Continuous Intra-arterial Blood Pressure Monitoring Research Articles

Continuous Intra-Arterial Blood Pressure Monitoring Improves the Efficiency of Percutaneous Balloon Compression of the Trigeminal Ganglion for Trigeminal Neuralgia.

Objective The aim of the study is to explore the characteristics of systolic blood pressure (SBP) and heart rate (HR) changes in patients undergoing percutaneous balloon compression (PBC) for trigeminal neuralgia and analyze the factors that influence the formation of the symbolic pear shape of the balloon, which signifies successful compression. Methods We retrospectively analyzed the changes in systolic blood pressure (SBP) and heart rate (HR) in 103 consecutive patients with trigeminal neuralgia (TN). Fifty-five patients who underwent operations with intermittent inflating cuff blood pressure (IICBP) monitoring were classified into the IICBP group. The other 48 patients who underwent continuous intra-arterial blood pressure (CIABP) monitoring were classified into the CIABP group. Results Among all the patients, there were more women than men and the patients in both the groups more commonly had TN on the right side and involving branch III. First, the balloon appeared as “pear-shaped” when the compression was effective, and the SBP increased an average of 59.04% in the CIABP group. CIABP provided us the precise range of the increase. Older patients had higher SBPs, especially patients with hypertension. Second, SBP was more sensitive and lasted much longer than HR in the process of puncturing the foramen ovale and compressing the ganglion. SBP fluctuated much more in the CIABP group than in the IICBP group. Third, the median time taken in the CIABP group was less than the IICBP group, and the prognosis of the CIABP group was better than the IICBP group. Conclusion Effective ganglion compression significantly increased SBP. CIABP can monitor SBP in real time and can also safeguard the compression process. CIABP is a safe and effective method in the PBC process that is worthy of promotion and application.

Microwave Ablation of Adrenal Tumors in Patients With Continuous Intra-Arterial Blood Pressure Monitoring Without Prior Alpha-Adrenergic Blockade: Safety and Efficacy.

Evaluate the safety and efficacy of adrenal microwave ablation performed with continuous intra-arterial blood pressure monitoring (IABPM) and without alpha-adrenergic blockade (AAB) as pretreatment. A single-center, retrospective review of all percutaneous adrenal microwave ablation performed between 2011 and 2018. Microwave ablation was completed on 11 patients, with a total of 15 adrenal tumors with a mean size of 3.3cm (1.4-6.9cm) treated metastatic RCC, HCC, esophageal carcinoma, adrenal adenoma. Cases were performed without prior AAB, but with continuous IABPM and rapid intervention using short-acting antihypertensive medications. There were no post-procedural episodes of hypertension, no neurological or cardiovascular complications, and no SIR moderate or worse adverse event complications. Mean intraprocedural maximum systolic blood pressure (SBP) was 211mmHg (range: 132-288), with an average increase in SBP of 100mmHg (range: 23-180). A hypertensive crisis (SBP ≥ 180 and/or DBP ≥ 120) occurred in 9 of the 15 procedures (60%) with a mean length of 3.0min (range: 1-12). The technical success rate was 100% (15/15 procedures). The mean follow-up time was 2.4years (range: 0.9-7.7years), with primary and secondary efficacy rates of 77% and 87%, respectively, and an overall survival of 82%. In this single-center retrospective study, microwave ablation of adrenal tumors without AAB was safe and effective when performed with continuous arterial line monitoring of vital signs and the use of short-acting, rapid-onset antihypertensive medications. Level 4, Case Series.

SAT-057 Endoplasmic Reticulum Aminopeptidase-1 Is a Novel Regulator of the Renin-Angiotensin-Aldosterone System and Blood Pressure Homeostasis

