Changes In Arterial Pressure Research Articles

Statistical properties of cerebral near infrared and intracranial pressure-based cerebrovascular reactivity metrics in moderate and severe neural injury: a machine learning and time-series analysis

BackgroundCerebrovascular reactivity has been identified as a key contributor to secondary injury following traumatic brain injury (TBI). Prevalent intracranial pressure (ICP) based indices of cerebrovascular reactivity are limited by their invasive nature and poor spatial resolution. Fortunately, interest has been building around near infrared spectroscopy (NIRS) based measures of cerebrovascular reactivity that utilize regional cerebral oxygen saturation (rSO2) as a surrogate for pulsatile cerebral blood volume (CBV). In this study, the relationship between ICP- and rSO2-based indices of cerebrovascular reactivity, in a cohort of critically ill TBI patients, is explored using classical machine learning clustering techniques and multivariate time-series analysis.MethodsHigh-resolution physiologic data were collected in a cohort of adult moderate to severe TBI patients at a single quaternary care site. From this data both ICP- and rSO2-based indices of cerebrovascular reactivity were derived. Utilizing agglomerative hierarchical clustering and principal component analysis, the relationship between these indices in higher dimensional physiologic space was examined. Additionally, using vector autoregressive modeling, the response of change in ICP and rSO2 (ΔICP and ΔrSO2, respectively) to an impulse in change in arterial blood pressure (ΔABP) was also examined for similarities.ResultsA total of 83 patients with 428,775 min of unique and complete physiologic data were obtained. Through agglomerative hierarchical clustering and principal component analysis, there was higher order clustering between rSO2- and ICP-based indices, separate from other physiologic parameters. Additionally, modeled responses of ΔICP and ΔrSO2 to impulses in ΔABP were similar, indicating that ΔrSO2 may be a valid surrogate for pulsatile CBV.ConclusionsrSO2- and ICP-based indices of cerebrovascular reactivity relate to one another in higher dimensional physiologic space. ΔICP and ΔrSO2 behave similar in modeled responses to impulses in ΔABP. This work strengthens the body of evidence supporting the similarities between ICP-based and rSO2-based indices of cerebrovascular reactivity and opens the door to cerebrovascular reactivity monitoring in settings where invasive ICP monitoring is not feasible.

Hemodynamic impact of ephedrine on hypotension during general anesthesia: a prospective cohort study on middle-aged and older patients

BackgroundEphedrine is a mixed α- and β-agonist vasopressor that is frequently used for the correction of hypotension during general anesthesia. β-responsiveness has been shown to decrease with age; therefore, this study aimed to determine whether aging would reduce the pressor effect of ephedrine on hypotension during general anesthesia.MethodsSeventy-five patients aged ≥ 45 years were included in this study, with 25 patients allocated to each of the three age groups: 45–64 years, 65–74 years, and ≥ 75 years. All patients received propofol, remifentanil, and rocuronium for the induction of general anesthesia, followed by desflurane and remifentanil. Cardiac output (CO) was estimated using esCCO technology. Ephedrine (0.1 mg/kg) was administered for the correction of hypotension. The primary and secondary outcome measures were changes in the mean arterial pressure (MAP) and CO, respectively, at 5 min after the administration of ephedrine. ResultsThe administration of ephedrine significantly increased MAP (p < 0.001, mean difference: 8.34 [95% confidence interval (CI), 5.95–10.75] mmHg) and CO (p < 0.001, mean difference: 7.43 [95% CI, 5.20–9.65] %) across all groups. However, analysis of variance revealed that the degree of elevation of MAP (F [2, 72] = 0.546, p = 0.581, η2 = 0.015 [95% CI, 0.000–0.089]) and CO (F [2, 72] = 2.023, p = 0.140, η2 = 0.053 [95% CI, 0.000–0.162]) did not differ significantly among the groups. Similarly, Spearman’s rank correlation and multiple regression analysis revealed no significant relation between age and the changes in MAP or CO after the administration of ephedrine.ConclusionThe administration of ephedrine significantly increased MAP and CO; however, no significant correlation with age was observed in patients aged > 45 years. These findings suggest that ephedrine is effective for the correction of hypotension during general anesthesia, even in elderly patients.Trial registrationUMIN-CTR (UMIN000045038; 02/08/2021).

