Sapporo Medical University Hospital.

PATIENTS

A total of 64 adults patients undergoing major non-cardiac surgery under general anaesthesia.

INTERVENTIONS

Patients were randomly assigned to either group receiving conventional goal-directed therapy (FloTrac group) or combination of the hypotension prediction index and conventional goal-directed therapy (HPI group). To investigate the independent utility of the index, the peak rates of arterial pressure and dynamic arterial elastance were not included in the treatment algorithm for the HPI group.

MEASUREMENTS

The primary outcome was the time-weighted average of the areas under the threshold. Secondary outcomes were area under the threshold, the number of hypotension events, total duration of hypotension events, mean mean arterial pressure during the hypotension period, number of hypotension events with mean arterial pressure < 50 mmHg, amounts of fluids, blood products, blood loss, and urine output, frequency and amount of vasoactive agents, concentration of haemoglobin during the monitoring period, and 30-day mortality.

MAIN RESULTS

The time-weighted average of the area below the threshold was lower in the HPI group than in the control group; 0.19 mmHg (interquartile range, 0.06-0.80 mmHg) vs. 0.66 mmHg (0.28-1.67 mmHg), with a median difference of -0.41 mmHg (95% confidence interval, -0.69 to -0.10 mmHg), p = 0.005. Norepinephrine was administered to 12 (40%) and 5 (17%) patients in the HPI and FloTrac groups, respectively (p = 0.045). No significant differences were observed in the volumes of fluid and blood products between the study groups.

CONCLUSIONS

The current randomised controlled trial results suggest that using the hypotension prediction index independently lowered the cumulative amount of intraoperative hypotension during major non-cardiac surgery.

Evaluation of the Safety of Liberalized Systolic Blood Pressure Goals in the Postoperative Period After Intracranial Tumor Resection

BACKGROUND AND OBJECTIVES

Postoperative intracranial hemorrhage (POH) is a serious neurosurgical complication occurring in approximately 1.4% of patients after intracranial tumor resection. The convention across the United States is to maintain an immediate postoperative systolic blood pressure (SBP) of < 140 mm Hg to minimize this risk; however, this SBP goal lacks support in the literature despite widespread adoption. This study aims to investigate the safety of SBP liberalization to 160 mm Hg in the immediate postoperative setting after intracranial tumor resection.

METHODS

A retrospective review was conducted on consecutive patients, aged 18 to 75 years, undergoing craniotomy for intracranial tumor resection from October 2020 until June 2023. Data were gathered from the electronic medical record per Institutional Review Board guidelines regarding demographics, operative details, perioperative vital signs, resource utilization, and complications. Pharmaceutical prices and insurance charges were approximated from costs provided by the institution's pharmacy. POH was defined as symptomatic hemorrhage within 48 hours requiring intervention.

RESULTS

The study included 147 patients, with 104 in the liberalized cohort (SBP <160 mm Hg) and 43 in the standard cohort (SBP <140 mm Hg). The average age was 54.5 ± 14.9 years and 57.6 ± 10.6 years in the liberalized and standard groups, respectively (P = .23). Intensive care unit and hospital length of stay were not significantly different between groups. The liberalized group used $81.88 ± $280.19 (95% CI $53.01-$110.75) on as-needed antihypertensive medications vs $108.39 ± $215.91 (95% CI $75.96-$140.82) in the standard (P = .29), with significantly lower labetalol (P = .04). There was no POH in either cohort.

CONCLUSION

Liberalization of SBP goals to <160 mm Hg appears safe in the immediate postoperative period after craniotomy for tumor resection without an increased POH risk. Liberalized SBP parameters may allow reduced antihypertensive medication usage, thereby avoiding excess hospital cost and medication side effects.

Management of Inpatient Elevated Blood Pressures : A Systematic Review of Clinical Practice Guidelines

BACKGROUND

Management of elevated blood pressure (BP) during hospitalization varies widely, with many hospitalized adults experiencing BPs higher than those recommended for the outpatient setting.

PURPOSE

To systematically identify guidelines on elevated BP management in the hospital.

DATA SOURCES

MEDLINE, Guidelines International Network, and specialty society websites from 1 January 2010 to 29 January 2024.

STUDY SELECTION

Clinical practice guidelines pertaining to BP management for the adult and older adult populations in ambulatory, emergency department, and inpatient settings.

DATA EXTRACTION

Two authors independently screened articles, assessed quality, and extracted data. Disagreements were resolved via consensus. Recommendations on treatment targets, preferred antihypertensive classes, and follow-up were collected for ambulatory and inpatient settings.

DATA SYNTHESIS

Fourteen clinical practice guidelines met inclusion criteria (11 were assessed as high-quality per the AGREE II [Appraisal of Guidelines for Research & Evaluation II] instrument), 11 provided broad BP management recommendations, and 1 each was specific to the emergency department setting, older adults, and hypertensive crises. No guidelines provided goals for inpatient BP or recommendations for managing asymptomatic moderately elevated BP in the hospital. Six guidelines defined hypertensive urgency as BP above 180/120 mm Hg, with hypertensive emergencies requiring the addition of target organ damage. Hypertensive emergency recommendations consistently included use of intravenous antihypertensives in intensive care settings. Recommendations for managing hypertensive urgencies were inconsistent, from expert consensus, and focused on the emergency department. Outpatient treatment with oral medications and follow-up in days to weeks were most often advised. In contrast, outpatient BP goals were clearly defined, varying between 130/80 and 140/90 mm Hg.

LIMITATION

Exclusion of non-English-language guidelines and guidelines specific to subpopulations.