Endoplasmic Reticulum Aminopeptidase-1 (ERAP1) has been proposed to metabolize angiotensin II (ANGII), an effector molecule of the renin-ANGII-aldosterone (ALDO) system (RAAS) and key regulator of volume and blood pressure (BP) homeostasis. ERAP1 plays an important role in immune function as it cleaves cytokine cell surface receptors and HLA binding precursors thereby modulating their inclusion into major histocompatibility complex-I (MHC). Indeed, absence of ERAP1 in vivo shows MHC-I peptide presentation defects and decreased T regulatory cells in mice. However, the interaction between ERAP1 and RAAS remains unclear. We hypothesized that ERAP1 mediates the interaction between BP homeostasis and cardiorenal disease. We studied ERAP1 deficient heterozygous (ERAP1+/-) mice; a mouse with a phenotype likely more equivalent to what would be seen in human subjects, i.e. reduced, not absent, ERAP1. We observed that ERAP1+/- mice had 45% lower ERAP1 levels by western blot analyses in heart and kidney as compared to wild-type (WT) littermate control mice maintained on regular rodent chow (n= 10 of each type, p=0.029). We measured ANGII tissue levels by LC/MS and show increased levels in heart, kidney and aortas from ERAP1+/- as compared to WT control mice (P<0.05). On regular rodent chow, urinary 24 hr ALDO levels were increased in ERAP1+/- compared to WT mice (7.11 ±0.82 [WT, n=10] vs 9.92 ±0.88 ng/dL [ERAP1+/-, n=8], p=0.03) while plasma renin activity (PRA) were not significantly different between the two mouse types (65.3±3.2 [WT, n=10] vs 66.16±2.3 ng/ml*h [ERAP1+/-, n=8]). We also evaluated BP by tail cuff on mice maintained on regular rodent chow and showed increased systolic BP in ERAP1+/- as compared to WT mice, (122.8±0.8 [ERAP1, n=9] vs. 110.2±1.6 mmHg [WT, n=12], p=0.003). We then studied the effects of salt intake on BP in these mice. ERAP1+/- mice had increased salt sensitivity of BP, defined as systolic BP on high, 1.6% Na+ diet minus systolic BP on low, 0.03% Na+ diet, when compared to WT mice (SSBP: 8.5±2.3 [ERAP1, n=15] vs -0.2 ±1.6 mmHg [WT, n=15], p=0.0043). Similar results were obtained using continuous intraarterial BP monitoring by telemetry in freely moving mice (SSBP by telemetry: 6.8±1.2 [ERAP1, n=3] vs 0.4±0.7 mmHg [WT, n=2], p<0.001). We then studied renal hemodynamics using 2D and Color-Doppler imaging and showed that ERAP1+/- mice have increased peak-systolic velocity (PSV) and end-diastolic velocity (EDV) compared to WT mice on regular mouse chow (PSV: 412.6±38.6 [WT, n=4] vs 570.2±27.7 mm/s [ERAP1+/-, n=3] p=0.027; EDV: 127.9±9.8 [WT, n=4] vs 191.0±16.3 mm/s [ERAP1+/-, n=6], p=0.02). In conclusion, ERAP1 deficiency is associated with SSBP, likely secondary both to increased ALDO and altered renovascular function.

Invasive versus non-invasive monitoring of acute severe hypertension in women with pre-eclampsia

ObjectiveTo compare the accuracy of two non-invasive methods of blood-pressure measurement with intra-arterial measurement in women with pre-eclampsia and acute severe hypertension. MethodsThis descriptive, cross-sectional study prospectively enrolled 23 women with pre-eclampsia and acute severe hypertension for continuous intra-arterial blood-pressure monitoring. Simultaneous monitoring was performed with a manual and an automated, non-invasive device during episodes of severe hypertension. The paired T-test was used to compare measured values. The accuracy of a MAP⩾125mmHg in detecting a systolic blood pressure⩾160mmHg was determined. ResultsThere was a weak correlation between intra-arterial and automated as well as intra-arterial and manual systolic values (r=0.34, p<0.01; r=0.41, p<0.00, respectively). Better correlation was found amongst diastolic values. The differences between the mean intra-arterial (94±11mmHg) and automated (96±12mmHg) diastolic values as well as intra-arterial and manual diastolic measurements (94±14mmHg) were not significant (p=0.20, 0.65, respectively). A mean arterial pressure⩾125mmHg was not accurate in detecting a systolic value⩾160mmHg, with low sensitivities (17.2–35.9%) and specificities (0–50%) for all three methods. ConclusionsWhen compared to intra-arterial monitoring, the automated and manual methods showed weak correlation with systolic but better correlation with diastolic values. A mean arterial pressure⩾125mmHg was not accurate in detecting systolic peaks. When protection against cerebral haemorrhage is paramount, intra-arterial measurement of systolic values is best.

