Direct Blood Pressure Measurements Research Articles

Measurement of blood pressure in rats: Invasive or noninvasive methods?

Experiments should always be based on control values. This assumption fully applies to cardiovascular parameters, such as heart rate (HR) and blood pressure (BP), which are highly sensitive to various external and internal stimuli and can already be significantly altered when an experiment begins. Therefore, it is necessary to determine which values are defined as a starting point (i.e., control and baseline) or compare them with valid reference values if the goal is to evaluate the changes after experimental intervention. A generally accepted principle is a reciprocal relationship between BP and HR, in which one parameter affects the other and vice versa. BP can be measured using two methods-noninvasively (tail-cuff) and invasively (telemetry, direct measurements of BP after introducing the sensor directly into the artery), and HR directly or by extrapolation from BP recordings. This study does not aim to evaluate the results of individual studies, but to review whether there are differences in control (baseline) BP values in normotensive and hypertensive male rats using invasive versus noninvasive methods, and to investigate whether there is a causal relationship between BP and HR in invivo experiments with male rats.

Vascular dysfunction occurs prior to the onset of amyloid pathology and Aβ plaque deposits colocalize with endothelial cells in the hippocampus of female APPswe/PSEN1dE9 mice.

Increasing evidence shows that cardiovascular diseases (CVDs) are associated with an increased risk of cognitive impairment and Alzheimer's diseases (AD). It is unknown whether systemic vascular dysfunction occurs prior to the development of AD, if this occurs in a sex-dependent manner, and whether endothelial cells play a role in the deposition of amyloid beta (Aβ) peptides. We hypothesized that vascular dysfunction occurs prior to the onset of amyloid pathology, thus escalating its progression. Furthermore, endothelial cells from female mice will present with an exacerbated formation of Aβ peptides due to an exacerbated pressure pulsatility. To test this hypothesis, we used a double transgenic mouse model of early-onset AD (APPswe/PSEN1dE9). We evaluated hippocampus-dependent recognition memory and the cardiovascular function by echocardiography and direct measurements of blood pressure through carotid artery catheterization. Vascular function was evaluated in resistance arteries, morphometric parameters in the aortas, and immunofluorescence in the hippocampus and aortas. We observed that endothelial dysfunction occurred prior to the onset of amyloid pathology irrespective of sex. However, during the onset of amyloid pathology, only female APP/PS1 mice had vascular stiffness in the aorta. There was elevated Aβ deposition which colocalized with endothelial cells in the hippocampus from female APP/PS1 mice. Overall, these data showed that vascular abnormalities may be an early marker, and potential mediator of AD, but exacerbated aortic stiffness and pressure pulsatility after the onset of amyloid pathology may be associated with a greater burden of Aβ formation in hippocampal endothelial cells from female but not male APP/PS1 mice.

ROLE OF THE NURSE IN MANAGING INVASIVE BLOOD PRESSURE MONITORING

Abstract Introduction Arterial blood pressure (BP) monitoring is an invasive system for directly tracking and measuring BP and finds its use in critically ill patients who require continuous hemodynamic monitoring and frequent arterial blood test. [1] Invasive monitoring requires the use of sophisticated equipment and specific skills for its management, which influence the quality of care, including the introduction of a catheter inside the arterial vessel. [2] Intra–arterial catheterization is considered the Gold Standard for a direct measurement of BP. [3] Therefore, the objective of this work is to outline the role of the nurse in the management of invasive BP monitoring, with particular attention to the possibility of independently managing the positioning of the arterial cannula itself. Materials and Methods A review was performed on the management of invasive BP monitoring, with a particular focus on the role of the nurse in arterial cannula positioning. The Pubmed database was consulted. The search strategy involved the use of Mesh terms and free terms, including "Hemodynamic Monitoring" “Vascular Access Devices” “Critical Care Nursing” “Arterial cannulation”. The terms used were combined together using the Boolean operator “AND”. The Code of Conduct for the Nursing ProfessionsMand the National Collective Labor Agreement were also examinatedand, along with everyday practice of professionals in this field of action. Results There are no studies in literature that clearly outline the role of the different professional figures in the management of invasive BP monitoring and there are no clear references regarding who is responsible for positioning the arterial cannula. The development of continuing education programs in the area of clinical reasoning skills for hemodynamic monitoring should be more emphasized. Furthermore, we should focus more on improving practical skills for hemodynamic monitoring. [4] Conclusions Advanced skills need to be officially acknowledge to the expert professional by the institutions they belong to, which should contribute to training by creating accredited company courses. Not only to protect assisted people and the professional, but also in order to enhance their work and give it the right recognition. Subsequently, studies could be carried out to evaluate the effective reduction in latency times between non–invasive monitoring and invasive monitoring on critically ill patients, if managed by the nurse.