CONCLUSION

Despite general consensus on outpatient BP management, guidance on inpatient management of elevated BP without symptoms is lacking, which may contribute to variable practice patterns.

PRIMARY FUNDING SOURCE

National Institute on Aging. (PROSPERO: CRD42023449250).

Incidence of intraoperative hypotension and its factors among adult traumatic head injury patients in comprehensive specialized hospitals, Northwest Ethiopia: a multicenter observational study

INTRODUCTION

Traumatic head injury (THI) poses a significant global public health burden, often contributing to mortality and disability. Intraoperative hypotension (IH) during emergency neurosurgery for THI can adversely affect perioperative outcomes, and understanding associated risk factors is essential for prevention.

METHOD

A multi-center observational study was conducted from February 10 to June 30, 2022. A simple random sampling technique was used to select the study participants. Patient data were analyzed using bivariate and multivariate logistic regression to identify significant factors associated with intraoperative hypotension (IH). Odds ratios with 95% confidence intervals were used to show the strength of association, and P value < 0.05 was considered as statistically significant.

RESULT

The incidence of intra-operative hypotension was 46.41% with 95%CI (39.2,53.6). The factors were duration of anesthesia ≥ 135 min with AOR: 4.25, 95% CI (1.004,17.98), severe GCS score with AOR: 7.23, 95% CI (1.098,47.67), intracranial hematoma size ≥ 15 mm with AOR: 7.69, 95% CI (1.18,50.05), and no pupillary abnormality with AOR: 0.061, 95% CI (0.005,0.732). CONCLUSION AND RECOMMENDATION: The incidence of intraoperative hypotension was considerably high. The duration of anesthesia, GCS score, hematoma size, and pupillary abnormalities were associated. The high incidence of IH underscores the need for careful preoperative neurological assessment, utilizing CT findings, vigilance for IH in patients at risk, and proactive management of IH during surgery. Further research should investigate specific mitigation strategies.

Preoperative Renin-Angiotensin System Antagonists Intake and Blood Pressure Responses During Ambulatory Surgical Procedures: A Prospective Cohort Study

BACKGROUND

There is limited evidence to inform the association between the intake of angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs) and intraoperative blood pressure (BP) changes in an ambulatory surgery population.

METHODS

Adult patients who underwent ambulatory surgery and were discharged on the same day or within 24 hours of their procedure were enrolled in this prospective cohort study. The primary outcome of the study was early intraoperative hypotension (first 15 minutes of induction). Secondary outcomes included any hypotension, BP variability, and recovery. Hypotension was defined as a decrease in systolic BP of >30% from baseline for ≥5 minutes or a mean BP of <55 mm Hg. Four exposure groups were compared (no antihypertensives, ACEI/ARB intake <10 hours before surgery, ACEI/ARB intake ≥10 hours before surgery, and other antihypertensives).

RESULTS

Of the 537 participants, early hypotension was observed in 25% (n = 134), and any hypotension in 41.5% (n = 223). Early hypotension occurred in 30% (29 of 98) and 41% (17 of 41) with the intake of ACEI/ARBs <10 and ≥10 hours before surgery, respectively, compared to 30% (9 of 30) with other antihypertensives and 21% (79 of 368) with no antihypertensives ( P = .02). Those on antihypertensives also experienced any hypotension more frequently than those who were not on antihypertensives ( P < .001). After adjusting for age and baseline BP in a regression analysis, antihypertensive exposure groups were observed to be associated only with any intraoperative hypotension ( P = .012). In the ACEI/ARB subset, there was no evidence of an association between time since the last ACEI/ARB dose, and hypotension or minimum mean or systolic BP. Compared to normal baseline BP, BP ≥ 140/90 mm Hg increased the odds of early and any hypotension (odds ratio [OR], 3.9; 95% confidence interval [CI], 2.1-7.1 and OR, 7.7; 95% CI, 3.7-14.9, respectively; P < .001). Intraoperative variability in systolic and diastolic BP demonstrated significant differences with age, baseline BP, and antihypertensive exposure group ( P < .001).

CONCLUSIONS

Early and any hypotension occurred more frequently in those on antihypertensives than those not on antihypertensives. Unadjusted associations between antihypertensive exposure and intraoperative hypotension were largely explained by baseline hypertension rather than the timing of ACEI/ARBs or type of antihypertensive exposure. Patients with hypertension and on treatment experience more intraoperative BP variability and should be monitored appropriately.

Cerebral Perfusion Unveiled: A Comprehensive Review of Blood Pressure Management in Neurosurgical and Endovascular Aneurysm Interventions

This comprehensive review delves into the intricate dynamics of cerebral perfusion and blood pressure management within the context of neurosurgical and endovascular aneurysm interventions. The review highlights the critical role of maintaining a delicate hemodynamic balance, given the brain's susceptibility to fluctuations in blood pressure. Emphasizing the regulatory mechanisms of cerebral perfusion, particularly autoregulation, the study advocates for a nuanced and personalized approach to blood pressure control. Key findings underscore the significance of adhering to tailored blood pressure targets to mitigate the risks of ischemic and hemorrhagic complications in both neurosurgical and endovascular procedures. The implications for clinical practice are profound, calling for heightened awareness and precision in hemodynamic management. The review concludes with recommendations for future research, urging exploration into optimal blood pressure targets, advancements in monitoring technologies, investigations into long-term outcomes, and the development of personalized approaches. By consolidating current knowledge and charting a path for future investigations, this review aims to contribute to the continual enhancement of patient outcomes in the dynamic field of neurovascular interventions.

