Drop In Arterial Pressure Research Articles

Microscopic Varicocelectomy under Local Anesthesia as the Treatment of Varicocele.

Varicocele, characterized by the dilation of veins within the spermatic cord, is a prevalent disease in males, accounting for 35%-40% of infertility cases among men of reproductive age. This condition may disrupt normal neuroregulation, blood supply, and temperature regulation in the testicles, thereby impacting sperm count, quality (morphology, fragmentation rate), and functionality (motility). It may even induce symptoms such as pain and testicular atrophy. The international standard treatment method is microscopic varicocelectomy, typically performed under general anesthesia. This requires patients to fast before surgery and necessitates recovery and fasting care postoperatively. The arterial blood pressure drop caused by anesthesia may obscure the fluctuation of the spermatic artery, making the precise intraoperative isolation and protection of the spermatic artery more challenging. Therefore, this study proposes and implements microscopic varicocelectomy under local anesthesia. This method facilitates rapid and precise identification of the fluctuating spermatic artery, reducing the risk of spermatic artery damage. It also provides more humane care for patients, reduces economic burden, and offers a new perspective on the treatment of varicocele.

Evaluation of propofol-based procedural sedation in pediatric hemato-oncological patients provided by physician assistants in anesthesia.

Procedural sedation and analgesia are required for painful hemato-oncological procedures such as lumbar and bone marrow punctures. At our institution, sedation with propofol and alfentanil is usually provided by Physician Assistants in Anesthesia. We evaluated the adverse events during the PSA program for children, provided by Physician Assistants in Anesthesia. We included pediatric patients meeting our criteria for deep sedation by a Physician Assistants in Anesthesia, scheduled for a hemato-oncological procedure at the Amalia Children's Hospital at the Radboudumc Nijmegen. The primary outcome was oxygen desaturation below 92% for more than 20 s. We prospectively collected data on demographics, current health problems, type of procedure, need for airway interventions, and hypotension. We collected data from 437 sedation sessions involving 71 patients. No oxygen desaturation below 92% lasting longer than 20 s occurred. In 2 cases, a jaw thrust was performed. No invasive airway techniques (oropharyngeal cannula, laryngeal mask, or intubation) were required. A significant drop in mean arterial pressure was seen in 2 out of 437 cases (0.5%). There was no occurrence of cardiopulmonary resuscitation or other adverse events such as aspiration or laryngeal spasm. Sedation and analgesia for short painful procedures in selected pediatric hemato-oncological units with a dedicated protocol may be safely provided by trained and certified Physician Assistants in Anesthesia.

A generalized reduced-order model for trans-stenotic pressure drop with and without a guidewire

Guidewire-based pressure measurement is essential for diagnosing coronary artery disease. However, the impact of the guidewire on local hemodynamics and diagnostic outcomes is not fully understood. In this study, we propose a generalized reduced-order model (ROM) to accurately predict the trans-stenotic pressure drop in arteries. A key advantage of this model is that the viscous term does not rely on empirical parameters, making it applicable to both scenarios with and without guidewire insertion, and across varying stenosis severities. The proposed model demonstrates good accuracy compared to 3D idealized numerical models, achieving an average prediction error of 3.61% for cases without a guidewire and 4.53% for cases with a guidewire. Furthermore, when applied to a patient-specific model, it achieves comparable or better results than previously published ROMs. Finally, this ROM is employed to investigate the shifting relative importance of different components of the trans-stenotic pressure drop at various stenosis severities, and to provide further insights into the guidewire’s influence on FFR measurements.

Reconstructive Endovascular Treatment of Compensative-Flow-Related Posterior Circulation Aneurysms With Anterior Circulation Artery Occlusion.

The aim of this study was to delineate the reconstructive endovascular treatment and periprocedural management of compensative-flow-related posterior circulation aneurysms with anterior circulation artery occlusion. A total of 87 patients were enrolled in this retrospective double-center cohort study from May 2011 to November 2023. The baseline demographics, aneurysm characteristics, etiology and status of anterior circulation artery occlusion, treatment modalities, anesthesia management, complications, and clinical and angiographic outcomes of the patients were retrospectively analyzed in this study. Atherosclerosis and moyamoya disease were found to be the two main etiologies of anterior circulation artery occlusion. The mean American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology scores were significantly higher in patients with posterior communicating artery trunk collaterals than those with posterior cerebral artery pial collaterals (P < .05). Treatment strategies included stent-assisted coiling (55, 63.2%), standard coiling (22, 25.3%), and flow diversion or flow diversion-assisted coiling (8, 9.2%). The overall rate of procedure-related ischemic and hemorrhagic complications (10.3%) was considered acceptable. The ischemic complication was significantly associated with a >20% drop in mean arterial pressure (P < .05) during the procedure. Finally, 86.2% of all patients showed a modified Rankin Scale score of 0 to 2 at the final clinical follow-up. Our study indicates that reconstructive endovascular treatments are feasible and effective strategies for compensative-flow-related posterior circulation aneurysms with anterior circulation artery occlusion. However, these treatments are associated with a risk of periprocedural ischemic complications, which can be reduced by collateral arterial assessment, appropriate periprocedural anesthesia management, and antiplatelet treatment.

