Arterial Blood Pressure Management Research Articles

Individualized autoregulation-guided arterial blood pressure management in neurocritical care.

Cerebral autoregulation (CA) is the physiological process by which cerebral blood flow is maintained during fluctuations in arterial blood pressure (ABP). There are various validated methods to measure CA, either invasively, with intracranial pressure or brain tissue oxygenation monitors, or noninvasively, with transcranial Doppler ultrasound or near-infrared spectroscopy. Utilizing these monitors, researchers have been able to discern CA patterns in several pathological states, such as but not limited to acute ischemic stroke, spontaneous intracranial hemorrhage, aneurysmal subarachnoid hemorrhage, sepsis, and post-cardiac arrest, and they have found CA to be altered in these patients. CA disturbances predispose patients suffering from these ailments to worse outcomes. Much focus has been placed on CA monitoring in these populations, with an emphasis on arterial blood pressure optimization. Many guidelines recommend universal static ABP targets; however, in patients with altered CA, these targets may make them susceptible to hypoperfusion and further neurological injury. Based on this observation, there has been much investigation on individualized ABP goals and their effect on clinical outcomes. The scope of this review includes (1) a summary of the physiology of CA in healthy adults; (2) a review of the evidence on CA monitoring in healthy individuals; (3) a summary of CA changes and its effect on outcomes in various diseased states including acute ischemic stroke, spontaneous intracranial hemorrhage, aneurysmal subarachnoid hemorrhage, sepsis and meningitis, post-cardiac arrest, hypoxic-ischemic encephalopathy, surgery, and moyamoya disease; and (4) a review of the current evidence on individualized ABP changes in various patient populations.

The optimal management of arterial blood pressure in acute stroke: A never-ending conundrum

The optimal management of arterial blood pressure in acute stroke: A never-ending conundrum

Cerebral autoregulation metrics correlate with some major morbidity and mortality outcomes after cardiac surgery

Background: Personalized arterial blood pressure management based on cerebral autoregulation has shown clinical relevance in cardiac surgery. Here we explore the associations between lower limit of cerebral autoregulation (LLA) metrics and postoperative outcomes in a heterogenous and high-acuity population of patients undergoing high-risk cardiovascular surgery. Methods: Autoregulation parameters were determined retrospectively in 686 patients undergoing cardiac surgery at UAB Hospital. Cerebral oximetry index (COx) and hemoglobin volume reactivity index (HVx) determine a patient’s unique LLA by examining the correlation between mean arterial pressure (MAP) and near-infrared spectroscopy signals. Logistic regression analyses explored associations of area under the time-pressure curve and duration below LLA with stroke, acute kidney injury, operative mortality, low cardiac output syndrome, and mechanical ventilation lasting more than 48 hours. Any incidence of these outcomes was considered as the primary outcome of interest: major morbidity or operative mortality (MMOM). Results: We explored the association of Area under the time-pressure curve for pressures less than patient-specific Lower Limits of Autoregulation (AUCABP<LLA: and MMOM. Results are reported with odds ratio (OR) and 95% confidence intervals (CI). AUCABP<LLA was not significantly associated with MMOM incidence (HVx: Odds Ratio 1.000, 95% CI 0.970-1.030, p=0.979; COx: OR 1.006, 95% CI 0.990-1.023, p=0.456). However, for components of MMOM, specifically operative mortality (HVx: OR 1.063, 95% CI 1.013-1.115, p=0.013; COx: OR 1.027, 95% CI 1.001-1.052, p=0.038) and low cardiac output syndrome (HVx: OR 1.036, 95% CI 1.004-1.068, p=0.025), there were statistically significant relationships with AUCABP<LLA when controlling for logistic Euroscore and preoperative hemoglobin levels. Conclusions: Area under the time-pressure curve for pressures less than patient-specific LLA was not significantly associated with MMOM incidence. However, we found significant associations between components of MMOM, specifically operative mortality and low cardiac output syndrome, with an AUCABP<LLA and time under LLA. These results suggest that LLA metrics might have utility in predicting specific postoperative outcomes, but their role in predicting overall MMOM may be limited in heterogenous and high-acuity patient populations. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Near-Infrared Spectroscopy-Guided, Individualized Arterial Blood Pressure Management for Carotid Endarterectomy under General Anesthesia: A Randomized, Controlled Trial.

