Beat-to-beat agreement of non-invasive finger artery and invasive radial artery blood pressure in hypertensive patients taking cardiovascular medication

Summary. The aim of this study was to investigate and quantify the agreement between simultaneous and ipsilateral non-invasive finger artery blood pressure (Finapres®) and intra-arterial radial blood pressure among 13 volunteer hypertensive patients, aged 36–71 years and taking cardiovascular medication, during steady-state fluctuation of arterial blood pressure and during an increase in blood pressure induced by static exercise. Eight patients were being treated with beta-blocking agents, eight with calcium antagonists, four with angiotensin-converting enzyme inhibitors, four with diuretics and one with prazosin in combination therapy. Their auscultatory brachial artery blood pressures ranged in systole from 142 to 206 mmHg and in diastole from 88 to 120 mmHg during the treatment. The mean systolic finger artery blood pressure deviated by -14±5 mmHg (P=0.02, mean value±SEM) and the diastolic finger artery blood pressure deviated by 0.6±3 mmHg (P=0.70) from the corresponding radial artery pressure. The maximal beat-to-beat difference between systolic and diastolic finger and radial artery pressure, respectively, showed that a range of less than 10 mmHg in the steady state after individual adjustment for bias. In general, neither systolic nor diastolic differences between the methods exceeded the limits of ±10 mmHg, and the bias did not significantly increase (P≥0.12) during a 10-mmHg increase in arterial blood pressure caused by static exercise. Among three subjects, an increase in bias and poorer agreement was associated with atrial fibrillation and steplike changes in the Finapres output after autocalibration. The results support usage of the Finapres technique to measure beat-to-beat changes of peripheral arterial blood pressure in hypertensive patients taking cardiovascular medication, with a feasible agreement with beat-to-beat radial artery blood pressure.     

Non-invasive vs. invasive beat-to-beat monitoring of blood pressure

Summary. The present study focuses on the accuracy in tracing fast beat-to-beat changes in blood pressure using a non-invasive technique. The measurements using a commercially available apparatus (Finapres, Ohmeda, USA) were compared to ipsilateral intra-arterial radial pressure. Eight patients were studied at rest, during deep breathing with a fixed rate of 6 breaths min^-1, and during an exercise test on an ergometer cycle. A total of 900 systolic pressure values were included for statistical evaluation, covering a pressure range of 86–266 mmHg. On average the systolic correlation coefficient for the whole material was 0.97, with a range of 0.94–0.996. For mean pressure the correlation coefficient was on average 0.97, and for diastolic pressure 0.93. No systematic difference between the non-invasive and the invasive method was found, although for each individual patient a difference between direct and indirect measured blood pressure existed that could be relatively large (systolic pressure: average difference = 0.8 mmHg, SD = 16 mmHg). We found the method easy to handle and consider it excellently suited to track relative changes in blood pressure.     

Comparative accuracies of a finger blood pressure monitor and an oscillometric blood pressure monitor

A noninvasive blood pressure monitor (Finapres) that uses the methodology of Peaz to continuously display the arterial waveform from the finger has been introduced recently. The Finapres monitor overestimated systolic pressure by 5.8±11.9 mm Hg, while the Dinamap monitor underestimated systolic pressure by –6.9±9.2 mm Hg (P=0.003). Dinamap mean and diastolic pressure biases were less than 2 mm Hg, while the Finapres biases for these variables were significantly greater (7.7±10.0 and 8.2±9.8 mm Hg, respectively). There was no difference in systolic or mean pressure precision between the two devices (approximately 10 mm Hg), but the diastolic precision of the Dinamap unit was superior to that of the Finapres. While in most patients the Finapres monitor provided continuous blood pressure data equivalent to the data from the radial artery, marked bias (>15 mm Hg) was exhibited in 2 patients for all three pressure variables. Despite this bias, blood pressure changes were tracked closely in these 2 patients. We conclude that, in its current form, the Finapres monitor cannot be relied upon independently to accurately measure blood pressure in patients undergoing general anesthesia. Since the Dinamap monitor measures mean pressure reliably and accurately, we suggest that mean blood pressure values between the Finapres and Dinamap monitors be compared to guide one in interpreting Finapres data.Supported in part by a grant from Ohmeda Company, Boulder, CO.Presented in part at the annual meeting of the American Society of Anesthesiologists, New Orleans, October 1989.     