Testosterone enhances adipose tissue-blood pressure axis in obese mice exposed to early life stress

Previously, we have shown that male and female mice exposed to maternal separation and early weaning (MSEW), a model of early life stress, display exacerbated obesity-induced hypertension in response to chronic high fat diet. However, only male mice showed higher sympathetic tone at baseline, along with increased neuronal activation in PVN and pressor response to the acute stimulation of TRVP1 channels with capsaicin, a mechanism known as adipose afferent reflex (AAR). The aim of this study was to investigate whether obese male MSEW mice show 1) increased intracellular calcium in response to capsaicin in neuronal cultures of dorsal ganglia root (DRG), and 2) a role for sex hormones in AAR reactivity in vivo. Six-months-old control and MSEW fed a high fat diet (HFD, 60% kcal fat) were injected with pAAV-CAG-tdTomato (59462-PHP.S, 1012 viral particles); 8 sites; 4 ul/site; bilateral). After 6 weeks, mice were decapitated and DRGs (L5-T12) were collected and placed in ice-cold HBSS solution, dissociated and mixed with Collagenase P (1 mg/ml in HBSS, 15 min, 37 oC). After 0.25% Trypsin-EDTA incubation, neurons were mechanically dissociated, collected by centrifugation and resuspended in DMEM-10% FBS, plated onto the Matrigel Basement Membrane Matrix covered coverslips and maintained at 37 oC for 15-16 hours. Neuronal cultures were incubated in Ca2+ imaging solution with 2 μM Fura-2 AM, 30 min in dark conditions. After de-estirification, intracellular Ca2+ transients were visualized by exciting Fura-2 at 340 ± 20 nm and 380 ± 20 nm using a high-speed filter changer to obtain a ratiometric value independent of indicator concentration. Emitted light was passed through a dichroic filter (400-nm high pass) and an emitter filter (520 ± 30 nm) and was digitized onto the sensor of an EMCCD camera. Background subtraction and normalization to baseline were used to quantify changes in fluorescence. Despite similar resting uncalibrated ratios of calcium levels between groups (~0.6 ratio units, n=3), sensory neurons from MSEW mice tended to display larger responses to capsaicin (50 uM), showing elevated calcium kinetics vs. controls (0.56±0.09 vs. 0.31±0.12 delta ratio, respectively, p=0.063) as well as longer transients, perhaps indicative of reduced clearance or buffering. A separate set of age-matched mice were gonadectomized. After 4 weeks, anesthetized mice were fitted with carotid artery catheter for direct blood pressure measurement in response to the infusion of perigonadal fat with capsaicin (1.5 pmol/μL during 2 minutes in 4 sites, bilaterally). Capsaicin-induced pressor response was exacerbated in intact MSEW male mice compared to intact controls (9.0±0.2 vs. 1.3±0.2 delta mmHg, respectively, n=6, p<0.05). Orchidectomy attenuated delta blood pressure in MSEW mice to 7.0±0.2 mmHg (p<0.05 vs. intact MSEW), while enhanced delta blood pressure in control mice to 7.5±0.2 mmHg (p<0.05 vs. intact control). MSEW did not influence the pressor response to perigonadal fat stimulation with capsaicin either in intact or ovariectomized obese female mice (n=4-6 per group, p>0.05), suggesting that estradiol may not to play a protective role in obese females AAR reactivity. This data indicates that testosterone could buffer the AAR reactivity of obese control mice, while MSEW exerts an opposite effect. Thus, investigating testosterone signaling on calcium handling mechanisms (i.e., buffers, pumps, ER-mediated calcium release) in sensory neurons innervating visceral fat will provide insights on the sex-specific contribution of afferent sympathoexitatory signals to obesity-hypertension in male MSEW mice. This study was supported by NIH R01 HL135158, and SALT pilot - University of Kentucky to ASL. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A Custom-Tailored Multichannel Pressure Monitoring System Designed for Experimental Surgical Model of Abdominal Compartment Syndrome.

