A comparison of differential oscillometric device with invasive mean arterial blood pressure monitoring in intensive care patients

Non‐invasive beat‐to‐beat mean arterial pressure (MAP) in finger arteries recorded by the differential oscillometric device was compared with MAP recorded invasively from A. radialis in 22 patients after cardiac surgery. Based on all 132 paired measurements, the MAP values measured at the radial artery were 2.7 ± 4.9 mmHg higher than those measured on fingers. Among 22 patients there were 8 patients receiving inotropic support, their difference being 2.1 ± 5.6 mmHg. The present study revealed that the mean discrepancy between the invasive radial pressure and finger pressure was small; however, patient data sets showed marked variability in average pressure differences when examined individually.     

Portapres and differential oscillometric finger blood pressure changes during deep breathing test in the assessment of BRS index

The aim of this study was to investigate changes in the finger blood pressure during a deep breathing test (DB) and to find out whether the mean blood pressure might be used as a substitute for the systolic pressure in calculations of baroreflex sensitivity from data derived from the DB test. Continuous beat-to-beat finger pressure was recorded by the volume clamp method (Portapres model 2 monitor). In addition, the mean arterial pressure was recorded by the modified oscillometric method (UT9201 beat-to-beat monitor, University of Tartu, Estonia). Fifteen healthy volunteers, aged 25-56 years, were studied. The amplitude of respiration-linked oscillations in the Portapres systolic (Psyst) and mean blood pressure (Pmean) was 22.2 +/- 8.8 and 16.6 +/- 5.8 mmHg, respectively. There was no significant difference between the amplitudes of induced changes in Pmean recorded by the two devices: the amplitude of oscillations in the mean blood pressure recorded by the differential oscillometric monitor was 16.0 +/- 5.9 mmHg. The amplitude of oscillations in Psyst correlated significantly with the amplitude of oscillations in Pmean recorded either by Portapres or by UT9201 (r=0.95 and 0.98, respectively). The high correlation between the amplitudes of oscillations in mean and systolic blood pressure allows to conclude that mean arterial pressure changes during a DB test might be used instead of systolic pressure changes in calculation of the ratio of changes in pulse interval to changes in blood pressure, which is considered to reflect baroreflex sensitivity.     

Comparison between oscillometric and invasive blood pressure monitoring during cardiac surgery

We compared values of invasive blood pressure measured intra-arterially with those measured noninvasively with an automated oscillometric monitor. Twenty-eight patients undergoing cardiac surgical procedures under general anesthesia were studied and 552 determinations were made. The two methods of measuring blood pressure correlated within the expected bounds of experimental accuracy and physiological variation. However, the correlation between invasive and noninvasive methods varied, apparently arbitrarily, with time. These disparities could not be explained by a linear combination of physiological variables recorded. Systolic determinations correlated the best and diastolic the least between the invasive and noninvasive methods. In general, the correlation was better for adults than for children, except with diastolic blood pressure.     