Mechanical Circulatory Support Reduces Directly Recorded Renal Sympathetic Nerve Activity in an Ovine Model of Cardiogenic Shock

Cardiogenic shock (CS) following myocardial infarction carries a high mortality risk despite advancements in management. The use of mechanical circulatory support in CS has become an effective strategy to improve haemodynamics and prevent acute kidney injury. However, the mechanism of how kidney function improves is unclear. We hypothesised that mechanical support would inhibit renal sympathetic nerve activity (RSNA), mediating renal protection in CS. Experiments were conducted in two groups of anaesthetised female sheep. In one group, CS was induced (n=8) using injections of polystyrene microspheres into the left coronary artery under fluoroscopic guidance. After a 30-minute baseline period (post -embolisation), intravenous phenylephrine infusion at incremental doses was used to assess the baroreflex control of RSNA before pump insertion. When the pressures recovered to baseline values, the circulatory assist Impella pump was inserted into the left ventricle and run randomly at different levels (P0 min-P6 max) with two minutes at each pump level. The controls underwent the same protocol without embolisation (n=6). Coronary artery embolisation resulted in a drop in mean arterial pressure (MAP) of 21 ± 4 mmHg compared to baseline values (n=8). This was associated with a 67% increase in renal sympathetic nerve activity (RSNA) from 16 ± 5 to 21 ± 5 spikes/s (p=0.038; n=7). Circulatory support using Impella significantly increased MAP from 55 ± 4 mmHg to 68 ± 5 mmHg at pump level P6 (one-way ANOVA, p&lt;0.001). Incremental pump support resulted in a significant decrease in RSNA (p&lt;0.001). At pump level P6, RSNA was decreased by 25 ± 5 % compared to P0 (p&lt;0.001). Baroreflex curves predicted a 2% reduction in RSNA at P6 equivalent pressures in CS, which was significantly less than that observed with circulatory support (p=0.006). In the control cohort with no CS, the changes in MAP and RSNA from P0 to P6 were qualitatively similar to the CS cohort. MAP increased from 84 ± 9 to 94 ± 8 mmHg (one-way ANOVA, p&lt;0.001) and RSNA decreased by 13 ± 5 % at P6 (one-way ANOVA, p&lt;0.001). The expected reduction in RSNA with baroreflex assessment at equivalent pressures to P6 was 5% in controls, which was not significantly different to what was observed (p=0.065). Our data indicate that the use of Impella pumps in CS reduces RSNA, which may mediate improvements in kidney function. Interestingly, the renal sympathoinhibition with the Impella pump is greater than that with vasoactive agents alone. We gratefully acknowledge the granting support from Abiomed and the University of Auckland Faculty Research Development Fund. 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.

EFFICACY OF TOLAZOLINE AND VATINOXAN IN REDUCING ADVERSE EFFECTS OF BUTORPHANOL-AZAPERONE-MEDETOMIDINE IMMOBILIZATION IN ROCKY MOUNTAIN ELK (CERVUS CANADENSIS).

A mixture of butorphanol, azaperone, and medetomidine (BAM) is frequently used for immobilization of North American hoofstock. Common adverse effects include respiratory depression, hypoxemia, and bradycardia. In this nonblinded crossover study the efficacy of two a-2 adrenergic antagonists, tolazoline and vatinoxan, were evaluated in alleviating adverse effects of BAM in Rocky Mountain elk (Cervus canadensis). Early administration of these antagonists was hypothesized to cause an increase in heart rate, respiratory rate, partial pressure of oxygen (PaO2) and hemoglobin oxygen saturation (SpO2), as well as reduction in mean arterial blood pressure without affecting sedation levels. Eight captive adult female elk were immobilized on three separate occasions at least 14 d apart with 0.15 mg/kg butorphanol, 0.05 mg/kg azaperone, and 0.06 mg/kg medetomidine. Tolazoline (2 mg/kg IM), vatinoxan (3 mg/mg medetomidine IV) or sterile saline (2 ml IM) were administered 20 min postinduction. The BAM caused hypoxemia, bradycardia, and moderate hypertension, and because of the severe hypoxemia observed, all animals received intratracheal oxygen throughout immobilization. Heart rate, respiratory rate, rectal temperature, SpO2, PaO2, and systolic, diastolic, and mean arterial blood pressure were monitored every 5 min throughout the immobilization. Intramuscular tolazoline caused a brief but significant drop in mean arterial pressure compared with controls and a brief but nonsignificant increase in heart rate. Vatinoxan caused a significant drop in blood pressure and a brief significant increase in heart rate. Changes in respiratory rates and PaO2 were not observed with either antagonist; however, all animals received oxygen, which may have influenced this result. The depth of sedation was unchanged after administration of either drug.