Microvascular decompression can effectively reduce arterial blood pressure in patients with Trigeminal Neuralgia

BackgroundMicrovascular decompression (MVD) has been used in the treatment of Trigeminal Neuralgia (TN) and arterial hypertension (HTN). Results of several reports have supported its clinical effectiveness, however, little attention has been paid on arterial blood pressure changes caused by MVD in patients with TN. MethodsIn this single-center retrospective study, a cohort of 80 patients with TN who underwent MVD between 2021 and 2022 had been reviewed. Clinical data such as age, gender, pain duration, operation time, side and range of pain, HTN history, treatment history, VAS score, mean arterial pressure (MAP), and nausea or vomiting after operation were collected and analyzed via Linear regression to select possible related factors. Then, multiple linear regression of the possible predictors was used to identify the variables that significantly predicted MAP reduction. ResultsThe VAS scores of TN patients after MVD surgery was significantly lower than that before operation, irrespective of the gender, side and range of pain, HTN history, RF history, and PONV (Wilcoxon test, P < 0.001). MVD can significantly decreased the blood pressure of TN patients, without interference from other factors. (MAP reduction ratio=14.46% ± 12.32%) (paired t-test, P < 0.001). The univariate and Multiple linear regression analysis showed that the preoperative MAP was significantly related to MAP reduction ratio (P < 0.001). ConclusionsIn patients with TN, MVD can significantly decrease arterial blood pressure. Blood pressure reductions were more prominent when cases with higher preoperative MAP.

Impaired renal autoregulation and pressure-natriuresis: any role in the development of heart failure in normotensive and angiotensin II-dependent hypertensive rats?

The aim of the present study was to assess the autoregulatory capacity of renal blood flow (RBF) and of the pressure-natriuresis characteristics in the early phase of heart failure (HF) in rats, normotensive and with angiotensin II (ANG II)-dependent hypertension. Ren-2 transgenic rats (TGR) were employed as a model of ANG II-dependent hypertension. HF was induced by creating the aorto-caval fistula (ACF). One week after ACF creation or sham-operation, the animals were prepared for studies evaluating in vivo RBF autoregulatory capacity and the pressure-natriuresis characteristics after stepwise changes in renal arterial pressure (RAP) induced by aortic clamping. In ACF TGR the basal mean arterial pressure, RBF, urine flow (UF), and absolute sodium excretion (UNaV) were all significantly lower tha n in sham-operated TGR. In the latter, reductions in renal arterial pressure (RAP) significantly decreased RBF whereas in ACF TGR they did not change. Stepwise reductions in RAP resulted in marked decreases in UF and UNaV in sham-operated as well as in ACF TGR, however, these decreases were significantly greater in the former. Our data show that compared with sham-operated TGR, ACF TGR displayed well-maintained RBF autoregulatory capacity and improved slope of the pressure-natriuresis relationship. Thus, even though in the very early HF stage renal dysfunction was demonstrable, in the HF model of ANG II-dependent hypertensive rat such dysfunction and the subsequent HF decompensation cannot be simply ascribed to impaired renal autoregulation and pressure-natriuresis relationship.

Stiffness pulsation of the human brain detected by non-invasive time-harmonic elastography.

Introduction: Cerebral pulsation is a vital aspect of cerebral hemodynamics. Changes in arterial pressure in response to cardiac pulsation cause cerebral pulsation, which is related to cerebrovascular compliance and cerebral blood perfusion. Cerebrovascular compliance and blood perfusion influence the mechanical properties of the brain, causing pulsation-induced changes in cerebral stiffness. However, there is currently no imaging technique available that can directly quantify the pulsation of brain stiffness in real time. Methods: Therefore, we developed non-invasive ultrasound time-harmonic elastography (THE) technique for the real-time detection of brain stiffness pulsation. We used state-of-the-art plane-wave imaging for interleaved acquisitions of shear waves at a frequency of 60Hz to measure stiffness and color flow imaging to measure cerebral blood flow within the middle cerebral artery. In the second experiment, we used cost-effective lineby-line B-mode imaging to measure the same mechanical parameters without flow imaging to facilitate future translation to the clinic. Results: In 10 healthy volunteers, stiffness increased during the passage of the arterial pulse wave from 4.8% ± 1.8% in the temporal parenchyma to 11% ± 5% in the basal cisterns and 13% ± 9% in the brain stem. Brain stiffness peaked in synchrony with cerebral blood flow at approximately 180 ± 30ms after the cardiac R-wave. Line-by-line THE provided the same stiffness values with similar time resolution as high-end plane-wave THE, demonstrating the robustness of brain stiffness pulsation as an imaging marker. Discussion: Overall, this study sets the background and provides reference values for time-resolved THE in the human brain as a cost-efficient and easy-touse mechanical biomarker associated with cerebrovascular compliance.