Pulse oximetry and finger blood pressure measurement during open-heart surgery

Pulse oximeter arterial hemoglobin oxygen saturation (SpO₂) and finger arterial pressure (FINAP) were continuously monitored before, during, and after cardiopulmonary bypass in 15 male patients. SpO₂ was monitored simultaneously with two pulse oximeters, a Nellcor N-100 and an Ohmeda Biox III. The readings obtained from the two pulse oximeters were compared with arterial blood measurements obtained using a CO-oximeter. FINAP was monitored by a prototype device (Finapres) based on the Peaz volume-clamp method. FINAP was correlated with intraarterial pressure (IAP). Both pulse oximeters functioned well before cardiopulmonary bypass. The correlations with CO-oximeter values were 0.927 for the N-100 and 0.921 for the Biox III. Immediately after the onset of cardiopulmonary bypass, the N-100 pulse oximeter stopped displaying values. The Biox III pulse oximeter continued to display values during the cardiopulmonary bypass period; the correlation with CO-oximeter values was 0.813. After cardiopulmonary bypass, the N-100 began displaying values in 2 to 10 minutes. After cardiopulmonary bypass the correlation with CO-oximeter values was 0.792 for the N-100 and 0.828 for the Biox III pulse oximeter. The Finapres finger blood pressure device functioned well in 13 of 15 patients before cardiopulmonary bypass. The mean bias ± precision of FINAP-IAP for mean pressure was 8.3±10.2 mm Hg (SD) and the correlation coefficient was 0.814. During cardiopulmonary bypass, the Finapres device functioned well in 10 of 15 patients. The mean bias precision of FINAP-IAP, for mean pressure in these 10 patients was 6.6±8.7 mm Hg and the correlation coefficient was 0.902. Immediately after cardiopulmonary bypass, the Finapres functioned well in 11 of 15 patients. The mean bias ± precision of FINAP-IAP for mean pressure was 8.6±14.1 mm Hg and the correlation coefficient was 0.533. This study documented that devices for continuous noninvasive monitoring can usually function well under the extreme conditions seen during open-heart surgery. Pulse oximeters may find a place in the monitoring of patients during open-heart surgery, although they cannot totally replace the invasive techniques. Under the conditions of diminished pulsatile peripheral blood flow we observed some differences between the two pulse oximeters.     

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.     

有创血压监测值与无创血压监测值相关性分析

目的 探讨有创血压监测值与无创血压监测值之间的线性关系,为临床血压监测提供参考.方法 选取ICU监测无创血压与有创血压的患者32例,采取自身对照的方法,同时监测患者有创血压及无创血压值,采集数据资料进行比较,并进行线性关系分析.结果 采集有效数据98对,所得数据有创血压收缩压及舒张压值分别为(146.93±21.426),(71.32±13.152) mm Hg,均高于无创血压值的(124.02±19.417),(68.86±15.251)mmHg,差异均有统计学意义(t分别为15.301,3.363;P＜0.05);有创血压与无创血压存在线性关系(r =0.880,P＜0.05).结论 有创血压与无创血压所得监测值之间有差异,不可相互替代,可使用无创血压监测值推导计算有创血压监测值.     

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.     

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.     

高血压和休克患者有创与无创血压监测的比较

目的探讨高血压、休克患者血压监测的最佳方法。方法48例ICU患者,高血压和休克各24例。每位患者分别选择左侧或右侧桡动脉穿刺行直接动脉血压连续监测,同时同侧肱动脉间断进行无创血压测定,分别记录两种方法的测量值。结果高血压患者无创测压的结果明显低于有创测压,休克患者的情况正好相反。经t检验,P均<0.01,有显著性差异。结论对于休克患者,有条件时应尽可能采用有创测压。     

人工机械瓣置换术后有创血压与无创血压监测的对照研究

目的探讨人工机械瓣置换术后有创动脉血压（ABP）与无创动脉血压（NBP）测量值的差异。方法对40例机械瓣置换术后24h患者进行有创和无创动脉血压监测比较,并对结果进行t检验。结果有创和无创动脉血压在术后早期（12h内）比较差异显著,12h以后比较无显著差异。结论机械瓣置换术后早期的有创血压与实际血压值有一定误差,采用有创血压监测,能更准确的反映血压的真实值,心内直视手术12h以后可以用无创血压监测替代有创血压监测。     

正常人血压变异性分析方法及生理意义

目的　建立正常人长时血压变异参数的正常参照值上限 (95 %可信限 ) ,并探讨其生理意义。方法　选择 6 2名正常人行 2 4h动态血压监测 ,性别和年龄匹配 ,以各时间段血压的标准差作为血压变异指标。结果　① 2 4h收缩压与舒张压变异各 <12 90、5 0 1;白昼收缩压与舒张压变异各 <11 31、4 2 3;夜间收缩压与舒张压变异各 <9 90、2 6 7。②L BPV强度依次为 2 4h收缩压变异 >白昼收缩压变异 >夜间收缩压变异 ;2 4h舒张压变异 >白昼舒张压变异 >夜间舒张压变异。③ 2 4h收缩压与舒张压变异在正常男女间比较差异均无显著意义 (P >0 0 5 ) ;不同年龄段的 2 4h收缩压变异性比较差异无显著意义 (P >0 0 5 )。结论　交感与迷走神经功能的动态平衡是血压变异得以维持在生理范畴的重要机制。增强的血压变异与体力及脑力劳动有关 ,而睡眠是降低血压变异的有效方法。     