In experimental medicine, a wide variety of sensory measurements are used. One of these is real-time precision pressure measurement. For comparative studies of the complex pathophysiology and surgical management of abdominal compartment syndrome, a multichannel pressure measurement system is essential. An important aspect is that this multichannel pressure measurement system should be able to monitor the pressure conditions in different tissue layers, and compartments, under different settings. We created a 12-channel positive-negative sensor system for simultaneous detection of pressure conditions in the abdominal cavity, the intestines, and the circulatory system. The same pressure sensor was used with different measurement ranges. In this paper, we describe the device and major experiences, advantages, and disadvantages. The sensory systems are capable of real-time, variable frequency sampling and data collection. It is also important to note that the pressure measurement system should be able to measure pressure with high sensitivity, independently of the filling medium (gas, liquid). The multichannel pressure measurement system we developed was well suited for abdominal compartment syndrome experiments and provided data for optimizing the method of negative pressure wound management. The system is also suitable for direct blood pressure measurement, making it appropriate for use in additional experimental surgical models.

Excessive Sodium and Insufficient Potassium Consumption Can Elevate the Risk of Developing Hypertension

Introduction. Physiologically, there are setbacks and weaknesses in body functions in the elderly. This can cause inadequate food intake or eating imbalances in the elderly. Increased blood pressure is influenced by many factors such as sodium and potassium intake and less potassium intake can increase blood pressure. The purpose of this study was to determine the relationship of sodium and potassium intake from food with blood pressure in the elderly in the community dr. Mohammad Hoesin Hospital. Methods. An observational-analytic study was conducted on 120 elderly people using a cross-sectional research design conducted in the elderly community of dr. Mohammad Hoesin Hospital in October-November 2019. The sample of this study were members of the elderly community aged over 60 years, present when the study was conducted, willing to become a respondent and signed an informed consent. Data was obtained through filling out food record questionnaires, food recall interviews, personal data interviews, and direct measurement of blood pressure and nutritional status. To meet the research objectives, data were analyzed by Chi-square test. Results. In this study, there were 120 elderly people consisting of 3 men and 117 women. There was a significant relationship between sodium and potassium intake and blood pressure (p=0,003 and p=0,0001). Conclusion. There is a significant relationship between sodium and potassium intake with blood pressure in the elderly.

ARTERIAL CATHETERIZATION IN GREAT APES.

Anesthesia is frequently required to provide appropriate medical care to captive great apes. Anesthetic safety can be optimized through placement of an arterial catheter, which allows direct measurement of arterial blood pressure and easy sampling of arterial blood for blood-gas analysis. Arterial catheterization in great apes can be achieved through palpation-guided or ultrasound-guided placement with or without a modified Seldinger technique. Potential sites for arterial catheterization include the anterior tibial artery, caudal tibial and posterior saphenous arteries, dorsal pedal artery, femoral artery, radial artery, and brachial artery. Arterial catheterization is recommended for lengthy great ape anesthetic procedures or those involving invasive procedures.

Edukasi Pencegahan Hipertensi pada Usia Produktif

Hypertension is a condition of systolic pressure above 140 mmHg and diastolic pressure above 90 mmHg. Prevention of hypertension can be done by controlling a healthy lifestyle including controlling sleep habits, eating habits, weight control, not smoking or drinking alcoholic beverages, exercising exercise regularly and can manage stress. The purpose of this service is to provide education on prevention of hypertension at a productive age for prevention of hypertension in the hope of reducing morbidity due to hypertension in the community. The method used is education, discussion, distribution of leaflets regarding hypertension material, the implementation of this service is carried out through several stages, namely direct measurement of blood pressure, implementation of education and distribution of leaflets. The number of participants in the extension was 25 people. The results obtained during the community trial show that people of productive age know what precautions can be taken to prevent hypertension. It is hoped that this community service activity will continue.

Association Between Sleep Efficiency and Hypertension in Chinese Obstructive Sleep Apnea Patients.