Perioperative stroke

Ischaemic or haemorrhagic perioperative stroke (that is, stroke occurring during or within 30 days following surgery) can be a devastating complication following surgery. Incidence is reported in the 0.1-0.7% range in adults undergoing non-cardiac and non-neurological surgery, in the 1-5% range in patients undergoing cardiac surgery and in the 1-10% range following neurological surgery. However, higher rates have been reported when patients are actively assessed and in high-risk populations. Prognosis is significantly worse than stroke occurring in the community, with double the 30-day mortality, greater disability and diminished quality of life among survivors. Considering the annual volume of surgeries performed worldwide, perioperative stroke represents a substantial burden. Despite notable differences in aetiology, patient populations and clinical settings, existing clinical recommendations for perioperative stroke are extrapolated mainly from stroke in the community. Perioperative in-hospital stroke is unique with respect to the stroke occurring in other settings, and it is essential to apply evidence from other settings with caution and to identify existing knowledge gaps in order to effectively guide patient care and future research.

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.

ABO blood types may affect transient neurological events after surgical revascularization in patients with moyamoya disease: a retrospective single center study

BACKGROUND

Moyamoya disease (MMD) is a cerebrovascular disease with unknown cause. Patients with MMD disease usually experience transient neurological events (TNEs) after revascularization surgery. This retrospective single-center study was aimed to explore the risk factors of postoperative TNEs after surgical revascularization in patients with MMD.

METHODS

We selected 324 patients who underwent surgical revascularization between January 2017 and September 2022 in our center. The perioperative characteristics of the patients were recorded and the outcome was TNEs after surgery. An analysis of risk factors contributing to postoperative TNEs by using logistic regression model.

RESULTS

Three hundred twelve patients were enrolled, and the incidence of postoperative TNEs was 34% in our study. Males were more likely to suffer from postoperative TNEs (OR = 2.344, p = 0.002). Preoperative ischemic presentation (OR = 1.849, p = 0.048) and intraoperative hypotension (OR = 2.332, p = 0.002) were associated with postoperative TNEs. Compared to patients with blood type O, patients with blood type A (OR = 2.325, p = 0.028), B (OR = 2.239, p = 0.027) and AB (OR = 2.938, p = 0.019) had a significantly higher incidence of postoperative TNEs. A risk prediction model for postoperative TNEs was established, and the established risk prediction area under the receiver operating characteristic curve (ROC) of the model was 0.741.

CONCLUSIONS

Males, preoperative ischemic presentation and intraoperative hypotension were associated with postoperative TNEs. We also found a possible link between postoperative TNEs and ABO blood types after surgical revascularization for moyamoya patients.

Perioperative cardiac risk reduction in non cardiac surgery

For patients undergoing nonemergent noncardiac surgery, care must be taken to identify patients at increased risk of major adverse cardiovascular events, as these remain a significant source of perioperative morbidity and mortality. Identification of at-risk patients requires careful attention to risk factors including assessment of functional status, medical comorbidities, and a medication assessment. After identification, to minimize perioperative cardiac risk, care should be taken through a combination of appropriate medication management, close monitoring for cardiovascular ischemic events, and optimization of pre-existing medical conditions. There are multiple society guidelines that aim to mitigate risk of cardiovascular morbidity and mortality in patients undergoing nonemergent noncardiac surgery. However, the rapid evolution of medical literature often creates gaps between the existing evidence and best practice recommendations. In this review, we aim to reconcile the recommendations made in the guidelines from the major cardiovascular and anesthesiology societies from the USA, Canada, and Europe, and to provide updated recommendations based on new evidence.

Safety and efficacy of continuous intravenous labetalol for blood pressure control in neurosurgical patients

OBJECTIVES

Current evidence supporting the use of continuous intravenous labetalol for blood pressure (BP) control in neurosurgical patients is limited. This study aims to assess the efficacy and safety of labetalol in neurosurgical patients and identify potential contributing factors to these outcomes.

METHODS

We retrospectively reviewed the medical records of neurosurgical patients who received continuous labetalol infusion for BP control. Efficacy was assessed based on the time needed to achieve the target BP (systolic BP ≤ 140 mmHg or diastolic BP ≤ 90 mmHg). Safety was assessed according to adverse events that occurred during labetalol administration. Factors associated with efficacy and safety were analyzed using a logistic regression model.

RESULTS

Among 79 patients enrolled in this study, 47 (59.49%) achieved the target BP within 1 hour (early response). No factors were significantly associated with an early response. Hypotension was observed in 11 patients (13.9%), and bradycardia was observed in 8 patients (10.1%). Hypotension was significantly associated with patient age and motor impairment, while bradycardia was significantly associated with diabetes mellitus.

CONCLUSION

The efficacy and safety profiles of labetalol infusion suggest this treatment as a promising option for BP control in neurosurgical patients.

Clinical triggers and vital signs influencing crisis acknowledgment and calls for help by anesthesiologists: A simulation-based observational study

STUDY OBJECTIVE

In a perioperative emergency, anesthesiologists must acknowledge the unfolding crisis promptly, call for timely assistance, and avert patient harm. We aimed to identify vital signs and qualitative factors prompting crisis acknowledgment and to compare responses between observers and participants in simulation.

DESIGN

Prospective, simulation-based, observational study.

SETTING

An anesthesia crisis resource management course at a freestanding simulation center.

SUBJECTS

Sixty attending anesthesiologists from a variety of practice settings.