Comparative accuracies of a finger blood pressure monitor and an oscillometric blood pressure monitor

A noninvasive blood pressure monitor (Finapres) that uses the methodology of Peňaz to continuously display the arterial waveform from the finger has been introduced recently. The Finapres monitor overestimated systolic pressure by 5.8±11.9 mm Hg, while the Dinamap monitor underestimated systolic pressure by ?6.9±9.2 mm Hg (P=0.003). Dinamap mean and diastolic pressure biases were less than 2 mm Hg, while the Finapres biases for these variables were significantly greater (7.7±10.0 and 8.2±9.8 mm Hg, respectively). There was no difference in systolic or mean pressure precision between the two devices (approximately 10 mm Hg), but the diastolic precision of the Dinamap unit was superior to that of the Finapres. While in most patients the Finapres monitor provided continuous blood pressure data equivalent to the data from the radial artery, marked bias (>15 mm Hg) was exhibited in 2 patients for all three pressure variables. Despite this bias, blood pressure changes were tracked closely in these 2 patients. We conclude that, in its current form, the Finapres monitor cannot be relied upon independently to accurately measure blood pressure in patients undergoing general anesthesia. Since the Dinamap monitor measures mean pressure reliably and accurately, we suggest that mean blood pressure values between the Finapres and Dinamap monitors be compared to guide one in interpreting Finapres data.     

Effect of temperature on finger artery pressure evaluated by volume clamp technique

Summary. We examined the effect of temperature on digital arterial blood pressure obtained by continuous beat-to-beat non-invasive monitoring with a volume-clamp technique (Finapres). In 10 normal volunteers and 13 patients with symptoms of vasospasm, digital pressure and brachial artery pressure (cuff method) was simultaneously recorded in control conditions at room temperature, during body cooling, finger heating, and truncal heating. In the control condition digital systolic blood pressure was significantly higher (16.1 14.2 mmHg) than brachial systolic pressure. The augmentation of digital systolic pressure correlated inversely with finger tip temperature. Diastolic and mean arterial pressure did not differ significantly between the two methods. Body cooling augmented the systolic finger-arm gradient while truncal heating and finger heating had the opposite effect. Finger heating reduced systolic augmentation without changing the mean and diastolic blood pressure. Similar changes were also observed in the patients with vasospasm except in one case with a pronounced Raynaud syndrome where digital blood pressure was lower than brachial artery pressure. We conclude that augmentation of finger systolic pressure seems to be dependent on local vasoconstriction of A/V shunts and that finger heating may be a useful procedure to improve the reliability of Finapres readings.,     

In aged men,central vessel transmural pressure is reduced by brief Valsalva manoeuvre during strength exercise

A brief Valsalva manoeuvre, lasting 2–3 s, performed by young healthy men during strength exercise reduces transmural pressure acting on intrathoracic arteries. In this study, we sought to verify this finding in older men. Twenty normotensive, prehypertensive and moderately hypertensive otherwise healthy men 46–69 years old performed knee extensions combined with inspiration or with brief Valsalva manoeuvre performed at 10, 20 and 40 mmHg mouth pressure. Same respiratory manoeuvres were also performed at rest. Non‐invasively measured blood pressure, knee angle, respiratory airflow and mouth pressure were continuously registered. In comparison to inspiration, estimated transmural pressure acting on thoracic arteries changed slightly and insignificantly during brief Valsalva manoeuvre at 10 and 20 mmHg mouth pressure. At 40 mmHg mouth pressure, transmural pressure declined at rest (?8·8 ± 11·4 mmHg) and during knee extension (?12·1 ± 11·9 mmHg). This decline ensued, as peak systolic pressure increase caused by this manoeuvre, was distinctly <40 mmHg. Only a main effect of mouth pressure was revealed (P<0·001) and neither exercise nor interaction between these factors, what suggests that transmural pressure decline, depended mainly on intrathoracic pressure developed during brief Valsalva manoeuvre. Resting blood pressure did not influence the effect of brief Valsalva manoeuvre on transmural pressure.     

