Magnitude Of Hemodynamic Changes Research Articles

The incidence and magnitude of hemodynamic changes after subarachnoid block in patients with pre-eclampsia undergoing caesarean section at LD Hospital SMHS GMC Srinagar: An observational study

The incidence and magnitude of hemodynamic changes after subarachnoid block in patients with pre-eclampsia undergoing caesarean section at LD Hospital SMHS GMC Srinagar: An observational study

Hemodynamics of the sternocleidomastoid measured with frequency domain near-infrared spectroscopy towards non-invasive monitoring during mechanical ventilation.

Mechanical ventilation (MV) is used to assist spontaneous breathing in critically ill patients in the intensive care unit (ICU). MV is a cornerstone of critical care medicine but it is now known that inspiratory muscle dysfunction due to injury, disuse, and/or atrophy during MV plays a major role in outcomes for these patients. For example, prolonged MV is strongly correlated with dysfunction of the sternocleidomastoid (SCM), an accessory inspiratory muscle that has been linked to weaning failure from MV. Hemodynamic monitoring of the SCM may provide an important non-invasive and real-time means to monitor MV. In this work, we first conducted multi-layer Monte Carlo simulations to confirm the ability of near infrared light to detect changes in the oxygenation of the SCM over wide ranges of skin tones and adipose layer thicknesses. We then optimized a custom digital frequency domain near-infrared spectroscopy (FD-NIRS) system for continuous 10 Hz measurements of the SCM at 730 nm and 850 nm. A healthy volunteer study was conducted (N=10); subjects performed sets of isometric neck flexions of the SCM. Substantial changes in oxyhemoglobin + oxymyoglobin (oxy[Hb + Mb]), deoxyhemoglobin + deoxymyoglobin (deoxy[Hb + Mb]), and total hemoglobin + myoglobin (total[Hb + Mb]) were observed during sustained and intermittent isometric flexions. There were notable sex differences observed in the magnitude of hemodynamic changes (∼2x larger changes in males for oxy[Hb + Mb] and deoxy[Hb + Mb]). The magnitude of hemodynamic changes when taking into account µs' changes during flexions was ∼ 2-2.5x larger as compared to assuming constant scattering (CS), which is a common assumption used for continuous wave (CW) NIRS methods. This study suggests that FD-NIRS provides improved accuracy for hemodynamic monitoring of the SCM compared to CW-NIRS, and that FD-NIRS may provide value for SCM monitoring during MV.

Hemodynamic changes after spinal anesthesia in preeclamptic patients undergoing cesarean section at a tertiary referral center in Ethiopia: a prospective cohort study

BackgroundSpinal anesthesia-induced maternal hypotension is the most frequent complication associated with maternal morbidity and mortality during Cesarean section. The aim of this study was to compare the incidence and magnitude of hemodynamic changes in preeclamptic and non-preeclamptic parturients undergone Cesarean section under spinal anesthesia.MethodA prospective cohort study was conducted from 01 February to 28 May 2019 in preeclamptic and non-preeclamptic parturients. We hypothesized preeclamptic parturients are at high risk of spinal anesthesia induced hypotension than non preeclamptics. A total of 122 ASA II and ASA III parturients were recruited consecutively and assigned to two groups (81non-preeclamptics, and 41 preeclamptics). Parturients with cardiac disease, twin pregnancy, chronic hypertension, gestational hypertension, superimposed hypertension, renal disease, diabetes mellitus, coagulopathy (platelet count < 80 × 109/L), active labor, eclampsia, abruptio placentae, placenta praevia, any adjuvant added with local anesthetics were excluded. The data analysis was done using SPSS version 22 statistical software. Student t test, MannWhitney U test and Fisher exact test were used to compare the data. All P values < 0.05 were considered statistically significant.ResultThe incidence of spinal anesthesia-induced hypotension was higher in non-preeclamptic parturients than preeclamptic parturients (55.6% vs. 34.1%, respectively) and the degree of blood pressure drop was significantly greater in the non-preeclamptic parturients compared to those with preeclampsia; As well intraoperative fluid consumption was significantly greater in the non-preeclamptics parturients compared to those with preeclamptics.ConclusionThe incidence and magnitude of spinal anesthesia-induced hypotension in parturients undergone Cesarean section were less in preeclamptic parturients than in non-preeclamptic parturients.. Based on the data from this study we recommended spinal anesthesia for preeclamptic patients, unless there is a contra indication based on preeclampsia.

Haemodynamic Stability After Paracervical Block: A Randomized, Controlled, Double-blind Study Comparing Bupivacaine-Adrenaline With Bupivacaine

(Acta Anaesthesiol Scand. 2018. Doi:10.1111/aas.13259) For gynecologic procedures involving the cervix or uterus, long-acting local anesthetics like bupivacaine, administered via paracervical block, can provide a significant reduction in postoperative pain scores. Adrenaline can be added to local anesthetics to reduce toxicity potential. However, there are few data available regarding the frequency and magnitude of hemodynamic changes in patients when adrenaline is added to local anesthetics. In this randomized controlled trial, the authors examined hemodynamic stability after paracervical block in healthy patients given bupivacaine with and without adrenaline.

Circulatory responses to epidural blockade of treated and untreated hypertensive patients.