Background: Differences in blood pressure can influence the risk of brain ischemia, perioperative complications, and postoperative neurocognitive function in patients undergoing carotid endarterectomy (CEA). Methods: In this single-center trial, patients scheduled for CEA under general anesthesia were randomized into an intervention group receiving near-infrared spectroscopy (NIRS)-guided blood pressure management during carotid cross-clamping and a control group receiving standard care. The primary endpoint was postoperative neurocognitive function assessed before surgery, on postoperative days 1 and 7, and eight weeks after surgery. Perioperative complications and cerebral autoregulatory capacity were secondary endpoints. Results: Systolic blood pressure (p < 0.001) and norepinephrine doses (89 (54-122) vs. 147 (116-242) µg; p < 0.001) during carotid cross-clamping were lower in the intervention group. No group differences in postoperative neurocognitive function were observed. The rate of perioperative complications was lower in the intervention group than in the control group (3.3 vs. 26.7%, p = 0.03). The breath-holding index did not differ between groups. Conclusions: Postoperative neurocognitive function was comparable between CEA patients undergoing general anesthesia in whom arterial blood pressure during carotid cross-clamping was guided using NIRS and subjects receiving standard care. NIRS-guided, individualized arterial blood pressure management resulted in less vasopressor exposition and a lower rate of perioperative complications.

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

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

Perspective on Cerebral Autoregulation Monitoring in Neonatal Cardiac Surgery Requiring Cardiopulmonary Bypass.

The autoregulation of cerebral blood flow protects against brain injury from transient fluctuations in arterial blood pressure. Impaired autoregulation may contribute to hypoperfusion injury in neonates and infants. Monitoring cerebral autoregulation in neonatal cardiac surgery as a guide for arterial blood pressure management may reduce neurodevelopmental morbidity. Cerebral autoregulation monitoring has been validated in animal models and in an adult trial autoregulation monitoring during bypass improved postoperative delirium scores. The nuances of pediatric cardiac disease and congenital heart surgery make simply applying adult trial findings to this unique population inappropriate. Therefore, dedicated pediatric clinical trials of cerebral autoregulation monitoring are indicated.

Impact of Arterial Blood Pressure Management in Acute Ischemic Stroke on Short Term Outcome and Prognosis

Background: Blood pressure (BP) is elevated in 75% or more of patients with acute stroke and is associated with poor outcomes. Whether to modulate BP in acute stroke has long been debated. With the loss of normal cerebral autoregulation, theoretical concerns are twofold: high BP can lead to cerebral edema, hematoma expansion or hemorrhagic transformation; and low BP can lead to increased cerebral infarction or perihematomal ischemia. Objective: To determine the impact of arterial blood pressure management in acute ischemic stroke on short term outcome and prognosis. Patients and methods: This study included 200 patients diagnosed with ischemic stroke and arrived to Emergency Hospital, Mansoura University over a year from June 2019 to June 2020. The cases were classified into 4 groups according to the systolic BP (SBP) of the cases; control group (SBP < 140 mmHg), group 2 (SBP 140-160 mmHg) group 3 (SBP 160-180 mmHg) and group 4 (SBP 180-200 mmHg). Results: The stroke score (follow up) according to blood pressure groups showed no statistically significant difference between the groups. Regarding the initial CT findings of the cases according to blood pressure groups, fourth group has more changes in CT brain, with a highly statistical significant difference observed between the groups. Conclusion: Elevated blood pressure in patients with stroke were associated with worse outcomes including ICU admission, mortality and duration of hospital admission. CT findings supported these findings as the percent of cases presented with initial infarction and cases who showed hemorrhagic transformation increased with elevation of BP.

Blood pressure and glaucoma: At the crossroads between cardiology and ophthalmology.

Glaucoma is an optic nerve neuropathy of undetermined cause. Although many mechanisms are thought to be involved in the development and progression of the disease, only an increased intraocular pressure has been established as a clinically significant modifiable risk factor. Nevertheless, up to 40% of patients develop glaucoma without evidence of increased intraocular pressure. Ample evidence suggests that alterations in the control of arterial blood might negatively affect optic nerve function. However, evidence-based guidelines on the management of arterial blood pressure in glaucoma patients are lacking. Regrettably, intraocular pressure is generally not included as a secondary end-point in clinical trials on arterial hypertension. Considering the relative simplicity of intraocular pressure measurements and large number of patients included in hypertension studies, the benefits of including intraocular pressure as a secondary end-point could be of a great value for improving care for glaucoma patients. Therefore, closer collaboration between cardiologists and ophthalmologists is needed.

