Influence of postural changes on haemodynamics in internal carotid artery bifurcation aneurysm using numerical methods

Cerebral intracranial aneurysms are serious problems that can lead to stroke,coma,and even death.The effect of blood flow on cerebral aneurysms and their relationship with rupture are unknown.In addition,postural changes and their relevance to haemodynamics of blood flow are difficult to measure in vivo using clinical imaging alone.Computational simulations investigating the detailed haemodynamics in cerebral aneurysms have been developed in recent times not only to understand the progression and rupture but also for clinical evaluation and treatment.In the present study,the haemodynamics of a patient-specific case of a large aneurysm on the left side internal carotid bifurcation(LICA)and no aneurysm on the right side internal carotid bifurcation(RICA)was investigated.The simulation of these patient-specific models using fluid–structure interaction provides a valuable comparison of flow behavior between normal and aneurysm models.The influences of postural changes were investigated during standing,sleeping,and head-down(HD)position.Significant changes in flow were observed during the HD position and quit high arterial blood pressure in the internal carotid artery(ICA)aneurysm model was established when compared to the normal ICA model.The velocity increased abruptly during the HD position by more than four times(LICA and RICA)and wall shear stress by four times(LICA)to ten times(RICA).The complex spiral flow and higher pressures prevailing within the dome increase the risk of aneurysm rupture.

Cardiovascular Haemodynamics and Some Biochemical Profiles of Endotoxemic Buffalo Calves on Infusion of HSS, Flunixin Meglumine &Blood

Six apparently healthy male buffalo calves aged between 6 months to one year with body weight range of 70 - 140 Kg were used in the present investigation. One animal was used for pilot trial for this group. Five calves were randomly taken into this group. The Eschrechia coli endotoxin infused i/v @5 mg/kg BW/hr for 3 hours to all the animals caused symptoms of restlessness, respiratory distress, snoring, diarrhea, profuse salivation along with the significant fall in systolic, diastolic, pulse and mean arterial venous pressure, hypoproteinemia at 1, 2 & 3 hour and hypoglycemia at 3rd hour i.e., end of endotoxin infusion. Respiration was increased significantly during endotoxin infusion at 2nd & 3rd hour and even afterwards till the end of the observation period i.e. 7 hrs. The treatment with hypertonic saline solution, flunixin meglumine and blood raised (p th, 6th & 7th hour respectively i.e., till the end of the observation period. There was no significant effect on Central Venous Pressure (CVP) and body temperature as measured from rectum.

Effect of flunixin meglumine alone and in combination on haemodynamics during bovine endotoxic shock and after treatment

To investigate the effect of Flunixin meglumine- a NSAID;alone and in combination with hypertonic saline on endotoxemic buffalo calves, two groups of five apparently healthy male buffalo calves aged be-tween 6-8 months were subjected to I.V. infusion of E.coli endotoxin at the rate of 5μg/kg BW per hour for 3 hours. A highly significant (P < 0.01) fall in mean systolic,diastolic, pulse, mean arterial pressure (M.A.P), central venous pressure (C.V.P) and haemo-globin was observed till the end of endotoxin infusion while respiratory rate was significantly elevated along with a non-significant alteration in rectal tem-perature and hematocrit during the infusion of en-dotoxin. Immediately at the end of endotoxin infusion, flunixin meglumine at the rate of 1.1 mg/kg B.W was infused i.v. in group-I animals and group-II animals were infused with hypertonic saline solution (H.S.S.) at the rate of 4 ml/Kg BW as one time infusion fol-lowed by flunixin meglumine at the rate of 1.1 mg/kg B.W which resulted in increase of various parameters either to normal or very close to normal value while the rectal temperature and haematocrit decreased non-significantly throughout the observation period of 7 hours. No improvement in Hb and respiration was observed consequent to FM administration. Both treatments successfully raised systolic, diastolic, pulse pressure, C.V.P & M.A.P to normal pre-infusion val-ues. From the results of the present investigation, it can be concluded that i.v. infusion of FM alone and in combination with hypertonic saline solution in en-dotoxemic buffalo calves effectively restores the various hemodynamic parameters close to normal pre-infusion values and it can be used as immediate resuscitation measure to provide the clinician valu-able time to plan further long term treatment.