102例危重病患者有创血压和无创血压的对比

目的比较102例危重病患者有创血压（IBP）和无创血压（NBP）测量结果的一致性。 方法收集2016年3~9月在西安交通大学第二附属医院重症医学科住院治疗的102例危重病患者的尺/桡动脉IBP和同侧上臂NBP数据1072对,先对所有数据分别按收缩压、舒张压、脉压（PP）和平均动脉压（MAP）进行配对t检验;再将数据分为高血压组（MAP≥107 mmHg）（1 mmHg=0.133 kPa）、正常血压组（70 mmHg≤MAP<107 mmHg）和低血压组（MAP<70 mmHg）三个亚组,分别进行IBP和NBP的收缩压、舒张压、PP以及MAP间的配对t检验。以P<0.05为差异具有统计学意义。 结果有创收缩压和无创收缩压之间比较,差异具有统计学意义［（128.08±35.48）mmHg vs（122.56±24.84）mmHg,t=7.896,P<0.001）］;有创舒张压和无创舒张压之间比较,差异具有统计学意义［（65.66±13.69）mmHg vs（67.98±13.31）mmHg,t=-8.294,P<0.001］;有创PP和无创PP之间比较,差异具有统计学意义［（62.42±28.93）mmHg vs（54.58±20.00）mmHg,t=11.697,P<0.001］;有创MAP和无创MAP之间比较,差异无统计学意义［（86.47±18.94）mmHg vs（86.17±15.33）mmHg,t=0.867,P=0.386］。亚组分析显示高血压组（n=254）：有创收缩压和无创收缩压之间比较,差异具有统计学意义［（163.75±33.93）mmHg vs（152.16±16.78）mmHg,t=6.52,P<0.001］,有创舒张压和无创舒张压之间比较,差异具有统计学意义［（79.17±11.03）mmHg vs（83.69±9.50）mmHg,t=-6.85,P<0.001）］,有创PP和无创PP之间比较,差异具有统计学意义［（84.57±31.50）mmHg vs （68.47±20.72）mmHg,t=9.76,P<0.001］;正常血压组（n=687）：有创收缩压和无创收缩压之间比较,差异具有统计学意义［（122.66±24.74）mmHg vs（118.70±15.14）mmHg,t=5.071,P<0.001）］,有创舒张压和无创舒张压之间比较,差异具有统计学意义［（63.97±10.34）mmHg vs（65.60±8.49）mmHg,t=-5.049,P<0.001）］,有创PP和无创PP之间比较,差异具有统计学意义［（58.69±23.05）mmHg vs （53.10±11.90）mmHg,t=7.682,P<0.001］;低血压组（n=131）：有创收缩压和无创收缩压之间比较,差异无统计学意义［（87.35±24.33）mmHg vs（85.41±11.99）mmHg,t=1.109,P=0.269］,有创舒张压和无创舒张压之间比较,差异具有统计学意义［（48.32±8.27）mmHg vs（49.98±8.06）mmHg,t=-2.073,P=0.040］,有创PP和无创PP之间比较,差异具有统计学意义［（39.03±24.00）mmHg vs（35.43±13.97）mmHg,t=1.806,P<0.001］。 结论有创收缩压大于无创收缩压、有创舒张压小于无创舒张压、有创PP大于无创PP,而有创MAP等于无创MAP。采用MAP数值较采用收缩压和（或）舒张压数值可以消除IBP和NBP测量之间的差异。     

Clinical evaluation of the Takeda Medical (A & D) TM 2420 ambulatory blood pressure monitor. Practical experience and comparison with direct and indirect measurements

Takeda Medical (A & D) TM 2420 is an automatic ambulatory blood pressure monitoring system employing the auscultatory technique. The device was used under stable conditions and compared to readings from the Hawksley randomzero sphygmomanometer using a double headset stethoscope and a Y-connection. We tested 85 subjects (aged 13–89 years, systolic blood pressure 85–212 mmHg, diastolic blood pressure 40–116 mmHg) and found a difference amounting to 1.6±6.7 mmHg (mean±SD) for systolic and 2.1±4.5 mmHg for diastolic readings (Hawksley-TM 2420). In 62 subjects a comparison with simultaneous measurement on the opposite arm with the Hawksley manometer showed similar results. When comparing intra-arterial readings from 10 subjects, a difference (intra-arterial-TM 2420) of -1.9±12.1 mmHg was found for systolic pressures, while the diastolic difference was -10.7±8.7 mmHg. Twenty-four hour monitoring was performed on 80 subjects; 70 of these yielded usable tracings. The proportion of successful recordings was acceptable, but the device was not suitable for bicycle stress testing. The quality of the accessories provided with the equipment could be improved, but in spite of this the monitoring system was found to be recommendable for clinical use.     