We aimed to explore the relationship of sleep efficiency (SE) with the prevalence of hypertension in Chinese obstructive sleep apnea (OSA) patients based on polysomnography (PSG) records. We studied 2360 patients with OSA and 764 primary snorers who underwent PSG in our hospital. SE was divided into three grades, including ≥85%, 80%~84.9%, and <80%. Hypertension was defined based either on direct blood pressure measurements, under anti-hypertensive treatments or on physician diagnosis. Multivariate logistic regression models were conducted to investigate the association between SE and hypertension. After adjusting for potential confounding factors, OSA patients with <80% SE and those with 80% to 84.9% SE were significantly associated with the prevalence of hypertension (OR = 1.248, 95% CI 1.018~1.531, P=0.033; OR = 1.380, 95% CI 1.040~1.832, P=0.026). Compared to primary snorers, OSA combined with <85% SE increased the odds of hypertension. In stratified analysis by SE, risk of hypertension only in those with <80% SE was significantly different between OSA and primary snorers. Furthermore, this relationship between reduced SE and hypertension was evident especially in female, younger ages, obese, moderate and severe OSA patients. No significant relationship between reduced SE and hypertension was found in primary snores group. We found that poor SE was correlated with the prevalence of hypertension in Chinese OSA patients, but not in those with primary snoring. Moreover, this relationship was evident especially in female, younger ages, obese, moderate and severe OSA patients.

Determinan Kejadian Hipertensi pada Ibu Hamil Di Puskesmas Purwokerto Utara II

The Maternal Mortality Rate (MMR) is an indicator to see the success of maternal health efforts. MMR in Banyumas Regency in 2019 was 38 per 100,000 live births and in 2020 it was 41.55 per 100,000 live births. The most common causes of MMR in Banyumas Regency are preeclampsia, bleeding during pregnancy, childbirth and the puerperium accompanied by complications from comorbidities. Maternal deaths usually occur because of the high cases of pregnant women with high risk. Factors that influence the incidence of preeclampsia can be interrelated and influence one another. Knowing the risk factors for hypertension in pregnancy is useful for the health care system for pregnant women to monitor risk groups from early pregnancy to the second trimester. The purpose of this study was to determine the determinants of the incidence of hypertension in pregnant women at the North Purwokerto II Health Center. The research design is a cross sectional study. Respondents in this study were pregnant women at the Purwokerto Utara 2 Public Health Center, Banyumas Regency. Data was taken in August - September 2022 using a questionnaire and direct blood pressure measurements. Samples were taken using total sampling technique with a total of 67 respondents. Statistical tests used univariate analysis (frequency distribution) and bivariate analysis using the fisher's exact formula (p &lt;0.5). The results of this study were that there were no factors related to the incidence of hypertension in pregnant women at the Purwokerto Utara II Health Center with a p value &gt; 0.05. There is no relationship between maternal age, gestational age, parity, occupation, education level, socioeconomic status, family history of hypertension, overweight and use of contraceptives with hypertension in pregnant women at the Purwokerto Utara II Health Center.

Hubungan Aktivitas Fisik dengan Tekanan Darah pada Mahasiswa Fakultas Kedokteran Universitas HKBP Nommensen Medan di Masa Pandemi COVID-19

Background: Blood pressure is a very important factor in the body's circulatory system. If there is an increase ordecrease in blood pressure it will affect the balance in the body. High blood pressure, also known as hypertension, affects many people around the world, including in Indonesia itself. One of the factors that affect blood pressure is physical activity.Objective: This study aimed to determine the association between physical activity and blood pressure of students in the Faculty of Medicine, Universitas HKBP Nommensen Medan.Methods: This study was an analytic study with a cross-sectional design. Total respondents was 90 students who were selected using purposive sampling method. This study used primary data, namely a questionnaire to fill in the history of physical activity and direct blood pressure measurements. The association between physical activity and blood pressure was analyzed using the Chi-Square test.Results: In this study, it was found that the majority of respondents were classified as active (74.4%) and had normal blood pressure (74.4%). The results of the Chi-Square test found that there was no association between physical activity and blood pressure in students of the Faculty of Medicine, Universitas HKBP Nommensen Medan (p = 0.240).Conclusion: There is no association between physical activity and blood pressure in students of the Faculty of Medicine, Universitas HKBP Nommensen Medan, during the COVID-19 pandemic.