INTERVENTIONS

In each case, a primary anesthesiologist in charge (PAIC) managed a simulated patient undergoing a uniformly scripted sequence of perioperative anaphylaxis and called for help from another anesthesiologist when a crisis began. Anesthesiologist observers (AOs) viewed the case separately and recorded times of crisis onset.

MEASUREMENTS

Simulation footage was reviewed by investigators for patient vital signs and participant behaviors at times of crisis acknowledgment, with the call for help as an explicit proxy for PAIC crisis acknowledgment. These factors were categorized, and group-level data were compared.

RESULTS

Nineteen PAICs and 41 AOs were included. Clinicians acknowledged crises around a mean arterial pressure (MAP) of 65 mmHg and oxygen saturation of 94% as anaphylactic shock progressed. PAICs acknowledged crises at a higher respiratory rate than AOs (20 vs. 18 breaths/min, p = 0.038). Other vitals and timing of crisis acknowledgment did not differ between PAICs and AOs. Nearly half of all participants (45%) identified crises at MAP <65 mmHg. Timing of crisis acknowledgment varied widely (range: 421 s).

CONCLUSIONS

Despite overall heterogeneity in clinical performance, anesthesiologists acknowledged crises per standard definitions of hypotension. Thresholds for crisis acknowledgment did not significantly differ between PAICs and AOs, suggesting minimal effect from active care responsibility. Many indicated crises at MAP <65 mmHg or after significant deterioration, risking failure-to-rescue events. We suggest that crisis management instruction should address triggers for requesting help.

Aeromedical Transportation of the Critically Ill Cardiac Patient: In-flight Considerations and Management

The aeromedical transportation (AMT) of critically ill cardiac patients can enable access to advanced specialized medical attention, or provide improved care for operational, psychosocial, political, or economic reasons. However, AMT is a complex undertaking necessitating extensive clinical, operational, administrative, and logistical planning to ensure that the patient receives an equivalent level of critical care monitoring and management in the air as on the ground. This paper is the second of a 2-part series. Part 1 focused on the preflight planning and preparation for critically ill cardiac patients during AMT aboard commercial platforms, while this current part aims to provide an overview of in-flight considerations for the same population.

Implication of age-related changes on anesthesia management

Elderly patients have a high risk of perioperative morbidity and mortality. Pluri-morbidities, polypharmacy, and functional dependence may have a great impact on intraoperative management and request specific cautions. In addition to surgical stress, several perioperative noxious stimuli such as fasting, blood loss, postoperative pain, nausea and vomiting, drug adverse reactions, and immobility may trigger a derangement leading to perioperative complications. Older patients have a high risk of major hemodynamic derangement due to aging of the cardiovascular system and associated comorbidities. The hemodynamic monitoring as well as fluid therapy should be the most accurate as possible. Aging is accompanied by decreased renal function, which is related to a reduction in renal blood flow, renal mass, and the number and size of functioning nephrons. Drugs eliminated predominantly by the renal route need dosage adjustments based on residual renal function. Liver mass, hepatic blood flow, and intrinsic metabolic activity are decreased in the elderly, and all drugs metabolized by the liver have a variable half-life, thus requiring dose reduction. Decreased neural plasticity contributes to a high risk for postoperative delirium. Monitoring of anesthesia depth should be mandatory to avoid overdosage of hypnotic drugs. Prevention of postoperative pulmonary complications requires both protective ventilation strategies and adequate recovery of neuromuscular function at the end of surgery. Avoidance of hypothermia cannot be missed. The aim of this review is to describe comprehensive strategies for intraoperative management plans tailored to meet the unique needs of elderly surgical patients, thus improving outcomes in this vulnerable population.

The Influence of Modifiable Risk Factors on Postoperative Outcomes in Patients Receiving Surgery for Resection for Acoustic Neuroma

Acoustic neuromas are the most common tumor of the cerebellopontine angle that are associated with a number of symptoms that negatively impact a patient's quality of life. While the mainstay of treatment for these benign tumors remains microsurgical resection, there is limited research exploring how certain modifiable risk factors (MRFs) may affect the perioperative course. The purpose of this study was to investigate how MRFs including malnutrition, obesity, dyslipidemia, uncontrolled hypertension, and smoking may affect postoperative rates of readmission and nonroutine discharges. We utilized the 2016 and 2017 Healthcare Cost and Utilization Project Nationwide Readmissions Database. MRFs were queried using appropriate International Classification of Diseases, Tenth Revision (ICD-10) coding for categories including malnutrition, obesity, dyslipidemia, smoking, alcohol, and hypertension. The statistical analysis was done using RStudio (Version 1.3.959). Chi-squared tests were done to evaluate differences between categorical variables. The Mann-Whitney U-testing was utilized to evaluate for statistically significant differences in continuous data. The "Epitools" package was used to develop logistic regression models for postoperative complications and post hoc receiver operating characteristic curves were developed. Pertaining to nonroutine discharge, predictive models using malnutrition outperformed all other MRFs as well as those with no MRFs (P < .05). In the case of readmission, models using malnutrition outperformed those of obesity and smoking (P < .05). Again, an increase in predictive power is seen in models using dyslipidemia when compared to obesity, smoking, or uncontrolled hypertension. Lastly, models using no MRFs outperformed those of obesity, smoking, and uncontrolled hypertension (P < .05). This is the first study of its kind to evaluate the role of MRFs in those undergoing surgical resection of their acoustic neuroma. We concluded that certain MRFs may play a role in complicating a patient's perioperative surgical course.

