Noninvasive Systolic Blood Pressure Research Articles

Assessment of hemodynamic parameters and caudal vena cava-to-aorta ratio pre- and post-pericardiocentesis in dogs with cardiac tamponade.

To evaluate haemodynamic parameters and ultrasonographic measurements of the caudal vena-cava-to-aorta ratio at the splenorenal view in canine cardiac tamponade before and 30 minutes after pericardiocentesis. Dogs presenting with cardiac tamponade at two veterinary hospitals were included. Triage examination, noninvasive systolic arterial blood pressure, shock index, venous lactatemia and POCUS results were recorded at admission and 30 minutes after pericardiocentesis. This prospective observational study included 22 dogs, and all had an increased caudal vena-cava-to-aorta ratio. After pericardiocentesis, there were significant changes in vital signs, including a decrease in the median heart rate by 42.1%, a decrease in the median respiratory rate by 40.1%, and an increase in the median rectal temperature from 37.8°C (range: 35.6 to 39.2) to 38.1°C ( 36.1 to 38.7). In regards of hemodynamic parameters, the median systolic arterial pressure increased significantly by 23.2%, the shock index decreased significantly by 52.8%, the median lactate level decreased significantly from 6.1 mmol/L (1.4 to 14.7) to 3.6 mmol/L (1.1 to 13.6), and the median caudal vena-cava-to-aorta ratio decreased significantly by 37.5%, from 1.76 (1.35 to 2.13) to 1.12 (0.91 to 1.51). This study demonstrated an increased caudal vena-cava-to-aorta ratio in dogs with cardiac tamponade and a rapid haemodynamic improvement in dogs with cardiac tamponade within 30 minutes of the pericardiocentesis, resulting in excellent short-term prognosis.

Abstract P445: High Salt Intake Increases Arterial Stiffness Measured by Pulse Wave Velocity in Spontaneously Hypertension Rats

High salt intake represents an important risk factor for the development of hypertension. In this context, the present study aimed to evaluate the impacts of high salt intake on cardiovascular and arterial parameters in spontaneously hypertensive rats (SHR), through pulse wave velocity analysis. Male Wistar rats and SHR were divided into groups drinking water Control (Wistar/C and SHR/C), or Salt (1% NaCl Wistar/S and SHR/S). Rats underwent measurement of systolic blood pressure (SBP) at baseline, 30 and 60 days by plethysmography. After 60 days, rats were catheterized (carotid and femoral arteries) for haemodynamic measurements. The non-invasive SBP was enhanced in SHR after 30 days of salt treatment (SHR/C 200 ± 5.2 vs. SHR/S 218 ± 3.2 mmHg, P<0.01) as at 60 days (SHR/C 206 ± 5.8 vs. SHR/S 225 ± 3.3 mmHg, P<0.05). Arterial stiffness was augmented in SHR rats with 60 days of salt treatment, corresponding to 8% in the pulse wave velocity measurement (SHR/C 6.2 ± 0.2 vs. SHR/S 6.7 ± 0.3 m /s), and 11% in pulse pressure (SHR/C 54 ± 1.3 vs. SHR/S 60 ± 1.7 mmHg). These findings support the hypothesis that high salt intake is related to detrimental haemodynamic and arterial stiffness in SHR and highlights potential novel mechanism enrolled on the pathogenesis and progression of hypertension.

Can a Sacrococcygeal Epidural of 0.25% Bupivacaine Prevent the Activation of the Sympathetic Nervous System during Feline Ovariectomy?

The ovariectomy (OVE) procedure can trigger somatosensory and visceral peritoneal nociception. Sacrococcygeal epidural (ScE) anesthesia may complement or replace systemic analgesia used for feline OVE, reducing opioid consumption and their related undesirable adverse effects and consequently reducing or completely blocking the sympathetic nervous system activation during this procedure. The present study aimed to evaluate the activation of the sympathetic nervous system resulting from adding an ScE injection of bupivacaine 0.25% (0.3 mL kg-1) in feline OVE and identify whether this translates to hemodynamic variables stability. A Parasympathetic Tone Activity (PTA) monitor was applied given that it performs analysis of heart rate variability (HRV) detecting changes in sympathetic and parasympathetic tone, making it a good tool for detecting activation of the sympathetic nervous system during the study. Two groups of animals were evaluated in five perioperative times, namely, the control group (CG) (n = 18) with systemic analgesia alone and the sacrococcygeal epidural group (ScEG) (n = 20) with 0.25% bupivacaine combined with systemic analgesia. Thirty-eight female cats were selected. All animals assigned to CG and ScEG were premedicated with dexmedetomidine (20 μg kg-1 IM) and methadone (0.2 mg kg-1 IM). General anesthesia was induced with propofol IV ad effectum and maintained with isoflurane in 100% oxygen. Heart rate, non-invasive systolic and median blood pressure, respiratory rate, and instantaneous parasympathetic tone activity were recorded. Compared to systemic analgesia alone (CG), sacrococcygeal epidural (ScEG) reduced the rise of common hemodynamic variables but did not prevent sympathetic nervous system activation.