A Comparison of Radial Artery Blood Pressure Determination Between the Vasotrac Device and Invasive Arterial Blood Pressure Monitoring in Adolescents Undergoing Scoliosis Surgery

The Vasotrac device (Medwave, Arden Hills, MN) allows noninvasive measurement of arterial blood pressure (BP) and arterial waveform. We have previously demonstrated agreement between the Vasotrac and continuous intraarterial BP monitoring in children with a stable circulation after cardiac surgery in the cardiac intensive care unit. To assess this monitor during different physiologic conditions, we studied the Vasotrac in anesthetized adolescent children undergoing scoliosis surgery in the prone position, with or without controlled hypotension. Eleven children undergoing surgery for idiopathic scoliosis were enrolled in this study. The anesthetic consisted of primarily a nitrous oxide and narcotic technique with controlled hypotension obtained using IV labetalol. Data were analyzed using correlations, mean error, and Bland-Altman plots. Noninvasive BP measured by the Vasotrac correlated closely with intraarterial BP. Waveforms displayed by the two systems were qualitatively similar. Correlation between the two methods for systolic, diastolic and mean BP was r = 0.82, r = 0.83, and r = 0.90, respectively. We conclude that noninvasive BP measurement using the Vasotrac monitor enables near-continuous and reliable monitoring of BP during anesthesia in the prone position and pharmacologic-induced hypotension. The Vasotrac, a noninvasive arterial blood pressure monitor, performs well in the prone position in adolescent patients undergoing scoliosis surgery using a technique of mild-to-moderate induced hypotension.

Significance of clinical risk factors of cystic periventricular leukomalacia in infants with different birthweights

Fifteen appropriate-for-date premature low-birthweight infants with cystic periventricular leukomalacia (PVL) were studied. The infants were stratified into three birthweight groups: less than 1000 g, 1000 g and greater but less than 1500 g, and 1500 g or greater. Reported and new risk factors for PVL were compared with control patients for all patients and each birthweight group. Hypocarbia was significantly related to cystic PVL, especially in infants with birthweight 1000 g or greater (p < 0.03). Sensitivity to hypocarbia might be decreased in infants with birthweight less than 1000 g due to therapy or prematurity. In the group with birthweight less than 1000 g, the proportion of cystic PVL infants on continuous intra-arterial blood-pressure monitoring tended to be lower than the controls, with an almost significant difference (p= 0.05). The duration of tocolysis was significantly longer in the cystic PVL infants than in the controls when the birthweight was greater than 1500 g (p < 0.04). For some risk factors, a significant difference or a tendency of difference was demonstrated only after stratifying the birthweight. For others, the difference became insignificant after stratification. Assessing risk factors after stratifying by birthweight or degree of prematurity is therefore useful. Conclusion: The results suggest that hypocarbia should be avoided to prevent cystic PVL, especially in infants with birthweight of 1000 g or greater, continuous intra-arterial blood-pressure monitoring may be important in infants with birthweight less than 1000 g, and fetal status should be monitored carefully when the duration of tocolysis is prolonged, especially in infants with birthweight of 1500 g or more.

Significance of clinical risk factors of cystic periventricular leukomalacia in infants with different birthweights

Fifteen appropriate-for-date premature low-birthweight infants with cystic periventricular leukomalacia (PVL) were studied. The infants were stratified into three birthweight groups: less than 1000 g, 1000 g and greater but less than 1500 g, and 1500 g or greater. Reported and new risk factors for PVL were compared with control patients for all patients and each birthweight group. Hypocarbia was significantly related to cystic PVL, especially in infants with birthweight 1000 g or greater (p < 0.03). Sensitivity to hypocarbia might be decreased in infants with birthweight less than 1000 g due to therapy or prematurity. In the group with birthweight less than 1000 g, the proportion of cystic PVL infants on continuous intra-arterial blood-pressure monitoring tended to be lower than the controls, with an almost significant difference (p = 0.05). The duration of tocolysis was significantly longer in the cystic PVL infants than in the controls when the birthweight was greater than 1500 g (p < 0.04). For some risk factors, a significant difference or a tendency of difference was demonstrated only after stratifying the birthweight. For others, the difference became insignificant after stratification. Assessing risk factors after stratifying by birthweight or degree of prematurity is therefore useful. The results suggest that hypocarbia should be avoided to prevent cystic PVL, especially in infants with birthweight of 1000 g or greater, continuous intra-arterial blood-pressure monitoring may be important in infants with birthweight less than 1000 g, and fetal status should be monitored carefully when the duration of tocolysis is prolonged, especially in infants with birthweight of 1500 g or more.