EVALUATION OF AGREEMENT BETWEEN OSCILLOMETRIC AND DIRECT BLOOD PRESSURE MEASUREMENTS IN ANESTHETIZED TIGERS (PANTHERA TIGRIS).

Noninvasive blood pressure measurement is commonly performed with oscillometry; however, this technique provides clinically helpful information only if it is representative of the gold standard. Agreement between direct and oscillometric blood pressure measurements were performed in 14 anesthetized, captive tigers (Panthera tigris). A cuff, placed around the tail base and connected to a multiparameter monitor, was used to measure arterial blood pressure oscillometrically and provided systolic, mean, and diastolic pressures. At the same time, direct blood pressures were obtained from a dorsal pedal arterial catheter, and the oscillometric and direct readings were considered paired data points. Agreement between the two methods was evaluated by Bland-Altman plots. All animals completed the study and provided 196 paired data points. The bias (mm Hg) for systolic, mean, and diastolic arterial pressures was -3.7, -0.8, and -1.6, respectively. Limits of agreement (mm Hg) for systolic, mean, and diastolic arterial pressures were -31 to 24, -29 to 27, and -29 to 26, respectively. Oscillometry provided an acceptable amount of readings within 10 and 20 mm Hg of the gold standard. The oscillometric technique provided reasonable agreement with direct measurements. Therefore, in the conditions used in this study, oscillometric blood pressure measured via the ventral coccygeal artery provided reasonable estimates of invasive blood pressure in anesthetized tigers.

Dietary Fats and Cardio-Metabolic Outcomes in a Cohort of Italian Adults.

Background: Dietary fats, and especially saturated fatty acid (SFA), have been blamed for being the culprit in the dramatic increase in obesity and its associated diseases. However multiple systematic reviews and recent meta-analyses do not support the association between SFA and cardiovascular diseases. Thus, the objective of this study was to test whether specific types and subtypes of dietary fats are associated with metabolic outcomes in a cohort of Italian adults. Methods: Nutritional and demographic data of 1936 adults living in the south of Italy were examined. Food frequency questionnaires (FFQs) were administered to assess the intake of total dietary fat and each specific class of dietary fat, such as SFA, monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA). The intake of fatty acids was also examined according to the carbon-chain length of each individual class. Cases of hypertension, type-2 diabetes and dyslipidemias were collected from previous doctor-confirmed diagnosis records (or direct measurement of blood pressure). Results: After adjustment for potential confounding factors, individuals reporting higher intakes of total and saturated fats were associated with lower likelihood of having hypertension (odds ratio (OR) = 0.57, 95% CI: 0.35, 0.91 and OR = 0.55, 95% CI: 0.34, 0.89, respectively). Moreover, higher intake of short-chain saturated fatty acids (SCSFAs) and medium-chain saturated fatty acids (MCSFAs) was inversely associated with dyslipidemia and diabetes (OR = 0.43, 95% CI: 0.23, 0.82 and OR = 0.25, 95% CI: 0.09, 0.72, respectively). Among MUFAs, C18:1 was inversely associated with hypertension and diabetes (OR = 0.52, 95% CI: 0.30, 0.92 and OR = 0.21, 95% CI: 0.07, 0.67, respectively), while C14:1 intake was inversely associated only with hypertension (OR = 0.57, 95% CI: 0.37, 0.88). In contrast, C20:1 intake was associated with dyslipidemia (OR = 3.35, 95% CI: 1.33, 8.42). Regarding PUFA, C18:2 and 20:5 were inversely associated with hypertension (OR = 0.33, 95% CI: 0.18, 0.60 and OR = 0.30, 95% CI: 0.10, 0.89, respectively). Conclusions: The consumption of SFA does not seem to be harmful to cardio-metabolic health and, on the contrary, SCSFA may exert beneficial effects. Further studies are needed to clearly validate the results of the present study.