The relative accuracies of two automated noninvasive arterial pressure measurement devices

We compared the accuracies of two types of noninvasive blood pressure devices. Thirty-two patients requiring an intraarterial catheter for anesthetic management underwent simultaneous monitoring with Dinamap 1846SX and Ohmeda Finapres 3700 devices. For the first 10 minutes of recording, new Dinamap determinations were performed every 60 seconds; subsequent recordings were made at 3-minute intervals. Data were obtained at the time of new Dinamap readings, and twice between new readings to approximate the real-time performance of the two monitors. We defined superior accuracy as a statistically significant difference in mean absolute error greater than 5 mm Hg. With these criteria, pooled data from all patients revealed no difference in performance, even in real time. Pooled data can be misleading since there was a significant amount of variation in accuracy for both monitors. Therefore, we used nonparametric analysis to determine how many individual patients were monitored better by either device. When we compared only data from new Dinamap readings, the Finapres monitor showed superior performance for systolic readings in 13 patients, versus 6 patients for the Dinamap (P<0.05, chi-square test). Similar analysis for diastolic and mean pressure performance did not reach statistical significance. However, in real time, the Finapres unit monitored more patients more accurately for systolic (14 Finapres versus 3 Dinamap), diastolic (11 Finapres versus 3 Dinamap), and mean (10 Finapres versus 3 Dinamap) pressure determinations. The magnitude of these differences were, however, less dramatic than expected. This was probably due to stabilization of arterial pressure during the anesthetic, which minimized the error due to intermittent sampling. We conclude that continuous Finapres readings and new Dinamap determinations are equally accurate for diastolic and mean arterial pressures. The accuracy of Finapres appears to be slightly superior for systolic pressure. The intermittent sampling of oscillometric devices compromises their performance relative to the Finapres in many, but not all, cases.Presented in part at the annual meeting of the American Society of Anesthesiologists, San Francisco, Oct 1988.     

Cardiac output and blood pressure during active and passive standing

Summary. The present study compared the haemodynamic pattern of active and passive standing. We used non-invasive techniques with beat-to-beat evaluation of blood pressure, heart rate and stroke volume. Seven healthy subjects, aged 24–41 (mean 30) years were examined. Finger blood pressure was continuously recorded by volume clamp technique (Finapres ®), and simultaneous beat-to-beat beat stroke volume was obtained, using an ultrasound Doppler technique, from the product of the valvular area and the aortic flow velocity time integral in the ascending aorta from the suprasternal notch. Measurements were performed at rest, during active standing and following passive tilt (60°). Active standing caused a transient but greater reduction of blood pressure and a higher increase of heart rate than passive tilt during the first 30 s (δ mean blood pressure: -39 ± 10 vs. -16 ± 7 mmHg, δ heart rate: 35 ± 8 vs. 12 ± 7 beats m^-1 (active standing vs. passive tilt; P < 0.01). There was a significantly larger increase in cardiac output during active standing (37 ± 24 vs. 0 ± 15%, P < 0.01) and a more marked decrease in total peripheral resistance (-58 ± 11 vs. -16 ± 17%, P < 0.01). A precipitous rise in intra-abdominal pressure (43 ± 22 mmHg) could be observed upon rising only in active standing. This was interpreted as an indication of translocation of blood to the thorax. There was no significant difference in haemodynamic changes during the later stage of standing (1–7 min) between both manoeuvres. These results suggest that active standing causes a marked blood pressure reduction in the initial phase which seems to reflect systemic vasodilatation caused by activation of cardiopulmonary baroreflexes, probably due to a rapid shift of blood from the splanchnic vessels in addition to the shift from muscular vessels associated with abdominal and calf muscle contraction. Moreover, the ultrasound Doppler technique was found to be a more adequate method for rapid beat-to-beat evaluation of cardiac output during orthostatic manoeuvres.     