Influence of age on the cardiovascular response during graded haemorrhage in anaesthetized rats.

The present study was designed to follow the cardiovascular response to graded haemorrhage in two groups of adult rats of different ages. Group A (n = 10) had a mean body weight (bwt) of 655 g (50 weeks old) and group B (n = 10) had a mean bwt of 250 g (12 weeks old). After induction of anaesthesia, the carotid artery was cannulated for continuous intra-arterial blood pressure monitoring and for controlled haemorrhage. Five per cent of the total blood volume (TBV) was removed every 15 min until a maximum of 50% was reached. Mean arterial pressure (MAP) fell by 4-9 mm Hg each time 5% TBV was removed in both groups, and at the end of the study the MAP was comparable in the two groups (34 +/- 10 mm Hg in group A and 28 +/- 8 mm Hg in group B). There were no significant changes in heart rate (HR) in the young animals during haemorrhage, while there was a significant drop in heart rate in the older animals when blood loss exceeded 15% of TBV (P < 0.05). A significant difference was also observed in HR between the two groups of animals with blood loss in excess of 20% TBV (P < 0.05). It was concluded that although the hypotension induced by graded haemorrhage was similar in young and old rats, the older animals were less able to maintain their HR, probably as a consequence of age- and anaesthetic-related changes in sympathetic activity.

24-Hour Blood Pressure Control with the Once-Daily Calcium Antagonist Amlodipine

The efficacy and toleration of once-daily amlodipine (5-10 mg) was studied in 11 patients with mild to moderate hypertension. Continuous intra-arterial blood pressure monitoring was used to study the effects of amlodipine over a 24-h period. Following a 2-week placebo run-in period, amlodipine was given initially as a single-blind 5-mg dose for 2 weeks and increased to 10 mg if required to control blood pressure for a further 4 weeks. Twenty-four-hour intra-arterial blood pressure recordings made after 6 weeks of treatment with amlodipine revealed that amlodipine effectively reduced blood pressure throughout the whole 24-h period without altering the normal circadian pattern. The mean daytime blood pressure was reduced from 165/103 to 147/89 mm Hg (p < 0.05) and the mean nighttime blood pressure was reduced from 137/79 to 121/69 mm Hg (p < 0.05). There was no significant change in heart rate. The mean supine blood pressure measured sphygmomanometrically was reduced from 169/103 mm Hg after placebo to 153/98 mm Hg after 2 weeks of treatment and to 145/92 mm Hg at the end of the study. The results of isometric and dynamic exercise testing showed that amlodipine decreased blood pressure, with no postural decrease on tilting and no change in the proportional increase in blood pressure at peak exercise. Amlodipine was well tolerated although one patient developed ankle edema that would have required discontinuation had she not already completed the study. This study has shown that amlodipine effectively reduced blood pressure for 24 h after once-daily dosing and was well tolerated.

Evaluation of the Efficacy of Slow-Release Nifedipine in Systemic Hypertension by Ambulatory Intraarterial Blood Pressure Monitoring

We assessed the effect on blood pressure of administration of slow-release nifedipine tablets (20 mg) by continuous intraarterial blood pressure monitoring (Oxford system) in 10 patients with untreated essential hypertension. Blood pressure was recorded under control conditions and during nifedipine therapy. During each monitoring period patients were instructed to perform various types of exercise. The initial dose of nifedipine was 20 mg twice a day (8:00 a.m. and 8:00 p.m.). For patients in whom arterial pressure control was not achieved, the dose of the drug was increased at weekly intervals, first to 40 mg in the morning and 20 mg at night and then to 40 mg twice a day. The average daily dose was 52 mg. Nifedipine twice a day significantly reduced systolic and diastolic blood pressures both during the day and during the night. The rise in blood pressure due to dynamic or isometric exercise or to mental testing was blunted. Heart rate did not change. Orthostatic hypotension was not observed, and there were only minor side effects, which did not require withdrawal of the patient from the trial. Bioavailability of nifedipine from this preparation was satisfactory, as shown by plasma concentrations which remained constantly in the therapeutic range. Thus, slow-release nifedipine given twice a day represents an effective treatment in patients with essential arterial hypertension. The reduced frequency of administration required may improve patient compliance with this treatment.