Venoarterial Extracorporeal Membrane Oxygenation Implementation in Septic Shock Rat Model.

Septic shock, a global health concern, boasts high mortality rates. Research exploring the efficacy of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in septic shock remains limited. Our study aimed to establish a rodent model employing VA-ECMO in septic shock rats, assessing the therapeutic impact of VA-ECMO on septic shock. Nineteen Sprague-Dawley rats were randomly assigned to sham, septic shock, and (septic shock + VA-ECMO; SSE) groups. Septic shock was induced by intravenous lipopolysaccharides, confirmed by a mean arterial pressure drop to 25-30% of baseline. Rats in the SSE group received 2 hours of VA-ECMO support and 60 minutes of post-weaning ventilation. Sham and septic shock groups underwent mechanical ventilation for equivalent durations. Invasive mean arterial pressure monitoring, echocardiographic examinations, and blood gas analysis revealed the efficacy of VA-ECMO in restoring circulation and ensuring adequate tissue oxygenation in septic shock rats. Post-experiment pathology exhibited the potential of VA-ECMO in mitigating major organ injury. In summary, our study successfully established a stable septic shock rat model with the implementation of VA-ECMO, offering a valuable platform to explore molecular mechanisms underlying VA-ECMO's impact on septic shock.

Ruptura pankreasne pseudoaneurizme kao posledice hroničnog pankreatitisa - prikaz slučaja

Abstract: Introduction: Pseudoaneurysms of the pancreaticoduodenal arcade are rare, accounting for approximately 2% of all visceral artery aneurysms. They typically arise as complications of chronic pancreatitis, peptic ulcer disease, trauma, pancreatic and biliary surgery, or pancreas transplantation. Diagnosis often occurs only after rupture, leading to life-threatening internal bleeding. Bleeding may occur within a pseudocyst, with blood passing through the Vater's papilla into the digestive tract, or may result in the formation of a retroperitoneal hematoma that can rupture into the abdominal cavity, causing hemoperitoneum. The cell-saver is a tool that can be utilized for intraoperative blood cell salvage and autologous transfusions. Case Report: Our patient, a 54-year-old male, an untreated alcoholic with no prior medical history or documented treatment, presented to the Clinic for Emergency Surgery at the University Clinical Center of Serbia with a sudden onset of upper abdominal pain. A quick ultrasound of the abdomen was performed, followed by an urgent CT scan of the chest and abdomen, revealing a hematoma extending from the right retroperitoneum and mesentery of the intestine, measuring 150x109x180mm in diameter, with signs of active bleeding in the region beneath the pancreas, indicative of hemoperitoneum. Due to hemodynamic instability, accompanied by a drop in arterial blood pressure and hemoglobin levels, an urgent laparotomy was performed. Active bleeding was identified from a ruptured pseudoaneurysm originating from the pancreaticoduodenal arcade. Hemostasis was achieved followed by tamponade, and the tampons were removed 30 hours post-surgery. The patient remained hemodynamically stable thereafter, recovered well from the surgery, and was discharged home in good general condition. Intraoperatively, we utilized the Cell-saver to collect the patient's blood and subsequently administered autologous transfusion. Conclusion: In patients with chronic pancreatitis presenting with sudden abdominal pain and hemodynamic instability accompanied by a drop in arterial pressure, hemoglobin, and hematocrit levels, the possibility of a ruptured pseudoaneurysm in the pancreatic or peripancreatic region should be considered. Timely diagnosis and prompt surgical intervention are crucial for a successful outcome. Effective collaboration among radiologists, anesthesiologists, and surgeons is essential. The utilization of the Cell-saver system significantly aids in maintaining cardiac output and hemodynamic stability in these patients.

The Role of Intraoperative and Early Postoperative Blood Pressure Variations, Fluid Balance and Inotropics in Fibula Free Flap Head and Neck Reconstruction: A Retrospective Analysis.