Relation between Carotid Artery Plaques Characteristics as a Predictor of Haemodynamics Changes after Carotid Artery Stenting

Objectives: To study relationship between carotid artery plaques characteristics and haemodynamic changes after carotid stenting. Patients and Methods: This observational prospective (pilot) study included 20 patients—who underwent CAS. The study was carried out in Ain shams university hospitals—Railway hospital (ERMED) and Suez insurance hospital from December 2018 to February 2020. Inclusion criteria, Symptomatic (defined as amaurosis fugax, TIA, Minor stroke or Major stroke) stenosis > 70%. Asymptomatic stenosis > 80% (accidentally discovered during pre-operative assessment for CABG and during full assessment for irrelevant stroke). Results: Regarding to plaque character for degree of stenosis, calcification and ulceration revealed significantly higher degree of stenosis in hemodynamic events group (P = 0.024). On the other hand, that there was no statistically significant difference between the two groups as regard calcification, ulceration and lesion location. Conclusion: The study revealed that HI is a common occurrence following CAS procedures and significantly higher degree of stenosis in hemodynamic events group. Plaque shape, ulcerations hardly affect haeodynamic instability after carotid stenting.

Haemodynamics Simulation for Carotid Artery Bifurcation

Finite element method is used to simulate the haemodynamics for carotid artery bifurcation. The model geometry was constructed using in vivo measured dimensions, and in vivo flow waveforms in internal and external carotids and pressure in common carotid artery are used to specify the boundary conditions for simulation. Attentions are paid to the local flow pattern, secondary flow and wall shear stress distribution at the midsinus of internal carotid artery. It is found that flow separation occurs near the outer wall of the internal carotid sinus during the downstroke of systole, and thus induces reversed flow with low velocity. The flow separation is transient and results in the oscillation of wall shear stress from -2 to 6 dyne/cm 2. Secondary flow in the cross section of midsinus presents during the whole cardiac cycle, and the maximum circumferential velocity value is about one-third of the mean axial velocity at the same moment.

Associations between haemodynamics and wall enhancement of intracranial aneurysm

Background and purpose Previous studies have reported about inflammation processes(IPs)that play important roles in aneurysm formation and rupture,which could be driven by blood flow.IPs can be identified using aneurysmal wall enhancement(AWE)on high-resolution black-blood MRI(BB-MRI)and blood flow haemodynamics can be demonstrated by four-dimensional-flow MRI(4D-flow MRI).Thus,this study investigated the associations between AWE and haemodynamics in unruptured intracranial aneurysms(IA)by combining 4D-flow MRI and high-resolution BB-MRI.Materials and methods Between April 2014 and October 2017,48 patients with 49 unruptured IA who underwent both 4D-flow MRI and high-resolution BB-MRI were retrospectively included in this study.The haemodynamic parameters demonstrated using 4D-flow MRI were compared between different AWE patterns using the Kruskal-Wallis test and ordinal regression.Results The results of Kruskal-Wallis test showed that the average wall shear stress in the IA(WSSavg-IA),maximum through-plane velocity in the adjacent parent artery,inflow jet patterns and the average vorticity in IA(vorticityavg-IA)were significantly associated with the AWE patterns.Ordinal regression analysis identified WSSavg-IA(p=0.002)and vorticityavg-IA(p=0.033)as independent predictors of AWE patterns.Conclusion A low WSS and low average vorticity were independently associated with a high AWE grade for IAs larger than 4 mm.Therefore,WSS and average vorticity could predict AWE and circumferential AWE.

Haemodynamic management in brain death donors:Influence of aetiology of brain death

BACKGROUND In brain death donors(BDDs),donor management is the key in the complex donation process.Donor management goals,which are standards of care or clinical parameters,have been considered an acceptable barometer of successful donor management.AIM To test the hypothesis that aetiology of brain death could influence haemodynamic management in BDDs.METHODS Haemodynamic data(blood pressure,heart rate,central venous pressure,lactate,urine output,and vasoactive drugs)of BDDs were recorded on intensive care unit(ICU)admission and during the 6-h observation period(Time 1 at the beginning;Time 2 at the end).RESULTS The study population was divided into three groups according to the aetiology of brain death:Stroke(n=71),traumatic brain injury(n=48),and postanoxic encephalopathy(n=19).On ICU admission,BDDs with postanoxic encephalopathy showed the lowest values of systolic and diastolic blood pressure associated with higher values of heart rate and lactate and a higher need of norepinephrine and other vasoactive drugs.At the beginning of the 6-h period(Time 1),BDDs with postanoxic encephalopathy showed higher values of heart rate,lactate,and central venous pressure together with a higher need of other vasoactive drugs.CONCLUSION According to our data,haemodynamic management of BDDs is affected by the aetiology of brain death.BDDs with postanoxic encephalopathy have higher requirements for norepinephrine and other vasoactive drugs.