Dexmedetomidine versus propofol: An effective combination with ketamine for adult procedural sedation: A randomized clinical trial

BackgroundRecently, drug combination protocols have been preferred over single drugs in procedural sedation and analgesia (PSA). This study aimed to compare the effectiveness and hemodynamic profile of ketamine-dexmedetomidine (ketodex) and ketofol as drug combinations with ketamine as a single medication for PSA in the emergency department (ED). MethodsThis prospective, randomized, double-blind clinical trial was performed among adult patients (≥18 years) requiring PSA for a painful procedure in the ED. 135 patients were enrolled and assigned into three equal groups to receive either ketodex, ketofol, or ketamine. Additional ketamine was used as a rescue agent for inadequate sedation in three groups. Oxygen saturation, heart rate, and blood pressure were recorded from baseline until 120 min after induction of PSA. Adverse events, hemodynamic variables, induction, and recovery time were recorded and compared between groups. ResultsThe mean age of the patients was 38.16 ± 19.09 years and no differences were observed between the three groups in terms of demographic variables, pain scores, and procedures between the three groups. Respiratory events had similar incidences between the three groups. The O2 reduction was less in the Ketodex group in comparison with Ketofol and Ketamine groups (1.9%, 6.5%, and 3.8%, P = 0.015). No patient needed endotracheal intubation. Changes in mean arterial pressure from the baseline in Ketamine and Ketofol groups compared to Ketodex was higher (difference was 12.9 mmHg [95% CI, 9.5 to 20.3] and 8.6 mmHg [95% CI, 3.4 to 13.7]. Tachycardia in the Ketamine group had a significantly higher incidence. The recovery time was statistically shorter in the Ketofol group in comparison with other groups. The differences between Ketofol with Ketamine and Ketodex groups were 9.8 min (95% CI, [2.5 to 17.1]) and 8.3 min (95% CI, [1.5 to 15.1]). ConclusionKetodex, as well as ketofol, were effective and safe combinations with good recovery profiles and hemodynamic stability for adult PSA in ED.

Tube-first Technique as a Conduit for Easy and Fast Nasal Fiberoptic Intubation

Background: Classical nasal fiberoptic bronchoscope intubation may be a challenging and lengthy procedure with a 1-10% failure rate. Objectives: This study aimed to compare among patients with difficult airway intubation undergoing general anesthesia, the safety, and efficacy of Tube-First (TF) nasal fiberoptic bronchoscope intubation against the Classic (CL) procedure. Methods: This single-blinded, parallel-group, randomized trial enrolled 40 adult patients with known difficult airways and scheduled for surgery under general anesthesia. The patients were randomly allocated into two (n=20 each) patient groups. In the CL group, the endotracheal tube and fiberoptic bronchoscope were inserted together through the nostril; in the TF group, the endotracheal tube insertion preceded the fiberoptic bronchoscope. In both groups, the bronchoscope was used to visualize the vocal cords and removed after ensuring the endotracheal tube position. The primary (efficacy) outcomes were the time elapsing from the bronchoscope insertion and visualizing the vocal cords (T1) and the time elapsing from the bronchoscope advancing initiation to its removal (T2). The secondary (safety) outcomes included oxygen saturation and hemodynamic parameters during the procedure. Results: The TF group showed a significant T1 and T2 mean reduction compared to those of the CL group (37.15 ± 3.87 and 64.25 ± 8.28 vs. 55.05±4.52 and 88.25±5.49 seconds, respectively; p &lt; 0.0001). The oxygen saturation was comparable in both groups with no desaturation (SpO2 &lt; 90%) cases. The heart rate and mean arterial blood pressure changes were significantly lower in the TF group compared to the CL group. Conclusion: Among patients with difficult airway intubation undergoing general anesthesia, we found the Tube-First intubation approach was quicker and safer compared to the classical intubation technique.

TREATMENT WITH HUMAN UMBILICAL CORD-DERIVED MESENCHYMAL STEM CELLS IN A PIG MODEL OF SEPSIS-INDUCED ACUTE KIDNEY INJURY: EFFECTS ON MICROVASCULAR ENDOTHELIAL CELLS AND TUBULAR CELLS IN THE KIDNEY.