In head and neck reconstructive surgery, postoperative complications are a well-known concern. We examined 46 patients who underwent ablative surgery and received fibula free flap reconstruction. The main focus was to assess the influence of intraoperative blood pressure fluctuations and the administration of inotropic drugs on complications, either related to the flap or systemic, serving as the primary endpoint. Utilizing logistic regression models, we identified that intraoperative mean arterial blood pressure (MAP) drops did not correlate with the occurrence of either flap-related complications (MAP < 70, p = 0.79; MAP < 65, p = 0.865; MAP < 60, p = 0.803; MAP < 55, p = 0.937) or systemic medical complications (MAP < 70, p = 0.559; MAP < 65, p = 0.396; MAP < 60, p = 0.211; MAP < 55, p = 0.936). The occurrence of flap-related complications significantly increased if a higher dosage of dobutamine was administered (median 27.5 (IQR 0-47.5) vs. 62 (38-109) mg, p = 0.019) but not if norepinephrine was administered (p = 0.493). This correlation was especially noticeable given the uptick in complications associated with fluid overload (3692 (3101-4388) vs. 4859 (3555-6216) mL, p = 0.026). Intraoperative and immediate postoperative blood pressure fluctuations are common but are not directly associated with flap-related complications; however, dobutamine application as well as fluid overload may impact flap-specific complications.

Abstract 371: Physiological Predictors of Cerebral Oxygenation During Hemorrhage in Swine

Introduction: Measurements of cerebral oxygenation (rSO 2 ) using near-infrared spectroscopy (NIRS) have been used to predict survival in retrospective clinical studies. However, the physiology underlying changes in rSO 2 during critical states such as hemorrhage is not completely understood. This analysis examined the effect of blood pressures, intracranial pressure, and heart rate on rSO 2 . Methods: Eight swine were instrumented with invasive pressure catheters in the aorta, right atrium, and cerebrum and underwent a pressure-targeted arterial hemorrhage protocol. Animals were bled at a rate of 20mL/min to a target diastolic pressure of 35 mmHg. Brief periods of increased baseline airway pressure (15 cm H 2 O) were introduced to cause transient drops in arterial blood pressure. The aortic pressure waveform was used to identify individual heartbeats. The first 100 heartbeats represent baseline data, while heart beats 4900-5000 (time from start of bleed; 40±7 min) capture data late into the bleed for all animals. Data from 53,315 heart beats were entered into a regression model: rSO 2 = mean diastolic aortic pressure + mean diastolic right atrial pressure + intracranial pressure + heart rate + animal. Results: The hemorrhage reduced diastolic aortic pressure from 61.7±9.6 (heart beats 1-100) to 35.0±9.2 mmHg (heart beats 4900-5000), increased right atrial pressure from 4.1±3.6 to 4.9±6.9 mmHg, reduced intracranial pressure from 33.6±23.2 mmHg to 16.3±2.5 mmHg, and increased heart rate from 101±14 to 144±40 beats/min. Output from the regression model (Table 1) shows that mean diastolic aortic pressure, but not right atrial pressure, intracranial pressure or heart rate, is a significant predictor of rSO 2 . Conclusions: rSO 2 values are largely driven by arterial blood pressure and may serve as a useful non-invasive tool as a surrogate for arterial blood pressure during hemorrhage. Further work should investigate the use of this technology to provide real-time feedback.

Recombinant Human Diamine Oxidase Against Histamine Induced Shock - Implications for Mast Cell Activation Syndrome