Factors affecting the validity of the standard blood pressure cuff,

Summary. Fifty-eight patients, 31 women and 27 men, with a wide range of upper arm circumferences (20.43 cm), ages (16.82 years) and body mass indices (16.55 kg m^?2) were studied. The direct blood pressure was measured in the brachial artery in one arm and simultaneously the indirect pressure was measured in the other arm using a large standard cuff (rubber bag 12 times 35 cm). The mean intra-arterial blood pressure was (systolic/diastolic) 13725 mmHg (SD)/7610 mmHg. With the cuff the mean blood pressure was 13423 mmHg/85ll mmHg. The cuff significantly underestimated the systolic blood pressure (3.2ll.4 mmHg, range -25–30 mmHg) while the diastolic pressure was overestimated significantly (8.88.5 mmHg, range -32.14 mmHg). The direct/indirect blood pressure difference correlated significantly to the intraarterial systolic and diastolic pressures (systolic/diastolic; r=0.44, P= 0.0006/r=0.36, P= 0.0062), but only to the auscultatory diastolic pressure (r=-0.02, P= 0.9/r= -0.45, P= 0.0004). The direct/indirect difference correlated significantly to the arm circumference (r= -0.33, P= 0.01/r= -0.30, P= 0.02) as did the diastolic direct/indirect difference to pulse rate (r= 0.34, P= 0.009). Age did not correlate significantly to the direct/indirect blood pressure difference in this study (r= -0.02, P= 0.9/r=-0.10, P= 0.5). It can be concluded that in addition to the ratio between the arm circumference and the width of the cuff (rubber bag), there are other sources of systematic errors of indirect blood pressure measurement, in particular pulse rate and the level of indirect blood pressure. If corrections could be made with regard to these variables, it is obvious that the reliability of the indirect method, especially when used in epidemiological contexts, would increase.     

Assessment of blood pressures and gradients by automated blood pressure device compared to invasive measurements in patients previously operated on for coarctation of the aorta

Summary. The aim of the study was to compare invasive and non-invasive blood pressure measurements and gradients. Twenty-two children and 16 adults previously operated for coarctation of the aorta were included. Invasive blood pressures were recorded proximally and distally close to the former operation site and non-invasive systolic blood pressures were recorded by an automated sphygmomanometer on right arm and leg. The adults were investigated at rest and during supine exercise. The correlation between invasive and non-invasive measurements of proximal blood pressures in adults at rest and children were the following, r= 0.92, SD 7.6 mmHg (n= 16) and r= 0.85, SD 11 mmHg (n= 22) respectively. The corresponding correlation for the distal blood pressures were the following for adults at rest 0.64, SD 11.9 mmHg and in children /- = 0.82, SD 9.2 mmHg. During exercise in adults we found a low correlation when comparing invasive and non-invasive proximal and distal blood pressures and a poor correlation regarding the gradients, r= 0.50, SD 16 mmHg, r= 0.45, SD 15.9 mmHg and r= 0.30, SD 22.9 mmHg respectively (n= 16). We also measured the time interval between cessation of exercise and completion of the blood pressure recordings, which gave a mean interval of 73 sec (range 45–115 sec). During that interval the mean fall in the proximal blood pressure was 37 mmHg (range 20–80 mmHg), and the mean fall of the gradient was from 41 mmHg (range 20–76 mmHg) to 23 mmHg (range 6–56 mmHg). We conclude that the non-invasive estimation of proximal blood pressures gave fair results but that the estimation of gradients are unsatisfactory. The use of this method to predict exercise induced blood pressures changes and gradients seems highly unreliable.     