Background: Approximately 50% of patients with sepsis develop acute kidney injury (AKI), which is predictive of poor outcomes, with mortality rates of up to 70%. The endothelium is a major target for treatments aimed at preventing the complications of sepsis. We hypothesized that human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) could attenuate tubular and endothelial injury in a porcine model of sepsis-induced AKI. Methods: Anesthetized pigs were induced to fecal peritonitis, resulting in septic shock, and were randomized to treatment with fluids, vasopressors, and antibiotics (sepsis group; n = 11) or to that same treatment plus infusion of 1 × 10 6 cells/kg of hUC-MSCs (sepsis+MSC group; n = 11). Results: At 24 h after sepsis induction, changes in serum creatinine and mean arterial pressure were comparable between the two groups, as was mortality. However, the sepsis+MSC group showed some significant differences in comparison with the sepsis group: lower fractional excretions of sodium and potassium; greater epithelial sodium channel protein expression; and lower protein expression of the Na-K-2Cl cotransporter and aquaporin 2 in the renal medulla. Expression of P-selectin, thrombomodulin, and vascular endothelial growth factor was significantly lower in the sepsis+MSC group than in the sepsis group, whereas that of Toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB) was lower in the former. Conclusion: Treatment with hUC-MSCs seems to protect endothelial and tubular cells in sepsis-induced AKI, possibly via the TLR4/NF-κB signaling pathway. Therefore, it might be an effective treatment for sepsis-induced AKI.

Predicting Hemodynamic Changes During Intra-Aortic Balloon Pump Support With a Longitudinal Evaluation.

The use of intra-aortic balloon pump (IABP) has decreased in recent years due to negative outcome studies in cardiogenic shock complicating acute myocardial infarction, despite its favorable adverse-event profile. Acute hemodynamic response studies have identified potential super-responders with immediate improvements in cardiac index (CI) in heart failure patients. This single-center retrospective study aimed to predict CI and mean arterial pressure (MAP) changes throughout the entire duration of IABP support. The study analyzed 336 patients who received IABP between 2016 and 2022. Linear mixed-effect regression models were used to predict CI and MAP improvement during IABP support. The results showed that CI and MAP increases during the first days of support, and changes during IABP support varied with time and were associated with baseline parameters. Longitudinal CI change was associated with body surface area, baseline CI, baseline pulmonary artery pulsatility index, baseline need for pressors, and diabetes. Longitudinal MAP change was associated with baseline MAP, baseline heart rate, need for pressors, or inotropes. The study recommends considering these parameters when deciding if IABP is the most appropriate form of support for a specific patient. Further prospective studies are needed to validate the findings.

The Vasopressin Loading for Refractory septic shock (VALOR) study: a prospective observational study

BackgroundVasopressin is a second-line vasoactive agent for refractory septic shock. Vasopressin loading is not generally performed because of the lack of evidence for its effects and safety. However, based on our previous findings, we hypothesized it can predict the responsibility to vasopressin infusion with safety, and prospectively examined it in the present study.MethodsVasopressin loading was performed via the intravenous administration of a bolus of 1 U, followed by its continuous infusion at 1U/h in patients with septic shock treated with ≥ 0.2 μg/kg/min noradrenaline. An arterial pressure wave analysis was conducted, and endocrinological tests were performed immediately prior to vasopressin loading. We classified patients into responders/non-responders based on mean arterial pressure (MAP) changes after vasopressin loading. Based on our previous findings, the lower tertile of MAP changes was selected as the cut-off. The change in the catecholamine index (CAI) after 6 h was assigned as the primary outcome. Digital ischemia, mesenteric ischemia, and myocardial ischemia during the admission period were prospectively and systematically recorded as adverse events.ResultsNinety-two patients were registered during the study period and examined. Sixty-two patients with a MAP change > 22 mmHg were assigned as responders and the others as non-responders. Blood adrenocorticotropic hormone levels were significantly higher in non-responders. Stroke volume variations were higher in responders before loading, while stroke volume and dP/dtmax were higher in responders after loading. Median CAI changes were − 10 in responders and 0 in non-responders, which was significantly lower in the former (p < 0.0001). AUROC of MAP change with vasopressin loading to predict CAI change < 0 after continuous infusion was 0.843 with sensitivity of 0.92 and specificity of 0.77. Ischemia events were observed in 5 cases (5.4%).ConclusionsVasopressin loading may be safely introduced for septic shock. Vasopressin loading may be used to predict responses to its continuous infusion and select appropriate strategies to increase blood pressure.

