Magnesium sulphate within multimodal analgesia, pre-emptive, or preventive analgesia

Background Magnesium (Mg) is a non-competitive N-methyl d-aspartate receptor antagonist with antinociceptive effects. Multimodal therapy is the optimal strategy for perioperative pain control to minimize the need for opioids. Inflammation caused by tissue trauma or direct nerve injury is responsible for the perioperative pain. The concept of “pre-emptive” analgesia, analgesic strategies administered prior to the stimulus, can modify the peripheral and central nervous system processing of noxious stimuli, thereby reducing central sensitization, hyperalgesia, and allodynia remains controversial. A more encompassing approach to the reduction of postoperative pain is the concept of “preventive” analgesia. The purpose of the study is to detect the proper use of MgSO4 as an analgesic being a non-competitive N-methyl d-aspartate (NMDA). Results There is no statistically significant difference in the haemodynamic parameters, intraoperative (33% vs 20%) and postoperative requirement for analgesics 6.6% vs 10% among groups I and II, respectively. There is no significant difference in the numerical analogue scale, where 16 vs 17 patients with no pain, 12 vs 10 with mild pain, and 2 vs 3 with moderate pain in groups I and II, respectively. Conclusion The use of MgSO4 in a bolus with or without infusion is comparable in the control of intraoperative and postoperative pain.

Robotics and the Airway Management

Background: Maternal hypotension due to spinal anaesthesia in caesarean section is commonly seen. Alongwith fluid loading, phenylephrine is used to manage the hypotension. However, this drug is associated with cardiovascular side effects. Methods: This is a prospective double blinded study which was conducted on 100 term parturients scheduled from elective caesarean section under spinal anaesthesia, randomly assigned into two groups. After spinal anaesthesia patients of group N and P were treated with norepinephrine (5mcg) and phenylephrine (50mcg) respectively as an IV bolus for hypotension. Blood pressure, heart rate, number of bolus doses given, and neonatal APGAR score was noted. Results: Patients of both groups were comparable with respect to haemodynamic parameters (HR, SBP, DBP, AND MAP). Incidence of bradycardia was higher in group P (22%, n=11) compared to group N (14%, n=7). Neonatal APGAR scores at different time intervals were similar in both groups. Conclusion: Intermittent boluses of norepinephrine were effective in the treatment of spinal anaesthesia induced hypotension during caesarean section and can be considered as an alternative to phenylephrine.

63 Peripheral endothelial function in patients affected by pulmonary hypertension. Relationship between endothelial function, haemodynamic parameters, and therapy response

Aims Pulmonary hypertension (PH) is defined as a mean pulmonary arterial pressure (mPAP) of 25 mmHg or greater at rest, confirmed by right heart catheterization (RHC). The World Health Organization has classified PH into five clinical subgroups. Pulmonary arterial hypertension (PAH) (group 1) is characterized by loss and obstructive remodelling of the pulmonary vascular bed. These patients are characterized haemodynamically by the presence of precapillary PH, defined as an mPAP of 25 mm Hg or greater, pulmonary artery wedge pressure (PAWP) of 15 mm Hg or less, and pulmonary vascular resistance (PVR) of three Wood units (WU) or greater. Pulmonary hypertension due to left-sided heart disease (LHD) (PH-LHD) (group 2) occurs in HF. Patients with PH-LHD usually have isolated postcapillary PH (PAWP >15 mm Hg and PVR <3 WU), although some of them have combined postcapillary and precapillary PH (PAWP >15 mm Hg and PVR ≥3 WU). PH due to chronic lung disease (CLD) (PH-CLD) and/or hypoxia (group 3) can occur in many lung diseases. These patients have precapillary PH. Chronic thromboembolic PH (CTEPH) (group 4) is characterized by obstruction of the pulmonary vasculature by organized thromboembolic material and vascular remodelling, resulting from prior pulmonary embolism. Patients with unclear and/or multifactorial mechanisms are listed as group 5. Specific pulmonary vasodilators are approved only in PAH patients. While research was predominantly focused on pulmonary vasculature, little is known about the peripheral endothelial damage in different vascular beds in PH patients. To evaluate the relationship between the peripheral endothelial function and the haemodynamic parameters, in order to provide a non-invasive method for the indirect evaluation of mean pulmonary pressure and vascular resistance, to predict if the PH is a precapillary or postcapillary, to select more accurately the patients who should undergo RHC. Moreover, we investigate if there is a possible correlation between endothelial dysfunction and response to specific PH therapies. Methods and results Patients with suspected PH, based on symptoms, medical history, and clinics will undergo physical examination, ECG, echocardiography, and RHC. In all patients, endothelial function was assessed by FMD. Medical history, heart rate, systolic blood pressure, body mass index, WHO functional class, and medications were recorded. All patients underwent blood analysis, erythrocyte sedimentation rate (ERS), high sensitivity C-reactive protein (CRP), and NT-proBNP levels were assayed. Increased peripheral endothelial dysfunction in patients with precapillary PH, with a linear correlation between endothelium dysfunction and increased PVR at the right catheterization. To differentiate pre and post capillary PH forms by cut-off values of the FMD. The degree of endothelial dysfunction could be a marker of therapy response. Sequential combination therapy in the pre-capillary PH forms could be the one with a worst endothelial response than up-front combination therapy.