Imageology of internal carotid artery siphon in nonarteritic anterior ischaemic optic neuropathy

AIM:To evaluate whether narrowing of internal carotid artery siphon(ICAS)may increase the risk of developing non-arteritic anterior ischaemic optic neuropathy(NAION).METHODS:Totally 30 consecutive patients who had unilateral NAION and 30 gender-matched control subjects were recruited in the present study.The diameter of ICAS of all the participants were measured using head-and-neck computed tomographic angiography(CTA).Color doppler flow imaging(CDI)was used to measure the haemodynamics parameters of ICAS and short posterior ciliary arteries(SPCAs)in all subjects.Comparison of parameters between the NAION patients and controls as well as between the two sides within the patients were performed.The correlation between the diameter of ICAS and NAION was analyzed.RESULTS:A comparison of parameters between the affected side of the NAION patients and the controls,including the diameter of ICAS,the resistance index(RI)of ICAS,the blood flow velocities of SPCAs and RI of SPCAs,showed significantly difference(P<0.01),while there was no significant difference in terms of the mean blood flow velocity(Vm)of ICAS;Similar results were found while comparing all the measurements of the affected and unaffected side of patients(P for RI of SPCAs<0.05).No marked difference was detected in nearly all parameters except for RI of ICAS and SPCAs between the unaffected side of the NAION patients and the controls(P<0.05).The diameter of ICAS were significantly positive correlated with both peak systolic velocity(PSV)of SPCAs and end diastolic velocity(EDV)of SPCAs in patients with NAION(r=0.514,P<0.01 and r=0.418,P<0.05,respectively).CONCLUSION:Narrowing of ICAS may increase the risk of developing NAION.

Precision of a Parabolic Optimum Calculated from Noisy Biological Data, and Implications for Quantitative Optimization of Biventricular Pacemakers (Cardiac Resynchronization Therapy)

In patients with heart failure and disordered intracardiac conduction of activation, doctors implant a biven- tricular pacemaker (“cardiac resynchronization therapy”, CRT) to allow adjustment of the relative timings of activation of parts of the heart. The process of selecting the pacemaker timings that maximize cardiac function is called “optimization”. Although optimization—more than any other clinical assessment—needs to be precise, it is not yet conventional to report the standard error of the optimum alongside its value in clinical practice, nor even in research, because no method is available to calculate precision from one optimization dataset. Moreover, as long as the determinants of precision remain unknown, they will remain unconsidered, preventing candidate haemodynamic variables from being screened for suitability for use in optimization. This manuscript derives algebraically a clinically-applicable method to calculate the precision of the optimum value of x arising from fitting noisy biological measurements of y (such as blood flow or pressure) obtained at a series of known values of x (such as atrioventricular or interventricular delay) to a quadratic curve. A formula for uncertainty in the optimum value of x is obtained, in terms of the amount of scatter (irreproducibility) of y, the intensity of its curvature with respect to x, the width of the range and number of values of x tested, the number of replicate measurements made at each value of x, and the position of the optimum within the tested range. The ratio of scatter to curvature is found to be the overwhelming practical determinant of precision of the optimum. The new formulae have three uses. First, they are a basic science for anyone desiring time-efficient, reliable optimization protocols. Second, asking for the precision of every reported optimum may expose optimization methods whose precision is unacceptable. Third, evaluating precision quantitatively will help clinicians decide whether an apparent change in optimum between successive visits is real and not just noise.

Efficacy of propofol versus ketamine in modified electroconvulsive therapy: A prospective randomized control trial

Objective:To investigate the effects of propofol and ketamine on seizure duration,hemodynamics,and recovery of electroconvulsive therapy(ECT).Methods:This prospective randomized trial included patients who had undergone ECT under anesthesia.Patients received injection of propofol 1.5 mg/kg i.v.(the propofol group)or ketamine 0.8-1.2 mg/kg i.v.(the ketamine group)during ECT.Seizure duration,hemodynamics,and recovery were recorded and compared between the two groups.Results:This trial included 44 patinets with 22 patients receiving propofol and 22 patients receiving ketamine.The total dose of propofol and ketamine was(105.68±25.27)mg and(81.36±24.55)mg,respectively.The motor seizure and electroencephalogram seizure duration were prolonged in the ketamine group(P<0.001).The hemodynamics at the admission of the two groups were comparable(P>0.05);however,the mean systolic blood pressure during the procedure was significantly higher in the ketamine group(P=0.04).Besides,spontaneous eye-opening in the ketamine group took longer than that of the propofol group(P=0.001).Conclusion:Both propofol and ketamine are safe as anesthetic agents for modified ECT,and ketamine provides a longer seizure duration without hemodynamic instability or any significant complication.