Blood Pressure Goals in Critically Ill Patients

Blood pressure goals in the intensive care unit (ICU) have been extensively investigated in large datasets and have been associated with various harm thresholds at or greater than a mean pressure of 65 mm Hg. While it is difficult to perform interventional randomized trials of blood pressure in the ICU, important evidence does not support defense of a higher pressure, except in retrospective database analyses. Perfusion pressure may be a more important target than mean pressure, even more so in the vulnerable patient population. In the cardiac ICU, blood pressure targets are tailored to specific cardiac pathophysiology and patient characteristics. Generally, the goal is to maintain adequate blood pressure within a certain range to support cardiac function and to ensure end organ perfusion. Individualized targets demand the use of both invasive and noninvasive monitoring modalities and frequent titration of medications and/or mechanical circulatory support where necessary. In this review, we aim to identify appropriate blood pressure targets in the ICU, recognizing special patient populations and outlining the risk factors and predictors of end organ failure.

The Associations of Pulse Pressure and Mean Arterial Pressure on Physical Function in Older Americans

Background: We sought to examine the associations of pulse pressure (PP) and mean arterial pressure (MAP) on physical function in older Americans. Methods: Our analytic sample included 10,478 adults aged ≥65 years from the 2006–2016 Health and Retirement Study. Handgrip strength, gait speed, and standing balance were collected using relatively standard protocols. PP and MAP were calculated from blood pressure measurements. Results: Older Americans with any abnormality in PP had 1.15 (95% confidence interval (CI): 1.05–1.25) greater odds for slowness and 1.14 (CI: 1.05–1.24) greater odds for poorer standing balance. Persons with any abnormality in MAP had 0.90 (CI: 0.82–0.98) decreased odds for weakness and 1.10 (CI: 1.01–1.20) greater odds for poorer standing balance. Those with low PP had 1.19 (CI: 1.03–1.36) greater odds for slow gait speed, while persons with low MAP had 1.50 (CI: 1.09–2.05) greater odds for weakness and 1.45 (CI: 1.03–2.04) greater odds for slowness. Older Americans with high PP had 1.13 (CI: 1.03–1.25) greater odds for slowness and 1.21 (CI: 1.10–1.32) greater odds for poorer balance, whereas those with high MAP had 0.87 (CI: 0.80–0.95) decreased odds for weakness. Conclusions: Cardiovascular dysfunction, as observed by PP and MAP, may help to explain some of our findings.

Intraoperative Beat-to-Beat Pulse Transit Time (PTT) Monitoring via Non-Invasive Piezoelectric/Piezocapacitive Peripheral Sensors Can Predict Changes in Invasively Acquired Blood Pressure in High-Risk Surgical Patients

BACKGROUND

Non-invasive tracking of beat-to-beat pulse transit time (PTT) via piezoelectric/piezocapacitive sensors (PES/PCS) may expand perioperative hemodynamic monitoring. This study evaluated the ability for PTT via PES/PCS to correlate with systolic, diastolic, and mean invasive blood pressure (SBP_IBP, DBP_IBP, and MAP_IBP, respectively) and to detect SBP_IBP fluctuations.

METHODS

PES/PCS and IBP measurements were performed in 20 patients undergoing abdominal, urological, and cardiac surgery. A Pearson's correlation analysis (r) between 1/PTT and IBP was performed. The predictive ability of 1/PTT with changes in SBP_IBP was determined by area under the curve (reported as AUC, sensitivity, specificity).

RESULTS

Significant correlations between 1/PTT and SBP_IBP were found for PES (r = 0.64) and PCS (r = 0.55) (p < 0.01), as well as MAP_IBP/DBP_IBP for PES (r = 0.6/0.55) and PCS (r = 0.5/0.45) (p < 0.05). A 7% decrease in 1/PTT_PES predicted a 30% SBP_IBP decrease (0.82, 0.76, 0.76), while a 5.6% increase predicted a 30% SBP_IBP increase (0.75, 0.7, 0.68). A 6.6% decrease in 1/PTT_PCS detected a 30% SBP_IBP decrease (0.81, 0.72, 0.8), while a 4.8% 1/PTT_PCS increase detected a 30% SBP_IBP increase (0.73, 0.64, 0.68).

CONCLUSIONS

Non-invasive beat-to-beat PTT via PES/PCS demonstrated significant correlations with IBP and detected significant changes in SBP_IBP. Thus, PES/PCS as a novel sensor technology may augment intraoperative hemodynamic monitoring during major surgery.

Effect of neoadjuvant chemotherapy on intraoperative core temperature in patients with breast cancer: a retrospective cohort study

Background

Clinical evidence suggests that chemotherapeutic agents are associated with neuropathy and peripheral autonomic dysfunction. However, the possible effects of neoadjuvant chemotherapy on intraoperative temperature remain poorly characterised.

Methods

We evaluated patients who underwent a mastectomy for breast cancer between April 2016 and July 2020. Propensity scores were used to match patients who received neoadjuvant chemotherapy with those who did not, and intraoperative core temperature patterns were analysed in the matched cohort. The independent associations between vasopressor use and heart rate during general anaesthesia in the matched cohort were also analysed.

Results

Data from 1764 patients were analysed (882 patients in each group). Both groups presented a similar pattern of heat redistribution and subsequent rewarming; however, the neoadjuvant chemotherapy group did not reach the same intraoperative plateau temperature as the group that did not receive prior chemotherapy, with differences of up to 0.4°C (95% confidence interval: 0.11-0.63°C; P=0.005). In a subgroup analysis, neuropathy in patients who received neoadjuvant chemotherapy was associated with increased use of vasopressors and higher heart rate.