Computational analysis of aortic haemodynamics in the presence of ascending aortic aneurysm

BACKGROUND: The usefulness of numerical modelling of a patient’s cardiovascular system is growing in clinical treatment. Understanding blood flow mechanics can be crucial in identifying connections between haemodynamic factors and aortic wall pathologies. OBJECTIVE: This work investigates the haemodynamic parameters of an ascending aorta and ascending aortic aneurysm in humans. METHODS: Two aortic models were constructed from medical images using the SimVascular software. FEM blood flow modelling of cardiac cycle was performed using CFD and CMM-FSI at different vascular wall parameters. RESULTS: The results showed that highest blood velocity was 1.18 m/s in aorta with the aneurysm and 1.9 m/s in healthy aorta model. The largest displacements ware in the aorta with the aneurysm (0.73 mm). In the aorta with the aneurysm, time averaged WSS values throughout the artery range from 0 Pa to 1 Pa. In the healthy aorta, distribution of WSS values changes from 0.3 Pa to 0.6 Pa. CONCLUSIONS: In the case of an ascending aortic aneurysm, the maximum blood velocity was found to be 1.6 times lower than in the healthy aorta. The aneurysm-based model demonstrates a 45% greater wall displacement, while the oscillatory shear index decreased by 30% compared to healthy aortic results.

Non-Invasive Continuous Measurement of Haemodynamic Parameters—Clinical Utility

The evaluation and monitoring of patients’ haemodynamic parameters are essential in everyday clinical practice. The application of continuous, non-invasive measurement methods is a relatively recent solution. CNAP, ClearSight and many other technologies have been introduced to the market. The use of these techniques for assessing patient eligibility before cardiac procedures, as well as for intraoperative monitoring is currently being widely investigated. Their numerous advantages, including the simplicity of application, time- and cost-effectiveness, and the limited risk of infection, could enforce their further development and potential utility. However, some limitations and contradictions should also be discussed. The aim of this paper is to briefly describe the new findings, give practical examples of the clinical utility of these methods, compare them with invasive techniques, and review the literature on this subject.

Pulse Wave Velocity, Central Haemodynamic Parameters, and Markers of Kidney Function in Children

<b><i>Objectives:</i></b> Chronic kidney disease (CKD) is a well-established risk factor for cardiovascular diseases. Studies in adults have demonstrated the association between mildly decreased kidney function or even normal values of markers of kidney function to pulse wave velocity (PWV), a measure of arterial stiffness and a predictor of cardiovascular events. Our study aimed to evaluate associations between markers of CKD, PWV, and central haemodynamic parameters in children and adolescents at risk of subclinical kidney damage. <b><i>Methods:</i></b> 182 children and adolescents with hypertension, obesity, or hypercholesterolaemia (risk factors for subclinical kidney damage) were included in the study. The subjects were subdivided into 4 groups comprising children and adolescents with hypertension (group 1), obesity (group 2), hypercholesterolaemia (group 3), and a group with a combination of risk factors, such as obesity-related hypertension and metabolic syndrome (group 4). The study groups were compared to a group of healthy controls (group 5). PWV was measured by applanation tonometry (SphygmoCor, SCOR-Vx, Sydney, NSW, Australia) and laboratory parameters (serum creatinine, serum cystatin C, and microalbuminuria) were collected. <b><i>Results:</i></b> Pearson’s correlation coefficient demonstrated a statistically significant correlation between PWV and serum creatinine in group of all subjects (<i>r</i> = 0.220, <i>p</i> = 0.002). Further subdivision showed the correlation was significant in group 4 (<i>r</i> = 0.370, <i>p</i> = 0.002). In group 2 a correlation between PWV and cystatin C was found (<i>r</i> = −0.535, <i>p</i> = 0.009). In multiple regression analysis of all subjects with PWV as the dependent variable, age and diastolic blood pressure were statistically significant. Correlations between markers of kidney function and central haemodynamic parameters also showed significant correlations between serum creatinine and heart rate (HR) (<i>r</i> = −0.476, <i>p</i> &#x3c; 0.001) as well as associated parameters (augmentation index, standardized at HR 75/min, ejection duration, and subendocardial viability ratio). <b><i>Conclusions:</i></b> Our study demonstrated a correlation between serum creatinine and PWV in children with combined risk factors for atherosclerosis and probable subclinical kidney damage. Further prospective research is needed to confirm the findings, and thus the preventive role of PWV determination in paediatric nephrology.