Effects of Medetomidine-Butorphanol and Medetomidine-Buprenorphine on Oxidative Stress and Vital Parameters in Dogs Undergoing Ovariohysterectomy.

Oxidative stress (OS) is caused by an imbalance between the production of oxygen-containing free radicals and their elimination. General anesthesia increases the production of reactive oxygen species (ROS) and therefore causes oxidative stress. Our objective was to determine the effects of medetomidine-butorphanol (MEDBUT) and medetomidine-buprenorphine (MEDBUP) on oxidative stress and cardiorespiratory parameters in dogs undergoing ovariohysterectomy (OHE). Ten healthy female dogs were randomly assigned to two groups: the MEDBUT group (n = 5) received medetomidine and butorphanol, while the MEDBUP group (n = 5) received medetomidine and buprenorphine. OS was evaluated by measuring total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) during five different time points (from the administration of anesthetic drugs to 2 h after surgery). The observed vital cardiorespiratory parameters included heart rate (HR), respiratory rate (fR), noninvasive systolic (SAP) and diastolic (DAP) arterial blood pressures, oxygen saturation (SpO2), end-tidal CO2 (EtCO2), and body temperature (BT). Cardiorespiratory parameters were altered at a significantly greater degree in animals sedated with MEDBUT (p < 0.05). The administration of medetomidine-butorphanol was more likely to increase OS parameters, while medetomidine-buprenorphine showed decreased levels of oxidative stress throughout the study.

Effect of Anesthesia Induction with Midazolam on Hemodynamics in Abdominal Hysterectomy Surgeries

Objective: The primary task of anesthesiology is to control the patient's hemodynamic values, including blood pressure and heart rate, from pre-operative to post-operative. Many drugs are used alone or in combination for induction and maintenance of anesthesia. Various hemodynamic responses may develop to these drugs. In our study, we aimed to compare the effects of midazolam and propofol used alone in intravenous anesthesia induction on hemodynamics in patients undergoing abdominal hysterectomy. Materials and Methods: A total of 60 ASA I-II patients scheduled for abdominal hysterectomy were included in the study. During anesthesia induction, midazolam (0.2 mg/kg) was administered to Group M (n:30) and propofol 1% (2 mg/kg) was administered to Group P (n:30). Noninvasive systolic blood pressure, diastolic blood pressure, mean blood pressure and minute heart rate values were recorded. Results: Systolic blood pressure was significantly lower in group P than in M during intubation, skin incision, extubation and recovery. Conclusion:As a result, anesthesia induction with intravenous 0.2 mg/kg midazolam may cause higher systolic blood pressure values than 2 mg/kg propofol. It should not be overlooked that the hemodynamic response that will occur after the use of midazolam during anesthesia monitoring will vary depending on the anesthetic drugs and doses used together.

A randomized double blind study to evaluate the effect of nebulized dexmedetomidine on the haemodynamic response to laryngoscopy – Intubation and intubation conditions

: A cardiovascular stress response is frequently brought on by direct laryngoscopy and intubation. It is widely known that the sympathetic adrenal stimulation elicited by mechanical stimulation to the upper respiratory tract is what causes the haemodynamic response during laryngoscopy and intubation. The study's goal was to assess the impact of preoperative dexmedetomidine nebulization on the patient's hemodynamic response to laryngoscopy- intubation and the intubation conditions.: The American Society of Anaesthesiologists (ASA) I &amp; II adult patients, of either gender, undergoing elective surgeries requiring tracheal intubation were randomized to receive nebulized dexmedetomidine (Group D) or 0.9% saline (Group P), 30 minutes prior to the induction of anesthesia. This study was conducted in the department of anesthesia and critical care at the Christian Medical College in Ludhiana. Following laryngoscopy, the patient's heart rate and non-invasive systolic and diastolic blood pressure will be monitored for 10 minutes. The intubation conditions were noted during laryngoscopy.Total 100 patients with 50 in each group were included. At the time of laryngoscopy and after the intubation 1 min, 3 min,5 min, 7min and 10 min there were significantly lower trend in increasing HR, SBP, DBP and RPP in dexmedetomidine group versus saline. The intubation score representing conditions for intubation was significantly better in the dexmedetomidine group (P=0.013) than the saline group. There was no significant side effect noted (p=1.000). There was significant reduction in intraoperative analgesic and sedative requirement observed in dexmedetomidine groupOur study concluded that the nebulized dexmedetomidine attenuated haemodynamic response to laryngoscopy- intubation and provided better intubation conditions without significant side effects. We advise using nebulized dexmedetomidine pre-operatively for a surgical procedure requiring general anesthesia in order to reduce the haemodynamic response to intubation and to facilitate intubation conditions without experiencing any severe adverse effects.