The circulatory effects of epidural blockade were studied in 82 hypertensive patients. To compare the circulatory responses to epidural blockade between treated and untreated hypertensive patients, patients were divided into 60 treated and 22 untreated hypertensive patients groups, and to confirm the magnitude of hemodynamic changes according to the segment of epidural approach, each group was then subdivided into 3 groups as cervical, thoracic and lumbar. The blood pressure and the pulse rate were measured before and after establishment of epidural blockade. The baseline blood pressure of untreated group was significantly higher than that of treated one (P < 0.05), but there was no difference between two groups in the initial pulse rate. At 20 min after meperidine administration to epidural space, blood pressure drop was more pronounced in untreated thoracic subgroup than in treated one (P < 0.05), but there was no significant difference in blood pressure drop between treated and untreated groups of cervical and lumbar blockade. Regarding the pulse rate change, there was no significant difference between treated and untreated cases of all the subgroups. The rate of fluid load required to maintain the adequate blood pressure in the first 20 min of epidural blockade was more in treated than in untreated cases of cervical subgroup. During surgery the administration of vasopressor agents was more frequently required to maintain blood pressure in treated and untreated thoracic subgroups, while the administration of vasodilator agents was more frequent in treated and untreated cases of cervical and thoracic subgroups. The incidence of rebound hypertension was relatively high in untreated cervical and thoracic subgroups as compared to treated ones.

Body composition and its relation to systemic haemodynamics, fluid volume partitions and energy utilization in rats with bilateral ventromedial hypothalamic lesions.

Body composition and its relationship with intra-arterial pressure, fluid volume partitions and oxygen consumption were studied in male rats four months following ventromedial hypothalamic (VMH) destruction during the static phase of the development of obesity. Compared with sham-operated controls, rats with VMH lesions had a greater body weight which was related to an increased body lipid content and an elevated arterial pressure and total peripheral resistance. Fluid volume distribution was normal and total body oxygen consumption (per unit of body weight) was reduced. Bilateral destruction of the ventromedial hypothalamus was confirmed in each of the rats studied and no relationship could be demonstrated between the lesion size and the magnitude of haemodynamic changes. It is concluded that the increased arterial pressure observed in obese VMH lesioned rats was directly related to an elevated total body lipid content.

The pacing stress test reexamined: Correlation of pacing-induced hemodynamic changes with the amount of myocardium at risk

To assess the relation between extent of ischemia and the magnitude of hemodynamic changes, 25 patients (5 with normal coronary arteries and 20 with significant coronary obstructive disease) were studied with rapid atrial pacing and thallium scintigraphy at the time of cardiac catheterization. Hemodynamic variables were measured before, during and after maximal pacing. Thallium was injected intravenously during maximal pacing and scans in three standard views were obtained immediately in the catheterization laboratory, with delayed scans obtained 4 hours after the cessation of pacing. The three thallium scans were each subdivided into five segments, and a thallium score was obtained on the basis of the total number of segments that were hypoperfused. Each patient was assigned a total thallium score corresponding to thallium defects at maximal pacing, as well as a redistributed thallium score corresponding to the difference between thallium score at maximal pacing and that 4 hours later. With pacing, patients with normal coronary arteries demonstrated no significant change in baseline hemodynamic variables, whereas patients with coronary artery disease exhibited a decrease in cardiac index, an increase in systemic vascular resistance, a widening of arteriovenous oxygen difference, an increase in pulmonary capillary wedge pressure and mean pulmonary artery pressure during maximal pacing and an increase in left ventricular end-diastolic pressure immediately after pacing. There was a significant correlation (Spearman rank r = 0.64, p less than 0.01) between redistributed thallium score and an increase in left ventricular end-diastolic pressure in the postpacing period. Moreover, there was an even higher correlation (Spearman rank r = 0.90, p less than 0.001) between total thallium score and the postpacing increase in end-diastolic pressure. It is concluded that in patients with coronary artery disease the magnitude of pacing-induced hemodynamic changes reflects both the amount of myocardial tissue at ischemic jeopardy and the total mass of hypoperfused myocardium during maximal pacing stress.

Comparative plasma catecholamine and hemodynamic responses to handgrip, cold pressor and supine bicycle exercise testing in normal subjects

Serial hemodynamic and plasma catecholamine responses were compared among 10 healthy men (27 +/- 3 years) (+/- 1 standard deviation) during symptom-limited handgrip (33% maximal voluntary contraction for 4.4 +/- 1.8 minutes), cold pressor testing (6 minutes) and symptom-limited supine bicycle exercise (22 +/- 5 minutes). Plasma catecholamine concentrations were measured by radioenzymatic assays: ejection fraction and changes in cardiac volumes were assessed by equilibrium radionuclide angiography. During maximal supine exercise, plasma norepinephrine and epinephrine concentrations increased three to six times more than during either symptom-limited handgrip or cold pressor testing. Additionally, increases in heart rate, systolic blood pressure, rate-pressure product, stroke volume, ejection fraction and cardiac output were significantly greater during bicycle exercise than during the other two tests. A decrease in ejection fraction of 0.05 units or more was common in young normal subjects during the first 2 minutes of cold pressor testing (6 of 10 subjects) or at symptom-limited handgrip (3 of 10), but never occurred during maximal supine bicycle exercise. The magnitude of hemodynamic changes with maximal supine bicycle exercise was greater, more consistent and associated with much higher sympathetic nervous system activation, making this a potentially more useful diagnostic stress than either handgrip exercise or cold pressor testing.