Perioperative Quality Initiative consensus statement on intraoperative blood pressure, risk and outcomes for elective surgery

BackgroundIntraoperative mortality is now rare, but death within 30 days of surgery remains surprisingly common. Perioperative myocardial infarction is associated with a remarkably high mortality. There are strong associations between hypotension and myocardial injury, myocardial infarction, renal injury, and death. Perioperative arterial blood pressure management was thus the basis of a Perioperative Quality Initiative consensus-building conference held in London in July 2017. MethodsThe meeting featured a modified Delphi process in which groups addressed various aspects of perioperative arterial pressure. ResultsThree consensus statements on intraoperative blood pressure were established. 1) Intraoperative mean arterial pressures below 60–70 mm Hg are associated with myocardial injury, acute kidney injury, and death. Injury is a function of hypotension severity and duration. 2) For adult non-cardiac surgical patients, there is insufficient evidence to recommend a general upper limit of arterial pressure at which therapy should be initiated, although pressures above 160 mm Hg have been associated with myocardial injury and infarction. 3) During cardiac surgery, intraoperative systolic arterial pressure above 140 mm Hg is associated with increased 30 day mortality. Injury is a function of arterial pressure severity and duration. ConclusionsThere is increasing evidence that even brief durations of systolic arterial pressure <100 mm Hg and mean arterial pressure <60–70 mm Hg are harmful during non-cardiac surgery.

Perioperative Quality Initiative consensus statement on the physiology of arterial blood pressure control in perioperative medicine

BackgroundPerioperative arterial blood pressure management is a physiologically complex challenge influenced by multiple factors. MethodsA multidisciplinary, international working subgroup of the Third Perioperative Quality Initiative (POQI) consensus meeting reviewed the (patho)physiology and measurement of arterial pressure as applied to perioperative medicine. We addressed predefined questions by undertaking a modified Delphi analysis, in which primary clinical research and review articles were identified using MEDLINE. Strength of recommendations, where applicable, were graded by National Institute for Health and Care Excellence (NICE) guidelines. ResultsMultiple physiological factors contribute to the perioperative physiological importance of arterial pressure: (i) arterial pressure is the input pressure to organ blood flow, but is not the sole determinant of perfusion pressure; (ii) blood flow is often independent of changes in perfusion pressure because of autoregulatory changes in vascular resistance; (iii) microvascular dysfunction uncouples microvascular blood flow from arterial pressure (haemodynamic incoherence). From a practical clinical perspective, we identified that: (i) ambulatory measurement is the optimal method to establish baseline arterial pressure; (ii) automated and invasive arterial pressure measurements have inherent physiological and technical limitations; (iii) individualised arterial pressure targets may change over time, especially in the perioperative period. There remains a need for research in non-invasive, continuous arterial pressure measurements, macro- and micro-circulatory control, regional perfusion pressure measurement, and the development of sensitive, specific, and continuous measures of cellular function to evaluate blood pressure management in a physiologically coherent manner. ConclusionThe multivariable, complex physiology contributing to dynamic changes in perioperative arterial pressure may be underappreciated clinically. The frequently unrecognised dissociation between arterial pressure, organ blood flow, and microvascular and cellular function requires further research to develop a more refined, contextualised clinical approach to this routine perioperative measurement.

Mean Arterial Blood Pressure Management of Acute Traumatic Spinal Cord Injured Patients during the Pre-Hospital and Early Admission Period.

The optimization and maintenance of mean arterial blood pressure (MAP) and the general avoidance of systemic hypotension for the first 5-7 days following acute traumatic spinal cord injury (tSCI) is considered to be important for minimizing secondary spinal cord ischemic damage. The characterization of hemodynamic parameters in the immediate post-injury stage prior to admission to a specialized spine unit has not been previously reported. Here we describe the blood pressure management of 40 acute tSCI patients in the early post-injury phases of care prior to their arrival in a specialized spinal injury high dependency unit (HDU), intensive care unit (ICU), or operating room (OR). This study found that a significant proportion of these patients experience periods of relative hypotension prior to their admission to a specialized spinal unit. In particular, the mean calculated MAP was 78.8 mm Hg, with 52% of MAP measurements <80 mm Hg at primary receiving hospitals. Despite having a mean calculated MAP of 83.3 mm Hg in the emergency room of the tertiary hospital, 40% of the MAP measurements were <80 mm Hg. Although stringent monitoring and management of MAP may be facilitated and adhered to in a spinal HDU, ICU, or OR, it is important to recognize that acute traumatic SCI patients may experience many periods of relative hypotension prior to their arrival in such specialized units. This study highlights the need for education and awareness to optimize the hemodynamic management of acute SCI patients during the immediate post-injury period.