Hydroxocobalamin Versus Methylene Blue for the Treatment of Vasoplegic Shock Associated With Cardiopulmonary Bypass

To compare changes in vasopressor requirements and hemodynamic responses after hydroxocobalamin or methylene blue administration for vasoplegic shock (VS). Retrospective cohort analysis. Single-center, academic medical center. Cardiothoracic surgery adult patients. Hydroxocobalamin or methylene blue. The primary outcome was a change in vasopressor requirements over the first 24 hours (1, 3, 6, 12, and 24 hours) after hydroxocobalamin or methylene blue initiation. Secondary outcomes included changes in mean arterial pressure (MAP), systemic vascular resistance, and lactate. A total of 120 adult patients who received hydroxocobalamin (n=77) or methylene blue (n=43) were included. Vasopressor requirements at baseline were 0.34 µg/kg/min (95% CI 0.28-0.4) norepinephrine equivalent (NEE) in the hydroxocobalamin group, and 0.59 µg/kg/min (95% CI 0.52-0.66) NEE in the methylene blue group; p < 0.001. Vasopressor requirements decreased significantly at each time point within each group (hour 1 mean [95% CI] NEE, hydroxocobalamin 0.27 µg/kg/min [0.21-0.33]; methylene blue 0.44 µg/kg/min [0.38-0.51]; p < 0.001). The mean MAP at baseline was 65 mmHg (95% CI 63-67) in the hydroxocobalamin group, and 57 mmHg (95% CI 54-59) in the methylene blue group; p < 0.001. The mean MAP increased significantly from baseline at each time point within each group (hour 1 mean [95% CI] hydroxocobalamin 73 mmHg [71-75]; methylene blue 67 mmHg [65-70]; p < 0.001). After adjusting for baseline characteristics, a significantly greater reduction in vasopressor requirements and an increase in MAP were noted in the hydroxocobalamin group compared with the methylene blue group. Hydroxocobalamin was associated with a greater reduction in vasopressor requirements than methylene blue in treating VS associated with cardiopulmonary bypass.

The safety of sodium-glucose co-transporter 2 inhibitors in patients with left ventricular assist device - a single center experience.

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are used increasingly for patients with heart failure or chronic kidney disease to improve cardiac and renal outcomes. The use of these medications in patients with left ventricular assist devices (LVAD) is still limited and lacks evidence regarding the safety profile. In this study, we aimed to report our experience in treating 20 patients, supported by LVAD, with SGLT2 inhibitors. We studied the safety profile of SGLT2 inhibitors (dapagliflozin and empagliflozin) in 20 patients (mean age 64.7 ± 12.2 years, 75% male) supported by LVAD as destination therapy. All patients have diabetes mellitus and were prescribed SGLT2 inhibitors for glycemic control. SGLT2 inhibitors were well tolerated with no major adverse events. Few suction events were reported in three patients without the need for pump speed adjustment. There was no change in mean arterial pressure (71.1 ± 5.6 vs. 70.1 ± 4.8 mmHg, P = 0.063). Modest decline in renal function was observed in six patients within the first weeks after drug initiation. There were no events of diabetic ketoacidosis or limb amputation. SGLT2 inhibitors are safe in patients with LVAD and may potentially improve cardiovascular and renal outcomes in this special population.

A Novel Dual Energy Computed Tomography Score Correlates With Postoperative Outcomes in Chronic Thromboembolic Pulmonary Hypertension.