Conclusions

In patients with breast cancer, neoadjuvant chemotherapy is associated with lower plateau core temperatures, increased vasopressor use, and higher heart rates during general anaesthesia, which is more severe in the presence of neuropathy.

Hypertensive Blood Pressure and Its Impact on Functional Outcomes among Older Adults Receiving Comprehensive Geriatric Care

BACKGROUND

Comprehensive geriatric care (CGC) is a multiprofessional treatment for older people which considers medical conditions and functional status. The aim of the presented study is to investigate the impact of hypertensive blood pressure (BP) on functional outcomes among older adults receiving CGC.

METHODS

Functional status was documented by the Barthel index (BI), Tinetti test (TBGT), and timed up and go test (TUG) prior to and after CGC. The results were analyzed in relation to hypertensive BP, indicated by mean BP ≥ 130/80 mmHg determined by 24 h blood pressure monitoring (BPM) while hospitalized.

RESULTS

In the presented monocentric, retrospective, observational study, 490 patients were included (mean age (SD): 83.86 ± 6.17 years, 72.2% females). Hypertension in BPM was found in 302 (61.6%) individuals. Hypertensive BP was associated with the female sex (p < 0.001) and current fracture (p = 0.001), and inversely associated with heart failure (p < 0.001), coronary heart disease (p < 0.001), atrial fibrillation (p < 0.001), urinary tract infection (p = 0.022), and hypocalcemia (p = 0.014). After CGC, improvements in BI (p < 0.001), TBGT (p < 0.001), and TUG (p < 0.001) were observed in patients with both normotensive and hypertensive BP profiles. The proportion of patients with outcome improvements did not differ between the two groups (BI: 84.4% vs. 88.3%, p = 0.285; TBGT: 81.1% vs. 77.7%, p = 0.357; TUG: 50.3% vs. 48.4%, p = 0.711).

CONCLUSION

Patients both with and without hypertensive BP profiles benefited from comprehensive geriatric care with comparable outcome improvements. Particularly, normotensive BP was associated with chronic cardiovascular comorbidities, indicating increased awareness of the importance of BP management in patients diagnosed with cardiac diseases.

Predictive Value of Multimodality Intraoperative Neurophysiological Monitoring During Cardiac Surgery

INTRODUCTION

This study aimed to determine the ability of multimodality intraoperative neurophysiologic monitoring, including somatosensory evoked potentials (SSEP) and EEG, to predict perioperative clinical stroke and stroke-related mortality after open-heart surgery in high-risk patients.

METHODS

The records of all consecutive patients who underwent coronary artery bypass grafting, and cardiac valve repair/replacement with high risk for stroke who underwent both SSEP and EEG recording at the University of Pittsburgh Medical Center between 2009 and 2015 were reviewed. Sensitivity and specificity of these modalities to predict in-hospital clinical strokes and stroke-related mortality were calculated.

RESULTS

A total of 531 patients underwent open cardiac procedures monitored using SSEP and EEG. One hundred thirty-one patients (24.67%) experienced significant changes in either modality. Fourteen patients (2.64%) suffered clinical strokes within 24 hours after surgery, and eight patients (1.50%) died during their hospitalization. The incidence of in-hospital clinical stroke and stroke-related mortality among patients who experienced a significant change in monitoring compared with those with no significant change was 11.45% versus 1.75%. The sensitivity and specificity of significant changes in either SSEP or EEG to predict in-hospital major stroke and stroke-related mortality were 0.93 and 0.77, respectively.

CONCLUSIONS

Intraoperative neurophysiologic monitoring with SSEP and EEG has high sensitivity and specificity in predicting perioperative stroke and stroke-related mortality after open cardiac procedures. These results support the benefits of multimodality neuromonitoring during cardiac surgery.

Baseline associations between household air pollution exposure and blood pressure among pregnant women in the Household Air Pollution Intervention Network (HAPIN) multi-country randomized controlled trial

Cooking and heating using solid fuels can result in dangerous levels of exposure to household air pollution (HAP). HAPIN is an ongoing randomized controlled trial assessing the impact of a liquified petroleum gas stove and fuel intervention on HAP exposure and health in Guatemala, India, Peru, and Rwanda among households that rely primarily on solid cooking fuels. Given the potential impacts of HAP exposure on cardiovascular outcomes during pregnancy, we seek to characterize the relationship between personal exposures to HAP and blood pressure among pregnant women at baseline (prior to intervention) in the study. We assessed associations between PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), BC (black carbon), and CO (carbon monoxide) exposures and blood pressure at baseline, prior to intervention, among 3195 pregnant women between 9 and 19 weeks of gestation. We measured 24-hour personal exposure to PM2.5/BC/CO and gestational blood pressure. Multivariable linear regression models were used to evaluate associations between personal exposures to three air pollutants and blood pressure parameters. Trial-wide, we found moderate increases in systolic blood pressure (SBP) and decreases in diastolic blood pressure (DBP) as exposure to PM2.5, BC, and CO increased. None of these associations, however, were significant at the 0.05 level. HAP exposure and blood pressure associations were inconsistent in direction and magnitude within each country. We observed effect modification by body mass index (BMI) in India and Peru. Compared to women with normal weights, obese women in India and Peru (but not in Rwanda or Guatemala) had higher SBP per unit increase in log transformed PM2.5 and BC exposures. We did not find a cross-sectional association between HAP exposure and blood pressure in pregnant women; however, HAP may be associated with higher blood pressure in pregnant women who are obese, but this increase was not consistent across settings.