Ivabradine treatment lowers blood pressure and promotes cardiac and renal protection in spontaneously hypertensive rats

Hypertension is linked to hyperpolarization-activated cyclic nucleotide-gated (HCN) function, expressed in excitable and non-excitable cells. Considering that the reduction in heart rate (HR) improves coronary perfusion and cardiac performance, ivabradine (IVA) emerged as an important drug for the treatment of cardiovascular diseases. AimEvaluate if IVA chronic treatment effect can mitigate hypertension and reverse the cardiac and renal damage in SHR. Main methodsRats were divided into 4 groups treated for 14 days with PBS (1 ml/kg; i.p) or IVA (1 mg/kg; i.p): 1) WKY PBS; 2) SHR PBS; 3) WKY IVA; and 4) SHR IVA. The systolic blood pressure (SBP) was measured, indirectly, before and during the treatment period with IVA (day 0, 1, 7 and 11). Rats were subjected to artery cannulation for direct blood pressure (BP) measurement. Morphofunctional and gene expression were evaluated in the heart and kidneys. Key findingsIVA reduced SBP only in SHR on the 7th day. Direct blood pressure measurement showed that IVA chronic treatment reduced HR in the SHR. Interestingly, mean arterial pressure (MAP) was reduced in SHR IVA when compared to SHR PBS. Serum and urinary biochemical data were not altered by IVA. Moreover, IVA reduced the renal inflammatory infiltrates and increased glomerular density, besides preventing the cardiac inflammatory and hypertrophic responses. SignificanceIVA treatment lowered blood pressure, improved cardiac remodeling and inflammation, as well as decreasing renal damage in SHR. Further, IVA increased renal HCN2 mRNA and reduced cardiac HCN4 mRNA.

Use of vasopressors for treatment of vasodilatory hypotension in dogs and cats by Diplomates of the American College of Veterinary Emergency and Critical Care.

To identify the most common practices of Diplomates of the American College of Veterinary Emergency and Critical Care (DACVECCs) as they relate to the recognition and treatment of hypotension in dogs and cats, particularly concerning the use of vasopressors in vasodilatory shock states. A survey regarding vasopressor use was sent to all active DACVECCs using the Veterinary Information Network. Questions focused on respondent characteristics, method of recognition of hypotension, triggers for initiation of vasopressor therapy, first- and second-line vasopressor choice, and methods of determining response to therapy. A total of 734 DACVECCs were invited to participate, and 203 Diplomates (27.7%) completed the survey. For both dogs and cats, the most common first-line vasopressor was norepinephrine (87.9% in dogs and 83.1% in cats). The most common second-choice vasopressor was vasopressin (44.2% in dogs and 39.0% in cats). Cutoff values for initiating vasopressor therapy varied between species and modality used for blood pressure measurement. In general, most DACVECCs chose to initiate vasopressor therapy at a Doppler blood pressure <90mmHg or a mean arterial pressure of <60 or <65mmHg when using oscillometric or direct arterial blood pressure measurements in dogs and cats. Most DACVECCs adhere to published human guidelines when choosing a first-line vasopressor. However, there is significant variability in blood pressure measurement technique, cutoffs for initiation of vasopressor use, and choice of second-line vasopressors.

Gaps in Hypertension Management in a Middle-Income Community of Quito-Ecuador: A Population-Based Study.

Optimal hypertension care and control at population level significantly reduces cardiovascular morbidity and mortality. The study objective was to measure the gaps in the diagnosis, care, and control of hypertension in residents of an urban community in Quito, Ecuador. A cross-sectional population-based study with a sample of 2160 persons was performed using a survey and direct blood pressure measurement. Logistical regression models were used for analyzing factors associated with the gaps, expressed as percentages. The prevalence of hypertension was 17.6% [CI 95% 17.3–17.9%]. The diagnosis gap was 6.1% [CI 95% 5.9–6.2%] among the entire population and 34.5% [CI 95% 33.7–35.3%] among persons with hypertension. No access gaps were detected; whereas the follow-up gap was 22.7% [CI 95% 21.8–23.6%] and control gap reached 43.5% [CI 95% 42.6–44.2%]. Results indicated that being male, older than 64 years, an employee, without health insurance, and not perceiving a need for healthcare, increased the risk of experiencing these gaps. Data showed appropriate access to health services and high coverage in the diagnosis was due to the application of a community and family healthcare model. Notwithstanding, we found significant gaps in the follow-up and control of hypertensive patients, especially among older males, which should warrant the attention of the Ministry of Health.

Agreement between oscillometric and direct blood pressure measurements in anesthetized captive chimpanzees (Pan troglodytes).