诊室血压与家庭自测血压对降压疗效判定的影响

目的比较诊室血压与家庭自测血压(HBPM)两种方法监测结果的异同及对降压疗效判定的影响。方法分析46例门诊高血压患者在应用厄贝沙坦/厄贝沙坦氢氯噻嗪治疗中,诊室血压与HBPM监测8周的血压变化。结果两种血压监测方法观察厄贝沙坦/厄贝沙坦氢氯噻嗪的降压效果表现了良好的相关性,但HBPM的收缩压和舒张压的平均值均低于诊室血压,8周治疗血压下降的平均值略大于诊室血压的平均值,HBPM能够更加准确地评估患者血压水平,评价降压疗效,增加血压达标率。结论 HBPM作为高血压患者长期监测方法,简便易行,更能反映患者实际血压水平,是值得推荐的方法。     

社区高血压患者血压计持有及测量情况的调查分析

目的 通过对社区高血压患者的调查,了解高血压患者的血压计持有状况、家庭自测基本要求的掌握情况,为实施有针对性的护理干预提供依据.方法 对符合入选标准的社区高血压患者300例,应用自制的<高血压患者家庭自测血压基本要求调查表>进行调查分析.结果 在调查的300例高血压患者中,自己拥有血压计的有162例,血压计的持有率达54.0%.持有血压计的162例患者中,会定期检测电子血压计性能、准确性的占14.6%;测血压前至少休息5 min的占53.7%;袖带与心脏保持在同一水平的占84.5%;坐背椅坐位、测血压不讲话、不活动肢体保持安静的占83.3%;每次测血压3次,取其平均值为本次血压值的只占14.8%;贮存血压值或真实记录血压数值的占8.0%;只有13.5%的患者每天或几乎每天测量血压.结论 高血压患者血压计使用率低,对自测血压基本要求的掌握情况有待进一步的提高.     

人工机械瓣置换术后有创血压与无创血压监测的对照研究

目的 探讨人工机械瓣置换术后有创动脉血压(ABP)与无创动脉血压(NBP)测量值的差异.方法 对40例机械瓣置换术后24 h患者进行有创和无创动脉血压监测比较,并对结果 进行t检验.结果 有创和无创动脉血压在术后早期(12 h内)比较差异显著,12 h以后比较无显著差异.结论 机械瓣置换术后早期的有创血压与实际血压值有一定误差,采用有创血压监测,能更准确的反映血压的真实值,心内直视手术12 h以后可以用无创血压监测替代有创血压监测.     

血液透析患者家庭自测血压与透析日血压的相关性研究

目的 调查家庭自测血压与血液透析中心测量血压的关联度,患者在透析中心测量的血压中,哪一个能更好反映非透析日血压的状态. 方法 有56名血液透析患者参与研究,分别采集患者家庭自测血压、上机前血压及上机后不同时间点血压情况,比较不同时间点血压测量值之间的相关性.结果 上机后1h血压判定为高血压组、正常血压组与家庭自测血压判定为高血压组、正常血压组的符合率最高,分别为81.8％、61.8％.将患者按照家庭自测血压状态分为高血压组和正常血压组后,可见高血压组上机前30min的收缩压、舒张压与家庭自测收缩压、舒张压的差值最小,而正常血压组,上机前30min的收缩压、舒张压与家庭自测收缩压、舒张压的差值最大. 结论 上机后1h血压判定为高血压组、正常血压组与家庭自测血压判定为高血压组、正常血压组的符合率最高,可以通过上机后1h血压状态估计患者透析间期的血压情况.     