A poor correlation exists between oscillometric and radial arterial blood pressure as measured by the Philips MP90 monitor

In anesthesia and critical care, invasive arterial blood pressure monitoring is the gold standard against which other methods of monitoring are compared. In this assessment of the Philips MP90 monitor, the objective was to determine whether or not oscillometric measurements were within the accuracy standards set by the Association for the Advancement of Medical Instrumentation (AAMI) and the British Hypertension Society (BHS). Three hundred and one invasive and noninvasive paired measurements were obtained from eleven adult patients on the neurosurgical service at Stanford University Medical Center. Bland–Altman plots were created to assess agreement between the two measurement systems. Paired correlation analysis, bias and precision calculations were performed. Oscillometric blood pressure measurements correlated with arterial measurements yielding Pearson r values of 0.68, 0.67 and 0.62 for systolic, diastolic and mean pressures, respectively (P < 0.01.) Mean differences with 95% confidence intervals were −3.8 mmHg ± 13.6, −2.4 mmHg ± 10.0, and 4.0 mmHg ± 13.1 for systolic, diastolic and mean pressures, respectively. The mean difference for these measurements was ≤5 mmHg as stipulated by the AAMI guidelines, but the standard deviation was greater than the 8 mmHg allowed by the AAMI guidelines. When the BHS guidelines were applied, the device merited a grade “D” for systolic and mean arterial pressure, and a grade “C” for diastolic pressure, with the highest possible grade level being “A.” There was a poor correlation between noninvasive and invasive measurements of arterial blood pressure as measured with a cuff and radial arterial cannula using the Philips MP90 monitor. These inaccuracies could lead to unnecessary interventions, or lack of appropriate interventions in anesthetic management. Further study is needed to specify the absolute inaccuracy of the monitor, and to determine if accuracy between the two methods varies with patient co-morbidities, surgical procedures, or anesthetic management. Mireles SA, Jaffe RA, Drover DR, Brock-Utne JG. A poor correlation exists between oscillometric and radial arterial blood pressure as measured by the Philips MP90 monitor.     

Comparison study of upper arm and forearm non-invasive blood pressures in adult Emergency Department patients

BackgroundForearm blood pressures have been suggested as an alternative site to measure blood pressures when the upper arm is unavailable. However there is little evidence utilising clinical populations to support this substitution.ObjectivesTo determine agreement between blood pressures measured in the left upper arm and forearm using a singular oscillometric non-invasive device in adult Emergency Department patients. The secondary objective was to explore the relationship of blood pressure differences with age, sex, ethnicity, smoking history and obesity.DesignSingle centre comparison study.SettingAdult Emergency Department, Tertiary Trauma Centre.ParticipantsForty-four participants who met inclusion/exclusion criteria selected sequentially from the Emergency Department arrival board.MethodsA random assignment of order of measurement for left upper arm and forearm blood pressures was utilised. Participants were eligible if they were aged 18 years or older, had been assigned an Australasian Triage Scale code of 2, 3, 4, or 5, were able to consent, and able to have blood pressures measured on their left arm whilst lying at a 45° angle. The Bland–Altman method of statistical analysis was used, with the level of agreement for clinical acceptability for the systolic, diastolic and mean arterial pressure defined as ±10 mmHg.ResultsThe forearm measure overestimated systolic (mean difference 2.2 mmHg, 95% limits of agreement ±19 mmHg), diastolic (mean difference 3.4 mmHg, 95% limits of agreement ±14.4 mmHg), and mean arterial pressures (mean difference 4.1 mmHg, 95% limits of agreement ±13.7 mmHg). The systolic measure was not significantly different from zero. Evidence of better agreement was found with upper arm/forearm systolic measures below 140 mmHg compared to systolic measures above 140 mmHg using the Levene's test (p = 0.002, F-statistic = 11.09). Blood pressure disparity was not associated with participant characteristics.ConclusionsForearm measures cannot routinely replace upper arm measures for blood pressure measurement. If the clinical picture requires use of forearm blood pressure, the potential variance from an upper arm measure is ±19 mmHg for systolic pressure, although the variability may be close to ±10 mmHg if the systolic blood pressure is below 140 mmHg.     