Aortic Coarctation Stenting in Adolescents and Adults: A Single-Center Experience.

The aim of this study was to evaluate the short and midterm results of aortic coarctation (AoCo) stenting in an adolescent and adult population. All patients with a AoCo older than 14years treated by stent placement between December 2000 and November 2016 were included in this study. Twenty-eight patients with an invasive peak systolic pressure gradient >20mmHg were identified. Number of redilations, non-invasive systolic blood pressure, peak systolic pressure gradient, antihypertensive medication intake, claudication status and complications were evaluated. Twenty-two covered and 6 uncovered stents were successfully placed. Peak systolic pressure gradient decreased immediately after stenting from a mean of 32 mmHg to 0mmHg (± 7mmHg). Mean AoCo diameter increased from 8 tot 16mm (± 4mm). Peripheral arterial injury was seen in 2 patients (7.1%). The mean follow-up time was 60 ± 49months. Redilation of the stent was required in 4 patients, 2 to accommodate for growth and 2 for restenosis. Six (35%) patients could stop all antihypertensive medication. All claudicants (6/28) became and remained asymptomatic after surgery and during their follow-up. No aneurysms, stent fractures or dissections were noticed. There were 2 stent migrations during the first procedure with only 1 needing additional stent placement. Aortic coarctation stenting is a safe and effective treatment that significantly reduces the peak systolic pressure gradient. Antihypertensive medication can be reduced, and increase of walking distance in claudicants can be obtained. Younger patients may need more frequent reinterventions to accommodate for growth.

P404 MYOCARDIAL WORK EVALUATION IN PATIENTS WITH SEVERE AORTIC STENOSIS UNDERGOING TRANSCATHETER AORTIC VALVE REPLACEMENT

Abstract Background myocardial work (MW) is a novel echocardiographic technique that enables the study of left ventricular performance. It overcomes speckle tracking echocardiography (STE) limitations, dependent on afterload, which is increased in patients with severe aortic stenosis (AS). Aims: To evaluate myocardial performance indexes obtained with MW in patients with AS and indication to percutaneous aortic valve replacement (TAVR) before and after the procedure. Methods patients with severe AS and preserved left ventricular systolic function (LVEF) and indication to TAVR underwent complete echocardiographic evaluation the day before and within two days after the procedure. MW indices were calculated considering noninvasive systolic blood pressure (SBP) and corrected for the mean transvalvular aortic gradient. Results 39 patients (78±6 years, 61.5% women) were enrolled, they presented at baseline preserved LVEF (59.4±8.2%) and reduced global longitudinal strain (GLS) (–16.8±3.3%). Corrected global work index (cGWI) and corrected global constructive work (cGCW) appeared elevated before the procedure, and were significantly reduced within 2 days after TAVR (cGWI –2460.5±839.7 mmHg% vs 1844.4±521.6 mmHg%, p&amp;lt;0.01; cGCW 3061.3 ± 796.0 vs 2277.4 ± 536.5mmHg%, p&amp;lt;0.01). Adjusted global wasted work (cGWW) and adjusted global work efficiency (cGWE) did not change significantly after TAVR (cGWW 262.6±151.8 vs 244.2±129.2 mmHg%, p=0.236; cGWE 90.1±4.5 vs 88.5±5.2%, p=0.079) in the overall population. In the subgroup of patients who had not developed new atrioventricular or intraventricular conduction abnormalities, cGWW also significantly decreased following TAVR (275±152.6 vs 216.3 ± 99.7 mmHg%, p=0.018), with no change in cGWE (89.7±4.8 vs 89.3±5.8%, p=0.838). Conclusions The reduction in cGWI and cGWC values and thus myocardial oxygen consumption in the immediate post–TAVR is attributable to the reduction in afterload. Left ventricular function abnormalities do not totally regress after the procedure, although the lack of reduction in cGWW could be partly due to the development of atrioventricular or intraventricular conduction defects. Further studies are desirable to define a role of MW in prognostic stratification of patients with severe AS.