Background and Objective:Mastocytosis patients suffer from a clonal increase in mast cells which produce and release excessive amounts of histamine even under stable conditions (Keyzer et al. 1983). Unfortunately, symptom control with new kinase inhibitors is variable and modest at best. Mast cell activation syndrome may further enhance histamine release which can result in recurrent shocks (Böhm et al. 2019), or severe, protracted anaphylaxis refractory to epinephrine (Grafeneder et al. 2022). Previously we demonstrated that recombinant human diamine oxidase (rhDAO) fully degrades 100-fold elevated histamine concentrations in plasma samples from mastocytosis patients. In vivo rhDAO, with a mutated heparin binding motif (mHBM), was able to digest massively increased histamine levels, thereby improving indirect measures of shock such as a temperature drop in mice (Karer et al. 2022). As mice are insensitive to histamine (intravenous LD50 of 385mg/kg in mice compared with 0.18mg/kg in guinea pigs), this unfortunately limits their translational value. To assess the therapeutic potential of rhDAO_mHBM, we tested its efficacy for the prevention and treatment of histamine induced shock in guinea pigs, the only histamine sensitive rodent species. Methods:Guinea pigs received continuous intravenous infusions of 8 µg/kg/min histamine to model its release from activated circulating basophils or subcutaneous injections of 1mg/kg histamine to mimic peripheral histamine release by mast cells. We used intramuscular injections of 5µg/kg adrenaline as a benchmark, because it is recommended in guidelines for the treatment of anaphylaxis, although its efficacy had never been proven. Infusions of rhDAO_mHBM were given either prophylactically before- or therapeutically after - symptom onset. Mean arterial pressure was measured intra-arterially and rhDAO_mHBM levels were quantified by enzyme immunoassay and histamine concentrations by a liquid chromatography -tandem mass spectrometry (LC-MS/MS) method. The primary outcome variable was prevention of shock as defined by a &amp;gt;=30% drop in mean arterial blood pressure. Results:Guinea pigs pretreated with 4 mg/kg rhDAO_mHBM showed lower mean heart rate (p&amp;lt;0.01) and higher body core temperatures at the end of the intravenous histamine infusions compared to controls (p&amp;lt;0.05). Histamine infusions increased median urinary excretion of histamine and N-methyl-histamine 8.6- and 4.0-fold (p&amp;lt;0.05), respectively. Pretreatment with 4 mg/kg rhDAO_mHBM reduced urinary histamine (p&amp;lt;0.01) and N-methyl-histamine (p&amp;lt;0.01) concentrations compared with controls. Subcutaneous injections of 1 mg/kg histamine induced shock within 20 minutes in all control animals, and the experiments had to be terminated prematurely in several animals. Intramuscular injection of 5mcg/kg adrenaline (similar to human adrenaline auto-injector doses) after symptom onset was unable to prevent shock, confirming its lack of efficacy demonstrated previously in an anaphylaxis model in dogs (Mink et al. 2004). In contrast, prophylactic infusions of 4-8mg/kg rhDAO_mHBM prevented hypotensive shock in all treated animals (p&amp;lt;0.01). After an initial histamine induced drop in blood pressure, 8mg/kg rhDAO_mHBM restored blood pressure and prevented shock in all animals when injected at the time of symptom occurrence (p&amp;lt;0.01 Chi2 test). Figure 1 demonstrates the median drop in blood pressure and development of shock (indicated by the dashed line) by subcutaneous injection of 1mg/kg histamine (black squares), and the prevention of shock by rhDAO-mHBM given before (blue up triangles) or after (red circles) histamine injections. Conclusion: This is the first demonstration of the beneficial effects of rhDAO_mHBM in a histamine-sensitive species. rhDAO_mHBM is a novel therapeutic approach targeting histamine excess which effectively prevented shock, in contrast to intramuscular epinephrine. As the mechanism of action is not species specific, these findings can be translated from guinea pigs to humans: it will help to select optimal dosing of rhDAO_mHBM during clinical development for the prophylaxis in - and treatment of - mastocytosis patients suffering from histamine induced symptoms or mast cell activation syndrome, or patients with anaphylaxis induced by asparaginase, plasma products or other medications.

Abstract Number ‐ 54: First Fully Automated Robotic Transcranial Doppler Optimization of Cerebral Blood Flow During Cardiac Revascularization Surgery

Introduction Current technologies including EEG and near infrared pulse oximetry for non‐invasive monitoring of cerebral blood flow during cardiac surgery have proven inadequate for perioperative stroke risk mitigation. Cerebral arterial flow velocity is an excellent indicator of cerebral blood flow making transcranial doppler ultrasound (TCD) an excellent alternative technology for operating room continuous cerebral monitoring. To date, TCD utilization in the operating room has been limited due to frequent movement‐related loss of signal requiring nearly continuous manual probe readjustment. The recent development of fully autonomous robotic TCD (aTCD) has overcome these technical limitations, opening the door for real‐time continuous noninvasive cerebral blood flow monitoring with simultaneous emboli detection. Methods A 47‐year‐old female patient was found to have preoperative complete occlusion of the proximal brachiocephalic artery producing a double cerebral steal phenomenon with retrograde flow in the right internal carotid and vertebral arteries into the subclavian. A preoperative aTCD study disclosed baseline markedly diminished blood flow in the right middle cerebral artery (MCA) fed exclusively by small‐diameter collaterals via the circle of Willis.Intraoperatively, robotic aTCD was used to continuously monitor blood flow in the bilateral MCAs and perform emboli detection. In response to movement‐related signal loss, the robotic aTCD autonomously adjusted the probe position to maintain continuous MCA insonation. Results Shortly after intubation, a small drop in mean arterial pressure led to a near‐total loss of cerebral perfusion to the entire right hemisphere. This perfusion decrease was detected by aTCD, triggering the anesthesiologist to rapidly correct blood pressure to ensure adequate cerebral perfusion as confirmed by the robotic system. The patient was then placed on bypass pump with deployment of a temporary Y‐graft from the pump to the subclavian artery distal to the vertebral branch point and to the aorta to temporarily reverse the double cerebral steal. Coronary bypass was then performed, throughout which cerebral flow velocities were monitored continuously with aTCD and maintained in the safe cerebral perfusion range by adjusting pump pressures. Following a three‐vessel coronary bypass graft, permanent brachiocephalic artery bypass grafts were placed from the proximal aorta to the right subclavian and the proximal common carotid artery.Postoperative aTCD disclosed correction of the previously diminished blood flow detected in the right MCA preoperatively. Brain MRI postoperatively confirmed the absence of acute stroke. Conclusions This case represents the first use of robotic aTCD for real time continuous cerebral blood flow monitoring and optimization during complex cardiac surgery. Our experience suggests that aTCD may improve patient outcomes, particularly during high‐risk cardiac surgical and interventional procedures. Further studies of this promising technology are now needed.