Blood pressure behaviour in chronic daily headache

The objective was to examine the association between high blood pressure (BP) and chronic daily headache using 24-h ambulatory blood pressure monitorization (24-h ABPM). This was a cross sectional study in an out-patient clinic. Women were selected among patients referred for first evaluation, 62 with chronic daily headache and 57 without chronic daily headache. The main outcome measures were mean office systolic and diastolic blood pressure (BP), mean systolic and diastolic daytime and night-time BP and BP load, and mean systolic and diastolic nocturnal fall. Office systolic BP was 138.2 mmHg for women with chronic daily headache and 141.7 mmHg for women without headache (P = 0.36). Office diastolic BP was 88.9 mmHg for women with headache and 92.7 mmHg for women without headache (P = 0.17). Mean daytime and mean night-time systolic BP was, respectively, 122.2 mmHg and 108.8 mmHg for women with headache and 122.9 mmHg and 109.5 for women without headache (P = 0.82 and P = 0.80, respectively). Mean daytime and mean night-time diastolic BP was, respectively, 78.6 mmHg and 65.4 mmHg for women with headache and 79.9 mmHg and 67.1 mmHg for the women without headache (P = 0.80 and P = 0.45, respectively). There was no difference between the two groups regarding systolic and diastolic BP load and nocturnal systolic and diastolic fall. No significant difference in BP values was observed in women with chronic daily headache compared with women without headache using 24-h ABPM.     

Validation of the new Complior sensor to record pressure signals non-invasively

The Complior device (Alam Medical, France) has contributed to the rise of arterial stiffness as a measure of cardiovascular risk. In its latest version (Complior Analyse) the sensor records pressure instead of distension waveforms thus allowing the measurement of central pressure and pulse wave analysis. The aim of our study was to verify that the new sensor measures pressure waveforms accurately in both time and frequency domain. Invasive and non-invasive signals were recorded simultaneously at the radial artery and compared in the frequency and time domain in haemodynamically stable intensive care unit patients. Twelve patients entered the study (8 men, 4 women, mean age 69 ± 17 years). Heart rate was 90 ± 15 bpm, systolic blood pressure 133 ± 19 mmHg and diastolic blood pressure 68 ± 15 mmHg. There was no statistical difference in the amplitude of harmonics between the invasive signal and Complior signal. When superimposing waveforms in the time domain, there was a small difference in the form factor (4.2 ± 2.8 %) and in the absolute area between the 2 waveforms (3.3 ± 1.7 mmHg·s^?1). These differences were of the same magnitude as the beat-to-beat variation of the form factor (3.3 %) and of the absolute area (3.1 mmHg·s^?1), respectively. The second systolic peak was detectable in 4 subjects, with no statistical difference between invasive and non-invasive values. The new pressure sensor of the Complior Analyse device recorded pressure waveforms accurately and could be used to perform pressure wave analysis.     

TECHNICAL NOTE: Continuous non-invasive measurement of mean blood pressure in fingers by volume-clamp and differential oscillometric method

Summary. The present study compares two different methods for non-invasive beat-to- beat finger arterial blood pressure monitoring. The measurements using the volume clamp method (FINAPRES, Ohmeda, USA) were compared with measurements applying the differential oscillometric method (UT9201 device, University of Tartu). 13 healthy volunteers were studied at rest, during head-up tilt (HUT) and during deep breathing (DB) with a fixed rate of 6 breaths/min. Blood pressure was recorded from adjacent fingers of the right hand. 150 pairs of mean blood pressure values in each subject were included for statistical evaluation. No systematic differences between the two methods were found. The difference between values (FINAPRES — UT9201) at rest was -1.1 mmHg (SD 5.5), during HUT 0.5 mmHg (SD 6.9) and during DB-3.6 mmHg (SD 7.7). The insignificant differences between the results obtained by the two independent methods allow us to conclude that both methods give reliable data on finger mean arterial pressure.     

Systolic and diastolic changes in human coronary blood flow during Valsalva manoeuvre

Valsalva manoeuvre is reported to be sometimes successful for the relief of angina pectoris. The present study investigated how haemodynamic changes produced by Valsalva manoeuvre can interact to improve the relationship between cardiac work and coronary blood flow. Ten male subjects aged 53 ± 12 years (SD) were considered. Blood velocity in the internal mammary artery, previously anastomosed to the left descending coronary artery, was studied with Doppler technique. The subjects performed Valsalva manoeuvres by expiring into a tube connected to a mercury manometer, to develop a pressure of 40 mmHg. The arterial blood pressure curve was continuously monitored with a Finapres device from a finger of the left hand. During expiratory effort, an increase in heart rate and a decrease in arterial pulse pressure were followed by a more delayed and progressive increase in mean and diastolic pressures. Systolic blood velocity markedly decreased along with the reduction in pulse pressure and increase in heart rate. By contrast, diastolic and mean coronary blood velocities did not show any significant change. Since it is known that the Valsalva manoeuvre strongly reduces stroke volume and cardiac output, it is likely that a reduction in cardiac work also takes place. Since in diastole, i.e. when the myocardial wall is better perfused, coronary blood velocity did not show any significant reduction, it is likely that unchanged perfusion in the presence of reduced cardiac work is responsible for the relief from angina sometimes observed during Valsalva manoeuvre. It is also likely that the increase in heart rate prevents the diastolic and mean blood coronary velocity from decreasing during the expiratory strain, when an increased sympathetic discharge could cause vasoconstriction through the stimulation of the coronary α‐receptors.     