PS-C08-5: VALIDATE-CKD - PRELIMINARY FINDINGS ON CENTRAL BLOOD PRESSURE DEVICES ACCURACY IN PATIENTS WITH STAGES G4-G5 CHRONIC KIDNEY DISEASE

Objective: Measurement of brachial cuff blood pressure (BP) was designed as a convenient surrogate to the aortic BP, which is the BP that dictates perfusion to target organs. In the general population, brachial cuff systolic BP (SBP) has a somewhat acceptable accuracy towards aortic BP but less is know in populations with marked high arterial stiffness, such as in G4-G5 CKD. Central BP devices were designed to directly estimate the aortic BP through pulse wave analysis to a greater accuracy than brachial cuff BP. The aim of the ongoing VALIDATE-CKD study is to compare the accuracy of brachial and central BP readings towards the intraarterial aortic SBP, in patients with and without Stage G4-G5 CKD. Design and method: In patients with and without Stage G4-G5 CKD (eGFR &lt; 30 ml/min/1.73m2) undergoing non-urgent coronary angiograms, invasive aortic and non-invasive (WatchBP and Mobil-o-graph devices) BPs were measured simultaneously following the ARTERY Society protocol. Accuracy was defined by the mean difference (± SD) between the aortic SBP and the corresponding non-invasive SBP. Results: To date, 8 individuals with Stage G4-G5 CKD and 26 control subjects are enrolled. The following table presents clinical characteristics and non-invasive BPs accuracies in patients with and without Stage G4-G5 CKD. Conclusion: These preliminary results indicate that brachial SBP significantly underestimates aortic SBP in patients with Stage G4-5 CKD as compared to control subject. Furthermore, central BP devices provide a highly accurate estimation of aortic SBP in this population. The ongoing VALIDATE-CKD study may support that the use of central BP devices could be beneficial for the management of patients with advanced CKD.

Subject-wise model generalization through pooling and patching for regression: Application on non-invasive systolic blood pressure estimation

Background:Subject-wise modeling using machine learning is useful in many applications requiring low error and complexity, such as wearable medical devices. However, regression accuracy depends highly on the data available to train the model and the model’s generalization ability. Adversely, the prediction error may increase severely if unknown data patterns test the model; such a model is known to be overfitted. In medicine-related applications, such as Non-Invasive Blood Pressure (NIBP) estimation, the high error renders the estimation model useless and dangerous. Methods:This paper presents a novel algorithm to handle overfitting by editing the training data to achieve generalization for subject-wise models. The pooling and patching (PaP) algorithms use a relatively short record segment of a subject as a Key-Segment (KS) to search through a larger dataset for similar subjects. Then samples taken from the matched subjects’ pool records are used to patch the original subject’s KS. Due to the significance of systolic blood pressure (SBP) and the complexity of its variability, non-invasive estimation of SBP from electrocardiography (ECG) and photoplethysmography (PPG) is introduced as an application to assess the algorithm. The study was performed on 2051 subjects with a wide range of age, height, weight, length, and health status. The subjects’ records were taken from a large public dataset, VitalDB, which is acquired from subjects undergoing different surgeries. Finally, all the results are obtained without using other model generalization techniques. Results:The generalization effect of the proposed algorithm, PaP, significantly outperformed cross-validation, which is widely used in regression model generalization. Moreover, the testing results show that a KS of 200 to 2000 samples is sufficient for providing high accuracy for much longer testing data of about 12000 to 24000 samples long, which is less than %10 of the record length on average. Furthermore, compared to other works based on the same dataset, PaP provides a significantly lower mean error of -0.75 ± 5.51 mmHg, with a small training data portion of 15% over 2051 subjects.

Outcome of Low-Dose 0.5% Levobupivacaine (Plain) And Low-Dose 0.5% Bupivacaine (Heavy) Combined with Fentanyl in Spinal Anaesthesia For Transurethral Resection of Prostate: A Comparative Study