Contrast-Enhanced Ultrasound Imaging in Detection of Changes in Cerebral Perfusion

Contrast-enhanced ultrasonography (CEU) is a non-invasive imaging technique that provides real-time, bedside information on changes in global and segmental organ perfusion. Currently, there is a lack of data concerning changes in the distribution of segmental brain perfusion in acute ischemic stroke treated by decompressive craniectomy. The aim of our case series was to assess the role of CEU after decompressive craniectomy in patients with acute ischemic stroke. CEU was performed in 12 patients at baseline and after any one of the following interventions was performed as dictated by the patient's clinical condition: vasoactive drug administration (in order to achieve cerebral perfusion pressure ≥70 mm Hg and mean arterial pressure <100 mm Hg for management of arterial blood pressure) and mild hyperventilation (carbon dioxide arterial pressure = 30–35 mm Hg). CEU was able to detect a significant variation in cerebral contrast distribution in both normal and pathologic hemispheres after induced hyperventilation (difference in time to peak [dTTP] = −38.4%), vasodilation (dTTP = −6.6%) and vasoconstriction (dTTP = +31.2%) (p < 0.05). CEU can be useful in assessing real-time cerebral perfusion changes in neurocritical care patients.

Effect of transcutaneous electrical nerve stimulation on peripheral to central blood pressure ratio in healthy subjects.

To investigate the effect of transcutaneous electrical nerve stimulation (TENS) on the arterial stiffness in healthy young adult and middle-aged men using the augmentation index (AI-x) and hemodynamic measures. Twenty-four men (12 aged 27·25±5·53years and 12 aged 54·83±5·10years) were randomly allocated to two subgroups: TENS or placebo in ganglion region for 45min. The AI-x and hemodynamic measures [late systolic blood pressure (SBP), central blood pressure (CBP), difference between P1 and P2 (ΔP) and tension time index (TTI)] were determined before and after protocols. TENS resulted in reduction of SBP in younger adults (TENSpre: 111±2; post: 105±2·2mm Hg; PLACEBOpre: 113±1·8; post: 114±2·5mm Hg; GEE, P<0·01), whereas no difference was found in middle-aged group. TENS also resulted in reduction of AI-x younger adults group (TENSpre: 56±2·8; post: 53±2%; PLACEBOpre: 55±3; post: 58±2·5%; GEE, P<0·01). ΔP and TTI were significantly decreased after the application of TENS in both groups, but significantly greater reductions in TTI and the SBP/CBP ratio were found in the group of younger adults. The acute application of ganglion TENS attenuated arterial stiffness in younger adults as well as hemodynamic measures in the middle-aged group. This method could emerge as effective therapy for the management of arterial blood pressure.

Optimal perioperative management of arterial blood pressure.

Perioperative blood pressure management is a key factor of patient care for anesthetists, as perioperative hemodynamic instability is associated with cardiovascular complications. Hypertension is an independent predictive factor of cardiac adverse events in noncardiac surgery. Intraoperative hypotension is one of the most encountered factors associated with death related to anesthesia. In the preoperative setting, the majority of antihypertensive medications should be continued until surgery. Only renin-angiotensin system antagonists may be stopped. Hypertension, especially in the case of mild to moderate hypertension, is not a cause for delaying surgery. During the intraoperative period, anesthesia leads to hypotension. Hypotension episodes should be promptly treated by intravenous vasopressors, and according to their etiology. In the postoperative setting, hypertension predominates. Continuation of antihypertensive medications and postoperative care may be insufficient. In these cases, intravenous antihypertensive treatments are used to control blood pressure elevation.

Continuous time-domain monitoring of cerebral autoregulation in neurocritical care

Integration of various brain signals can be used to determine cerebral autoregulation in neurocritical care patients to guide clinical management and to predict outcome. In this review, we will discuss current methodology of multimodal brain monitoring focusing on secondary ‘reactivity indices’ derived from various brain signals which are based on a ‘moving correlation coefficient’. This algorithm was developed in order to analyze in a time dependent manner the degree of correlation between two factors within a time series where the number of paired observations is large. Of the various primary neuromonitoring sources which can be used to calculate reactivity indices, we will focus in this review on indices based on transcranial Doppler (TCD), intracranial pressure (ICP), brain tissue oxygenation (PbtO2) and near infrared spectroscopy (NIRS). Furthermore, we will demonstrate how reactivity indices can show transient changes of cerebral autoregulation and can be used to optimize management of arterial blood pressure (ABP) and cerebral perfusion pressure (CPP).