To compare dual-energy computed tomography (DECT) based qualitative and quantitative parameters in chronic thromboembolic pulmonary hypertension with various postoperative primary and secondary endpoints. This was a retrospective analysis of 64 patients with chronic thromboembolic pulmonary hypertension who underwent DECT. First, a clot score was calculated by assigning the following score: pulmonary trunk-5, each main pulmonary artery-4, each lobar-3, each segmental-2, and subsegmental-1 per lobe; the sum total was then calculated. The perfusion defect (PD) score was calculated by assigning 1 point to each segmental PD. The combined score was calculated by adding clot and PD scores. For quantitative evaluation, we calculated perfused blood volume (PBV) (%) of each lung and the sum of both lungs. Primary endpoints included testing association between combined score and total PBV with change in mean pulmonary arterial pressure ([mPAP], change calculated as preop minus postop values). Secondary endpoints included explorative analysis of the correlation between combined score and PBV with change in preoperative and postoperative pulmonary vascular resistance, change in preoperative 6-minute walk distance (6MWD), and immediate postoperative complications such as reperfusion edema, ECMO placement, stroke, death and mechanical ventilation for more than 48 hours, all within 1 month of surgery. Higher combined scores were associated with larger decreases in mPAP ( =0.27, P =0.036). On average, the decrease in mPAP (pre mPAP-post mPAP) increased by 2.2mmHg (95% CI: -0.6, 5.0) with each 10 unit increase in combined score. The correlation between total PBV and change in mPAP was small and not statistically significant. During an exploratory analysis, higher combined scores were associated with larger increases in 6MWD at 6 months postprocedure ( =0.55, P =0.002). Calculation of DECT-based combined score offers potential in the evaluation of hemodynamic response to surgery. This response can also be objectively quantified.

Assessment of renal sympathetic control using invasive pressure and flow velocity measurements in humans.

Renal sympathetic innervation is important in the control of renal and systemic hemodynamics and is a target for pharmacological and catheter-based therapies. The effect of a physiological sympathetic stimulus using static handgrip exercise on renal hemodynamics and intraglomerular pressure in humans is unknown. We recorded renal arterial pressure and flow velocity in patients with a clinical indication for coronary or peripheral angiography using a sensor-equipped guidewire during baseline, handgrip, rest, and hyperemia following intrarenal dopamine (30 μg/kg). Changes in perfusion pressure were expressed as the change in mean arterial pressure, and changes in flow were expressed as a percentage with respect to baseline. Intraglomerular pressure was estimated using a Windkessel model. A total of 18 patients (61% male and 39% female) with a median age of 57 yr (range: 27-85 yr) with successful measurements were included. During static handgrip, renal arterial pressure increased by 15.2 mmHg (range: 4.2-53.0 mmHg), whereas flow decreased by 11.2%, but with a large variation between individuals (range: -13.4 to 49.8). Intraglomerular pressure increased by 4.2 mmHg (range: -3.9 to 22.1 mmHg). Flow velocity under resting conditions remained stable, with a median of 100.6% (range: 82.3%-114.6%) compared with baseline. During hyperemia, maximal flow was 180% (range: 111%-281%), whereas intraglomerular pressure decreased by 9.6 mmHg (interquartile range: 4.8 to 13.9 mmHg). Changes in renal pressure and flow during handgrip exercise were significantly correlated (ρ = -0.68, P = 0.002). Measurement of renal arterial pressure and flow velocity during handgrip exercise allows the identification of patients with higher and lower sympathetic control of renal perfusion. This suggests that hemodynamic measurements may be useful to assess the response to therapeutic interventions aimed at altering renal sympathetic control.NEW & NOTEWORTHY Renal sympathetic innervation is important in the homeostasis of systemic and renal hemodynamics. We showed that renal arterial pressure significantly increased and that flow decreased during static handgrip exercise using direct renal arterial pressure and flow measurements in humans, but with a large difference between individuals. These findings may be useful for future studies aimed to assess the effect of interventions that influence renal sympathetic control.

Haemodynamic effects of methoxyflurane versus fentanyl and placebo in hypovolaemia: a randomised, double-blind crossover study in healthy volunteers

BackgroundMethoxyflurane is approved for relief of moderate to severe pain in conscious adult trauma patients: it may be self-administrated and is well suited for use in austere environments. Trauma patients may sustain injuries causing occult haemorrhage compromising haemodynamic stability, and it is therefore important to elucidate whether methoxyflurane may adversely affect the haemodynamic response to hypovolaemia. MethodsIn this randomised, double-blinded, placebo-controlled, three-period crossover study, inhaled methoxyflurane 3 ml, i.v. fentanyl 25 μg, and placebo were administered to 15 healthy volunteers exposed to experimental hypovolaemia in the lower body negative pressure model. The primary endpoint was the effect of treatment on changes in cardiac output, while secondary endpoints were changes in stroke volume and mean arterial pressure and time to haemodynamic decompensation during lower body negative pressure. ResultsThere were no statistically significant effects of treatment on the changes in cardiac output, stroke volume, or mean arterial pressure during lower body negative pressure. The time to decompensation was longer for methoxyflurane compared with fentanyl (hazard ratio 1.9; 95% confidence interval 0.4–3.4; P=0.010), whereas there was no significant difference to placebo (hazard ratio −1.3; 95% confidence interval −2.8 to 0.23; P=0.117). ConclusionsThe present study does not indicate that methoxyflurane has significant adverse haemodynamic effects in conscious adults experiencing hypovolaemia. Clinical trial registrationClinicalTrials.gov (NCT04641949) and EudraCT (2019-004144-29) https://www.clinicaltrialsregister.eu/ctr-search/trial/2019-004144-29/NO.