Background: Spinal anaesthesia is widely used for transurethral resections of prostate (TURP) because it allows early recognition of symptoms caused by over hydration, TURP syndrome, and bladder perforation. Patients undergoing TURP surgery have coexisting pulmonary or cardiac disease. Objective: To evaluate the outcome of the two anaesthetic agents – levobupivacaine and bupivacaine in TURP surgery when they are combined with fentanyl. Method: Total eighty patients were selected by inclusion and exclusion criteria, and then the selected patients were randomly divided into 2 groups (40 in each). levobupivacaine group (1) was received intrathecal 0.5% levobupivacaine 5mg (1 ml) + 25 micro gram fentanyl (0.5ml) and in bupivacaine group (2) was received intrathecal 0.5% bupivacaine heavy 5 mg(1ml) +25 micro gram fentanyl(0.5ml) slowly @1ml/10sec. Heart rate, noninvasive systolic, diastolic and mean arterial blood pressures and oxygen saturation (SpO2) were recorded immediately before intrathecal injection and every 3 min for 15 min after intrathecal injection and there after every 5 minutes upto 40 minutes and at the end of surgery. Results: All the haemodynamic variables except heart rate were almost statistically matched. Half of levobupivacaine group and 30% of the bupivacaine group achieved a sensory block up to the level of T10. Sixty percent of the levobupivacaine and 15% of the bupivacaine group at the beginning of the surgery had modified Bromage score ‘1’. None of the levobuppivacaine and 15% of the bupivacaine groups had a Bromage score ’3’. The recovery from motor block was significantly earlier in the levobupivacaine group compared to that in the bupivacaine group. Over half (55%) of the former group exhibited complete recovery at the end of surgery as opposed to only 20% of the latter group. Conclusion: For TURP surgery, a low dose of levobupivacaine with fentanyl can provide an adequate sensory blockade and can be used as a good alternative to bupivacaine. Sir Salimullah Med Coll J 2022; 30: 115-122

Anti-Hypertensive Activity of Some Selected Unani Formulations: An Evidence-Based Approach for Verification of Traditional Unani Claims Using LC-MS/MS for the Evaluation of Clinically Relevant Blood Parameters in Laboratory Rats.

Background: Systemic arterial hypertension, which is associated with an increased risk of cardiovascular disease(CVD), is the most significant modifiable risk factor for mortality and morbidity worldwide. WHO has recognized Unanipathy as an alternate system of medicine. The aim of the present study is to investigate the anti-hypertensive activity of some selected unani formulations using L-NAME model. Method: Group I or hypertensive control group: L-NAME administered for 7 days and left for the next 7 days; Group II or KASgroup: L-NAME administered (i.p) for 7 days and L-NAME + KAS (1000 mg/kg b.w) for the next 7 days; Group III or DMM group: L-NAME administered (i.p) for 7 days and L-NAME + DMM (2000 mg/kg b.w) for the next 7 days; Group IV or MSR group: L-NAME administered (i.p) for 7 days and L-NAME + MSR (300 mg/kg b.w) for the next 7 days; Group V or HJ group: L-NAME administered (i.p) for 7 days and L-NAME + HJ (113 mg/kg b.w) for the next 7 days; Group VI or KGS group: L-NAME administered (i.p) for 7 days and L-NAME +KGS (2000 mg/kg b.w) for the next 7 days. Non-invasive systolic blood pressure and RR-interval (ECG) was measured. Plasma was investigated forsodium, potassium, nitrite, ANP, adrenaline, noradrenaline and aldosterone on day 0, 7 and 14 using LC-MS/MS. Result: Treatment showed a non-significant lowreduction in SBP (systolic blood pressure) of KAS, MSR and HJ while that of DMM was quite significant (p < 0.05), but in the case of KGS, SBP increased. DMM on day 14 significantly (p < 0.05) reduced plasma nitrite while no significant plasma Na+ was noted. In the case of both DMM and KGS, potassium increased significantly (p < 0.05) on day 14. No significant changes in plasma ANP and aldosterone was observed against DMM and KGS while blood levels of adrenaline and noradrenaline significantly (p < 0.05) changed. No significant change in body weight was found. Conclusions: L-NAME KAS, MSR and HJ showed no change in SBP while DMM showed a significant reduction in SBP with decreased plasma nitrite. Probably, DMM may have anti-hypertensive activity mediated through NO inhibition while KGS may involve central sympathomimetic action.

Myocardial work evaluation in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation

Abstract Funding Acknowledgements Type of funding sources: None. Background myocardial work (MW) is a novel echocardiographic technique which assesses left ventricular (LV) performance through LV pressure-strain loops. MW corrects speckle tracking echocardiography (STE)-derived parameters for afterload using non-invasive systolic blood pressure (SBP) as a surrogate for LV systolic pressure. In patients with severe aortic stenosis (AS), the corrected MW (cMW) has been proposed, consisting in adding the mean aortic gradient in SBP. This method revealed to be feasible and reliable, demonstrating good correlation with invasively measured LV systolic pressure. Purpose to evaluate myocardial performance of patients with severe AS, before and after transcatheter aortic valve implantation (TAVI), by MW indices. Methods patients with severe AS undergoing TAVI were included. Transthoracic, standard echocardiography and STE were performed the day before the procedure and within 2 days after. MW was calculated by combining STE-derived indices with non-invasively estimated LV systolic pressure. Results 30 patients (79 ± 5 years old, 56% females) with severe AS (mean gradient 47 ± 14 mmHg, aortic valve area 0.6 ± 0.1 cm2), and eligible for TAVI were enrolled. Baseline global longitudinal strain was impaired (GLS -15 ± 4%), in presence of normal LV ejection fraction (LVEF 57 ± 10%). Corrected global work index and global constructive work were preserved at baseline and markedly decreased after TAVI (cGWI 2322 ± 791 vs 1710 ± 505 mmHg%, p = 0.001; cGCW 2774 ± 803 vs 2083 ± 536 mmHg%, p = 0.0007). Corrected global wasted work and global work efficiency were higher than reference values existing in literature, and no significant changes were observed after TAVI (cGWW 276 ± 174 vs 277 ± 165 mmHg%, p = 0.974; cGWE 89 ± 5 vs 87 ± 5%, p = 0.177). A significant inverse correlation was found between baseline cGWI and left atrial volume index (r=-0.5, p = 0.03). Conclusions patients with severe aortic stenosis and preserved LVEF show a good LV performance before and after TAVI, with a significant decrease in MW indices after TAVI, because of the reduced afterload due to AS treatment. The negative correlation between left atrial volume and cGWI may reflect the extent of myocardial damage in AS. However, further studies with larger sample size and appropriate follow-up are needed to evaluate the role of MW in prognosis and risk stratification of this subset of patients.

Comparison of the effects of target-controlled infusion-remifentanil/midazolam and manual fentanyl/midazolam administration on patient parameters in dental procedures.

BackgroundModerate sedation is an integral part of dental care delivery. Target-controlled infusion (TCI) has the potential to improve patient safety and outcome. We compared the effects of using TCI to administer remifentanil/manual bolus midazolam with manual bolus fentanyl/midazolam administration on patient safety parameters, drug administration times, and patient recovery times.MethodsIn this retrospective chart review, records of patients who underwent moderate intravenous sedation over 12 months in a private dental clinic were assessed. Patient indicators (pre-, intra-, and post-procedure noninvasive systolic and diastolic blood pressure, respiration, and heart rate) were compared using independent t-test analysis. Patient recovery time, procedure length, and midazolam dosage required were also compared between the two groups.ResultsEighty-five patient charts were included in the final analysis: 47 received TCI-remifentanil/midazolam sedation, and 38 received manual fentanyl/midazolam sedation. Among the physiological parameters, diastolic blood pressure showed slightly higher changes in the fentanyl group (P = 0.049), respiratory rate changes showed higher changes in the fentanyl group (P = 0.032), and the average EtCO2 was slightly higher in the remifentanil group (P = 0.041). There was no significant difference in the minimum SpO2 levels and average procedure length between the fentanyl and remifentanil TCI pump groups (P > 0.05). However, a significant difference was observed in the time required for discharge from the chair (P = 0.048), indicating that patients who received remifentanil required less time for discharge from the chair than those who received fentanyl. The dosage of midazolam used in the fentanyl group was 0.487 mg more than that in the remifentanil group; however, the difference was not significant (P > 0.05).ConclusionThe combination of TCI administered remifentanil combined with manual administered midazolam has the potential to shorten the recovery time and reduce respiration rate changes when compared to manual administration of fentanyl/midazolam. This is possibly due to either the lower midazolam dosage required with TCI remifentanil administration or achieving a stable, steady-state low dose remifentanil concentration for the duration of the procedure.