Analysis of a sample of type 2 diabetic patients with obesity or overweight and at cardiovascular risk: a cross sectional study in Spain

BackgroundThe multifactorial control of diabetes relies on interventions that provide patients with the best knowledge and resources available. The objective of this research was to analyze the clinical characteristics of a sample of people with type 2 diabetes at high cardiovascular risk, and establish possible links between disease control, family history and lifestyle, to improve the quality of interventions. Family history, lifestyle habits, blood pressure, anthropometric data and laboratory tests were analyzed in this descriptive and comparative cross-sectional study.ResultsAll patients had a pathological body mass index (BMI), and in those patients with a family history of diabetes, the disease was more serious and onset was earlier. Overall, 70.9% were taking drugs for arterial blood pressure management, with mean values within recommended limits; 87.1% were taking antihyperlipidemic drugs and had mean values for blood lipids within reference range; 93.5% were receiving oral antidiabetic drugs and/or insulin and had blood glucose and glycosylated hemoglobin (HbA1c) values higher than recommended limit; and 87% were taking antiplatelet drugs and had fibrinogen and ultrasensitive C-reactive protein higher than the normal range. High HbA1c values were found in a high proportion of our sample who were not following a tailored diet (84.2%), and better BMIs were associated with moderate physical activity. Coexistence of somatic disorders (97.4% of the sample with musculoskeletal diseases) could lead to the lack of physical activity.ConclusionsThis sample of patients with type 2 diabetes and at high cardiovascular risk, had acceptable metabolic control, facilitated by drug therapy. Family history of diabetes was associated with earlier disease onset and worse disease progression. Patients who were not following a tailored diet had worse HbA1c values compared with those who were. Individuals who practiced moderate physical activity in line with international recommendations for weight maintenance had the best BMI values, but the high prevalence of comorbidities could adversely affect exercise habits. Appropriate use of medication, dietary advice, and tailored physiotherapy physical activity suitable for people with comorbidities should be included in multifactorial treatment strategies for these patients, particularly in the presence of a family history of diabetes.

Arterial blood pressure management during carotid endarterectomy and early cognitive dysfunction.

A common practice during cross-clamp of carotid endarterectomy (CEA) is to manage mean arterial pressure (MAP) above baseline to optimize the collateral cerebral blood flow and reduce the risk of ischemic stroke. To determine whether MAP management ≥20% above baseline during cross-clamp is associated with lower risk of early cognitive dysfunction, a subtler form of neurological injury than stroke. One hundred eighty-three patients undergoing CEA were enrolled in this ad hoc study. All patients had radial arterial catheters placed before the induction of general anesthesia. MAP was managed at the discretion of the anesthesiologist. All patients were evaluated with a battery of neuropsychometric tests preoperatively and 24 hours postoperatively. Overall, 28.4% of CEA patients exhibited early cognitive dysfunction (eCD). Significantly fewer patients with MAP ≥20% above baseline during cross-clamp exhibited eCD than those managed <20% above (11.6% vs 38.6%, P < .001). In a multivariate logistic regression model, MAP ≥20% above baseline during the cross-clamp period was associated with significantly lower risk of eCD (odds ratio [OR], 0.18 [0.07-0.40], P < .001), whereas diabetes mellitus (OR, 2.73 [1.14-6.61], P = .03) and each additional year of education (OR, 1.19 [1.06-1.34], P = .003) were associated with significantly higher risk of eCD. The observations of this study suggest that MAP management ≥20% above baseline during cross-clamp of the carotid artery may be associated with lower risk of eCD after CEA. More prospective work is necessary to determine whether MAP ≥20% above baseline during cross-clamp can improve the safety of this commonly performed procedure.

The Hemodynamic Management of 5177 Neurosurgical and Orthopedic Patients Who Underwent Surgery in the Sitting or “Beach Chair” Position Without Incidence of Adverse Neurologic Events