Determination of left ventricular filling pressure by new echocardiographic methods in patients with coronary artery disease

Aim The present study was designed to determine the reliability of the analysis of the time difference between onset of mitral inflow and onset of early diastolic mitral annulus velocity and mean systolic strain index, and comparing them with E/E′ in the detection of increased left ventricular end-diastolic pressure (LVEDP) in patients with coronary artery disease. Methods Eighty patients (mean age: 57.2 ± 11.5 years) referred for cardiac catheterization were studied. Patients were divided into 2 groups according to LVEDP (group 1: LVEDP > 20 mmHg, n = 39 patients; group 2: LVEDP ≤20 mmHg, n = 41 patients). From the mitral inflow, peak E velocity was calculated. With tissue Doppler echocardiography, early diastolic velocity (E′) measured from the septal, lateral, inferior and lateral mitral annulus and mean value of E′ and E/E′ ratio were calculated. The time difference between onset of mitral inflow and onset of early diastolic mitral annulus velocity (T_E′-E) was calculated. From the apical chambers, the peak systolic strain value of 16 left ventricular (LV) segments was measured and the mean of these 16 segments was calculated and referred to as mean systolic strain index. Results The patients with increased LVEDP (group 1) had a higher E/E′ ratio (13.8 ± 3.4 vs. 9.9 ± 2.8, P < 0.001) and lower mean systolic strain index (11.8 ± 3.4 % vs. 13.5 ± 3.6 %, P = 0.038) than patients in group 2. The sensitivity of E/E′ > 13.42 for identifying LVEDP > 20 mmHg was 71%, with a specificity of 89%. The sensitivity of a mean systolic strain index < 10.57% for identifying LVEDP > 20 mmHg was 44%, with a specificity of 83%. T_E′-E was not significantly different between the two groups. Conclusion The decreased longitudinal function of the left ventricle is related to increased LVEDP. The E/E’ ratio, which in recent years has been used for the prediction of LV filling pressures, was a better predictor for increased LVEDP than the mean systolic strain score index and the time difference between onset of mitral inflow and onset of early diastolic mitral annulus velocity in patients with coronary artery disease.     

肝移植术后早期桡动脉与股动脉有创血压的差异研究

目的探讨肝移植术后早期患者桡动脉与股动脉有创血压监测的差异性。方法选择2015年1月至2015年12月间我院重症医学科收治的肝移植术后患者22例,对肝移植术后入ICU当时至术后1天内8个时间点,同步进行桡动脉和股动脉有创血压监测。根据股动脉收缩压水平分为3组:A组,收缩压(systolic blood pressure,SBP)90~140 mm Hg(1 mm Hg=0.133 k Pa);B组,SBP140 mm Hg;C组,SBP90 mm Hg,测量桡动脉与股动脉有创血压的差值。结果当股动脉收缩压在正常范围内,股动脉与桡动脉的收缩压、舒张压及平均动脉压无明显差异,差异无统计学意义(P0.05);当股动脉收缩压90 mm Hg时,股动脉的收缩压及平均动脉压明显高于桡动脉压,差异有统计学意义(P0.05);当股动脉收缩压140 mm Hg时,股动脉收缩压明显小于桡动脉,差异有统计学意义(P0.05)。结论肝移植术后患者早期低血压及高血压状态下,桡动脉与股动脉有创血压存在较大差异,低血压状态下桡动脉血压监测易低估患者实际血压水平,而高血压状态下表现为高估患者血压水平。