227 Myocardial work evaluation in severe aortic stenosis undergoing transcatheter aortic valve implantation

Abstract Aims Myocardial work (MW) is a novel echocardiographic technique which assesses left ventricular (LV) performance through LV pressure-strain loops. MW corrects speckle tracking echocardiography (STE)-derived parameters for afterload using non-invasive systolic blood pressure (SBP) as a surrogate for LV systolic pressure. In patients with severe aortic stenosis (AS), the corrected MW (cMW) has been proposed, consisting in adding the mean aortic gradient in SBP. This method revealed to be feasible and reliable, demonstrating good correlation with invasively measured LV systolic pressure. To evaluate myocardial performance of patients with severe AS, before and after transcatheter aortic valve implantation (TAVI), by MW indices. Methods patients with severe AS undergoing TAVI were included. Transthoracic, standard echocardiography and STE were performed the day before the procedure and within 2 days after. MW was calculated by combining STE-derived indices with non-invasively estimated LV systolic pressure. Results 30 patients (79±5 years old, 56% females) with severe AS (mean gradient 47±14 mmHg, aortic valve area 0.6±0.1 cm2), and eligible for TAVI were enrolled. Baseline global longitudinal strain was impaired (GLS −15±4%), in presence of normal LV ejection fraction (LVEF 57±10%). Corrected global work index and global constructive work were preserved at baseline and markedly decreased after TAVI (cGWI 2322±791 vs. 1710±505 mmHg%, P=0.001; cGCW 2774±803 vs. 2083±536 mmHg%, P=0.0007). Corrected global wasted work and global work efficiency were respectively higher and lower than reference values existing in literature, and no significant changes were observed after TAVI (cGWW 276±174 vs. 277±165 mmHg%, P=0.974; cGWE 89±5 vs. 87±5%, P=0.177). A significant inverse correlation was found between baseline cGWI and left atrial volume index (r = −0.5, P=0.03). Conclusions Patients with severe aortic stenosis and preserved LVEF show a good LV performance before and after TAVI, with a significant decrease in MW indices after TAVI, because of the reduced afterload due to AS treatment. The negative correlation between left atrial volume and cGWI may reflect the extent of myocardial damage in AS. However, further studies with larger sample size and appropriate follow-up are needed to evaluate the role of MW in prognosis and risk stratification of this subset of patients.

Blood Pressure in Critically Ill Children: Exploratory Analyses of Concurrent Invasive and Noninvasive Measurements.

Differences and biases between directly measured intra-arterial blood pressure and intermittingly measured noninvasive blood pressure using an oscillometric cuff method have been reported in adults and children. At the bedside, clinicians are required to assign a confidence to a specific blood pressure measurement before acting upon it, and this is challenging when there is discordance between measurement techniques. We hypothesized that big data could define and quantify the relationship between noninvasive blood pressure and intra-arterial blood pressure measurements and how they can be influenced by patient characteristics, thereby aiding bedside decision-making. A retrospective analysis of cuff blood pressure readings with associated concurrent invasive arterial blood pressure measurements (452,195 noninvasive blood pressure measurements). Critical care unit at The Hospital for Sick Children, Toronto. Six-thousand two-hundred ninety-seven patients less than or equal to 18 years old, hospitalized in a critical care unit with an indwelling arterial line. None. Two-dimensional distributions of intra-arterial blood pressure and noninvasive blood pressure were generated and the conditional distributions of intra-arterial blood pressure examined as a function of the noninvasive systolic, diastolic, or mean blood pressure. Modification of these distributions according to age and gender were examined using a multilevel mixed-effects model. For any given combination of patient age and noninvasive blood pressure, the expected distribution of intra-arterial blood pressure readings exhibited marked variability at the population level and a bias that significantly depended on the noninvasive blood pressure value and age. We developed an online tool that allows exploration of the relationship between noninvasive blood pressure and intra-arterial blood pressure and the conditional probability distributions according to age. A large physiologic dataset provides clinically applicable insights into the relationship between noninvasive blood pressure and intra-arterial blood pressure measurements that can help guide decision-making at the patient bedside.

Left ventricular myocardial work in patients with high gradient severe symptomatic aortic stenosis

Abstract Background Left ventricular myocardial work (LVMW) is a novel method to evaluated left ventricular (LV) function using pressure-strain loops. It might correct global longitudinal strain (GLS) for afterload, being eventually useful to assess whether GLS reduction is due to reduced contractility (reflected as reduced myocardial work) or increased afterload (reflected as increased myocardial work). Aim To describe indices of LVMW in a group of patients with severe symptomatic aortic stenosis (AS). Methods We prospectively studied 104 consecutive patients (age: 71 years [IQR 66.5–75.5] years, 51% men) with severe symptomatic high gradient AS: mean transaortic pressure gradient: 56.5mmHg [IQR 46.8–67.8]; aortic valve area: 0.73cm2 [IQR 0.61–0.88]; indexed stroke volume: 47.7±1.3 mL/m2 (11 patients with low-flow AS), preserved LV ejection fraction (EV) (LVEF: 56.0% [51.0–61.3]; GLS: −14.5% [IQR −16.1 to −10.6]), with no previous coronary artery disease and no history of cardiomyopathy. Beyond complete transthoracic echocardiography, all patients underwent cardiac magnetic resonance for LV myocardium tissue characterization. As proposed for AS, LV systolic pressure was corrected adding the mean transaortic pressure gradient to non-invasive systolic blood pressure cuff measurement in the echocardiographic algorithm. Four LVMW indices were collected in 83 patients (patients excluded for atrial fibrillation, left bundle branch block or absence of non-invasive blood pressure registration) and correlated to LV function indexes, LV hypertrophy and remodeling, myocardial tissue characterization, BNP and troponin levels (Pearson or Spearman correlation). These same indexes were compared in patients with LV ejection fraction (EF) below and above 50%, normal and reduced flow and presence of replacement fibrosis. Results Global constructive work (GCW) (2658.6±76.4mmHg%), global myocardial work (GMW) (2218.7±74.9mmHg%) and global wasted work (GWE) (262.0mmHg% [198.8–339.5]) were high above normal with concomitant lower work efficiency (WE) (88.0% [83.2–91.8]. Weak correlations were found between LVMW indexes and parameters describing aortic valve severity, flow and LV function (table). Except for significant differences of LVMI in patients with reduced LV ejection fraction (GCW 2770.3±687.4 vs 2056.0±380.7mmHg%, p=0,014 and GMW 2362.5±657.9 vs 1621.3±319.9, p=0,021 in patients with LV EF&amp;gt;50% vs. LV EF&amp;lt;50%, respectively) work indexes were neither significantly different in low-flow patients nor in those with myocardial late gadolinium enhancement. Conclusions Global constructive and myocardial work are increased in these patients with severe aortic stenosis. This might reflect an increased afterload predominance rather than a LV functional impairment, particularly relevant in this group of patients with exclusive high gradient disease and preserved LVEF. Funding Acknowledgement Type of funding sources: None. Correlations between LVMI – LV function