To evaluate the level of agreement (LOA) between direct and oscillometric blood pressure (BP) measurements and the ability of oscillometric measurements to accurately detect hypotension in anesthetized chimpanzees (Pan troglodytes). 8 captive, adult chimpanzees. During prescheduled annual examinations, each chimpanzee underwent general anesthesia and patient monitoring for their examination, echocardiography for a concurrent study, and measurement of direct BP with the use of tibial artery catheterization and oscillometry with the use of a cuff placed around a brachium and a cuff placed around the second digit of the contralateral forelimb for the present study. Bland-Altman plots were generated to compare results for direct and oscillometric BP measurements. Mean bias and 95% LOAs were calculated for oscillometric measurements of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) for each cuff site. Sensitivity and specificity in detecting hypotension were also determined for each cuff site. There were 74 paired direct and brachial oscillometric measurements of each, SAP, MAP, and DAP and 66 paired direct and digit oscillometric measurements of each, SAP, MAP, and DAP. Only brachial oscillometric measurements of MAP had adequate sensitivity (78%) and specificity (95%) to accurately detect hypotension, and this technique also had the least mean bias (0.8 mm Hg; 95% LOA, -29 to 31 mm Hg). Results indicated that brachial oscillometric measurement of MAP provided reasonable agreement with tibial arterial direct MAP measurement and performed well in diagnosing hypotension in anesthetized chimpanzees.

Depression of Non-Neuronal Cholinergic System May Play a Role in Co-Occurrence of Subjective Daytime Sleepiness and Hypertension in Patients with Obstructive Sleep Apnea Syndrome.

PurposeSimultaneous occurrence of hypertension and excessive daytime sleepiness (EDS) is very common in obstructive sleep apnea syndrome (OSAS), although no study has specifically addressed this issue. The present study explored the risk factors for co-occurrence of OSAS-related EDS and hypertension.Patients and MethodsA total of 161 OSAS patients were studied after undergoing an eight-hour in-laboratory polysomnography for one night. The OSAS severity assessment depends on the number of breathing disturbances per hour of sleep. EDS was defined using the Epworth Sleepiness Scale (ESS) scores of ≥13. Hypertension was defined according to direct cuff blood pressure (BP) measurements. Beat-to-beat R-R interval data were incorporated in polysomnography for heart rate variability analysis. The low-frequency/high-frequency band ratio was used to reflect sympathovagal balance. The study participants were divided into four groups based on the presence of EDS and/or hypertension: EDS with hypertension (n = 53), EDS without hypertension (n = 27), no EDS with hypertension (n = 38), and no EDS or hypertension (n = 43). Clinical, polysomnographic and heart rate data were compared and studied among the four groups. Plasma acetylcholine (ACh) levels were assessed to explore the effects of the non-neuronal cholinergic system and the co-occurrence of EDS and hypertension.ResultsPatients with EDS and hypertension had more severe OSAS severity indices compared to control patients. Increased cardiac sympathovagal imbalance and nocturnal hypoxemia regulated the presence of EDS and hypertension. Further plasma biomarker analysis revealed that both ESS scores and BP levels were associated with significantly elevated plasma norepinephrine, interleukin-6 and superoxide dismutase levels and significantly decreased ACh levels. Logistic regression analyses showed that ACh was the only factor significantly associated with co-occurrence of EDS and hypertension after controlling for confounders using odds ratio of 0.932, with a 95% confidence interval of 0.868 to 1.000 (P = 0.049).ConclusionThe results suggested that OSAS coupled with both EDS and hypertension is a more severe phenotype of the respiratory disorder. The presence of EDS and hypertension was accompanied by sympathovagal imbalance, and co-occurrence of these two conditions may be related to decreased plasma ACh levels.