Noninvasive continuous blood pressure measurement during anaesthesia: A clinical evaluation of a method commonly used in measuring devices

The objective of the study was assess the utility during anaesthesia of noninvasive continuous blood pressure measurement techniques which use intermittent oscillometric blood pressure measurement for their calibration. The assessment was performed by comparing noninvasive blood pressure with intra-arterial blood pressure. The noninvasive blood pressure measurement device used for evaluation was the NCAT N-500 which uses tonometry for its continuous measurements. Fifteen patients were studied. In 10 patients the intra-arterial blood pressure curve (IBP) was recorded from the radial artery (radial artery group), and in 5 patients it was recorded from the brachial artery (brachial artery group). In all patients the oscillometrically calibrated tonometric blood pressure (OTBP) was recorded from the other arm. To discriminate between calibration dependent measurement error and tonometric measurement error, the OTBP signal was recalibrated against the IBP signal to get the intra-arterial calibrated tonometric pressure curve (ITBP). OTBP-IBP reflected the overall measurement error, ITBP-IBP the error of the tonometric measurement, and OTBP-ITBP the calibration dependent measurement error. According to criteria formulated in the discussion the accuracy and agreement of the ITBP-IBP measurements were clinical acceptable. Accuracy and agreement of OTBP-IBP and of OTBP-ITBP were not clinical acceptable. Correlation of dynamic behavior was lower for OTBP than for ITBP. A significant effect of site difference between calibration measurements and continuous measurements was not found. It is concluded that the approach of continuous noninvasive blood pressure measurement based on the combination of two different measurement methods, in which the continuous method is calibrated by the oscillometric method, lead to clinical unacceptable accuracy and agreement in the patient group studied.     

心内直视术后有创血压与无创血压监测的对照研究

[目的]探讨心内直视术后早期有创血压与无创血压监测的差异。[方法]对30例心内直视术后病人进行24h连续的有创测压和无创测压监测,进行自身对照比较。[结果]有创血压和无创血压监测在心内直视术后早期8h内收缩压差异有统计学意义(P<0.001),8h后差异无统计学意义(P>0.05);舒张压差异无统计学意义(P>0.05)。[结论]心内直视术后早期采用有创血压监测,能提供更准确的依据,心内直视手术8h以后可以用无创血压监测替代有创血压监测。     

Supraorbital artery as an alternative site for oscillometric blood pressure measurement

Objective. Noninvasive blood pressure measured from the superficial temporal artery bas been shown to correlate well with pressure in the brachial artery. The supraorbital artery may be an even better site for monitoring blood pressure on the forehead because it originates from the internal carotid artery, and it is easier to locate anatomically. This study compares mean pressure measured oscillometrically over the supraorbital artery and at the upper arm.Methods. Oscillometric signals from the supraorbital artery were recorded in 20 surgical patients under general anesthesia using a 2.5- × 1-cm bladder attached to the forehead with a self-adhesive pad. Blood pressure was measured simultaneously from the arm using a Dinamap 1846 blood pressure monitor, and the resulting data compared with the supraorbital artery measurements.Results. The mean difference between 219 pairs of blood pressure measurements, from the forehead and the arm, was 3.8 mm Hg. The standard deviation of the differences was 7.4 mm Hg. The linear regression equation for the data wasy = 0.98x + 3.25, with a standard error of estimate of 7.31 mm Hg. The correlation coefficient between the two measurements was 0.82.Conclusions. The results show that mean blood pressures measured oscillometrically from the supraorbital and brachial arteries agree and correlate well with each other. The supraorbital artery should be a good alternative site for blood pressure measurement.This article has been used by Tai-Kwong Lee as part of a dissertation, titled Noninvasive blood pressure monitoring from the supraorbital artery of the forehead by oscillometry, submitted to the Department of Bioengineering, University of Utah, in partial fulfillment of the requirements for a doctoral degree, June, 1996.This study was supported, in part, by a grant from Innerspace Medical, Inc., Irvine, CA.     