Anaesthetic Management of Malignant Granulosa Cell Tumour of Ovary in a Paediatric Patient: A Case Report

Juvenile granulosa cell tumour (JGCT) is very uncommon gynaecological malignancy that occurs mostly commonly in less than five years of age. Only 0.1 percent of all ovarian tumours and 4 - 5 percent of granulosa cell tumours present as JGCT. The most common presentation of these tumours in children is precocious puberty. We describe anaesthetic management of a case of JGCT in a 1-year-old girl. The malignancy is assigned to International Federation of Gynaecology and Obstetrics staging system (FIGO stage I). It was treated with complete excision and histological examination confirmed the diagnosis.

Focus assessed transthoracic echocardiography (FATE) to diagnose pleural effusions causing haemodynamic compromise

The clinical assessment of patients with respiratory and circulatory problems can be complex, time consuming and have a high incidence of error. Bedside transthoracic ultrasound (US) is a useful adjunctive test in the evaluation of acutely unstable patients. This case series describes the use of the Focus Assessed Transthoracic Echocardiography (FATE) protocol to diagnose unsuspected pleural collections of fluid and how drainage significantly contributes to the haemodynamic improvement seen in these patients.

Duration of Cessation of Smoking before Elective Surgery: Impact on Intraoperative Hemodynamics and Early Postoperative Pain in Developing Country

Aim and Background: It is estimated that up to 20% of patients coming for elective surgery are smokers and carry a risk of perioperative complications. Though smoking cessation and its impact on perioperative outcome are widely investigated worldwide we were unable to find any data in Pakistan. The objective of the study is to determine the impact of the duration of smoking cessation before elective surgery on intraoperative hemodynamics and postoperative pain in Pakistani population. Methods: It was a prospective cohort study conducted at the Aga Khan University Hospital Karachi, Pakistan, for one-year duration. A total of 260 patients scheduled for elective noncardiac surgery under general anaesthesia were recruited. Surgery under regional anaesthesia and minor surgery under general anaesthesia were excluded. Data on self-reported duration of smoking cessation by patients, intraoperative haemodynamics, postoperative pain scores and duration of hospital stay were collected by independently trained data collectors from the preoperative area until the patient is discharged from the hospital. Results: A data from 256 patients were analyzed. On the basis of self-reported duration of preoperative smoking cessation, patients were divided into 4 groups (Group 1: less than 2 days, Group 2: more than 2 days to 7 days, Group 3: more than 7 days to 4 weeks and Group 4: more than 4 weeks). It was found that the longer the duration of cessation of smoking is the less haemodynamic changes and lower postoperative pain scores. Length of stay did not show any difference among all four groups. No major postoperative pulmonary complication was found in any study patient. Conclusions: Duration of cessation of smoking before elective surgery is a significant predictor of intraoperative haemodynamics and early postoperative pain in Pakistani population. A short duration of smoking cessation also helps to avoid some of the adverse effects and reduces perioperative complications.

The haemodynamic 3D simulation analysis of systemic-topulmonary shunts in infants with pulmonary stenosis

Background Systemic-to-pulmonary shunt(SPS) is an effective surgery for newborns diagnosed with atresia or severe pulmonary stenosis leading to insufficient pulmonary blood flow. However, there is no consistent conclusion on surgical plan chosen for the particular patient. Methods Shunt configurations including central shunt(CS) and MBTS(Right mb T innominate;Left m BT subclavian) were virtually reconstructed for newborn based on preoperative CT data. Candidate shunt configurations were evaluated based on the parameters that were computed from the flow simulations. Results Vortex occurred at the anastomosis of the shunt and the aorta for all three shunt configurations. For CS, it produced the highest pulmonary artery(PA) flow, with the shunt ratio of44.6%. Blood flow in LPA was 8.5% higher than blood flow in RPA. For MBTS, the indexed power loss(i PL)of Right m BT innominate configuration was lower than that of Left m BT subclavian, which was 28.4% and 36.1%respectively. Conclusions The anastomosis of the shunt and the aorta is prone to cause thrombosis. CS configuration is prone to cause hyperemia due to excessive pulmonary blood flow. So, it could be considered for patients without a risk of overflow. It also causes non-symmetric PA flow in favor of LPA. For Right m BT innominate,which has the lowest i PL, tends to produce smaller vortex regions compared to CS and Left m BT subclavian. As for Left m BT subclavian, vortex currents formed when blood flows into the LPA could prevent the formation of thrombosis.[S Chin J Cardiol 2019;20(4):217-227]