China
Africa
Explore chapters and articles related to this topic
Trauma Physiology and Metabolism
Published in Ian Greaves, Keith Porter, Jeff Garner, Trauma Care Manual, 2021
Ian Greaves, Keith Porter, Jeff Garner
The mean arterial pressure is the average pressure during the cardiac cycle and approximately equates to the diastolic pressure plus one-third of the pulse pressure. As the blood pressure is the product of the CO and SVR, it is subject to the influence of all the factors that can potentially affect its constituent components.
The patient with acute cardiovascular problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Figure 6.31 combines the waveforms seen on the ECG, arterial and CV pressure traces. The arterial waveform reflects the change in pressure seen in the arteries through the cardiac cycle. During systole (following the QRS complex on ECG), the pressure rises sharply until the maximum is reached. As the ventricles start to relax (signified by the T wave), pressure starts to fall. The closure of the aortic valve signifies the beginning of diastole and can be seen as the dicrotic notch on the pressure trace. End diastole pressure is reached, prior to the next ventricular contraction. Mean arterial pressure is calculated by the monitor and is often used to guide therapy.
The Systemic Circulation
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The mean arterial pressure, is the average arterial pressure acting during the cardiac cycle, is the driving force for blood flow and it can be measured by averaging the pressure recorded under an arterial pressure curve over time. The mean arterial pressure can be calculated approximately as being equal to the diastolic pressure plus one-third of the pulse pressure:
Association between ABO blood groups and preeclampsia
Published in Hypertension in Pregnancy, 2023
Hid Felizardo Cordero-Franco, Ana María Salinas-Martínez, Luis Ángel Garza-de Hoyos, Sofía Denisse González-Rueda, Joaquín Darío Treviño Báez, Francisco Javier Guzmán-de la Garza
The following clinical data were collected: systolic and diastolic blood pressure at the first antenatal visit (first trimester), history of gestational diabetes, and gestational weight gain (weight difference between the last and first antenatal visit). Obstetrical data included the number of pregnancies, inter-pregnancy interval in multiparous women, current multiple pregnancy, number of antenatal visits, fetal sex, and gestational age at the last antenatal visit. Medical history data included a history of preeclampsia/eclampsia, hypertension, type 2 diabetes, pre-pregnancy overweight/obesity (body mass index≥25 kg/m2), and aspirin use during pregnancy. Sociodemographic data included information on maternal age, education, and occupation. Neonatal data included the gestational age, birth weight, and one- and five-minute Apgar scores. Laboratory data included the blood group type and Rh factor. Blood groups were determined using the hemagglutination technique. All data were collected from electronic medical records. The mean arterial pressure was calculated from the systolic and diastolic blood pressures using the following formula: ([systolic blood pressure - diastolic blood pressure/3] + diastolic blood pressure).
Urine sodium excretion is related to extracellular water volume but not to blood pressure in 510 normotensive and never-treated hypertensive subjects
Published in Blood Pressure, 2023
Jyrki Taurio, Jenni Koskela, Marjatta Sinisalo, Antti Tikkakoski, Onni Niemelä, Mari Hämäläinen, Eeva Moilanen, Manoj Kumar Choudhary, Jukka Mustonen, Pasi Nevalainen, Ilkka Pörsti
However, some studies relying mainly on spot urine samples have suggested that also low Na+ intake may be harmful and elevate the risk of cardiovascular disease and mortality [9,10,48]. In the present study, 24-h urine Na+ excretion was not related with the level of BP, whether BP was measured by physician, research nurse, or recorded tonometrically in the laboratory. Moreover, urine Na+ excretion was not related to PWV, cardiac index, or SVR. In our study population, 279 subjects presented with elevated BP in the office, while the supine central BP values during laboratory measurements were predominantly within the normotensive range [1]. Thus, our findings agree with the views of a recent systematic Cochrane database review, which concluded that sodium reduction to the recommended levels would decrease mean arterial pressure by ∼0.4 mmHg in normotensive and by ∼4 mmHg in hypertensive subjects [40]. The reduction in BP may be considerably more pronounced in subjects with resistant hypertension [41].
Derivation and internal validation of a clinical prediction score to predict major effect or death in acute metamfetamine toxicity
Published in Clinical Toxicology, 2023
Rex Pui Kin Lam, Chi Keung Chan, Man Li Tse, Eric Ho Yin Lau, Zonglin Dai, Matthew Sik Hon Tsui, Timothy Hudson Rainer
Unlike other early warning scores, we did not divide individual physiological parameters, such as pulse rate, into different risk bands, in which extreme values at both ends of the spectrum are generally given a higher score [12–16]. We are aware that some physiological parameters might not have a linear association with poor clinical outcomes. For instance, patients with severe bradycardia and tachycardia are both at risk of major effect or death. However, using the risk-band approach warrants the use of a scoring chart or software in score calculation, adding to the cognitive load of the users. We dichotomized physiological parameters for ease of use and weighed individual parameters with whole numbers to simplify the calculation. For parameters such as pulse rate, mean arterial pressure should be low if the bradycardia is severe enough to cause hemodynamic instability. Despite being a simpler scoring system based on dichotomized variables, the MASCOT score still performed well compared with existing early warning scores within the validation cohort, in which the pattern of drug use and occurrence of major effect or death were different from the derivation cohort. This indicates that model overfitting is less likely and the score is robust in different populations. Although the point estimate of the AUROC of the MASCOT score was lower than that of the MEWS, MEWS with GCS, and NEWS2, their 95% CIs overlapped considerably, making it difficult to confirm the superiority of one scoring system over the others.