Assessment of the antihypertensive efficacy of various doses of delapril by office and ambulatory blood pressure measurement: The DEFIND study

This study was undertaken to compare and verify the antihypertensive effects of various delapril doses versus placebo on office and ambulatory blood pressure (BP). After a 2-wk placebo period, 303 patients with mild to moderate essential hypertension were randomized in a double-blind study to 8 wk of treatment with placebo, or delapril 7.5 mg twice daily, delapril 15 mg twice daily, delapril 30 mg twice daily, or delapril 30 mg once daily. BP changes versus baseline and rates of normalized office systolic blood pressure (SBP) > 140 mm Hg and diastolic blood pressure (DBP) > 90 mm Hg, as well as responder office SBP > 140 mm Hg or reduction ≥20 mm Hg and office DBP > 90 mm Hg or reduction ≥10 mm Hg, were calculated. In the intention-to-treat population (n=296), office SBP and DBP reductions were more notable with 30 mg twice daily (15.6/11.5 mm Hg) and 15 mg twice daily (14.8/12.5 mm Hg) than with other delapril regimens (30 mg once daily: 11.8/10.5 mm Hg; 7.5 mg twice daily: 12.9/10.1 mm Hg) and placebo (P< .05 for DBP;P< .01 for SBP). The same was true for frequency of responders (63.8% and 60.3%; P≤.05 vs placebo) and normalized patients (58.6% and 53.4%;P< .05 vs placebo). Analysis of ambulatory BPs confirmed the accuracy of office BPs. Drug-related adverse events occurred in 3.4% to 6.7% of patients given delapril and in 6.5% of those given placebo. The lowest effective dose of delapril, 15 mg twice daily, may be recommended as the initial dose for patients who begin treatment with this agent.     

直接血压与间接血压相关性的影响因素与假性高血压的关系

目的探讨直接血压与间接血压的相关性及其影响因素与假性高血压的关系.方法 208例临床需要行冠状动脉造影的患者,男150例,女58例,平均年龄(60.2±10.9)岁.在动脉穿刺成功后冠状动脉造影前同步测量直接血压和间接血压各3次,取平均值,造影结果由2位以上专家判断并记录.根据冠状动脉造影结果分为2组,冠状动脉正常组(104例)和冠心病组(104例).根据有无高血压病分为正常血压组(95例)和高血压病组(113例).并测量身高、体质量、臂围(AC)、腰围(WC)、臀围(HC),计算体质量指数(BMI)、腰围/臀围(WHR)、腰围/身高(WHtR)、平均血压(MBP)、直接与间接收缩压(SBP)差值(S-S)和直接与间接舒张压(DBP)差值(D-D).结果①直接血压与间接血压明显相关,SBP、MBP、DBP相关系数分别为0.88、0.76、0.58(P＜0.01).②高血压病组、冠心病组、女性直接SBP与间接SBP相关性好,而直接DBP与间接DBP相关性较差, SBP、MBP、DBP相关系数分别为0.52、0.48、0.49(P＜0.01).③直接血压总体上高于间接血压,S-S:-39～40 mm Hg(1 mm Hg=0.133 kPa),(6.35±12.50) mm Hg;D-D:-47～55 mm Hg,(5.63±11.17) mm Hg. S-S≤-10 mm Hg组与S-S＞-10 mm Hg组,S-S≤-10 mm Hg组的 AC、WC、HC、WHR、WHtR、BMI和年龄是更高的,仅BMI差别有统计学意义(P＜0.05).D-D ≤-10 mm Hg组与D-D＞-10 mm Hg比较,D-D ≤-10 mm Hg组 AC,WC,HC,WHR,WHtR 和BMI是更高的,仅AC差别有统计学意义(P＜0.05).分析AC与直接间接SBP、DBP的差值的关系发现:冠心病组AC与D-D相关,相关系数为0.27(P＜0.01).高血压组S-S与AC相关,相关系数为-0.22(P＜0.05).结论①直接血压与间接血压有明显相关性,其中SBP相关性最好,MBP次之,DBP最差(尤其是高血压病组、冠心病组和女性组);②AC是影响直接与间接血压测量值差值的重要因素,冠心病组AC影响DBP,而高血压病组AC影响SBP;③BMI高和AC大者易高估间接血压而出现假性高血压的情况.