Anaesthetic considerations in Shrinking Man syndrome: two case reports

BACKGROUND

Shrinking Man syndrome (SMS) is a rare but often serious complication of dialysis-dependent end-stage renal disease, characterized by significant loss of height, bone pain, bone deformity, and skin itching. Patients with SMS always have abnormal facial changes and cardiovascular system damage (manifested by hypertension, hypotension, cardiovascular calcification, and valvular heart disease), which pose a great challenge to anaesthesiologists. The purpose of this report is to describe our anaesthetic experience regarding two patients with SMS combined with alterations of the airway and cardiovascular system.

CASE PRESENTATION

We describe two cases of SMS treated at West China Hospital, a tertiary care centre in Chengdu, China. All cases met the diagnostic criteria, which comprised 1) dialysis-dependent end-stage renal disease, 2) loss of height, and 3) bone pain and bone deformity. One patient had an anticipated difficult airway and moderate-to-severe mitral stenosis. The other patient presented with significant hypotension. Anaesthetic considerations included awake fibreoptic bronchoscopy-assisted tracheal intubation, real-time transoesophageal echocardiogram monitoring and individualized blood pressure management strategies.

CONCLUSION

This case series highlights the importance of adequate preoperative assessment and preparation, as well as individualized anaesthetic management, in patients with SMS.

Perioperative systemic blood pressure parameters and clinical outcomes following 27g vitrectomy for diabetic tractional detachment repair

Background

Extremes in perioperative blood pressures are known risk factors for adverse outcomes after surgical interventions. There is scarce literature studying these parameters as predictors of outcomes after ocular surgery.

Methods

This was a retrospective single-centre interventional cohort analysis to evaluate the relationship between perioperative (preoperative and intraoperative) blood pressure value and variability and postoperative visual and anatomic outcomes. Included were patients who underwent primary 27-gauge (27g) vitrectomy for repair of diabetic tractional retinal detachment (DM-TRD) with at least 6 months of follow-up. Univariate analyses were conducted via independent two-sided t-tests and Pearson’s χ2tests. Multivariate analyses were conducted via generalised estimating equations.

Results

71 eyes of 57 patients were included in the study. Higher preprocedure mean arterial pressure (MAP) was associated with fewer Snellen lines of improvement at postoperative month 6 (POM6) (p<0.01). Higher mean intraoperative systolic blood pressure (SBP), diastolic blood pressure and MAP were associated with visual acuity 20/200 or worse at POM6 (p<0.05). Patients with sustained intraoperative hypertension had 1.77 times the risk of visual acuity 20/200 or worse at POM6 compared with those without sustained intraoperative hypertension (p=0.006). Higher SBP variability was associated with worse visual outcomes at POM6 (p<0.05). Blood pressure was not associated with macular detachment at POM6 (p>0.10).

Conclusions

Higher average perioperative blood pressure and blood pressure variability are associated with worse visual outcomes in patients undergoing 27g vitrectomy for DM-TRD repair. Patients with sustained intraoperative hypertension were approximately twice as likely to have visual acuity 20/200 or worse at POM6 compared to those without sustained intraoperative hypertension.

Hemispheric Asymmetry on the Electroencephalogram during General Anesthesia Responsive to Blood Pressure Manipulations

The electroencephalogram (EEG) has been extensively used to detect ischemia and the need for shunting during carotid endarterectomy. Limited literature exists using EEG data to detect ischemia in other surgeries. This case report depicts a 65-year-old man, with extensive vascular history including complete left carotid occlusion and severe right carotid stenosis, who presented for left first rib resection and left subclavian vein balloon angioplasty. Following induction of general anesthesia, frontal EEG (SedLine; Masimo Corporation, Irvine, CA, USA) demonstrated hemispheric asymmetry, which nearly resolved with vasoactive support. At three distinct periods, discordance reoccurred necessitating a higher mean arterial pressure threshold. This case demonstrates EEG patterns concerning for focal spectrographic ischemia and highlights the potential use of EEG signals to capture hypoperfusion and direct vasoactive therapy.

Preoperative Evaluation and Cardiac Risk Assessment in Vascular Surgery

We summarize epidemiologic trends, outcomes, and preoperative guidelines for vascular surgery patients from 2010 to 2022. Vascular surgery continues to evolve in technology and engineering to treat a surgical population that suffers from a high prevalence of comorbidities. Preoperative optimization seeks to characterize the burden of disease and to achieve medical control in the timeline available before surgery. Risk assessment, evaluation, optimization, and prediction of major adverse cardiac events is an evolving science where the Vascular Surgery Quality Initiative has made an impact. Ongoing investigation may demonstrate value for preoperative echocardiography, functional capacity, frailty, and mobility assessments.

Preoperative clinical diagnostic accuracy of heart failure among patients undergoing major noncardiac surgery: a single-centre prospective observational analysis

Background

Reliable diagnosis of heart failure during preoperative evaluation is important for perioperative management and long-term care. We aimed to quantify preoperative heart failure diagnostic accuracy and explore characteristics of patients with heart failure misdiagnoses.

Methods

We performed an observational cohort study of adults undergoing major noncardiac surgery at an academic hospital between 2015 and 2019. A preoperative clinical diagnosis of heart failure was defined using keywords from the history and clinical examination or administrative documentation. Across stratified subsamples of cases with and without clinically diagnosed heart failure, health records were intensively reviewed by an expert panel to develop an adjudicated heart failure reference standard using diagnostic criteria congruent with consensus guidelines. We calculated agreement among experts, and analysed performance of clinically diagnosed heart failure compared with the adjudicated reference standard.