Trending Ability of End-Tidal Capnography Monitoring During Mechanical Ventilation to Track Changes in Arterial Partial Pressure of Carbon Dioxide in Critically Ill Patients With Acute Brain Injury: A Monocenter Retrospective Study.

Changes in arterial partial pressure of carbon dioxide (Pa co2 ) may alter cerebral perfusion in critically ill patients with acute brain injury. Consequently, international guidelines recommend normocapnia in mechanically ventilated patients with acute brain injury. The measurement of end-tidal capnography (Et co2 ) allows its approximation. Our objective was to report the agreement between trends in Et co2 and Pa co2 during mechanical ventilation in patients with acute brain injury. Retrospective monocenter study was conducted for 2 years. Critically ill patients with acute brain injury who required mechanical ventilation with continuous Et co2 monitoring and with 2 or more arterial gas were included. The agreement was evaluated according to the Bland and Altman analysis for repeated measurements with calculation of bias, and upper and lower limits of agreement. The directional concordance rate of changes between Et co2 and Pa co2 was evaluated with a 4-quadrant plot. A polar plot analysis was performed using the Critchley methods. We analyzed the data of 255 patients with a total of 3923 paired ΔEt co2 and ΔPa co2 (9 values per patient in median). Mean bias by Bland and Altman analysis was -8.1 (95 CI, -7.9 to -8.3) mm Hg. The directional concordance rate between Et co2 and Pa co2 was 55.8%. The mean radial bias by polar plot analysis was -4.4° (95% CI, -5.5 to -3.3) with radial limit of agreement (LOA) of ±62.8° with radial LOA 95% CI of ±1.9°. Our results question the performance of trending ability of Et co2 to track changes in Pa co2 in a population of critically ill patients with acute brain injury. Changes in Et co2 largely failed to follow changes in Pa co2 in both direction (ie, low concordance rate) and magnitude (ie, large radial LOA). These results need to be confirmed in prospective studies to minimize the risk of bias.

Randomized Double-Blind Controlled Trial Comparing Safety and Efficacy between Plain Lubricant and Lidocaine Gel during Ambulatory Cystoscopy

Background: Cystoscopy is a basic procedure for urologists to visualize the urethra, the prostate gland, and the urinary bladder. However, ambulatory cystoscopy may be associated with pain and discomfort. Accordingly, varied types and amounts of lubricating gels were studied to relieve these symptoms. Objective: To compare the efficacy and safety between plain lubricant and lidocaine gel during ambulatory cystoscopy. Materials and Methods: The present study was a double-blind randomized controlled trial conducted to evaluate pain during cystoscopy. One hundred patients were randomized into two groups. Group A, 20 mL of 2% lidocaine hydrochloride gel and Group B, 20 mL of plain lubricant gel were instilled into urethra 15 minutes before the procedure. Pain was assessed by an independent data collector using a numerical rating scale (NRS) and visual analog score (VAS). Blood pressure and pulse rate were compared before and after the procedure. Complications were recorded by telephone within several days. Results: The mean NRS of Group A was lower (3.8±2.38) than that of Group B (4.22±2.65) (p=0.407) and the mean VAS of Group A was 2.7±1.36, Group B was 2.66±1.27 (p=0.880). Additionally, the present study found no difference in the change in mean arterial blood pressure (MAP) (Group A 6.69±11.18 mmHg, Group B 4.84±11.45 mmHg, p=0.416) and pulse rate (Group A 6.4±11.9 BPM, Group B 3.73±13.67 BPM, p=0.302). Gross hematuria was seen in one patient (2%) in Group A and three patients (6%) in Group B. Dysuria was equal in both groups. Conclusion: The plain lubricant gel used for cystoscopy without otherwise manipulation has similar safety and efficacy compared to the lidocaine gel. Keywords: Lubricant gel; Ambulatory cystoscopy; Cystoscopy without otherwise manipulation

The role of acid sensing ion channels in the cardiovascular function.