THE USE OF EPHEDRINE TO TREAT ANESTHESIA-ASSOCIATED HYPOTENSION IN PINNIPEDS

Hypotension is a common adverse effect of general anesthesia that has historically been difficult to measure in pinniped species due to technical challenges. A retrospective case review found seven pinniped cases that demonstrated anesthesia-associated hypotension diagnosed by direct blood pressure measurements during general anesthesia at The Marine Mammal Center (Sausalito, CA) between 2017 and 2019. Cases included five California sea lions (CSL: Zalophus californianus), one Hawaiian monk seal (HMS: Neomonachus schauinslandi), and one northern elephant seal (NES: Mirounga angustirostris). Patients were induced using injectable opioids, benzodiazepines, and anesthetics including propofol and alfaxalone. Excluding the HMS, all patients required supplemental isoflurane with a mask to achieve an anesthetic plane allowing for intubation. Each patient was maintained with inhalant isoflurane in oxygen for the duration of the anesthetic event. Each patient was concurrently administered continuous IV fluids and four patients received fluid boluses prior to administration of ephedrine. All hypotensive anesthetized patients were treated with IV ephedrine (0.05-0.2 mg/kg). The average initial systolic (SAP) and mean (MAP) arterial blood pressures for the CSL prior to ephedrine administration were 71 ± 14 mmHg and 48 ± 12 mmHg respectively. The average SAP and MAP for the CSL increased to 119 ± 32 mmHg and 90 ± 34 mmHg respectively within 5 m of ephedrine administration. The NES initial blood pressure measurement was 59/43 (50) (SAP/diastolic [MAP]) mmHg and increased to 80/51 (62) mmHg within 5 m. The initial HMS blood pressure was 79/68 (73) mmHg and increased to 99/78 (85) mmHg within 5 m following ephedrine administration. All patients recovered from anesthesia. These results support the efficacy of IV ephedrine for the treatment of anesthesia-associated hypotension in pinnipeds.

Abstract 59: Vascular Glucagon-like Peptide 1 (GLP-1) Signaling Is Reduced In Obesity-related Hypertension In Female Rats

Obesity is a major risk factor for hypertension. Obesity-related hypertension impacts more women than men, but the underlying mechanisms remain unclear. GLP-1, an incretin released after food intake, exerts vasculo-protective effects. Human studies have shown that GLP-1 levels are decreased in obese patients. We hypothesized that vascular GLP-1 signaling is reduced in obesity and weight loss rescues this signaling. Eight-week-old female Wistar rats were randomized into three groups: LEAN (n=9) received a chow diet (5% fat, 48.7% carbohydrate [3.2% sucrose], 24.1% protein) for 28 weeks, OBESE (n=7) received a Western diet (21% fat, 50% carbohydrate [34% sucrose], 20% protein) for 28 weeks, and reverse obese (rOBESE) (n=7) received a Western diet for 18 weeks followed by 12 weeks of chow diet. The OBESE group exhibited increased body weight (395.6 vs. 285.4g LEAN, p&lt;0.0001) and body mass index (6.8 vs. 5.1kg/m 2 LEAN, p&lt;0.01), while the rOBESE group lost weight (337.0 vs. 395.6g OBESE, p&lt;0.01). Direct measurement of blood pressure (BP) using a pressure-volume catheter inserted in the carotid artery revealed increased systolic (142.8 vs. 117.2mmHg LEAN, p&lt;0.001), diastolic (125.0 vs. 92.7mmHg LEAN, p&lt;0.001), and mean arterial BP (130.9 vs. 107.9mmHg LEAN, p&lt;0.001) in the OBESE group. The rOBESE group sustained elevated systolic BP (139.1 vs.117.2mmHg LEAN, p&lt;0.05). Endothelium-dependent vasodilation studies assessed by wire myograph demonstrated that the OBESE group exhibited impaired response to acetylcholine (Emax: 82.7% vs. 97.9% LEAN, p&lt;0.001). Similar vascular impairment was observed in the rOBESE group (EMax: 81.3% vs 97.9% LEAN, p&lt;0.001). Strikingly, while decreased GLP-1 serum levels in the OBESE group (10.6 vs. 18.4pM/mL LEAN, p&lt;0.05) returned to normal levels in the rOBESE group (19.4 vs.18.4pM/mL LEAN), GLP-1 receptor protein expression was reduced in both groups (24% decrease in OBESE, 52% decrease in rOBESE) as compared to LEAN. Our results support that GLP-1 signaling is implicated in obesity-related vascular dysfunction in females and weight loss does not guarantee recovery of protective GLP-1 signaling nor improvement of vasodilation. Conclusion: GLP-1 is a potential therapeutic target for obesity-related hypertension in females.