Anaesthetic protocol for paediatric glaucoma examinations: the prospective EyeBIS Study protocol

IntroductionNeonates and young infants with diagnosed or highly suspected glaucoma require an examination under anaesthesia to achieve accurate intraocular pressure (IOP) measurements, since crying or squinting of the eyes may increase IOP and lead to falsely high values. IOP considerably depends on perioperative variables such as haemodynamic factors, anaesthetics, depth of anaesthesia and airway management. The aim of this paper is to report the design and baseline characteristics of EyeBIS, which is a study to develop a standardised anaesthetic protocol for the measurement of IOP under anaesthesia in childhood glaucoma, by investigating the link between the magnitude of IOP and depth of anaesthesia.Methods and analysisThis is a single-centre, prospective cohort study in 100 children with diagnosed or highly suspected glaucoma all undergoing ophthalmological examination under general anaesthesia. 20 children, who undergo general anaesthesia for other reasons, are included as controls. The primary outcome measure is the establishment of a standardised anaesthetic protocol for IOP measurement in childhood glaucoma by assessing the relationship between IOP and depth of anaesthesia (calculated as an electroencephalography variable, the bispectral index), with special emphasis on airway management and haemodynamic parameters. The dependence of IOP under anaesthesia on airway management and haemodynamic parameters will be described, using a mixed linear model. Restricting the model to patients with healthy eyes will allow to determine a 95% reference region, in which 95% of the measurement values of patients with healthy eyes can be expected.Ethics and disseminationThe study has been approved by the local ethics committee of the Medical Association of Rhineland-Palatine (Ethik-Kommisssion der Landesaerztekammer Rheinland-Pfalz), Germany (approval number: 2019-14207). This work will be disseminated by publication of peer-reviewed manuscripts, presentation in abstract form at national and international scientific meetings and data sharing with other investigators.Trial registration numberClinicalTrials.gov Registry (NCT03972852).

Adverse effects of COVID-protective face-masks and wearing durations onto respiratory-haemodynamic physiology and exhaled breath constituents

While protecting against the coronavirus transmission, face-masks may have adverse effects on respiratory-haemodynamic parameters. We investigated immediate and progressive effects of FFP2 and surgical masks on exhaled breath constituents and physiological attributes in 30 healthy volunteers at rest. We continuously monitored exhaled breath profiles in the mask space in elderly (age: 60–80 years) and adults (age: 20–60 years) over a period of 30 min by high-resolution real-time mass-spectrometry (PTR-ToF-MS). Peripheral oxygen saturation, respiratory- and haemodynamic parameters were measured (non-invasively) continuously in parallel. Profound and consistent decrease in SpO2 and increase in pET-CO2 indicates ascending deoxygenation and inadequate ventilation in subjects. Cardiac output and MAP changed as secondary. Exhalation of blood-borne volatile metabolites mirrored behaviour of cardiac output, MAP, SpO2, respiratory rate and pET-CO2. FFP2 masks affected more pronouncedly than surgical masks. Elderly cohort was more vulnerable to those effects. Exhaled humidity increased and exhaled oxygen decreased significantly over time. Breath profiles of endogenous aldehydes, hemiterpene, organosulfur, short-chain fatty acids, alcohols and ketone indicated cross-talks between physio-metabolic effects such as hypoxia, oxidative stress, hypoventilation, compartmental vasoconstriction, altered systemic bacterial activity and energy homeostasis. Concentrations of exogenous VOCs such as aromatics, nitrile and monoterpene depicted compartmental storage and washout. Breathomics allows unique physio-metabolic insights into side effects of face-mask wearing. Mask induced deoxygenation, oxidative stress, CO2 rebreathing, vasoconstriction and blood pressure fluctuations in elderly were clinically concerning (as leading towards hypoxia and hypoventilation). Intelligible global-pandemic policies should reconsider the type and wearing durations of recommended face-masks, based upon age and/or cardio-pulmonary conditions.

Quantitative Complexity Theory Used in the Prediction of Head-Up Tilt Testing Outcome

Background. Head-up tilt testing (HUTT), a well-established tool in the diagnosis of vasovagal syncope, is time-consuming, and every provoked vasovagal reaction may result in consolidating the reflex mechanism. Therefore, identification of parameters that could shorten the duration of HUTT and prevent fainting is desirable. Quantitative complexity theory (QCT) may provide holistic information on the cardiovascular reaction in HUTT. The aim of the present article was to evaluate the prognostic value of complexity in comparison with traditional haemodynamic parameters (HR and BP) in predicting the HUTT outcome. Methods. Eighty-one healthy volunteers (74 men; mean age: 37.8 years) were included in this retrospective analysis of data collected within the project realized in Department of Cardiology and Internal Diseases, Military Institute of Medicine between January 2012 and October 2014. The subjects underwent HUTT, with beat-to-beat haemodynamic monitoring with a Niccomo™. The chosen haemodynamic parameters (including BP, HR, stroke volume, cardiac output, systemic vascular resistance) have been used in complexity analysis. Results. HUTT was positive in 54 (66.7%) study participants. The values of complexity were already higher in fainting subjects than those were in nonfainting ones 300 s before HUTT termination (HUTT_end), with a significant upward trend starting 150 s before (pre)syncope. An area under the curve (AUC) over 0.700 was observed for complexity from 120 s before HUTT_end, with a sensitivity of 63% and specificity of 78% at this time point. The prognostic value of complexity was superior to that of the HR and mean arterial pressure (MAP). Conclusions. Complexity has been shown to be a sensitive marker of cardiovascular haemodynamic response to orthostatic stress and proved to be superior over HR and BP in predicting HUTT outcomes.