Acid Sensing Ion Channels (ASIC) are proton sensors involved in several physiological and pathophysiological functions including synaptic plasticity, sensory systems and nociception. ASIC channels have been ubiquitously localized in neurons and play a role in their excitability. Information about ASIC channels in cardiomyocyte function is limited. Evidence indicates that ASIC subunits are expressed in both, plasma membrane and intracellular compartments of mammalian cardiomyocytes, suggesting unrevealing functions in the cardiomyocyte physiology. ASIC channels are expressed in neurons of the peripheral nervous system including the nodose and dorsal root ganglia (DRG), both innervating the heart, where they play a dual role as mechanosensors and chemosensors. In baroreceptor neurons from nodose ganglia, mechanosensation is directly associated with ASIC2a channels for detection of changes in arterial pressure. ASIC channels expressed in DRG neurons have several roles in the cardiovascular function. First, ASIC2a/3 channel has been proposed as the molecular sensor of cardiac ischemic pain for its pH range activation, kinetics and the sustained current. Second, ASIC1a seems to have a critical role in ischemia-induced injury. And third, ASIC1a, 2 and 3 are part of the metabolic component of the exercise pressure reflex (EPR). This review consists of a summary of several reports about the role of ASIC channels in the cardiovascular system and its innervation.

The Central Fluid Percussion Brain Injury in a Gyrencephalic Pig Brain: Scalable Diffuse Injury and Tissue Viability for Glial Cell Immunolabeling following Long-Term Refrigerated Storage.

Traumatic brain injury (TBI) affects millions of people annually; however, our knowledge of the diffuse pathologies associated with TBI is limited. As diffuse pathologies, including axonal injury and neuroinflammatory changes, are difficult to visualize in the clinical population, animal models are used. In the current study, we used the central fluid percussion injury (CFPI) model in a micro pig to study the potential scalability of these diffuse pathologies in a gyrencephalic brain of a species with inflammatory systems very similar to humans. We found that both axonal injury and microglia activation within the thalamus and corpus callosum are positively correlated with the weight-normalized pressure pulse, while subtle changes in blood gas and mean arterial blood pressure are not. We also found that the majority of tissue generated up to 10 years previously is viable for immunofluorescent labeling after long-term refrigeration storage. This study indicates that a micro pig CFPI model could allow for specific investigations of various degrees of diffuse pathological burdens following TBI.

Hemodynamic effects of a low versus a high dose of propofol during induction of anesthesia. A randomized trial.

Hypotension is common after anesthesia induction with propofol and is associated with increased morbidity. It is important to examine the effects of the proposed interventions to limit preventable hypotension, as suggested by the reduction in the dose of propofol. Our objective was to investigate whether a high dose of propofol is inferior to a low dose with respect to changes in systolic arterial blood pressure (SAP). This randomized, double-blind, dose-controlled, non-inferiority study included 68 healthy women scheduled for gynecological surgery at the Day Surgery Unit, Haugesund Hospital, Norway. The patients were randomly allocated 1:1 to a low or high dose (1.4 mg/kg total body weight (TBW) versus 2.7 mg/kg TBW of propofol corresponding to maximal effect site concentrations (Ce) of 2.0 μg/mL versus 4.0 μg/mL. The dose of remifentanil was 1.9-2.0 μg/kg TBW, with maximal Ce of 5.0 ng/mL. The patients were observed for 450 s from the start of the infusions. The first 150 s was the sedation period, after which a bolus of propofol and remifentanil was administered. Baseline was defined as 55-5 s before the bolus doses. LiDCOplus was used for invasive beat-to-beat hemodynamic monitoring of changes in SAP, heart rate (HR), cardiac output (CO), stroke volume (SV), and systemic vascular resistance (SVR). A difference of 10 mmHg in the change in SAP was considered to be clinically important. The SAP change difference for low versus high dose was -2.9 mmHg (95% CI -9.0-3.1). The relative changes for low versus high dose were SAP -31% versus -36%, (p < .01); HR -24% versus -20%, (p = .09); SVR -20% versus -31%, (p < .001); SV -16% versus -20%, (p = .04); and CO -35% versus -32%, (p = .33). A high dose of propofol was not inferior to a low dose, and a reduction in the dose of propofol did not result in clinically important attenuation of major hemodynamic changes during induction in healthy women. ClinicalTrials.gov identifier NCT03861364, January 3, 2019.