Comparison of effect of prophylactic administration of ondansetron and placebo on prevention of post induction hypotension in elderly patients undergoing surgery in general anesthesia

Background: Post-induction hypotension is a frequently encountered complication seen particularly in elderly population. Hypotension, by impairing vital organ perfusion, increases the morbidity and mortality of the patients. prophylactic use of ondansetron in preventing hypotension after induction of general anaesthesia in elderly patients , hence getting the benefit of preventing both hypotension and postoperative nausea and vomiting by the use of a single drug.&#x0D; Subjects and method: This randomized controlled clinical trial was carried out in the operation theaters of general surgery, Mayo Hospital, Lahore, from 09-09-2017 to 09-09-2018. A total of 80 patients who were to undergo general anaesthesia for elective general surgical procedures were recruited for this study. After taking informed consent, the patients were randomly divided into two groups. Patients in group A received ondansetron and those in group B received placebo prior to the induction of anaesthesia. Efficacy was labeled in terms of absence of hypotension i.e. a drop in mean arterial pressure of no more than 25% of baseline at 1, 3, 5, 9 and 11 minutes after induction of anaesthesia. The data was recorded on a predesigned proforma. Statistical analysis was done using SPSS version 21.&#x0D; Results: Both groups were comparable in terms of age, gender, ASA status, BMI and weight. Efficacy was seen in 19 (47.50%) cases managed by ondansetron vs. 10 (25%) in placebo group (p = 0.03). There was significant difference of efficacy in patients with age between 60 to 70 years where 63.63% patients in the Group A effectively maintained their blood pressure (p=0.02). Patients having age 70 years or above did not show statistically significant difference. History of hypertension made no impact on the efficacy of ondansetron for maintaining blood pressure after induction (p=0.53)&#x0D; Keywords: &#x0D; Ondansetron, Efficacy, Hypotension

A total closed chest swine model of acute myocardial infarction-related cardiogenic shock: A critical double coronary sub-occlusion approach

The management of acute myocardial infarction-related cardiogenic shock (AMICS) represents a significant challenge, with mortality rates remaining high (40–60%), despite recent advances. Current animal models of myocardial infarction are either associated with a very high rate of per-procedure malignant arrhythmia, or with very low impairment of hemodynamic parameters, or with the inability to have complete coronary reperfusion. We sought to develop a closed chest and clinically relevant large animal model of severe AMICS, with high survival rate. Adult pigs were anaesthetized and mechanically ventilated. Percutaneous cardiac catheterization was performed under fluoroscopy. Advanced left ventricular dysfunction was induced by 120 minutes of critical sub-occlusion of the proximal left anterior descending coronary artery and the mid circumflex artery. A thorough hemodynamic assessment was obtained by invasive and non-invasive monitoring devices. Repeated blood samples were obtained to determine blood gas parameters, lactate, and haemoglobin concentration. After death, the heart was retrieved for further histological analyses. All animals (n = 12) developed significant circulatory failure associated with AMICS upon reperfusion and beyond. No animal died during the ischemia process. However, all animals that did not benefited from vasopressor support (“sham” group, n = 4) spontaneously died within 30 minutes of reperfusion, confirming the severity of the model. Cardiogenic shock was characterized by a drop in mean arterial pressure below 60 mmHg (58 ± 5 mmHg at 120 min of ischemia), a significant decrease in mean cardiac output (−44% from 5.7 ± 0.4 at baseline to 3.2 ± 0.4 at 120 minutes of ischemia) and SvO2 (−32% from 57 ± 8 at baseline to 39 ± 6 at 120 minutes of ischemia) and a significant increase in left ventricle end-diastolic pressure (LVEDP) (+110% from 10 ± 3 at baseline to 21 ± 3 at 120 minutes of ischemia). CO2 gap and coronary sinus venous oxygen saturation increased significantly upon ischemia and reperfusion and remained elevated throughout (P ≤ 0.001 for all comparisons). Myocardial samples corroborated extensive cellular necrosis and inflammatory infiltrates. We present, for the first time, a stable and clinically relevant model of severe AMICS obtained by critical double coronary sub-occlusion. The greater severity of the model did not lead to an increase in the frequency of malignant arrythmias and per-procedure mortality.