A small number of highly publicized case reports describe ischemic brain or spinal cord injury after surgery in the sitting ("beach chair") position. The incidence of such catastrophic outcomes remains unknown, as does the relationship between arterial blood pressure management and injury, because few hemodynamic details were included with those 4 cases. To add quantitative data to the discussion of anesthesia in the sitting position, we examined the detailed hemodynamics of a large number of patients managed at our institution who sustained no similar catastrophic outcomes. A comprehensive, retrospective, interrogation was performed of the electronic hemodynamic record for all 5177 patients who underwent either orthopedic shoulder surgery or neurological surgery in the sitting position at Mayo Clinic Rochester between January 1, 2002 and December 31, 2009. No immediate postoperative catastrophic outcomes occurred in 5177 sitting patients undergoing surgery and general anesthesia in the sitting position. For orthopedic shoulder surgery patients, intraoperative systolic blood pressures obtained from an arterial line referenced to heart level decreased 14.4% ± 12.7% (mean ± SD), and those obtained from a noninvasive blood pressure (NIBP) cuff referenced to heart level decreased 19.3% ± 12.6%. For neurosurgical patients, the average reductions in intraoperative mean arterial blood pressures from baseline were 17.6% ± 11.5% and 19.7% ± 10.7% for patients with heart- and head-level transducer placement, respectively. The absolute intraoperative mean arterial blood pressures (mean ± SD) for orthopedic patients measured by NIBP referenced to heart level were 75 ± 8 mm Hg; for orthopedic patients measured from an arterial line referenced to heart level were 74 ± 7 mm Hg; for neurosurgical patients measured with an arterial line referenced to heart level were 78 ± 7 mm Hg; and for neurosurgical patients measured with an arterial line referenced to head level were 75 ± 7 mm Hg. Over the entire duration of surgery, 52% (95% confidence interval [CI], 49%-56%) of neurosurgical patients, 51% (95% CI, 47%-55%) of orthopedic patients monitored with an A-line, and 48% (95% CI, 46%-50%) of orthopedic patients monitored with NIBP experienced ≥1 episodes of systolic blood pressure reduction >40% below baseline. This study provides a descriptive summary of intraoperative blood pressure changes, measured either invasively or noninvasively, and referenced to either head or heart level, but never lower than heart level, in patients under general anesthesia in the sitting position who sustained no catastrophic outcomes.

The Effect of Antihypertensive Class on Intraoperative Pressor Requirements During Carotid Endarterectomy

Certain classes of antihypertensive drugs have been associated with intraoperative hypotension, and frequently, patients are receiving multiple classes of antihypertensive medications. We sought to determine whether one class of antihypertensive medication either alone, or in combination with other classes of antihypertensive medications, increased the probability of intraoperative hypotension, determined by the amount of vasopressor required during carotid endarterectomy (CEA) performed under general anesthesia with specific arterial blood pressure management. This is a post hoc analysis of 252 patients scheduled for elective CEA under general anesthesia, all of whom participated in a prospective evaluation of cognitive dysfunction. Patients were characterized by class and number of preoperative antihypertensive medications taken. A predetermined anesthetic regimen was administered to all patients, with a phenylephrine infusion titrated to maintain mean arterial blood pressure at baseline before clamping the carotid artery, and approximately 20% above baseline during clamping. Computerized anesthesia records were used to record hemodynamics and to quantify medication administered intraoperatively. Patients taking diuretics as part of their antihypertensive regimen required significantly more (1.6 times) total intraoperative phenylephrine than those not taking diuretics, independently of the number of other antihypertensive medications. This difference in the phenylephrine requirement occurs only during the preclamp period, i.e., from induction to application of carotid artery clamping for the maintenance of preoperative blood pressure. However, in contrast to this result, there is no difference in pressor requirement comparing classes of antihypertensive medications to increase the mean arterial blood pressure 20% above baseline during the period when the carotid artery is clamped. Diuretics are associated with increased vasopressor requirements in patients having a CEA under general anesthesia in the preclamp period, which is likely true for any patient having a general anesthetic.

Role of Transcranial Doppler in Optimizing Treatment of Cerebral Vasospasm in Subarachnoid Hemorrhage

This study was undertaken to evaluate the role of transcranial Doppler ultrasonography in arterial blood pressure management during hypervolemia/hypertension/ hemodilution therapy in patients with vasospasm from subarachnoid hemorrhage and correlate this data with neurologic outcome. The study included 18 adult patients, Hunt and Hess grades III-IV. Complete neurologic assessment was performed. Transcranial Doppler indices were calculated by standard formulas. On the basis of our results, resistance area product can be used to estimate the optimal arterial blood pressure in hypervolemia/hypertension/hemodilution therapy. An increase in the cerebral blood flow index was associated with better performance on neurologic examination. Estimated cerebral perfusion pressure from transcranial Doppler data analysis showed poor correlation with cerebral perfusion pressure derived from direct measurement of intracranial pressure in patients with cerebral vasospasm (rho = 0.15; 95% CI, 0.11-0.39; P = .2590).