Results

Across 40 555 major noncardiac procedures, a stratified subsample of 511 patients was reviewed by the expert panel. The prevalence of heart failure was 9.1% based on clinically diagnosed compared with 13.3% (95% confidence interval [CI], 10.3-16.2%) estimated by the expert panel. Overall agreement and inter-rater reliability (kappa) among heart failure experts were 95% and 0.79, respectively. Based upon expert adjudication, heart failure was clinically diagnosed with an accuracy of 92.8% (90.6-95.1%), sensitivity 57.4% (53.1-61.7%), specificity 98.3% (97.1-99.4%), positive predictive value 83.5% (80.3-86.8%), and negative predictive value 93.8% (91.7-95.9%).

Conclusions

Limitations exist to the preoperative clinical diagnosis of heart failure, with nearly half of cases undiagnosed preoperatively. Considering the risks of undiagnosed heart failure, efforts to improve preoperative heart failure diagnoses are warranted.

Association of intraoperative dexmedetomidine use with postoperative hypotension in unilateral hip and knee arthroplasties: a historical cohort study

PURPOSE

Dexmedetomidine is frequently used as a sedative agent for orthopedic surgery patients undergoing total hip or knee arthroplasty. Although the benefits of dexmedetomidine are well described in the literature, there is also potential for harm, especially regarding the hemodynamic effects of dexmedetomidine in the postoperative setting.

METHODS

This historical cohort study included all primary unilateral total hip or knee arthroplasties conducted from April 2017 to February 2020 in a single, university-affiliated, tertiary care centre (Jewish General Hospital, Montreal, QC, Canada). We used multivariable logistic regression to analyze the predictors for postoperative hypotension, defined as a systolic blood pressure < 90 mm Hg or any systolic blood pressure while on a vasopressor infusion in the postanesthesia care unit. Models were validated using calibration and discrimination with bootstrapping technique.

RESULTS

One thousand five hundred and eighty-eight patients were included in this study. Postoperative hypotension occurred in 413 (26%) patients. Statistically significant predictors for postoperative hypotension included female sex (adjusted odds ratio [aOR], 3.24; 95% confidence interval [CI], 2.29 to 4.58), a history of transient ischemic attack or cerebrovascular accident (aOR, 1.97; 95% CI, 1.04 to 3.72), and intraoperative dexmedetomidine use (aOR, 2.61; 95% CI, 1.99 to 3.42). Moreover, the risk of postoperative hypotension was approximately two times higher than baseline, with a total intraoperative dexmedetomidine dose above 50 μg (relative risk, 1.99; 95% CI, 1.63 to 2.44; P < 0.001). A higher preoperative systolic blood pressure (aOR, 0.98; 95% CI, 0.97 to 0.99) was a protective factor for postoperative hypotension.

CONCLUSION

In this historical cohort study, dexmedetomidine was a strong risk factor for postoperative hypotension in total hip or knee arthroplasty patients. Dexmedetomidine, and particularly at high cumulative doses above 50 μg, should be administered judiciously in high-risk surgical patients to minimize the risk of postoperative hypotension.

High versus low blood pressure targets for cardiac surgery while on cardiopulmonary bypass

BACKGROUND

Cardiac surgery is performed worldwide. Most types of cardiac surgery are performed using cardiopulmonary bypass (CPB). Cardiac surgery performed with CPB is associated with morbidities. CPB needs an extracorporeal circulation that replaces the heart and lungs, and performs circulation, ventilation, and oxygenation of the blood. The lower limit of mean blood pressure to maintain blood flow to vital organs increases in people with chronic hypertension. Because people undergoing cardiac surgery commonly have chronic hypertension, we hypothesised that maintaining a relatively high blood pressure improves desirable outcomes among the people undergoing cardiac surgery with CPB.

OBJECTIVES

To evaluate the benefits and harms of higher versus lower blood pressure targets during cardiac surgery with CPB.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search of databases was November 2021 and trials registries in January 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing a higher blood pressure target (mean arterial pressure 65 mmHg or greater) with a lower blood pressure target (mean arterial pressure less than 65 mmHg) in adults undergoing cardiac surgery with CPB.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were 1. acute kidney injury, 2. cognitive deterioration, and 3. all-cause mortality. Secondary outcomes were 4. quality of life, 5. acute ischaemic stroke, 6. haemorrhagic stroke, 7. length of hospital stay, 8. renal replacement therapy, 9. delirium, 10. perioperative transfusion of blood products, and 11. perioperative myocardial infarction. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included three RCTs with 737 people compared a higher blood pressure target with a lower blood pressure target during cardiac surgery with CPB. A high blood pressure target may result in little to no difference in acute kidney injury (risk ratio (RR) 1.30, 95% confidence interval (CI) 0.81 to 2.08; I² = 72%; 2 studies, 487 participants; low-certainty evidence), cognitive deterioration (RR 0.82, 95% CI 0.45 to 1.50; I² = 0%; 2 studies, 389 participants; low-certainty evidence), and all-cause mortality (RR 1.33, 95% CI 0.30 to 5.90; I² = 49%; 3 studies, 737 participants; low-certainty evidence). No study reported haemorrhagic stroke. Although a high blood pressure target may increase the length of hospital stay slightly, we found no differences between a higher and a lower blood pressure target for the other secondary outcomes. We also identified one ongoing RCT which is comparing a higher versus a lower blood pressure target among the people who undergo cardiac surgery with CPB.

AUTHORS' CONCLUSIONS

A high blood pressure target may result in little to no difference in patient outcomes including acute kidney injury and mortality. Given the wide CIs, further studies are needed to confirm the efficacy of a higher blood pressure target among those who undergo cardiac surgery with CPB.