Construction of an Early Alert System for Intradialytic Hypotension before Initiating Hemodialysis Based on Machine Learning

Introduction: Intradialytic hypotension (IDH) is prevalent and associated with high hospitalization and mortality rates. The purpose of this study was to explore the risk factors for IDH and use artificial intelligence to establish an early alert system before hemodialysis sessions to identify patients at high risk of IDH. Materials and Methods: We obtained data on 314,534 hemodialysis sessions conducted at Sichuan Provincial People’s Hospital from the renal disease treatment information system. IDH was defined as a systolic blood pressure drop ≥20 mm Hg, a mean arterial pressure drop ≥10 mm Hg during dialysis, or the occurrence of clinical hypotensive events requiring nursing intervention. After pre-processing, the data were randomly divided into training (80%) and testing (20%) sets. Four interpolation methods, three feature selection methods, and 18 machine learning algorithms were used to construct predictive models. The area under the receiver operating characteristic curve (AUC) was the main indicator for evaluating the performance of the models, while Shapley Additive ExPlanation was used to explain the contribution of each variable to the best predictive model. Results: A total of 3,906 patients and 314,534 dialysis sessions were included, of which 142,237 cases showed IDH (incidence rate, 45.2%). Nineteen parameters were identified through artificial intelligence feature screening. They included age, pre-dialysis weight, dry weight, pre-dialysis blood pressure, heart rate, prescribed ultrafiltration, blood cell counts (neutrophil, lymphocyte, monocyte, eosinophil, lymphocyte, and platelet counts), hematocrit, serum calcium, creatinine, urea, glucose, and uric acid. Random forest, gradient boosting, and logistic regression were the three best models, and the AUCs were 0.812 (95% confidence interval [CI], 0.811–0.813), 0.748 (95% CI, 0.747–0.749), and 0.743 (95% CI, 0.742–0.744), respectively. Conclusion: Our dialysis software-based artificial intelligence alert system can be used to predict IDH occurrence, enabling the initiation of relevant interventions.

Two syringes technique for spinal anesthesia to prevent hypotension in patients undergoing elective cesarean section

Aims: To compare the incidence of hypotension after intrathecal administration of hyperbaric bupivacaine and fentanyl in two different syringes against standard injection of mixed fentanyl with hyperbaric bupivacaine.&#x0D; Methods: This was a prospective comparative study conducted in 174 parturients undergoing elective caesarean section at Paropakar Maternity &amp; Women’s Hospital. Hemodynamic effects and characteristics of block were monitored and recorded and compared between the two groups, group S (single syringe) and group D (double syringe).&#x0D; Results: The incidence of hypotension was almost similar in the two groups but the drop in systolic blood pressure and mean arterial pressure at 5 minutes and 7.5 minutes after subarachnoid block was significant in group S as compared to group D (p&lt;0.005 and p&lt;0.005 respectively).&#x0D; Conclusion: Hyperbaric bupivacaine with fentanyl, which when injected separately without mixing, is associated with lesser incidence of hypotension following subarachnoid block.

Dynamic Arterial Elastance to Predict Mean Arterial Pressure Decrease after Reduction of Vasopressor in Septic Shock Patients.

After fluid status optimization, norepinephrine infusion represents the cornerstone of septic shock treatment. De-escalation of vasopressors should be considered with caution, as hypotension increases the risk of mortality. In this prospective observational study including 42 patients, we assess the role of dynamic elastance (EaDyn), i.e., the ratio between pulse pressure variation and stroke volume variation, which can be measured noninvasively by the MostCare monitoring system, to predict a mean arterial pressure (MAP) drop &gt; 10% 30 min after norepinephrine reduction. Patients were divided into responders (MAP falling &gt; 10%) and non-responders (MAP falling &lt; 10%). The receiver-operating-characteristic curve identified an area under the curve of the EaDyn value to predict a MAP decrease &gt; 10% of 0.84. An EaDyn cut-off of 0.84 predicted a MAP drop &gt; 10% with a sensitivity of 0.71 and a specificity of 0.89. In a multivariate logistic regression, EaDyn was significantly and independently associated with MAP decrease (OR 0.001, 95% confidence interval 0.00001-0.081, p &lt; 0.001). The nomogram model for the probability of MAP decrease &gt; 10% showed a C-index of 0.90. In conclusion, in a septic shock cohort, EaDyn correlates well with the risk of decrease of MAP &gt; 10% after norepinephrine reduction.