Perioperative Hemodynamic Monitoring: An Overview of Current Methods.

Perioperative hemodynamic monitoring is an essential part of anesthetic care. In this review, we aim to give an overview of methods currently used in the clinical routine and experimental methods under development. The technical aspects of the mentioned methods are discussed briefly. This review includes methods to monitor blood pressures, for example, arterial pressure, mean systemic filling pressure and central venous pressure, and volumes, for example, global end-diastolic volume (GEDV) and extravascular lung water. In addition, monitoring blood flow (cardiac output) and fluid responsiveness (preload) will be discussed.

Long-term administration of prednisolone: Effects on the myocardial tissue of healthy beagle dogs.

This study aimed to assess the structural and functional effects of long-term hyperglucocorticoidemia on canine myocardium and compare these parameters with histopathological changes. Twelve healthy male beagle dogs were enrolled and assigned to the high-dose prednisolone (P; n=6) and control (C; n=6) groups. The P group was treated with 2 mg/kg of prednisolone BID for 84 days. Clinical parameters were measured using echocardiography and non-invasive systolic blood pressure (SBP) measured before the initiation of synthetic corticosteroids and at 7, 28, 56, and 84 days after the start of medication. For histological evaluation, cardiovascular tissue was harvested from dogs in groups P (at the end of the medication period) and C (scheduled to be euthanized for unrelated reasons). In the P group, clinical changes including thickening of the left ventricular free wall (LVFW) and interventricular septum (IVS), decreased left ventricular (LV) diastolic function, and increased SBP were observed after the start of medication. During histological evaluation, fibrosis was observed in the LVFW and IVS in the P group. Furthermore, decreased glucocorticoid receptor (GCR) levels were observed in the LVFW, right ventricular free wall (RVFW), and IVS and increased mineralocorticoid receptor (MCR) levels were observed in the LVFW and RVFW in the P group compared with those in the C group. In conclusion, fibrosis may cause LV structural and functional abnormalities in dogs with hyperadrenocorticism. Furthermore, GCR downregulation and upregulated MCR might influence the myocardial fibrosis.

Non-invasive cardiovascular assessment of pregnancy in healthy female cats

IntroductionThe aim of this study was to evaluate cardiac morphology, indices of systolic and diastolic function, systolic blood pressure (SBP), and uterine artery resistance index (RI) during normal feline pregnancy. Animals; Materials and MethodsTwenty domestic short-hair pregnant queens, weighing 2.4–3.9 kg. Animals were assessed by two-dimensional, M-mode, and Doppler echocardiography, non-invasive SBP measurement, and uterine Doppler ultrasound every 10 days from mating to parturition. ResultsInterventricular septal thickness at end-diastole and end-systole, left ventricular internal dimension at end-diastole, left ventricular free wall thickness at end-diastole and end-systole, fractional shortening, stroke volume, cardiac output (CO), heart rate, and peak velocities of early and late diastolic transmitral flow increased during the second half of gestation, while SBP and RI decreased during the same period (p < 0.01). Discussion and ConclusionsCardiac structure and function varied during normal pregnancy in these queens. Eccentric hypertrophy, increased indices of systolic function, and increased measurements of CO seem to be the consequences of the hemodynamic modifications occurring during pregnancy. The assessment of maternal cardiovascular function may prove a useful screening tool to detect pregnancy complications in feline species.