824 HEMODYNAMIC EFFECTS OF LEVOSIMENDAN IN PATIENTS WITH ACUTE HEART FAILURE AND SEVERE RENAL FAILURE

Abstract Background The inodilator levosimendan has shown improved outcomes in acute heart failure (AHF) and cardiac surgery. Its hemodynamic effect is persistent, owing to a long (70-80 hours) elimination half-life of its active metabolites. No robust data is available of the use of levosimendan in patients with severe renal failure (SRF), thus its use is contraindicated in patients with estimated glomerular filtration rate (eGFR≤30 mL/min). Hypothesis Different pharmacokinetics due to renal failure may alter levosimendan active metabolites elimination, causing more pronounced hemodynamic effects. We aimed to characterize the hemodynamic effect of levosimendan in a real-world cohort of SRF patients. Methods We reviewed patients who received levosimendan (12.5 mg) for AHF or cardiogenic shock in our CICU (N=132), excluding those without invasive hemodynamics (n=85), and those without data before and during levosimendan infusion (n=11), a total of 36 patients were finally included in this analysis. We compared hemodynamics before and during levosimendan infusion in the study cohort with CKD-EPI eGFR≤30 mL/min/1.73 m2 or CRRT and those without. Results Patients with low eGFR (n=11) were older, they had similar LVEF and invasive hemodynamics before levosimendan infusion to the higher eGFR cohort. Visual inspection of the LOESS regression plots (Figure) revealed an higher drop in mean arterial pressure (MAP) and diastolic arterial pressure (DAP) in the low eGFR cohort. The maximum drop was observed at day 4 from levosimendan initiation, invasive hemodynamics at this timepoint revealed a lower DAP (44.6±8.8 vs 62.6±11.9 mmHg; p=0.014) and a tendentially lower MAP (73.6±5.5 vs 84.4±11.5 mmHg; p=0.079) while systolic arterial pressure (125.0±24.6 vs 121.3±21.8 mmHg; p=0.779), cardiac index (2.1±0.5 vs 2.5±0.7 L/m2; p=0.211), and mean pulmonary arterial pressure (25.8±8.3 vs 24.8±9.6 mmHg; p=0.844) did not differ between groups. In-hospital death was not different in the two cohorts (27.3 vs 16.0%; p=0.650). Conclusions Patient with eGFR≤30 mL/min/1.73 m2 demonstrated a higher drop in DAP and MAP four days after levosimendan infusion start, without impact on hospital mortality. These findings may suggest a more pronounced hemodynamic effect of levosimendan in patients with SRF, possibly due to altered pharmacokinetics of its active metabolites.

A syncope collared

Carotid sinus syncope is a temporary, exaggerated circulatory response to carotid massage, characterized by marked drop in arterial pressure, and varying degree of bradycardia, or even asystole lasting for several seconds, resulting in short lasting loss of consciousness. A related reflex mediated disorder is a fainting precipitated by a parapharyngeal space-occupying lesion, manifests in prolonged episodes of hemodynamic instability. We report a case, where the hemodynamic features of the syncope are well documented. The case illustrates the potential overlap between pulseless electrical activity and syncope, and a simple noninvasive solution for the frightening symptoms is also suggested.

Comparison of optical measurements of critical closing pressure acquired before and during induced ventricular arrhythmia in adults.

.Significance: The critical closing pressure (CrCP) of cerebral circulation, as measured by diffuse correlation spectroscopy (DCS), is a promising biomarker of intracranial hypertension. However, CrCP techniques using DCS have not been assessed in gold standard experiments.Aim: CrCP is typically calculated by examining the variation of cerebral blood flow (CBF) during the cardiac cycle (with normal sinus rhythm). We compare this typical CrCP measurement with a gold standard obtained during the drops in arterial blood pressure (ABP) caused by rapid ventricular pacing (RVP) in patients undergoing invasive electrophysiologic procedures.Approach: Adults receiving electrophysiology procedures with planned ablation were enrolled for DCS CBF monitoring. CrCP was calculated from CBF and ABP data by three methods: (1) linear extrapolation of data during RVP (; the gold standard); (2) linear extrapolation of data during regular heartbeats (); and (3) fundamental harmonic Fourier filtering of data during regular heartbeats ().Results: CBF monitoring was performed prior to and during 55 episodes of RVP in five adults. and demonstrated agreement (, (95%CI, 0.72 to 1.38). Agreement between and was worse; was higher than (mean ± SD; ).Conclusions: Our results suggest that DCS-measured CrCP can be accurately acquired during normal sinus rhythm.